Covariation of binaural, concurrently-measured spontaneous otoacoustic emissions.

PubMed

Penner, M J; Brauth, S E; Jastreboff, P J

1994-03-01

Simultaneous recordings of binaural spontaneous otoacoustic emissions (SOAEs) were made for 2 female subjects. For SOAEs below about 3.6 kHz measured within a testing session, the frequencies of nearby monaural and binaural SOAEs tended to move in tandem, whereas widely separated SOAEs did not. Across many testing sessions spanning a menstrual cycle, all monaural and binaural SOAE frequencies shifted in tandem. Possible mechanisms consistent with these results are discussed.

Waves on Reissner’s membrane: a mechanism for the propagation of otoacoustic emissions from the cochlea

PubMed Central

Reichenbach, Tobias; Stefanovic, Aleksandra; Nin, Fumiaki; Hudspeth, A. J.

2012-01-01

Summary Sound is detected and converted into electrical signals within the ear. The cochlea not only acts as a passive detector of sound, however, but can also produce tones itself. These otoacoustic emissions are a striking manifestation of the cochlea’s mechanical active process. A controversy remains of how these mechanical signals propagate back to the middle ear, from which they are emitted as sound. Here we combine theoretical and experimental studies to show that mechanical signals can be transmitted by waves on Reissner’s membrane, an elastic structure within the cochea. We develop a theory for wave propagation on Reissner’s membrane and its role in otoacoustic emissions. Employing a scanning laser interferometer, we measure traveling waves on Reissner’s membrane in the gerbil, guinea pig, and chinchilla. The results accord with the theory and thus support a role for Reissner’s membrane in otoacoustic emissions. PMID:22580949

Children with autism spectrum disorder have reduced otoacoustic emissions at the 1 kHz mid-frequency region.

PubMed

Bennetto, Loisa; Keith, Jessica M; Allen, Paul D; Luebke, Anne E

2017-02-01

Autism spectrum disorder (ASD) is a behaviorally diagnosed disorder of early onset characterized by impairment in social communication and restricted and repetitive behaviors. Some of the earliest signs of ASD involve auditory processing, and a recent study found that hearing thresholds in children with ASD in the mid-range frequencies were significantly related to receptive and expressive language measures. In addition, otoacoustic emissions have been used to detect reduced cochlear function in the presence of normal audiometric thresholds. We were interested then to know if otoacoustic emissions in children with normal audiometric thresholds would also reveal differences between children with ASD and typical developing (TD) controls in mid-frequency regions. Our objective was to specifically measure baseline afferent otoacoustic emissions (distortion-product otoacoustic emissions [DPOAEs]), transient-evoked otoacoustic emissions (TrOAEs), and efferent suppression, in 35 children with high-functioning ASD compared with 42 aged-matched TD controls. All participants were males 6-17 years old, with normal audiometry, and rigorously characterized via Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Schedule. Children with ASD had greatly reduced DPOAE responses in the 1 kHz frequency range, yet had comparable DPOAE responses at 0.5 and 4-8 kHz regions. Furthermore, analysis of the spectral features of TrOAEs revealed significantly decreased emissions in ASD in similar frequencies. No significant differences were noted in DPOAE or TrOAE noise floors, middle ear muscle reflex activity, or efferent suppression between children with ASD and TD controls. In conclusion, attention to specific-frequency deficits using non-invasive measures of cochlear function may be important in auditory processing impairments found in ASD. Autism Res 2017, 10: 337-345. © 2016 International Society for Autism Research, Wiley Periodicals, Inc. © 2016 International

Obtaining reliable phase-gradient delays from otoacoustic emission data.

PubMed

Shera, Christopher A; Bergevin, Christopher

2012-08-01

Reflection-source otoacoustic emission phase-gradient delays are widely used to obtain noninvasive estimates of cochlear function and properties, such as the sharpness of mechanical tuning and its variation along the length of the cochlear partition. Although different data-processing strategies are known to yield different delay estimates and trends, their relative reliability has not been established. This paper uses in silico experiments to evaluate six methods for extracting delay trends from reflection-source otoacoustic emissions (OAEs). The six methods include both previously published procedures (e.g., phase smoothing, energy-weighting, data exclusion based on signal-to-noise ratio) and novel strategies (e.g., peak-picking, all-pass factorization). Although some of the methods perform well (e.g., peak-picking), others introduce substantial bias (e.g., phase smoothing) and are not recommended. In addition, since standing waves caused by multiple internal reflection can complicate the interpretation and compromise the application of OAE delays, this paper develops and evaluates two promising signal-processing strategies, the first based on time-frequency filtering using the continuous wavelet transform and the second on cepstral analysis, for separating the direct emission from its subsequent reflections. Altogether, the results help to resolve previous disagreements about the frequency dependence of human OAE delays and the sharpness of cochlear tuning while providing useful analysis methods for future studies.

Narrow-band evoked oto-acoustic emission from ears with normal and pathologic conditions.

PubMed

Takeda, Taizo; Kakigi, Akinobu; Takebayashi, Shinji; Ohono, Satoshi; Nishioka, Rie; Nakatani, Hiroaki

2010-01-01

Evoked oto-acoustic emission (EOAE), in particular the slow component, is fragile with the inner ear lesions and is apt to disappear in impaired ears. This presence is thought to mean that inner ear is not badly damaged, and that the presence of EOAEs in early stage sudden deafness carries a good prognosis. Narrow-band EOAE analysis would open a potentially promising way to manage sensorineural deafness. The aim of present study was to evaluate the characteristics of EOAEs from pathologic ears by a narrow-band EOAE analysis, which allowed us to investigate amplitude, frequency content and latency of EOAEs simultaneously and also to easily detect weak echoes in cases with inner ear lesions. EOAEs were analyzed by investigating narrow-band frequency contents of EOAEs, filtered by a 100-Hz step of pass bandwidth in frequency regions from 1.0 to 2.0 kHz, and by 500 Hz of pass bandwidth in the frequency ranges of 0.5-1.0 and 2.0-5.0 kHz. EOAE testing was performed in 40 normal ears and 111 ears with pathologic disorders, including sudden deafness, Ménière's disease and surgically proven acoustic neurinomas. Spontaneous oto-acoustic emission was investigated in some cases. In acoustic neurinoma, especially computed tomography scan and magnetic resonance imaging tests were performed to assess the tumor size. (1) Narrow-band EOAE analysis revealed that EOAEs from normal ears were composed of two main echo trains and several sub-echoes. The main echo trains were divided into a fast component with a short latency of <10 ms and a slow component with a long latency of >10 ms. (2) EOAEs could often be detected from ears with moderate to severe hearing loss >45 dB HL in early stage sudden deafness. The prognosis of sudden deafness was good in cases where both a fast component and slow component were detected in the acute stage within 2 weeks after the deafness onset, and was pessimistic, when either or both of them failed to recover. (3) In Ménière's disease, EOAE was found

Cochlear dysfunction in hyperuricemia: otoacoustic emission analysis.

PubMed

Hamed, Sherifa A; El-Attar, Amal M

2010-01-01

The objective of this study is to provide evidence that primary hyperuricemia is associated with cochlear dysfunction as other metabolic diseases that interfere with cell metabolism. Cochlear function was evaluated in 25 subjects with asymptomatic hyperuricemia using routine diagnostic audiometry along with transient evoked and distortion product otoacoustic emissions (TEOAE and DPOAE, respectively). To support the notion that vascular compromise was a significant underlying factor for such cochlear dysfunction, we assessed vascular anatomical and functional states through measuring the common carotid artery intima-media thickness and flow velocity of the basal intracranial vessels. Compared with control subjects, reduced response levels of TEOAEs (P < .01) and amplitudes of DPOAEs (P < .001) were detected at higher frequencies. The reduced DPOAE levels at 5 kHz and TEOAEs at 4 kHz correlated significantly with uric acid (P < .05; P < .01), patients' age (P < .06; P < .05), duration since diagnosis of hyperuricemia (P < .05; P < .001), common carotid artery intima-media thickness (P < .05), mean flow velocities of middle cerebral arteries (P < .05), and vertebral arteries (P < .01). Multivariate analysis showed that the abnormalities at higher frequencies were significantly correlated with the duration and degree of hyperuricemia. These data suggest that subclinical changes in cochlear function are associated with hyperuricemia. They support the usefulness of otoacoustic emissions in early detection of cochlear dysfunction. It is possible that hyperuricemia could be accompanied by increased stiffness and/or compromise of blood supply of the outer hair cells, which will impair their electromotile response. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Diplacusis, hearing threshold and otoacoustic emissions in an episode of sudden, unilateral cochlear hearing loss.

PubMed

Knight, Richard D

2004-01-01

Limited data are available on the relationship between diplacusis and otoacoustic emissions and sudden hearing threshold changes, and the detail of the mechanism underlying diplacusis is not well understood. Data are presented here from an intensively studied single episode of sudden, non-conductive, mild hearing loss with associated binaural diplacusis, probably due to a viral infection. Treatment with steroids was administered for 1 week. This paper examines the relationships between the hearing loss, diplacusis and otoacoustic emissions during recovery on a day-by-day basis. The hearing thresholds were elevated by up to 20 dB at 4kHz and upwards, and there was an interaural pitch difference up to 12% at 4 and 8 kHz. There was also a frequency-specific change in transient evoked otoacoustic emission (TEOAE) and distortion-product otoacoustic emission (DPOAE) level. DPOAE level was reduced by up to 20 dB. with the greatest change seen when a stimulus with a wide stimulus frequency ratio was used. Frequency shifts in the 2f2-fi DPOAE fine structure corresponded to changes in the diplacusis. Complete recovery to previous levels was observed for TEOAE, DPOAE and hearing threshold. The diplacusis recovered to within normal limits after 4 weeks. The frequency shift seen in the DPOAE fine structure did not quite resolve, suggesting a very slight permanent change. The time-courses of TEOAE. diplacusis and hearing threshold were significantly different: most notably, the hearing threshold was stable over a period when the diplacusis deteriorated. This suggests that the cochlear mechanisms involved in diplacusis, hearing threshold and OAE may not be identical.

Basilar membrane vibration is not involved in the reverse propagation of otoacoustic emissions

PubMed Central

He, W.; Ren, T.

2013-01-01

To understand how the inner ear-generated sound, i.e., otoacoustic emission, exits the cochlea, we created a sound source electrically in the second turn and measured basilar membrane vibrations at two longitudinal locations in the first turn in living gerbil cochleae using a laser interferometer. For a given longitudinal location, electrically evoked basilar membrane vibrations showed the same tuning and phase lag as those induced by sounds. For a given frequency, the phase measured at a basal location led that at a more apical location, indicating that either an electrical or an acoustical stimulus evoked a forward travelling wave. Under postmortem conditions, the electrically evoked emissions showed no significant change while the basilar membrane vibration nearly disappeared. The current data indicate that basilar membrane vibration was not involved in the backward propagation of otoacoustic emissions and that sounds exit the cochlea probably through alternative media, such as cochlear fluids. PMID:23695199

Suppression effect of otoacoustic emissions in term and preterm infants.

PubMed

Jesus, Natália Oliveira de; Angrisani, Rosanna Giaffredo; Maruta, Elaine Colombo; Azevedo, Marisa Frasson de

2016-01-01

This research aims at verifying the occurrence and magnitude of suppression effect of otoacoustic emissions evoked by transient stimulus in term and preterm infants, setting a benchmark for clinical use. The study sample consisted of 40 infants, with a rage of age from five days to four months, without any risk indicators for hearing loss and otoacoustic emissions present at birth: the 20 term and 20 preterm infants spent more than five days in the Neonatal Intensive Care Unit. Linear click was presented at 65 dB Sound Pressure Level, in blocks of 15 seconds without noise, and with contralateral noise at 60 dB Sound Pressure Level. The reduced response in the presence of noise indicates positive suppression effect. Mean values of suppression were established and the comparison between the groups was analyzed statistically. Suppression occurred in 100% of the children and did not vary as a function of ear side and between the groups. All children presented suppression regardless of the group. The average suppression obtained on the total population was 0.85 dB. The minimum recommended criterion for clinical use was a reduction of 0.20 dB in the overall response.

Assessment of otoacoustic emission suppression in women with migraine and phonophobia.

PubMed

Joffily, Lucia; de Melo Tavares de Lima, Marco Antônio; Vincent, Maurice Borges; Frota, Silvana Maria Monte Coelho

2016-05-01

Given that the medial olivocochlear efferent system reduces the amplitude of otoacoustic emissions (OAE), the aim of this study was to establish whether such a pathway is affected in women with migraine and phonophobia by means of OAE suppression testing. In this prospective case-control study, 55 women (29 with migraine and phonophobia and 26 healthy women) were subjected to transient-evoked otoacoustic emission (TEOAE) testing at frequencies from 1 to 4 kHz. The amplitudes of the TEOAE response before and after exposure to contralateral noise and the magnitude of TEOAE suppression were assessed. The average TEOAE amplitudes in conditions with and without exposure to contralateral noise were not significantly different between the groups. However, the magnitude of TEOAE suppression was lower in the group with migraine; that difference was only statistically significant for frequencies 1 and 1.5 kHz (p = 0.042 and p = 0.004, respectively). In this study, women with migraine and phonophobia exhibited deficits in OAE suppression, which points to a disorder affecting the medial olivocochlear efferent system.

Compensating for ear-canal acoustics when measuring otoacoustic emissions

PubMed Central

Charaziak, Karolina K.; Shera, Christopher A.

2017-01-01

Otoacoustic emissions (OAEs) provide an acoustic fingerprint of the inner ear, and changes in this fingerprint may indicate changes in cochlear function arising from efferent modulation, aging, noise trauma, and/or exposure to harmful agents. However, the reproducibility and diagnostic power of OAE measurements is compromised by the variable acoustics of the ear canal, in particular, by multiple reflections and the emergence of standing waves at relevant frequencies. Even when stimulus levels are controlled using methods that circumvent standing-wave problems (e.g., forward-pressure-level calibration), distortion-product otoacoustic emission (DPOAE) levels vary with probe location by 10–15 dB near half-wave resonant frequencies. The method presented here estimates the initial outgoing OAE pressure wave at the eardrum from measurements of the conventional OAE, allowing one to separate the emitted OAE from the many reflections trapped in the ear canal. The emitted pressure level (EPL) represents the OAE level that would be recorded were the ear canal replaced by an infinite tube with no reflections. When DPOAEs are expressed using EPL, their variation with probe location decreases to the test–retest repeatability of measurements obtained at similar probe positions. EPL provides a powerful way to reduce the variability of OAE measurements and improve their ability to detect cochlear changes. PMID:28147590

Are human spontaneous otoacoustic emissions generated by a chain of coupled nonlinear oscillators?

PubMed

Wit, Hero P; van Dijk, Pim

2012-08-01

Spontaneous otoacoustic emissions (SOAEs) are generated by self-sustained cochlear oscillators. Properties of a computational model for a linear array of active oscillators with nearest neighbor coupling are investigated. The model can produce many experimentally well-established properties of SOAEs.

EFFECT OF SMOKING ON TRASIENTLY EVOKED OTOACOUSTIC EMISSION.

PubMed

Gegenava, Kh; Japaridze, Sh; Sharashenidze, N; Jalabadze, G; Kevanishvili, Z

2016-01-01

Evoked otoacoustic emissions, EOAEs, are proved to be sounds aroused in response to external acoustic stimulus by the cochlear outer hair cells. Transiently evoked otoacoustic emissions, TEOAEs, are the most clinically utilized EOAEs. TEOAEs are detectable in 98% of people with normal hearing, regardless of age or sex, while two ears of any individual produce similar TEOAEs waveforms. The objective of the presented study was the comparison of TEOAE magnitudes in cigarette smokers and nonsmokers. The TEOAE occurrence and characteristics in individuals of both samples with audiometrically proved hearing losses and in those without were also specifically examined. 30 smokers and and 30 nonsmokers within the age range of 30-59 years were involved in the present study after informed concent. OAEs were performed to each subject by Madsen Capella's-OAE/middle ear analyzer-GN Otometrics, (Danmark). After OAE testing each subject was performed routine pure-tone audiometry and tympanometry. Obtained results were statistically treated by the student's t-distribution. According to our results 76.6% of smokers and 3.33% of nonsmokers had marked different level decrease in TEOAE amplitude. Audiographic measurments showed altered audiogram in 6.7% of smokers and in 3.33% of nonsmokers. Based on the above mentioned results we suppose that smoking has significant influence on hearing function, especially on cochlear apparatus; At the same time, TOEAE, as a sensitive method can be used for very early detection of hearing loss, even when there are neither any subjective complains nor some changies on audiogram.

Common substructure in otoacoustic emission spectra of land vertebrates

NASA Astrophysics Data System (ADS)

Manley, Geoffrey A.; Köppl, Christine; Bergevin, Christopher

2015-12-01

In humans, a similar spectral periodicity is found in all otoacoustic emission types and in threshold fine structure. This may reflect travelling wave phase and reflectance from "structural roughness" in the organ of Corti, or entrainment and suppressive interactions between emissions. To further understand these phenomena, we have examined spontaneous otoacoustic emission (SOAE) spectra in 9 lizard species and the barn owl and find a comparable periodicity. Importantly, the frequency spacing between SOAE peaks was independent of the physical spacing and of the frequency space constants in hearing organs. In 9 lizard species, median spectral gaps lay between 219 and 461 Hz, with no correlation to papillar length (0.3 to 2.1 mm). Similarly in much longer organs: In humans (35 mm), SOAE spectral gaps vary up to 220 Hz at 4 kHz; in the barn owl (11 mm), the median SOAE peak spacing was 395Hz. In the barn owl, a very large space constant between 5 and 10 kHz (5 mm/octave) contrasts with stable SOAE spacing between 1 and 11 kHz. Similar SOAE spectral gaps across all species suggests they represent a basic frequency grating revealing local phase-dependent interactions between active hair cells, a feature not determined by macro-structural anatomy. Emission spectral spacing is independent of cochlear length, of the frequency space constant, of the existence of travelling waves or of a tectorial membrane. Our data suggest that there are greater similarities between frequency selectivity reflected at the level of the hair cells' spontaneous mechanical output (OAEs) than there are at the level of the auditory nerve, where macro-structural anatomy links hair-cell activity differentially to the neural output. Apparently, all hair-cell arrays show a similar frequency substructure not directly replicated in neural tuning.

[Otoacoustic emissions of full-term and preterm neonates].

PubMed

Kashiwamura, M; Ohwatari, R; Satoh, N; Kawanami, M; Chida, E; Sakamoto, T; Fukuda, S; Inuyama, Y

1996-01-01

Transiently evoked otoacoustic emission (TEOAE), distortion product otoacoustic emission (DPOAE), and spontaneous otoacoustic emission (SOAE) were measured in 45 full-term neonates (68 ears) and 12 preterm neonates (20 ears) with ILO88 & 92. Measurements were performed in the nursery of the obstetrics ward or NICU (not sound proof room) under natural sleeping condition after nursing. No sedating agent was used. TEOAEs were rated "good response" in 61 (89.7%) of 68 full-term neonate ears. DPOAEs were rated "good response" in 40 (71.4%) of 56 full-term neonate ears. SOAEs were detectable in 25 (62.5%) of 40 full-term neonate ears. Considering the high positive rate of TEOAE in full-term neonates and the easy and noninvasive method of measurement, we concluded that TEOAE is useful for auditory screening in neonates. There was failure to detect TEOAEs in 7 ears and the measurements were all performed within 6 days after birth. Some reports claim that residual amnion in the external auditory canal or the middle ear in the first few days after birth causes slight hearing loss. Thus, we expected that making the measurements more than 7 days after birth might yield higher "good response" rates. We sometimes found that the Total Echo Powers of TEOAEs were reduced by the poor condition of the ear probe. Thus, we must be very careful in regard to this technical problem in order to perform accurate examinations. Because of its lower "good response" rate, DPOAE was not as useful for screening as TEOAE. Because of the movements or respiratory noises of the newborn infants, it was hard to detect reliable DPOAEs, particularly in the low frequency range. On the other hand, because of its frequency specificity, particurally at high frequencies, DPOAE will be useful for detecting the partial hearing impairment such as congenital high-tone hearing impairment. It would be difficult to use SOAE as a clinical test. Because it is not an evoked response, its mechanism of generation is not

Distortion product otoacoustic emissions upon ear canal pressurization.

PubMed

Zebian, Makram; Schirkonyer, Volker; Hensel, Johannes; Vollbort, Sven; Fedtke, Thomas; Janssen, Thomas

2013-04-01

The purpose of this study was to quantify the change in distortion product otoacoustic emission (DPOAE) level upon ear canal pressurization. DPOAEs were measured on 12 normal-hearing human subjects for ear canal static pressures between -200 and +200 daPa in (50 ± 5) daPa steps. A clear dependence of DPOAE levels on the pressure was observed, with levels being highest at the maximum compliance of the middle ear, and decreasing on average by 2.3 dB per 50 daPa for lower and higher pressures. Ear canal pressurization can serve as a tool for improving the detectability of DPOAEs in the case of middle-ear dysfunction.

[Perinatal factors affecting the detection of otoacoustic emissions in vaginally delivered, healthy newborns, during the first 48 hours of life].

PubMed

Sequi-Canet, José M; Sala-Langa, María J; Collar Del Castillo, José I

2014-01-01

Most hospitals perform neonatal hearing screening because it is a very useful procedure. Otoacoustic emissions are an ideal technique for this screening. We analyse the possible influence on screening results of some perinatal factors. We collected retrospective data from 8,239 healthy newborns delivered vaginally at the maternity ward of our hospital. We compared multiple perinatal factors vs the results of otoacoustic emissions performed within the first 48 h of life, before discharge. A total of 6.4% of newborns had an abnormal response and failed the screening. Univariate and multivariate analysis showed a significant (P<.0001) positive relationship between breastfeeding and normal otoacoustic emissions (OR: 0.65). Another, less significant factor was female gender. The remaining variables, including origin, education or employment status of the mother, maternal smoking, dystocic delivery, presentation, need for resuscitation, preterm labour (34-36 weeks), weight, length and frequent maternal pathology, such as streptococcus detection, hypothyroidism, hypertension or diabetes, were not significant. Breastfeeding was the most important factor related to a normal response in otoacoustic emissions. It may improve final results and reduce the number of neonates who need to be rescheduled for a repeated test, as well as the associated anxiety and the possibility of losing patients during follow-up. These are major problems in neonatal hearing screening. Copyright © 2013 Elsevier España, S.L. All rights reserved.

A cochlear-bone wave can yield a hearing sensation as well as otoacoustic emission

PubMed Central

Tchumatchenko, Tatjana; Reichenbach, Tobias

2014-01-01

A hearing sensation arises when the elastic basilar membrane inside the cochlea vibrates. The basilar membrane is typically set into motion through airborne sound that displaces the middle ear and induces a pressure difference across the membrane. A second, alternative pathway exists, however: stimulation of the cochlear bone vibrates the basilar membrane as well. This pathway, referred to as bone conduction, is increasingly used in headphones that bypass the ear canal and the middle ear. Furthermore, otoacoustic emissions, sounds generated inside the cochlea and emitted therefrom, may not involve the usual wave on the basilar membrane, suggesting that additional cochlear structures are involved in their propagation. Here we describe a novel propagation mode within the cochlea that emerges through deformation of the cochlear bone. Through a mathematical and computational approach we demonstrate that this propagation mode can explain bone conduction as well as numerous properties of otoacoustic emissions. PMID:24954736

Transient-evoked and distortion product otoacoustic emissions: A short-term test-retest reliability study.

PubMed

Keppler, Hannah; Dhooge, Ingeborg; Maes, Leen; D'haenens, Wendy; Bockstael, Annelies; Philips, Birgit; Swinnen, Freya; Vinck, Bart

2010-02-01

Knowledge regarding the variability of transient-evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) is essential in clinical settings and improves their utility in monitoring hearing status over time. In the current study, TEOAEs and DPOAEs were measured with commercially available OAE-equipment in 56 normally-hearing ears during three sessions. Reliability was analysed for the retest measurement without probe-refitting, the immediate retest measurement with probe-refitting, and retest measurements after one hour and one week. The highest reliability was obtained in the retest measurement without probe-refitting, and decreased with increasing time-interval between measurements. For TEOAEs, the lowest reliability was seen at half-octave frequency bands 1.0 and 1.4 kHz; whereas for DPOAEs half-octave frequency band 8.0 kHz had also poor reliability. Higher primary tone level combination for DPOAEs yielded to a better reliability of DPOAE amplitudes. External environmental noise seemed to be the dominating noise source in normal-hearing subjects, decreasing the reliability of emission amplitudes especially in the low-frequency region.

Modeling Electrically Evoked Otoacoustic Emissions

NASA Astrophysics Data System (ADS)

Grosh, K.; Deo, N.; Parthasarathi, A. A.; Nuttall, A. L.; Zheng, J. F.; Ren, T. Y.

2003-02-01

Electrical evoked otoacoustic emissions (EEOAE) are used to investigate in vivo cochlear electromechanical function. Round window electrical stimulation gives rise to a broad frequency EEOAE response, from 100 Hz or below to 40 kHz in guinea pigs. Placing bipolar electrodes very close to the basilar membrane (in the scala vestibuli and scala tympani) gives rise to a much narrower frequency range of EEOAE, limited to around 20 kHz when the electrodes are placed near the 18 kHz best frequency place. Model predictions using a three dimensional fluid model in conjunction with a simple model for outer hair cell (OHC) activity are used to interpret the experimental results. The model is solved using a 2.5D finite-element formulation. Predictions show that the high-frequency limit of the excitation is determined by the spatial extent of the current stimulus (also called the current spread). The global peaks in the EEOAE spectra are interpreted as constructive interference between electrically evoked backward traveling waves and forward traveling waves reflected from the stapes. Steady-state response predictions of the model are presented.

Separating the contributions of olivocochlear and middle ear muscle reflexes in modulation of distortion product otoacoustic emission levels.

PubMed

Wolter, Nikolaus E; Harrison, Robert V; James, Adrian L

2014-01-01

Mediated by the medial olivocochlear system (MOCS), distortion product otoacoustic emission (DPOAE) levels are reduced by presentation of contralateral acoustic stimuli. Such acoustic signals can also evoke a middle ear muscle reflex (MEMR) that also attenuates recorded DPOAE levels. Our aim is to clearly differentiate these two inhibitory mechanisms and to analyze each separately, perhaps allowing the development of novel tests of hearing function. DPOAE were recorded in real time from chinchillas with normal auditory brainstem response thresholds and middle ear function. Amplitude reduction and its onset latency caused by contralateral presentation of intermittent narrow-band noise (NBN) were measured. Stapedius and tensor tympani muscle tendons were divided without disturbing the ossicular chain, and DPOAE testing was repeated. Peak reduction of (2f1 - f2) DPOAE levels occurred when the center frequency of contralateral NBN approximated the primary tone f2, indicating an f2-frequency-specific response. For a 4.5-kHz centered NBN, DPOAE (f2 = 4.4 kHz) inhibition was 0.1 dB (p < 0.001). This response remained present after tendon division, consistent with an MOCS origin. Low-frequency NBN (center frequency: 0.5 kHz) reduced otoacoustic emission levels (0.1 dB, p < 0.001) across a wide range of DPOAE frequencies. This low-frequency response was abolished by division of the middle ear muscle tendons, clearly indicating MEMR involvement. Following middle ear muscle tendon division, DPOAE inhibition by contralateral stimuli approximating the primary tone f2 persists, whereas responses evoked by lower contralateral frequencies are abolished. This distinguishes the different roles of the MOCS (f2 frequency specific) and MEMR (low frequency only) in contralateral modulation of DPOAE. This analysis helps clarify the pathways involved in an objective test that might have clinical benefit in the testing of neonates.

A common microstructure in behavioral hearing thresholds and stimulus-frequency otoacoustic emissions.

PubMed

Dewey, James B; Dhar, Sumitrajit

2017-11-01

Behavioral hearing thresholds and otoacoustic emission (OAE) spectra often exhibit quasiperiodic fluctuations with frequency. For behavioral and OAE responses to single tones-the latter referred to as stimulus-frequency otoacoustic emissions (SFOAEs)-this microstructure has been attributed to intracochlear reflections of SFOAE energy between its region of generation and the middle ear boundary. However, the relationship between behavioral and SFOAE microstructures, as well as their presumed dependence on the properties of the SFOAE-generation mechanism, have yet to be adequately examined. To address this, behavioral thresholds and SFOAEs evoked by near-threshold tones were compared in 12 normal-hearing female subjects. The microstructures observed in thresholds and both SFOAE amplitudes and delays were found to be strikingly similar. SFOAE phase accumulated an integer number of cycles between the frequencies of microstructure maxima, consistent with a dependence of microstructure periodicity on SFOAE propagation delays. Additionally, microstructure depth was correlated with SFOAE magnitude in a manner resembling that predicted by the intracochlear reflection framework, after assuming reasonable values of parameters related to middle ear transmission. Further exploration of this framework may yield more precise estimates of such parameters and provide insight into their frequency dependence.

Distortion product otoacoustic emissions: comparison of sequential vs. simultaneous presentation of primary tones.

PubMed

Kumar, U Ajith; Maruthy, Sandeep; Chandrakant, Vishwakarma

2009-03-01

Distortion product otoacoustic emissions are one form of evoked otoacoustic emissions. DPOAEs provide the frequency specific information about the hearing status in mid and high frequency regions. But in most screening protocols TEOAEs are preferred as it requires less time compared to DPOAE. This is because, in DPOAE each stimulus is presented one after the other and responses are analyzed. Grason and Stadler Incorporation 60 (GSI-60) offer simultaneous presentation of four sets of primary tones at a time and checks for the DPOAE. In this mode of presentation, all the pairs are presented at a time and following that response is extracted separately whereas, in sequential mode primaries are presented in orderly fashion one after the other. In this article simultaneous and sequential protocols were used to compare the Distortion product otoacoustic emission amplitude, noise floor and administration time in individuals with normal hearing and mild sensori-neural (SN) hearing loss. In simultaneous protocols four sets of primary tones (i.e. 8 tones) were presented together whereas, in sequential presentation mode one set of primary tones was presented each time. Simultaneous protocol was completed in less than half the time required for the completion of sequential protocol. Two techniques yielded similar results at frequencies above 1000 Hz only in normal hearing group. In SN hearing loss group simultaneous presentation yielded signifi cantly higher noise floors and distortion product amplitudes. This result challenges the use of simultaneous presentation technique in neonatal hearing screening programmes and on other pathologies. This discrepancy between two protocols may be due to some changes in biomechanical process in the cochlear and/or due to higher distortion/noise produced by the system during the simultaneous presentation mode.

Noise Levels during Aerobics and the Potential Effects on Distortion Product Otoacoustic Emissions

ERIC Educational Resources Information Center

Torre, Peter, III; Howell, Jennifer C.

2008-01-01

The purpose of this study was to measure noise levels during aerobics classes and to examine how outer hair cell (OHC) function, using distortion product otoacoustic emissions (DPOAEs), may be affected by this exposure. Fifty individuals (48 women and 2 men, ages 19-41 years) participated in 50-min aerobics classes. Noise levels were measured…

Stability of the Medial Olivocochlear Reflex as Measured by Distortion Product Otoacoustic Emissions

ERIC Educational Resources Information Center

Mishra, Srikanta K.; Abdala, Carolina

2015-01-01

Purpose: The purpose of this study was to assess the repeatability of a fine-resolution, distortion product otoacoustic emission (DPOAE)-based assay of the medial olivocochlear (MOC) reflex in normal-hearing adults. Method: Data were collected during 36 test sessions from 4 normal-hearing adults to assess short-term stability and 5 normal-hearing…

Time-frequency analysis of stimulus frequency otoacoustic emissions and their changes with efferent stimulation in guinea pigs

NASA Astrophysics Data System (ADS)

Berezina-Greene, Maria A.; Guinan, John J.

2015-12-01

To aid in understanding their origin, stimulus frequency otoacoustic emissions (SFOAEs) were measured at a series of tone frequencies using the suppression method, both with and without stimulation of medial olivocochlear (MOC) efferents, in anesthetized guinea pigs. Time-frequency analysis showed SFOAE energy peaks in 1-3 delay components throughout the measured frequency range (0.5-12 kHz). One component's delay usually coincided with the phase-gradient delay. When multiple delay components were present, they were usually near SFOAE dips. Below 2 kHz, SFOAE delays were shorter than predicted from mechanical measurements. With MOC stimulation, SFOAE amplitude was decreased at most frequencies, but was sometimes enhanced, and all SFOAE delay components were affected. The MOC effects and an analysis of model data suggest that the multiple SFOAE delay components arise at the edges of the traveling-wave peak, not far basal of the peak. Comparisons with published guinea-pig neural data suggest that the short latencies of low-frequency SFOAEs may arise from coherent reflection from an organ-of-Corti motion that has a shorter group delay than the traveling wave.

Contralateral ear occlusion for improving the reliability of otoacoustic emission screening tests.

PubMed

Papsin, Emily; Harrison, Adrienne L; Carraro, Mattia; Harrison, Robert V

2014-01-01

Newborn hearing screening is an established healthcare standard in many countries and testing is feasible using otoacoustic emission (OAE) recording. It is well documented that OAEs can be suppressed by acoustic stimulation of the ear contralateral to the test ear. In clinical otoacoustic emission testing carried out in a sound attenuating booth, ambient noise levels are low such that the efferent system is not activated. However in newborn hearing screening, OAEs are often recorded in hospital or clinic environments, where ambient noise levels can be 60-70 dB SPL. Thus, results in the test ear can be influenced by ambient noise stimulating the opposite ear. Surprisingly, in hearing screening protocols there are no recommendations for avoiding contralateral suppression, that is, protecting the opposite ear from noise by blocking the ear canal. In the present study we have compared transient evoked and distortion product OAEs measured with and without contralateral ear plugging, in environmental settings with ambient noise levels <25 dB SPL, 45 dB SPL, and 55 dB SPL. We found out that without contralateral ear occlusion, ambient noise levels above 55 dB SPL can significantly attenuate OAE signals. We strongly suggest contralateral ear occlusion in OAE based hearing screening in noisy environments.

Sex and Ear Differences in Spontaneous and Click-Evoked Otoacoustic Emissions in Young Adults

ERIC Educational Resources Information Center

Snihur, Adrian W. K.; Hampson, Elizabeth

2011-01-01

Effects of sex and handedness on the production of spontaneous and click-evoked otoacoustic emissions (OAEs) were explored in a non-hearing impaired population (ages 17-25 years). A sex difference in OAEs, either produced spontaneously (spontaneous OAEs or SOAEs) or in response to auditory stimuli (click-evoked OAEs or CEOAEs) has been reported in…

Parameters to Maximize 2f2-f1 Distortion Product Otoacoustic Emission Levels

ERIC Educational Resources Information Center

Horn, Jennifer H.; Pratt, Shiela R.; Durrant, John D.

2008-01-01

Purpose: Past research has established parameters for the 2f1-f2 distortion product otoacoustic emissions (DPOAEs) that enhance response levels (e.g., L1 - L2 = 10 dB; f2/f1 = 1.22; L1, L2 = 65, 55 dB SPL). These same parameters do not optimize 2f2-f1 DPOAEs. Therefore, this study was conducted to evaluate more completely those parameters that…

Otoacoustic Estimates of Cochlear Tuning: Testing Predictions in Macaque

NASA Astrophysics Data System (ADS)

Shera, Christopher A.; Bergevin, Christopher; Kalluri, Radha; Mc Laughlin, Myles; Michelet, Pascal; van der Heijden, Marcel; Joris, Philip X.

2011-11-01

Otoacoustic estimates of cochlear frequency selectivity suggest substantially sharper tuning in humans. However, the logic and methodology underlying these estimates remain untested by direct measurements in primates. We report measurements of frequency tuning in macaque monkeys, Old-World primates phylogenetically closer to humans than the small laboratory animals often taken as models of human hearing (e.g., cats, guinea pigs, and chinchillas). We find that measurements of tuning obtained directly from individual nerve fibers and indirectly using otoacoustic emissions both indicate that peripheral frequency selectivity in macaques is significantly sharper than in small laboratory animals, matching that inferred for humans at high frequencies. Our results validate the use of otoacoustic emissions for noninvasive measurement of cochlear tuning and corroborate the finding of sharper tuning in humans.

Testing coherent reflection in chinchilla: Auditory-nerve responses predict stimulus-frequency emissions

PubMed Central

Shera, Christopher A.; Tubis, Arnold; Talmadge, Carrick L.

2008-01-01

Coherent-reflection theory explains the generation of stimulus-frequency and transient-evoked otoacoustic emissions by showing how they emerge from the coherent “backscattering” of forward-traveling waves by mechanical irregularities in the cochlear partition. Recent published measurements of stimulus-frequency otoacoustic emissions (SFOAEs) and estimates of near-threshold basilar-membrane (BM) responses derived from Wiener-kernel analysis of auditory-nerve responses allow for comprehensive tests of the theory in chinchilla. Model predictions are based on (1) an approximate analytic expression for the SFOAE signal in terms of the BM traveling wave and its complex wave number, (2) an inversion procedure that derives the wave number from BM traveling waves, and (3) estimates of BM traveling waves obtained from the Wiener-kernel data and local scaling assumptions. At frequencies above 4 kHz, predicted median SFOAE phase-gradient delays and the general shapes of SFOAE magnitude-versus-frequency curves are in excellent agreement with the measurements. At frequencies below 4 kHz, both the magnitude and the phase of chinchilla SFOAEs show strong evidence of interference between short- and long-latency components. Approximate unmixing of these components, and association of the long-latency component with the predicted SFOAE, yields close agreement throughout the cochlea. Possible candidates for the short-latency SFOAE component, including wave-fixed distortion, are considered. Both empirical and predicted delay ratios (long-latency SFOAE delay∕BM delay) are significantly less than 2 but greater than 1. Although these delay ratios contradict models in which SFOAE generators couple primarily into cochlear compression waves, they are consistent with the notion that forward and reverse energy propagation in the cochlea occurs predominantly by means of traveling pressure-difference waves. The compelling overall agreement between measured and predicted delays suggests

Audiological characteristics of infants with abnormal transient evoked otoacoustic emission and normal auditory brainstem response.

PubMed

Huang, Lihui; Han, Demin; Guo, Ying; Liu, Sha; Cui, Xiaoyan; Mo, Lingyan; Qi, Beier; Cai, Zhenghua; Liu, Hui; En, Hui; Guo, Liansheng

2008-10-01

Audiological characteristics were investigated in 81 ears of 53 infants with abnormal transient evoked otoacoustic emission (TEOAE) and normal auditory brainstem response (ABR). The relationship between ABR and other hearing testing methods, including 40Hz auditory event-related potential (40Hz-AERP), auditory steady state response (ASSR), distortion product otoacoustic emission (DPOAE), tympanometry, and acoustic reflex, was analyzed. Of the 81 ears, 18 ears (22.2%) were normal, while 63 ears (77.8%) were abnormal according to the tests. Testing of the 40 Hz AERP (36 ears) and ASSR (45 ears) revealed that 14 ears (38.9%) and 27 ears (60.0%) were abnormal, respectively. Testing of DPOAE in 68 ears revealed that 50 ears (73.5%) were abnormal. Testing of tympanometry in 50 ears and acoustic reflex in 47 ears revealed that 9 ears (18%) and 27 ears (57.4%) were abnormal, respectively. The present data suggests that the hearing of infants cannot be sufficiently evaluated with ABR only and that it must be evaluated with integrative audiological testing methods.

[Incidence of hypoacusia secondary to hyperbilirubinaemia in a universal neonatal auditory screening programme based on otoacoustic emissions and evoked auditory potentials].

PubMed

Núñez-Batalla, Faustino; Carro-Fernández, Pilar; Antuña-León, María Eva; González-Trelles, Teresa

2008-03-01

Hyperbilirubinaemia is a neonatal risk factor that has been proved to be associated with sensorineural hearing loss. A high concentration of unconjugated bilirubin place newborn children at risk of suffering toxic effects, including hypoacusia. Review of the newborn screening results with a diagnosis of pathological hyperbilirubinaemia as part of a hearing-loss early detection protocol in the general population based on otoemissions and evoked potentials. Retrospective study of 21 590 newborn children screened between 2002 and 2006. The selection criteria for defining pathological hyperbilirubinaemia were bilirubin concentrations in excess of 14 mg/dL in pre-term infants and 20 mg/dL in full-term babies. The Universal Neonatal Hearing Screening Programme is a two-phase protocol in which all children are initially subjected to a transient otoacoustic emissions test (TOAE). Children presenting risk factors associated with auditory neuropathy were always given brainstem auditory evoked potentials (BAEP). The patients identified as having severe hyperbilirubinaemia in the neonatal period numbered 109 (0.5 %) and 96 of these (88.07 %) passed the otoacoustic emissions test at the first attempt and 13 (11.93 %) did not; 11 of the 13 children in whom the otoacoustic emissions test was repeated passed it successfully. The 2 children who failed to pass the otoacoustic emissions test has normal BAEP results; 3 (2.75 %) of the newborn infants who passed the TOAE test did not pass the BAEP. Hyperbilirubinaemia values previously considered safe may harm the hearing system and give rise to isolated problems in auditory processing without being associated with other signs of classical kernicterus. Our results show that hyperbilirubinaemia-related auditory neuropathy reveals changes over time in the audiometric outcomes.

Synchronization of spontaneous otoacoustic emissions in the tokay gecko

NASA Astrophysics Data System (ADS)

Roongthumskul, Yuttana; Hudspeth, A. J.

2018-05-01

Spontaneous otoacoustic emissions (SOAEs) are a universal feature of all classes of tetrapods. Although the generation mechanism of SOAEs are incompletely understood, these emissions are undoubtedly associated with the active process of the inner ear. In most lizards, unlike mammals and amphibians, robust SOAEs can ordinarily be detected from both ears. In this work, we investigated the interactions between emissions recorded simultaneously from the two ears of tokay geckos. We found that the frequency spectra of SOAEs from both ears of an individual animal are partially correlated: the peaks of several emissions occur at identical frequencies. To investigate the underlying mechanisms of these identical-frequency SOAEs, we perturbed the emissions from one or both ears by manipulating the pressure in the ear canals or by decreasing the local temperature in the vicinity of one inner ear. Suppression of SOAEs due to large positive pressures revealed that some identical-frequency emissions were generated unilaterally, whereas others were contributed by both ears at identical or slightly different frequencies. These bilaterally generated SOAEs became desynchronized as their frequency detuning grew sufficiently large, a phenomenon consistent with the synchronization of two active oscillators. Finally, we found that manipulations of the volume of the oral cavity or altering the impedance of the tympanum strongly affected the synchronization of SOAEs. These findings agreed with previous studies suggesting that the tokay gecko, like other lizards, exhibits strong acoustic coupling between its tympani through the oral cavity.

Effects of contralateral white noise stimulation on distortion product otoacoustic emissions in myasthenic patients.

PubMed

Di Girolamo, S; d'Ecclesia, A; Quaranta, N; Garozzo, A; Evoli, A; Paludetti, G

2001-12-01

Myasthenia gravis (MG) induces a reduction of transient evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) that reverses partially after administration of an acetylcholinesterase (AChE) inhibitor. In normal subjects a contralateral acoustic stimulation (CAS) produces an amplitude reduction of TEOAEs and DPOAEs. This effect, called contralateral suppression (CS), is mediated by the efferent auditory system. Twenty subjects affected by MG underwent DPOAE recording with and without contralateral white noise in a drug-free baseline period ('basal') and 1 h ('post') after administration of a reversible AChE inhibitor. In 'basal' condition CAS did not induce significant DPOAE amplitude changes but a paradoxical slight increase was observed. After drug administration, CAS produced a significant decrease of DPOAE amplitudes for middle frequencies (f(2) between 1306 and 2600 Hz). In normal controls CAS caused a significant decrease (P<0.001) for all frequencies. The amount of CS in controls and in the MG 'post' condition was not significantly different. The increased acetylcholine (ACh) availability following drug consumption seems to partially restore outer hair cell function and enhances their electromotility; a further influx of ACh due to CAS yields to restoration of the CS. These findings also suggest that DPOAEs may be useful in the diagnosis of MG and for monitoring the effectiveness of treatment.

High-frequency tone-pip-evoked otoacoustic emissions in chinchillas

NASA Astrophysics Data System (ADS)

Siegel, Jonathan H.; Charaziak, Karolina K.

2015-12-01

We measured otoacoustic emissions in anesthetized chinchillas evoked by short (1 ms) high-frequency (4 kHz) tone-pips (TEOAE) using either a compression or suppression method to separate the stimulus from the emission. Both methods revealed consistent features of the TEOAEs. The main spectral band of the emission generally corresponded to the spectrum of the stimulus, exhibiting a group delay similar to that of SFOAEs [9]. However, a second spectral band below 1.5 kHz, clearly separated from the low-frequency cut-off frequency of the stimulus spectrum, corresponded to an amplitude modulation of the waveform of the TEOAE. The group delay of this low-frequency band was similar to that of the main band near the probe frequency. The average level and group delay of the main band declined monotonically when revealed as the suppressor frequency was raised above the probe. The low-frequency band was more sensitive than the main band to shifts in compound action potential thresholds near the probe frequency induced by acute exposure to intense tones. Taken together, the experiments indicate that both the main and low-frequency bands of the TEOAE are generated primarily near the cochlear region maximally stimulated by the probe, but that significant contributions arise over a large region even more basal.

Contralateral suppression of transient-evoked otoacoustic emissions in children with sickle cell disease.

PubMed

Stuart, Andrew; Preast, June L

2012-01-01

In previous studies, otoacoustic emissions (OAEs) have been found to be larger in normal-hearing children with sickle cell disease (SCD). It was hypothesized that some dysfunction or reduction in the medial olivocochlear efferent suppression of outer hair cell activity was responsible for this phenomenon. To test this hypothesis, contralateral suppression of transient-evoked otoacoustic emissions (TEOAEs) was examined in children with and without SCD. Thirteen African American school-aged normal-hearing children with homozygous SCD and 13 age- and gender-matched control children participated. TEOAEs were obtained bilaterally with 80 dB peSPL nonlinear click stimuli. To examine contralateral suppression, TEOAEs were obtained with 60 dB peSPL linear click stimuli with and without a contralateral 65 dB SPL white noise suppressor. Overall and half-octave band TEOAE levels were found to be larger in children with SCD relative to the normal control children (p < 0.05), consistent with previous reports of increased OAE levels. There was no significant difference (p > 0.05) in the absolute or proportional amount of TEOAE suppression as a function of group and ear. There were also no significant correlations or linear predictive relationships between TEOAE suppression and TEOAE level for either ear or group (p > 0.05). These findings do not support the notion that increased OAE levels in children with SCD are a consequence of abnormal medial olivocochlear system function as assessed with contralateral suppression of TEOAEs.

Distortion-product otoacoustic emission reflection-component delays and cochlear tuning: estimates from across the human lifespan.

PubMed

Abdala, Carolina; Guérit, François; Luo, Ping; Shera, Christopher A

2014-04-01

A consistent relationship between reflection-emission delay and cochlear tuning has been demonstrated in a variety of mammalian species, as predicted by filter theory and models of otoacoustic emission (OAE) generation. As a step toward the goal of studying cochlear tuning throughout the human lifespan, this paper exploits the relationship and explores two strategies for estimating delay trends-energy weighting and peak picking-both of which emphasize data at the peaks of the magnitude fine structure. Distortion product otoacoustic emissions (DPOAEs) at 2f1-f2 were recorded, and their reflection components were extracted in 184 subjects ranging in age from prematurely born neonates to elderly adults. DPOAEs were measured from 0.5-4 kHz in all age groups and extended to 8 kHz in young adults. Delay trends were effectively estimated using either energy weighting or peak picking, with the former method yielding slightly shorter delays and the latter somewhat smaller confidence intervals. Delay and tuning estimates from young adults roughly match those obtained from SFOAEs. Although the match is imperfect, reflection-component delays showed the expected bend (apical-basal transition) near 1 kHz, consistent with a break in cochlear scaling. Consistent with other measures of tuning, the term newborn group showed the longest delays and sharpest tuning over much of the frequency range.

Wideband profiles of stimulus-frequency otoacoustic emissions in humans

NASA Astrophysics Data System (ADS)

Dewey, James B.; Dhar, Sumitrajit

2015-12-01

Behavioral pure-tone hearing thresholds and stimulus-frequency otoacoustic emissions (SFOAEs) were measured with a high frequency resolution from 0.5-20 kHz in 15 female participants. Stimuli were calibrated in terms of forward pressure level (FPL). SFOAE responses to 36 dB FPL probes were largest near 1 kHz and declined above 8-10 kHz, though were still measurable at frequencies approaching 16 kHz in some ears. SFOAEs typically dropped in amplitude at a frequency that was roughly one octave below the "corner" frequency of the audiogram, and one-third to one-half of an octave below the frequency where thresholds departed from highly sensitive hearing. High-frequency SFOAE responses are likely limited by a reduction in the efficiency of the underlying generation mechanism and/or a diminished region of generation as the stimulus-driven excitation approaches the basal-most portion of the cochlea.

Evidence for basal distortion-product otoacoustic emission components.

PubMed

Martin, Glen K; Stagner, Barden B; Lonsbury-Martin, Brenda L

2010-05-01

Distortion-product otoacoustic emissions (DPOAEs) were measured with traditional DP-grams and level/phase (L/P) maps in rabbits with either normal cochlear function or unique sound-induced cochlear losses that were characterized as either low-frequency or notched configurations. To demonstrate that emission generators distributed basal to the f(2) primary-tone contribute, in general, to DPOAE levels and phases, a high-frequency interference tone (IT) was presented at 1/3 of an octave (oct) above the f(2) primary-tone, and DPOAEs were re-measured as "augmented" DP-grams (ADP-grams) and L/P maps. The vector difference between the control and augmented functions was then computed to derive residual DP-grams (RDP-grams) and L/P maps. The resulting RDP-grams and L/P maps, which described the DPOAEs removed by the IT, supported the notion that basal DPOAE components routinely contribute to the generation of standard measures of DPOAEs. Separate experiments demonstrated that these components could not be attributed to the effects of the 1/3-oct IT on f(2), or DPOAEs generated by the addition of a third interfering tone. These basal components can "fill in" the lesion estimated by the commonly employed DP-gram. Thus, ADP-grams more accurately reveal the pattern of cochlear damage and may eventually lead to an improved DP-gram procedure.

Otoacoustic emission responses of the cochlea to acute and total ischemia.

PubMed

Yıldırım, Yavuz Selim; Aksoy, Fadlullah; Ozturan, Orhan; Veyseller, Bayram; Demirhan, Hasan

2013-12-01

In the present experimental study, we sought to monitor distortion product otoacoustic emissions (DPOAEs) as an indicator of cochlear function, after sudden, total, and irreversible interruption of cochlear blood flow, to provide information on the time course of cochlear response to ischemia. Twenty rats with normal hearing function were included. Complete and abrupt ischemia was provided by decapitation. DPOAEs at 3-8 kHz frequencies were recorded at baseline and exactly every consecutive minute after decapitation, until emissions in all frequencies disappeared completely. Mean DPOAE values decreased significantly and progressively after decapitation for all frequencies. The mean duration of emissions was 8.20 ± 1.96 min (minimum 3 min, maximum 11 min). The longest durations of DPOAEs were observed with 4 and 5 kHz frequencies, and 3 and 6 kHz had the shortest durations. The outer hair cells exposed to acute ischemia seem to exhibit a rapid functional loss; thus, cautious handling of the cochlear vasculature and surrounding structures is necessary in surgical interventions. Additionally, our results provide some idea of the normal tolerance range of the cochlea to ischemia, which could be useful for future studies.

Transient evoked otoacoustic emissions in rock musicians.

PubMed

Høydal, Erik Harry; Lein Størmer, Carl Christian; Laukli, Einar; Stenklev, Niels Christian

2017-09-01

Our focus in this study was the assessment of transient evoked otoacoustic emissions (TEOAEs) in a large group of rock musicians. A further objective was to analyse tinnitus among rock musicians as related to TEOAEs. The study was a cross-sectional survey of rock musicians selected at random. A control group was included at random for comparison. We recruited 111 musicians and a control group of 40 non-musicians. Testing was conducted by using clinical examination, pure tone audiometry, TEOAEs and a questionnaire. TEOAE SNR in the half-octave frequency band centred on 4 kHz was significantly lower bilaterally in musicians than controls. This effect was strongly predicted by age and pure-tone hearing threshold levels in the 3-6 kHz range. Bilateral hearing thresholds were significantly higher at 6 kHz in musicians. Twenty percent of the musicians had permanent tinnitus. There was no association between the TEOAE parameters and permanent tinnitus. Our results suggest an incipient hearing loss at 6 kHz in rock musicians. Loss of TEOAE SNR in the 4 kHz half-octave frequency band was observed, but it was related to higher mean 3-6 kHz hearing thresholds and age. A large proportion of rock musicians have permanent tinnitus.

Simultaneous measurement of noise-activated middle-ear muscle reflex and stimulus frequency otoacoustic emissions.

PubMed

Goodman, Shawn S; Keefe, Douglas H

2006-06-01

Otoacoustic emissions serve as a noninvasive probe of the medial olivocochlear (MOC) reflex. Stimulus frequency otoacoustic emissions (SFOAEs) elicited by a low-level probe tone may be the optimal type of emission for studying MOC effects because at low levels, the probe itself does not elicit the MOC reflex [Guinan et al. (2003) J. Assoc. Res. Otolaryngol. 4:521]. Based on anatomical considerations, the MOC reflex activated by ipsilateral acoustic stimulation (mediated by the crossed olivocochlear bundle) is predicted to be stronger than the reflex to contralateral stimulation. Broadband noise is an effective activator of the MOC reflex; however, it is also an effective activator of the middle-ear muscle (MEM) reflex, which can make results difficult to interpret. The MEM reflex may be activated at lower levels than measured clinically, and most previous human studies have not explicitly included measurements to rule out MEM reflex contamination. The current study addressed these issues using a higher-frequency SFOAE probe tone to test for cochlear changes mediated by the MOC reflex, while simultaneously monitoring the MEM reflex using a low-frequency probe tone. Broadband notched noise was presented ipsilaterally at various levels to elicit probe-tone shifts. Measurements are reported for 15 normal-hearing subjects. With the higher-frequency probe near 1.5 kHz, only 20% of subjects showed shifts consistent with an MOC reflex in the absence of an MEM-induced shift. With the higher-frequency probe near 3.5 kHz, up to 40% of subjects showed shifts in the absence of an MEM-induced shift. However, these responses had longer time courses than expected for MOC-induced shifts, and may have been dominated by other cochlear processes, rather than MOC reflex. These results suggest caution in the interpretation of effects observed using ipsilaterally presented acoustic activators intended to excite the MOC reflex.

Analysis of otoacoustic emissions in neonates at term and preterm.

PubMed

Cavalcante, Juliana Maria Soares; Isaac, Myriam de Lima

2013-01-01

The transient evoked otoacoustic emissions (TEOAEs) have been widely used in neonatal hearing screening. To compare the TEOAEs in newborns at term and preterm vis-à-vis the following variables: ear side, gender, frequency spectrum and gestational age. By means of a cross-sectional cohort of 66 newborns up to the 28th day of life (41 newborns at term and 25 premature babies), we recorded TEOAEs. All the individuals did not have risk indicators for hearing loss. There was a signal/noise ratio improvement with frequency increase. No differences were observed between genders and between the ears, but there were differences among the children born at term and preterm in the frequency bands at 3 kHz and 4 kHz. The TEOAEs test is important for assessing the peripheral auditory system of newborns at term and preterm, making it possible to have responses regardless of gender and gestational age.

Amplitude changes in otoacoustic emissions after exposure to industrial noise.

PubMed

Baradarnfar, Mohammad Hossein; Karamifar, Kayvan; Mehrparvar, Amir Houshang; Mollasadeghi, Abolfazl; Gharavi, Marjan; Karimi, Ghasem; Vahidy, Mohammad Reza; Baradarnfar, Amin; Mostaghaci, Mehrdad

2012-01-01

Noise-induced hearing loss (NIHL) is a frequent problem in industrial settings, especially where a high noise level is present. It is permanent, and irreversible, but preventable. Routine audiometry (an objective and time consuming) test is used for NIHL screening. Otoacoustic emissions (OAEs) are recently proposed as a more sensitive test for early diagnosis of NIHL. In this study, we aimed to compare the results of pure tone audiometry (PTA) with OAE in the diagnosis of NIHL. In a cross-sectional study on 120 workers (in three groups: Not exposed to noise, exposed to noise without NIHL and exposed to noise with NIHL), we compared the results of PTA and OAE. OAE can detect some changes in the function of hearing system in subjects exposed to noise, and these changes are apparently prior to hearing loss, which is diagnosed by PTA. OAE is a more sensitive method for the early diagnosis of cochlear damage than PTA, and can be performed in industrial settings for NIHL screening.

Deterioration in Distortion Product Otoacoustic Emissions in Auditory Neuropathy Patients With Distinct Clinical and Genetic Backgrounds.

PubMed

Kitao, Kyoko; Mutai, Hideki; Namba, Kazunori; Morimoto, Noriko; Nakano, Atsuko; Arimoto, Yukiko; Sugiuchi, Tomoko; Masuda, Sawako; Okamoto, Yasuhide; Morita, Noriko; Sakamoto, Hirokazu; Shintani, Tomoko; Fukuda, Satoshi; Kaga, Kimitaka; Matsunaga, Tatsuo

2018-04-23

Auditory neuropathy (AN) is a clinical disorder characterized by the absence of auditory brainstem response and presence of otoacoustic emissions. A gradual loss of otoacoustic emissions has been reported for some cases of AN. Such cases could be diagnosed as cochlear hearing loss and lead to misunderstanding of the pathology when patients first visit clinics after the loss of otoacoustic emissions. The purpose of this study was to investigate the time course of changes in distortion product otoacoustic emissions (DPOAEs) in association with patients' genetic and clinical backgrounds, including the use of hearing aids. DPOAE measurements from 31 patients with AN were assessed. Genetic analyses for GJB2, OTOF, and mitochondrial m.1555A> G and m.3243A> G mutations were conducted for all cases, and the analyses for CDH23 and OPA1 were conducted for the selected cases. Patients who were younger than 10 years of age at the time of AN diagnosis were designated as the pediatric AN group (22 cases), and those who were 18 years of age or older were designated as the adult AN group (9 cases). DPOAE was measured at least twice in all patients. The response rate for DPOAEs was defined and analyzed. The pediatric AN group comprised 10 patients with OTOF mutations, 1 with GJB2 mutations, 1 with OPA1 mutation, and 10 with indefinite causes. Twelve ears (27%) showed no change in DPOAE, 20 ears (46%) showed a decrease in DPOAE, and 12 ears (27%) lost DPOAE. Loss of DPOAE occurred in one ear (2%) at 0 years of age and four ears (9%) at 1 year of age. The time courses of DPOAEs in patients with OTOF mutations were divided into those with early loss and those with no change, indicating that the mechanism for deterioration of DPOAEs includes not only the OTOF mutations but also other common modifier factors. Most, but not all, AN patients who used hearing aids showed deterioration of DPOAEs after the start of using hearing aids. A few AN patients also showed deterioration of DPOAEs

Identification of neonatal hearing impairment: evaluation of transient evoked otoacoustic emission, distortion product otoacoustic emission, and auditory brain stem response test performance.

PubMed

Norton, S J; Gorga, M P; Widen, J E; Folsom, R C; Sininger, Y; Cone-Wesson, B; Vohr, B R; Mascher, K; Fletcher, K

2000-10-01

The purpose of this study was to compare the performance of transient evoked otoacoustic emissions (TEOAEs), distortion product otoacoustic emissions (DPOAEs), and auditory brain stem responses (ABRs) as tools for identification of neonatal hearing impairment. A total of 4911 infants including 4478 graduates of neonatal intensive care units, 353 well babies with one or more risk factors for hearing loss (Joint Committee on Infant Hearing, 1994) and 80 well babies without risk factor who did not pass one or more neonatal test were targeted as the potential subject pool on which test performance would be assessed. During the neonatal period, they were evaluated using TEOAEs in response to an 80 dB pSPL click, DPOAE responses to two stimulus conditions (L1 = L2 = 75 dB SPL and L1 = 65 dB SPL L2 = 50 dB SPL), and ABR elicited by a 30 dB nHL click. In an effort to describe test performance, these "at-risk" infants were asked to return for behavioral audiologic assessments, using visual reinforcement audiometry (VRA) at 8 to 12 mo corrected age, regardless of neonatal test results. Sixty-four percent of these subjects returned and reliable VRA data were obtained on 95.6% of these returnees. This approach is in contrast to previous studies in which, by necessity, efforts were made to follow only those infants who "failed" the neonatal screening tests. The accuracy of the neonatal measures in predicting hearing status at 8 to 12 mo corrected age was determined. Only those infants who provided reliable, monaural VRA test results were included in the analysis. Separate analyses were performed without regard to intercurrent events (i.e., events between the neonatal and VRA tests that could cause their results to disagree), and then after accounting for the possible influence of intercurrent events such as otitis media and late-onset or progressive hearing loss. Low refer rates were achieved for the stopping criteria used in the present study, especially when a protocol

Frequency shifts in distortion-product otoacoustic emissions evoked by swept tones

PubMed Central

Shera, Christopher A.; Abdala, Carolina

2016-01-01

When distortion-product otoacoustic emissions (DPOAEs) are evoked using stimuli whose instantaneous frequencies change rapidly and continuously with time (swept tones), the oscillatory interference pattern known as distortion-product fine structure shifts slightly along the frequency axis in the same direction as the sweep. By analogy with the temporal mechanisms thought to underlie the differing efficacies of up- and down-swept stimuli as perceptual maskers (e.g., Schroeder-phase complexes), fine-structure shifts have been ascribed to the phase distortion associated with dispersive wave propagation in the cochlea. This paper tests an alternative hypothesis and finds that the observed shifts arise predominantly as a methodological side effect of the analysis procedures commonly used to extract delayed emissions from the measured time waveform. Approximate expressions for the frequency shifts of DPOAE distortion and reflection components are derived, validated with computer simulations, and applied to account for DPOAE fine-structure shifts measured in human subjects. Component magnitudes are shown to shift twice as much as component phases. Procedures for compensating swept-tone measurements to obtain estimates of the total DPOAE and its components measured at other sweep rates or in the sinusoidal steady state are presented. PMID:27586726

[Evaluation of otoacoustic emissions in relation to brainstem evoked auditory potentials in children].

PubMed

Rado-Triveño, Julia; Alen-Ayca, Jaime

2016-01-01

To determine the validity of the use of acoustic otoacoustic emissions in comparison with the evoked potentials Auditory brainstem examination (PEATC), a study was carried out with 96 children between 0 and 4 years of age that went to Instituto Nacional de Rehabilitación in Lima, Peru. The results show a cut-off point corresponding to 1 in (+): 17.67 in right ear and 16.72 in left ear, and LR (-): 0.25 in ear right and 0.24 in left ear; ROC curve with area under the right ear curve of 0.830 (p<0.001) was obtained and in left ear of 0.829 (p<0.001). According to the results of LR (+) the sensitivity is 76% in the right ear and 65% In the left ear that coincides with the conformation of the ROC curve. In conclusion, acoustic emissions would not represent an alternative sufficiently discriminatory alternative as a screening test in this population.

Otoacoustic emissions measured in rhesus monkeys (Macaca mulatta)

NASA Astrophysics Data System (ADS)

McFadden, Dennis; Pasanen, Edward G.; Raper, Jessica; Wallen, Kim

2003-10-01

In humans, otoacoustic emissions (OAEs) are stronger in females than in males and stronger in right ears than in left. The physiological bases for these differences are unknown, but several lines of circumstantial evidence suggest that the sex difference is attributable to androgenizing mechanisms operating during prenatal development. Specifically, it appears that exposure to high levels of androgens during prenatal development diminishes the strength of the cochlear amplifiers and thus the strength of the OAEs. Sex and ear differences in OAEs have not been well studied in species other than humans. Accordingly, click-evoked OAEs and distortion-product OAEs were measured in nine female and nine male rhesus monkeys. For CEOAEs, but less clearly for DPOAEs, females exhibited significantly stronger OAEs than males. There was no consistent ear difference for either sex for either type of OAE. In order to better study the early components of the CEOAE waveform, a nonlinear procedure [Molenaar et al., Hearing Res. 143, 197-207 (2002)] was used to collect CEOAEs along with our standard (linear) procedure. This colony also contains animals of each sex that were treated with androgenic or antiandrogenic agents during prenatal development, and OAEs are also currently being measured on those animals. [Work supported by NIDCD.

Detection of Hearing Loss Using 2f2-f1 and 2f1-f2 Distortion-Product Otoacoustic Emissions

ERIC Educational Resources Information Center

Fitzgerald, Tracy S.; Prieve, Beth A.

2005-01-01

Although many distortion-product otoacoustic emissions (DPOAEs) may be measured in the ear canal in response to 2 pure tone stimuli, the majority of clinical studies have focused exclusively on the DPOAE at the frequency 2f1-f2. This study investigated another DPOAE, 2f2-f1, in an attempt to determine the following: (a) the optimal stimulus…

New clinical insights for transiently evoked otoacoustic emission protocols.

PubMed

Hatzopoulos, Stavros; Grzanka, Antoni; Martini, Alessandro; Konopka, Wieslaw

2009-08-01

The objective of the study was to optimize the area of a time-frequency analysis and then investigate any stable patterns in the time-frequency structure of otoacoustic emissions in a population of 152 healthy adults sampled over one year. TEOAE recordings were collected from 302 ears in subjects presenting normal hearing and normal impedance values. The responses were analyzed by the Wigner-Ville distribution (WVD). The TF region of analysis was optimized by examining the energy content of various rectangular and triangular TF regions. The TEOAE components from the initial and recordings 12 months later were compared in the optimized TF region. The best region for TF analysis was identified with base point 1 at 2.24 ms and 2466 Hz, base point 2 at 6.72 ms and 2466 Hz, and the top point at 2.24 ms and 5250 Hz. Correlation indices from the TF optimized region were higher, and were statistically significant, than the traditional indices in the selected time window. An analysis of the TF data within a 12-month period indicated a 85% TEOAE component similarity in 90% of the tested subjects.

Dynamics of Relaxation Processes of Spontaneous Otoacoustic Emissions

NASA Astrophysics Data System (ADS)

Murphy, William James

The dynamical response of spontaneous otoacoustic emissions (SOAEs) to suppression by ipsilateral pulsed external tones of different frequencies and levels is investigated in nine female subjects under normal conditions and in four female subjects during periods when aspirin is being administered. A simple Van der Pol limit-cycle oscillator driven by an external tone is used as an interpretive model. Typical results for both the onset of, and recovery from suppression yield 1/r_1 (where -r_1 is the negative linear component of the damping function) in the range of 2-25 msec. In accordance with the predictions of the model: (a) the relaxation time for the onset of suppression increases with the amount of suppression induced by the external tone, (b) the values of r _1 and the amplitudes of the unsuppressed emissions exhibit an inverse correlation, (c) the values inferred for r_1 are not significantly dependent on the frequency of the pulsed suppressor tone and (d) the inferred r_1 values are not significantly dependent upon the amount of suppression. In investigations involving subjects under aspirin administration, the changes in the relaxation time constants indicate that the main effect of aspirin administration is to reduce the negative damping parameter r_1. The salicylate is apparently not metabolized in some subjects whose emissions are negligibly affected by aspirin administration. A modification of the single-oscillator model is used to describe pulsed suppression data obtained from a primary SOAE (2545 Hz) which is suppressed by a neighboring secondary emission (2895 Hz). The response of the SOAE amplitude during pulsed suppression is modeled by a pair of Van der Pol limit-cycle oscillators with the primary oscillator linearly coupled to the displacement of the secondary higher-frequency one. The relaxation time constants for the onset of, and recovery from, suppression are 4.5 and 4.8 msec, respectively, for the primary SOAE and 7.5 and 10.5 msec for the

Predictors of hearing threshold levels and distortion product otoacoustic emissions among noise exposed young adults.

PubMed

Seixas, N S; Kujawa, S G; Norton, S; Sheppard, L; Neitzel, R; Slee, A

2004-11-01

To examine the relations between noise exposure and other risk factors with hearing function as measured by audiometric thresholds and distortion product otoacoustic emissions. A total of 456 subjects were studied (393 apprentices in construction trades and 63 graduate students). Hearing and peripheral auditory function were quantified using standard, automated threshold audiometry, tympanometry, and distortion product otoacoustic emissions (DPOAEs). The analysis addressed relations of noise exposure history and other risk factors with hearing threshold levels (HTLs) and DPOAEs at the baseline test for the cohort. The cohort had a mean age of 27 (7) years. The construction apprentices reported more noise exposure than students in both their occupational and non-occupational exposure histories. A strong effect of age and years of work in construction was observed at 4, 6, and 8 kHz for both HTLs and DPOAEs. Each year of construction work reported prior to baseline was associated with a 0.7 dB increase in HTL or 0.2 dB decrease DPOAE amplitude. Overall, there was a very similar pattern of effects between the HTLs and DPOAEs. This analysis shows a relatively good correspondence between the associations of noise exposures and other risk factors with DPOAEs and the associations observed with pure-tone audiometric thresholds in a young adult working population. The results provide further evidence that DPOAEs can be used to assess damage to hearing from a variety of exposures including noise. Clarifying advantages of DPOAEs or HTLs in terms of sensitivity to early manifestations of noise insults, or their utility in predicting future loss in hearing will require longitudinal follow up.

Probing cochlear tuning and tonotopy in the tiger using otoacoustic emissions.

PubMed

Bergevin, Christopher; Walsh, Edward J; McGee, JoAnn; Shera, Christopher A

2012-08-01

Otoacoustic emissions (sound emitted from the ear) allow cochlear function to be probed noninvasively. The emissions evoked by pure tones, known as stimulus-frequency emissions (SFOAEs), have been shown to provide reliable estimates of peripheral frequency tuning in a variety of mammalian and non-mammalian species. Here, we apply the same methodology to explore peripheral auditory function in the largest member of the cat family, the tiger (Panthera tigris). We measured SFOAEs in 9 unique ears of 5 anesthetized tigers. The tigers, housed at the Henry Doorly Zoo (Omaha, NE), were of both sexes and ranged in age from 3 to 10 years. SFOAE phase-gradient delays are significantly longer in tigers--by approximately a factor of two above 2 kHz and even more at lower frequencies--than in domestic cats (Felis catus), a species commonly used in auditory studies. Based on correlations between tuning and delay established in other species, our results imply that cochlear tuning in the tiger is significantly sharper than in domestic cat and appears comparable to that of humans. Furthermore, the SFOAE data indicate that tigers have a larger tonotopic mapping constant (mm/octave) than domestic cats. A larger mapping constant in tiger is consistent both with auditory brainstem response thresholds (that suggest a lower upper frequency limit of hearing for the tiger than domestic cat) and with measurements of basilar-membrane length (about 1.5 times longer in the tiger than domestic cat).

[Systematic screening of deafness at a maternity ward using evoked otoacoustic emissions: practical aspects and parental attitudes].

PubMed

Moulin, A; Ferber-Viart, C; Berland, M; Dubreuil, C; Duclaux, R

2001-09-01

Evaluation of the feasibility and parental attitudes towards a hearing screening programme using evoked otoacoustic emissions, implemented in a maternity ward in France. A hearing screening test using transiently evoked otoacoustic emissions (TEOAE) was proposed to each baby, and an anonymous questionnaire was given to parents to assess their attitudes towards the screening procedure. Although the refusal of the test reached 16% (mainly during the first two weeks of the program), more than 92% of parents judged the test as being useful, and 65% wished it to be systematically done. However, nearly 35% of parents admitted to have a low level anxiety about being unnecessarily worried by the test results. One hundred and twenty-four babies were screened. Fifty three per cent of the tests have been performed in less than ten minutes, with an average of 12.2 minutes. This duration does not include delays due to programme and babies management. False positive rate (uni or bilateral fail) was 10.5% at the first stage. Repeating the test before discharge decreased the false positive rate to 6.5%. Although limited in time, this study shows that a systematic hearing screening programme using TEOAE is possible and should be done in France. False positive rate was below 7%, and the test was considered as useful by more than 90% of parents, although knowledge about deafness in childhood and its consequences were clearly insufficient.

Distortion-product otoacoustic emission suppression tuning curves in humans

PubMed Central

Gorga, Michael P.; Neely, Stephen T.; Kopun, Judy; Tan, Hongyang

2011-01-01

Distortion-product otoacoustic emission (DPOAE) suppression data as a function of suppressor level (L3) for f2 frequencies from 0.5 to 8 kHz and L2 levels from 10 to 60 dB sensation level were used to construct suppression tuning curves (STCs). DPOAE levels in the presence of suppressors were converted into decrement versus L3 functions, and the L3 levels resulting in 3 dB decrements were derived by transformed linear regression. These L3 levels were plotted as a function of f3 to construct STCs. When f3 is represented on an octave scale, STCs were similar in shape across f2 frequency. These STCs were analyzed to provide estimates of gain (tip-to-tail difference) and tuning (QERB). Both gain and tuning decreased as L2 increased, regardless of f2, but the trend with f2 was not monotonic. A roughly linear relation was observed between gain and tuning at each frequency, such that gain increased by 4–16 dB (mean ≈ 5 dB) for every unit increase in QERB, although the pattern varied with frequency. These findings suggest consistent nonlinear processing across a wide frequency range in humans, although the nonlinear operation range is frequency dependent. PMID:21361440

Low-frequency tone-pip-evoked otoacoustic emissions originate over a broad cochlear region in chinchillas

NASA Astrophysics Data System (ADS)

Charaziak, Karolina K.; Siegel, Jonathan H.

2015-12-01

Otoacoustic emissions evoked with transient sounds (TEOAEs) are believed to originate within the tonotopic region of the stimulus in the cochlea via the same mechanisms as emissions evoked with single tones. However, we found that emissions evoked by low frequency (< 3 kHz) single-tones have an extended region of generation (> 6 mm) in chinchillas (Charaziak and Siegel, 2014, ARO Abst., 119). Here we test whether a broad region of generation for low-frequency stimuli is also a characteristic of TEOAEs evoked with 1-kHz tone pips extracted with compression and suppression methods. The TEOAE could be revealed with moderate level suppressors with frequencies extending beyond the stimulus bandwidth (up to 12.1 kHz), with the largest responses obtained with 3.1 - 4.1 kHz suppressors. There was a consistent decline in group delays of suppressor-revealed TEOAEs with increasing suppressor frequency, as expected if higher-frequency suppressors acted on more basal TEOAE generators. Effects of mid- to high-frequency acoustic trauma on TEOAE levels confirm the notion that the suppressors interact with emission components arising near the tonotopic place of the suppressor.

Dynamics of spontaneous otoacoustic emissions

NASA Astrophysics Data System (ADS)

Bergevin, Christopher; Salerno, Anthony

2015-12-01

Spontaneous otoacoustic emissions (SOAEs) have become a hallmark feature in modern theories of an `active' inner ear, given their numerous correlations to auditory function (e.g., threshold microstructure, neurophysiological tuning curves), near universality across tetrapod classes, and physiological correlates at the single hair cell level. However, while several different classes of nonlinear models exist that describe the mechanisms underlying SOAE generation (e.g., coupled limit-cycle oscillators, global standing waves), there is still disagreement as to precisely which biophysical concepts are at work. Such is further compounded by the idiosyncratic nature of SOAEs: Not all ears emit, and when present, SOAE activity can occur at seemingly arbitrary frequencies (though always within the most sensitive range of the audiogram) and in several forms (e.g., peaks, broad `baseline' plateaus). The goal of the present study was to develop new signal processing and stimulation techniques that would allow for novel features of SOAE activity to be revealed. To this end, we analyzed data from a variety of different species: human, lizard, and owl. First, we explored several strategies for examining SOAE waveforms in the absence of external stimuli to further ascertain what constitutes `self-sustained sinusoids' versus `filtered noise'. We found that seemingly similar peaks in the spectral domain could exhibit key differences in the time domain, which we interpret as providing critical information about the underlying oscillators and their coupling. Second, we introduced dynamic stimuli (swept-tones, tone bursts) at a range of levels, whose interaction with SOAEs could be visualized in the time-frequency domain. Aside from offering a readily accessible way to visualize many previously reported effects (e.g., entrainment, facilitation), we observed several new features such as subharmonic distortion generation and competing pulling/pushing effects when multiple tones were

Transiently-Evoked Otoacoustic Emissions (teoaes) in Monitoring Adult Cis-Platin Patients.

NASA Astrophysics Data System (ADS)

Ribera, John Everett

1995-01-01

There is evidence to suggest that otoacoustic emissions (OAEs) reflect the integrity of cochlear outer hair cell (OHC) function. Cis-platin (CDDP) is a potent ototoxic chemotherapeutic agent that tends to destroy or disable OHCs. Therefore, this study was designed to answer the following questions: (1) Can TEOAEs be used in monitoring for ototoxicity in adult VA oncology patients receiving CDDP treatment? (2) If so, how sensitive are TEOAEs in detecting significant changes when compared to Audiometry in a VA population? and (3) Which of several TEOAE measures is the most sensitive to changes in hearing due to CDDP ototoxicity in a VA population?. In Experiment I, VA Medical Center patients were recruited (control group) and tested using a conventional audiometer and the ILO88 Otoacoustic Analyzer on three separate days. Data from this experiment were used to develop change criteria in each of four TEOAE measures (Reproducibility, Compare, 1 kHz Band Analysis, and OAE Response) for Experiment II. Experiment II was of similar design with the exception that the subjects (experimental group) were patients enrolled from the oncology ward and were administered CDDP after the first and second test sessions. Data from both groups and all test measures revealed (1) that there was no ear effect in any of the test conditions, (2) there was a group (drug) effect, and (3) there was a frequency effect at 2 kHz. Audiometry detected changes in 56% of the experimental subjects, while the number of changes varied among the TEOAE measures studied. Compare agreed with Audiometry more often and performed better than any other TEOAE measure in detecting change. Based on these findings, incorporation of Compare into an audiometric test battery to monitor for ototoxicity in the VA population is feasible. There is evidence to suggest that as measurement techniques are refined TEOAE analysis will become a valid test for monitoring of adult CDDP patients.

Adaptive Wiener filtering for improved acquisition of distortion product otoacoustic emissions.

PubMed

Ozdamar, O; Delgado, R E; Rahman, S; Lopez, C

1998-01-01

An innovative acoustic noise canceling method using adaptive Wiener filtering (AWF) was developed for improved acquisition of distortion product otoacoustic emissions (DPOAEs). The system used one microphone placed in the test ear for the primary signal. Noise reference signals were obtained from three different sources: (a) pre-stimulus response from the test ear microphone, (b) post-stimulus response from a microphone placed near the head of the subject and (c) post-stimulus response obtained from a microphone placed in the subject's nontest ear. In order to improve spectral estimation, block averaging of a different number of single sweep responses was used. DPOAE data were obtained from 11 ears of healthy newborns in a well-baby nursery of a hospital under typical noise conditions. Simultaneously obtained recordings from all three microphones were digitized, stored and processed off-line to evaluate the effects of AWF with respect to DPOAE detection and signal-to-noise ratio (SNR) improvement. Results show that compared to standard DPOAE processing, AWF improved signal detection and improved SNR.

Otoacoustic Emissions before and after Listening to Music on a Personal Player

PubMed Central

Trzaskowski, Bartosz; Jędrzejczak, W. Wiktor; Piłka, Edyta; Cieślicka, Magdalena; Skarżyński, Henryk

2014-01-01

Background The problem of the potential impact of personal music players on the auditory system remains an open question. The purpose of the present study was to investigate, by means of otoacoustic emissions (OAEs), whether listening to music on a personal player affected auditory function. Material/Methods A group of 20 normally hearing adults was exposed to music played on a personal player. Transient evoked OAEs (TEOAEs) and distortion product OAEs (DPOAEs), as well as pure tone audiometry (PTA) thresholds, were tested at 3 stages: before, immediately after, and the next day following 30 min of exposure to music at 86.6 dBA. Results We found no statistically significant changes in OAE parameters or PTA thresholds due to listening to the music. Conclusions These results suggest that exposure to music at levels similar to those used in our study does not disturb cochlear function in a way that can be detected by means of PTA, TEOAE, or DPOAE tests. PMID:25116920

Analysis of click-evoked otoacoustic emissions by concentration of frequency and time: Preliminary results from normal hearing and Ménière's disease ears

NASA Astrophysics Data System (ADS)

Liu, Tzu-Chi; Wu, Hau-Tieng; Chen, Ya-Hui; Chen, Ya-Han; Fang, Te-Yung; Wang, Pa-Chun; Liu, Yi-Wen

2018-05-01

The presence of click-evoked (CE) otoacoustic emissions (OAEs) has been clinically accepted as an indicator of normal cochlear processing of sounds. For treatment and diagnostic purposes, however, clinicians do not typically pay attention to the detailed spectrum and waveform of CEOAEs. A possible reason is due to the lack of noise-robust signal processing tools to estimate physiologically meaningful time-frequency properties of CEOAEs, such as the latency of spectral components. In this on-going study, we applied a modern tool called concentration of frequency and time (ConceFT, [1]) to analyze CEOAE waveforms. Randomly combined orthogonal functions are used as windowing functions for time-frequency analysis. The resulting spectrograms are subject to nonlinear time-frequency reassignment so as to enhance the concentration of time-varying sinusoidal components. The results after reassignment could be further averaged across the random choice of windows. CEOAE waveforms are acquired by a linear averaging paradigm, and longitudinal data are currently being collected from patients with Ménière's disease (MD) and a control group of normal hearing subjects. When CEOAE is present, the ConceFT plots show traces of decreasing but fluctuating instantaneous frequency against time. For comparison purposes, same processing methods are also applied to analyze CEOAE data from cochlear mechanics simulation.

Contralateral suppression of transient otoacoustic emissions and sentence recognition in noise in young adults.

PubMed

Stuart, Andrew; Butler, Alyson K

2012-10-01

One purported role of the medial olivocochlear (MOC) efferent system is to reduce the effects of masking noise. MOC system functioning can be evaluated noninvasively in humans through contralateral suppression of otoacoustic emissions. It has been suggested that the strength of the MOC efferent activity should be positively associated with listening performance in noise. The objective of the study was to further explore this notion by examining contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) and sentence recognition in two noises with normal hearing young adults. A repeated measures multivariate quasi-experimental design was employed. Thirty-two normal hearing young adult females participated. Reception thresholds for sentences (RTSs) were determined monaurally and binaurally in quiet and in competing continuous and interrupted noises. Both noises had an identical power spectrum and differed only in their temporal continuity. "Release from masking" was computed by subtracting RTS signal-to-noise ratios in interrupted from continuous noise. TEOAEs were evoked with 80 dB peSPL click stimuli. To examine contralateral suppression, TEOAEs were evaluated with 60 dB peSPL click stimuli with and without a contralateral 65 dB SPL white noise suppressor. A binaural advantage was observed for RTSs in quiet and noise (p < .0001) while there was no difference between ears (p >.05). In noise, performance was superior in the interrupted noise (i.e., RTSs were lower vs. continuous noise; p < .0001). There were no statistically significant differences in TEOAE levels between ears (p >.05). There was also no significant difference in the amount of suppression between ears (p = .41). There were no significant correlations or predictive linear relations between the amount of TEOAE suppression and any indices of sentence recognition in noise (i.e., RTS signal-to-noise ratios and release from masking; p > .05). The findings are not consistent with the notion

Distortion product otoacoustic emissions provide clues to hearing mechanisms in the frog ear

NASA Astrophysics Data System (ADS)

Vassilakis, Pantelis N.; Meenderink, Sebastiaan W. F.; Narins, Peter M.

2004-12-01

2 f1-f2 and 2 f2-f1 distortion product otoacoustic emissions (DPOAEs) were recorded from both ears of male and female Rana pipiens pipiens and Rana catesbeiana. The input-output (I/O) curves obtained from the amphibian papilla (AP) of both frog species are analogous to I/O curves recorded from mammals suggesting that, similarly to the mammalian cochlea, there may be an amplification process present in the frog AP. DPOAE level dependence on L1-L2 is different from that in mammals and consistent with intermodulation distortion expectations. Therefore, if a mechanical structure in the frog inner ear is functioning analogously to the mammalian basilar membrane, it must be more broadly tuned. DPOAE audiograms were obtained for primary frequencies spanning the animals' hearing range and selected stimulus levels. The results confirm that DPOAEs are produced in both papillae, with R. catesbeiana producing stronger emissions than R. p. pipiens. Consistent with previously reported sexual dimorphism in the mammalian and anuran auditory systems, females of both species produce stronger emissions than males. Moreover, it appears that 2 f1-f2 in the frog is generated primarily at the DPOAE frequency place, while 2 f2-f1 is generated primarily at a frequency place around the primaries. Regardless of generation place, both emissions within the AP may be subject to the same filtering mechanism, possibly the tectorial membrane..

Differential responses to acoustic damage and furosemide in auditory brainstem and otoacoustic emission measures

NASA Astrophysics Data System (ADS)

Mills, David M.

2003-02-01

Characteristics of distortion product otoacoustic emissions (DPOAEs) and auditory brainstem responses (ABRs) were measured in Mongolian gerbil before and after the introduction of two different auditory dysfunctions: (1) acoustic damage with a high-intensity tone, or (2) furosemide intoxication. The goal was to find emission parameters and measures that best differentiated between the two dysfunctions, e.g., at a given ABR threshold elevation. Emission input-output or ``growth'' functions were used (frequencies f1 and f2, f2/f1=1.21) with equal levels, L1=L2, and unequal levels, with L1=L2+20 dB. The best parametric choice was found to be unequal stimulus levels, and the best measure was found to be the change in the emission threshold level, Δx. The emission threshold was defined as the stimulus level required to reach a criterion emission amplitude, in this case -10 dB SPL. (The next best measure was the change in emission amplitude at high stimulus levels, specifically that measured at L1×L2=90×70 dB SPL.) For an ABR threshold shift of 20 dB or more, there was essentially no overlap in the emission threshold measures for the two conditions, sound damage or furosemide. The dividing line between the two distributions increased slowly with the change in ABR threshold, ΔABR, and was given by Δxt=0.6 ΔABR+8 dB. For a given ΔABR, if the shift in emission threshold was more than the calculated dividing line value, Δxt, the auditory dysfunction was due to acoustic damage, if less, it was due to furosemide.

Effect of bone conduction transducer placement on distortion product otoacoustic emissions

NASA Astrophysics Data System (ADS)

Hazelbaker, Julie L.

The purpose of this study was to develop a technique to determine the magnitude of bone conducted sound in the cochlea when stimuli are delivered from three different locations on the head. Distortion product otoacoustic emissions (DPOAE) at 1000 and 2000 Hz were used as tools to determine cochlear response to stimuli introduced via air conduction and bone conduction in three subjects. The bone conduction transducer was moved to three head locations (ipsilateral mastoid, contralateral mastoid and forehead). The intensity of the emissions elicited was compared. The differences in DPOAE magnitude created by varying the location of the bone conduction transducer were compared with behavioral threshold differences with the same transducers at the same locations. It was assumed that results of behavioral measures would provide a prediction of the relationship between air and bone conducted DPOAE. However, in the current study, this was not the case. Behavioral bone conduction threshold data did not predict differences in DPOAE at different bone conduction transducer locations. This was a somewhat surprising result and should be considered further in future studies examining the properties of DPOAE elicited by bone conduction. Additionally, a wide band noise masker was introduced to the non-test ear when bone conducted stimuli were introduced to make DPOAE and behavioral test conditions as similar as possible. No great suppression effects were noted across subjects for either frequency. This was likely due to the shape and intensity of the contralateral masked used.

Changes in otoacoustic emissions during selective auditory and visual attention

PubMed Central

Walsh, Kyle P.; Pasanen, Edward G.; McFadden, Dennis

2015-01-01

Previous studies have demonstrated that the otoacoustic emissions (OAEs) measured during behavioral tasks can have different magnitudes when subjects are attending selectively or not attending. The implication is that the cognitive and perceptual demands of a task can affect the first neural stage of auditory processing—the sensory receptors themselves. However, the directions of the reported attentional effects have been inconsistent, the magnitudes of the observed differences typically have been small, and comparisons across studies have been made difficult by significant procedural differences. In this study, a nonlinear version of the stimulus-frequency OAE (SFOAE), called the nSFOAE, was used to measure cochlear responses from human subjects while they simultaneously performed behavioral tasks requiring selective auditory attention (dichotic or diotic listening), selective visual attention, or relative inattention. Within subjects, the differences in nSFOAE magnitude between inattention and attention conditions were about 2–3 dB for both auditory and visual modalities, and the effect sizes for the differences typically were large for both nSFOAE magnitude and phase. These results reveal that the cochlear efferent reflex is differentially active during selective attention and inattention, for both auditory and visual tasks, although they do not reveal how attention is improved when efferent activity is greater. PMID:25994703

Multi-tone suppression of distortion-product otoacoustic emissions in humans.

PubMed

Sieck, Nicole E; Rasetshwane, Daniel M; Kopun, Judy G; Jesteadt, Walt; Gorga, Michael P; Neely, Stephen T

2016-05-01

The purpose of this study was to investigate the combined effect of multiple suppressors. Distortion-product otoacoustic emission (DPOAE) measurements were made in normal-hearing participants. Primary tones had fixed frequencies (f2 = 4000 Hz; f1 / f2 = 1.22) and a range of levels. Suppressor tones were at three frequencies (fs = 2828, 4100, 4300 Hz) and range of levels. Decrement was defined as the attenuation in DPOAE level due to the presence of a suppressor. A measure of suppression called suppressive intensity was calculated by an equation previously shown to fit DPOAE suppression data. Suppressor pairs, which were the combination of two different frequencies, were presented at levels selected to have equal single-suppressor decrements. A hybrid model that represents a continuum between additive intensity and additive attenuation best described the results. The suppressor pair with the smallest frequency ratio produced decrements that were more consistent with additive intensity. The suppressor pair with the largest frequency ratio produced decrements at the highest level that were consistent with additive attenuation. Other suppressor-pair conditions produced decrements that were intermediate between these two alternative models. The hybrid model provides a useful framework for representing the observed range of interaction when two suppressors are combined.

Multi-tone suppression of distortion-product otoacoustic emissions in humans

PubMed Central

Sieck, Nicole E.; Rasetshwane, Daniel M.; Kopun, Judy G.; Jesteadt, Walt; Gorga, Michael P.; Neely, Stephen T.

2016-01-01

The purpose of this study was to investigate the combined effect of multiple suppressors. Distortion-product otoacoustic emission (DPOAE) measurements were made in normal-hearing participants. Primary tones had fixed frequencies (f2 = 4000 Hz; f1 / f2 = 1.22) and a range of levels. Suppressor tones were at three frequencies (fs = 2828, 4100, 4300 Hz) and range of levels. Decrement was defined as the attenuation in DPOAE level due to the presence of a suppressor. A measure of suppression called suppressive intensity was calculated by an equation previously shown to fit DPOAE suppression data. Suppressor pairs, which were the combination of two different frequencies, were presented at levels selected to have equal single-suppressor decrements. A hybrid model that represents a continuum between additive intensity and additive attenuation best described the results. The suppressor pair with the smallest frequency ratio produced decrements that were more consistent with additive intensity. The suppressor pair with the largest frequency ratio produced decrements at the highest level that were consistent with additive attenuation. Other suppressor-pair conditions produced decrements that were intermediate between these two alternative models. The hybrid model provides a useful framework for representing the observed range of interaction when two suppressors are combined. PMID:27250125

A labview-based GUI for the measurement of otoacoustic emissions.

PubMed

Wu, Ye; McNamara, D M; Ziarani, A K

2006-01-01

This paper presents the outcome of a software development project aimed at creating a stand-alone user-friendly signal processing algorithm for the estimation of distortion product otoacoustic emission (OAE) signals. OAE testing is one of the most commonly used methods of first screening of newborns' hearing. Most of the currently available commercial devices rely upon averaging long strings of data and subsequent discrete Fourier analysis to estimate low level OAE signals from within the background noise in the presence of the strong stimuli. The main shortcoming of the presently employed technology is the need for long measurement time and its low noise immunity. The result of the software development project presented here is a graphical user interface (GUI) module that implements a recently introduced adaptive technique of OAE signal estimation. This software module is easy to use and is freely disseminated on the Internet for the use of the hearing research community. This GUI module allows loading of the a priori recorded OAE signals into the workspace, and provides the user with interactive instructions for the OAE signal estimation. Moreover, the user can generate simulated OAE signals to objectively evaluate the performance capability of the implemented signal processing technique.

Theoretical study on onset of cubic distortion product otoacoustic emissions

NASA Astrophysics Data System (ADS)

Vencovský, Václav; Vetešník, Aleš

2018-05-01

The distortion product otoacoustic emissions (DPOAEs) are generated when the cochlea is stimulated by two pure tones with different frequencies f1 and f2. Onset of the DPOAE amplitude may have a nonmonotonic complex shape when the f2 is pulsed during a stationary f1 input. Observed complexities have been explained as (1) due to the secondary source of the DPOAE at the distortion product (DP) characteristic site, and (2) due to the spatial distribution of DP sources with different phases. There is also a third possibility that the complexities are due to the suppression of the f1 basilar membrane (BM) response during the f2 onset. In this study, a hydrodynamic cochlea model is used to examine influence of f1 suppression on the time course of DPOAE onset. In particular, a set of simulations was performed for frequency ratio f2/f1 = 1.26 and various levels of the primary tones (L1 and L2=30-70 dB SPL) to determine the relationship between time dependencies of the DPOAE onset and the suppression of the f1 BM response. The model predicts that suppression of the f1 BM response can cause suppression of DPOAE amplitude during the onset period.

Comparisons of transient evoked otoacoustic emissions using chirp and click stimuli

PubMed Central

Keefe, Douglas H.; Feeney, M. Patrick; Hunter, Lisa L.; Fitzpatrick, Denis F.

2016-01-01

Transient-evoked otoacoustic emission (TEOAE) responses (0.7–8 kHz) were measured in normal-hearing adult ears using click stimuli and chirps whose local frequency increased or decreased linearly with time over the stimulus duration. Chirp stimuli were created by allpass filtering a click with relatively constant incident pressure level over frequency. Chirp TEOAEs were analyzed as a nonlinear residual signal by inverse allpass filtering each chirp response into an equivalent click response. Multi-window spectral and temporal averaging reduced noise levels compared to a single-window average. Mean TEOAE levels using click and chirp stimuli were similar with respect to their standard errors in adult ears. TEOAE group delay, group spread, instantaneous frequency, and instantaneous bandwidth were similar overall for chirp and click conditions, except for small differences showing nonlinear interactions differing across stimulus conditions. These results support the theory of a similar generation mechanism on the basilar membrane for both click and chirp conditions based on coherent reflection within the tonotopic region. TEOAE temporal fine structure was invariant across changes in stimulus level, which is analogous to the intensity invariance of click-evoked basilar-membrane displacement data. PMID:27914441

Comparisons of transient evoked otoacoustic emissions using chirp and click stimuli.

PubMed

Keefe, Douglas H; Feeney, M Patrick; Hunter, Lisa L; Fitzpatrick, Denis F

2016-09-01

Transient-evoked otoacoustic emission (TEOAE) responses (0.7-8 kHz) were measured in normal-hearing adult ears using click stimuli and chirps whose local frequency increased or decreased linearly with time over the stimulus duration. Chirp stimuli were created by allpass filtering a click with relatively constant incident pressure level over frequency. Chirp TEOAEs were analyzed as a nonlinear residual signal by inverse allpass filtering each chirp response into an equivalent click response. Multi-window spectral and temporal averaging reduced noise levels compared to a single-window average. Mean TEOAE levels using click and chirp stimuli were similar with respect to their standard errors in adult ears. TEOAE group delay, group spread, instantaneous frequency, and instantaneous bandwidth were similar overall for chirp and click conditions, except for small differences showing nonlinear interactions differing across stimulus conditions. These results support the theory of a similar generation mechanism on the basilar membrane for both click and chirp conditions based on coherent reflection within the tonotopic region. TEOAE temporal fine structure was invariant across changes in stimulus level, which is analogous to the intensity invariance of click-evoked basilar-membrane displacement data.

Fluid Shifts: Otoacoustical Emission Changes in Response to Posture and Lower Body Negative Pressure

NASA Technical Reports Server (NTRS)

Melgoza, R.; Kemp, D.; Ebert, D.; Danielson, R.; Stenger, M.; Hargens, A.; Dulchavsky, S.

2016-01-01

INTRODUCTION: The purpose of the NASA Fluid Shifts Study is to characterize fluid distribution and compartmentalization associated with long-duration spaceflight and to correlate these findings with vision changes and other elements of the visual impairment and intracranial pressure (VIIP) syndrome. VIIP signs and symptoms, as well as postflight lumbar puncture data, suggest that elevated intracranial pressure (ICP) may be associated with spaceflight-induced cephalad fluid shifts, but this hypothesis has not been tested. Due to the invasive nature of direct measures of ICP, a noninvasive technique of monitoring ICP is desired for use during spaceflight. The phase angle and amplitude of otoacoustic emissions (OAEs) have been shown to be sensitive to posture change and ICP (1, 2), therefore use of OAEs is an attractive option. OAEs are low-level sounds produced by the sensory cells of the cochlea in response to auditory stimulation. These sounds travel peripherally from the cochlea, through the oval window, to the ear canal where they can be recorded. OAE transmission is sensitive to changes in the stiffness of the oval window, occurring as a result of changes in cochlear pressure. Increased stiffness of the oval window largely affects the transmission of sound from the cochlea at frequencies between 800 Hz and 1600 Hz. OAEs can be self-recorded in the laboratory or on the ISS using a handheld device. Our primary objectives regarding OAE measures in this experiment were to 1) validate this method during preflight testing of each crewmember (while sitting, supine and in head-down tilt position), and 2) determine if OAE measures (and presumably ICP) are responsive to lower body negative pressure and to spaceflight. METHODS: Distortion-product otoacoustic emissions (DPOAEs) and transient evoked otoacoustic emissions (TEOAEs) were recorded preflight using the Otoport Advance OAE system (Otodynamics Ltd., Hatfield, UK). Data were collected in four conditions (seated

Mammalian spontaneous otoacoustic emissions are amplitude-stabilized cochlear standing waves.

PubMed

Shera, Christopher A

2003-07-01

Mammalian spontaneous otoacoustic emissions (SOAEs) have been suggested to arise by three different mechanisms. The local-oscillator model, dating back to the work of Thomas Gold, supposes that SOAEs arise through the local, autonomous oscillation of some cellular constituent of the organ of Corti (e.g., the "active process" underlying the cochlear amplifier). Two other models, by contrast, both suppose that SOAEs are a global collective phenomenon--cochlear standing waves created by multiple internal reflection--but differ on the nature of the proposed power source: Whereas the "passive" standing-wave model supposes that SOAEs are biological noise, passively amplified by cochlear standing-wave resonances acting as narrow-band nonlinear filters, the "active" standing-wave model supposes that standing-wave amplitudes are actively maintained by coherent wave amplification within the cochlea. Quantitative tests of key predictions that distinguish the local-oscillator and global standing-wave models are presented and shown to support the global standing-wave model. In addition to predicting the existence of multiple emissions with a characteristic minimum frequency spacing, the global standing-wave model accurately predicts the mean value of this spacing, its standard deviation, and its power-law dependence on SOAE frequency. Furthermore, the global standing-wave model accounts for the magnitude, sign, and frequency dependence of changes in SOAE frequency that result from modulations in middle-ear stiffness. Although some of these SOAE characteristics may be replicable through artful ad hoc adjustment of local-oscillator models, they all arise quite naturally in the standing-wave framework. Finally, the statistics of SOAE time waveforms demonstrate that SOAEs are coherent, amplitude-stabilized signals, as predicted by the active standing-wave model. Taken together, the results imply that SOAEs are amplitude-stabilized standing waves produced by the cochlea acting as a

Modeling Signal-to-Noise Ratio of Otoacoustic Emissions in Workers Exposed to Different Industrial Noise Levels

PubMed Central

Nassiri, Parvin; Zare, Sajad; Monazzam, Mohammad R.; Pourbakht, Akram; Azam, Kamal; Golmohammadi, Taghi

2016-01-01

Introduction: Noise is considered as the most common cause of harmful physical effects in the workplace. A sound that is generated from within the inner ear is known as an otoacoustic emission (OAE). Distortion-product otoacoustic emissions (DPOAEs) assess evoked emission and hearing capacity. The aim of this study was to assess the signal-to-noise ratio in different frequencies and at different times of the shift work in workers exposed to various levels of noise. It was also aimed to provide a statistical model for signal-to-noise ratio (SNR) of OAEs in different frequencies based on the two variables of sound pressure level (SPL) and exposure time. Materials and Methods: This case–control study was conducted on 45 workers during autumn 2014. The workers were divided into three groups based on the level of noise exposure. The SNR was measured in frequencies of 1000, 2000, 3000, 4000, and 6000 Hz in both ears, and in three different time intervals during the shift work. According to the inclusion criterion, SNR of 6 dB or greater was included in the study. The analysis was performed using repeated measurements of analysis of variance, spearman correlation coefficient, and paired samples t-test. Results: The results showed that there was no statistically significant difference between the three exposed groups in terms of the mean values of SNR (P > 0.05). Only in signal pressure levels of 88 dBA with an interval time of 10:30–11:00 AM, there was a statistically significant difference between the right and left ears with the mean SNR values of 3000 frequency (P = 0.038). The SPL had a significant effect on the SNR in both the right and left ears (P = 0.023, P = 0.041). The effect of the duration of measurement on the SNR was statistically significant in both the right and left ears (P = 0.027, P < 0.001). Conclusion: The findings of this study demonstrated that after noise exposure during the shift, SNR of OAEs reduced from the beginning to the end of the shift

Pressurized transient otoacoustic emissions measured using click and chirp stimuli.

PubMed

Keefe, Douglas H; Patrick Feeney, M; Hunter, Lisa L; Fitzpatrick, Denis F; Sanford, Chris A

2018-01-01

Transient-evoked otoacoustic emission (TEOAE) responses were measured in normal-hearing adult ears over frequencies from 0.7 to 8 kHz, and analyzed with reflectance/admittance data to measure absorbed sound power and the tympanometric peak pressure (TPP). The mean TPP was close to ambient. TEOAEs were measured in the ear canal at ambient pressure, TPP, and fixed air pressures from 150 to -200 daPa. Both click and chirp stimuli were used to elicit TEOAEs, in which the incident sound pressure level was constant across frequency. TEOAE levels were similar at ambient and TPP, and for frequencies from 0.7 to 2.8 kHz decreased with increasing positive and negative pressures. At 4-8 kHz, TEOAE levels were larger at positive pressures. This asymmetry is possibly related to changes in mechanical transmission through the ossicular chain. The mean TEOAE group delay did not change with pressure, although small changes were observed in the mean instantaneous frequency and group spread. Chirp TEOAEs measured in an adult ear with Eustachian tube dysfunction and TPP of -165 daPa were more robust at TPP than at ambient. Overall, results demonstrate the feasibility and clinical potential of measuring TEOAEs at fixed pressures in the ear canal, which provide additional information relative to TEOAEs measured at ambient pressure.

Otoacoustic emissions measured in children diagnosed with attention-deficit/hyperactivity disorder

NASA Astrophysics Data System (ADS)

McFadden, Dennis; Westhafer, J. Gregory; Pasanen, Edward G.; Tucker, David M.; Carlson, Caryn L.

2003-10-01

Attention-deficit/hyperactivity disorder (ADHD) is generally acknowledged to be more prevalent in males than in females. Further, some precursors to ADHD appear early in life. Together these facts suggest that ADHD may be influenced by androgenic mechanisms operating early in development. This reasoning raises the question of whether the otoacoustic emissions (OAEs) of children with ADHD are masculinized. Click-evoked OAEs were measured for one click level in 8 boys and 3 girls diagnosed as ADHD/Combined, in 11 males and 5 females diagnosed as ADHD/Inattentive (IA), and in 17 male and 18 female controls. The ages of these samples ranged between 7 and 15. As in adults, the CEOAEs of the control males were weaker than those of the control females. Further, the CEOAEs of the ADHD/IA males were weaker than in the control males (a hypermasculinization) and the CEOAEs of the IA females were weaker than in the female controls (a masculinization). The CEOAEs of the Combined groups were slightly stronger (feminized) than those of the control males and females. One interpretation is that the IA subgroup of ADHD boys and girls (but not the Combined subgroup) was exposed to higher-than-normal levels of androgens sometime early in development. [Work supported by NIDCD.

Evaluation of cochlear involvement by distortion product otoacoustic emission in Behçet's disease.

PubMed

Dagli, Muharrem; Eryilmaz, Adil; Tanrikulu, Salih; Aydin, Acar; Gonul, Muzeyyen; Gul, Ulker; Gocer, Celil

2008-09-01

The aim of this study was to investigate cochlear involvement in patients with Behçet's disease. Twenty-six Behçet's disease patients (52 ears) and 24 sex and age-matched healthy control subjects (48 ears) were included in the study. Pure-tone audiometry at frequencies 250, 500, 1000, 2000, 4000, 6000 Hz, immittance measures including tympanometry and acoustic reflex testing and DPOAE (distortion product otoacoustic emission) testing were performed in the patients and controls. A sensorineural hearing loss was found in eight patients (30.7%) as it was bilateral in five and unilateral in three patients. Although no typical audiometric configuration was found, one patient had a flat type audiogram, and the others had a high frequency hearing loss. The DPOAE responses of the patients and controls were significantly different in all frequencies (p<0.05). These results indicate that cochlea is affected by damage of outer hair cells in Behçet's disease.

Suppression tuning of distortion-product otoacoustic emissions: Results from cochlear mechanics simulation

PubMed Central

Liu, Yi-Wen; Neely, Stephen T.

2013-01-01

This paper presents the results of simulating the acoustic suppression of distortion-product otoacoustic emissions (DPOAEs) from a computer model of cochlear mechanics. A tone suppressor was introduced, causing the DPOAE level to decrease, and the decrement was plotted against an increasing suppressor level. Suppression threshold was estimated from the resulting suppression growth functions (SGFs), and suppression tuning curves (STCs) were obtained by plotting the suppression threshold as a function of suppressor frequency. Results show that the slope of SGFs is generally higher for low-frequency suppressors than high-frequency suppressors, resembling those obtained from normal hearing human ears. By comparing responses of normal (100%) vs reduced (50%) outer-hair-cell sensitivities, the model predicts that the tip-to-tail difference of the STCs correlates well with that of intra-cochlear iso-displacement tuning curves. The correlation is poorer, however, between the sharpness of the STCs and that of the intra-cochlear tuning curves. These results agree qualitatively with what was recently reported from normal-hearing and hearing-impaired human subjects, and examination of intra-cochlear model responses can provide the needed insight regarding the interpretation of DPOAE STCs obtained in individual ears. PMID:23363112

Spontaneous otoacoustic emissions, threshold microstructure, and psychophysical tuning over a wide frequency range in humansa

PubMed Central

Baiduc, Rachael R.; Lee, Jungmee; Dhar, Sumitrajit

2014-01-01

Hearing thresholds have been shown to exhibit periodic minima and maxima, a pattern known as threshold microstructure. Microstructure has previously been linked to spontaneous otoacoustic emissions (SOAEs) and normal cochlear function. However, SOAEs at high frequencies (>4 kHz) have been associated with hearing loss or cochlear pathology in some reports. Microstructure would not be expected near these high-frequency SOAEs. Psychophysical tuning curves (PTCs), the expression of frequency selectivity, may also be altered by SOAEs. Prior comparisons of tuning between ears with and without SOAEs demonstrated sharper tuning in ears with emissions. Here, threshold microstructure and PTCs were compared at SOAE frequencies ranging between 1.2 and 13.9 kHz using subjects without SOAEs as controls. Results indicate: (1) Threshold microstructure is observable in the vicinity of SOAEs of all frequencies; (2) PTCs are influenced by SOAEs, resulting in shifted tuning curve tips, multiple tips, or inversion. High frequency SOAEs show a greater effect on PTC morphology. The influence of most SOAEs at high frequencies on threshold microstructure and PTCs is consistent with those at lower frequencies, suggesting that high-frequency SOAEs reflect the same cochlear processes that lead to SOAEs at lower frequencies. PMID:24437770

Application of distortion product otoacoustic emissions to inflation of the eustachian tube in low frequency tinnitus with normal hearing.

PubMed

Wang, Hui; Song, Ningying; Li, Xujing; Lv, Hongguang

2013-06-01

This study was designed to investigate the applications of distortion product otoacoustic emissions to assess the efficacy of eustachian tube inflation on low frequency tinnitus with normal hearing. Ninety-four patients (155 ears) suffering from subjective tinnitus with normal hearing sensitivity participated in this study. Control group consists of fifty volunteers (100 ears) without tinnitus. They were subjected to full history taking, otoscopy, basic audiologic evaluation and distortion product otoacoustic emissions (DPOAE). As for the patients with decreased DPOAE amplitude over a limited frequency range from 0.5 to 1kHz, we offered nose dropping and tubal inflation for a week and DPOAE was preformed again. The patients were followed up for a month. 34.8% DPOAE-gram showed decreased amplitude at the frequencies from 0.5 to 1kHz in tinnitus group and "the ring" is mostly lower in pitch. Among the patients accepted the treatment of eustachian tube inflation, 16.7% the tinnitus disappeared, no recurrence within one month; 66.67% the tinnitus reduced within one month. 95.5% the amplitude of DPOAE showed improved over the limited frequency. 16.7% the tinnitus still existed. The changes of the mechanical properties of ossicular chain or the tympanic membrane influenced by tympanum pressure may cause tinnitus, which is sub-clinical prior to the changes of audiometry and tympanometry. The low frequency tinnitus may gain transitory relief from ringing with the tubal inflation. DPOAE was proved to be a useful tool in the evaluation of the efficacy of tubal inflation on low frequency tinnitus with normal hearing. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Distortion product otoacoustic emissions in young adult and geriatric cats.

PubMed

Strain, George M; McGee, Kain A

2017-03-01

Recordings of distortion product otoacoustic emissions (DPOAEs) were taken from 15 geriatric cats (mean age ± standard deviation, SD, 13.6 ± 2.7 years; range 10.2-19.4 years) and 12 young adult control cats (mean ± SD 4.6 ± 0.5 years; range 3.4-5 years) to identify frequency-specific age-related changes in cochlear responses. Recordings were performed for primary frequencies from 2 to 12 kHz in 2 kHz increments. Cats were considered to be geriatric > 11.9 ± 1.9 years of age. Brainstem auditory evoked response (BAER) recordings were also made for subjective comparison with DPOAE responses. No differences in DPOAE response amplitudes were observed at any tested frequency in geriatric cats compared to control cats, reflecting an apparent absence of loss of cochlear outer hair cells along the length of the cochlea. No linear regression relationships were found for DPOAE response amplitude versus age in geriatric cats, despite the progressive nature of age-related hearing loss in other species. The absence of reductions in response at any of the tested frequencies in cats within the age span where cats are considered to be geriatric indicates that age-related hearing loss, if it does develop in cats, begins later in the life span of cats than in dogs or human beings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Click-evoked otoacoustic emissions in children and adolescents with gender identity disorder.

PubMed

Burke, Sarah M; Menks, Willeke M; Cohen-Kettenis, Peggy T; Klink, Daniel T; Bakker, Julie

2014-11-01

Click-evoked otoacoustic emissions (CEOAEs) are echo-like sounds that are produced by the inner ear in response to click-stimuli. CEOAEs generally have a higher amplitude in women compared to men and neonates already show a similar sex difference in CEOAEs. Weaker responses in males are proposed to originate from elevated levels of testosterone during perinatal sexual differentiation. Therefore, CEOAEs may be used as a retrospective indicator of someone's perinatal androgen environment. Individuals diagnosed with Gender Identity Disorder (GID), according to DSM-IV-TR, are characterized by a strong identification with the other gender and discomfort about their natal sex. Although the etiology of GID is far from established, it is hypothesized that atypical levels of sex steroids during a critical period of sexual differentiation of the brain might play a role. In the present study, we compared CEOAEs in treatment-naïve children and adolescents with early-onset GID (24 natal boys, 23 natal girls) and control subjects (65 boys, 62 girls). We replicated the sex difference in CEOAE response amplitude in the control group. This sex difference, however, was not present in the GID groups. Boys with GID showed stronger, more female-typical CEOAEs whereas girls with GID did not differ in emission strength compared to control girls. Based on the assumption that CEOAE amplitude can be seen as an index of relative androgen exposure, our results provide some evidence for the idea that boys with GID may have been exposed to lower amounts of androgen during early development in comparison to control boys.

Transmission of infrasonic pressure waves from cerebrospinal to intralabyrinthine fluids through the human cochlear aqueduct: Non-invasive measurements with otoacoustic emissions.

PubMed

Traboulsi, Raghida; Avan, Paul

2007-11-01

The cochlear aqueduct connecting intralabyrinthine and cerebrospinal fluids (CSF) acts as a low-pass filter that should be able to transmit infrasonic pressure waves from CSF to cochlea. Recent experiments have shown that otoacoustic emissions generated at 1kHz respond to pressure-related stapes impedance changes with a change in phase relative to the generator tones, and provide a non-invasive means of assessing intracochlear pressure changes. In order to characterize the transmission to the cochlea of CSF pressure waves due to respiration, the distortion-product otoacoustic emissions (DPOAE) of 12 subjects were continuously monitored around 1kHz at a rate of 6.25epochs/s, and their phase relative to the stimulus tones was extracted. The subjects breathed normally, in different postures, while thoracic movements were recorded so as to monitor respiration. A correlate of respiration was found in the time variation of DPOAE phase, with an estimated mean amplitude of 10 degrees , i.e. 60mm water, suggesting little attenuation across the aqueduct. Its phase lag relative to thoracic movements varied between 0 degrees and -270 degrees . When fed into a two-compartment model of CSF and labyrinthine spaces, these results suggest that respiration rate at rest is just above the resonance frequency of the CSF compartment, and just below the corner frequency of the cochlear-aqueduct low-pass filter, in line with previous estimates from temporal bone and intracranial measurements. The fact that infrasonic CSF waves can be monitored through the cochlea opens diagnostic possibilities in neurology.

4-aminopyridine in scala media reversibly alters the cochlear potentials and suppresses electrically evoked oto-acoustic emissions.

PubMed

Kirk, D L; Yates, G K

1998-01-01

Iontophoresis of 4-aminopyridine into scala media of the guinea pig cochlea caused elevation of the thresholds of the compound action potential of the auditory nerve, loss of amplitude of the extracellular cochlear microphonic response (CM), increase in the endocochlear potential (EP) and reduction in the amplitude of electrically evoked oto-acoustic emissions (EEOAEs). These changes were reversible over 10-20 min. The reciprocity of the changes in the CM and the EP was consistent with an interruption of both DC and AC currents through outer hair cells (OHCs), probably by blockade of mechano-electrical transduction (MET) channels in OHCs. Reductions in EEOAEs were consistent with the extrinsically applied generating current entering the OHC via the MET channels. Implications for the activation of OHC electromotility in vivo are discussed.

Level dependence of distortion product otoacoustic emissions in the leopard frog, Rana pipiens pipiens.

PubMed

Meenderink, Sebastiaan W F; van Dijk, Pim

2004-06-01

The inner ear of frogs holds two papillae specialized in detecting airborne sound, the amphibian papilla (AP) and the basilar papilla (BP). We measured input-output (I/O) curves of distortion product otoacoustic emissions (DPOAEs) from both papillae, and compared their properties. As in other vertebrates, DPOAE I/O curves showed two distinct segments, separated by a notch or kneepoint. The slope of the low-level segment was conspicuously different between the AP and the BP. For DPOAE I/O curves from the AP, slopes were < or = 1 dB/dB, similar to what is found in mammals, birds and some lizards. For DPOAE I/O curves from the BP these slopes were much steeper (approximately 2 dB/dB). Slopes found at high stimulus levels were similar in the AP and the BP (approximately 2 dB/dB). This quantitative difference between the low-level slopes for DPOAEs from the AP and the BP may signify the involvement of different mechanisms in low-level DPOAE generation for the two papillae, respectively.

Utility of Otoacoustic Emissions and Olivocochlear Reflex in Predicting Vulnerability to Noise-Induced Inner Ear Damage

PubMed Central

Blioskas, Sarantis; Tsalighopoulos, Miltiadis; Psillas, George; Markou, Konstantinos

2018-01-01

Aim: The aim of the present study was to explore the possible utility of otoacoustic emissions (OAEs) and efferent system strength to determine vulnerability to noise exposure in a clinical setting. Materials and Methods: The study group comprised 344 volunteers who had just begun mandatory basic training as Hellenic Corps Officers Military Academy cadets. Pure-tone audiograms were obtained on both ears. Participants were also subjected to diagnostic transient-evoked otoacoustic emissions (TEOAEs). Finally, they were all tested for efferent function through the suppression of TEOAEs with contralateral noise. Following baseline evaluation, all cadets fired 10 rounds using a 7.62 mm Heckler & Koch G3A3 assault rifle while lying down in prone position. Immediately after exposure to gunfire noise and no later than 10 h, all participants completed an identical protocol for a second time, which was then repeated a third time, 30 days later. Results: The data showed that after the firing drill, 280 participants suffered a temporary threshold shift (TTS) (468 ears), while in the third evaluation conducted 30 days after exposure, 142 of these ears still presented a threshold shift compared to the baseline evaluation [permanent threshold shift (PTS) ears]. A receiver operating characteristics curve analysis showed that OAEs amplitude is predictive of future TTS and PTS. The results were slightly different for the suppression of OAEs showing only a slight trend toward significance. The curves were used to determine cut points to evaluate the likelihood of TTS/PTS for OAEs amplitude in the baseline evaluation. Decision limits yielding 71.6% sensitivity were 12.45 dB SPL with 63.8% specificity for PTS, and 50% sensitivity were 12.35 dB SPL with 68.2% specificity for TTS. Conclusions: Interestingly, the above data yielded tentative evidence to suggest that OAEs amplitude is both sensitive and specific enough to efficiently identify participants who are particularly

Optimizing otoacoustic emission protocols for a UNHS program.

PubMed

Hatzopoulos, S; Petruccelli, J; Ciorba, A; Martini, A

2009-01-01

To identify the optimal test protocol to screen for hearing problems in newborns, an evaluation of three distortion product otoacoustic emission (DPOAE) protocols was conducted in neonates, from a well-baby nursery (WBN) and from a neonatal intensive care unit (NICU) and compared to the performance in newborns of a more standard protocol based on transient-evoked OAEs (TEOAEs). The DPOAE protocols used asymmetrical stimulus intensities (L(1) > L(2)) with a frequency ratio of 1.22, in the following format: (P1), L(1) = 60, L(2) = 50 dB SPL; (P2), L(1) = 65, L(2) = 55 dB SPL, and (P3), L(1) = 75, L(2) = 65 dB SPL. Linear TEOAE responses, evoked by click stimuli of 75 dB peSPL, were used as controls of normal cochlear function. Five frequencies at 1.5, 2.0, 3.0, 4.0 and 5.0 kHz were tested with a common commercially available macro-based software subroutine (Otodynamics Corp, ILO-92). The project evaluated the responses from 1200 WBN infants (average age 48 h) and 350 low-birth-weight NICU infants, all randomly selected. Statistical analyses comparing the signal-to-noise ratios (S/N), at the predefined f(2) frequencies, indicated that the P1 and P2 DPOAE protocols generated similar responses. Significant S/N differences were observed in the P3 to P2 dataset comparisons. DPOAE scoring criteria were estimated from the P3 dataset using a one-sided, distribution-free confidence intervals. The scoring criteria for a 'pass' were estimated as a minimum S/N of 6.0, 7.0 and 6.0 dB at 2.0, 3.0 and 4.0 kHz, respectively. In terms of feasibility, the P3 protocol generated responses in 98% of the WBN and 94.8% of the NICU infants. All three DPOAE protocols demonstrated shorter time-recording requirements than the standard TEOAE test. The false-positive and false-negative rates for the NICU infants were estimated as 0.0028 and 0.003%, respectively.

Evaluation of cochlear involvement by transient evoked otoacoustic emission test in children with Crimean-Congo hemorrhagic fever.

PubMed

Uysal, İsmail Önder; Kaya, Ali; Güven, Ahmet Sami; Altuntaş, Emine Elif; Müderris, Suphi

2011-06-01

The aim of this study was to investigate cochlear involvement in child patients with Crimean-Congo hemorrhagic fever (CCHF) disease. Twenty-eight CCHF disease patients (56 ears) and 26 sex- and age-matched healthy control subjects (52 ears) were included in the study. Pure-tone audiometry at frequencies 0.25, 0.5, 1, 2, 4, and 6 kHz, immittance measures including tympanometry and acoustic reflex testing, and transient evoked otoacoustic emission (TEOAE) testing were performed in the patients and controls. The proportion with a result of 'fail' for the TEOAE test in the CCHF patients was not statistically significant from the control group (p>0.05). CCHF disease does not impair cochlear function in children. The clinical course of CCHF among children seems to be milder than in adults. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

The influence of probe level on the tuning of stimulus frequency otoacoustic emissions and behavioral test in human.

PubMed

Wang, Yao; Gong, Qin; Zhang, Tao

2016-05-10

Frequency selectivity (FS) of the auditory system is established at the level of the cochlea and it is important for the perception of complex sounds. Although direct measurements of cochlear FS require surgical preparation, it can also be estimated with the measurements of otoacoustic emissions or behavioral tests, including stimulus frequency otoacoustic emission suppression tuning curves (SFOAE STCs) or psychophysical tuning curves (PTCs). These two methods result in similar estimates of FS at low probe levels. As the compressive nonlinearity of cochlea is strongly dependent on the stimulus intensity, the sharpness of tuning curves which is relevant to the cochlear nonlinearity will change as a function of probe level. The present study aims to investigate the influence of different probe levels on the relationship between SFOAE STCs and PTCs. The study included 15 young subjects with normal hearing. SFOAE STCs and PTCs were recorded at low and moderate probe levels for frequencies centred at 1, 2, and 4 kHz. The ratio or the difference of the characteristic parameters between the two methods was calculated at each probe level. The effect of probe level on the ratio or the difference between the parameters of SFOAE STCs and PTCs was then statistically analysed. The tuning of SFOAE STCs was significantly positively correlated with the tuning of the PTCs at both low and moderate probe levels; yet, at the moderate probe level, the SFOAE STCs were consistently broader than the PTCs. The mean ratio of sharpness of tuning at low probe levels was constantly around 1 while around 1.5 at moderate probe levels. Probe level had a significant effect on the sharpness of tuning between the two methods of estimating FS. SFOAE STC seems a good alternative measurement of PTC for FS assessment at low probe levels. At moderate probe levels, SFOAE STC and PTC were not equivalent measures of the FS in terms of their bandwidths. Because SFOAE STCs are not biased by higher levels

Contralateral Noise Stimulation Delays P300 Latency in School-Aged Children.

PubMed

Ubiali, Thalita; Sanfins, Milaine Dominici; Borges, Leticia Reis; Colella-Santos, Maria Francisca

2016-01-01

The auditory cortex modulates auditory afferents through the olivocochlear system, which innervates the outer hair cells and the afferent neurons under the inner hair cells in the cochlea. Most of the studies that investigated the efferent activity in humans focused on evaluating the suppression of the otoacoustic emissions by stimulating the contralateral ear with noise, which assesses the activation of the medial olivocochlear bundle. The neurophysiology and the mechanisms involving efferent activity on higher regions of the auditory pathway, however, are still unknown. Also, the lack of studies investigating the effects of noise on human auditory cortex, especially in peadiatric population, points to the need for recording the late auditory potentials in noise conditions. Assessing the auditory efferents in schoolaged children is highly important due to some of its attributed functions such as selective attention and signal detection in noise, which are important abilities related to the development of language and academic skills. For this reason, the aim of the present study was to evaluate the effects of noise on P300 responses of children with normal hearing. P300 was recorded in 27 children aged from 8 to 14 years with normal hearing in two conditions: with and whitout contralateral white noise stimulation. P300 latencies were significantly longer at the presence of contralateral noise. No significant changes were observed for the amplitude values. Contralateral white noise stimulation delayed P300 latency in a group of school-aged children with normal hearing. These results suggest a possible influence of the medial olivocochlear activation on P300 responses under noise condition.

Changes in transient-evoked otoacoustic emission levels with negative tympanometric peak pressure in infants and toddlers.

PubMed

Prieve, Beth A; Calandruccio, Lauren; Fitzgerald, Tracy; Mazevski, Annette; Georgantas, Lea M

2008-08-01

Otoacoustic emission (OAE) testing is now a standard component of the diagnostic audiology protocol for infants and toddlers and is an excellent tool for detecting moderate-to-profound cochlear hearing loss. Detection of hearing loss is especially important in infants and toddlers. Unfortunately, middle-ear dysfunction has a high incidence in this age range and can confound interpretation of OAEs. The goal of the study was to determine how transient-evoked otoacoustic emission (TEOAE) and noise levels were different when tympanometric peak pressures (TPP) measured from tympanograms were normal versus negative in the same individual. Another goal was to determine how TEOAE screening pass rates using a priori pass criteria were affected on days when TPP was negative. TEOAE and noise levels were collected in 18 cases under 2 conditions: on a day when the tympanogram TPP was normal and on a day when the tympanogram TPP was negative. Data were collected from 11 children aged 3 to 39 mo, some of whom were tested more than once. Paired t tests were performed to determine whether there were changes in overall TEOAE and noise levels and TEOAE and noise levels analyzed into half-octave bands. A one-way ANOVA was performed on differences across half-octave bands to determine whether TPP affected TEOAE levels for some frequency bands more than others. Equality-of-proportion Z tests were run to determine whether there were significant differences in the percentage of "passes" on days when TPP was negative and TPP was normal. Mean TEOAE level was lower when TPP was negative, but noise levels did not change between the 2 conditions. Mean TEOAE levels were lower for all frequency bands from 1000 to 4000 Hz and no significant differences were found among the mean reduction across frequency bands. There were no significant differences in the percentage of passes between TEOAEs collected on days when TPP was normal and when TPP was negative. Mean data indicated that when tympanograms

Growth of suppression in humans based on distortion-product otoacoustic emission measurements

PubMed Central

Gorga, Michael P.; Neely, Stephen T.; Kopun, Judy; Tan, Hongyang

2011-01-01

Distortion-product otoacoustic emissions (DPOAEs) were used to describe suppression growth in normal-hearing humans. Data were collected at eight f2 frequencies ranging from 0.5 to 8 kHz for L2 levels ranging from 10 to 60 dB sensation level. For each f2 and L2 combination, suppression was measured for nine or eleven suppressor frequencies (f3) whose levels varied from −20 to 85 dB sound pressure level (SPL). Suppression grew nearly linearly when f3 ≈ f2, grew more rapidly for f3 < f2, and grew more slowly for f3 > f2. These results are consistent with physiological and mechanical data from lower animals, as well as previous DPOAE data from humans, although no previous DPOAE study has described suppression growth for as wide a range of frequencies and levels. These trends were evident for all f2 and L2 combinations; however, some exceptions were noted. Specifically, suppression growth rate was less steep as a function of f3 for f2 frequencies ≤1 kHz. Thus, despite the qualitative similarities across frequency, there were quantitative differences related to f2, suggesting that there may be subtle differences in suppression for frequencies above 1 kHz compared to frequencies below 1 kHz. PMID:21361439

Low-frequency and high-frequency distortion product otoacoustic emission suppression in humans

PubMed Central

Gorga, Michael P.; Neely, Stephen T.; Dierking, Darcia M.; Kopun, Judy; Jolkowski, Kristin; Groenenboom, Kristin; Tan, Hongyang; Stiegemann, Bettina

2008-01-01

Distortion product otoacoustic emission suppression (quantified as decrements) was measured for f2=500 and 4000 Hz, for a range of primary levels (L2), suppressor frequencies (f3), and suppressor levels (L3) in 19 normal-hearing subjects. Slopes of decrement-versus-L3 functions were similar at both f2 frequencies, and decreased as f3 increased. Suppression tuning curves, constructed from decrement functions, were used to estimate (1) suppression for on- and low-frequency suppressors, (2) tip-to-tail differences, (3) QERB, and (4) best frequency. Compression, estimated from the slope of functions relating suppression “threshold” to L2 for off-frequency suppressors, was similar for 500 and 4000 Hz. Tip-to-tail differences, QERB, and best frequency decreased as L2 increased for both frequencies. However, tip-to-tail difference (an estimate of cochlear-amplifier gain) was 20 dB greater at 4000 Hz, compared to 500 Hz. QERB decreased to a greater extent with L2 when f2=4000 Hz, but, on an octave scale, best frequency shifted more with level when f2=500 Hz. These data indicate that, at both frequencies, cochlear processing is nonlinear. Response growth and compression are similar at the two frequencies, but gain is greater at 4000 Hz and spread of excitation is greater at 500 Hz. PMID:18397024

Chronic excitotoxicity in the guinea pig cochlea induces temporary functional deficits without disrupting otoacoustic emissions

NASA Astrophysics Data System (ADS)

Le Prell, Colleen G.; Yagi, Masao; Kawamoto, Kohei; Beyer, Lisa A.; Atkin, Graham; Raphael, Yehoash; Dolan, David F.; Bledsoe, Sanford C.; Moody, David B.

2004-08-01

Brief cochlear excitotoxicity produces temporary neural swelling and transient deficits in auditory sensitivity; however, the consequences of long-lasting excitotoxic insult have not been tested. Chronic intra-cochlear infusion of the glutamate agonist AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) resulted in functional deficits in the sound-evoked auditory brainstem response, as well as in behavioral measures of hearing. The electrophysiological deficits were similar to those observed following acute infusion of AMPA into the cochlea; however, the concentration-response curve was significantly shifted as a consequence of the slower infusion rate used with chronic cochlear administration. As observed following acute excitotoxic insult, complete functional recovery was evident within 7 days of discontinuing the AMPA infusion. Distortion product otoacoustic emissions were not affected by chronic AMPA infusion, suggesting that trauma to outer hair cells did not contribute to AMPA-induced deficits in acoustic sensitivity. Results from the current experiment address the permanence of deficits induced by chronic (14 day) excitotoxic insult as well as deficits in psychophysical detection of longer duration acoustic signals.

Contralateral acoustic stimulation alters the magnitude and phase of distortion product otoacoustic emissions.

PubMed

Deeter, Ryan; Abel, Rebekah; Calandruccio, Lauren; Dhar, Sumitrajit

2009-11-01

Activation of medial olivocochlear efferents through contralateral acoustic stimulation (CAS) has been shown to modulate distortion product otoacoustic emission (DPOAE) level in various ways (enhancement, reduction, or no change). The goal of this study was to investigate the effect of a range of CAS levels on DPOAE fine structure. The 2f(1)-f(2) DPOAE was recorded (f(2)/f(1)=1.22, L(1)=55 dB, and L(2)=40 dB) from eight normal-hearing subjects, using both a frequency-sweep paradigm and a fixed frequency paradigm. Contamination due to the middle ear muscle reflex was avoided by monitoring the magnitude and phase of a probe in the test ear and by monitoring DPOAE stimulus levels throughout testing. Results show modulations in both level and frequency of DPOAE fine structure patterns. Frequency shifts observed at DPOAE level minima could explain reports of enhancement in DPOAE level due to efferent activation. CAS affected the magnitude and phase of the DPOAE component from the characteristic frequency region to a greater extent than the component from the overlap region between the stimulus tones. This differential effect explains the occasional enhancement observed in DPOAE level as well as the frequency shift in fine structure patterns.

Level dependence of distortion product otoacoustic emission phase is attributed to component mixing

PubMed Central

Abdala, Carolina; Dhar, Sumitrajit; Kalluri, Radha

2011-01-01

Distortion product otoacoustic emissions (DPOAEs) measured in the ear canal represent the vector sum of components produced at two regions of the basilar membrane by distinct cochlear mechanisms. In this study, the effect of stimulus level on the 2f1 − f2 DPOAE phase was evaluated in 22 adult subjects across a three-octave range. Level effects were examined for the mixed DPOAE signal measured in the ear canal and after unmixing components to assess level effects individually on the distortion (generated at the f1, f2 overlap) and reflection (at fdp) sources. Results show that ear canal DPOAE phase slope becomes steeper with decreasing level; however, component analysis further explicates this result, indicating that interference between DPOAE components (rather than a shift in mechanics related to distortion generation) drives the level dependence of DPOAE phase measured in the ear canal. The relative contribution from the reflection source increased with decreasing level, producing more component interference and, at times, a reflection-dominated response at the lowest stimulus levels. These results have implications for the use of DPOAE phase to study cochlear mechanics and for the potential application of DPOAE phase for clinical purposes. PMID:21568415

On reliable time-frequency characterization and delay estimation of stimulus frequency otoacoustic emissions

NASA Astrophysics Data System (ADS)

Biswal, Milan; Mishra, Srikanta

2018-05-01

The limited information on origin and nature of stimulus frequency otoacoustic emissions (SFOAEs) necessitates a thorough reexamination into SFOAE analysis procedures. This will lead to a better understanding of the generation of SFOAEs. The SFOAE response waveform in the time domain can be interpreted as a summation of amplitude modulated and frequency modulated component waveforms. The efficiency of a technique to segregate these components is critical to describe the nature of SFOAEs. Recent advancements in robust time-frequency analysis algorithms have staked claims on the more accurate extraction of these components, from composite signals buried in noise. However, their potential has not been fully explored for SFOAEs analysis. Indifference to distinct information, due to nature of these analysis techniques, may impact the scientific conclusions. This paper attempts to bridge this gap in literature by evaluating the performance of three linear time-frequency analysis algorithms: short-time Fourier transform (STFT), continuous Wavelet transform (CWT), S-transform (ST) and two nonlinear algorithms: Hilbert-Huang Transform (HHT), synchrosqueezed Wavelet transform (SWT). We revisit the extraction of constituent components and estimation of their magnitude and delay, by carefully evaluating the impact of variation in analysis parameters. The performance of HHT and SWT from the perspective of time-frequency filtering and delay estimation were found to be relatively less efficient for analyzing SFOAEs. The intrinsic mode functions of HHT does not completely characterize the reflection components and hence IMF based filtering alone, is not recommended for segregating principal emission from multiple reflection components. We found STFT, WT, and ST to be suitable for canceling multiple internal reflection components with marginal altering in SFOAE.

Reliability of measures of transient evoked otoacoustic emissions with contralateral suppression.

PubMed

Stuart, Andrew; Cobb, Kensi M

2015-01-01

The reliability of measures of transient evoked otoacoustic emissions (TEOAEs) with contralateral suppression was examined. The effect of test session (i.e., initial test; retest without probe removal; retest with probe removal; and retest 1-2 days post initial test), gender, and ear was examined in 14 young adult females and 14 young adult males. TEOAEs were obtained bilaterally with 60 dB peSPL linear click stimuli with and without a contralateral 65 dB SPL broadband noise suppressor. Absolute TEOAE suppression and a normalized index of TEOAE suppression (i.e., percentage of suppression) were examined. Reliability of these measures was assessed with repeated measures linear mixed model analysis of variance, a coefficient of reliability, and Bland-Altman analyses. There were no statistically significant (p>0.05) main effects of test, gender, and ear or interactions for both absolute dB and % TEOAE suppression values. Cronbach's α were greater than 0.90 across the four tests for both TEOAE measures. Mean test differences or bias (i.e., between the initial and subsequent tests) for absolute and % TEOAE suppression ranged from -0.05 to 0.11 dB and -1.5% to 1.1%, respectively. There was no proportional/systematic bias with the mean differences of the first and subsequent measurements. Data herein were consistent with the view that bilateral TEOAE suppression measures are reliable across test sessions of 1-2 days among females and males and may provide a method to monitor medial olivocochlear efferent reflex status over time. Copyright © 2015 Elsevier Inc. All rights reserved.

Moments of click-evoked otoacoustic emissions in human ears: group delay and spread, instantaneous frequency and bandwidth.

PubMed

Keefe, Douglas H

2012-11-01

A click-evoked otoacoustic emission (CEOAE) has group delay and spread as first- and second-order temporal moments varying over frequency, and instantaneous frequency and bandwidth as first- and second-order spectral moments varying over time. Energy-smoothed moments were calculated from a CEOAE database over 0.5-15 kHz bandwidth and 0.25-20 ms duration. Group delay and instantaneous frequency were calculated without phase unwrapping using a coherence synchrony measure that accurately classified ears with hearing loss. CEOAE moment measurements were repeatable in individual ears. Group delays were similar for CEOAEs and stimulus-frequency OAEs. Group spread is a frequency-specific measure of temporal spread in an emission, related to spatial spread across tonotopic generation sites along the cochlea. In normal ears, group delay and spread increased with frequency and decreased with level. A direct measure of cochlear tuning above 4 kHz was analyzed using instantaneous frequency and bandwidth. Synchronized spontaneous OAEs were present in most ears below 4 kHz, and confounded interpretation of moments. In ears with sensorineural hearing loss, group delay and spread varied with audiometric classification and amount of hearing loss; group delay differed between older males and females. CEOAE moments reveal clinically relevant information on cochlear tuning in ears with normal and impaired hearing.

Stability of the Medial Olivocochlear Reflex as Measured by Distortion Product Otoacoustic Emissions

PubMed Central

Abdala, Carolina

2015-01-01

Purpose The purpose of this study was to assess the repeatability of a fine-resolution, distortion product otoacoustic emission (DPOAE)–based assay of the medial olivocochlear (MOC) reflex in normal-hearing adults. Method Data were collected during 36 test sessions from 4 normal-hearing adults to assess short-term stability and 5 normal-hearing adults to assess long-term stability. DPOAE level and phase measurements were recorded with and without contralateral acoustic stimulation. MOC reflex indices were computed by (a) noting contralateral acoustic stimulation-induced changes in DPOAE level (both absolute and normalized) at fine-structure peaks, (b) recording the effect as a vector difference, and (c) separating DPOAE components and considering a component-specific metric. Results Analyses indicated good repeatability of all indices of the MOC reflex in most frequency ranges. Short- and long-term repeatability were generally comparable. Indices normalized to a subject's own baseline fared best, showing strong short- and long-term stability across all frequency intervals. Conclusions These results suggest that fine-resolution DPOAE-based measures of the MOC reflex measured at strategic frequencies are stable, and natural variance from day-to-day or week-to-week durations is small enough to detect between-group differences and possibly to monitor intervention-related success. However, this is an empirical question that must be directly tested to confirm its utility. PMID:25320951

Dichotic listening and otoacoustic emissions: shared variance between cochlear function and dichotic listening performance in adults with normal hearing.

PubMed

Markevych, Vladlena; Asbjørnsen, Arve E; Lind, Ola; Plante, Elena; Cone, Barbara

2011-07-01

The present study investigated a possible connection between speech processing and cochlear function. Twenty-two subjects with age range from 18 to 39, balanced for gender with normal hearing and without any known neurological condition, were tested with the dichotic listening (DL) test, in which listeners were asked to identify CV-syllables in a nonforced, and also attention-right, and attention-left condition. Transient evoked otoacoustic emissions (TEOAEs) were recorded for both ears, with and without the presentation of contralateral broadband noise. The main finding was a strong negative correlation between language laterality as measured with the dichotic listening task and of the TEOAE responses. The findings support a hypothesis of shared variance between central and peripheral auditory lateralities, and contribute to the attentional theory of auditory lateralization. The results have implications for the understanding of the cortico-fugal efferent control of cochlear activity. 2011 Elsevier Inc. All rights reserved.

Effects of Middle Ear Pressure on Otoacoustic Emission Measures.

NASA Astrophysics Data System (ADS)

Zhang, Ming

1995-01-01

Otoacoustic emissions (OAEs) are used extensively in hearing evaluations. Changes in middle ear pressure may have an effect on both forward and backward transmission of signals through the middle ear. The effect that such changes have on OAEs may depend on extent of pressure change, stimulus frequency, and stimulus level. This study quantitatively evaluates the effects of these variables on distortion product OAEs (DPOAEs) and cochlear microphonic distortion products (CMDPs) for a wide range of stimuli. Pigmented adult guinea pigs were experimental subjects. An animal surgical model was established to manipulate pressure in the middle ear and CMDP and DPOAE were simultaneously measured. The effects on forward transmission were determined from the CMDP data. It was assumed that the DPOAE measures were affected by changes in both forward and backward transmission. The effects on backward transmission were determined from the DPOAE data after the effect on forward transmission were subtracted out. For all conditions the frequency ratio rm f_2/f_1 was held at 1.2 and the level ratio rm L_1/L_2 was 10 dB. The effects on forward transmission were similar to those for backward transmission in all experimental conditions. Negative pressure had a greater effect than positive pressure. Positive pressures of +10 and +20 cmH_2O affected transmission for low frequency stimuli (f_2 = 1620 and 2680 Hz) but had little effect for high frequency stimuli (f_2 = 6980 and 10250 Hz). Negative pressures of -2.5 to -10 cmH_2O affected transmission across all frequencies tested. The effect at low frequencies is hypothesized to be related to tympanic membrane stiffness. The effect of negative pressure at high frequencies may be related to change in the incudostapedial joint. The slope of growth function decreased with the pressure change for DPOAEs but changed little for CMDPs. The decrease in slope for DPOAEs suggests that the level chosen for analysis can influence the result of the

Distortion product otoacoustic emissions in college music majors and nonmusic majors

PubMed Central

Henning, Rebecca L. Warner; Bobholz, Kate

2016-01-01

The presence and absence of distortion product otoacoustic emissions (DPOAEs) as well as DPOAE amplitudes were compared between college music majors and a control group of nonmusic majors. Participants included 28 music majors and 35 nonmusic majors enrolled at a university with ages ranging from 18-25 years. DPOAEs and hearing thresholds were measured bilaterally on all the participants. DPOAE amplitudes were analyzed at the following f2 frequencies: 1,187 Hz, 1,500 Hz, 1,906 Hz, 2,531 Hz, 3,031 Hz, 3812 Hz, 4,812 Hz, and 6,031 Hz. Significantly more music majors (7/28) than nonmusic majors (0/35) exhibited absent DPOAEs for at least one frequency in at least one ear. Both groups of students reported similar histories of recreational and occupational noise exposures that were unrelated to studying music, and none of the students reported high levels of noise exposure within the previous 48 h. There were no differences in audiometric thresholds between the groups at any frequency. At DPOAE f2 frequencies from 3,031 Hz to 6,031 Hz, nonsignificantly lower amplitudes of 2-4 dB were seen in the right ears of music majors versus nonmajors, and in the right ears of music majors playing brass instruments compared to music majors playing nonbrass instruments. Given the greater prevalence of absent DPOAEs in university music majors compared to nonmusic majors, it appears that early stages of cochlear damage may be occurring in this population. Additional research, preferably longitudinal and across multiple colleges/universities, would be beneficial to more definitively determine when the music students begin to show signs of cochlear damage, and to identify whether any particular subgroups of music majors are at a greater risk of cochlear damage. PMID:26780957

Distortion product otoacoustic emissions in college music majors and nonmusic majors.

PubMed

Henning, Rebecca L Warner; Bobholz, Kate

2016-01-01

The presence and absence of distortion product otoacoustic emissions (DPOAEs) as well as DPOAE amplitudes were compared between college music majors and a control group of nonmusic majors. Participants included 28 music majors and 35 nonmusic majors enrolled at a university with ages ranging from 18-25 years. DPOAEs and hearing thresholds were measured bilaterally on all the participants. DPOAE amplitudes were analyzed at the following f2 frequencies: 1,187 Hz, 1,500 Hz, 1,906 Hz, 2,531 Hz, 3,031 Hz, 3812 Hz, 4,812 Hz, and 6,031 Hz. Significantly more music majors (7/28) than nonmusic majors (0/35) exhibited absent DPOAEs for at least one frequency in at least one ear. Both groups of students reported similar histories of recreational and occupational noise exposures that were unrelated to studying music, and none of the students reported high levels of noise exposure within the previous 48 h. There were no differences in audiometric thresholds between the groups at any frequency. At DPOAE f2 frequencies from 3,031 Hz to 6,031 Hz, nonsignificantly lower amplitudes of 2-4 dB were seen in the right ears of music majors versus nonmajors, and in the right ears of music majors playing brass instruments compared to music majors playing nonbrass instruments. Given the greater prevalence of absent DPOAEs in university music majors compared to nonmusic majors, it appears that early stages of cochlear damage may be occurring in this population. Additional research, preferably longitudinal and across multiple colleges/universities, would be beneficial to more definitively determine when the music students begin to show signs of cochlear damage, and to identify whether any particular subgroups of music majors are at a greater risk of cochlear damage.

Evidence for a bipolar change in distortion product otoacoustic emissions during contralateral acoustic stimulation in humans

NASA Astrophysics Data System (ADS)

Müller, Jörg; Janssen, Thomas; Heppelmann, Guido; Wagner, Wolfgang

2005-12-01

The aim of this study was to investigate the activity of the medial olivocochlear (MOC) efferents during contralateral (CAS) and ipsilateral acoustic stimulation (IAS) by recording distortion product otoacoustic emission (DPOAE) suppression and DPOAE adaptation in humans. The main question was: do large bipolar changes in DPOAE level (transition from enhancement to suppression) also occur in humans when changing the primary tone level within a small range as described by Maison and Liberman for guinea pigs [J. Neurosci. 20, 4701-4707 (2000)]? In the present study, large bipolar changes in DPOAE level (14 dB on average across subjects) were found during CAS predominantly at frequencies where dips in the DPOAE fine structure occurred. Thus, effects of the second DPOAE source might be responsible for the observed bipolar effect. In contrast, comparable effects were not found during IAS as was reported in guinea pigs. Reproducibility of CAS DPOAEs was better than that for IAS DPOAEs. Thus, contralateral DPOAE suppression is suggested to be superior to ipsilateral DPOAE adaptation with regard to measuring the MOC reflex strength and for evaluating the vulnerability of the cochlea to acoustic overexposure in a clinical context.

Otoacoustic emission estimates of human basilar membrane impulse response duration and cochlear filter tuning.

PubMed

Raufer, Stefan; Verhulst, Sarah

2016-12-01

This study describes a method based on temporal suppression of click-evoked otoacoustic emissions (CEOAEs) to estimate the time course and duration of human basilar membrane impulse responses (BM IRs). This was achieved by tracing the suppression of dominant peaks in the CEOAE spectrum as a function of the temporal separation between two equal-level stimulus clicks. The relationship between the suppression pattern and underlying BM IR duration near the generation site of the CEOAE frequency was established using model simulations. To relate BM IR duration estimates to cochlear filter tuning (Q ERB ), a tuning ratio was derived from available BM IR measurements in animals. Results for 11 normal-hearing subjects yielded BM IR duration estimates of 37.4/F ms at 65 dB peSPL and 36.4/F ms at 71 dB peSPL, with F in kHz. Corresponding Q ERB estimates were 14.2F[in kHz] 0.22 at 65 dB peSPL and 13.8F[in kHz] 0.22 at 71 dB peSPL. Because the proposed temporal suppression method relies on cochlear nonlinearity, the method is applicable for stimulus levels above 30-40 dB SPL and complements existing OAE methods to assess human cochlear filter tuning. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of extremely low frequency electromagnetic fields on distortion product otoacoustic emissions in rabbits.

PubMed

Budak, Bilgehan; Budak, Gürer G; Oztürk, Göknur Güler; Muluk, Nuray Bayar; Apan, Alpaslan; Seyhan, Nesrin

2009-06-01

Humans are continuously exposed to extremely low frequency (ELF), electromagnetic fields (EMF), transmitted from the common sources like power stations, electric transmission lines, communication and radio-television signal transmission units. The present study aimed to assess the effects of 50 Hz ELF-EMF of 5.068 and 10.182 kV/m electric fields, which refer to the lower and upper intensity limits beyond which hazardous effects can be observed, on the auditory functions of rabbits via Distortion Product Otoacoustic Emission (DPOAE) recordings. The study was performed on 20 healthy adult female New Zealand White rabbits randomly divided into two groups and applied 50 Hz ELF-EMF with either 5.068 kV/m (Group 1) or 10.182 kV/m (Group 2) of electric field for 3h/day during 14 days. DPOAE responses recorded on the 0th day before exposure (B-EMF) and on the 6th (A-EMF-6th) and 14th (A-EMF-14th) days after exposure (AE). Mean stimulus intensity and emission amplitudes at 1.0-8.0 kHz were analyzed. In Group 2 rabbits, on 6th and 14th days, the DPOAE amplitudes were observed as increased at 1.5-4.0 kHz (at 2.0 and 4.0 kHz significantly) than B-EMF values. At 6.0 kHz, A-EMF-14th amplitudes were significantly lower than A-EMF values. These results suggest that ELF EMFs might affect hearing functions by frequency dependent manner. Higher ELF EMFs exposure caused increase of cochlear activity. Ototoxic effect of 10.182 kV/m ELF EMFs may begin at the basal turn of the cochlea by reducing DPOAEs at high frequencies.

Otoacoustic emissions in the general adult population of Nord-Trøndelag, Norway: III. Relationships with pure-tone hearing thresholds.

PubMed

Engdahl, Bo; Tambs, Kristian; Borchgrevink, Hans M; Hoffman, Howard J

2005-01-01

This study aims to describe the association between otoacoustic emissions (OAEs) and pure-tone hearing thresholds (PTTs) in an unscreened adult population (N =6415), to determine the efficiency by which TEOAEs and DPOAEs can identify ears with elevated PTTs, and to investigate whether a combination of DPOAE and TEOAE responses improves this performance. Associations were examined by linear regression analysis and ANOVA. Test performance was assessed by receiver operator characteristic (ROC) curves. The relation between OAEs and PTTs appeared curvilinear with a moderate degree of non-linearity. Combining DPOAEs and TEOAEs improved performance. Test performance depended on the cut-off thresholds defining elevated PTTs with optimal values between 25 and 45 dB HL, depending on frequency and type of OAE measure. The unique constitution of the present large sample, which reflects the general adult population, makes these results applicable to population-based studies and screening programs.

Otoacoustic emissions versus audiometry in monitoring hearing loss after long-term noise exposure - a systematic review.

PubMed

Helleman, Hiske W; Eising, Hilde; Limpens, Jacqueline; Dreschler, Wouter A

2018-03-15

Objectives The objective of this systematic review was to compare otoacoustic emissions (OAE) with audiometry in their effectiveness to monitor effects of long-term noise exposure on hearing. Methods We conducted a systematic search of MEDLINE, Embase and the non-MEDLINE subset of PubMed up to March 2016 to identify longitudinal studies on effects of noise exposure on hearing as determined by both audiometry and OAE. Results This review comprised 13 articles, with 30-350 subjects in the longitudinal analysis. A meta-analysis could not be performed because the studies were very heterogeneous in terms of measurement paradigms, follow-up time, age of included subjects, inclusion of data points, outcome parameters and method of analysis. Overall there seemed to be small changes in both audiometry and OAE over time. Individual shifts were detected by both methods but a congruent pattern could not be observed. Some studies found that initial abnormal or low-level emissions might predict future hearing loss but at the cost of low specificity due to a high number of false positives. Other studies could not find such predictive value. Conclusions The reported heterogeneity in the studies calls for more uniformity in including, reporting and analyzing longitudinal data for audiometry and OAE. For the overall results, both methods showed small changes from baseline towards a deterioration in hearing. OAE could not reliably detect threshold shifts at individual level. With respect to the predictive value of OAE, the evidence was not conclusive and studies were not in agreement. The reported predictors had low specificity.

Emission of sound from the mammalian inner ear

NASA Astrophysics Data System (ADS)

Reichenbach, Tobias; Stefanovic, Aleksandra; Nin, Fumiaki; Hudspeth, A. J.

2013-03-01

The mammalian inner ear, or cochlea, not only acts as a detector of sound but can also produce tones itself. These otoacoustic emissions are a striking manifestation of the mechanical active process that sensitizes the cochlea and sharpens its frequency discrimination. It remains uncertain how these signals propagate back to the middle ear, from which they are emitted as sound. Although reverse propagation might occur through waves on the cochlear basilar membrane, experiments suggest the existence of a second component in otoacoustic emissions. We have combined theoretical and experimental studies to show that mechanical signals can also be transmitted by waves on Reissner's membrane, a second elastic structure within the cochea. We have developed a theoretical description of wave propagation on the parallel Reissner's and basilar membranes and its role in the emission of distortion products. By scanning laser interferometry we have measured traveling waves on Reissner's membrane in the gerbil, guinea pig, and chinchilla. The results accord with the theory and thus support a role for Reissner's membrane in otoacoustic emission. T. R. holds a Career Award at the Scientific Interface from the Burroughs Wellcome Fund; A. J. H. is an Investigator of Howard Hughes Medical Institute.

Tinnitus is associated with reduced sound level tolerance in adolescents with normal audiograms and otoacoustic emissions

PubMed Central

Sanchez, Tanit Ganz; Moraes, Fernanda; Casseb, Juliana; Cota, Jaci; Freire, Katya; Roberts, Larry E.

2016-01-01

Recent neuroscience research suggests that tinnitus may reflect synaptic loss in the cochlea that does not express in the audiogram but leads to neural changes in auditory pathways that reduce sound level tolerance (SLT). Adolescents (N = 170) completed a questionnaire addressing their prior experience with tinnitus, potentially risky listening habits, and sensitivity to ordinary sounds, followed by psychoacoustic measurements in a sound booth. Among all adolescents 54.7% reported by questionnaire that they had previously experienced tinnitus, while 28.8% heard tinnitus in the booth. Psychoacoustic properties of tinnitus measured in the sound booth corresponded with those of chronic adult tinnitus sufferers. Neither hearing thresholds (≤15 dB HL to 16 kHz) nor otoacoustic emissions discriminated between adolescents reporting or not reporting tinnitus in the sound booth, but loudness discomfort levels (a psychoacoustic measure of SLT) did so, averaging 11.3 dB lower in adolescents experiencing tinnitus in the acoustic chamber. Although risky listening habits were near universal, the teenagers experiencing tinnitus and reduced SLT tended to be more protective of their hearing. Tinnitus and reduced SLT could be early indications of a vulnerability to hidden synaptic injury that is prevalent among adolescents and expressed following exposure to high level environmental sounds. PMID:27265722

Distortion product otoacoustic emission suppression tuning and acoustic admittance in human infants: Birth through 6 months

PubMed Central

Abdala, Carolina; Keefe, Douglas H.; Oba, Sandra I.

2009-01-01

Previous work has reported non-adultlike distortion product otoacoustic emission (DPOAE) suppression in human newborns at f2 =6000 Hz, indicating an immaturity in peripheral auditory function. In this study, DPOAE suppression tuning curves (STCs) were recorded as a measure of cochlear function and acoustic admittance/reflectance (YR) in the ear canal recorded as a measure of middle-ear function, in the same 20 infants at birth and through 6 months of age. DPOAE STCs changed little from birth through 6 months, showing excessively narrow and sharp tuning throughout the test period. In contrast, several middle-ear indices at corresponding frequencies shifted systematically with increasing age, although they also remained non-adultlike at 6 months. Linear correlations were conducted between YR and DPOAE suppression features. Only two correlations out of 76 were significant, and all but three YR variables accounted for <10% of the variance in DPOAE suppression tuning. The strongest correlation was noted between admittance phase at 5700 Hz and STC tip-to-tail (R=0.49). The association between middle-ear variables and DPOAE suppression may be stronger during other developmental time periods. Study of older infants and children is needed to fully define postnatal immaturity of human peripheral auditory function. PMID:17552713

Enhancement of electrically evoked oto-acoustic emissions associated with low-frequency stimulus bias of the basilar membrane towards scala vestibuli.

PubMed

Kirk, D L; Yates, G K

1998-09-01

Electrically evoked oto-acoustic emissions (EEOAEs) are sounds present in the ear canal when ac current is passed into the cochlea. EEOAEs are attributed to the activation of fast electromotile responses in outer hair cells (OHCs). An interesting property of EEOAEs is the phenomenon of "acoustic enhancement," where the emission amplitude is increased by moderate-level sound [D. C. Mountain and A. E. Hubbard, Hear. Res. 42, 195-202 (1989)]. In this report a form of enhancement is described which occurs with displacements of the basilar membrane toward scala vestibuli, during amplitude modulation of the EEOAE waveform by low-frequency tones. This "SV-bias enhancement" possibly consists of two components: (i) a low-level component induced by sound at levels which produce nonlinear growth of the cochlear microphonic and which may be equivalent to the "acoustic enhancement" described previously, and (ii) a high-level component which occurs at sound levels well above those which cause saturation of the cochlear microphonic. The low-level component could be explained by either an increased access of the extrinsically applied current to a membrane-based source of OHC motility, perhaps coupled with a reduction in negative feedback, or an increase in electromotile output during scala vestibuli displacements, but the origin of the high-level component is obscure.

Gender, music, and distortion product otoacoustic emission components.

PubMed

Torre, Peter; Grace, Jennifer; Hansen, Christina; Millman, Paige; Martin, Hannah

2013-01-01

The prevalence of personal music (PM) system use with earphones is high among young adults. Although previous research has demonstrated that the majority of these adults may not be listening at levels or for durations considered dangerous, the long-term consequences of PM system use are not fully understood. In this report the relationship between self-reported PM use (i.e., non, light, moderate, or heavy) and peripheral auditory function as assayed through distortion product otoacoustic emission (DPOAE) components and fine structure was explored. The purpose was to evaluate the relationship between PM system use and peripheral auditory function. One hundred and one (N = 101) young adults, 18 to 30 years of age, with normal hearing. Survey data were first obtained to determine PM system user status along with type of earphones used, most common listening volume, and most common listening duration. Once normal-hearing sensitivity was confirmed with a hearing screening, the DPOAE research protocol was administered. DPOAEs (2f1 to f2) were measured between 1 and 6 kHz with stimulus levels fixed at L1, L2 = 55,40 dB SPL and f2/f1 = 1.22. DPOAE level as well as fine-structure depth and spacing in 1/3rd octave (oct) bands around 1, 1.5, 2, 3, 4, and 6 kHz were compared across various PM system user groups. The ear-canal DPOAE was separated into the so-called generator and characteristic frequency (CF) components. The characteristics of the components were also compared across user groups. Almost all participants reported listening to a PM system between < 1 hr/d to 3 hr/d, and 67% of the participants reported medium/comfortable as the most common volume used during a typical day. There was no significant effect of user status on 3rd oct DPOAE data, 1/3rd oct band component data, or fine-structure spacing data. Women exhibited significantly higher DPOAE as well as generator and CF component levels in the lower half of the frequency range evaluated. There were no

Otoacoustic Emissions in Rural Nicaragua: Cost Analysis and Implications for Newborn Hearing Screening.

PubMed

Wong, Lye-Yeng; Espinoza, Francisca; Alvarez, Karen Mojica; Molter, Dave; Saunders, James E

2017-05-01

Objective (1) Determine the incidence and risk factors for congenital hearing loss. (2) Perform cost analysis of screening programs. Study Design Proportionally distributed cross-sectional survey. Setting Jinotega, Nicaragua. Subjects and Methods Otoacoustic emissions (OAEs) were used to screen 640 infants <6 months of age from neonatal intensive care unit, institutional, and home birth settings. Data on 15 risk factors were analyzed. Cost of 4 implementation strategies was studied: universal screening, screening at the regional health center (RHC), targeted screening, and screening at the RHC plus targeted screening. Cost-effectiveness analysis over 10 years was based on disability-adjusted life year estimates, with the World Health Organization standard of cost-effectiveness ratio (CER) / gross domestic product (GDP) <3, with GDP set at $4884.15. Results Thirty-eight infants failed the initial OAE (5.94%). In terms of births, 325 (50.8%) were in the RHC, 69 (10.8%) in the neonatal intensive care unit, and 29 (4.5%) at home. Family history and birth defect were significant in univariate analysis; birth defect was significant in multivariate analysis. Cost-effectiveness analysis demonstrated that OAE screening is cost-effective without treatment (CER/GDP = 0.06-2.00) and with treatment (CER/GDP = 0.58-2.52). Conclusions Our rate of OAE failures was comparable to those of developed countries and lower than hearing loss rates noted among Nicaraguan schoolchildren, suggesting acquired or progressive etiology in the latter. Birth defects and familial hearing loss correlated with OAE failure. OAE screening of infants is feasible and cost-effective in rural Nicaragua, although highly influenced by estimated hearing loss severity in identified infants and the high travel costs incurred in a targeted screening strategy.

Non-invasive detection and monitoring of experimental hydrocephalus with distortion product otoacoustic emissions.

PubMed

Ezerarslan, Hande; Beriat, Güçlü Kaan; Nurhat, Raziye Handan; Kazancı, Burak; Çelikkan, Ferda Topal; Sabuncuoğlu, Bizden; Sabuncuoğlu, Hakan

2016-08-01

We aimed to find out the effects of short term and long term hydrocephalus and intracranial ventricular volume changes on cochlear functions by using distortion product otoacoustic emission (DPOAE) in experimental hydrocephalus rat models for the first time in literature. This study was performed with 48 healthy, adult (8 weeks old), Sprague-Dawley rats which weighed between 200 and 240g. Six groups were formed in this study: short term control, short term sham, short term hydrocephalus, long term control, long term sham and long term hydrocephalus groups. Each group contained eight rats. Short term period was 4 weeks and long term period was 8 weeks after the study started. At the end of these periods, DPOAE measurements were performed and then rats were sacrificed to determine ventricular volumes. DPOAE values at all frequencies were significantly decreased in the short term hydrocephalus group when compared to the short term control and short term sham groups. DPOAE values at all frequencies were significantly decreased in the long term hydrocephalus group when compared to the long term control and long term sham groups. Besides, long term sham group which had higher ventricular volumes than long term control group also had lower DPOAE measurements. Significant associations were present between DPOAE measurements and ventricular volumes in hydrocephalus models. The functional disturbances in cochlear functions due to hydrocephalus have been demonstrated with DPOAE measurements in this study. DPOAE measurements may be thought as an easily applicable non-invasive method in detection and follow-up of patients with hydrocephalus. Our findings should be supported with clinical studies in humans. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Automatic classification of transiently evoked otoacoustic emissions using an artificial neural network.

PubMed

Buller, G; Lutman, M E

1998-08-01

The increasing use of transiently evoked otoacoustic emissions (TEOAE) in large neonatal hearing screening programmes makes a standardized method of response classification desirable. Until now methods have been either subjective or based on arbitrary response characteristics. This study takes an expert system approach to standardize the subjective judgements of an experienced scorer. The method that is developed comprises three stages. First, it transforms TEOAEs from waveforms in the time domain into a simplified parameter set. Second, the parameter set is classified by an artificial neural network that has been taught on a large database TEOAE waveforms and corresponding expert scores. Third, additional fuzzy logic rules automatically detect probable artefacts in the waveforms and synchronized spontaneous emission components. In this way, the knowledge of the experienced scorer is encapsulated in the expert system software and thereafter can be accessed by non-experts. Teaching and evaluation of the neural network was based on TEOAEs from a database totalling 2190 neonatal hearing screening tests. The database was divided into learning and test groups with 820 and 1370 waveforms respectively. From each recorded waveform a set of 12 parameters was calculated, representing signal static and dynamic properties. The artifical network was taught with parameter sets of only the learning groups. Reproduction of the human scorer classification by the neural net in the learning group showed a sensitivity for detecting screen fails of 99.3% (299 from 301 failed results on subjective scoring) and a specificity for detecting screen passes of 81.1% (421 of 519 pass results). To quantify the post hoc performance of the net (generalization), the test group was then presented to the network input. Sensitivity was 99.4% (474 from 477) and specificity was 87.3% (780 from 893). To check the efficiency of the classification method, a second learning group was selected out of the

Theory of forward and reverse middle-ear transmission applied to otoacoustic emissions in infant and adult ears

PubMed Central

Keefe, Douglas H.; Abdala, Carolina

2008-01-01

The purpose of this study is to understand why otoacoustic emission (OAE) levels are higher in normal-hearing human infants relative to adults. In a previous study, distortion product (DP) OAE input/output (I/O) functions were shown to differ at f2=6 kHz in adults compared to infants through 6 months of age. These DPOAE I/O functions were used to noninvasively assess immaturities in forward/reverse transmission through the ear canal and middle ear [Abdala, C., and Keefe, D. H., (2006). J. Acoust Soc. Am. 120, 3832–3842]. In the present study, ear-canal reflectance and DPOAEs measured in the same ears were analyzed using a scattering-matrix model of forward and reverse transmission in the ear canal, middle ear, and cochlea. Reflectance measurements were sensitive to frequency-dependent effects of ear-canal and middle-ear transmission that differed across OAE type and subject age. Results indicated that DPOAE levels were larger in infants mainly because the reverse middle-ear transmittance level varied with ear-canal area, which differed by more than a factor of 7 between term infants and adults. The forward middle-ear transmittance level was −16 dB less in infants, so that the conductive efficiency was poorer in infants than adults. PMID:17348521

Comparing otoacoustic emissions evoked by chirp transients with constant absorbed sound power and constant incident pressure magnitude.

PubMed

Keefe, Douglas H; Feeney, M Patrick; Hunter, Lisa L; Fitzpatrick, Denis F

2017-01-01

Human ear-canal properties of transient acoustic stimuli are contrasted that utilize measured ear-canal pressures in conjunction with measured acoustic pressure reflectance and admittance. These data are referenced to the tip of a probe snugly inserted into the ear canal. Promising procedures to calibrate across frequency include stimuli with controlled levels of incident pressure magnitude, absorbed sound power, and forward pressure magnitude. An equivalent pressure at the eardrum is calculated from these measured data using a transmission-line model of ear-canal acoustics parameterized by acoustically estimated ear-canal area at the probe tip and length between the probe tip and eardrum. Chirp stimuli with constant incident pressure magnitude and constant absorbed sound power across frequency were generated to elicit transient-evoked otoacoustic emissions (TEOAEs), which were measured in normal-hearing adult ears from 0.7 to 8 kHz. TEOAE stimuli had similar peak-to-peak equivalent sound pressure levels across calibration conditions. Frequency-domain TEOAEs were compared using signal level, signal-to-noise ratio (SNR), coherence synchrony modulus (CSM), group delay, and group spread. Time-domain TEOAEs were compared using SNR, CSM, instantaneous frequency and instantaneous bandwidth. Stimuli with constant incident pressure magnitude or constant absorbed sound power across frequency produce generally similar TEOAEs up to 8 kHz.

Effects of aspirin on distortion product otoacoustic emission suppression in human adults: A comparison with neonatal data

NASA Astrophysics Data System (ADS)

Abdala, Carolina

2005-09-01

One of the distortion product otoacoustic emission (DPOAE) paradigms used to study cochlear function is DPOAE (2f1-f2) ipsilateral suppression. Newborns do not have adultlike DPOAE suppression. At 6000 Hz, infants show excessively narrow DPOAE suppression tuning and shallow growth of suppression for low-frequency suppressor tones. The source of this immaturity is not known but the outer hair cell (OHC) is one possible locus. In the present study, DPOAE suppression was measured at f2=1500 and 6000 Hz from two groups with impaired OHC function in an attempt to model the observed immaturity in neonates: adults with aspirin-induced OHC dysfunction and subjects with sensorineural hearing loss (SNHL). Their DPOAE suppression results were compared to those obtained from a group of term newborns to address whether infant DPOAE suppression resembles suppression from individuals with known OHC dysfunction. Results indicate that aspirin systematically alters DPOAE suppression in adults at f2=6000 Hz, but not 1500 Hz. However, neither aspirin-induced OHC dysfunction nor naturally occurring SNHL produces ``neonatal-like'' DPOAE suppression at either test frequency. This finding does not support the hypothesis that non-adultlike DPOAE suppression characterizing newborns can be explained by minor impairments or alterations of OHC function.

[Effect of propofol at different effect-site concentrations on approximate entropy of transient evoked otoacoustic emission signals in adults].

PubMed

Zhang, Xin-jian; Gu, Miao-ning; Xiao, Jin-fang

2009-01-01

To study the effect of propofol at different effect-site concentrations on approximate entropy (ApEn) of transient evoked otoacoustic emission (TEOAE) signals in adults and investigate the possibility of using ApEn for monitoring anesthesia depth. Fifteen ASA class I or II patients (aged 18-49 years with normal hearing) undergoing elective surgery under general anesthesia were enrolled in this study. Anesthesia was maintained with target-controlled infusion of propofol. With the effect-site concentrations of 1, 2, 3 and 4 microg/ml, TEOAE signals were monitored and recorded before and after anesthesia. ApEn of TEOAE in 4 frequency ranges (0-2, 1-3, 2.5-4.5, and 4-6 kHz) were calculated using MATLAB software. The ApEn of TEOAE in different frequency ranges showed no significant differences at the same effect-site concentration of propofol, or at different effect-site concentrations in the same frequency range (P>0.05). Anesthesia with propofol at different effect-site concentrations does not obviously affect ApEn of TEOAE signals in adults, and ApEn can not be used as the indicator for evaluating the depth of anesthesia.

Susceptibility of linear and nonlinear otoacoustic emission components to low-dose styrene exposure.

PubMed

Tognola, G; Chiaramello, E; Sisto, R; Moleti, A

2015-03-01

To investigate potential susceptibility of active cochlear mechanisms to low-level styrene exposure by comparing TEOAEs in workers and controls. Two advanced analysis techniques were applied to detect sub-clinical changes in linear and nonlinear cochlear mechanisms of OAE generation: the wavelet transform to decompose TEOAEs into time-frequency components and extract signal-to-noise ratio and latency of each component, and the bispectrum to detect and extract nonlinear TEOAE contributions as quadratic frequency couplings (QFCs). Two cohorts of workers were examined: subjects exposed exclusively to styrene (N = 9), and subjects exposed to styrene and noise (N = 6). The control group was perfectly matched by age and sex to the exposed group. Exposed subjects showed significantly lowered SNR in TEOAE components at mid-to-high frequencies (above 1.6 kHz) and a shift of QFC distribution towards lower frequencies than controls. No systematic differences were observed in latency. Low-level styrene exposure may have induced a modification of cochlear functionality as concerns linear and nonlinear OAE generation mechanisms. The lack of change in latency seems to suggest that the OAE components, where generation region and latency are tightly coupled, may not have been affected by styrene and noise exposure levels considered here.

Aftereffects of Intense Low-Frequency Sound on Spontaneous Otoacoustic Emissions: Effect of Frequency and Level.

PubMed

Jeanson, Lena; Wiegrebe, Lutz; Gürkov, Robert; Krause, Eike; Drexl, Markus

2017-02-01

The presentation of intense, low-frequency (LF) sound to the human ear can cause very slow, sinusoidal oscillations of cochlear sensitivity after LF sound offset, coined the "Bounce" phenomenon. Changes in level and frequency of spontaneous otoacoustic emissions (SOAEs) are a sensitive measure of the Bounce. Here, we investigated the effect of LF sound level and frequency on the Bounce. Specifically, the level of SOAEs was tracked for minutes before and after a 90-s LF sound exposure. Trials were carried out with several LF sound levels (93 to 108 dB SPL corresponding to 47 to 75 phons at a fixed frequency of 30 Hz) and different LF sound frequencies (30, 60, 120, 240 and 480 Hz at a fixed loudness level of 80 phons). At an LF sound frequency of 30 Hz, a minimal sound level of 102 dB SPL (64 phons) was sufficient to elicit a significant Bounce. In some subjects, however, 93 dB SPL (47 phons), the lowest level used, was sufficient to elicit the Bounce phenomenon and actual thresholds could have been even lower. Measurements with different LF sound frequencies showed a mild reduction of the Bounce phenomenon with increasing LF sound frequency. This indicates that the strength of the Bounce not only is a simple function of the spectral separation between SOAE and LF sound frequency but also depends on absolute LF sound frequency, possibly related to the magnitude of the AC component of the outer hair cell receptor potential.

The Hyperactivity of Efferent Auditory System in Patients with Schizophrenia: A Transient Evoked Otoacoustic Emissions Study

PubMed Central

Wahab, Suzaily; Abdul Rahman, Abdul Hamid; Sidek, Dinsuhaimi; Zakaria, Mohd. Normani

2016-01-01

Objective Electrophysiological studies, which are mostly focused on afferent pathway, have proven that auditory processing deficits exist in patients with schizophrenia. Nevertheless, reports on the suppressive effect of efferent auditory pathway on cochlear outer hair cells among schizophrenia patients are limited. The present, case-control, study examined the contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) in patients with schizophrenia. Methods Participants were twenty-three healthy controls and sixteen schizophrenia patients with normal hearing, middle ear and cochlear outer hair cells function. Absolute non-linear and linear TEOAEs were measured in both ears by delivering clicks stimuli at 80 dB SPL and 60 dB SPL respectively. Subsequently, contralateral suppression was determined by subtracting the absolute TEOAEs response obtained at 60 dBpe SPL during the absence and presence of contralateral white noise delivered at 65 dB HL. No attention tasks were conducted during measurements. Results We found no significant difference in absolute TEOAEs responses at 80 dB SPL, in either diagnosis or ear groups (p>0.05). However, the overall contralateral suppression was significantly larger in schizophrenia patients (p<0.05). Specifically, patients with schizophrenia demonstrated significantly increased right ear contralateral suppression compared to healthy control (p<0.05). Conclusion The present findings suggest increased inhibitory effect of efferent auditory pathway especially on the right cochlear outer hair cells. Further studies to investigate increased suppressive effects are crucial to expand the current understanding of auditory hallucination mechanisms in schizophrenia patients. PMID:26766950

The incidence of ototoxicity in child malignancy cases that received carboplatin therapy with otoacoustic emission (OAE) examination

NASA Astrophysics Data System (ADS)

Wibowo, J. K.; Zizlavsky, S.; Suwento, R.; Sjakti, H. A.; Prihartono, J.

2017-08-01

Malignancy is a significant public health problem, both globally and in Indonesia. Chemotherapy is one of the modality in malignancy cases. Carboplatin (cis-diammine-cyclobutanedi-carboxylato platinum) is a second-generation platinum compound that has often been used in the management of cases of malignancies. On the other hand, side effects of cytotoxic drugs need to be considered, especially ototoxic effects. Ototoxicity is dysfunction and damage to the structure of the inner ear that has been caused by drugs or other certain chemicals. The aim of this study is to assess ototoxic effects due to the influence of carboplatin in the cases of children with malignancy. This study uses a serial cross-sectional design to evaluate otoacoustic emission (OAE) signal-to-noise ratio (SNR) change as a result of ototoxic effects and risk factors due to the use of ototoxic carboplatin in the Division of Hematology-Oncology of the Department of Pediatrics at Cipto Mangunkusumo General Hospital in Jakarta, where two of 52 studies’ subjects experienced ototoxicity. In the group were receiving chemotherapy, two (5%) of the 40 subjects has experienced ototoxic events characterized by SNR values less than six, whereas SNR values were not less than six in the group that had not received chemotherapy. Risk factors such as gender, age, carboplatin dose, and cycles of chemotherapy did not have a statistically significant relationship to ototoxity.

Comparing otoacoustic emissions evoked by chirp transients with constant absorbed sound power and constant incident pressure magnitude

PubMed Central

Keefe, Douglas H.; Feeney, M. Patrick; Hunter, Lisa L.; Fitzpatrick, Denis F.

2017-01-01

Human ear-canal properties of transient acoustic stimuli are contrasted that utilize measured ear-canal pressures in conjunction with measured acoustic pressure reflectance and admittance. These data are referenced to the tip of a probe snugly inserted into the ear canal. Promising procedures to calibrate across frequency include stimuli with controlled levels of incident pressure magnitude, absorbed sound power, and forward pressure magnitude. An equivalent pressure at the eardrum is calculated from these measured data using a transmission-line model of ear-canal acoustics parameterized by acoustically estimated ear-canal area at the probe tip and length between the probe tip and eardrum. Chirp stimuli with constant incident pressure magnitude and constant absorbed sound power across frequency were generated to elicit transient-evoked otoacoustic emissions (TEOAEs), which were measured in normal-hearing adult ears from 0.7 to 8 kHz. TEOAE stimuli had similar peak-to-peak equivalent sound pressure levels across calibration conditions. Frequency-domain TEOAEs were compared using signal level, signal-to-noise ratio (SNR), coherence synchrony modulus (CSM), group delay, and group spread. Time-domain TEOAEs were compared using SNR, CSM, instantaneous frequency and instantaneous bandwidth. Stimuli with constant incident pressure magnitude or constant absorbed sound power across frequency produce generally similar TEOAEs up to 8 kHz. PMID:28147608

Specification of absorbed-sound power in the ear canal: Application to suppression of stimulus frequency otoacoustic emissions

PubMed Central

Keefe, Douglas H.; Schairer, Kim S.

2011-01-01

An insert ear-canal probe including sound source and microphone can deliver a calibrated sound power level to the ear. The aural power absorbed is proportional to the product of mean-squared forward pressure, ear-canal area, and absorbance, in which the sound field is represented using forward (reverse) waves traveling toward (away from) the eardrum. Forward pressure is composed of incident pressure and its multiple internal reflections between eardrum and probe. Based on a database of measurements in normal-hearing adults from 0.22 to 8 kHz, the transfer-function level of forward relative to incident pressure is boosted below 0.7 kHz and within 4 dB above. The level of forward relative to total pressure is maximal close to 4 kHz with wide variability across ears. A spectrally flat incident-pressure level across frequency produces a nearly flat absorbed power level, in contrast to 19 dB changes in pressure level. Calibrating an ear-canal sound source based on absorbed power may be useful in audiological and research applications. Specifying the tip-to-tail level difference of the suppression tuning curve of stimulus frequency otoacoustic emissions in terms of absorbed power reveals increased cochlear gain at 8 kHz relative to the level difference measured using total pressure. PMID:21361437

Neonatal hearing screening in a neonatal intensive care unit using distortion-product otoacoustic emissions.

PubMed

Chiong, Charlotte M; Llanes, Erasmo Gonzalo Dv; Tirona-Remulla, Agnes N; Calaquian, Christopher Malorre E; Reyes-Quintos, Maria-Rina T

2003-01-01

To determine pass and refer rates, and identify risk factors relating to refer responses, in neonates screened using distortion-product otoacoustic emissions (DPOAEs). A total of 435 neonates admitted to the neonatal intensive care unit (NICU) of the Philippine General Hospital between May and October 2000 were screened using DPOAEs within 48 h of admission. The male:female ratio in the sample was 1.05. In total, 56% of neonates were born preterm, the mean birthweight was 2,428.39 +/- 710.39 g and 8.9% weighed < 1,500 g. In total, 47.9% were delivered by Caesarian section and 44.9% were delivered vaginally. Almost 14% of neonates had 1-min Apgar scores of < 6, and 4% had 5-min Apgar scores of < 7. Approximately 95% of neonates had a poor perinatal history. Using pediatric aging it was noted that 46% of these neonates were born preterm. and 30.4% were small for gestational age. At least one neonatal disease was found in 42% of neonates, whilst 95.7% had to be given medication. The bilateral refer rate was 29.1%. Two-by-two analysis of risk factors for hearing loss and DPOAE measurements showed that only male sex seemed to have a significant association with a refer response. Neonates weighing < 1,500 g at birth showed a marginally significant association with a refer response (p = 0.07). All other neonates showed no crude association with DPOAE measurements. These preliminary data show that a high proportion of NICU patients may have poor outer hair cell function, and thus poor hearing. In order to develop an effective neonatal hearing screening program, further studies of prevalence and risk factors should be pursued in the same setting.

On the Relationship Between Musicianship and Contralateral Suppression of Transient-Evoked Otoacoustic Emissions.

PubMed

Stuart, Andrew; Daughtrey, Emma R

2016-04-01

The medial olivocochlear (MOC) efferent reflex that modulates outer hair cell function has been shown to be more robust in musicians versus nonmusicians as evidenced in greater contralateral suppression of transient-evoked otoacoustic emissions (TEOAEs). All previous research comparing musical ability and MOC efferent strength has defined musicianship dichotomously (i.e., high-level music students or professional classical musicians versus nonmusicians). The objective of the study was to further explore contralateral suppression of TEOAEs among adults with a full spectrum of musicianship ranging from no history of musicianship to professional musicians. Musicianship was defined by both self-report and with an objective test to quantify individual differences in perceptual music skills. A single-factor between-subjects and correlational research designs were employed. Forty-five normal-hearing young adults participated. Participants completed a questionnaire concerning their music experience and completed the Brief Profile of Music Perception Skills (PROMS) to quantify perceptual musical skills across multiple musical domains (i.e., accent, melody, tempo, and tuning). TEOAEs were evaluated with 60 dB peak equivalent sound pressure level click stimuli with and without a contralateral 65 dB sound pressure level white noise suppressor. TEOAE suppression was expressed in two ways, absolute TEOAE suppression in dB and a normalized index of TEOAE suppression (i.e., percentage of suppression). Participants who considered themselves musicians scored significantly higher on all subscales and total Brief PROMS score (p < 0.05). There was no statistically significant difference between musicians and nonmusicians in absolute TEOAE suppression or percentage of TEOAE suppression (p > 0.05). There were no statistically significant correlations or linear predictive relationships between subscale or total Brief PROMS scores with absolute and percentage of TEOAE suppression (p > 0

Comparison of distortion product otoacoustic emissions with auditory brain-stem response for clinical use in neonatal intensive care unit.

PubMed

Ochi, A; Yasuhara, A; Kobayashi, Y

1998-11-01

This study compares the clinical usefulness of distortion product otoacoustic emissions (DPOAEs) with the auditory brain-stem response (ABR) for neonates in the neonatal intensive care unit for the evaluation of hearing impairment. Both DPOAEs and ABR were performed on 36 neonates (67 ears) on the same day. We defined neonates as having normal hearing when the thresholds of wave V of ABR were < or =45 dB hearing level. (1) We could not obtain DPOAEs at f2 = 977 Hz in neonates with normal hearing because of high noise floors. DPOAE recording time was 36 min shorter than that of ABR. (2) We defined as normal DPOAEs, the number of frequencies which showed the DPgram-noise floor > or =4 dB was > or =4 at 6 f2 frequencies, from 1416 Hz to 7959 Hz. (3) Normal thresholds of ABR and normal DPOAEs showed the same percentages, i.e. 68.7%, but the percentage of different results between ABR and DPOAEs was 6.0%. Our study indicates that DPOAEs represent a simple procedure, which can be easily performed in the NICU to obtain reliable results in high-risk neonates. Results obtained by DPOAEs were comparable to those obtained by the more complex procedure of ABR.

Effects of background noise on recording of portable transient-evoked otoacoustic emission in newborn hearing screening.

PubMed

Salina, Husain; Abdullah, Asma; Mukari, Siti Zamratol Mai-sarah; Azmi, Mohd Tamil

2010-04-01

Transient-evoked otoacoustic emission (TEOAE) is a well-established screening tool for universal newborn hearing screening. The aims of this study are to measure the effects of background noise on recording of TEOAE and the duration required to complete the test at various noise levels. This study is a prospective study from June 2006 until May 2007. The study population were newborns from postnatal wards who were delivered at term pregnancy. Newborns who were more than 8-h old and passed a hearing screening testing using screening auditory brainstem response (SABRe) were further tested with TEOAE in four different test environments [isolation room in the ward during non-peak hour (E1), isolation room in the ward during peak hour (E2), maternal bedside in the ward during non-peak hour (E3) and maternal bedside in the ward during peak hour (E4)]. This study showed that test environment significantly influenced the time required to complete testing in both ears with F [534.23] = 0.945; P < 0.001 on the right ear and F [636.54] = 0.954; P < 0.001 on the left. Our study revealed that TEOAE testing was efficient in defining the presence of normal hearing in our postnatal wards at maternal bedside during non-peak hour with a specificity of 96.8%. Our study concludes that background noise levels for acceptable and accurate TEOAE recording in newborns should not exceed 65 dB A. In addition, when using TEOAE assessment in noisy environments, the time taken to obtain accurate results will greatly increase.

Objective assessment of subjective tinnitus through contralateral suppression of otoacoustic emissions by white noise; suggested cut-off points.

PubMed

Riga, M; Komis, A; Maragkoudakis, P; Korres, G; Danielides, V

2016-12-01

Normative otoacoustic emission (OAE) suppression values are currently lacking and the role of cochlear efferent innervation in tinnitus is controversial. The aim of this study was to investigate the association between tinnitus and medial olivocochlear bundle (MOCB) malfunction. Potential suppression amplitude cut-off criteria that could differentiate participants with tinnitus from those without were sought. Mean suppression amplitudes of transient evoked OAEs and distortion product OAEs by contralateral white noise (50 dBSL) were recorded. Six mean suppression amplitudes criteria were validated as possible cut-off points. The population consisted of normal hearing (n = 78) or presbycusic adults (n = 19) with tinnitus or without (n = 28 and 13, respectively) chronic tinnitus (in total, n = 138 78 females/60males, aged 49 ± 14 years). Participants with mean suppression values lower than 0.5-1 dBSPL seem to present a high probability to report tinnitus (specificity 88-97%). On the other hand, participants with mean suppression values larger than 2-2.5dBSPL seem to present a high probability of the absence of tinnitus (sensitivity 87-99%). Correlations were stronger among participants with bilateral presence or absence of tinnitus. This study seem to confirm an association between tinnitus and low suppression amplitudes (<1 dBSPL), which might evolve into an objective examination tool, supplementary to conventional audiological testing.

Optimizing Clinical Interpretation of Distortion Product Otoacoustic Emissions in Infants.

PubMed

Blankenship, Chelsea M; Hunter, Lisa L; Keefe, Douglas H; Feeney, M Patrick; Brown, David K; McCune, Annie; Fitzpatrick, Denis F; Lin, Li

2018-03-06

The purpose of this study was to analyze distortion product otoacoustic emission (DPOAE) level and signal to noise ratio in a group of infants from birth to 4 months of age to optimize prediction of hearing status. DPOAEs from infants with normal hearing (NH) and hearing loss (HL) were used to predict the presence of conductive HL (CHL), sensorineural HL (SNHL), and mixed HL (MHL). Wideband ambient absorbance was also measured and compared among the HL types. This is a prospective, longitudinal study of 279 infants with verified NH and HL, including conductive, sensorineural, and mixed types that were enrolled from a well-baby nursery and two neonatal intensive care units in Cincinnati, Ohio. At approximately 1 month of age, DPOAEs (1-8 kHz), wideband absorbance (0.25-8 kHz), and air and bone conduction diagnostic tone burst auditory brainstem response (0.5-4 kHz) thresholds were measured. Hearing status was verified at approximately 9 months of age with visual reinforcement audiometry (0.5-4 kHz). Auditory brainstem response air conduction thresholds were used to assign infants to an NH or HL group, and the efficacy of DPOAE data to classify ears as NH or HL was analyzed using receiver operating characteristic (ROC) curves. Two summary statistics of the ROC curve were calculated: the area under the ROC curve and the point of symmetry on the curve at which the sensitivity and specificity were equal. DPOAE level and signal to noise ratio cutoff values were defined at each frequency as the symmetry point on their respective ROC curve, and DPOAE results were combined across frequency in a multifrequency analysis to predict the presence of HL. Single-frequency test performance of DPOAEs was best at mid to high frequencies (3-8 kHz) with intermediate performance at 1.5 and 2 kHz and chance performance at 1 kHz. Infants with a conductive component to their HL (CHL and MHL combined) displayed significantly lower ambient absorbance values than the NH group. No differences

Sex differences in distortion product otoacoustic emissions as a function of age in CBA mice.

PubMed

Guimaraes, Patricia; Zhu, Xiaoxia; Cannon, Trinitia; Kim, SungHee; Frisina, Robert D

2004-06-01

Age-related hearing loss--presbycusis--is the number one communication problem of the aged. A major contributor to presbycusis is the progressive degeneration of cochlear outer hair cells (OHCs). Distortion product otoacoustic emissions (DPOAEs) are effective in vivo, physiological measures of hearing, assessing the health and functioning of the OHCs in mammals. We and others have previously demonstrated that DPOAE amplitudes decline with age in humans and mice. The present study's objective was to measure age-related declines in the OHCs in CBA mice (slow, progressive age-related hearing loss) by comparing DPOAEs and auditory brainstem responses (ABRs) generated from females and males. Young adult (2.1-2.9 months) and middle-aged CBA (14.0-16.4 months) mice were tested, as well as old CBAs (24.3-29.0 months). DPOAE-grams were obtained with L1 = 65 and L2 = 50 dB SPL, f1/f2 = 1.25, using eight points per octave covering a frequency range from 5.6 to 44.8 kHz (geometric mean frequency). ABRs ranged from 3 to 48 kHz. Analyses revealed that DPOAE levels decreased with age for middle-aged and old male CBAs, but for female CBAs, declines did not occur until old age - after menopause. In contrast, ABR amplitudes for female and male young adult and middle-aged CBAs were the same. Female ABR thresholds were lower than males for old CBAs. In conclusion, we discovered that pre-menopausal CBA female mice have healthier OHCs relative to middle-aged males, but much of this relative advantage is lost post-menopause. Understanding sex differences in age-related sensory disorders will be quite helpful for the goals of preventing, slowing or curing sensory problems in old age for both women and men.

Amplitude and phase of distortion product otoacoustic emissions in the guinea pig in an (f1,f2) area study

NASA Astrophysics Data System (ADS)

Schneider, Sandra; Prijs, Vera F.; Schoonhoven, Ruurd

2003-06-01

Lower sideband distortion product otoacoustic emissions (DPOAEs), measured in the ear canal upon stimulation with two continuous pure tones, are the result of interfering contributions from two different mechanisms, the nonlinear distortion component and the linear reflection component. The two contributors have been shown to have a different amplitude and, in particular, a different phase behavior as a function of the stimulus frequencies. The dominance of either component was investigated in an extensive (f1,f2) area study of DPOAE amplitude and phase in the guinea pig, which allows for both qualitative and quantitative analysis of isophase contours. Making a minimum of additional assumptions, simple relations between the direction of constant phase in the (f1,f2) plane and the group delays in f1-sweep, f2-sweep, and fixed f2/f1 paradigms can be derived, both for distortion (wave-fixed) and reflection (place-fixed) components. The experimental data indicate the presence of both components in the lower sideband DPOAEs, with the reflection component as the dominant contributor for low f2/f1 ratios and the distortion component for intermediate ratios. At high ratios the behavior cannot be explained by dominance of either component.

Audiological and electrophysiological assessment of professional pop/rock musicians.

PubMed

Samelli, Alessandra G; Matas, Carla G; Carvallo, Renata M M; Gomes, Raquel F; de Beija, Carolina S; Magliaro, Fernanda C L; Rabelo, Camila M

2012-01-01

In the present study, we evaluated peripheral and central auditory pathways in professional musicians (with and without hearing loss) compared to non-musicians. The goal was to verify if music exposure could affect auditory pathways as a whole. This is a prospective study that compared the results obtained between three groups (musicians with and without hearing loss and non-musicians). Thirty-two male individuals participated and they were assessed by: Immittance measurements, pure-tone air conduction thresholds at all frequencies from 0.25 to 20 kHz, Transient Evoked Otoacoustic Emissions, Auditory Brainstem Response (ABR), and Cognitive Potential. The musicians showed worse hearing thresholds in both conventional and high frequency audiometry when compared to the non-musicians; the mean amplitude of Transient Evoked Otoacoustic Emissions was smaller in the musicians group, but the mean latencies of Auditory Brainstem Response and Cognitive Potential were diminished in the musicians when compared to the non-musicians. Our findings suggest that the population of musicians is at risk for developing music-induced hearing loss. However, the electrophysiological evaluation showed that latency waves of ABR and P300 were diminished in musicians, which may suggest that the auditory training to which these musicians are exposed acts as a facilitator of the acoustic signal transmission to the cortex.

Distortion product otoacoustic emission (2f1-f2) amplitude growth in human adults and neonates.

PubMed

Abdala, C

2000-01-01

Distortion product otoacoustic emissions (DPOAEs) are thought to be by-products of an active amplification process in the cochlea and thus serve as a metric for evaluating the integrity of this process. Because the cochlear amplifier functions in a level-dependent fashion, DPOAEs recorded as a function of stimulus level (i.e., a DPOAE growth function) may provide important information about the range and operational characteristics of the cochlear amplifier. The DPOAE growth functions recorded in human adults and neonates may provide information about the maturation of these active cochlear processes. Two experiments were conducted. Experiment I included normal-hearing adults and term-born neonates. The 2f1-f2 DPOAE growth functions were recorded for both age groups at three f2 frequencies. Experiment II was an extension of the first experiment but added a subject group of premature neonates. The results of these studies indicate that DPOAE growth functions most often show amplitude saturation and nonmonotonic growth for all age groups. However, premature neonates show monotonic growth and the absence of amplitude saturation more often than adults. Those premature neonates who do show saturation also show an elevated threshold for amplitude saturation relative to adults. In contrast, term neonates are adultlike for most measures except that they show a larger percentage of nonsaturating growth functions than adults. These results may indicate immaturity in cochlear amplifier function prior to term birth in humans. Outer hair cell function and/or efferent regulation of outer hair cell function are hypothesized sources of this immaturity, although some contribution from the immature middle ear cannot be ruled out.

Screening for hearing loss in the elderly using distortion product otoacoustic emissions, pure tones, and a self-assessment tool.

PubMed

Jupiter, Tina

2009-12-01

To determine whether distortion product otoacoustic emissions (DPOAEs) could be used as a hearing screening tool with elderly individuals living independently, and to compare the utility of different screening protocols: (a) 3 pure-tone screening protocols consisting of 30 dB HL at 1, 2, and 3 kHz; 40 dB HL at 1, 2, and 3 kHz; or 40 dB HL at 1 and 2 kHz; (b) the Hearing Handicap Inventory for the Elderly-Screening version (HHIE-S); (c) pure tones at 40 dB HL at 1 and 2 kHz plus the HHIE-S; and (d) DPOAEs. A total of 106 elderly individuals age 65-91 years were screened using the above protocols. Pass/fail results showed that most individuals failed at 30 dB HL, followed by DPOAEs, the 40-dB HL protocols, the HHIE-S alone, and the combined pure-tone/HHIE-S protocol. All screening results were associated except the HHIE-S and 30 dB HL and the HHIE-S and DPOAEs. A McNemar analysis revealed that the differences between the correlated pass/fail results were significant except for the HHIE-S and 40 dB at 1 and 2 kHz. DPOAEs can be used to screen the elderly, with the advantage that individuals do not have to voluntarily respond to the test.

Longitudinal Development of Distortion Product Otoacoustic Emissions in Infants With Normal Hearing.

PubMed

Hunter, Lisa L; Blankenship, Chelsea M; Keefe, Douglas H; Feeney, M Patrick; Brown, David K; McCune, Annie; Fitzpatrick, Denis F; Lin, Li

2018-01-23

The purpose of this study was to describe normal characteristics of distortion product otoacoustic emission (DPOAE) signal and noise level in a group of newborns and infants with normal hearing followed longitudinally from birth to 15 months of age. This is a prospective, longitudinal study of 231 infants who passed newborn hearing screening and were verified to have normal hearing. Infants were enrolled from a well-baby nursery and two neonatal intensive care units (NICUs) in Cincinnati, OH. Normal hearing was confirmed with threshold auditory brainstem response and visual reinforcement audiometry. DPOAEs were measured in up to four study visits over the first year after birth. Stimulus frequencies f1 and f2 were used with f2/f1 = 1.22, and the DPOAE was recorded at frequency 2f1-f2. A longitudinal repeated-measure linear mixed model design was used to study changes in DPOAE level and noise level as related to age, middle ear transfer, race, and NICU history. Significant changes in the DPOAE and noise levels occurred from birth to 12 months of age. DPOAE levels were the highest at 1 month of age. The largest decrease in DPOAE level occurred between 1 and 5 months of age in the mid to high frequencies (2 to 8 kHz) with minimal changes occurring between 6, 9, and 12 months of age. The decrease in DPOAE level was significantly related to a decrease in wideband absorbance at the same f2 frequencies. DPOAE noise level increased only slightly with age over the first year with the highest noise levels in the 12-month-old age range. Minor, nonsystematic effects for NICU history, race, and gestational age at birth were found, thus these results were generalizable to commonly seen clinical populations. DPOAE levels were related to wideband middle ear absorbance changes in this large sample of infants confirmed to have normal hearing at auditory brainstem response and visual reinforcement audiometry testing. This normative database can be used to evaluate clinical results

Comparison of characteristics observed in tinnitus patients with unilateral vs bilateral symptoms, with both normal hearing threshold and distortion-product otoacoustic emissions.

PubMed

Zagólski, Olaf; Stręk, Paweł

2017-02-01

Tinnitus characteristics in normal-hearing patients differ between the groups with unilateral and bilateral complaints. The study was to determine the differences between tinnitus characteristics observed in patients with unilateral vs bilateral symptoms and normal hearing threshold, as well as normal results of distortion-product otoacoustic emissions (DPOAEs). The patients answered questions concerning tinnitus duration, laterality, character, accompanying symptoms, and circumstances of onset. The results of tympanometry, auditory brainstem responses, tinnitus likeness spectrum, minimum masking level (MML), and uncomfortable loudness level were evaluated. Records of 380 tinnitus sufferers were examined. Patients with abnormal audiograms and/or DPOAEs were excluded. The remaining 66 participants were divided into groups with unilateral and bilateral tinnitus. Unilateral tinnitus in normal-hearing patients was diagnosed twice more frequently than bilateral. Tinnitus pitch was higher in the group with bilateral tinnitus (p < .001). MML was lower in unilateral tinnitus (p < .05). Mean age of patients was higher in the unilateral tinnitus group (p < .05). Mean tinnitus duration was longer (p < .05) and hypersensitivity to sound was more frequent (p < .05) in the bilateral tinnitus group. Repeated exposure to excessive noise was the most frequent cause in the bilateral tinnitus group.

Changes in distortion product otoacoustic emission components after music exposure.

PubMed

Torre, Peter; Grace, Jennifer

2014-10-01

Young adults experience some type of recreational noise exposure on a daily basis; this includes using personal music (PM) systems with earphones. In most cases, this exposure is intermittent and the short-term effects of this exposure on the auditory system are becoming better understood. The purpose of this study was to examine the effects of one hour of music exposure using a PM system on distortion product otoacoustic emission (DPOAE) absolute levels and generator and characteristic frequency (CF) component levels. Young adults (n = 101) between 18-30 years with normal hearing participated listened to one hour of music through earphones. A second group of young adults (n = 21) served as controls and did not listen to music, but sat in the sound-treated room for one hour. Otoscopy, tympanometry, and a hearing screening (≤20 dB HL at 0.5, 1, 2, and 4 kHz) were completed in a randomly determined test ear. Preferred listening level, in dBA, was obtained and DPOAEs (2f1-f2) were measured between 1 and 6 kHz with stimulus levels fixed at L1,L2 = 55,40 dB SPL. Absolute DPOAE levels, along with generator and CF components levels were measured before and after each participant listened to one hour of music at their preferred level in a quiet setting. For data analyses, absolute DPOAE and generator and CF component levels were collapsed into 1/3rd octave bands centered around 1, 1.5, 2, 3, 4, and 6 kHz. Mean preferred listening level was 57.8 dBA, with males having a higher mean level of 61.1 dBA compared with females who had a mean level of 55.7 dBA. Females and males had negligible mean changes in absolute DPOAE levels at 1, 1.5, and 2 kHz, but males had 0.4-1 dB mean decreases after music at 3, 4, and 6 kHz compared to females, although not statistically significant. For DPOAE generator component data, females had small mean decreases for the two lower frequencies whereas males had mean decreases of 0.4-0.8 dB at 3, 4, and 6 kHz. Because of missing data, analyses of

Differences in the suppression of distortion product otoacoustic emissions by contralateral white noise between patients with acute or chronic tinnitus.

PubMed

Riga, Maria; Komis, Agis; Marangoudakis, Pavlos; Naxakis, Stefanos; Ferekidis, Eleftherios; Kandiloros, Dimitrios; Danielides, Vasilios

2017-08-01

The mechanisms underlying the shift from acute tinnitus to chronic remain obscure. An association between tinnitus and medial olivocochlear bundle (MOCB) reflex dysfunction has been hypothesised by several studies. The differences between participants with acute and chronic tinnitus have not yet been investigated. Participants were examined with distortion product otoacoustic emissions (DPOAEs) suppression elicited by contralateral white noise. They were compared in terms of frequency regions with non-recordable DPOAEs, suppression amplitudes and the presence of DPOAE enhancement. Eighteen participants with acute tinnitus, 40 age-matched adults with chronic tinnitus and 17 controls were included. All participants (aged 34.7 ± 9.6years; mean ± Standard deviation) had normal hearing. Tinnitus was bilateral in 22 participants and unilateral in 36. Ears with chronic tinnitus presented significantly lower DPOAE suppression amplitudes than ears with acute tinnitus (p < 0.0001). Both acute and chronic tinnitus ears present a high prevalence of enhancement, significantly different from controls (p < 0.0001, p = 0.0002, respectively). Non-recordable DPOAEs were significantly more frequent in the chronic than in the acute tinnitus and control groups (p < 0.0001). The differences between study groups indicate that when tinnitus becomes chronic, DPOAEs suppression presents changes that might reveal corresponding steps in tinnitus pathophysiology. Treatment implications are discussed.

Otoacoustic emissions, auditory evoked potentials and self-reported gender in people affected by disorders of sex development (DSD).

PubMed

Wisniewski, Amy B; Espinoza-Varas, Blas; Aston, Christopher E; Edmundson, Shelagh; Champlin, Craig A; Pasanen, Edward G; McFadden, Dennis

2014-08-01

Both otoacoustic emissions (OAEs) and auditory evoked potentials (AEPs) are sexually dimorphic, and both are believed to be influenced by prenatal androgen exposure. OAEs and AEPs were collected from people affected by 1 of 3 categories of disorders of sex development (DSD) - (1) women with complete androgen insensitivity syndrome (CAIS); (2) women with congenital adrenal hyperplasia (CAH); and (3) individuals with 46,XY DSD including prenatal androgen exposure who developed a male gender despite initial rearing as females (men with DSD). Gender identity (GI) and role (GR) were measured both retrospectively and at the time of study participation, using standardized questionnaires. The main objective of this study was to determine if patterns of OAEs and AEPs correlate with gender in people affected by DSD and in controls. A second objective was to assess if OAE and AEP patterns differed according to degrees of prenatal androgen exposure across groups. Control males, men with DSD, and women with CAH produced fewer spontaneous OAEs (SOAEs) - the male-typical pattern - than control females and women with CAIS. Additionally, the number of SOAEs produced correlated with gender development across all groups tested. Although some sex differences in AEPs were observed between control males and females, AEP measures did not correlate with gender development, nor did they vary according to degrees of prenatal androgen exposure, among people with DSD. Thus, OAEs, but not AEPs, may prove useful as bioassays for assessing early brain exposure to androgens and predicting gender development in people with DSD. Copyright © 2014 Elsevier Inc. All rights reserved.

Otoacoustic Emissions, Auditory Evoked Potentials and Self-Reported Gender in People Affected by Disorders of Sex Development (DSD)

PubMed Central

Wisniewski, Amy B.; Espinoza-Varas, Blas; Aston, Christopher E.; Edmundson, Shelagh; Champlin, Craig A.; Pasanen, Edward G.; McFadden, Dennis

2014-01-01

Both otoacoustic emissions (OAEs) and auditory evoked potentials (AEPs) are sexually dimorphic, and both are believed to be influenced by prenatal androgen exposure. OAEs and AEPs were collected from people affected by 1 of 3 categories of disorders of sex development (DSD) – (1) women with complete androgen insensitivity syndrome (CAIS); (2) women with congenital adrenal hyperplasia (CAH); and (3) individuals with 46, XY DSD including prenatal androgen exposure who developed a male gender despite initial rearing as females (men with DSD). Gender identity (GI) and role (GR) were measured both retrospectively and at the time of study participation, using standardized questionnaires. The main objective of this study was to determine if patterns of OAEs and AEPs correlate with gender in people affected by DSD and in controls. A second objective was to assess if OAE and AEP patterns differed according to degrees of prenatal androgen exposure across groups. Control males, men with DSD, and women with CAH produced fewer spontaneous OAEs (SOAEs) – the male-typical pattern – than control females and women with CAIS. Additionally, the number of SOAEs produced correlated with gender development across all groups tested. Although some sex differences in AEPs were observed between control males and females, AEP measures did not correlate with gender development, nor did they vary according to degrees of prenatal androgen exposure, among people with DSD. Thus, OAEs, but not AEPs, may prove useful as bioassays for assessing early brain exposure to androgens and predicting gender development in people with DSD. PMID:25038289

Distortion product otoacoustic emissions as non-invasive biomarkers and predictors of soman-induced central neurotoxicity: a preliminary study.

PubMed

Job, Agnès; Baille, Valérie; Dorandeu, Frédéric; Pouyatos, Benoît; Foquin, Annie; Delacour, Claire; Denis, Josiane; Carpentier, Pierre

2007-09-05

The organophosphorus nerve agent soman is an irreversible cholinesterase (ChE) inhibitor that can produce long-lasting seizures and brain damage in which the neurotransmitters acetylcholine and glutamate are involved. These same neurotransmitters play key-roles in the auditory function. It was then assumed that exploring the hearing function may provide markers of the central events triggered by soman intoxication. In the present study, distortion product otoacoustic emissions (DPOAEs), a non-invasive audiometric method, were used to monitor cochlear functionality in rats administered with a moderate dose of soman (45 microg/kg). DPOAEs were investigated either 4h or 24h post-challenge. In parallel, the effects of soman on whole blood and brain ChE activity and on brain histology were also studied. The first main result is that DPOAE intensities were significantly decreased 4h post-soman and returned to baseline at 24h. The amplitude changes were well related to the severity of symptoms, with the greatest change being recorded in the rats that survived long-lasting convulsions. The second main result is that baseline DPOAEs recorded 8 days before soman appear to predict the severity of symptoms produced by the intoxication. Indeed, the lowest baseline DPOAEs corresponded to the occurrence of long-lasting convulsions and brain damage and to the greatest inhibition in central ChE. These results thus suggest that DPOAEs represent a promising non-invasive tool to assess and predict the central consequences of nerve agent poisoning. Further investigations will be carried out to assess the potential applications and the limits of this non-invasive method.

Effects of reversible noise exposure on the suppression tuning of rabbit distortion-product otoacoustic emissions

NASA Astrophysics Data System (ADS)

Howard, Mackenzie A.; Stagner, Barden B.; Lonsbury-Martin, Brenda L.; Martin, Glen K.

2002-01-01

Distortion-product otoacoustic emissions (DPOAEs) at 2f1-f2 can be suppressed by the introduction of a third ``suppressor'' tone. Plotting the suppression of the DPOAE level against the changing frequency and level of the suppressor produces frequency-tuning functions referred to as suppression tuning curves (STCs). The dominant features of STCs, including their shape, are similar to the features of neural tuning curves (NTCs) recorded from single auditory nerve fibers. However, recent findings using reversible diuretics suggest that STCs do not provide the same measure of cochlear frequency selectivity as provided by NTCs. To determine if STCs are also insensitive to the adverse effects of excessive sounds, the present study exposed rabbits to a moderate-level noise that produced temporary threshold shift-like (TTS) effects on DPOAEs, and examined the influence of such exposures on STCs. DPOAEs were produced using primary tones with geometric-mean frequencies centered at 2.8 or 4 kHz, and with L1 and L2 values of 45/45, 50/35, 50/50, and 55/45 dB SPL. STCs were obtained before and during recovery for a period of approximately 2 h immediately following, and at 1, 2, 3, and 7 d post-exposure to a 2 kHz octave band noise, at levels and durations sufficient to cause significant but reversible reductions in DPOAE levels. STC data included tip center frequency, tip threshold, and Q10dB measures of tuning for suppression criteria of 3, 6, 9, and 12 dB. Recovery was variable between animals, but all rabbits recovered fully by 7 d post-exposure. STC center frequencies measured during the TTS typically tuned to a slightly higher frequency, while tip thresholds tended to decrease and Q10dB increase. Together, the results indicate that, despite similarities in the general properties of STCs and NTCs, these two types of tuning curves are affected differently following reversible cochlear insult.

Transient evoked oto-acoustic emission screening in newborns in Bogotá, Colombia: a retrospective study.

PubMed

Rojas, Jorge A; Bernal, Jaime E; García, Mary A; Zarante, Ignacio; Ramírez, Natalia; Bernal, Constanza; Gelvez, Nancy; Tamayo, Marta L

2014-10-01

The aim of this study was to investigate the characteristics and performance of transient evoked oto-acoustic emission (TEOAE) hearing screening in newborns in Colombia, and analyze all possible variables and factors affecting the results. An observational, descriptive and retrospective study with bivariate analysis was performed. The study population consisted of 56,822 newborns evaluated at the private institution, PREGEN. TEOAE testing was carried out as a pediatric hearing screening test from December 2003 to March 2012. The database from PREGEN was revised, and the protocol for evaluation included the same screening test performed twice. Demographic characteristics were recorded and the newborn's background was evaluated. Basic statistics of the qualitative and quantitative variables, and statistical analysis were obtained using the chi-square test. Of the 56,822 records examined, 0.28% were classed as abnormal, which corresponded to a prevalence of 1 in 350. In the screened newborns, 0.08% had a major abnormality or other clinical condition diagnosed, and 0.29% reported a family history of hearing loss. A prevalence of 6.7 in 10,000 was obtained for microtia, which is similar to the 6.4 in 10,000 previously reported in Colombia (database of the Latin-American Collaborative Study of Congenital Malformations - ECLAMC). Statistical analysis demonstrated an association between presenting with a major anomaly and a higher frequency of abnormal results on both TEOAE tests. Newborns in Colombia do not currently undergo screening for the early detection of hearing impairment. The results from this study suggest TEOAE screening tests, when performed twice, are able to detect hearing abnormalities in newborns. This highlights the need to improve the long-term evaluation and monitoring of patients in Colombia through diagnostic tests, and to provide tests that are both sensitive and specific. Furthermore, the use of TEOAE screening is justified by the favorable cost

Hearing and Otoacoustic Emissions Outcome of Stapedotomy: Does the Prosthesis Diameter Matter?

PubMed

Faranesh, Nabil; Magamseh, Ebrahim; Zaaroura, Suliman; Zeidan, Reem; Shupak, Avi

2017-08-01

To compare the hearing and otoacoustic emissions (OAE) outcome of stapedotomy employing 0.4 and 0.6 mm diameter prostheses. In total, 18 patients with otosclerosis participated in a prospective, double-armed, randomized cohort study. All the patients underwent small fenestra drill stapedotomy employing the Causse fluroplastic large loop piston prostheses. The patients were randomly assigned to groups of 0.4 mm (n=9) and 0.6 mm (n=9) diameter prostheses. The results of pure tone air and bone audiometries, speech audiometry, and OAE conducted 12 months post operatively were compared within and between the groups. The within-group analysis showed significant post-stapedotomy improvements in the average air conduction pure tone thresholds in both groups (52.9±9.6 vs. 25.6±5.2 dB HL; p<0.0001 and 54.6±10.4 vs. 22.2±8.2 dB HL; p<0.0001 for the 0.4 and 0.6 mm groups, respectively) and average air-bone gap (ABG; 37.1±8.5 vs. 8.1±3.9 dB HL; p<0.0001 and 38.3±7.5 vs. 9.9±4.5 dB HL; p<0.0001 in the 0.4 and 0.6 mm groups, respectively). No significant differences were found between the groups in these outcome measures, as well as in the rate of ABG closure within 10 dB HL and the word recognition scores. Favorable outcome in the post-stapedotomy bone conduction (BC) was found for the 0.6 mm prosthesis group, reflecting superior cancellation of the Carhart phenomenon for the 500-3000 Hz pure tone thresholds average (-1.7±3.7 vs. 3.9±6.2 dB HL for the 0.4 and 0.6 mm groups, respectively; p<0.04) and 1000, 2000, and 4000 Hz average (-2.6±4.33 vs. 3.9±7.8 dB HL for the 0.4 and 0.6 mm groups, respectively; p<0.05). Small signal-to-noise ratio (SNR) values of the transient-evoked OAE (TEOAE) and distortion product OAE (DPOAE) were found at baseline and follow-up evaluation with no consistent changes post stapedotomy. Similar post-stapedotomy hearing results were found for the 0.4 and 0.6 mm prostheses with small but statistically significant advantage in BC gain and the

Brainstem auditory evoked potentials in children with lead exposure.

PubMed

Alvarenga, Katia de Freitas; Morata, Thais Catalani; Lopes, Andrea Cintra; Feniman, Mariza Ribeiro; Corteletti, Lilian Cassia Bornia Jacob

2015-01-01

Earlier studies have demonstrated an auditory effect of lead exposure in children, but information on the effects of low chronic exposures needs to be further elucidated. To investigate the effect of low chronic exposures of the auditory system in children with a history of low blood lead levels, using an auditory electrophysiological test. Contemporary cross-sectional cohort. Study participants underwent tympanometry, pure tone and speech audiometry, transient evoked otoacoustic emissions, and brainstem auditory evoked potentials, with blood lead monitoring over a period of 35.5 months. The study included 130 children, with ages ranging from 18 months to 14 years, 5 months (mean age 6 years, 8 months ± 3 years, 2 months). The mean time-integrated cumulative blood lead index was 12 μg/dL (SD ± 5.7, range: 2.433). All participants had hearing thresholds equal to or below 20 dBHL and normal amplitudes of transient evoked otoacoustic emissions. No association was found between the absolute latencies of waves I, III, and V, the interpeak latencies I-III, III-V, and I-V, and the cumulative lead values. No evidence of toxic effects from chronic low lead exposures was observed on the auditory function of children living in a lead contaminated area. Copyright © 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Increased contralateral suppression of otoacoustic emissions indicates a hyperresponsive medial olivocochlear system in humans with tinnitus and hyperacusis

PubMed Central

Shera, Christopher A.; Melcher, Jennifer R.

2014-01-01

Atypical medial olivocochlear (MOC) feedback from brain stem to cochlea has been proposed to play a role in tinnitus, but even well-constructed tests of this idea have yielded inconsistent results. In the present study, it was hypothesized that low sound tolerance (mild to moderate hyperacusis), which can accompany tinnitus or occur on its own, might contribute to the inconsistency. Sound-level tolerance (SLT) was assessed in subjects (all men) with clinically normal or near-normal thresholds to form threshold-, age-, and sex-matched groups: 1) no tinnitus/high SLT, 2) no tinnitus/low SLT, 3) tinnitus/high SLT, and 4) tinnitus/low SLT. MOC function was measured from the ear canal as the change in magnitude of distortion-product otoacoustic emissions (DPOAE) elicited by broadband noise presented to the contralateral ear. The noise reduced DPOAE magnitude in all groups (“contralateral suppression”), but significantly more reduction occurred in groups with tinnitus and/or low SLT, indicating hyperresponsiveness of the MOC system compared with the group with no tinnitus/high SLT. The results suggest hyperresponsiveness of the interneurons of the MOC system residing in the cochlear nucleus and/or MOC neurons themselves. The present data, combined with previous human and animal data, indicate that neural pathways involving every major division of the cochlear nucleus manifest hyperactivity and/or hyperresponsiveness in tinnitus and/or low SLT. The overactivation may develop in each pathway separately. However, a more parsimonious hypothesis is that top-down neuromodulation is the driving force behind ubiquitous overactivation of the auditory brain stem and may correspond to attentional spotlighting on the auditory domain in tinnitus and hyperacusis. PMID:25231612

Frequency specificity and left-ear advantage of medial olivocochlear efferent modulation: a study based on stimulus frequency otoacoustic emission.

PubMed

Xing, Dongjia; Gong, Qin

2017-09-06

The medial olivocochlear (MOC) bundle is an auditory nucleus that projects efferent nerve fibers to the outer hair cells (OHCs) for synaptic innervation. The aim of the present study was to investigate the possible existence of frequency and ear specificity in MOC efferent modulation, as well as how MOC activation influences cochlear tuning. Stimulus frequency otoacoustic emissions (SFOAEs) were used to study MOC efferent modulation. Therefore, the current experiment was designed to compare the degree of SFOAE suppression in the both ears of 20 individuals at 1, 2, 4, and 8 kHz. We also compared changes in Q10 values of SFOAE suppression tuning curves at 1, 2, and 4 kHz under contralateral acoustic stimulation (CAS) and no-CAS conditions. We observed a significant reduction in SFOAE magnitude in the CAS condition compared with the no-CAS condition at 1 and 2 kHz in the left ear. A significant difference in CAS suppression was also found between the left and right ears at 1 and 2 kHz, with larger CAS suppression in the left ear. CAS further produced a statistically significant increase in the Q10 value at 1 kHz and a significant reduction in Q10 values at 2 and 4 kHz. These findings suggest a left-ear advantage in terms of CAS-induced MOC efferent SFOAE suppression, with larger MOC efferent modulation for lower frequencies, and cochlear tuning was sharpened by means of MOC activation at lower frequencies and broadened at higher frequencies.

Efficacy of Distortion Product Oto-Acoustic Emission (OAE)/Auditory Brainstem Evoked Response (ABR) Protocols in Universal Neonatal Hearing Screening and Detecting Hearing Loss in Children <2 Years of Age.

PubMed

Mishra, Girish; Sharma, Yojana; Mehta, Kanishk; Patel, Gunjan

2013-04-01

Deafness is commonest curable childhood handicap. Most remedies and programmes don't address this issue at childhood level leading to detrimental impact on development of newborns. Aims and objectives are (A) screen all newborns for deafness and detect prevalence of deafness in children less than 2 years of age. and (B) assess efficacy of multi-staged OAE/ABR protocol for hearing screening. Non-randomized, prospective study from August 2008 to August 2011. All infants underwent a series of oto-acoustic emission (OAE) and final confirmatory auditory brainstem evoked response (ABR) audiometry. Finally, out of 1,101 children, 1,069 children passed the test while 12 children had impaired hearing after final testing, confirmed by ABR. Positive predictive value of OAE after multiple test increased to 100 %. OAE-ABR test series is effective in screening neonates and multiple tests reduce economic burden. High risk screening will miss nearly 50 % deaf children, thus universal screening is indispensable in picking early deafness.

Two-tone suppression of stimulus frequency otoacoustic emissionsa)

PubMed Central

Keefe, Douglas H.; Ellison, John C.; Fitzpatrick, Denis F.; Gorga, Michael P.

2008-01-01

Stimulus frequency otoacoustic emissions (SFOAEs) measured using a suppressor tone in human ears are analogous to two-tone suppression responses measured mechanically and neurally in mammalian cochleae. SFOAE suppression was measured in 24 normal-hearing adults at octave frequencies (fp=0.5–8.0 kHz) over a 40 dB range of probe levels (Lp). Suppressor frequencies (fs) ranged from −2.0 to 0.7 octaves re: fp, and suppressor levels ranged from just detectable suppression to full suppression. The lowest suppression thresholds occurred for “best” fs slightly higher than fp. SFOAE growth of suppression (GOS) had slopes close to one at frequencies much lower than best fs, and shallow slopes near best fs, which indicated compressive growth close to 0.3 dB/dB. Suppression tuning curves constructed from GOS functions were well defined at 1, 2, and 4 kHz, but less so at 0.5 and 8.0 kHz. Tuning was sharper at lower Lp with an equivalent rectangular bandwidth similar to that reported behaviorally for simultaneous masking. The tip-to-tail difference assessed cochlear gain, increasing with decreasing Lp and increasing fp at the lowest Lp from 32 to 45 dB for fp from 1 to 4 kHz. SFOAE suppression provides a noninvasive measure of the saturating nonlinearities associated with cochlear amplification on the basilar membrane. PMID:18345837

Varicella zoster virus latency

PubMed Central

Eshleman, Emily; Shahzad, Aamir; Cohrs, Randall J

2011-01-01

Primary infection by varicella zoster virus (VZV) typically results in childhood chickenpox, at which time latency is established in the neurons of the cranial nerve, dorsal root and autonomic ganglia along the entire neuraxis. During latency, the histone-associated virus genome assumes a circular episomal configuration from which transcription is epigenetically regulated. The lack of an animal model in which VZV latency and reactivation can be studied, along with the difficulty in obtaining high-titer cell-free virus, has limited much of our understanding of VZV latency to descriptive studies of ganglia removed at autopsy and analogy to HSV-1, the prototype alphaherpesvirus. However, the lack of miRNA, detectable latency-associated transcript and T-cell surveillance during VZV latency highlight basic differences between the two neurotropic herpesviruses. This article focuses on VZV latency: establishment, maintenance and reactivation. Comparisons are made with HSV-1, with specific attention to differences that make these viruses unique human pathogens. PMID:21695042

Evaluation of the protective effect of α-lipoic acid on cisplatin ototoxicity using distortion-product otoacoustic emission measurements: an experimental animal study.

PubMed

Ozkul, Yilmaz; Songu, Murat; Basoglu, Mehmet Sinan; Ozturkcan, Sedat; Katilmis, Huseyin

2014-07-01

The aim of our study was to determine the effectiveness of intratympanic α-lipoic acid injection as an otoprotective agent against cisplatin-induced ototoxicity in guinea pigs. Twenty-four adult male albino guinea pigs with normal hearing were divided into 4 groups. The guinea pigs received intraperitoneal cisplatin in group 1, intraperitoneal cisplatin and intratympanic α-lipoic acid in group 2, intratympanic α-lipoic acid in group 3, as well as intraperitoneal cisplatin and intratympanic saline in group 4. Distortion-product otoacoustic emission measurements were obtained for both ears at the following time points: before administration (baseline recording) and on day 3 (72 h later). In group 1 (cisplatin), significant deterioration was observed at all frequencies on day 3 (P < 0.05). In group 2 (cisplatin + α-lipoic acid), deterioration was observed at all frequencies on day 3; however, this deterioration did not reach a statistical significance (P > 0.05). In group 3 (α-lipoic acid), no significant difference was observed between baseline and day 3 (P > 0.05). In group 4 (cisplatin + saline), deterioration was observed at all frequencies on day 3; however, this deterioration did not reach a statistical significance (P > 0.05). Cisplatin-induced hearing loss in the guinea pigs may be limited to some extent by the concomitant use of α-lipoic acid. Dose-dependent changes in the possible effects of α-lipoic acid need further investigation. Future morphologic studies may contribute to expose clearly the protective effect of α-lipoic acid.

Hearing impairment in children with congenital cytomegalovirus (CMV) infection based on distortion product otoacoustic emissions (DPOAE) and brain evoked response audiometry stimulus click (BERA Click) examinations

NASA Astrophysics Data System (ADS)

Airlangga, T. J.; Mangunatmadja, I.; Prihartono, J.; Zizlavsky, S.

2017-08-01

Congenital cytomegalovirus (congenital CMV) infection is a leading factor of nongenetic sensorineural hearing loss in children. Hearing loss caused by CMV infection does not have a pathognomonic configuration hence further research is needed. The development of knowledge on hearing loss caused by congenital CMV infection is progressing in many countries. Due to a lack of research in the context of Indonesia, this study assesses hearing impairment in children with congenital CMV infection in Indonesia, more specifically in the Cipto Mangunkusumo Hospital. Our objective was to profile hearing impairment in children 0-5 years of age with congenital CMV infection using Distortion Product Otoacoustic Emissions (DPOAE) and Brain Evoked Response Audiometry Stimulus Click (BERA Click) examinations. This cross-sectional study was conducted in the Cipto Mangunkusum Hospital from November, 2015 to May 2016 with 27 children 0-5 years of age with congenital CMV infection. Of individual ears studied, 58.0% exhibited sensorineural hearing loss. There was a significant relationship between developmental delay and incidence of sensorineural hearing loss. Subjects with a developmental delay were 6.57 times more likely (CI 95%; 1.88-22.87) to experience sensorineural hearing loss. Congenital CMV infection has an important role in causing sensorineural hearing loss in children.

Reduced auditory efferent activity in childhood selective mutism.

PubMed

Bar-Haim, Yair; Henkin, Yael; Ari-Even-Roth, Daphne; Tetin-Schneider, Simona; Hildesheimer, Minka; Muchnik, Chava

2004-06-01

Selective mutism is a psychiatric disorder of childhood characterized by consistent inability to speak in specific situations despite the ability to speak normally in others. The objective of this study was to test whether reduced auditory efferent activity, which may have direct bearings on speaking behavior, is compromised in selectively mute children. Participants were 16 children with selective mutism and 16 normally developing control children matched for age and gender. All children were tested for pure-tone audiometry, speech reception thresholds, speech discrimination, middle-ear acoustic reflex thresholds and decay function, transient evoked otoacoustic emission, suppression of transient evoked otoacoustic emission, and auditory brainstem response. Compared with control children, selectively mute children displayed specific deficiencies in auditory efferent activity. These aberrations in efferent activity appear along with normal pure-tone and speech audiometry and normal brainstem transmission as indicated by auditory brainstem response latencies. The diminished auditory efferent activity detected in some children with SM may result in desensitization of their auditory pathways by self-vocalization and in reduced control of masking and distortion of incoming speech sounds. These children may gradually learn to restrict vocalization to the minimal amount possible in contexts that require complex auditory processing.

Examining the role of the tectorial membrane in otoacoustic emission generation

NASA Astrophysics Data System (ADS)

Cheatham, Marry Ann; Goodyear, Richard J.; Charaziak, Karolina K.; Conklin, Tess; Zheng, Jing; Dallos, Peter; Richardson, Guy P.; Siegel, Jonathan H.

2015-12-01

A mouse lacking CEACAM16, a member of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family of proteins, shows changes in tectorial membrane (TM) structure including loss of a defined striated-sheet matrix, absence of Hensen's stripe and increased porosity. In spite of these changes, thresholds for distortion product emissions (DPOAEs) and auditory brainstem responses (ABR) are near normal for most frequencies in the mouse audiogram [11]. In contrast, stimulus frequency emissions (SFOAE) are larger in knockouts (KO) and the incidence of spontaneous emissions (SOAE) is ˜70% [5]. This latter statistic is remarkable considering that SOAEs are uncommon in normal wild-type (WT) mice. In order to understand how the TM might influence emissions, SFOAE magnitude and phase were examined and group delays computed. As in humans, an approximately one-cycle phase change is observed in association with SFOAE fine structure. In addition, CEACAM16 KO mice and their WT controls showed similar group delays/phase slopes indicating no obvious changes in the mechanisms associated with emission generation.

Telemetry System Data Latency

DTIC Science & Technology

2017-07-13

ec o n d s Data Rate TELEMETRY SYSTEM DATA LATENCY 15 of 31 Document: JT3-AFC-SRPT-17172-0005 Revision...250 So ft w ar e D ec o m L at en cy N T im es G re at er T h an D xD ec o m L at en cy Data Rate TELEMETRY SYSTEM DATA LATENCY 16 of...20.0 30.0 40.0 50.0 60.0 70.0 M ill is ec o n d s Data Rate TELEMETRY SYSTEM DATA LATENCY 17 of 31 Document:

Consistent latencies of vestibular evoked myogenic potentials.

PubMed

Wang, Shou-Jen; Yeh, Te-Huei; Chang, Chun-Hsiang; Young, Yi-Ho

2008-12-01

This study investigated the association between neck length and vestibular evoked myogenic potential (VEMP) latencies in healthy children, adolescents, and adults to elucidate when VEMP latencies reach consistent levels. Findings of VEMP tests in 14 healthy children, seven healthy adolescents, and 14 healthy adults were analyzed for correlations with neck length, which was measured as the distance of a line dropping vertically from the mastoid tip to the horizontal plane passing through the clavicle. All healthy children, adolescents, and adults exhibited present VEMP responses. Children, adolescents, and adults significantly differed in p13 latency, n23 latency, and p13-n23 interval. According to receiver operating characteristic curve analysis, the optimal cutoff values of p13 and n23 latencies between children and adults were 12.6 and 19.8 msec, respectively. Because the odds ratio of p13 latency was less than that of n23 latency, n23 latency was used to discriminate VEMP latencies between children and adults. Accordingly, a cutoff value of 15.3 cm for neck length was proposed as a criterion for predicting VEMP latency within the adult range. Consequently, a positive correlation between neck length and VEMP latency was observed when neck length was <15.3 cm, while above which level one need not account for neck length in evaluating VEMP latency. The intra-subject variability of norms can be enhanced if the normative data for VEMP characteristic parameters take structural variance into account. This study suggests that the adult range of VEMP latencies can be anticipated if neck length is >15.3 cm.

Interactions between Herpesvirus Entry Mediator (TNFRSF14) and Latency-Associated Transcript during Herpes Simplex Virus 1 Latency

PubMed Central

Allen, Sariah J.; Rhode-Kurnow, Antje; Mott, Kevin R.; Jiang, Xianzhi; Carpenter, Dale; Rodriguez-Barbosa, J. Ignacio; Jones, Clinton; Wechsler, Steven L.; Ware, Carl F.

2014-01-01

Herpesvirus entry mediator (HVEM) is one of several cell surface proteins herpes simplex virus (HSV) uses for attachment/entry. HVEM regulates cellular immune responses and can also increase cell survival. Interestingly, latency-associated transcript (LAT), the only viral gene consistently expressed during neuronal latency, enhances latency and reactivation by promoting cell survival and by helping the virus evade the host immune response. However, the mechanisms of these LAT activities are not well understood. We show here for the first time that one mechanism by which LAT enhances latency and reactivation appears to be by upregulating HVEM expression. HSV-1 latency/reactivation was significantly reduced in Hvem−/− mice, indicating that HVEM plays a significant role in HSV-1 latency/reactivation. Furthermore, LAT upregulated HVEM expression during latency in vivo and also when expressed in vitro in the absence of other viral factors. This study suggests a mechanism whereby LAT upregulates HVEM expression potentially through binding of two LAT small noncoding RNAs to the HVEM promoter and that the increased HVEM then leads to downregulation of immune responses in the latent microenvironment and increased survival of latently infected cells. Thus, one of the mechanisms by which LAT enhances latency/reactivation appears to be through increasing expression of HVEM. PMID:24307582

In vivo Knock-down of the HSV-1 Latency-Associated Transcript Reduces Reactivation from Latency.

PubMed

Watson, Zachary L; Washington, Shannan D; Phelan, Dane M; Lewin, Alfred S; Tuli, Sonal S; Schultz, Gregory S; Neumann, Donna M; Bloom, David C

2018-06-06

During Herpes Simplex Virus (HSV) latency, most viral genes are silenced with the exception of one region of the genome encoding the latency-associated transcript (LAT). This long non-coding RNA was originally described as having a role in enhancing HSV-1 reactivation. However, subsequent evidence showing that the LAT blocked apoptosis and promoted efficient establishment of latency suggested that its effects on reactivation were secondary to establishment. Here, we utilize an Adeno-associated Virus (AAV) vector to deliver a LAT-targeting hammerhead ribozyme to HSV-1-infected neurons of rabbits after the establishment of HSV-1 latency. The rabbits were then induced to reactivate latent HSV-1. Using this model, we show that decreasing LAT levels in neurons following the establishment of latency reduced the ability of the virus to reactivate. This demonstrates that the HSV-1 LAT RNA has a role in reactivation that is independent of its function in establishment of latency. In addition these results suggest the potential of AAV vectors expressing LAT-targeting ribozymes as a potential therapy for recurrent HSV disease such as herpes stromal keratitis, a leading cause of infectious blindness. Importance Herpes Simplex Virus (HSV) establishes a life long infection and remains dormant (latent) in our nerve cells. Occasionally HSV reactivates to cause disease, with HSV-1 typically causing cold sores whereas HSV-2 is the most common cause of genital herpes. The details of how HSV reactivates are largely unknown. Most of HSV's genes are silent during latency with the exception of RNAs made from the latency-associated transcript (LAT) region. While viruses that make less LAT do not reactivate efficiently, these viruses also do not establish latency as efficiently. Here we deliver a ribozyme that can degrade the LAT to the nerve cells of latently infected rabbits using a gene therapy vector. We show that this treatment blocks reactivation in the majority of the rabbits. This

Application of a zero-latency whitening filter to compact binary coalescence gravitational-wave searches

NASA Astrophysics Data System (ADS)

Tsukada, Leo; Cannon, Kipp; Hanna, Chad; Keppel, Drew; Meacher, Duncan; Messick, Cody

2018-05-01

Joint electromagnetic and gravitational-wave (GW) observation is a major goal of both the GW astronomy and electromagnetic astronomy communities for the coming decade. One way to accomplish this goal is to direct follow-up of GW candidates. Prompt electromagnetic emission may fade quickly, therefore it is desirable to have GW detection happen as quickly as possible. A leading source of latency in GW detection is the whitening of the data. We examine the performance of a zero-latency whitening filter in a detection pipeline for compact binary coalescence (CBC) GW signals. We find that the filter reproduces signal-to-noise ratio (SNR) sufficiently consistent with the results of the original high-latency and phase-preserving filter for both noise and artificial GW signals (called "injections"). Additionally, we demonstrate that these two whitening filters show excellent agreement in χ2 value, a discriminator for GW signals.

Latency in Distributed Acquisition and Rendering for Telepresence Systems.

PubMed

Ohl, Stephan; Willert, Malte; Staadt, Oliver

2015-12-01

Telepresence systems use 3D techniques to create a more natural human-centered communication over long distances. This work concentrates on the analysis of latency in telepresence systems where acquisition and rendering are distributed. Keeping latency low is important to immerse users in the virtual environment. To better understand latency problems and to identify the source of such latency, we focus on the decomposition of system latency into sub-latencies. We contribute a model of latency and show how it can be used to estimate latencies in a complex telepresence dataflow network. To compare the estimates with real latencies in our prototype, we modify two common latency measurement methods. This presented methodology enables the developer to optimize the design, find implementation issues and gain deeper knowledge about specific sources of latency.

Short-latency primate vestibuloocular responses during translation

NASA Technical Reports Server (NTRS)

Angelaki, D. E.; McHenry, M. Q.

1999-01-01

Short-lasting, transient head displacements and near target fixation were used to measure the latency and early response gain of vestibularly evoked eye movements during lateral and fore-aft translations in rhesus monkeys. The latency of the horizontal eye movements elicited during lateral motion was 11.9 +/- 5.4 ms. Viewing distance-dependent behavior was seen as early as the beginning of the response profile. For fore-aft motion, latencies were different for forward and backward displacements. Latency averaged 7.1 +/- 9.3 ms during forward motion (same for both eyes) and 12.5 +/- 6.3 ms for the adducting eye (e.g., left eye during right fixation) during backward motion. Latencies during backward motion were significantly longer for the abducting eye (18.9 +/- 9.8 ms). Initial acceleration gains of the two eyes were generally larger than unity but asymmetric. Specifically, gains were consistently larger for abducting than adducting eye movements. The large initial acceleration gains tended to compensate for the response latencies such that the early eye movement response approached, albeit consistently incompletely, that required for maintaining visual acuity during the movement. These short-latency vestibuloocular responses could complement the visually generated optic flow responses that have been shown to exhibit much longer latencies.

Advanced LIGO low-latency searches

NASA Astrophysics Data System (ADS)

Kanner, Jonah; LIGO Scientific Collaboration, Virgo Collaboration

2016-06-01

Advanced LIGO recently made the first detection of gravitational waves from merging binary black holes. The signal was first identified by a low-latency analysis, which identifies gravitational-wave transients within a few minutes of data collection. More generally, Advanced LIGO transients are sought with a suite of automated tools, which collectively identify events, evaluate statistical significance, estimate source position, and attempt to characterize source properties. This low-latency effort is enabling a broad multi-messenger approach to the science of compact object mergers and other transients. This talk will give an overview of the low-latency methodology and recent results.

Perceived ejaculatory latency and pleasure in different outlets.

PubMed

Corty, Eric W

2008-11-01

Ejaculatory latencies have been studied in coitus and with masturbation, but not with oral or manual stimulation by a partner. The present study extended research on ejaculatory latency to these outlets, and investigated the effect of perceived pleasure on self-reported ejaculatory latency. A convenience sample of male college students, not selected for sexual dysfunction, completed questionnaires assessing the outcome measures. Self-report measures of latency to ejaculation in, and perceived pleasure associated with, four different outlets (vaginal intercourse, oral intercourse, manual stimulation by a partner, and masturbation). Ejaculatory latencies in partnered activities were predictive of each other. Masturbatory latencies were predictive of coital latencies but not oral or manual stimulation latencies; all the partnered activities were predictive of each other. There was no difference in time to ejaculation among any of the partnered outlets, although ejaculation occurred more quickly with masturbation than with coitus or manual stimulation. In terms of pleasure associated with the outlets, vaginal and oral intercourse were perceived as equally pleasurable, and both were rated as more pleasurable than manual stimulation or masturbation, which did not differ from each other. These results suggest that rapidity of ejaculation is consistent across outlets for the partnered sexual activities, and that there is little unique-in terms of ejaculatory latency--about vaginal intercourse compared with oral or manual stimulation by a partner. Masturbation, however, does differ from the partnered activities. Although the average correlation, for individuals, between latency and pleasure for the different outlets is near zero, there are subgroups of men who have (i) a negative relation, (ii) a positive relation, or (iii) no relation. Results show that men, for whom greater pleasure is associated with shorter latency, are more likely to be dissatisfied with their

Evaluation of cochlear function in normal-hearing young adults exposed to MP3 player noise by analyzing transient evoked otoacoustic emissions and distortion products.

PubMed

Santaolalla Montoya, Francisco; Ibargüen, Agustín Martinez; Vences, Ana Rodriguez; del Rey, Ana Sanchez; Fernandez, Jose Maria Sanchez

2008-10-01

Exposure to recreational noise may cause injuries to the inner ear, and transient evoked (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) may identify these cochlear alterations. The goal of this study was to evaluate TEOAEs and DPOAEs as a method to diagnose early cochlear alterations in young adults exposed to MP3 player noise. We performed a prospective study of the cochlear function in normal-hearing MP3 player users by analyzing TEOAE and DPOAE incidence, amplitude, and spectral content. We gathered a sample of 40 ears from patients between 19 and 29 years old (mean age 24.09 years, SD 3.9 years). We compared the results with those of a control group of 232 ears not exposed to MP3 noise from patients aged 18 to 32 years (mean age 23.35 years, SD 2.7 years). Fifty percent of ears were from females and 50% were from males. Subjects who had used MP3 players for most years and for more hours each week exhibited a reduction in TEOAE and DPOAE incidence and amplitudes and an increase in DPOAE thresholds. TEOAEs showed a statistically significant lower incidence and amplitudes for normal-hearing subjects using MP3 players at frequencies of 2000, 3000, and 4000 Hz. DPOAE incidence was lower at 700, 1000, 1500, and 2000 Hz; the amplitudes were lower at frequencies between 1500 and 6000 Hz; and the thresholds were higher for all frequency bands, statistically significant at frequencies from 1500 to 6000 Hz, p < .05. Cochlear impairment caused by MP3 player noise exposure may be detectable by analyzing TEOAEs and DPOAEs before the impairment becomes clinically apparent.

Chirp-Evoked Otoacoustic Emissions and Middle Ear Absorbance for Monitoring Ototoxicity in Cystic Fibrosis Patients.

PubMed

Garinis, Angela C; Keefe, Douglas H; Hunter, Lisa L; Fitzpatrick, Denis F; Putterman, Daniel B; McMillan, Garnett P; Gold, Jeffrey A; Feeney, M Patrick

The goal of this study was to investigate the use of transient-evoked otoacoustic emissions (TEOAEs) and middle ear absorbance measurements to monitor auditory function in patients with cystic fibrosis (CF) receiving ototoxic medications. TEOAEs were elicited with a chirp stimulus using an extended bandwidth (0.71 to 8 kHz) to measure cochlear function at higher frequencies than traditional TEOAEs. Absorbance over a wide bandwidth (0.25 to 8 kHz) provides information on middle ear function. The combination of these time-efficient measurements has the potential to identify early signs of ototoxic hearing loss. A longitudinal study design was used to monitor the hearing of 91 patients with CF (median age = 25 years; age range = 15 to 63 years) who received known ototoxic medications (e.g., tobramycin) to prevent or treat bacterial lung infections. Results were compared to 37 normally hearing young adults (median age = 32.5 years; age range = 18 to 65 years) without a history of CF or similar treatments. Clinical testing included 226-Hz tympanometry, pure-tone air-conduction threshold testing from 0.25 to 16 kHz and bone conduction from 0.25 to 4 kHz. Experimental testing included wideband absorbance at ambient and tympanometric peak pressure and TEOAEs in three stimulus conditions: at ambient pressure and at tympanometric peak pressure using a chirp stimulus with constant incident pressure level across frequency and at ambient pressure using a chirp stimulus with constant absorbed sound power across frequency. At the initial visit, behavioral audiometric results indicated that 76 of the 157 ears (48%) from patients with CF had normal hearing, whereas 81 of these ears (52%) had sensorineural hearing loss for at least one frequency. Seven ears from four patients had a confirmed behavioral change in hearing threshold for ≥3 visits during study participation. Receiver operating characteristic curve analyses demonstrated that all three TEOAE conditions were

Handling qualities effects of display latency

NASA Technical Reports Server (NTRS)

King, David W.

1993-01-01

Display latency is the time delay between aircraft response and the corresponding response of the cockpit displays. Currently, there is no explicit specification for allowable display lags to ensure acceptable aircraft handling qualities in instrument flight conditions. This paper examines the handling qualities effects of display latency between 70 and 400 milliseconds for precision instrument flight tasks of the V-22 Tiltrotor aircraft. Display delay effects on the pilot control loop are analytically predicted through a second order pilot crossover model of the V-22 lateral axis, and handling qualities trends are evaluated through a series of fixed-base piloted simulation tests. The results show that the effects of display latency for flight path tracking tasks are driven by the stability characteristics of the attitude control loop. The data indicate that the loss of control damping due to latency can be simply predicted from knowledge of the aircraft's stability margins, control system lags, and required control bandwidths. Based on the relationship between attitude control damping and handling qualities ratings, latency design guidelines are presented. In addition, this paper presents a design philosophy, supported by simulation data, for using flight director display augmentation to suppress the effects of display latency for delays up to 300 milliseconds.

Evaluation of aural manifestations in temporo-mandibular joint dysfunction.

PubMed

Sobhy, O A; Koutb, A R; Abdel-Baki, F A; Ali, T M; El Raffa, I Z; Khater, A H

2004-08-01

Thirty patients with temporo-mandibular joint dysfunction were selected to investigate the changes in otoacoustic emissions before and after conservative treatment of their temporo-mandibular joints. Pure tone audiometry, transient-evoked otoacoustic emissions (TEOAE), distortion-product otoacoustic emissions (DPOAE) as well as a tinnitus questionnaire were administered to all patients before and after therapy. Therapy was conservative in the form of counselling, physiotherapy, anti-inflammatory agents, muscle relaxants, and occlusal splints. Results indicated insignificant changes in the TEOAEs, whereas there were significant increases in distortion product levels at most of the frequency bands. These results were paralleled to subjective improvement of tinnitus.

Signal, noise, and variation in neural and sensory-motor latency

PubMed Central

Lee, Joonyeol; Joshua, Mati; Medina, Javier F.; Lisberger, Stephen G.

2016-01-01

Analysis of the neural code for sensory-motor latency in smooth pursuit eye movements reveals general principles of neural variation and the specific origin of motor latency. The trial-by-trial variation in neural latency in MT comprises: a shared component expressed as neuron-neuron latency correlations; and an independent component that is local to each neuron. The independent component arises heavily from fluctuations in the underlying probability of spiking with an unexpectedly small contribution from the stochastic nature of spiking itself. The shared component causes the latency of single neuron responses in MT to be weakly predictive of the behavioral latency of pursuit. Neural latency deeper in the motor system is more strongly predictive of behavioral latency. A model reproduces both the variance of behavioral latency and the neuron-behavior latency correlations in MT if it includes realistic neural latency variation, neuron-neuron latency correlations in MT, and noisy gain control downstream from MT. PMID:26971946

Latency causes and reduction in optical metro networks

NASA Astrophysics Data System (ADS)

Bobrovs, Vjaceslavs; Spolitis, Sandis; Ivanovs, Girts

2013-12-01

The dramatic growth of transmitted information in fiber optical networks is leading to a concern about the network latency for high-speed reliable services like financial transactions, telemedicine, virtual and augmented reality, surveillance, and other applications. In order to ensure effective latency engineering, the delay variability needs to be accurately monitored and measured, in order to control it. This paper in brief describes causes of latency in fiber optical metro networks. Several available latency reduction techniques and solutions are also discussed, namely concerning usage of different chromatic dispersion compensation methods, low-latency amplifiers, optical fibers as well as other network elements.

[Effects of electromagnetic fields emitted by cellular phone on auditory and vestibular labyrinth].

PubMed

Sievert, U; Eggert, S; Goltz, S; Pau, H W

2007-04-01

It is the subject of this study to investigate the biological effect of the HF radiation produced by the Global System for Mobile Communications-( GSM)-mobile phone on the inner ear with its sensors of the vestibular and auditive systems. Thermographic investigations made on various model materials and on the human temporal bone should show whether mobile phone does induce any increases of temperature which would lead to a relevant stimulus for the auditive and vestibular system or not. We carried out video-nystagmographic recordings of 13 subjects, brainstem electric response audiometry of 24 ears, and recordings of distorsion products of otoacoustic emissions of 20 ears. All tests were made with and without a mobile phone in use. The data was then analyzed for variation patterns in the functional parameters of the hearing and balance system that are subject to the (non)existence of electromagnetic radiation from the mobile phone. The thermographic investigations suggest that the mobile phone does not induce any increases of temperature which would lead to a relevant stimulus for the auditive and vestibular system. Video-nystagmographic recordings under field effect do not furnish any indication of vestibular reactions generated by field effects. Compared with the recording without field, the brainstem electric response audiometry under field effect did not reveal any changes of the parameters investigated, i. e. absolute latency of the peaks I, III, V and the interpeak latency between the peaks I and V. The distorsion products of otoacoustic emissions do not indicate, comparing the three measuring situations, i. e. before field effect, pulsed field and continuous field, any possible impacts of the HF field on the spectrum or levels of emissions for none of the probands. The investigations made show that the electromagnetic fields generated in using the mobile phone do not have an effect on the inner ear and auditive system to the colliculus inferior in the

Effects of a suppressor tone on distortion product otoacoustic emissions fine structure: why a universal suppressor level is not a practical solution to obtaining single-generator DP-grams.

PubMed

Dhar, Sumitrajit; Shaffer, Lauren A

2004-12-01

The use of a suppressor tone has been proposed as the method of choice in obtaining single-generator distortion product (DP) grams, the speculation being that such DP grams will be more predictive of hearing thresholds. Current distortion product otoacoustic emissions (DPOAE) theory points to the ear canal DPOAE signal being a complex interaction between multiple components. The effectiveness of a suppressor tone is predicted to be dependent entirely on the relative levels of these components. We examine the validity of using a suppressor tone through a detailed examination of the effects of a suppressor on DPOAE fine structure in individual ears. DPOAE fine structure, recorded in 10 normal-hearing individuals with a suppressor tone at 45, 55, and 65 dB SPL, was compared with recordings without a suppressor. Behavioral hearing thresholds were also measured in the same subjects, using 2-dB steps. The effect of the suppressor tone on DPOAE fine structure varied between ears and was dependent on frequency within ears. Correlation between hearing thresholds and DPOAE level measured without a suppressor was similar to previous reports. The effects of the suppressor are explained in the theoretical framework of a model involving multiple DPOAE components. Our results suggest that a suppressor tone can have highly variable effects on fine structure across individuals or even across frequency within one ear, thereby making the use of a suppressor less viable as a clinical tool for obtaining single-generator DP grams.

Somatosensory spatial attention modulates amplitudes, latencies, and latency jitter of laser-evoked brain potentials.

PubMed

Franz, Marcel; Nickel, Moritz M; Ritter, Alexander; Miltner, Wolfgang H R; Weiss, Thomas

2015-04-01

Several studies provided evidence that the amplitudes of laser-evoked potentials (LEPs) are modulated by attention. However, previous reports were based on across-trial averaging of LEP responses at the expense of losing information about intertrial variability related to attentional modulation. The aim of this study was to investigate the effects of somatosensory spatial attention on single-trial parameters (i.e., amplitudes, latencies, and latency jitter) of LEP components (N2 and P2). Twelve subjects participated in a sustained spatial attention paradigm while noxious laser stimuli (left hand) and noxious electrical stimuli (right hand) were sequentially delivered to the dorsum of the respective hand with nonnoxious air puffs randomly interspersed within the sequence of noxious stimuli. Participants were instructed to mentally count all stimuli (i.e., noxious and nonnoxious) applied to the attended location. Laser stimuli, presented to the attended hand (ALS), elicited larger single-trial amplitudes of the N2 component compared with unattended laser stimuli (ULS). In contrast, single-trial amplitudes of the P2 component were not significantly affected by spatial attention. Single-trial latencies of the N2 and P2 were significantly smaller for ALS vs. ULS. Additionally, the across-trial latency jitter of the N2 component was reduced for ALS. Conversely, the latency jitter of the P2 component was smaller for ULS compared with ALS. With the use of single-trial analysis, the study provided new insights into brain dynamics of LEPs related to spatial attention. Our results indicate that single-trial parameters of LEP components are differentially modulated by spatial attention. Copyright © 2015 the American Physiological Society.

Proviral Latency, Persistent Human Immunodeficiency Virus Infection, and the Development of Latency Reversing Agents

PubMed Central

Archin, Nancie M.

2017-01-01

Abstract Quiescent proviral genomes that persist during human immunodeficiency virus type 1 (HIV-1) infection despite effective antiretroviral therapy (ART) can fuel rebound viremia after ART interruption and is a central obstacle to the cure of HIV infection. The induction of quiescent provirus is the goal of a new class of potential therapeutics, latency reversing agents (LRAs). The discovery, development, and testing of HIV LRAs is a key part of current efforts to develop latency reversal and viral clearance strategies to eradicate established HIV infection. The development of LRAs is burdened by many uncertainties that make drug discovery difficult. The biology of HIV latency is complex and incompletely understood. Potential targets for LRAs are host factors, and the potential toxicities of host-directed therapies in individuals that are otherwise clinically stable may be unacceptable. Assays to measure latency reversal and assess the effectiveness of potential therapeutics are complex and incompletely validated. Despite these obstacles, novel LRAs are under development and beginning to enter combination testing with viral clearance strategies. It is hoped that the steady advances in the development of LRAs now being paired with emerging immunotherapeutics to clear persistently infected cells will soon allow measurable clinical advances toward an HIV cure. PMID:28520964

Accommodation and vergence latencies in human infants

PubMed Central

Tondel, Grazyna M.; Candy, T. Rowan

2008-01-01

Purpose Achieving simultaneous single and clear visual experience during postnatal development depends on the temporal relationship between accommodation and vergence, in addition to their accuracies. This study was designed to examine one component of the dynamic relationship, the latencies of the responses. Methods Infants and adults were tested in three conditions i) Binocular viewing of a target moving in depth at 5cm/s (closed loop) ii) monocular viewing of the same target (vergence open loop) iii) binocular viewing of a low spatial frequency Difference of Gaussian target during a prism induced step change in retinal disparity (accommodation open loop). Results There was a significant correlation between accommodation and vergence latencies in binocular conditions for infants from 7 to 23 weeks of age. Some of the infants, as young as 7 or 8 weeks, generated adult-like latencies of less than 0.5 s. Latencies in the vergence open loop and accommodation open loop conditions tended to be shorter for the stimulated system than the open loop system in both cases, and all latencies were typically less than 2 seconds across the infant age range. Conclusions Many infants between 7 and 23 weeks of age were able to generate accommodation and vergence responses with latencies of less than a second in full binocular closed loop conditions. The correlation between the latencies in the two systems suggests that they are limited by related factors from the earliest ages tested. PMID:18199466

Accommodation and vergence latencies in human infants.

PubMed

Tondel, Grazyna M; Candy, T Rowan

2008-02-01

Achieving simultaneous single and clear visual experience during postnatal development depends on the temporal relationship between accommodation and vergence, in addition to their accuracies. This study was designed to examine one component of the dynamic relationship, the latencies of the responses. Infants and adults were tested in three conditions (i) binocular viewing of a target moving in depth at 5 cm/s (closed loop) (ii) monocular viewing of the same target (vergence open loop) (iii) binocular viewing of a low spatial frequency Difference of Gaussian target during a prism induced step change in retinal disparity (accommodation open loop). There was a significant correlation between accommodation and vergence latencies in binocular conditions for infants from 7 to 23 weeks of age. Some of the infants, as young as 7 or 8 weeks, generated adult-like latencies of less than 0.5 s. Latencies in the vergence open loop and accommodation open loop conditions tended to be shorter for the stimulated system than the open loop system in both cases, and all latencies were typically less than 2 s across the infant age range. Many infants between 7 and 23 weeks of age were able to generate accommodation and vergence responses with latencies of less than a second in full binocular closed loop conditions. The correlation between the latencies in the two systems suggests that they are limited by related factors from the earliest ages tested.

Effects of Bluetooth device electromagnetic field on hearing: pilot study.

PubMed

Balachandran, R; Prepageran, N; Prepagaran, N; Rahmat, O; Zulkiflee, A B; Hufaida, K S

2012-04-01

The Bluetooth wireless headset has been promoted as a 'hands-free' device with a low emission of electromagnetic radiation. To evaluate potential changes in hearing function as a consequence of using Bluetooth devices, by assessing changes in pure tone audiography and distortion production otoacoustic emissions. Prospective study. Thirty adult volunteers were exposed to a Bluetooth headset device (1) on 'standby' setting for 6 hours and (2) at full power for 10 minutes. Post-exposure hearing was evaluated using pure tone audiography and distortion production otoacoustic emission testing. There were no statistically significant changes in hearing, as measured above, following either exposure type. Exposure to the electromagnetic field emitted by a Bluetooth headset, as described above, did not decrease hearing thresholds or alter distortion product otoacoustic emissions.

Factors influencing the latency of simple reaction time

PubMed Central

Woods, David L.; Wyma, John M.; Yund, E. William; Herron, Timothy J.; Reed, Bruce

2015-01-01

Simple reaction time (SRT), the minimal time needed to respond to a stimulus, is a basic measure of processing speed. SRTs were first measured by Francis Galton in the 19th century, who reported visual SRT latencies below 190 ms in young subjects. However, recent large-scale studies have reported substantially increased SRT latencies that differ markedly in different laboratories, in part due to timing delays introduced by the computer hardware and software used for SRT measurement. We developed a calibrated and temporally precise SRT test to analyze the factors that influence SRT latencies in a paradigm where visual stimuli were presented to the left or right hemifield at varying stimulus onset asynchronies (SOAs). Experiment 1 examined a community sample of 1469 subjects ranging in age from 18 to 65. Mean SRT latencies were short (231, 213 ms when corrected for hardware delays) and increased significantly with age (0.55 ms/year), but were unaffected by sex or education. As in previous studies, SRTs were prolonged at shorter SOAs and were slightly faster for stimuli presented in the visual field contralateral to the responding hand. Stimulus detection time (SDT) was estimated by subtracting movement initiation time, measured in a speeded finger tapping test, from SRTs. SDT latencies averaged 131 ms and were unaffected by age. Experiment 2 tested 189 subjects ranging in age from 18 to 82 years in a different laboratory using a larger range of SOAs. Both SRTs and SDTs were slightly prolonged (by 7 ms). SRT latencies increased with age while SDT latencies remained stable. Precise computer-based measurements of SRT latencies show that processing speed is as fast in contemporary populations as in the Victorian era, and that age-related increases in SRT latencies are due primarily to slowed motor output. PMID:25859198

The molecular basis of herpes simplex virus latency

PubMed Central

Nicoll, Michael P; Proença, João T; Efstathiou, Stacey

2012-01-01

Herpes simplex virus type 1 is a neurotropic herpesvirus that establishes latency within sensory neurones. Following primary infection, the virus replicates productively within mucosal epithelial cells and enters sensory neurones via nerve termini. The virus is then transported to neuronal cell bodies where latency can be established. Periodically, the virus can reactivate to resume its normal lytic cycle gene expression programme and result in the generation of new virus progeny that are transported axonally back to the periphery. The ability to establish lifelong latency within the host and to periodically reactivate to facilitate dissemination is central to the survival strategy of this virus. Although incompletely understood, this review will focus on the mechanisms involved in the regulation of latency that centre on the functions of the virus-encoded latency-associated transcripts (LATs), epigenetic regulation of the latent virus genome and the molecular events that precipitate reactivation. This review considers current knowledge and hypotheses relating to the mechanisms involved in the establishment, maintenance and reactivation herpes simplex virus latency. PMID:22150699

First low-latency LIGO+Virgo search for binary inspirals and their electromagnetic counterparts

NASA Astrophysics Data System (ADS)

Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Ajith, P.; Allen, B.; Amador Ceron, E.; Amariutei, D.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Arain, M. A.; Araya, M. C.; Aston, S. M.; Astone, P.; Atkinson, D.; Aufmuth, P.; Aulbert, C.; Aylott, B. E.; Babak, S.; Baker, P.; Ballardin, G.; Ballmer, S.; Barayoga, J. C. B.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Bastarrika, M.; Basti, A.; Batch, J.; Bauchrowitz, J.; Bauer, Th. S.; Bebronne, M.; Beck, D.; Behnke, B.; Bejger, M.; Beker, M. G.; Bell, A. S.; Belletoile, A.; Belopolski, I.; Benacquista, M.; Berliner, J. M.; Bertolini, A.; Betzwieser, J.; Beveridge, N.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biswas, R.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bland, B.; Blom, M.; Bock, O.; Bodiya, T. P.; Bogan, C.; Bondarescu, R.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, S.; Bosi, L.; Bouhou, B.; Braccini, S.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Breyer, J.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burguet-Castell, J.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Calloni, E.; Camp, J. B.; Campsie, P.; Cannizzo, J.; Cannon, K.; Canuel, B.; Cao, J.; Capano, C. D.; Carbognani, F.; Carbone, L.; Caride, S.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C.; Cesarini, E.; Chaibi, O.; Chalermsongsak, T.; Charlton, P.; Chassande-Mottin, E.; Chelkowski, S.; Chen, W.; Chen, X.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Chow, J.; Christensen, N.; Chua, S. S. Y.; Chung, C. T. Y.; Chung, S.; Ciani, G.; Clara, F.; Clark, D. E.; Clark, J.; Clayton, J. H.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colacino, C. N.; Colas, J.; Colla, A.; Colombini, M.; Conte, A.; Conte, R.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M.; Coulon, J.-P.; Couvares, P.; Coward, D. M.; Cowart, M.; Coyne, D. C.; Creighton, J. D. E.; Creighton, T. D.; Cruise, A. M.; Cumming, A.; Cunningham, L.; Cuoco, E.; Cutler, R. M.; Dahl, K.; Danilishin, S. L.; Dannenberg, R.; D'Antonio, S.; Danzmann, K.; Dattilo, V.; Daudert, B.; Daveloza, H.; Davier, M.; Daw, E. J.; Day, R.; Dayanga, T.; De Rosa, R.; DeBra, D.; Debreczeni, G.; Del Pozzo, W.; del Prete, M.; Dent, T.; Dergachev, V.; DeRosa, R.; DeSalvo, R.; Dhurandhar, S.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Emilio, M. Di Paolo; Di Virgilio, A.; Díaz, M.; Dietz, A.; Donovan, F.; Dooley, K. L.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Dumas, J.-C.; Dwyer, S.; Eberle, T.; Edgar, M.; Edwards, M.; Effler, A.; Ehrens, P.; Endrőczi, G.; Engel, R.; Etzel, T.; Evans, K.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fan, Y.; Farr, B. F.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Feroz, F.; Ferrante, I.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Flanigan, M.; Foley, S.; Forsi, E.; Forte, L. A.; Fotopoulos, N.; Fournier, J.-D.; Franc, J.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Friedrich, D.; Fritschel, P.; Frolov, V. V.; Fujimoto, M.-K.; Fulda, P. J.; Fyffe, M.; Gair, J.; Galimberti, M.; Gammaitoni, L.; Garcia, J.; Garufi, F.; Gáspár, M. E.; Gemme, G.; Geng, R.; Genin, E.; Gennai, A.; Gergely, L. Á.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Giazotto, A.; Gil-Casanova, S.; Gill, C.; Gleason, J.; Goetz, E.; Goggin, L. M.; González, G.; Gorodetsky, M. L.; Goßler, S.; Gouaty, R.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Gray, N.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Greverie, C.; Grosso, R.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guido, C.; Gupta, R.; Gustafson, E. K.; Gustafson, R.; Ha, T.; Hallam, J. M.; Hammer, D.; Hammond, G.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hartman, M. T.; Haughian, K.; Hayama, K.; Hayau, J.-F.; Heefner, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hendry, M. A.; Heng, I. S.; Heptonstall, A. W.; Herrera, V.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Holtrop, M.; Hong, T.; Hooper, S.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Izumi, K.; Jacobson, M.; James, E.; Jang, Y. J.; Jaranowski, P.; Jesse, E.; Johnson, W. W.; Jones, D. I.; Jones, G.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kasturi, R.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Kelley, D.; Kells, W.; Keppel, D. G.; Keresztes, Z.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, B. K.; Kim, C.; Kim, H.; Kim, K.; Kim, N.; Kim, Y. M.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kokeyama, K.; Kondrashov, V.; Koranda, S.; Korth, W. Z.; Kowalska, I.; Kozak, D.; Kranz, O.; Kringel, V.; Krishnamurthy, S.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, R.; Kwee, P.; Lam, P. K.; Landry, M.; Lantz, B.; Lastzka, N.; Lawrie, C.; Lazzarini, A.; Leaci, P.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Leong, J. R.; Leonor, I.; Leroy, N.; Letendre, N.; Li, J.; Li, T. G. F.; Liguori, N.; Lindquist, P. E.; Liu, Y.; Liu, Z.; Lockerbie, N. A.; Lodhia, D.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J.; Luan, J.; Lubinski, M.; Lück, H.; Lundgren, A. P.; Macdonald, E.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Mageswaran, M.; Mailand, K.; Majorana, E.; Maksimovic, I.; Man, N.; Mandel, I.; Mandic, V.; Mantovani, M.; Marandi, A.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Marx, J. N.; Mason, K.; Masserot, A.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; McKechan, D. J. A.; McWilliams, S.; Meadors, G. D.; Mehmet, M.; Meier, T.; Melatos, A.; Melissinos, A. C.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Miao, H.; Michel, C.; Milano, L.; Miller, J.; Minenkov, Y.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Miyakawa, O.; Moe, B.; Mohan, M.; Mohanty, S. D.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Morgado, N.; Morgia, A.; Mori, T.; Morriss, S. R.; Mosca, S.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Müller-Ebhardt, H.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nash, T.; Naticchioni, L.; Necula, V.; Nelson, J.; Neri, I.; Newton, G.; Nguyen, T.; Nishizawa, A.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E.; Nuttall, L.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Page, A.; Pagliaroli, G.; Palladino, L.; Palomba, C.; Pan, Y.; Pankow, C.; Paoletti, F.; Papa, M. A.; Parisi, M.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patel, P.; Pedraza, M.; Peiris, P.; Pekowsky, L.; Penn, S.; Perreca, A.; Persichetti, G.; Phelps, M.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pietka, M.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Plissi, M. V.; Poggiani, R.; Pöld, J.; Postiglione, F.; Prato, M.; Predoi, V.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L. G.; Puncken, O.; Punturo, M.; Puppo, P.; Quetschke, V.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Rakhmanov, M.; Rankins, B.; Rapagnani, P.; Raymond, V.; Re, V.; Redwine, K.; Reed, C. M.; Reed, T.; Regimbau, T.; Reid, S.; Reitze, D. H.; Ricci, F.; Riesen, R.; Riles, K.; Robertson, N. A.; Robinet, F.; Robinson, C.; Robinson, E. L.; Rocchi, A.; Roddy, S.; Rodriguez, C.; Rodruck, M.; Rolland, L.; Rollins, J. G.; Romano, J. D.; Romano, R.; Romie, J. H.; Rosińska, D.; Röver, C.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sainathan, P.; Salemi, F.; Sammut, L.; Sandberg, V.; Sannibale, V.; Santamaría, L.; Santiago-Prieto, I.; Santostasi, G.; Sassolas, B.; Sathyaprakash, B. S.; Sato, S.; Saulson, P. R.; Savage, R. L.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schreiber, E.; Schulz, B.; Schutz, B. F.; Schwinberg, P.; Scott, J.; Scott, S. M.; Seifert, F.; Sellers, D.; Sentenac, D.; Sergeev, A.; Shaddock, D. A.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sibley, A.; Siemens, X.; Sigg, D.; Singer, A.; Singer, L.; Sintes, A. M.; Skelton, G. R.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M. R.; Smith, R. J. E.; Smith-Lefebvre, N. D.; Somiya, K.; Sorazu, B.; Soto, J.; Speirits, F. C.; Sperandio, L.; Stefszky, M.; Stein, A. J.; Stein, L. C.; Steinert, E.; Steinlechner, J.; Steinlechner, S.; Steplewski, S.; Stochino, A.; Stone, R.; Strain, K. A.; Strigin, S. E.; Stroeer, A. S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sung, M.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Tacca, M.; Taffarello, L.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, J. R.; Taylor, R.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Thüring, A.; Tokmakov, K. V.; Tomlinson, C.; Toncelli, A.; Tonelli, M.; Torre, O.; Torres, C.; Torrie, C. I.; Tournefier, E.; Travasso, F.; Traylor, G.; Tseng, K.; Ugolini, D.; Vahlbruch, H.; Vajente, G.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Putten, S.; van Veggel, A. A.; Vass, S.; Vasuth, M.; Vaulin, R.; Vavoulidis, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Veltkamp, C.; Verkindt, D.; Vetrano, F.; Viceré, A.; Villar, A. E.; Vinet, J.-Y.; Vitale, S.; Vocca, H.; Vorvick, C.; Vyatchanin, S. P.; Wade, A.; Wade, L.; Wade, M.; Waldman, S. J.; Wallace, L.; Wan, Y.; Wang, M.; Wang, X.; Wang, Z.; Wanner, A.; Ward, R. L.; Was, M.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D. J.; Whiting, B. F.; Wilkinson, C.; Willems, P. A.; Williams, L.; Williams, R.; Willke, B.; Winkelmann, L.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Wooley, R.; Worden, J.; Yakushin, I.; Yamamoto, H.; Yamamoto, K.; Yancey, C. C.; Yang, H.; Yeaton-Massey, D.; Yoshida, S.; Yu, P.; Yvert, M.; Zadrożny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, F.; Zhang, L.; Zhang, W.; Zhao, C.; Zotov, N.; Zucker, M. E.; Zweizig, J.

2012-05-01

Aims: The detection and measurement of gravitational-waves from coalescing neutron-star binary systems is an important science goal for ground-based gravitational-wave detectors. In addition to emitting gravitational-waves at frequencies that span the most sensitive bands of the LIGO and Virgo detectors, these sources are also amongst the most likely to produce an electromagnetic counterpart to the gravitational-wave emission. A joint detection of the gravitational-wave and electromagnetic signals would provide a powerful new probe for astronomy. Methods: During the period between September 19 and October 20, 2010, the first low-latency search for gravitational-waves from binary inspirals in LIGO and Virgo data was conducted. The resulting triggers were sent to electromagnetic observatories for followup. We describe the generation and processing of the low-latency gravitational-wave triggers. The results of the electromagnetic image analysis will be described elsewhere. Results: Over the course of the science run, three gravitational-wave triggers passed all of the low-latency selection cuts. Of these, one was followed up by several of our observational partners. Analysis of the gravitational-wave data leads to an estimated false alarm rate of once every 6.4 days, falling far short of the requirement for a detection based solely on gravitational-wave data.

Identifying Otosclerosis with Aural Acoustical Tests of Absorbance, Group Delay, Acoustic Reflex Threshold, and Otoacoustic Emissions.

PubMed

Keefe, Douglas H; Archer, Kelly L; Schmid, Kendra K; Fitzpatrick, Denis F; Feeney, M Patrick; Hunter, Lisa L

2017-10-01

Otosclerosis is a progressive middle-ear disease that affects conductive transmission through the middle ear. Ear-canal acoustic tests may be useful in the diagnosis of conductive disorders. This study addressed the degree to which results from a battery of ear-canal tests, which include wideband reflectance, acoustic stapedius muscle reflex threshold (ASRT), and transient evoked otoacoustic emissions (TEOAEs), were effective in quantifying a risk of otosclerosis and in evaluating middle-ear function in ears after surgical intervention for otosclerosis. To evaluate the ability of the test battery to classify ears as normal or otosclerotic, measure the accuracy of reflectance in classifying ears as normal or otosclerotic, and evaluate the similarity of responses in normal ears compared with ears after surgical intervention for otosclerosis. A quasi-experimental cross-sectional study incorporating case control was used. Three groups were studied: one diagnosed with otosclerosis before corrective surgery, a group that received corrective surgery for otosclerosis, and a control group. The test groups included 23 ears (13 right and 10 left) with normal hearing from 16 participants (4 male and 12 female), 12 ears (7 right and 5 left) diagnosed with otosclerosis from 9 participants (3 male and 6 female), and 13 ears (4 right and 9 left) after surgical intervention from 10 participants (2 male and 8 female). Participants received audiometric evaluations and clinical immittance testing. Experimental tests performed included ASRT tests with wideband reference signal (0.25-8 kHz), reflectance tests (0.25-8 kHz), which were parameterized by absorbance and group delay at ambient pressure and at swept tympanometric pressures, and TEOAE tests using chirp stimuli (1-8 kHz). ASRTs were measured in ipsilateral and contralateral conditions using tonal and broadband noise activators. Experimental ASRT tests were based on the difference in wideband-absorbed sound power before and after

Ego Functioning During Latency

PubMed Central

Adams, Milton S.

1979-01-01

The latency period is an extremely important transition between the preschool years and adolescence. Normal ego functioning is described, especially cognition, socialization, motor development, and defensive functions. PMID:529320

Investigation of the 2f1-f2 and 2f2-f1 distortion product otoacoustic emissions using a computational model of the gerbil ear.

PubMed

Wen, Haiqi; Bowling, Thomas; Meaud, Julien

2018-05-19

In this work, a three-dimensional computational model of the gerbil ear is used to investigate the generation of the 2f 1 -f 2 and 2f 2 -f 1 distortion product otoacoustic emissions (DPOAEs). In order to predict both the distortion and reflection sources, cochlear roughness is modeled by introducing random inhomogeneities in the outer hair cell properties. The model was used to simulate the generation of DPOAEs in response to a two-tone stimulus for various primary stimulus levels and frequency ratios. As in published experiments, the 2f 1 -f 2 DPOAEs are mostly dominated by the distortion component while the 2f 2 -f 1 DPOAEs are dominated by the reflection component; furthermore, the influence of the levels and frequency ratio of the primaries are consistent with measurements. Analysis of the intracochlear response shows that the distortion component has the highest magnitude at all longitudinal locations for the 2f 1 -f 2 distortion product (DP) while the distortion component only dominates close to the DP best place in the case of the 2f 2 -f 1 DP. Decomposition of the intracochlear DPs into forward and reverse waves demonstrates that the 2f 1 -f 2 DP generates reverse waves for both the distortion and reflection components; however, a reverse wave is only generated for the reflection component in the case of the 2f 2 -f 1 DP. As in experiments in the gerbil, the group delay of the reflection component of the DPOAE is between 1× and 2× the forward group delay, which is consistent with the propagation of DP towards the stapes as slow reverse waves. Copyright © 2018 Elsevier B.V. All rights reserved.

Short-term auditory effects of listening to an MP3 player.

PubMed

Keppler, Hannah; Dhooge, Ingeborg; Maes, Leen; D'haenens, Wendy; Bockstael, Annelies; Philips, Birgit; Swinnen, Freya; Vinck, Bart

2010-06-01

To determine the output levels of a commercially available MPEG layer-3 (MP3) player and to evaluate changes in hearing after 1 hour of listening to the MP3 player. First, A-weighted sound pressure levels (measured in decibels [dBA]) for 1 hour of pop-rock music on an MP3 player were measured on a head and torso simulator. Second, after participants listened to 1 hour of pop-rock music using an MP3 player, changes in hearing were evaluated with pure-tone audiometry, transient-evoked otoacoustic emissions, and distortion product otoacoustic emissions. Twenty-one participants were exposed to pop-rock music in 6 different sessions using 2 types of headphones at multiple preset gain settings of the MP3 player. Output levels of an MP3 player and temporary threshold and emission shifts after 1 hour of listening. The output levels at the full gain setting were 97.36 dBA and 102.56 dBA for the supra-aural headphones and stock earbuds, respectively. In the noise exposure group, significant changes in hearing thresholds and transient-evoked otoacoustic emission amplitudes were found between preexposure and postexposure measurements. However, this pattern was not seen for distortion product otoacoustic emission amplitudes. Significant differences in the incidence of significant threshold or emission shifts were observed between almost every session of the noise exposure group compared with the control group. Temporary changes in hearing sensitivity measured by audiometry and otoacoustic emissions indicate the potential harmful effects of listening to an MP3 player. Further research is needed to evaluate the long-term risk of cumulative noise exposure on the auditory system of adolescents and adults.

Methodology for Calculating Latency of GPS Probe Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhongxiang; Hamedi, Masoud; Young, Stanley

Crowdsourced GPS probe data, such as travel time on changeable-message signs and incident detection, have been gaining popularity in recent years as a source for real-time traffic information to driver operations and transportation systems management and operations. Efforts have been made to evaluate the quality of such data from different perspectives. Although such crowdsourced data are already in widespread use in many states, particularly the high traffic areas on the Eastern seaboard, concerns about latency - the time between traffic being perturbed as a result of an incident and reflection of the disturbance in the outsourced data feed - havemore » escalated in importance. Latency is critical for the accuracy of real-time operations, emergency response, and traveler information systems. This paper offers a methodology for measuring probe data latency regarding a selected reference source. Although Bluetooth reidentification data are used as the reference source, the methodology can be applied to any other ground truth data source of choice. The core of the methodology is an algorithm for maximum pattern matching that works with three fitness objectives. To test the methodology, sample field reference data were collected on multiple freeway segments for a 2-week period by using portable Bluetooth sensors as ground truth. Equivalent GPS probe data were obtained from a private vendor, and their latency was evaluated. Latency at different times of the day, impact of road segmentation scheme on latency, and sensitivity of the latency to both speed-slowdown and recovery-from-slowdown episodes are also discussed.« less

Evaluation of tinnitus patients by audiometric configuration.

PubMed

Kim, Su Il; Kim, Myung Gu; Kim, Sung Su; Byun, Jae Yong; Park, Moon Suh; Yeo, Seung Geun

2016-01-01

Although tinnitus patients have different audiometric configuration, we evaluated them using the same approach. Thus we analyzed the clinical features of patients with subjective tinnitus classified according to audiometric configuration. The study cohort consisted of 123 patients with subjective tinnitus who visited the tinnitus clinic from April 2013 to April 2014. Patients with a previous history of otologic disease or migrainous vertigo were excluded. Factors evaluated included pure tone audiometry, tinnitogram, auditory brainstem response (ABR), distortion product otoacoustic emissions (DPOAEs) and transient evoked otoacoustic emissions (TEOAEs). Tinnitus patients could be divided into three groups: Flat, high frequency gently sloping (HFGS) and high frequency steeply sloping (HFSS). HFGS showed female predominance and HFSS male predominance (p<0.05 each). THI score was higher in the HFGS than in the other groups (p<0.05). Tinnitus pitch and occupations varied, but showed specific tendencies in each group. On ABR, the HFSS group showed significant prolongation of wave I, III, and V latencies (p<0.05 each). On DPOAEs, the HFSS group showed significantly lower response rates at 3, 4, and 6 kHz (p<0.05 each). TEOAE normal rates were significantly higher in the Flat than in the HFGS and HFSS groups (p<0.05). Average pure tone thresholds were similar, but threshold values at high frequencies, ABR, DPOAEs, and TEOAEs differed among the groups. Therefore, different access to tinnitus patients could be required according to audiometric shape. Copyright © 2016 Elsevier Inc. All rights reserved.

Auditory brainstem response in neonates: influence of gender and weight/gestational age ratio

PubMed Central

Angrisani, Rosanna M. Giaffredo; Bautzer, Ana Paula D.; Matas, Carla Gentile; de Azevedo, Marisa Frasson

2013-01-01

OBJECTIVE: To investigate the influence of gender and weight/gestational age ratio on the Auditory Brainstem Response (ABR) in preterm (PT) and term (T) newborns. METHODS: 176 newborns were evaluated by ABR; 88 were preterm infants - 44 females (22 small and 22 appropriate for gestational age) and 44 males (22 small and 22 appropriate for gestational age). The preterm infants were compared to 88 term infants - 44 females (22 small and 22 appropriate for gestational age) and 44 males (22 small and 22 appropriate for gestational age). All newborns had bilateral presence of transient otoacoustic emissions and type A tympanometry. RESULTS: No interaural differences were found. ABR response did not differentiate newborns regarding weight/gestational age in males and females. Term newborn females showed statistically shorter absolute latencies (except on wave I) than males. This finding did not occur in preterm infants, who had longer latencies than term newborns, regardless of gender. CONCLUSIONS: Gender and gestational age influence term infants' ABR, with lower responses in females. The weight/gestational age ratio did not influence ABR response in either groups. PMID:24473955

Latency as a region contrast: Measuring ERP latency differences with Dynamic Time Warping.

PubMed

Zoumpoulaki, A; Alsufyani, A; Filetti, M; Brammer, M; Bowman, H

2015-12-01

Methods for measuring onset latency contrasts are evaluated against a new method utilizing the dynamic time warping (DTW) algorithm. This new method allows latency to be measured across a region instead of single point. We use computer simulations to compare the methods' power and Type I error rates under different scenarios. We perform per-participant analysis for different signal-to-noise ratios and two sizes of window (broad vs. narrow). In addition, the methods are tested in combination with single-participant and jackknife average waveforms for different effect sizes, at the group level. DTW performs better than the other methods, being less sensitive to noise as well as to placement and width of the window selected. © 2015 Society for Psychophysiological Research.

Click- and chirp-evoked human compound action potentials

PubMed Central

Chertoff, Mark; Lichtenhan, Jeffery; Willis, Marie

2010-01-01

In the experiments reported here, the amplitude and the latency of human compound action potentials (CAPs) evoked from a chirp stimulus are compared to those evoked from a traditional click stimulus. The chirp stimulus was created with a frequency sweep to compensate for basilar membrane traveling wave delay using the O-Chirp equations from Fobel and Dau [(2004). J. Acoust. Soc. Am. 116, 2213–2222] derived from otoacoustic emission data. Human cochlear traveling wave delay estimates were obtained from derived compound band action potentials provided by Eggermont [(1979). J. Acoust. Soc. Am. 65, 463–470]. CAPs were recorded from an electrode placed on the tympanic membrane (TM), and the acoustic signals were monitored with a probe tube microphone attached to the TM electrode. Results showed that the amplitude and latency of chirp-evoked N1 of the CAP differed from click-evoked CAPs in several regards. For the chirp-evoked CAP, the N1 amplitude was significantly larger than the click-evoked N1s. The latency-intensity function was significantly shallower for chirp-evoked CAPs as compared to click-evoked CAPs. This suggests that auditory nerve fibers respond with more unison to a chirp stimulus than to a click stimulus. PMID:21117748

Predictive Displays for High Latency Teleoperation

DTIC Science & Technology

2016-08-04

PREDICTIVE DISPLAYS FOR HIGH LATENCY TELEOPERATION” Analysis of existing approach 3 C om m s. C hannel Vehicle OCU D Throttle, Steer, Brake D Video ...presents opportunity mitigate outgoing latency. • Video is not governed by physics, however, video is dependent on the state of the vehicle, which...Commands, estimates UDP: H.264 Video UDP: Vehicle state • C++ implementation • 2 threads • OpenCV for image manipulation • FFMPEG for video decoding

Low Latency Messages on Distributed Memory Multiprocessors

DOE PAGES

Rosing, Matt; Saltz, Joel

1995-01-01

This article describes many of the issues in developing an efficient interface for communication on distributed memory machines. Although the hardware component of message latency is less than 1 ws on many distributed memory machines, the software latency associated with sending and receiving typed messages is on the order of 50 μs. The reason for this imbalance is that the software interface does not match the hardware. By changing the interface to match the hardware more closely, applications with fine grained communication can be put on these machines. This article describes several tests performed and many of the issues involvedmore » in supporting low latency messages on distributed memory machines.« less

Monitoring data transfer latency in CMS computing operations

DOE PAGES

Bonacorsi, Daniele; Diotalevi, Tommaso; Magini, Nicolo; ...

2015-12-23

During the first LHC run, the CMS experiment collected tens of Petabytes of collision and simulated data, which need to be distributed among dozens of computing centres with low latency in order to make efficient use of the resources. While the desired level of throughput has been successfully achieved, it is still common to observe transfer workflows that cannot reach full completion in a timely manner due to a small fraction of stuck files which require operator intervention.For this reason, in 2012 the CMS transfer management system, PhEDEx, was instrumented with a monitoring system to measure file transfer latencies, andmore » to predict the completion time for the transfer of a data set. The operators can detect abnormal patterns in transfer latencies while the transfer is still in progress, and monitor the long-term performance of the transfer infrastructure to plan the data placement strategy.Based on the data collected for one year with the latency monitoring system, we present a study on the different factors that contribute to transfer completion time. As case studies, we analyze several typical CMS transfer workflows, such as distribution of collision event data from CERN or upload of simulated event data from the Tier-2 centres to the archival Tier-1 centres. For each workflow, we present the typical patterns of transfer latencies that have been identified with the latency monitor.We identify the areas in PhEDEx where a development effort can reduce the latency, and we show how we are able to detect stuck transfers which need operator intervention. Lastly, we propose a set of metrics to alert about stuck subscriptions and prompt for manual intervention, with the aim of improving transfer completion times.« less

Monitoring data transfer latency in CMS computing operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonacorsi, Daniele; Diotalevi, Tommaso; Magini, Nicolo

During the first LHC run, the CMS experiment collected tens of Petabytes of collision and simulated data, which need to be distributed among dozens of computing centres with low latency in order to make efficient use of the resources. While the desired level of throughput has been successfully achieved, it is still common to observe transfer workflows that cannot reach full completion in a timely manner due to a small fraction of stuck files which require operator intervention.For this reason, in 2012 the CMS transfer management system, PhEDEx, was instrumented with a monitoring system to measure file transfer latencies, andmore » to predict the completion time for the transfer of a data set. The operators can detect abnormal patterns in transfer latencies while the transfer is still in progress, and monitor the long-term performance of the transfer infrastructure to plan the data placement strategy.Based on the data collected for one year with the latency monitoring system, we present a study on the different factors that contribute to transfer completion time. As case studies, we analyze several typical CMS transfer workflows, such as distribution of collision event data from CERN or upload of simulated event data from the Tier-2 centres to the archival Tier-1 centres. For each workflow, we present the typical patterns of transfer latencies that have been identified with the latency monitor.We identify the areas in PhEDEx where a development effort can reduce the latency, and we show how we are able to detect stuck transfers which need operator intervention. Lastly, we propose a set of metrics to alert about stuck subscriptions and prompt for manual intervention, with the aim of improving transfer completion times.« less

Latency and User Performance in Virtual Environments and Augmented Reality

NASA Technical Reports Server (NTRS)

Ellis, Stephen R.

2009-01-01

System rendering latency has been recognized by senior researchers, such as Professor Fredrick Brooks of UNC (Turing Award 1999), as a major factor limiting the realism and utility of head-referenced displays systems. Latency has been shown to reduce the user's sense of immersion within a virtual environment, disturb user interaction with virtual objects, and to contribute to motion sickness during some simulation tasks. Latency, however, is not just an issue for external display systems since finite nerve conduction rates and variation in transduction times in the human body's sensors also pose problems for latency management within the nervous system. Some of the phenomena arising from the brain's handling of sensory asynchrony due to latency will be discussed as a prelude to consideration of the effects of latency in interactive displays. The causes and consequences of the erroneous movement that appears in displays due to latency will be illustrated with examples of the user performance impact provided by several experiments. These experiments will review the generality of user sensitivity to latency when users judge either object or environment stability. Hardware and signal processing countermeasures will also be discussed. In particular the tuning of a simple extrapolative predictive filter not using a dynamic movement model will be presented. Results show that it is possible to adjust this filter so that the appearance of some latencies may be hidden without the introduction of perceptual artifacts such as overshoot. Several examples of the effects of user performance will be illustrated by three-dimensional tracking and tracing tasks executed in virtual environments. These experiments demonstrate classic phenomena known from work on manual control and show the need for very responsive systems if they are indented to support precise manipulation. The practical benefits of removing interfering latencies from interactive systems will be emphasized with some

Cochlear Microphonic and Summating Potential Responses from Click-Evoked Auditory Brain Stem Responses in High-Risk and Normal Infants.

PubMed

Hunter, Lisa L; Blankenship, Chelsea M; Gunter, Rebekah G; Keefe, Douglas H; Feeney, M Patrick; Brown, David K; Baroch, Kelly

2018-05-01

effects in their ECochG or ABR responses when tested at about one-month corrected age. These data may serve as a normative sample for NICU and well infant ECochG and ABR latencies at one-month corrected age. Two infant case studies, one diagnosed with AN and another with SNHL demonstrated the complexity of using ECochG and otoacoustic emissions to assess the risk of AN in individual cases. CM and SPs can be readily measured using standard click stimuli in both well and NICU infants. Normative ranges for latency and amplitude are useful for interpreting ECochG and ABR components. Inclusion of ECochG and ABR tests in a test battery that also includes otoacoustic emission and acoustic reflex tests may provide a more refined assessment of the risks of AN and SNHL in infants. American Academy of Audiology.

The relationship between distortion product otoacoustic emissions and extended high-frequency audiometry in tinnitus patients. Part 1: normally hearing patients with unilateral tinnitus.

PubMed

Fabijańska, Anna; Smurzyński, Jacek; Hatzopoulos, Stavros; Kochanek, Krzysztof; Bartnik, Grażyna; Raj-Koziak, Danuta; Mazzoli, Manuela; Skarżyński, Piotr H; Jędrzejczak, Wieslaw W; Szkiełkowska, Agata; Skarżyński, Henryk

2012-12-01

The aim of this study was to evaluate distortion product otoacoustic emissions (DPOAEs) and extended high-frequency (EHF) thresholds in a control group and in patients with normal hearing sensitivity in the conventional frequency range and reporting unilateral tinnitus. Seventy patients were enrolled in the study: 47 patients with tinnitus in the left ear (Group 1) and 23 patients with tinnitus in the right ear (Group 2). The control group included 60 otologically normal subjects with no history of pathological tinnitus. Pure-tone thresholds were measured at all standard frequencies from 0.25 to 8 kHz, and at 10, 12.5, 14, and 16 kHz. The DPOAEs were measured in the frequency range from approximately 0.5 to 9 kHz using the primary tones presented at 65/55 dB SPL. The left ears of patients in Group 1 had higher median hearing thresholds than those in the control subjects at all 4 EHFs, and lower mean DPOAE levels than those in the controls for almost all primary frequencies, but significantly lower only in the 2-kHz region. Median hearing thresholds in the right ears of patients in Group 2 were higher than those in the right ears of the control subjects in the EHF range at 12.5, 14, and 16 kHz. The mean DPOAE levels in the right ears were lower in patients from Group 2 than those in the controls for the majority of primary frequencies, but only reached statistical significance in the 8-kHz region. Hearing thresholds in tinnitus ears with normal hearing sensitivity in the conventional range were higher in the EHF region than those in non-tinnitus control subjects, implying that cochlear damage in the basal region may result in the perception of tinnitus. In general, DPOAE levels in tinnitus ears were lower than those in ears of non-tinnitus subjects, suggesting that subclinical cochlear impairment in limited areas, which can be revealed by DPOAEs but not by conventional audiometry, may exist in tinnitus ears. For patients with tinnitus, DPOAE measures combined with

MicroRNA-155 Reinforces HIV Latency*

PubMed Central

Ruelas, Debbie S.; Chan, Jonathan K.; Oh, Eugene; Heidersbach, Amy J.; Hebbeler, Andrew M.; Chavez, Leonard; Verdin, Eric; Rape, Michael; Greene, Warner C.

2015-01-01

The presence of a small number of infected but transcriptionally dormant cells currently thwarts a cure for the more than 35 million individuals infected with HIV. Reactivation of these latently infected cells may result in three fates: 1) cell death due to a viral cytopathic effect, 2) cell death due to immune clearance, or 3) a retreat into latency. Uncovering the dynamics of HIV gene expression and silencing in the latent reservoir will be crucial for developing an HIV-1 cure. Here we identify and characterize an intracellular circuit involving TRIM32, an HIV activator, and miR-155, a microRNA that may promote a return to latency in these transiently activated reservoir cells. Notably, we demonstrate that TRIM32, an E3 ubiquitin ligase, promotes reactivation from latency by directly modifying IκBα, leading to a novel mechanism of NF-κB induction not involving IκB kinase activation. PMID:25873391

Pursuit Latency for Chromatic Targets

NASA Technical Reports Server (NTRS)

Mulligan, Jeffrey B.; Ellis, Stephen R. (Technical Monitor)

1998-01-01

The temporal dynamics of eye movement response to a change in direction of stimulus motion has been used to compare the processing speeds of different types of stimuli (Mulligan, ARVO '97). In this study, the pursuit response to colored targets was measured to test the hypothesis that the slow response of the chromatic system (as measured using traditional temporal sensitivity measures such as contrast sensitivity) results in increased eye movement latencies. Subjects viewed a small (0.4 deg) Gaussian spot which moved downward at a speed of 6.6 deg/sec. At a variable time during the trajectory, the dot's direction of motion changed by 30 degrees, either to the right or left. Subjects were instructed to pursue the spot. Eye movements were measured using a video ophthalmoscope with an angular resolution of approximately 1 arc min and a temporal sampling rate of 60 Hz. Stimuli were modulated in chrominance for a variety of hue directions, combined with a range of small luminance increments and decrements, to insure that some of the stimuli fell in the subjects' equiluminance planes. The smooth portions of the resulting eye movement traces were fit by convolving the stimulus velocity with an exponential having variable onset latency, time constant and amplitude. Smooth eye movements with few saccades were observed for all stimuli. Pursuit responses to stimuli having a significant luminance component are well-fit by exponentials having latencies and time constants on the order of 100 msec. Increases in pursuit response latency on the order of 100-200 msec are observed in response to certain stimuli, which occur in pairs of complementary hues, corresponding to the intersection of the stimulus section with the subjects' equiluminant plane. Smooth eye movements can be made in response to purely chromatic stimuli, but are slower than responses to stimuli with a luminance component.

Evaluation of Jet Fuel and Noise-Induced Hearing Loss in Rats (Rattus norvegicus)

DTIC Science & Technology

2014-05-13

product otoacoustic emissions (DPOAE) and compound action potential (CAP) testing of the cochlear nerve. Inner ear hair cell loss was also not affected...conclusion by revealing that exposure to JP-8 combined with noise may result in the loss of pre-neural cochlear sensitivity as shown by suppression of...distortion product otoacoustic emissions (DPOAE) and depletion of cochlear sensory cells as evidenced by cytocochleograms that plot the percentage of

Avoiding and tolerating latency in large-scale next-generation shared-memory multiprocessors

NASA Technical Reports Server (NTRS)

Probst, David K.

1993-01-01

A scalable solution to the memory-latency problem is necessary to prevent the large latencies of synchronization and memory operations inherent in large-scale shared-memory multiprocessors from reducing high performance. We distinguish latency avoidance and latency tolerance. Latency is avoided when data is brought to nearby locales for future reference. Latency is tolerated when references are overlapped with other computation. Latency-avoiding locales include: processor registers, data caches used temporally, and nearby memory modules. Tolerating communication latency requires parallelism, allowing the overlap of communication and computation. Latency-tolerating techniques include: vector pipelining, data caches used spatially, prefetching in various forms, and multithreading in various forms. Relaxing the consistency model permits increased use of avoidance and tolerance techniques. Each model is a mapping from the program text to sets of partial orders on program operations; it is a convention about which temporal precedences among program operations are necessary. Information about temporal locality and parallelism constrains the use of avoidance and tolerance techniques. Suitable architectural primitives and compiler technology are required to exploit the increased freedom to reorder and overlap operations in relaxed models.

Temporal processing and long-latency auditory evoked potential in stutterers.

PubMed

Prestes, Raquel; de Andrade, Adriana Neves; Santos, Renata Beatriz Fernandes; Marangoni, Andrea Tortosa; Schiefer, Ana Maria; Gil, Daniela

Stuttering is a speech fluency disorder, and may be associated with neuroaudiological factors linked to central auditory processing, including changes in auditory processing skills and temporal resolution. To characterize the temporal processing and long-latency auditory evoked potential in stutterers and to compare them with non-stutterers. The study included 41 right-handed subjects, aged 18-46 years, divided into two groups: stutterers (n=20) and non-stutters (n=21), compared according to age, education, and sex. All subjects were submitted to the duration pattern tests, random gap detection test, and long-latency auditory evoked potential. Individuals who stutter showed poorer performance on Duration Pattern and Random Gap Detection tests when compared with fluent individuals. In the long-latency auditory evoked potential, there was a difference in the latency of N2 and P3 components; stutterers had higher latency values. Stutterers have poor performance in temporal processing and higher latency values for N2 and P3 components. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Comparison of Sleep Latency and Number of SOREMPs in the Home and Hospital With a Modified Multiple Sleep Latency Test: A Randomized Crossover Study.

PubMed

Beiske, Kornelia K; Sand, Trond; Rugland, Eyvind; Stavem, Knut

2017-05-01

Comparison of mean sleep latencies and number of sleep-onset rapid eye movement periods (SOREMPs) between modified multiple sleep latency test (MSLT) performed in the unattended home and in-hospital laboratory setting. A randomized crossover single-blinded design. Thirty-four subjects referred to MSLT for suspected hypersomnia or narcolepsy were included. Participants were randomized to perform modified MSLT in the unattended home or in the hospital first. Scores in the two settings were compared using Wilcoxon signed-rank test or exact McNemar test. Agreement between home and hospital categorized mean sleep latency and number of SOREMPs was assessed using simple kappa (κ) and proportion agreement. Agreement between home and hospital mean sleep latency was assessed using a Bland-Altman plot and an intraclass correlation coefficient. There was no difference between home and hospital assessment of mean sleep latency (P = 0.86). Two or more SOREMPs were found more frequently on modified MSLTs performed at home compared with those at the hospital (7 and 2, respectively; P = 0.025). Agreement was moderate for categorized sleep latency (κ = 0.53) and fair for categorized SOREMPs (κ = 0.39) in the 2 settings. Analysis of mean sleep latency using intraclass correlation coefficient showed a very good agreement between the two settings. Group mean sleep latency for home modified MSLTs seems to be reliable compared with that for the attended sleep-laboratory setting. Higher rate of SOREMP in the unattended home suggests that napping in a familiar environment facilitates the transition into REM sleep. Further studies are needed to assess the normal limit, sensitivity, and specificity for SOREMP at home before the clinical utility of home-based napping can be determined.

Long-latency auditory evoked potentials with verbal and nonverbal stimuli.

PubMed

Oppitz, Sheila Jacques; Didoné, Dayane Domeneghini; Silva, Débora Durigon da; Gois, Marjana; Folgearini, Jordana; Ferreira, Geise Corrêa; Garcia, Michele Vargas

2015-01-01

Long-latency auditory evoked potentials represent the cortical activity related to attention, memory, and auditory discrimination skills. Acoustic signal processing occurs differently between verbal and nonverbal stimuli, influencing the latency and amplitude patterns. To describe the latencies of the cortical potentials P1, N1, P2, N2, and P3, as well as P3 amplitude, with different speech stimuli and tone bursts, and to classify them in the presence and absence of these data. A total of 30 subjects with normal hearing were assessed, aged 18-32 years old, matched by gender. Nonverbal stimuli were used (tone burst; 1000Hz - frequent and 4000Hz - rare); and verbal (/ba/ - frequent; /ga/, /da/, and /di/ - rare). Considering the component N2 for tone burst, the lowest latency found was 217.45ms for the BA/DI stimulus; the highest latency found was 256.5ms. For the P3 component, the shortest latency with tone burst stimuli was 298.7 with BA/GA stimuli, the highest, was 340ms. For the P3 amplitude, there was no statistically significant difference among the different stimuli. For latencies of components P1, N1, P2, N2, P3, there were no statistical differences among them, regardless of the stimuli used. There was a difference in the latency of potentials N2 and P3 among the stimuli employed but no difference was observed for the P3 amplitude. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

In vivo expression of human cytomegalovirus (HCMV) microRNAs during latency.

PubMed

Meshesha, Mesfin K; Bentwich, Zvi; Solomon, Semaria A; Avni, Yonat Shemer

2016-01-01

Viral encoded microRNAs play key roles in regulating gene expression and the life cycle of human herpes viruses. Latency is one of the hallmarks of the human cytomegalovirus (HCMV or HHV5) life cycle, and its control may have immense practical applications. The present study aims to identify HCMV encoded microRNAs during the latency phase of the virus. We used a highly sensitive real time PCR (RTPCR) assay that involves a pre-amplification step before RTPCR. It can detect HCMV encoded microRNAs (miRNAs) during latency in purified monocytes and PBMCs from HCMV IgG positive donors and in latently infected monocytic THP-1 cell lines. During the latency phase, only eight HCMV encoded microRNAs were detected in PBMCs, monocytes and in the THP-1 cells. Five originated from the UL region of the virus genome and three from the US region. Reactivation of the virus from latency, in monocytes obtained from the same donor, using dexamethasone restored the expression of all known HCMV encoded miRNAs including those that were absent during latency. We observed a shift in the abundance of the two arms of mir-US29 between the productive and latency stages of the viral life cycle, suggesting that the star "passenger" form of this microRNA is preferentially expressed during latency. As a whole, our study demonstrates that HCMV expresses during the latency phase, both in vivo and in vitro, only a subset of its microRNAs, which may indicate that they play an important role in maintenance and reactivation of latency. Copyright © 2015 Elsevier B.V. All rights reserved.

Primary display latency criteria based on flying qualities and performance data

NASA Technical Reports Server (NTRS)

Funk, John D., Jr.; Beck, Corin P.; Johns, John B.

1993-01-01

With a pilots' increasing use of visual cue augmentation, much requiring extensive pre-processing, there is a need to establish criteria for new avionics/display design. The timeliness and synchronization of the augmented cues is vital to ensure the performance quality required for precision mission task elements (MTEs) where augmented cues are the primary source of information to the pilot. Processing delays incurred while transforming sensor-supplied flight information into visual cues are unavoidable. Relationships between maximum control system delays and associated flying qualities levels are documented in MIL-F-83300 and MIL-F-8785. While cues representing aircraft status may be just as vital to the pilot as prompt control response for operations in instrument meteorological conditions, presently, there are no specification requirements on avionics system latency. To produce data relating avionics system latency to degradations in flying qualities, the Navy conducted two simulation investigations. During the investigations, flying qualities and performance data were recorded as simulated avionics system latency was varied. Correlated results of the investigation indicates that there is a detrimental impact of latency on flying qualities. Analysis of these results and consideration of key factors influencing their application indicate that: (1) Task performance degrades and pilot workload increases as latency is increased. Inconsistency in task performance increases as latency increases. (2) Latency reduces the probability of achieving Level 1 handling qualities with avionics system latency as low as 70 ms. (3) The data suggest that the achievement of desired performance will be ensured only at display latency values below 120 ms. (4) These data also suggest that avoidance of inadequate performance will be ensured only at display latency values below 150 ms.

RESPONSE LATENCIES OF NORMAL AND FOCAL-HEAD IRRADIATED MONKEYS

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDowell, A.A.; Brown, W.L.

1963-12-01

This study was designed to determine whether focal-head irradiated rhesus monkeys differ from normal monkeys in a manner analogous to that previously found in whole-body irradiated monkeys with respect to response latencies under both familiar and novel stimulus conditions. Five control and four focal-head irradiated rhesus monkeys with nearly identical training histories were used; the latter were survivors of a focal-head irradiation study conducted four years earlier. They had received 3000 r x radiation to the inferior parietal lobule and posterior aspect of the temporal lobe of the brain, and 30 days later the same dosage to the same areamore » of the brain. The testing was conducted in a modified version of the Wisconsin General Test Apparatus, with 24 trials per day for two days, on response latency to a single food-rewarded wooden block placed randomly over either of the two extreme food-well positions. Then, 24 trials were conducted per day for two days on response latency to either the same food-rewarded wooden block or to a novel nonrewarded wooden block presented simultaneously. On the single-block condition, median response latencies of the two groups were comparable and the groups improved in a similar manner with practice. Optimal performance latencies were also comparable for the two groups. When the novel nonrewarded stimulus block was introduced, both groups manifested comparable disruption of median response latencies, but disruption of optimal response latencies was shown only by the focalhead irradiated group. The findings show that monkeys with previous focal-head irradiation of the posterior association areas, unlike relatively high-dose whole-body irradiated monkeys, manifest median response latencies comparable to those of controls. These data indicate the lasting effects of focal-head irradiation with x rays, and suggest that the sites of permanent damage for monkeys given sublethal whole-body radiation exposure differ from the sites

Data latency and the user community

NASA Astrophysics Data System (ADS)

Escobar, V. M.; Brown, M. E.; Carroll, M.

2013-12-01

The community using NASA Earth science observations in applications has grown significantly, with increasing sophistication to serve national interests. The National Research Council's Earth Science Decadal Survey report stated that the planning for applied and operational considerations in the missions should accompany the acquisition of new knowledge about Earth (NRC, 2007). This directive has made product applications at NASA an integral part of converting the data collected into actionable knowledge that can be used to inform policy. However, successfully bridging scientific research with operational decision making in different application areas requires looking into user data requirements and operational needs. This study was conducted to determine how users are incorporating NASA data into applications and operational processes. The approach included a review of published materials, direct interviews with mission representatives, and an online professional review, which was distributed to over 6000 individuals. We provide a complete description of the findings with definitions and explanations of what goes into measuring latency as well as how users and applications utilize NASA data products. We identified 3 classes of users: operational (need data in 3 hours or less), near real time (need data within a day of acquisition), and scientific users (need highest quality data, time independent). We also determined that most users with applications are interested in specific types of products that may come from multiple missions. These users will take the observations when they are available, however the observations may have additional applications value if they are available either by a certain time of day or within a period of time after acquisition. NASA has supported the need for access to low latency data on an ad-hoc basis and more substantively in stand-alone systems such as the MODIS Rapid Response system and more recently with LANCE. The increased level

Latency in Visionic Systems: Test Methods and Requirements

NASA Technical Reports Server (NTRS)

Bailey, Randall E.; Arthur, J. J., III; Williams, Steven P.; Kramer, Lynda J.

2005-01-01

A visionics device creates a pictorial representation of the external scene for the pilot. The ultimate objective of these systems may be to electronically generate a form of Visual Meteorological Conditions (VMC) to eliminate weather or time-of-day as an operational constraint and provide enhancement over actual visual conditions where eye-limiting resolution may be a limiting factor. Empirical evidence has shown that the total system delays or latencies including the imaging sensors and display systems, can critically degrade their utility, usability, and acceptability. Definitions and measurement techniques are offered herein as common test and evaluation methods for latency testing in visionics device applications. Based upon available data, very different latency requirements are indicated based upon the piloting task, the role in which the visionics device is used in this task, and the characteristics of the visionics cockpit display device including its resolution, field-of-regard, and field-of-view. The least stringent latency requirements will involve Head-Up Display (HUD) applications, where the visionics imagery provides situational information as a supplement to symbology guidance and command information. Conversely, the visionics system latency requirement for a large field-of-view Head-Worn Display application, providing a Virtual-VMC capability from which the pilot will derive visual guidance, will be the most stringent, having a value as low as 20 msec.

DART: A Microcomputer Program for Response Latency Analysis.

ERIC Educational Resources Information Center

Greene, John O.; Greene, Barry F.

1987-01-01

Discusses how chronometric measures such as the DART (Display And Response Timing) computer program, have become virtually indispensable in testing cognitive theories of human social behavior. Describes how the DART (1) provides a way to collect response latency data; and (2) allows measurement of response latencies to a set of user-specified,…

Local cochlear damage reduces local nonlinearity and decreases generator-type cochlear emissions while increasing reflector-type emissions.

PubMed

Dong, Wei; Olson, Elizabeth S

2010-03-01

Distortion product otoacoustic emissions (DPOAEs) originate in cochlear nonlinearity and emerge into the ear canal as an apparent sum of emission types, one of which (generator) travels directly out and the other (reflector) travels out following linear reflection. The present study explores intracochlear sources of DPOAEs via simultaneous ear canal and intracochlear pressure measurements in gerbils. A locally damaged cochlea was produced with reduced local intracochlear nonlinearity and significant elevation of the compound action potential thresholds at frequencies represented within the damaged region. In the DPOAE the comparison of healthy to locally damaged cochleae showed the following: (1) In the broad frequency region corresponding to the locally damaged best frequency, DPOAEs evoked by wider f(2)/f(1) stimuli decreased, consistent with the reduction in local nonlinearity. (2) DPOAEs evoked by narrow f(2)/f(1) stimuli often had a bimodal change, decreasing in a lower frequency band and increasing in a band just adjacent and higher, and the DPOAE phase-vs-frequency slope steepened. These changes confirm the complex nature of the DPOAE.

Short- and long-latency auditory evoked potentials in individuals with vestibular dysfunction.

PubMed

Santos Filha, Valdete Alves Valentins Dos; Bruckmann, Mirtes; Garcia, Michele Vargas

2018-01-01

Purpose Evaluate the auditory pathway at the brainstem and cortical levels in individuals with peripheral vestibular dysfunction. Methods The study sample was composed 19 individuals aged 20-80 years that presented exam results suggestive of Peripheral Vestibular Disorder (PVD) or Vestibular Dysfunction (VD). Participants underwent evaluation of the auditory pathway through Brainstem Auditory Evoked Potentials (BAEP) (short latency) and P1, N1, P2, N2, and P300 cortical potentials (long latency). Results Nine individuals presented diagnosis of VD and 10 participants were diagnosed with PVD. The overall average of the long latency potentials of the participants was within the normal range, whereas an increased mean was observed in the short latency of waves III and V of the left ear, as well as in the I - III interpeak interval of both ears. Association of the auditory potentials with VD and PVD showed statistically significant correlation only in the III - V interpeak interval of the right ear for short latency. Comparison between the long and short latencies in the groups showed differences between VD and PVD, but without statistical significance. Conclusion No statistically significant correlation was observed between VD/PVD and the auditory evoked potentials; however, for the long latency potentials, individuals with VD presented higher latency in P1, N1, P2, and N2, where as participants with PVD showed higher latency in P300. In the short latency potentials, there was an increase in the absolute latencies in the VD group and in the interpeak intervals in the PVD group.

Influence of Herpes Simplex Virus 1 Latency-Associated Transcripts on the Establishment and Maintenance of Latency in the ROSA26R Reporter Mouse Model

PubMed Central

Nicoll, M. P.; Proença, J. T.; Connor, V.

2012-01-01

Herpes simplex virus 1 (HSV-1) can establish life-long latent infection in sensory neurons, from which periodic reactivation can occur. During latency, viral gene expression is largely restricted to the latency-associated transcripts (LATs). While not essential for any phase of latency, to date the LATs have been shown to increase the efficiency of both establishment and reactivation of latency in small-animal models. We sought to investigate the role of LAT expression in the frequency of latency establishment within the ROSA26R reporter mouse model utilizing Cre recombinase-encoding recombinant viruses harboring deletions of the core LAT promoter (LAP) region. HSV-1 LAT expression was observed to influence the number of latently infected neurons in trigeminal but not dorsal root ganglia. Furthermore, the relative frequencies of latency establishment of LAT-positive and LAT-negative viruses are influenced by the inoculum dose following infection of the mouse whisker pads. Finally, analysis of the infected cell population at two latent time points revealed a relative loss of latently infected cells in the absence of LAT expression. We conclude that the HSV-1 LATs facilitate the long-term stability of the latent cell population within the infected host and that interpretation of LAT establishment phenotypes is influenced by infection methodology. PMID:22696655

Automatic latency equalization in VHDL-implemented complex pipelined systems

NASA Astrophysics Data System (ADS)

Zabołotny, Wojciech M.

2016-09-01

In the pipelined data processing systems it is very important to ensure that parallel paths delay data by the same number of clock cycles. If that condition is not met, the processing blocks receive data not properly aligned in time and produce incorrect results. Manual equalization of latencies is a tedious and error-prone work. This paper presents an automatic method of latency equalization in systems described in VHDL. The proposed method uses simulation to measure latencies and verify introduced correction. The solution is portable between different simulation and synthesis tools. The method does not increase the complexity of the synthesized design comparing to the solution based on manual latency adjustment. The example implementation of the proposed methodology together with a simple design demonstrating its use is available as an open source project under BSD license.

High-frequency tone burst-evoked ABR latency-intensity functions.

PubMed

Fausti, S A; Olson, D J; Frey, R H; Henry, J A; Schaffer, H I

1993-01-01

High-frequency tone burst stimuli (8, 10, 12, and 14 kHz) have been developed and demonstrated to provide reliable and valid auditory brainstem responses (ABRs) in normal-hearing subjects. In this study, latency-intensity functions (LIFs) were determined using these stimuli in 14 normal-hearing individuals. Significant shifts in response latency occurred as a function of stimulus intensity for all tone burst frequencies. For each 10 dB shift in intensity, latency shifts for waves I and V were statistically significant except for one isolated instance. LIF slopes were comparable between frequencies, ranging from 0.020 to 0.030 msec/dB. These normal LIFs for high-frequency tone burst-evoked ABRs suggest the degree of response latency change that might be expected from, for example, progressive hearing loss due to ototoxic insult, although these phenomena may not be directly related.

Role of microRNAs in herpesvirus latency and persistence.

PubMed

Grey, Finn

2015-04-01

The identification of virally encoded microRNAs (miRNAs) has had a major impact on the field of herpes virology. Given their ability to target cellular and viral transcripts, and the lack of immune response to small RNAs, miRNAs represent an ideal mechanism of gene regulation during viral latency and persistence. In this review, we discuss the role of miRNAs in virus latency and persistence, specifically focusing on herpesviruses. We cover the current knowledge on miRNAs in establishing and maintaining virus latency and promoting survival of infected cells through targeting of both viral and cellular transcripts, highlighting key publications in the field. We also discuss potential areas of future research and how novel technologies may aid in determining how miRNAs shape virus latency in the context of herpesvirus infections. © 2015 The Author.

Test Operations Procedure (TOP) 02-2-546 Teleoperated Unmanned Ground Vehicle (UGV) Latency Measurements

DTIC Science & Technology

2017-01-11

discrete system components or measurements of latency in autonomous systems. 15. SUBJECT TERMS Unmanned Ground Vehicles, Basic Video Latency, End-to... discrete system components or measurements of latency in autonomous systems. 1.1 Basic Video Latency. Teleoperation latency, or lag, describes

The Influence of Non-Nociceptive Factors on Hot Plate Latency in Rats

PubMed Central

Gunn, Amanda; Bobeck, Erin N.; Weber, Ceri; Morgan, Michael M.

2010-01-01

The hot plate is a widely used test to assess nociception. The effect of non-nociceptive factors (weight, sex, activity, habituation, and repeated testing) on hot plate latency was examined. Comparison of body weight and hot plate latency revealed a small but significant inverse correlation (light rats had longer latencies). Habituating rats to the test room for 1 hr prior to testing did not decrease hot plate latency except for female rats tested on Days 2 - 4. Hot plate latency decreased with repeated daily testing, but this was not caused by a decrease in locomotor activity or learning to respond. Activity on the hot plate was consistent across all four trials, and prior exposure to a room temperature plate caused a similar decrease in latency as rats tested repeatedly on the hot plate. Despite this decrease in baseline hot plate latency, there was no difference in morphine antinociceptive potency. The present study shows that weight, habituation to the test room, and repeated testing can alter baseline hot plate latency, but these effects are small and have relatively little impact on morphine antinociception. PMID:20797920

Human embryonic stem cell lines model experimental human cytomegalovirus latency.

PubMed

Penkert, Rhiannon R; Kalejta, Robert F

2013-05-28

Herpesviruses are highly successful pathogens that persist for the lifetime of their hosts primarily because of their ability to establish and maintain latent infections from which the virus is capable of productively reactivating. Human cytomegalovirus (HCMV), a betaherpesvirus, establishes latency in CD34(+) hematopoietic progenitor cells during natural infections in the body. Experimental infection of CD34(+) cells ex vivo has demonstrated that expression of the viral gene products that drive productive infection is silenced by an intrinsic immune defense mediated by Daxx and histone deacetylases through heterochromatinization of the viral genome during the establishment of latency. Additional mechanistic details about the establishment, let alone maintenance and reactivation, of HCMV latency remain scarce. This is partly due to the technical challenges of CD34(+) cell culture, most notably, the difficulty in preventing spontaneous differentiation that drives reactivation and renders them permissive for productive infection. Here we demonstrate that HCMV can establish, maintain, and reactivate in vitro from experimental latency in cultures of human embryonic stem cells (ESCs), for which spurious differentiation can be prevented or controlled. Furthermore, we show that known molecular aspects of HCMV latency are faithfully recapitulated in these cells. In total, we present ESCs as a novel, tractable model for studies of HCMV latency.

Minimizing Input-to-Output Latency in Virtual Environment

NASA Technical Reports Server (NTRS)

Adelstein, Bernard D.; Ellis, Stephen R.; Hill, Michael I.

2009-01-01

A method and apparatus were developed to minimize latency (time delay ) in virtual environment (VE) and other discrete- time computer-base d systems that require real-time display in response to sensor input s. Latency in such systems is due to the sum of the finite time requi red for information processing and communication within and between sensors, software, and displays.

Low-latency situational awareness for UxV platforms

NASA Astrophysics Data System (ADS)

Berends, David C.

2012-06-01

Providing high quality, low latency video from unmanned vehicles through bandwidth-limited communications channels remains a formidable challenge for modern vision system designers. SRI has developed a number of enabling technologies to address this, including the use of SWaP-optimized Systems-on-a-Chip which provide Multispectral Fusion and Contrast Enhancement as well as H.264 video compression. Further, the use of salience-based image prefiltering prior to image compression greatly reduces output video bandwidth by selectively blurring non-important scene regions. Combined with our customization of the VLC open source video viewer for low latency video decoding, SRI developed a prototype high performance, high quality vision system for UxV application in support of very demanding system latency requirements and user CONOPS.

Impact of wave propagation delay on latency in optical communication systems

NASA Astrophysics Data System (ADS)

Kawanishi, Tetsuya; Kanno, Atsushi; Yoshida, Yuki; Kitayama, Ken-ichi

2012-12-01

Latency is an important figure to describe performance of transmission systems for particular applications, such as data transfer for earthquake early warning, transaction for financial businesses, interactive services such as online games, etc. Latency consists of delay due to signal processing at nodes and transmitters, and of signal propagation delay due to propagation of electromagnetic waves. The lower limit of the latency in transmission systems using conventional single mode fibers (SMFs) depends on wave propagation speed in the SMFs which is slower than c. Photonic crystal fibers, holly fibers and large core fibers can have low effective refractive indices, and can transfer light faster than in SMFs. In free-space optical systems, signals propagate with the speed c, so that the latency could be smaller than in optical fibers. For example, LEO satellites would transmit data faster than optical submarine cables, when the transmission distance is longer than a few thousand kilometers. This paper will discuss combination of various transmission media to reduce negative impact of the latency, as well as applications of low-latency systems.

Effects of structured nontarget stimuli on saccadic latency.

PubMed

White, Brian J; Gegenfurtner, Karl R; Kerzel, Dirk

2005-06-01

It has been suggested that the remote distractor effect is the result of nontarget stimulation of a central region representing a collicular fixation zone near the time of target onset. The distributed network of the cells responsible for this effect is believed to extend over a large area, responding to distractors < or =10 deg in the periphery. Several studies also implicate the superior colliculus as the substrate behind an inhibited saccadic response arising from a display change. We investigated this further by using a patch of pink noise of various sizes as a nontarget stimulus. We show that the onset of a small patch (2.3 x 2.3 deg) of centrally displayed pink noise can produce a significant increase in saccadic latency to a simultaneously presented peripheral Gabor target. In contrast, a large patch (36 x 36 deg) of pink noise did not increase latency despite the fact that it also stimulated the region representing the fixation zone. Furthermore, only the large patch of noise facilitated latency when presented before target onset. We also examined the effect of patch sizes between these two extremes and found a steady decrease in latency as patch size increased. This confirms that nontarget stimulation of the region representing the fixation zone near the time of target onset is not in itself sufficient to produce the increase in latency typically found with remote distractors. The results are consistent with the idea that only a spatially confined object leads to a discharge of collicular fixation neurons.

The influence of non-nociceptive factors on hot-plate latency in rats.

PubMed

Gunn, Amanda; Bobeck, Erin N; Weber, Ceri; Morgan, Michael M

2011-02-01

The hot plate is a widely used test to assess nociception. The effect of non-nociceptive factors (weight, sex, activity, habituation, and repeated testing) on hot-plate latency was examined. Comparison of body weight and hot-plate latency revealed a small but significant inverse correlation (light rats had longer latencies). Habituating rats to the test room for 1 hour prior to testing did not decrease hot-plate latency except for female rats tested on days 2 to 4. Hot-plate latency decreased with repeated daily testing, but this was not caused by a decrease in locomotor activity or learning to respond. Activity on the hot plate was consistent across all 4 trials, and prior exposure to a room-temperature plate caused a similar decrease in latency as rats tested repeatedly on the hot plate. Despite this decrease in baseline hot-plate latency, there was no difference in morphine antinociceptive potency. The present study shows that weight, habituation to the test room, and repeated testing can alter baseline hot-plate latency, but these effects are small and have relatively little impact on morphine antinociception. This manuscript shows that non-nociceptive factors such as body weight, habituation, and repeated testing can alter hot-plate latency, but these factors do not alter morphine potency. In sum, the hot-plate test is an easy to use and reliable method to assess supraspinally organized nociceptive responses. Copyright © 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.

Cumulative latency advance underlies fast visual processing in desynchronized brain state

PubMed Central

Wang, Xu-dong; Chen, Cheng; Zhang, Dinghong; Yao, Haishan

2014-01-01

Fast sensory processing is vital for the animal to efficiently respond to the changing environment. This is usually achieved when the animal is vigilant, as reflected by cortical desynchronization. However, the neural substrate for such fast processing remains unclear. Here, we report that neurons in rat primary visual cortex (V1) exhibited shorter response latency in the desynchronized state than in the synchronized state. In vivo whole-cell recording from the same V1 neurons undergoing the two states showed that both the resting and visually evoked conductances were higher in the desynchronized state. Such conductance increases of single V1 neurons shorten the response latency by elevating the membrane potential closer to the firing threshold and reducing the membrane time constant, but the effects only account for a small fraction of the observed latency advance. Simultaneous recordings in lateral geniculate nucleus (LGN) and V1 revealed that LGN neurons also exhibited latency advance, with a degree smaller than that of V1 neurons. Furthermore, latency advance in V1 increased across successive cortical layers. Thus, latency advance accumulates along various stages of the visual pathway, likely due to a global increase of membrane conductance in the desynchronized state. This cumulative effect may lead to a dramatic shortening of response latency for neurons in higher visual cortex and play a critical role in fast processing for vigilant animals. PMID:24347634

Cumulative latency advance underlies fast visual processing in desynchronized brain state.

PubMed

Wang, Xu-dong; Chen, Cheng; Zhang, Dinghong; Yao, Haishan

2014-01-07

Fast sensory processing is vital for the animal to efficiently respond to the changing environment. This is usually achieved when the animal is vigilant, as reflected by cortical desynchronization. However, the neural substrate for such fast processing remains unclear. Here, we report that neurons in rat primary visual cortex (V1) exhibited shorter response latency in the desynchronized state than in the synchronized state. In vivo whole-cell recording from the same V1 neurons undergoing the two states showed that both the resting and visually evoked conductances were higher in the desynchronized state. Such conductance increases of single V1 neurons shorten the response latency by elevating the membrane potential closer to the firing threshold and reducing the membrane time constant, but the effects only account for a small fraction of the observed latency advance. Simultaneous recordings in lateral geniculate nucleus (LGN) and V1 revealed that LGN neurons also exhibited latency advance, with a degree smaller than that of V1 neurons. Furthermore, latency advance in V1 increased across successive cortical layers. Thus, latency advance accumulates along various stages of the visual pathway, likely due to a global increase of membrane conductance in the desynchronized state. This cumulative effect may lead to a dramatic shortening of response latency for neurons in higher visual cortex and play a critical role in fast processing for vigilant animals.

Construction and Evaluation of an Ultra Low Latency Frameless Renderer for VR.

PubMed

Friston, Sebastian; Steed, Anthony; Tilbury, Simon; Gaydadjiev, Georgi

2016-04-01

Latency - the delay between a user's action and the response to this action - is known to be detrimental to virtual reality. Latency is typically considered to be a discrete value characterising a delay, constant in time and space - but this characterisation is incomplete. Latency changes across the display during scan-out, and how it does so is dependent on the rendering approach used. In this study, we present an ultra-low latency real-time ray-casting renderer for virtual reality, implemented on an FPGA. Our renderer has a latency of ~1 ms from 'tracker to pixel'. Its frameless nature means that the region of the display with the lowest latency immediately follows the scan-beam. This is in contrast to frame-based systems such as those using typical GPUs, for which the latency increases as scan-out proceeds. Using a series of high and low speed videos of our system in use, we confirm its latency of ~1 ms. We examine how the renderer performs when driving a traditional sequential scan-out display on a readily available HMO, the Oculus Rift OK2. We contrast this with an equivalent apparatus built using a GPU. Using captured human head motion and a set of image quality measures, we assess the ability of these systems to faithfully recreate the stimuli of an ideal virtual reality system - one with a zero latency tracker, renderer and display running at 1 kHz. Finally, we examine the results of these quality measures, and how each rendering approach is affected by velocity of movement and display persistence. We find that our system, with a lower average latency, can more faithfully draw what the ideal virtual reality system would. Further, we find that with low display persistence, the sensitivity to velocity of both systems is lowered, but that it is much lower for ours.

Glomerular latency coding in artificial olfaction.

PubMed

Yamani, Jaber Al; Boussaid, Farid; Bermak, Amine; Martinez, Dominique

2011-01-01

Sensory perception results from the way sensory information is subsequently transformed in the brain. Olfaction is a typical example in which odor representations undergo considerable changes as they pass from olfactory receptor neurons (ORNs) to second-order neurons. First, many ORNs expressing the same receptor protein yet presenting heterogeneous dose-response properties converge onto individually identifiable glomeruli. Second, onset latency of glomerular activation is believed to play a role in encoding odor quality and quantity in the context of fast information processing. Taking inspiration from the olfactory pathway, we designed a simple yet robust glomerular latency coding scheme for processing gas sensor data. The proposed bio-inspired approach was evaluated using an in-house SnO(2) sensor array. Glomerular convergence was achieved by noting the possible analogy between receptor protein expressed in ORNs and metal catalyst used across the fabricated gas sensor array. Ion implantation was another technique used to account both for sensor heterogeneity and enhanced sensitivity. The response of the gas sensor array was mapped into glomerular latency patterns, whose rank order is concentration-invariant. Gas recognition was achieved by simply looking for a "match" within a library of spatio-temporal spike fingerprints. Because of its simplicity, this approach enables the integration of sensing and processing onto a single-chip.

Defining the Transcriptional Landscape during Cytomegalovirus Latency with Single-Cell RNA Sequencing

PubMed Central

2018-01-01

ABSTRACT Primary infection with human cytomegalovirus (HCMV) results in a lifelong infection due to its ability to establish latent infection, with one characterized viral reservoir being hematopoietic cells. Although reactivation from latency causes serious disease in immunocompromised individuals, our molecular understanding of latency is limited. Here, we delineate viral gene expression during natural HCMV persistent infection by analyzing the massive transcriptome RNA sequencing (RNA-seq) atlas generated by the Genotype-Tissue Expression (GTEx) project. This systematic analysis reveals that HCMV persistence in vivo is prevalent in diverse tissues. Notably, we find only viral transcripts that resemble gene expression during various stages of lytic infection with no evidence of any highly restricted latency-associated viral gene expression program. To further define the transcriptional landscape during HCMV latent infection, we also used single-cell RNA-seq and a tractable experimental latency model. In contrast to some current views on latency, we also find no evidence for any highly restricted latency-associated viral gene expression program. Instead, we reveal that latency-associated gene expression largely mirrors a late lytic viral program, albeit at much lower levels of expression. Overall, our work has the potential to revolutionize our understanding of HCMV persistence and suggests that latency is governed mainly by quantitative changes, with a limited number of qualitative changes, in viral gene expression. PMID:29535194

Fault latency in the memory - An experimental study on VAX 11/780

NASA Technical Reports Server (NTRS)

Chillarege, Ram; Iyer, Ravishankar K.

1986-01-01

Fault latency is the time between the physical occurrence of a fault and its corruption of data, causing an error. The measure of this time is difficult to obtain because the time of occurrence of a fault and the exact moment of generation of an error are not known. This paper describes an experiment to accurately study the fault latency in the memory subsystem. The experiment employs real memory data from a VAX 11/780 at the University of Illinois. Fault latency distributions are generated for s-a-0 and s-a-1 permanent fault models. Results show that the mean fault latency of a s-a-0 fault is nearly 5 times that of the s-a-1 fault. Large variations in fault latency are found for different regions in memory. An analysis of a variance model to quantify the relative influence of various workload measures on the evaluated latency is also given.

Low-Latency Lunar Surface Telerobotics from Earth-Moon Libration Points

NASA Technical Reports Server (NTRS)

Lester, Daniel; Thronson, Harley

2011-01-01

Concepts for a long-duration habitat at Earth-Moon LI or L2 have been advanced for a number of purposes. We propose here that such a facility could also have an important role for low-latency telerobotic control of lunar surface equipment, both for lunar science and development. With distances of about 60,000 km from the lunar surface, such sites offer light-time limited two-way control latencies of order 400 ms, making telerobotic control for those sites close to real time as perceived by a human operator. We point out that even for transcontinental teleoperated surgical procedures, which require operational precision and highly dexterous manipulation, control latencies of this order are considered adequate. Terrestrial telerobots that are used routinely for mining and manufacturing also involve control latencies of order several hundred milliseconds. For this reason, an Earth-Moon LI or L2 control node could build on the technology and experience base of commercially proven terrestrial ventures. A lunar libration-point telerobotic node could demonstrate exploration strategies that would eventually be used on Mars, and many other less hospitable destinations in the solar system. Libration-point telepresence for the Moon contrasts with lunar telerobotic control from the Earth, for which two-way control latencies are at least six times longer. For control latencies that long, telerobotic control efforts are of the "move-and-wait" variety, which is cognitively inferior to near real-time control.

Optimizing latency in Xilinx FPGA implementations of the GBT

NASA Astrophysics Data System (ADS)

Muschter, S.; Baron, S.; Bohm, C.; Cachemiche, J.-P.; Soos, C.

2010-12-01

The GigaBit Transceiver (GBT) [1] system has been developed to replace the Timing, Trigger and Control (TTC) system [2], currently used by LHC, as well as to provide data transmission between on-detector and off-detector components in future sLHC detectors. A VHDL version of the GBT-SERDES, designed for FPGAs, was released in March 2010 as a GBT-FPGA Starter Kit for future GBT users and for off-detector GBT implementation [3]. This code was optimized for resource utilization [4], as the GBT protocol is very demanding. It was not, however, optimized for latency — which will be a critical parameter when used in the trigger path. The GBT-FPGA Starter Kit firmware was first analyzed in terms of latency by looking at the separate components of the VHDL version. Once the parts which contribute most to the latency were identified and modified, two possible optimizations were chosen, resulting in a latency reduced by a factor of three. The modifications were also analyzed in terms of logic utilization. The latency optimization results were compared with measurement results from a Virtex 6 ML605 development board [5] equipped with a XC6VLX240T with speedgrade-1 and the package FF1156. Bit error rate tests were also performed to ensure an error free operation. The two final optimizations were analyzed for utilization and compared with the original code, distributed in the Starter Kit.

Low-Latency Science Exploration of Planetary Bodies: How ISS Might Be Used as Part of a Low-Latency Analog Campaign for Human Exploration

NASA Technical Reports Server (NTRS)

Thronson, Harley; Valinia, Azita; Bleacher, Jacob; Eigenbrode, Jennifer; Garvin, Jim; Petro, Noah

2014-01-01

We suggest that the International Space Station be used to examine the application and validation of low-latency telepresence for surface exploration from space as an alternative, precursor, or potentially as an adjunct to astronaut "boots on the ground." To this end, controlled experiments that build upon and complement ground-based analog field studies will be critical for assessing the effects of different latencies (0 to 500 milliseconds), task complexity, and alternate forms of feedback to the operator. These experiments serve as an example of a pathfinder for NASA's roadmap of missions to Mars with low-latency telerobotic exploration as a precursor to astronaut's landing on the surface to conduct geological tasks.

[Upper-limb work-related musculoskeletal disorders (UL-WMSDs) and latency of effect].

PubMed

Nicoletti, S; Battevi, N

2008-01-01

Trends in work-related upper limb musculoskeletal disorders appear to be in constant increase in industrialized countries. In Europe claims and compensation for these disorders have significantly increased. The aim of this study was to investigate the temporal relationship between the beginning of occupational exposure to repetitive movements and exertions of upper limbs, assessed through the OCRA index, and the manifestation of the disorders. Clinical and questionnaire information about 557 cases of UL-WMSDs in the upholstered furniture industry were analyzed in order to investigate the mean latency period of the disorders and to verify to what extent different levels of exposure influence the latency time. The latency of UL-WMSDs is influenced by the level of exposure to risk, measured by means of the OCRA index. Shorter latency times were found for wrist/hand tendonitis, with a mean latency time of 5.4 years and with a greater sensitivity to the level of exposure assessed with the OCRA index value. This might support a sort of predictive value with reference to other UL-WMSDs with longer latency. Probably a latency period of 12 years may be suggested as the cut-off limit to assess a causal relationship between tendon or canalicular WMISDs and occupational exposure to repetitive movements and exertions of upper limbs.

Fault and Error Latency Under Real Workload: an Experimental Study. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Chillarege, Ram

1986-01-01

A practical methodology for the study of fault and error latency is demonstrated under a real workload. This is the first study that measures and quantifies the latency under real workload and fills a major gap in the current understanding of workload-failure relationships. The methodology is based on low level data gathered on a VAX 11/780 during the normal workload conditions of the installation. Fault occurrence is simulated on the data, and the error generation and discovery process is reconstructed to determine latency. The analysis proceeds to combine the low level activity data with high level machine performance data to yield a better understanding of the phenomena. A strong relationship exists between latency and workload and that relationship is quantified. The sampling and reconstruction techniques used are also validated. Error latency in the memory where the operating system resides was studied using data on the physical memory access. Fault latency in the paged section of memory was determined using data from physical memory scans. Error latency in the microcontrol store was studied using data on the microcode access and usage.

Using Stimulus Frequency Emissions to Characterize Cochlear Function in Mice

NASA Astrophysics Data System (ADS)

Cheatham, M. A.; Katz, E. D.; Charaziak, K.; Dallos, P.; Siegel, J. H.

2011-11-01

Stimulus frequency otoacoustic emissions (SFOAE) were used to assay cochlear function in wildtype and prestin knockin (KI) mice. The latter contain a mutated form of the outer hair cell (OHC) motor protein (V499G/Y501H) with significantly reduced activity. Because several genetic mutations cause accelerated OHC death, it is beneficial to perform experiments in young mice without surgical intervention. Inasmuch as SFOAE thresholds are elevated by only 30 dB in KIs, it is possible to obtain SFOAE tuning functions in these animals. This approach allows sensitivity/frequency selectivity to be assayed within the basilar membane-OHC-tectorial membrane feedback loop, thereby providing information about signal processing prior to inner hair cell stimulation and auditory nerve activation.

Research on low-latency MAC protocols for wireless sensor networks

NASA Astrophysics Data System (ADS)

He, Chenguang; Sha, Xuejun; Lee, Chankil

2007-11-01

Energy-efficient should not be the only design goal in MAC protocols for wireless sensor networks, which involve the use of battery-operated computing and sensing devices. Low-latency operation becomes the same important as energy-efficient in the case that the traffic load is very heavy or the real-time constrain is used in applications like tracking or locating. This paper introduces some causes of traditional time delays which are inherent in a multi-hops network using existing WSN MAC protocols, illuminates the importance of low-latency MAC design for wireless sensor networks, and presents three MACs as examples of low-latency protocols designed specially for sleep delay, wait delay and wakeup delay in wireless sensor networks, respectively. The paper also discusses design trade-offs with emphasis on low-latency and points out their advantages and disadvantages, together with some design considerations and suggestions for MAC protocols for future applications and researches.

Multiple sleep latency measures in narcolepsy and behaviourally induced insufficient sleep syndrome.

PubMed

Marti, Isabelle; Valko, Philipp O; Khatami, Ramin; Bassetti, Claudio L; Baumann, Christian R

2009-12-01

Short mean latencies to the first epoch of non-rapid eye movement sleep stage 1 (NREM1) and the presence of >or= 2 sleep onset REM (SOREM) periods on multiple sleep latency test (MSLT) occur in both narcolepsy-cataplexy (NC) and behaviourally induced insufficient sleep syndrome (BIISS). It is not known whether specific MSLT findings help differentiate the two disorders. We analyzed MSLT data including sleep latencies to and between different sleep stages of 60 age-, gender- and body mass index (BMI)-matched subjects (hypocretin-deficient NC, actigraphy-confirmed BIISS, healthy controls: each 20). Mean latency (in minutes) to NREM1 sleep was significantly shorter in NC (1.8+/-1.5) than in BIISS (4.7+/-2.1, p<0.001) and controls (11.4+/-3.3, p<0.001). Mean latency to NREM2 sleep was similar in NC (8.6+/-4.7) and BIISS (8.1+/-2.7, p=0.64); latency to either NREM2 or rapid eye movement (REM) sleep (i.e., the sum of the sleep latency to NREM1 and the duration of the first NREM1 sleep sequence), however, was shorter in NC (4.4+/-2.9) than in BIISS (7.9+/-3.5, p<0.001). Referring to all naps with SOREM periods, the sequence NREM1-REM-NREM2 was more common (71%) in NC than in BIISS (15%, p<0.001), reflecting the shorter latency from NREM1 to NREM2 in BIISS (3.7+/-2.5) than in NC (6.1+/-5.9, p<0.001). Our findings show that both sleepiness (as measured by NREM1 sleep latency) and REM sleep propensity are higher in NC than in BIISS. Furthermore, our finding of frequent REM sleep prior to NREM2 sleep in NC is in line with the recent assumption of an insufficient NREM sleep intensity in NC. Together with detailed clinical interviews, sleep logs, actigraphy, and nocturnal polysomnography, mean sleep latencies to NREM1

On the influence of latency estimation on dynamic group communication using overlays

NASA Astrophysics Data System (ADS)

Vik, Knut-Helge; Griwodz, Carsten; Halvorsen, Pål

2009-01-01

Distributed interactive applications tend to have stringent latency requirements and some may have high bandwidth demands. Many of them have also very dynamic user groups for which all-to-all communication is needed. In online multiplayer games, for example, such groups are determined through region-of-interest management in the application. We have investigated a variety of group management approaches for overlay networks in earlier work and shown that several useful tree heuristics exist. However, these heuristics require full knowledge of all overlay link latencies. Since this is not scalable, we investigate the effects that latency estimation techqniues have ton the quality of overlay tree constructions. We do this by evaluating one example of our group management approaches in Planetlab and examing how latency estimation techqniues influence their quality. Specifically, we investigate how two well-known latency estimation techniques, Vivaldi and Netvigator, affect the quality of tree building.

Role of Active Listening and Listening Effort on Contralateral Suppression of Transient Evoked Otoacousic Emissions.

PubMed

Kalaiah, Mohan Kumar; Theruvan, Nikhitha B; Kumar, Kaushlendra; Bhat, Jayashree S

2017-04-01

The present study aimed to investigate the effect of active listening and listening effort on the contralateral suppression of transient evoked otoacoustic emissions (CSTEOAEs). Twenty eight young adults participated in the study. Transient evoked otoacoustic emissions (TEOAEs) were recorded using 'linear' clicks at 60 dB peSPL, in three contralateral noise conditions. In condition 1, TEOAEs were obtained in the presence of white noise in the contralateral ear. While, in condition 2, speech was embedded into white noise at +3, -3, and -9 dB signal-to-noise ratio (SNR) and delivered to the contralateral ear. The SNR was varied to investigate the effect of listening effort on the CSTEOAE. In condition 3, speech was played backwards and embedded into white noise at -3 dB SNR. The conditions 1 and 3 served as passive listening condition and the condition 2 served as active listening condition. In active listening condition, the participants categorized the words in to two groups (e.g., animal and vehicle). CSTEOAE was found to be largest in the presence of white noise, and the amount of CSTEOAE was not significantly different between active and passive listening conditions (condition 2 and 3). Listening effort had an effect on the CSTEOAE, the amount of suppression increased with listening effort, when SNR was decreased from +3 dB to -3 dB. However, when the SNR was further reduced to -9 dB, there was no further increase in the amount of CSTEOAE, instead there was a reduction in the amount of suppression. The findings of the present study show that listening effort might affect CSTEOAE.

Latency correction of event-related potentials between different experimental protocols

NASA Astrophysics Data System (ADS)

Iturrate, I.; Chavarriaga, R.; Montesano, L.; Minguez, J.; Millán, JdR

2014-06-01

Objective. A fundamental issue in EEG event-related potentials (ERPs) studies is the amount of data required to have an accurate ERP model. This also impacts the time required to train a classifier for a brain-computer interface (BCI). This issue is mainly due to the poor signal-to-noise ratio and the large fluctuations of the EEG caused by several sources of variability. One of these sources is directly related to the experimental protocol or application designed, and may affect the amplitude or latency of ERPs. This usually prevents BCI classifiers from generalizing among different experimental protocols. In this paper, we analyze the effect of the amplitude and the latency variations among different experimental protocols based on the same type of ERP. Approach. We present a method to analyze and compensate for the latency variations in BCI applications. The algorithm has been tested on two widely used ERPs (P300 and observation error potentials), in three experimental protocols in each case. We report the ERP analysis and single-trial classification. Main results. The results obtained show that the designed experimental protocols significantly affect the latency of the recorded potentials but not the amplitudes. Significance. These results show how the use of latency-corrected data can be used to generalize the BCIs, reducing the calibration time when facing a new experimental protocol.

Validation of a noninvasive test routinely used in otology for the diagnosis of cerebrospinal fluid shunt malfunction in patients with normal pressure hydrocephalus.

PubMed

Sakka, Laurent; Chomicki, Alexandre; Gabrillargues, Jean; Khalil, Toufic; Chazal, Jean; Avan, Paul

2016-02-01

Ventriculoperitoneal shunting is the first-line treatment for normal pressure hydrocephalus. Noninvasive auditory tests based on recorded otoacoustic emissions were assessed, as currently used for universal neonatal hearing screenings, for the diagnosis of cerebrospinal fluid shunt malfunction. The test was designed based on previous works, which demonstrated that an intracranial pressure change induces a proportional, characteristic, otoacoustic-emission phase shift. Forty-four patients with normal pressure hydrocephalus (23 idiopathic and 21 secondary cases) were included in this prospective observational study. The male:female sex ratio was 1.44, the age range was 21-87 years (mean age 64.3 years), and the range of the follow-up period was 1-3 years (mean 20 months). Patients were implanted with a Sophy SU8 adjustable-pressure valve as the ventriculoperitoneal shunt. The phase shifts of otoacoustic emissions in response to body tilt were measured preoperatively, immediately postoperatively, and at 3-6 months, 7-15 months, 16-24 months, and more than 24 months postoperatively. Three groups were enrolled: Group 1, 19 patients who required no valve opening-pressure adjustment; Group 2, 18 patients who required valve opening-pressure adjustments; and Group 3, 7 patients who required valve replacement. In Group 1, phase shift, which was positive before surgery, became steadily negative after surgery and during the follow-up. In Group 2, phase shift, which was positive before surgery, became negative immediately after surgery and increasingly negative after a decrease in the valve-opening pressure. In Group 3, phase shift was positive in 6 cases and slightly negative in 1 case before revision, but after revision phase shift became significantly negative in all cases. Otoacoustic emissions noninvasively reflect cerebrospinal fluid shunt function and are impacted by valve-opening pressure adjustments. Otoacoustic emissions consistently diagnosed shunt malfunction and

Modelling Transposition Latencies: Constraints for Theories of Serial Order Memory

ERIC Educational Resources Information Center

Farrell, Simon; Lewandowsky, Stephan

2004-01-01

Several competing theories of short-term memory can explain serial recall performance at a quantitative level. However, most theories to date have not been applied to the accompanying pattern of response latencies, thus ignoring a rich and highly diagnostic aspect of performance. This article explores and tests the error latency predictions of…

The effect of monitor raster latency on VEPs, ERPs and Brain-Computer Interface performance.

PubMed

Nagel, Sebastian; Dreher, Werner; Rosenstiel, Wolfgang; Spüler, Martin

2018-02-01

Visual neuroscience experiments and Brain-Computer Interface (BCI) control often require strict timings in a millisecond scale. As most experiments are performed using a personal computer (PC), the latencies that are introduced by the setup should be taken into account and be corrected. As a standard computer monitor uses a rastering to update each line of the image sequentially, this causes a monitor raster latency which depends on the position, on the monitor and the refresh rate. We technically measured the raster latencies of different monitors and present the effects on visual evoked potentials (VEPs) and event-related potentials (ERPs). Additionally we present a method for correcting the monitor raster latency and analyzed the performance difference of a code-modulated VEP BCI speller by correcting the latency. There are currently no other methods validating the effects of monitor raster latency on VEPs and ERPs. The timings of VEPs and ERPs are directly affected by the raster latency. Furthermore, correcting the raster latency resulted in a significant reduction of the target prediction error from 7.98% to 4.61% and also in a more reliable classification of targets by significantly increasing the distance between the most probable and the second most probable target by 18.23%. The monitor raster latency affects the timings of VEPs and ERPs, and correcting resulted in a significant error reduction of 42.23%. It is recommend to correct the raster latency for an increased BCI performance and methodical correctness. Copyright © 2017 Elsevier B.V. All rights reserved.

Communication latencies of wireless devices suitable for time-critical messaging to anesthesia providers.

PubMed

Epstein, Richard H; Dexter, Franklin; Rothman, Brian

2013-04-01

Rapid and reliable methods of text communication to mobile anesthesia care providers are important to patient care and to efficient operating room management. Anesthesia departments are implementing automated methods to send text messages to mobile devices for abnormal vital signs, clinical recommendations, quality of care, and compliance or billing issues. The most time-critical communications determine maximum acceptable latencies. We studied the reliability of several alphanumeric messaging systems to identify an appropriate technology for such use. Latencies between message initiation and delivery to 3 alphanumeric paging devices were measured over weeks. Two devices used Internet pathways outside the hospital's local network with an external paging vendor (SkyTel). The third device used only the internal hospital network (Zetron). Sequential cell phone text page latencies were examined for lag-1 autocorrelation using the runs test, with results binned by hour and by day. Message latencies subsequently were batched in successive 1-week bins for calculation of the mean and 99th percentiles of latencies. We defined acceptance criteria as a mean latency <30 seconds and no more than 1 in 200 pages (0.5%) having a latency longer than 100 seconds. Cell phone texting was used as a positive control to assure that the analysis was appropriate, because such devices have (known) poor reliability during high network activity. There was substantial correlation among latencies for sequential cell phone text messages when binned by hours (P < 0.0001), but not by days (P = 0.61). The 2 devices using Internet pathways outside the hospital's network demonstrated unacceptable performance, with 1.3% and 33% of latencies exceeding 100 seconds, respectively. The device dependent only on the internal network had a mean latency of 8 seconds, with 100% of 40,200 pages having latencies <100 seconds. The findings suggest that the network used was the deciding factor. Developers of

Arbitration in crossbar interconnect for low latency

DOEpatents

Ohmacht, Martin; Sugavanam, Krishnan

2013-02-05

A system and method and computer program product for reducing the latency of signals communicated through a crossbar switch, the method including using at slave arbitration logic devices associated with Slave devices for which access is requested from one or more Master devices, two or more priority vector signals cycled among their use every clock cycle for selecting one of the requesting Master devices and updates the respective priority vector signal used every clock cycle. Similarly, each Master for which access is requested from one or more Slave devices, can have two or more priority vectors and can cycle among their use every clock cycle to further reduce latency and increase throughput performance via the crossbar.

Reversal of Latency as Part of a Cure for HIV-1.

PubMed

Rasmussen, Thomas Aagaard; Tolstrup, Martin; Søgaard, Ole Schmeltz

2016-02-01

Here, the use of pharmacological agents to reverse HIV-1 latency will be explored as a therapeutic strategy towards a cure. However, while clinical trials of latency-reversing agents LRAs) have demonstrated their ability to increase production of latent HIV-1, such interventions have not had an effect on the size of the latent HIV-1 reservoir. Plausible explanations for this include insufficient host immune responses against virus-expressing cells, the presence of escape mutations in archived virus, or an insufficient scale of latency reversal. Importantly, these early studies of LRAs were primarily designed to investigate their ability to perturb the state of HIV-1 latency; using the absence of an impact on the size of the HIV-1 reservoir to discard their potential inclusion in curative strategies would be erroneous and premature. Copyright © 2015 Elsevier Ltd. All rights reserved.

Medial olivocochlear function in children with poor speech-in-noise performance and language disorder.

PubMed

Rocha-Muniz, Caroline Nunes; Mamede Carvallo, Renata Mota; Schochat, Eliane

2017-05-01

Contralateral masking of transient-evoked otoacoustic emissions is a phenomenon that suggests an inhibitory effect of the olivocochlear efferent auditory pathway. Many studies have been inconclusive in demonstrating a clear connection between this system and a behavioral speech-in-noise listening skill. The purpose of this study was to investigate the activation of a medial olivocochlear (MOC) efferent in children with poor speech-in-noise (PSIN) performance and children with language impairment and PSIN (SLI + PSIN). Transient evoked otoacoustic emissions (TEOAEs) with and without contralateral white noise were tested in 52 children (between 6 and 12 years). These children were arranged in three groups: typical development (TD) (n = 25), PSIN (n = 14) and SLI + PSI (n = 13). PSIN and SLI + PSI groups presented reduced otoacoustic emission suppression in comparison with the TD group. Our finding suggests differences in MOC function among children with typical development and children with poor SIN and language problems. Copyright © 2017 Elsevier B.V. All rights reserved.

[Effects of acute infrasound exposure on vestibular and auditory functions and the ultrastructural changes of inner ear in the guinea pig].

PubMed

Feng, B; Jiang, S; Yang, W; Han, D; Zhang, S

2001-02-01

To define the effects of acute infrasound exposure on vestibular and auditory functions and the ultrastructural changes of inner ear in guinea pigs. The animals involved in the study were exposed to 8 Hz infrasound at 135dB SPL for 90 minutes in a reverberant chamber. The sinusoidal pendular test (SPT), auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) were respectively detected pre-exposure and at 0(within 2 hrs), 2 and 5 day after exposure. The ultrastructures of the inner ear were observed by scanning electron microscopy. The slow-phase velocity and the frequency of the vestibular nystagmus elicited by sinusoidal pendular test (SPT) declined slightly following infrasound exposure, but the changes were not significant (P > 0.05). No differences in the ABR thresholds, the latencies and the interval peak latencies of I, III, V waves were found between the normal and the experimental groups, and among experimental groups. The amplitudes of DPOAE at any frequency declined remarkably in all experimental groups. The ultrastructures of the inner ear were damaged to different extent. Infrasound could transiently depress the excitability of the vestibular end-organs, decrease the function of OHC in the organ of Corti and cause damage to the inner ear of guinea pigs.

Simulation Based Studies of Low Latency Teleoperations for NASA Exploration Missions

NASA Technical Reports Server (NTRS)

Gernhardt, Michael L.; Crues, Edwin Z.; Bielski, Paul; Dexter, Dan; Litaker, Harry L.; Chappell, Steven P.; Beaton, Kara H.; Bekdash, Omar S.

2017-01-01

Human exploration of Mars will involve both crewed and robotic systems. Many mission concepts involve the deployment and assembly of mission support assets prior to crew arrival on the surface. Some of these deployment and assembly activities will be performed autonomously while others will be performed using teleoperations. However, significant communications latencies between the Earth and Mars make teleoperations challenging. Alternatively, low latency teleoperations are possible from locations in Mars orbit like Mars' moons Phobos and Deimos. To explore these latency opportunities, NASA is conducting a series of studies to investigate the effects of latency on telerobotic deployment and assembly activities. These studies are being conducted in laboratory environments at NASA's Johnson Space Center (JSC), the Human Exploration Research Analog (HERA) at JSC and the NASA Extreme Environment Mission Operations (NEEMO) underwater habitat off the coast of Florida. The studies involve two human-in-the-loop interactive simulations developed by the NASA Exploration Systems Simulations (NExSyS) team at JSC. The first simulation investigates manipulation related activities while the second simulation investigates mobility related activities. The first simulation provides a simple real-time operator interface with displays and controls for a simulated 6 degree of freedom end effector. The initial version of the simulation uses a simple control mode to decouple the robotic kinematic constraints and a communications delay to model latency effects. This provides the basis for early testing with more detailed manipulation simulations planned for the future. Subjects are tested using five operating latencies that represent teleoperation conditions from local surface operations to orbital operations at Phobos, Deimos and ultimately high Martian orbit. Subject performance is measured and correlated with three distance-to-target zones of interest. Each zone represents a target

Modeling HSV-1 Latency in Human Embryonic Stem Cell-Derived Neurons

PubMed Central

Pourchet, Aldo; Modrek, Aram S.; Placantonakis, Dimitris G.; Mohr, Ian; Wilson, Angus C.

2017-01-01

Herpes simplex virus 1 (HSV-1) uses latency in peripheral ganglia to persist in its human host, however, recurrent reactivation from this reservoir can cause debilitating and potentially life-threatening disease. Most studies of latency use live-animal infection models, but these are complex, multilayered systems and can be difficult to manipulate. Infection of cultured primary neurons provides a powerful alternative, yielding important insights into host signaling pathways controlling latency. However, small animal models do not recapitulate all aspects of HSV-1 infection in humans and are limited in terms of the available molecular tools. To address this, we have developed a latency model based on human neurons differentiated in culture from an NIH-approved embryonic stem cell line. The resulting neurons are highly permissive for replication of wild-type HSV-1, but establish a non-productive infection state resembling latency when infected at low viral doses in the presence of the antivirals acyclovir and interferon-α. In this state, viral replication and expression of a late viral gene marker are not detected but there is an accumulation of the viral latency-associated transcript (LAT) RNA. After a six-day establishment period, antivirals can be removed and the infected cultures maintained for several weeks. Subsequent treatment with sodium butyrate induces reactivation and production of new infectious virus. Human neurons derived from stem cells provide the appropriate species context to study this exclusively human virus with the potential for more extensive manipulation of the progenitors and access to a wide range of preexisting molecular tools. PMID:28594343

Saccade Latency Indexes Exogenous and Endogenous Object-Based Attention

PubMed Central

Şentürk, Gözde; Greenberg, Adam S.; Liu, Taosheng

2016-01-01

Classic studies of object-based attention have utilized keypress responses as the main dependent measure. However, people typically make saccades to fixate important objects. Recent work has shown that attention may act differently when deployed covertly versus in advance of a saccade. We further investigated the link between saccades and attention by examining whether object-based effects can be observed for saccades. We adapted the classical double-rectangle cueing paradigm of Egly et al., (1994), and measured both the first saccade latency and keypress reaction time (RT) to a target that appeared at the end of one of the two rectangles. Our results showed that saccade latency exhibited higher sensitivity than RT in detecting effects of attention. We also assessed the generality of the attention effects by testing three types of cues: hybrid (predictive and peripheral), exogenous (non-predictive and peripheral), and endogenous (predictive and central). We found that both RT and saccade latency exhibited effects of both space-based and object-based attentional selection. However, saccade latency showed a more robust attentional modulation than RTs. For the exogenous cue, we observed a spatial inhibition-of-return along with an object-based effect, implying that object-based attention is independent of space-based attention. Overall, our results reveal an oculomotor correlate of object-based attention, suggesting that, in addition to spatial priority, object-level priority also affects saccade planning. PMID:27225468

Low latency messages on distributed memory multiprocessors

NASA Technical Reports Server (NTRS)

Rosing, Matthew; Saltz, Joel

1993-01-01

Many of the issues in developing an efficient interface for communication on distributed memory machines are described and a portable interface is proposed. Although the hardware component of message latency is less than one microsecond on many distributed memory machines, the software latency associated with sending and receiving typed messages is on the order of 50 microseconds. The reason for this imbalance is that the software interface does not match the hardware. By changing the interface to match the hardware more closely, applications with fine grained communication can be put on these machines. Based on several tests that were run on the iPSC/860, an interface that will better match current distributed memory machines is proposed. The model used in the proposed interface consists of a computation processor and a communication processor on each node. Communication between these processors and other nodes in the system is done through a buffered network. Information that is transmitted is either data or procedures to be executed on the remote processor. The dual processor system is better suited for efficiently handling asynchronous communications compared to a single processor system. The ability to send data or procedure is very flexible for minimizing message latency, based on the type of communication being performed. The test performed and the proposed interface are described.

Latency of TCP applications over the ATM-WAN using the GFR service category

NASA Astrophysics Data System (ADS)

Chen, Kuo-Hsien; Siliquini, John F.; Budrikis, Zigmantas

1998-10-01

The GFR service category has been proposed for data services in ATM networks. Since users are ultimately interested in data service that provide high efficiency and low latency, it is important to study the latency performance for data traffic of the GFR service category in an ATM network. Today much of the data traffic utilizes the TCP/IP protocol suite and in this paper we study through simulation the latency of TCP applications running over a wide-area ATM network utilizing the GFR service category using a realistic TCP traffic model. From this study, we find that during congestion periods the reserved bandwidth in GFR can improve the latency performance for TCP applications. However, due to TCP 'Slow Start' data segment generation dynamics, we show that a large proportion of TCP segments are discarded under network congestion even when the reserved bandwidth is equal to the average generated rate of user data. Therefore, a user experiences worse than expected latency performance when the network is congested. In this study we also examine the effects of segment size on the latency performance of TCP applications using the GFR service category.

Latency Requirements for Head-Worn Display S/EVS Applications

NASA Technical Reports Server (NTRS)

Bailey, Randall E.; Trey Arthur, J. J., III; Williams, Steven P.

2004-01-01

NASA s Aviation Safety Program, Synthetic Vision Systems Project is conducting research in advanced flight deck concepts, such as Synthetic/Enhanced Vision Systems (S/EVS), for commercial and business aircraft. An emerging thrust in this activity is the development of spatially-integrated, large field-of-regard information display systems. Head-worn or helmet-mounted display systems are being proposed as one method in which to meet this objective. System delays or latencies inherent to spatially-integrated, head-worn displays critically influence the display utility, usability, and acceptability. Research results from three different, yet similar technical areas flight control, flight simulation, and virtual reality are collectively assembled in this paper to create a global perspective of delay or latency effects in head-worn or helmet-mounted display systems. Consistent definitions and measurement techniques are proposed herein for universal application and latency requirements for Head-Worn Display S/EVS applications are drafted. Future research areas are defined.

Latency requirements for head-worn display S/EVS applications

NASA Astrophysics Data System (ADS)

Bailey, Randall E.; Arthur, Jarvis J., III; Williams, Steven P.

2004-08-01

NASA's Aviation Safety Program, Synthetic Vision Systems Project is conducting research in advanced flight deck concepts, such as Synthetic/Enhanced Vision Systems (S/EVS), for commercial and business aircraft. An emerging thrust in this activity is the development of spatially-integrated, large field-of-regard information display systems. Head-worn or helmet-mounted display systems are being proposed as one method in which to meet this objective. System delays or latencies inherent to spatially-integrated, head-worn displays critically influence the display utility, usability, and acceptability. Research results from three different, yet similar technical areas - flight control, flight simulation, and virtual reality - are collectively assembled in this paper to create a global perspective of delay or latency effects in head-worn or helmet-mounted display systems. Consistent definitions and measurement techniques are proposed herein for universal application and latency requirements for Head-Worn Display S/EVS applications are drafted. Future research areas are defined.

Energy latency tradeoffs for medium access and sleep scheduling in wireless sensor networks

NASA Astrophysics Data System (ADS)

Gang, Lu

Wireless sensor networks are expected to be used in a wide range of applications from environment monitoring to event detection. The key challenge is to provide energy efficient communication; however, latency remains an important concern for many applications that require fast response. The central thesis of this work is that energy efficient medium access and sleep scheduling mechanisms can be designed without necessarily sacrificing application-specific latency performance. We validate this thesis through results from four case studies that cover various aspects of medium access and sleep scheduling design in wireless sensor networks. Our first effort, DMAC, is to design an adaptive low latency and energy efficient MAC for data gathering to reduce the sleep latency. We propose staggered schedule, duty cycle adaptation, data prediction and the use of more-to-send packets to enable seamless packet forwarding under varying traffic load and channel contentions. Simulation and experimental results show significant energy savings and latency reduction while ensuring high data reliability. The second research effort, DESS, investigates the problem of designing sleep schedules in arbitrary network communication topologies to minimize the worst case end-to-end latency (referred to as delay diameter). We develop a novel graph-theoretical formulation, derive and analyze optimal solutions for the tree and ring topologies and heuristics for arbitrary topologies. The third study addresses the problem of minimum latency joint scheduling and routing (MLSR). By constructing a novel delay graph, the optimal joint scheduling and routing can be solved by M node-disjoint paths algorithm under multiple channel model. We further extended the algorithm to handle dynamic traffic changes and topology changes. A heuristic solution is proposed for MLSR under single channel interference. In the fourth study, EEJSPC, we first formulate a fundamental optimization problem that provides tunable

Using Arduino microcontroller boards to measure response latencies.

PubMed

Schubert, Thomas W; D'Ausilio, Alessandro; Canto, Rosario

2013-12-01

Latencies of buttonpresses are a staple of cognitive science paradigms. Often keyboards are employed to collect buttonpresses, but their imprecision and variability decreases test power and increases the risk of false positives. Response boxes and data acquisition cards are precise, but expensive and inflexible, alternatives. We propose using open-source Arduino microcontroller boards as an inexpensive and flexible alternative. These boards connect to standard experimental software using a USB connection and a virtual serial port, or by emulating a keyboard. In our solution, an Arduino measures response latencies after being signaled the start of a trial, and communicates the latency and response back to the PC over a USB connection. We demonstrated the reliability, robustness, and precision of this communication in six studies. Test measures confirmed that the error added to the measurement had an SD of less than 1 ms. Alternatively, emulation of a keyboard results in similarly precise measurement. The Arduino performs as well as a serial response box, and better than a keyboard. In addition, our setup allows for the flexible integration of other sensors, and even actuators, to extend the cognitive science toolbox.

Saccade latency reveals episodic representation of object color.

PubMed

Gordon, Robert D

2014-08-01

While previous studies suggest that identity, but not color, plays a role in episodic object representation, such studies have typically used tasks in which only identity is relevant, raising the possibility that the results reflect task demands, rather than the general principles that underlie object representation. In the present study, participants viewed a preview display containing one (Experiments 1 and 2) or two (Experiment 3) letters, then viewed a target display containing a single letter, in either the same or a different location. Participants executed an immediate saccade to fixate the target; saccade latency served as the dependent variable. In all experiments, saccade latencies were longer to fixate a target appearing in its previewed location, consistent with a bias to attend to new objects rather than to objects for which episodic representations are being maintained in visual working memory. The results of Experiment 3 further demonstrate, however, that changing target color eliminates these latency differences. The results suggest that color and identity are part of episodic representation even when not task relevant and that examining biases in saccade execution may be a useful approach to studying episodic representation.

Latency of pupillary reflex to light stimulation and its relationship to aging.

DOT National Transportation Integrated Search

1965-09-01

A method is described for measuring pupillary contraction latency period regardless of initial absolute pupil diameter. Pupillary contraction latency period increases with age: the data presented show that the normal pupil, as usually found in health...

Role of Active Listening and Listening Effort on Contralateral Suppression of Transient Evoked Otoacousic Emissions

PubMed Central

Theruvan, Nikhitha B; Kumar, Kaushlendra; Bhat, Jayashree S

2017-01-01

Background and Objectives The present study aimed to investigate the effect of active listening and listening effort on the contralateral suppression of transient evoked otoacoustic emissions (CSTEOAEs). Subjects and Methods Twenty eight young adults participated in the study. Transient evoked otoacoustic emissions (TEOAEs) were recorded using ‘linear’ clicks at 60 dB peSPL, in three contralateral noise conditions. In condition 1, TEOAEs were obtained in the presence of white noise in the contralateral ear. While, in condition 2, speech was embedded into white noise at +3, −3, and −9 dB signal-to-noise ratio (SNR) and delivered to the contralateral ear. The SNR was varied to investigate the effect of listening effort on the CSTEOAE. In condition 3, speech was played backwards and embedded into white noise at −3 dB SNR. The conditions 1 and 3 served as passive listening condition and the condition 2 served as active listening condition. In active listening condition, the participants categorized the words in to two groups (e.g., animal and vehicle). Results CSTEOAE was found to be largest in the presence of white noise, and the amount of CSTEOAE was not significantly different between active and passive listening conditions (condition 2 and 3). Listening effort had an effect on the CSTEOAE, the amount of suppression increased with listening effort, when SNR was decreased from +3 dB to −3 dB. However, when the SNR was further reduced to −9 dB, there was no further increase in the amount of CSTEOAE, instead there was a reduction in the amount of suppression. Conclusions The findings of the present study show that listening effort might affect CSTEOAE. PMID:28417101

Gum chewing improves swallow frequency and latency in Parkinson patients: a preliminary study.

PubMed

South, Angela R; Somers, Stephanie M; Jog, Mandar S

2010-04-13

Reduced swallowing frequency affects secretion management in Parkinson disease (PD). Gum chewing increases saliva flow and swallow frequency. This study uses chewing gum to modify swallow frequency and latency between swallows in patients with PD. 1) Assess the frequency and latency of swallow at baseline (BL), during gum chewing (GC), and post gum chewing (PGC) for participants with PD (stage 2-4) nonsymptomatic for prandial dysphagia; and 2) assess carryover after gum is expectorated. Twenty participants were studied across 3 tasks, each of 5 minutes in duration: BL, GC, and PGC. Respiratory and laryngeal signals were continuously recorded using PowerLab (version 5.5.5; ADI Instruments, Castle Hill, Australia). Frequency and latency of swallow events were calculated. Differences (analysis of variance) are reported for frequency (p < 0.000001) and latency (p < 0.000001). Swallow frequency (mean +/- SD) increased during GC (14.95 +/- 3.02) compared with BL (3.1 +/- 2.85) and PGC (7.0 +/- 2.57). Latency in seconds (mean +/- SD) decreased during GC (24.1 +/- 4.174) and increased with BL (131.8 +/- 59.52) and PGC (mean = 60.74 +/- 25.25). Intertask comparisons (t test) found differences in swallow frequency and latency between tasks: BL vs GC (p < 0.0001, p < 0.0001), BL vs PGC (p < 0.0011, p < 0.0009), and GC vs PGC (p < 0.0001, p < 0.0002), respectively. Post hoc analysis showed carryover to 5.317 minutes. Modifying sensorimotor input by chewing gum alters frequency and latency of swallowing and may be an effective strategy for secretion management in Parkinson disease. This study provides Class III evidence that chewing gum increases swallow frequency and decreases latency of swallowing in an experiment in patients with stage 2 to 4 Parkinson disease who are nonsymptomatic for significant prandial dysphagia.

Saccade latency indexes exogenous and endogenous object-based attention.

PubMed

Şentürk, Gözde; Greenberg, Adam S; Liu, Taosheng

2016-10-01

Classic studies of object-based attention have utilized keypress responses as the main dependent measure. However, people typically make saccades to fixate important objects. Recent work has shown that attention may act differently when it is deployed covertly versus in advance of a saccade. We further investigated the link between saccades and attention by examining whether object-based effects can be observed for saccades. We adapted the classical double-rectangle cueing paradigm of Egly, Driver, and Rafal (1994), and measured both the first saccade latency and the keypress reaction time (RT) to a target that appeared at the end of one of the two rectangles. Our results showed that saccade latencies exhibited higher sensitivity than did RTs for detecting effects of attention. We also assessed the generality of the attention effects by testing three types of cues: hybrid (predictive and peripheral), exogenous (nonpredictive and peripheral), and endogenous (predictive and central). We found that both RTs and saccade latencies exhibited effects of both space-based and object-based attentional selection. However, saccade latencies showed a more robust attentional modulation than RTs. For the exogenous cues, we observed a spatial inhibition of return along with an object-based effect, implying that object-based attention is independent of space-based attention. Overall, our results revealed an oculomotor correlate of object-based attention, suggesting that, in addition to spatial priority, object-level priority also affects saccade planning.

Interval dosing with the HDAC inhibitor vorinostat effectively reverses HIV latency

PubMed Central

Archin, Nancie M.; Kirchherr, Jennifer L.; Sung, Julia A.M.; Clutton, Genevieve; Sholtis, Katherine; Xu, Yinyan; Allard, Brigitte; Stuelke, Erin; Kashuba, Angela D.; Kuruc, Joann D.; Gay, Cynthia L.; Goonetilleke, Nilu

2017-01-01

BACKGROUND. The histone deacetylase (HDAC) inhibitor vorinostat (VOR) can increase HIV RNA expression in vivo within resting CD4+ T cells of aviremic HIV+ individuals. However, while studies of VOR or other HDAC inhibitors have reported reversal of latency, none has demonstrated clearance of latent infection. We sought to identify the optimal dosing of VOR for effective serial reversal of HIV latency. METHODS. In a study of 16 HIV-infected, aviremic individuals, we measured resting CD4+ T cell–associated HIV RNA ex vivo and in vivo following a single exposure to VOR, and then in vivo after a pair of doses separated by 48 or 72 hours, and finally following a series of 10 doses given at 72-hour intervals. RESULTS. Serial VOR exposures separated by 72 hours most often resulted in an increase in cell-associated HIV RNA within circulating resting CD4+ T cells. VOR was well tolerated by all participants. However, despite serial reversal of latency over 1 month of VOR dosing, we did not observe a measurable decrease (>0.3 log10) in the frequency of latent infection within resting CD4+ T cells. CONCLUSIONS. These findings outline parameters for the experimental use of VOR to clear latent infection. Latency reversal can be achieved by VOR safely and repeatedly, but effective depletion of persistent HIV infection will require additional advances. In addition to improvements in latency reversal, these advances may include the sustained induction of potent antiviral immune responses capable of recognizing and clearing the rare cells in which HIV latency has been reversed. TRIAL REGISTRATION. Clinicaltrials.gov NCT01319383. FUNDING. NIH grants U01 AI095052, AI50410, and P30 CA016086 and National Center for Advancing Translational Sciences grant KL2 TR001109. PMID:28714868

Time Counts! Some Comments on System Latency in Head-Referenced Displays

NASA Technical Reports Server (NTRS)

Ellis, Stephen R.; Adelstein, Bernard D.

2013-01-01

System response latency is a prominent characteristic of human-computer interaction. Laggy systems are; however, not simply annoying but substantially reduce user productivity. The impact of latency on head referenced display systems, particularly head-mounted systems, is especially disturbing since not only can it interfere with dynamic registration in augmented reality displays but it also can in some cases indirectly contribute to motion sickness. We will summarize several experiments using standard psychophysical discrimination techniques that suggest what system latencies will be required to achieve perceptual stability for spatially referenced computer-generated imagery. In conclusion I will speculate about other system performance characteristics that I would hope to have for a dream augmented reality system.

Low-Latency Embedded Vision Processor (LLEVS)

DTIC Science & Technology

2016-03-01

26 3.2.3 Task 3 Projected Performance Analysis of FPGA- based Vision Processor ........... 31 3.2.3.1 Algorithms Latency Analysis ...Programmable Gate Array Custom Hardware for Real- Time Multiresolution Analysis . ............................................... 35...conduct data analysis for performance projections. The data acquired through measurements , simulation and estimation provide the requisite platform for

Investigation of koi herpesvirus latency in koi.

PubMed

Eide, Kathleen E; Miller-Morgan, Tim; Heidel, Jerry R; Kent, Michael L; Bildfell, Rob J; Lapatra, Scott; Watson, Gregory; Jin, Ling

2011-05-01

Koi herpesvirus (KHV) has recently been classified as a member of the family of Alloherpesviridae within the order of Herpesvirales. One of the unique features of Herpesviridae is latent infection following a primary infection. However, KHV latency has not been recognized. To determine if latency occurs in clinically normal fish from facilities with a history of KHV infection or exposure, the presence of the KHV genome was investigated in healthy koi by PCR and Southern blotting. KHV DNA, but not infectious virus or mRNAs from lytic infection, was detected in white blood cells from investigated koi. Virus shedding was examined via tissue culture and reverse transcription-PCR (RT-PCR) testing of gill mucus and feces from six koi every other day for 1 month. No infectious virus or KHV DNA was detected in fecal secretion or gill swabs, suggesting that neither acute nor persistent infection was present. To determine if KHV latent infections can be reactivated, six koi were subjected to a temperature stress regime. KHV DNA and infectious virus were detected in both gill and fecal swabs by day 8 following temperature stress. KHV DNA was also detectable in brain, spleen, gills, heart, eye, intestine, kidney, liver, and pancreas in euthanized koi 1 month post-temperature stress. Our study suggests that KHV may become latent in leukocytes and other tissues, that it can be reactivated from latency by temperature stress, and that it may be more widespread in the koi population than previously suspected.

Group II muscle afferents probably contribute to the medium latency soleus stretch reflex during walking in humans

PubMed Central

Grey, Michael J; Ladouceur, Michel; Andersen, Jacob B; Nielsen, Jens Bo; Sinkjær, Thomas

2001-01-01

The objective of this study was to determine which afferents contribute to the medium latency response of the soleus stretch reflex resulting from an unexpected perturbation during human walking. Fourteen healthy subjects walked on a treadmill at approximately 3.5 km h−1 with the left ankle attached to a portable stretching device. The soleus stretch reflex was elicited by applying small amplitude (∼8 deg) dorsiflexion perturbations 200 ms after heel contact. Short and medium latency responses were observed with latencies of 55 ± 5 and 78 ± 6 ms, respectively. The short latency response was velocity sensitive (P < 0.001), while the medium latency response was not (P = 0.725). Nerve cooling increased the delay of the medium latency component to a greater extent than that of the short latency component (P < 0.005). Ischaemia strongly decreased the short latency component (P = 0.004), whereas the medium latency component was unchanged (P = 0.437). Two hours after the ingestion of tizanidine, an α2-adrenergic receptor agonist known to selectively depress the transmission in the group II afferent pathway, the medium latency reflex was strongly depressed (P = 0.007), whereas the short latency component was unchanged (P = 0.653). An ankle block with lidocaine hydrochloride was performed to suppress the cutaneous afferents of the foot and ankle. Neither the short (P = 0.453) nor medium (P = 0.310) latency reflexes were changed. Our results support the hypothesis that, during walking the medium latency component of the stretch reflex resulting from an unexpected perturbation is contributed to by group II muscle afferents. PMID:11483721

Molecular Basis of Latency in Pathogenic Human Viruses

NASA Astrophysics Data System (ADS)

Garcia-Blanco, Mariano A.; Cullen, Bryan R.

1991-11-01

Several human viruses are able to latently infect specific target cell populations in vivo. Analysis of the replication cycles of herpes simplex virus, Epstein-Barr virus, and human immunodeficiency virus suggests that the latent infections established by these human pathogens primarily result from a lack of host factors critical for the expression of viral early gene products. The subsequent activation of specific cellular transcription factors in response to extracellular stimuli can induce the expression of these viral regulatory proteins and lead to a burst of lytic viral replication. Latency in these eukaryotic viruses therefore contrasts with latency in bacteriophage, which is maintained primarily by the expression of virally encoded repressors of lytic replication.

Ocular herpes simplex virus: how are latency, reactivation, recurrent disease and therapy interrelated?

PubMed

Al-Dujaili, Lena J; Clerkin, Patrick P; Clement, Christian; McFerrin, Harris E; Bhattacharjee, Partha S; Varnell, Emily D; Kaufman, Herbert E; Hill, James M

2011-08-01

Most humans are infected with herpes simplex virus (HSV) type 1 in early childhood and remain latently infected throughout life. While most individuals have mild or no symptoms, some will develop destructive HSV keratitis. Ocular infection with HSV-1 and its associated sequelae account for the majority of corneal blindness in industrialized nations. Neuronal latency in the peripheral ganglia is established when transcription of the viral genome is repressed (silenced) except for the latency-associated transcripts and microRNAs. The functions of latency-associated transcripts have been investigated since 1987. Roles have been suggested relating to reactivation, establishment of latency, neuronal protection, antiapoptosis, apoptosis, virulence and asymptomatic shedding. Here, we review HSV-1 latent infections, reactivation, recurrent disease and antiviral therapies for the ocular HSV diseases.

The utility of a 5(th) nap in multiple sleep latency test.

PubMed

Muza, Rexford; Lykouras, Dimosthenis; Rees, Kate

2016-02-01

This is the first study that aimed to look specifically at the utility of the 5(th) nap in the multiple sleep latency test (MSLT), a test used to assist in the diagnosis of narcolepsy. Data was retrospectively collected from the Sleep Disorders Centre of a Tertiary Hospital on patients that had a 5(th) nap during their MSLT from the 08(th) November 2011 to 12(th) November 2014. Fifty-three patients had a 5(th) nap performed out of 378 MSLT studies. In 16% of cases a diagnosis of narcolepsy was given directly due to the inclusion of the 5(th) nap on the MSLT. Here a 5(th) nap allowed diagnostic criteria of mean sleep latency <8 minutes and >2 SOREMPS to be met. In 53% of cases the mean sleep latency increased due to 5(th) nap inclusion; the mean sleep latency of the first four naps was 5.6 vs. 6.7 after inclusion of the 5(th) nap. The 5(th) nap is not often performed within the MSLT studies. Our study shows that only a few patients may benefit from a 5(th) nap opportunity which also led to increase of the mean sleep latency at the expense of extra time, cost, labour and increased patient anxiety.

Short latency vestibular evoked potentials in the chicken embryo

NASA Technical Reports Server (NTRS)

Jones, S. M.; Jones, T. A.

1996-01-01

Electrophysiological responses to pulsed linear acceleration stimuli were recorded in chicken embryos incubated for 19 or 20 days (E19/E20). Responses occurred within the first 16 ms following the stimulus onset. The evoked potentials disappeared following bilateral labyrinthectomy, but persisted following cochlear destruction alone, thus demonstrating that the responses were vestibular. Approximately 8 to 10 response peaks could be identified. The first 4 positive and corresponding negative components (early peaks with latencies < 6.0 ms) were scored and latencies and amplitudes quantified. Vestibular response latencies were significantly longer (P < 0.01) and amplitudes significantly smaller (P < 0.001) than those observed in 2-week-old birds. Mean response threshold for anesthetized embryos was -15.9dBre 1.0 g/ms, which was significantly higher (P < 0.03) than those observed in 2-week-old birds (-23.0dBre 1.0 g/ms). Latency/intensity functions (that is, slopes) were not significantly different between embryos and 2-week-old animals, but amplitude/intensity functions for embryos were significantly shallower than those for 2-week-old birds (P < 0.001). We presume that these differences reflect the refinement of sensory function that occurs following 19 to 20 days of incubation. The recording of vestibular evoked potentials provides an objective, direct and noninvasive measure of peripheral vestibular function in the embryo and, as such, the method shows promise as an investigative tool. The results of the present study form the definitive basis for using vestibular evoked potentials in the detailed study of avian vestibular ontogeny and factors that may influence it.

Cerebellar damage diminishes long-latency responses to multijoint perturbations

PubMed Central

Trautman, Paxson; Rasquinha, Russell J.; Bhanpuri, Nasir H.; Scott, Stephen H.; Bastian, Amy J.

2013-01-01

Damage to the cerebellum can cause significant problems in the coordination of voluntary arm movements. One prominent idea is that incoordination stems from an inability to predictively account for the complex mechanical interactions between the arm's several joints. Motivated by growing evidence that corrective feedback control shares important capabilities and neural substrates with feedforward control, we asked whether cerebellar damage impacts feedback stabilization of the multijoint arm appropriate for the arm's intersegmental dynamics. Specifically, we tested whether cerebellar dysfunction impacts the ability of posterior deltoid to incorporate elbow motion in its long-latency response (R2 = 45–75 ms and R3 = 75–100 ms after perturbation) to an unexpected torque perturbation. Healthy and cerebellar-damaged subjects were exposed to a selected pattern of shoulder-elbow displacements to probe the response pattern from this shoulder extensor muscle. The healthy elderly subjects expressed a long-latency response linked to both shoulder and elbow motion, including an increase/decrease in shoulder extensor activity with elbow flexion/extension. Critically, cerebellar-damaged subjects displayed the normal pattern of activity in the R3 period indicating an intact ability to rapidly integrate multijoint motion appropriate to the arm's intersegmental dynamics. However, cerebellar-damaged subjects had a lower magnitude of activity that was specific to the long-latency period (both R2 and R3) and a slightly delayed onset of multijoint sensitivity. Taken together, our results suggest that the basic motor pattern of the long-latency response is housed outside the cerebellum and is scaled by processes within the cerebellum. PMID:23390311

Auditory middle latency response in children with learning difficulties.

PubMed

Frizzo, Ana Claudia Figueiredo; Issac, Myriam Lima; Pontes-Fernandes, Angela Cristina; Menezes, Pedro de Lemos; Funayama, Carolina Araújo Rodrigues

2012-07-01

 This is an objective laboratory assessment of the central auditory systems of children with learning disabilities.  To examine and determine the properties of the components of the Auditory Middle Latency Response in a sample of children with learning disabilities.  This was a prospective, cross-sectional cohort study with quantitative, descriptive, and exploratory outcomes. We included 50 children aged 8-13 years of both genders with and without learning disorders. Those with disorders of known organic, environmental, or genetic causes were excluded.  The Na, Pa, and Nb waves were identified in all subjects. The ranges of the latency component values were as follows: Na = 9.8-32.3 ms, Pa = 19.0-51.4 ms, Nb = 30.0-64.3 ms (learning disorders group) and Na = 13.2-29.6 ms, Pa = 21.8-42.8 ms, Nb = 28.4-65.8 ms (healthy group). The values of the Na-Pa amplitude ranged from 0.3 to 6.8 ìV (learning disorders group) or 0.2-3.6 ìV (learning disorders group). Upon analysis, the functional characteristics of the groups were distinct: the left hemisphere Nb latency was longer in the study group than in the control group. Peculiarities of the electrophysiological measures were observed in the children with learning disorders. This study has provided information on the Auditory Middle Latency Response and can serve as a reference for other clinical and experimental studies in children with these disorders.

Delayed auditory pathway maturation and prematurity.

PubMed

Koenighofer, Martin; Parzefall, Thomas; Ramsebner, Reinhard; Lucas, Trevor; Frei, Klemens

2015-06-01

Hearing loss is the most common sensory disorder in developed countries and leads to a severe reduction in quality of life. In this uncontrolled case series, we evaluated the auditory development in patients suffering from congenital nonsyndromic hearing impairment related to preterm birth. Six patients delivered preterm (25th-35th gestational weeks) suffering from mild to profound congenital nonsyndromic hearing impairment, descending from healthy, nonconsanguineous parents and were evaluated by otoacoustic emissions, tympanometry, brainstem-evoked response audiometry, and genetic testing. All patients were treated with hearing aids, and one patient required cochlear implantation. One preterm infant (32nd gestational week) initially presented with a 70 dB hearing loss, accompanied by negative otoacoustic emissions and normal tympanometric findings. The patient was treated with hearing aids and displayed a gradual improvement in bilateral hearing that completely normalized by 14 months of age accompanied by the development of otoacoustic emission responses. Conclusions We present here for the first time a fully documented preterm patient with delayed auditory pathway maturation and normalization of hearing within 14 months of birth. Although rare, postpartum development of the auditory system should, therefore, be considered in the initial stages for treating preterm hearing impaired patients.

Reducing audio stimulus presentation latencies across studies, laboratories, and hardware and operating system configurations.

PubMed

Babjack, Destiny L; Cernicky, Brandon; Sobotka, Andrew J; Basler, Lee; Struthers, Devon; Kisic, Richard; Barone, Kimberly; Zuccolotto, Anthony P

2015-09-01

Using differing computer platforms and audio output devices to deliver audio stimuli often introduces (1) substantial variability across labs and (2) variable time between the intended and actual sound delivery (the sound onset latency). Fast, accurate audio onset latencies are particularly important when audio stimuli need to be delivered precisely as part of studies that depend on accurate timing (e.g., electroencephalographic, event-related potential, or multimodal studies), or in multisite studies in which standardization and strict control over the computer platforms used is not feasible. This research describes the variability introduced by using differing configurations and introduces a novel approach to minimizing audio sound latency and variability. A stimulus presentation and latency assessment approach is presented using E-Prime and Chronos (a new multifunction, USB-based data presentation and collection device). The present approach reliably delivers audio stimuli with low latencies that vary by ≤1 ms, independent of hardware and Windows operating system (OS)/driver combinations. The Chronos audio subsystem adopts a buffering, aborting, querying, and remixing approach to the delivery of audio, to achieve a consistent 1-ms sound onset latency for single-sound delivery, and precise delivery of multiple sounds that achieves standard deviations of 1/10th of a millisecond without the use of advanced scripting. Chronos's sound onset latencies are small, reliable, and consistent across systems. Testing of standard audio delivery devices and configurations highlights the need for careful attention to consistency between labs, experiments, and multiple study sites in their hardware choices, OS selections, and adoption of audio delivery systems designed to sidestep the audio latency variability issue.

Measurement and reduction of system latency in see-through helmet mounted display (HMD) systems

NASA Astrophysics Data System (ADS)

Vincenzi, Dennis A.; Deaton, John E.; Blickenderfer, Elizabeth L.; Pray, Rick; Williams, Barry; Buker, Timothy J.

2010-04-01

Future military aviation platforms such as the proposed Joint Strike Fighter F-35 will integrate helmet mounted displays (HMDs) with the avionics and weapon systems to the degree that the HMDs will become the aircraft's primary display system. In turn, training of pilot flight skills using HMDs will be essential in future training systems. In order to train these skills using simulation based training, improvements must be made in the integration of HMDs with out-thewindow (OTW) simulations. Currently, problems such as latency contribute to the onset of simulator sickness and provide distractions during training with HMD simulator systems that degrade the training experience. Previous research has used Kalman predictive filters as a means of mitigating the system latency present in these systems. While this approach has yielded some success, more work is needed to develop innovative and improved strategies that reduce system latency as well as to include data collected from the user perspective as a measured variable during test and evaluation of latency reduction strategies. The purpose of this paper is twofold. First, the paper describes a new method to measure and assess system latency from the user perspective. Second, the paper describes use of the testbed to examine the efficacy of an innovative strategy that combines a customized Kalman filter with a neural network approach to mitigate system latency. Results indicate that the combined approach reduced system latency significantly when compared to baseline data and the traditional Kalman filter. Reduced latency errors should mitigate the onset of simulator sickness and ease simulator sickness symptomology. Implications for training systems will be discussed.

Understanding and Analyzing Latency of Near Real-time Satellite Data

NASA Astrophysics Data System (ADS)

Han, W.; Jochum, M.; Brust, J.

2016-12-01

Acquiring and disseminating time-sensitive satellite data in a timely manner is much concerned by researchers and decision makers of weather forecast, severe weather warning, disaster and emergency response, environmental monitoring, and so on. Understanding and analyzing the latency of near real-time satellite data is very useful and helpful to explore the whole data transmission flow, indentify the possible issues, and connect data providers and users better. The STAR (Center for Satellite Applications and Research of NOAA) Central Data Repository (SCDR) is a central repository to acquire, manipulate, and disseminate various types of near real-time satellite datasets to internal and external users. In this system, important timestamps, including observation beginning/end, processing, uploading, downloading, and ingestion, are retrieved and organized in the database, so the time length of each transmission phase can be figured out easily. Open source NoSQL database MongoDB is selected to manage the timestamp information because of features of dynamic schema, aggregation and data processing. A user-friendly user interface is developed to visualize and characterize the latency interactively. Taking the Himawari-8 HSD (Himawari Standard Data) file as an example, the data transmission phases, including creating HSD file from satellite observation, uploading the file to HimawariCloud, updating file link in the webpage, downloading and ingesting the file to SCDR, are worked out from the above mentioned timestamps. The latencies can be observed by time of period, day of week, or hour of day in chart or table format, and the anomaly latencies can be detected and reported through the user interface. Latency analysis provides data providers and users actionable insight on how to improve the data transmission of near real-time satellite data, and enhance its acquisition and management.

Low Latency MAC Protocol in Wireless Sensor Networks Using Timing Offset

NASA Astrophysics Data System (ADS)

Choi, Seung Sik

This paper proposes a low latency MAC protocol that can be used in sensor networks. To extend the lifetime of sensor nodes, the conventional solution is to synchronize active/sleep periods of all sensor nodes. However, due to these synchronized sensor nodes, packets in the intermediate nodes must wait until the next node wakes up before it can forward a packet. This induces a large delay in sensor nodes. To solve this latency problem, a clustered sensor network which uses two types of sensor nodes and layered architecture is considered. Clustered heads in each cluster are synchronized with different timing offsets to reduce the sleep delay. Using this concept, the latency problem can be solved and more efficient power usage can be obtained.

Industrial WSN Based on IR-UWB and a Low-Latency MAC Protocol

NASA Astrophysics Data System (ADS)

Reinhold, Rafael; Underberg, Lisa; Wulf, Armin; Kays, Ruediger

2016-07-01

Wireless sensor networks for industrial communication require high reliability and low latency. As current wireless sensor networks do not entirely meet these requirements, novel system approaches need to be developed. Since ultra wideband communication systems seem to be a promising approach, this paper evaluates the performance of the IEEE 802.15.4 impulse-radio ultra-wideband physical layer and the IEEE 802.15.4 Low Latency Deterministic Network (LLDN) MAC for industrial applications. Novel approaches and system adaptions are proposed to meet the application requirements. In this regard, a synchronization approach based on circular average magnitude difference functions (CAMDF) and on a clean template (CT) is presented for the correlation receiver. An adapted MAC protocol titled aggregated low latency (ALL) MAC is proposed to significantly reduce the resulting latency. Based on the system proposals, a hardware prototype has been developed, which proves the feasibility of the system and visualizes the real-time performance of the MAC protocol.

Ocular herpes simplex virus: how are latency, reactivation, recurrent disease and therapy interrelated?

PubMed Central

Al-Dujaili, Lena J; Clerkin, Patrick P; Clement, Christian; McFerrin, Harris E; Bhattacharjee, Partha S; Varnell, Emily D; Kaufman, Herbert E; Hill, James M

2012-01-01

Most humans are infected with herpes simplex virus (HSV) type 1 in early childhood and remain latently infected throughout life. While most individuals have mild or no symptoms, some will develop destructive HSV keratitis. Ocular infection with HSV-1 and its associated sequelae account for the majority of corneal blindness in industrialized nations. Neuronal latency in the peripheral ganglia is established when transcription of the viral genome is repressed (silenced) except for the latency-associated transcripts and microRNAs. The functions of latency-associated transcripts have been investigated since 1987. Roles have been suggested relating to reactivation, establishment of latency, neuronal protection, antiapoptosis, apoptosis, virulence and asymptomatic shedding. Here, we review HSV-1 latent infections, reactivation, recurrent disease and antiviral therapies for the ocular HSV diseases. PMID:21861620

Investigation of Koi Herpesvirus Latency in Koi▿

PubMed Central

Eide, Kathleen E.; Miller-Morgan, Tim; Heidel, Jerry R.; Kent, Michael L.; Bildfell, Rob J.; LaPatra, Scott; Watson, Gregory; Jin, Ling

2011-01-01

Koi herpesvirus (KHV) has recently been classified as a member of the family of Alloherpesviridae within the order of Herpesvirales. One of the unique features of Herpesviridae is latent infection following a primary infection. However, KHV latency has not been recognized. To determine if latency occurs in clinically normal fish from facilities with a history of KHV infection or exposure, the presence of the KHV genome was investigated in healthy koi by PCR and Southern blotting. KHV DNA, but not infectious virus or mRNAs from lytic infection, was detected in white blood cells from investigated koi. Virus shedding was examined via tissue culture and reverse transcription-PCR (RT-PCR) testing of gill mucus and feces from six koi every other day for 1 month. No infectious virus or KHV DNA was detected in fecal secretion or gill swabs, suggesting that neither acute nor persistent infection was present. To determine if KHV latent infections can be reactivated, six koi were subjected to a temperature stress regime. KHV DNA and infectious virus were detected in both gill and fecal swabs by day 8 following temperature stress. KHV DNA was also detectable in brain, spleen, gills, heart, eye, intestine, kidney, liver, and pancreas in euthanized koi 1 month post-temperature stress. Our study suggests that KHV may become latent in leukocytes and other tissues, that it can be reactivated from latency by temperature stress, and that it may be more widespread in the koi population than previously suspected. PMID:21389134

ScriptingRT: A Software Library for Collecting Response Latencies in Online Studies of Cognition

PubMed Central

Schubert, Thomas W.; Murteira, Carla; Collins, Elizabeth C.; Lopes, Diniz

2013-01-01

ScriptingRT is a new open source tool to collect response latencies in online studies of human cognition. ScriptingRT studies run as Flash applets in enabled browsers. ScriptingRT provides the building blocks of response latency studies, which are then combined with generic Apache Flex programming. Six studies evaluate the performance of ScriptingRT empirically. Studies 1–3 use specialized hardware to measure variance of response time measurement and stimulus presentation timing. Studies 4–6 implement a Stroop paradigm and run it both online and in the laboratory, comparing ScriptingRT to other response latency software. Altogether, the studies show that Flash programs developed in ScriptingRT show a small lag and an increased variance in response latencies. However, this did not significantly influence measured effects: The Stroop effect was reliably replicated in all studies, and the found effects did not depend on the software used. We conclude that ScriptingRT can be used to test response latency effects online. PMID:23805326

Auditory middle latency response in children with learning difficulties

PubMed Central

Frizzo, Ana Claudia Figueiredo; Issac, Myriam Lima; Pontes-Fernandes, Angela Cristina; Menezes, Pedro de Lemos; Funayama, Carolina Araújo Rodrigues

2012-01-01

Summary Introduction: This is an objective laboratory assessment of the central auditory systems of children with learning disabilities. Aim: To examine and determine the properties of the components of the Auditory Middle Latency Response in a sample of children with learning disabilities. Methods: This was a prospective, cross-sectional cohort study with quantitative, descriptive, and exploratory outcomes. We included 50 children aged 8–13 years of both genders with and without learning disorders. Those with disorders of known organic, environmental, or genetic causes were excluded. Results and Conclusions: The Na, Pa, and Nb waves were identified in all subjects. The ranges of the latency component values were as follows: Na = 9.8–32.3 ms, Pa = 19.0–51.4 ms, Nb = 30.0–64.3 ms (learning disorders group) and Na = 13.2–29.6 ms, Pa = 21.8–42.8 ms, Nb = 28.4–65.8 ms (healthy group). The values of the Na-Pa amplitude ranged from 0.3 to 6.8 ìV (learning disorders group) or 0.2–3.6 ìV (learning disorders group). Upon analysis, the functional characteristics of the groups were distinct: the left hemisphere Nb latency was longer in the study group than in the control group. Peculiarities of the electrophysiological measures were observed in the children with learning disorders. This study has provided information on the Auditory Middle Latency Response and can serve as a reference for other clinical and experimental studies in children with these disorders. PMID:25991954

[The significance of the interaural latency difference of VEMP].

PubMed

Wu, Ziming; Zhang, Suzhen; Ji, Fei; Zhou, Na; Guo, Weiwei; Yang, Weiyan; Han, Dongyi

2005-05-01

To investigate the significance of the interaural latency (IAL) difference of the latency of VEMP and to raise the sensitivity of the test. Vestibular evoked myogenic potentials (VEMP) were tested in 20 healthy subjects; 13 patients with acoustic neuromaor cerebellopontile angle occupying lesions and 1 patient with multiple sclerosis. IAL differences of the wave p13,n23 and p13-n23 (abbreviatd as /delta p13/, /delta n23/ and /delta p13-n23/, respectively) were analysed to determine the normal range and the upper limit of the norm data. Four illustrative cases with the abnormality of the IAL difference were given as examples. The upper limit of the IAL of /delta p13/ was 1.13 ms; that of the /delta n23/ was 1.38 ms and that of /delta p13-n23/ was 1.54 ms. The /p13-n23/ latency between the right and left side had no significant difference (P > 0.05). /delta p13/, /delta n23/ and /delta p13-n23/, especially /delta p13/ of VEMP can suggest abnormality in the neural pathway and it may be applicable in practice.

Reliability of the nerve conduction monitor in repeated measures of median and ulnar nerve latencies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washington, I A

According to the Bureau of Labor Statistics, carpal tunnel syndrome (CTS), one of the most rapidly growing work-related injuries, cost American businesses up to $10 billion dollars in medical costs each year (1992). Because conservative therapy can be implemented and CTS is more reversible in it early stages, early detection will not only save industry unnecessary health care costs, but also prevent employees from experiencing debilitating pain and unnecessary surgery. In response to the growing number of cases of CTS, many companies have introduced screening tools to detect early stages of carpal tunnel syndrome. Neurotron Medical (New Jersey) has designedmore » a portable nerve conduction monitor (Nervepace S-200) which measures motor and sensory nerve latencies. The slowing of these latencies is one diagnostic indicator of carpal tunnel syndrome. In this study, we determined the reliability of the Nervepace Monitor in measure ulnar and median nerve latencies during repeated testing. The testing was performed on 28 normal subjects between the ages of 20 and 35 who had no prior symptoms of CTS. They were tested at the same time each day for three consecutive days. Nerve latencies between different ethnic groups and genders were compared. Results show that there was no significant daily variation of the median motor and lunar sensory latencies or the median sensory latencies. No significant differences of latencies was observed among ethnic groups; however, a significant difference of latencies between male and female subjects was observed (p<0.05).« less

Trial latencies estimation of event-related potentials in EEG by means of genetic algorithms

NASA Astrophysics Data System (ADS)

Da Pelo, P.; De Tommaso, M.; Monaco, A.; Stramaglia, S.; Bellotti, R.; Tangaro, S.

2018-04-01

Objective. Event-related potentials (ERPs) are usually obtained by averaging thus neglecting the trial-to-trial latency variability in cognitive electroencephalography (EEG) responses. As a consequence the shape and the peak amplitude of the averaged ERP are smeared and reduced, respectively, when the single-trial latencies show a relevant variability. To date, the majority of the methodologies for single-trial latencies inference are iterative schemes providing suboptimal solutions, the most commonly used being the Woody’s algorithm. Approach. In this study, a global approach is developed by introducing a fitness function whose global maximum corresponds to the set of latencies which renders the trial signals most aligned as possible. A suitable genetic algorithm has been implemented to solve the optimization problem, characterized by new genetic operators tailored to the present problem. Main results. The results, on simulated trials, showed that the proposed algorithm performs better than Woody’s algorithm in all conditions, at the cost of an increased computational complexity (justified by the improved quality of the solution). Application of the proposed approach on real data trials, resulted in an increased correlation between latencies and reaction times w.r.t. the output from RIDE method. Significance. The above mentioned results on simulated and real data indicate that the proposed method, providing a better estimate of single-trial latencies, will open the way to more accurate study of neural responses as well as to the issue of relating the variability of latencies to the proper cognitive and behavioural correlates.

EOS Data Products Latency and Reprocessing Evaluation

NASA Astrophysics Data System (ADS)

Ramapriyan, H. K.; Wanchoo, L.

2012-12-01

NASA's Earth Observing System (EOS) Data and Information System (EOSDIS) program has been processing, archiving, and distributing EOS data since the launch of Terra platform in 1999. The EOSDIS Distributed Active Archive Centers (DAACs) and Science-Investigator-led Processing Systems (SIPSs) are generating over 5000 unique products with a daily average volume of 1.7 Petabytes. Initially EOSDIS had requirements to make process data products within 24 hours of receiving all inputs needed for generating them. Thus, generally, the latency would be slightly over 24 and 48 hours after satellite data acquisition, respectively, for Level 1 and Level 2 products. Due to budgetary constraints these requirements were relaxed, with the requirement being to avoid a growing backlog of unprocessed data. However, the data providers have been generating these products in as timely a manner as possible. The reduction in costs of computing hardware has helped considerably. It is of interest to analyze the actual latencies achieved over the past several years in processing and inserting the data products into the EOSDIS archives for the users to support various scientific studies such as land processes, oceanography, hydrology, atmospheric science, cryospheric science, etc. The instrument science teams have continuously evaluated the data products since the launches of EOS satellites and improved the science algorithms to provide high quality products. Data providers have periodically reprocessed the previously acquired data with these improved algorithms. The reprocessing campaigns run for an extended time period in parallel with forward processing, since all data starting from the beginning of the mission need to be reprocessed. Each reprocessing activity involves more data than the previous reprocessing. The historical record of the reprocessing times would be of interest to future missions, especially those involving large volumes of data and/or computational loads due to

Factors influencing the response latencies of subnormal children in naming pictures.

PubMed

Elliott, C

1978-08-01

The times taken to name 56 drawings of objects on five separate occasions were analysed for 21 ESN(M) and 21 ESN(S) children, matched for picture-naming vocabulary. The ESN(S) group not only had a higher mean response latency but also showed greater inter- and intra-subject variance. Nine objects were selected whose names have a Thorndike-Lorge language frequency of 50 words per million or greater, and nine others were selected with a frequency of less than 50 words per million. Each object was drawn in two ways, one giving a two-dimensional outline with the addition of important detail, the other drawing also incorporating cues indicating the depth of the object. An analysis of variance of the children's latencies in naming the selected 36 pictures of 18 objects over five trials indicated that the method of drawing had no effect upon naming latencies. Pictures with high-frequency names were named faster than those with lower frequency names, the ESN(S) group showing a greater rate of increase in naming latency for the lower frequency words than the ESN(M) children. Results were discussed in terms of the Oldfield and Lachman models of lexical memory storage and of the search processes required for the retrieval of names.

Attention Influences Single Unit and Local Field Potential Response Latencies in Visual Cortical Area V4

PubMed Central

Sundberg, Kristy A.; Mitchell, Jude F.; Gawne, Timothy J.

2012-01-01

Many previous studies have demonstrated that changes in selective attention can alter the response magnitude of visual cortical neurons, but there has been little evidence for attention affecting response latency. Small latency differences, though hard to detect, can potentially be of functional importance, and may also give insight into the mechanisms of neuronal computation. We therefore reexamined the effect of attention on the response latency of both single units and the local field potential (LFP) in primate visual cortical area V4. We find that attention does produce small (1–2 ms) but significant reductions in the latency of both the spiking and LFP responses. Though attention, like contrast elevation, reduces response latencies, we find that the two have different effects on the magnitude of the LFP. Contrast elevations increase and attention decreases the magnitude of the initial deflection of the stimulus-evoked LFP. Both contrast elevation and attention increase the magnitude of the spiking response. We speculate that latencies may be reduced at higher contrast because stronger stimulus inputs drive neurons more rapidly to spiking threshold, while attention may reduce latencies by placing neurons in a more depolarized state closer to threshold before stimulus onset. PMID:23136440

Low Latency Audio Video: Potentials for Collaborative Music Making through Distance Learning

ERIC Educational Resources Information Center

Riley, Holly; MacLeod, Rebecca B.; Libera, Matthew

2016-01-01

The primary purpose of this study was to examine the potential of LOw LAtency (LOLA), a low latency audio visual technology designed to allow simultaneous music performance, as a distance learning tool for musical styles in which synchronous playing is an integral aspect of the learning process (e.g., jazz, folk styles). The secondary purpose was…

Effect of squatting velocity on hip muscle latency in women with patellofemoral pain syndrome.

PubMed

Orozco-Chavez, Ignacio; Mendez-Rebolledo, Guillermo

2018-03-01

[Purpose] Neuromuscular activity has been evaluated in patellofemoral pain syndrome but movement velocity has not been considered. The aim was to determine differences in onset latency of hip and knee muscles between individuals with and without patellofemoral pain syndrome during a single leg squat, and whether any differences are dependent on movement velocity. [Subjects and Methods] Twenty-four females with patellofemoral pain syndrome and 24 healthy females participated. Onset latency of gluteus maximus, anterior and posterior gluteus medius, rectus femoris, vastus medialis, vastus lateralis and biceps femoris during a single leg squat at high and low velocity were evaluated. [Results] There was an interaction between velocity and diagnosis for posterior gluteus medius. Healthy subjects showed a later posterior gluteus medius onset latency at low velocity than high velocity; and also later than patellofemoral pain syndrome subjects at low velocity and high velocity. [Conclusion] Patellofemoral pain syndrome subjects presented an altered latency of posterior gluteus medius during a single leg squat and did not generate adaptations to velocity variation, while healthy subjects presented an earlier onset latency in response to velocity increase.

Functional modeling of the human auditory brainstem response to broadband stimulationa)

PubMed Central

Verhulst, Sarah; Bharadwaj, Hari M.; Mehraei, Golbarg; Shera, Christopher A.; Shinn-Cunningham, Barbara G.

2015-01-01

Population responses such as the auditory brainstem response (ABR) are commonly used for hearing screening, but the relationship between single-unit physiology and scalp-recorded population responses are not well understood. Computational models that integrate physiologically realistic models of single-unit auditory-nerve (AN), cochlear nucleus (CN) and inferior colliculus (IC) cells with models of broadband peripheral excitation can be used to simulate ABRs and thereby link detailed knowledge of animal physiology to human applications. Existing functional ABR models fail to capture the empirically observed 1.2–2 ms ABR wave-V latency-vs-intensity decrease that is thought to arise from level-dependent changes in cochlear excitation and firing synchrony across different tonotopic sections. This paper proposes an approach where level-dependent cochlear excitation patterns, which reflect human cochlear filter tuning parameters, drive AN fibers to yield realistic level-dependent properties of the ABR wave-V. The number of free model parameters is minimal, producing a model in which various sources of hearing-impairment can easily be simulated on an individualized and frequency-dependent basis. The model fits latency-vs-intensity functions observed in human ABRs and otoacoustic emissions while maintaining rate-level and threshold characteristics of single-unit AN fibers. The simulations help to reveal which tonotopic regions dominate ABR waveform peaks at different stimulus intensities. PMID:26428802

Intraoperative observation of changes in cochlear nerve action potentials during exposure to electromagnetic fields generated by mobile phones.

PubMed

Colletti, Vittorio; Mandalà, Marco; Manganotti, Paolo; Ramat, Stefano; Sacchetto, Luca; Colletti, Liliana

2011-07-01

The rapid spread of devices generating electromagnetic fields (EMF) has raised concerns as to the possible effects of this technology on humans. The auditory system is the neural organ most frequently and directly exposed to electromagnetic activity owing to the daily use of mobile phones. In recent publications, a possible correlation between mobile phone usage and central nervous system tumours has been detected. Very recently a deterioration in otoacoustic emissions and in the auditory middle latency responses after intensive and long-term magnetic field exposure in humans has been demonstrated. To determine with objective observations if exposure to mobile phone EMF affects acoustically evoked cochlear nerve compound action potentials, seven patients suffering from Ménière's disease and undergoing retrosigmoid vestibular neurectomy were exposed to the effects of mobile phone placed over the craniotomy for 5 min. All patients showed a substantial decrease in amplitude and a significant increase in latency of cochlear nerve compound action potentials during the 5 min of exposure to EMF. These changes lasted for a period of around 5 min after exposure. The possibility that EMF can produce relatively long-lasting effects on cochlear nerve conduction is discussed and analysed in light of contrasting previous literature obtained under non-surgical conditions. Limitations of this novel approach, including the effects of the anaesthetics, craniotomy and surgical procedure, are presented in detail.

HTLV-1 Tax activates HIV-1 transcription in latency models.

PubMed

Geddes, Victor Emmanuel Viana; José, Diego Pandeló; Leal, Fabio E; Nixon, Douglas F; Tanuri, Amilcar; Aguiar, Renato Santana

2017-04-01

HIV-1 latency is a major obstacle to HIV-1 eradication. Coinfection with HTLV-1 has been associated with faster progression to AIDS. HTLV-1 encodes the transactivator Tax which can activate both HTLV-1 and HIV-1 transcription. Here, we demonstrate that Tax activates HIV transcription in latent CD4 + T cells. Tax promotes the activation of P-TEFb, releasing CDK9 and Cyclin T1 from inactive forms, promoting transcription elongation and reactivation of latent HIV-1. Tax mutants lacking interaction with the HIV-1-LTR promoter were not able to activate P-TEFb, with no subsequent activation of latent HIV. In HIV-infected primary resting CD4 + T cells, Tax-1 reactivated HIV-1 transcription up to five fold, confirming these findings in an ex vivo latency model. Finally, our results confirms that HTLV-1/Tax hijacks cellular partners, promoting HIV-1 transcription, and this interaction should be further investigated in HIV-1 latency studies in patients with HIV/HTLV-1 co-infection. Copyright © 2017 Elsevier Inc. All rights reserved.

Latency-Based and Psychophysiological Measures of Sexual Interest Show Convergent and Concurrent Validity.

PubMed

Ó Ciardha, Caoilte; Attard-Johnson, Janice; Bindemann, Markus

2018-04-01

Latency-based measures of sexual interest require additional evidence of validity, as do newer pupil dilation approaches. A total of 102 community men completed six latency-based measures of sexual interest. Pupillary responses were recorded during three of these tasks and in an additional task where no participant response was required. For adult stimuli, there was a high degree of intercorrelation between measures, suggesting that tasks may be measuring the same underlying construct (convergent validity). In addition to being correlated with one another, measures also predicted participants' self-reported sexual interest, demonstrating concurrent validity (i.e., the ability of a task to predict a more validated, simultaneously recorded, measure). Latency-based and pupillometric approaches also showed preliminary evidence of concurrent validity in predicting both self-reported interest in child molestation and viewing pornographic material containing children. Taken together, the study findings build on the evidence base for the validity of latency-based and pupillometric measures of sexual interest.

Temporal parameters and time course of perceptual latency priming.

PubMed

Scharlau, Ingrid; Neumann, Odmar

2003-06-01

Visual stimuli (primes) reduce the perceptual latency of a target appearing at the same location (perceptual latency priming, PLP). Three experiments assessed the time course of PLP by masked and, in Experiment 3, unmasked primes. Experiments 1 and 2 investigated the temporal parameters that determine the size of priming. Stimulus onset asynchrony was found to exert the main influence accompanied by a small effect of prime duration. Experiment 3 used a large range of priming onset asynchronies. We suggest to explain PLP by the Asynchronous Updating Model which relates it to the asynchrony of 2 central coding processes, preattentive coding of basic visual features and attentional orienting as a prerequisite for perceptual judgments and conscious perception.

A Novel Mechanism of Latency in Matrix Metalloproteinases*

PubMed Central

López-Pelegrín, Mar; Ksiazek, Miroslaw; Karim, Abdulkarim Y.; Guevara, Tibisay; Arolas, Joan L.; Potempa, Jan; Gomis-Rüth, F. Xavier

2015-01-01

The matrix metalloproteinases (MMPs) are a family of secreted soluble or membrane-anchored multimodular peptidases regularly found in several paralogous copies in animals and plants, where they have multiple functions. The minimal consensus domain architecture comprises a signal peptide, a 60–90-residue globular prodomain with a conserved sequence motif including a cysteine engaged in “cysteine-switch” or “Velcro” mediated latency, and a catalytic domain. Karilysin, from the human periodontopathogen Tannerella forsythia, is the only bacterial MMP to have been characterized biochemically to date. It shares with eukaryotic forms the catalytic domain but none of the flanking domains. Instead of the consensus MMP prodomain, it features a 14-residue propeptide, the shortest reported for a metallopeptidase, which lacks cysteines. Here we determined the structure of a prokarilysin fragment encompassing the propeptide and the catalytic domain, and found that the former runs across the cleft in the opposite direction to a bound substrate and inhibits the latter through an “aspartate-switch” mechanism. This finding is reminiscent of latency maintenance in the otherwise unrelated astacin and fragilysin metallopeptidase families. In addition, in vivo and biochemical assays showed that the propeptide contributes to protein folding and stability. Our analysis of prokarilysin reveals a novel mechanism of latency and activation in MMPs. Finally, our findings support the view that the karilysin catalytic domain was co-opted by competent bacteria through horizontal gene transfer from a eukaryotic source, and later evolved in a specific bacterial environment. PMID:25555916

A new, ultra-low latency data transmission protocol for Earthquake Early Warning Systems

NASA Astrophysics Data System (ADS)

Hill, P.; Hicks, S. P.; McGowan, M.

2016-12-01

One measure used to assess the performance of Earthquake Early Warning Systems (EEWS) is the delay time between earthquake origin and issued alert. EEWS latency is dependent on a number of sources (e.g. P-wave propagation, digitisation, transmission, receiver processing, triggering, event declaration). Many regional seismic networks use the SEEDlink protocol; however, packet size is fixed to 512-byte miniSEED records, resulting in transmission latencies of >0.5 s. Data packetisation is seen as one of the main sources of delays in EEWS (Brown et al., 2011). Optimising data-logger and telemetry configurations is a cost-effective strategy to improve EEWS alert times (Behr et al., 2015). Digitisers with smaller, selectable packets can result in faster alerts (Sokos et al., 2016). We propose a new seismic protocol for regional seismic networks benefiting low-latency applications such as EEWS. The protocol, based on Güralp's existing GDI-link format is an efficient and flexible method to exchange data between seismic stations and data centers for a range of network configurations. The main principle is to stream data sample-by-sample instead of fixed-length packets to minimise transmission latency. Self-adaptive packetisation with compression maximises available telemetry bandwidth. Highly flexible metadata fields within GDI-link are compatible with existing miniSEED definitions. Data is sent as integers or floats, supporting a wide range of data formats, including discrete parameters such as Pd & τC for on-site earthquake early warning. Other advantages include: streaming station state-of-health information, instrument control, support of backfilling and fail-over strategies during telemetry outages. Based on tests carried out on the Güralp Minimus data-logger, we show our new protocol can reduce transmission latency to as low as 1 ms. The low-latency protocol is currently being implemented with common processing packages. The results of these tests will help to

Auditory Middle Latency Response and Phonological Awareness in Students with Learning Disabilities

PubMed Central

Romero, Ana Carla Leite; Funayama, Carolina Araújo Rodrigues; Capellini, Simone Aparecida; Frizzo, Ana Claudia Figueiredo

2015-01-01

Introduction Behavioral tests of auditory processing have been applied in schools and highlight the association between phonological awareness abilities and auditory processing, confirming that low performance on phonological awareness tests may be due to low performance on auditory processing tests. Objective To characterize the auditory middle latency response and the phonological awareness tests and to investigate correlations between responses in a group of children with learning disorders. Methods The study included 25 students with learning disabilities. Phonological awareness and auditory middle latency response were tested with electrodes placed on the left and right hemispheres. The correlation between the measurements was performed using the Spearman rank correlation coefficient. Results There is some correlation between the tests, especially between the Pa component and syllabic awareness, where moderate negative correlation is observed. Conclusion In this study, when phonological awareness subtests were performed, specifically phonemic awareness, the students showed a low score for the age group, although for the objective examination, prolonged Pa latency in the contralateral via was observed. Negative weak to moderate correlation for Pa wave latency was observed, as was positive weak correlation for Na-Pa amplitude. PMID:26491479

Trade-off between synergy and efficacy in combinations of HIV-1 latency-reversing agents.

PubMed

Gupta, Vipul; Dixit, Narendra M

2018-02-01

Eradicating HIV-1 infection is difficult because of the reservoir of latently infected cells that gets established soon after infection, remains hidden from antiretroviral drugs and host immune responses, and retains the capacity to reignite infection following the cessation of treatment. Drugs called latency-reversing agents (LRAs) are being developed to reactivate latently infected cells and render them susceptible to viral cytopathicity or immune killing. Whereas individual LRAs have failed to induce adequate reactivation, pairs of LRAs have been identified recently that act synergistically and hugely increase reactivation levels compared to individual LRAs. The maximum synergy achievable with LRA pairs is of clinical importance, as it would allow latency-reversal with minimal drug exposure. Here, we employed stochastic simulations of HIV-1 transcription and translation in latently infected cells to estimate this maximum synergy. We incorporated the predominant mechanisms of action of the two most promising classes of LRAs, namely, protein kinase C agonists and histone deacetylase inhibitors, and quantified the activity of individual LRAs in the two classes by mapping our simulations to corresponding in vitro experiments. Without any adjustable parameters, our simulations then quantitatively captured experimental observations of latency-reversal when the LRAs were used in pairs. Performing simulations representing a wide range of drug concentrations, we estimated the maximum synergy achievable with these LRA pairs. Importantly, we found with all the LRA pairs we considered that concentrations yielding the maximum synergy did not yield the maximum latency-reversal. Increasing concentrations to increase latency-reversal compromised synergy, unravelling a trade-off between synergy and efficacy in LRA combinations. The maximum synergy realizable with LRA pairs would thus be restricted by the desired level of latency-reversal, a constrained optimum we elucidated with

Exploring the Relationship between Physiological Measures of Cochlear and Brainstem Function

PubMed Central

Dhar, S.; Abel, R.; Hornickel, J.; Nicol, T.; Skoe, E.; Zhao, W.; Kraus, N.

2009-01-01

Objective Otoacoustic emissions and the speech-evoked auditory brainstem response are objective indices of peripheral auditory physiology and are used clinically for assessing hearing function. While each measure has been extensively explored, their interdependence and the relationships between them remain relatively unexplored. Methods Distortion product otoacoustic emissions (DPOAE) and speech-evoked auditory brainstem responses (sABR) were recorded from 28 normal-hearing adults. Through correlational analyses, DPOAE characteristics were compared to measures of sABR timing and frequency encoding. Data were organized into two DPOAE (Strength and Structure) and five brainstem (Onset, Spectrotemporal, Harmonics, Envelope Boundary, Pitch) composite measures. Results DPOAE Strength shows significant relationships with sABR Spectrotemporal and Harmonics measures. DPOAE Structure shows significant relationships with sABR Envelope Boundary. Neither DPOAE Strength nor Structure is related to sABR Pitch. Conclusions The results of the present study show that certain aspects of the speech-evoked auditory brainstem responses are related to, or covary with, cochlear function as measured by distortion product otoacoustic emissions. Significance These results form a foundation for future work in clinical populations. Analyzing cochlear and brainstem function in parallel in different clinical populations will provide a more sensitive clinical battery for identifying the locus of different disorders (e.g., language based learning impairments, hearing impairment). PMID:19346159

Effects of Differential Reinforcement of Short Latencies on Response Latency, Task Completion, and Accuracy of an Adolescent with Autism

ERIC Educational Resources Information Center

Donohue, Melanie M.; Casey, Laura Baylot; Bicard, David F.; Bicard, Sara E.

2012-01-01

Children with Autism Spectrum Disorder (ASD) are faced with many challenging behaviors that could impede their learning. One commonly reported problem behavior is noncompliance, which is often defined as a delay in response (latency), decrease in rate of responding (fluency), or failure to complete a task. This failure to comply in an appropriate…

Comparison of Polysomnography and Multiple Sleep Latency Test Findings in Subjects with Narcolepsy and İdiopathic Hypersomnia.

PubMed

Erdem, Murat; Bolu, Abdullah; Ünlü, A Gazi; Alper, Mustafa; Yetkin, Sinan

2013-09-01

Both narcolepsy and idiopathic hypersomnia are the main causes of excessive daytime sleepiness. In this study, we aimed to compare polysomnography (PSG) and multiple sleep latency test (MSLT) findings in narcolepsy and idiopathic hypersomnia patients. The files of patients with narcolepsy and hypersomnia who were admitted between 1995 and 2009 were reviewed. We evaluated data from 94 patients with narcolepsy with cataplexy, 49 with narcolepsy without cataplexy and 140 patients with idiopathic hypersomnia. Sleep latency and REM latency were longer in idiopathic hypersomnia group than in narcolepsy with and without cataplexy group. Mean sleep latency in MSLT was the shortest in narcolepsy with cataplexy group. There was no difference in sleep efficiency, percentage of sleep stage and number of awakenings in PSG between three groups. The findings of the study indicated that narcolepsy patients differ from idiopathic hypersomnia patients in terms of sleep latency and REM latency in PSG.

Aberrant intracellular localization of Varicella-Zoster virus regulatory proteins during latency

PubMed Central

Lungu, Octavian; Panagiotidis, Christos A.; Annunziato, Paula W.; Gershon, Anne A.; Silverstein, Saul J.

1998-01-01

Varicella-Zoster virus (VZV) is a herpesvirus that becomes latent in sensory neurons after primary infection (chickenpox) and subsequently may reactivate to cause zoster. The mechanism by which this virus maintains latency, and the factors involved, are poorly understood. Here we demonstrate, by immunohistochemical analysis of ganglia obtained at autopsy from seropositive patients without clinical symptoms of VZV infection that viral regulatory proteins are present in latently infected neurons. These proteins, which localize to the nucleus of cells during lytic infection, predominantly are detected in the cytoplasm of latently infected neurons. The restriction of regulatory proteins from the nucleus of latently infected neurons might interrupt the cascade of virus gene expression that leads to a productive infection. Our findings raise the possibility that VZV has developed a novel mechanism for maintenance of latency that contrasts with the transcriptional repression that is associated with latency of herpes simplex virus, the prototypic alpha herpesvirus. PMID:9618542

Response Latency Measures for Biographical Inventories

DTIC Science & Technology

1991-03-01

research (Trent et al., 1989). Procedures The ASAP, followed by one or more experimental cognitive tests, was computer administered to groups of...comprehension, and binary " true /false" decision about the item. This last stage, in turn, is divided into two substages: self-referent decision...apply stage) As a first step in partitioning latencies, it would be prudent to control experimentally for item length, as had been done in a few studies

Fast Reverse Propagation of Sound in the Living Cochlea

PubMed Central

He, Wenxuan; Fridberger, Anders; Porsov, Edward; Ren, Tianying

2010-01-01

Abstract The auditory sensory organ, the cochlea, not only detects but also generates sounds. Such sounds, otoacoustic emissions, are widely used for diagnosis of hearing disorders and to estimate cochlear nonlinearity. However, the fundamental question of how the otoacoustic emission exits the cochlea remains unanswered. In this study, emissions were provoked by two tones with a constant frequency ratio, and measured as vibrations at the basilar membrane and at the stapes, and as sound pressure in the ear canal. The propagation direction and delay of the emission were determined by measuring the phase difference between basilar membrane and stapes vibrations. These measurements show that cochlea-generated sound arrives at the stapes earlier than at the measured basilar membrane location. Data also show that basilar membrane vibration at the emission frequency is similar to that evoked by external tones. These results conflict with the backward-traveling-wave theory and suggest that at low and intermediate sound levels, the emission exits the cochlea predominantly through the cochlear fluids. PMID:20513393

Reduced evolutionary rates in HIV-1 reveal extensive latency periods among replicating lineages.

PubMed

Immonen, Taina T; Leitner, Thomas

2014-10-16

HIV-1 can persist for the duration of a patient's life due in part to its ability to hide from the immune system, and from antiretroviral drugs, in long-lived latent reservoirs. Latent forms of HIV-1 may also be disproportionally involved in transmission. Thus, it is important to detect and quantify latency in the HIV-1 life cycle. We developed a novel molecular clock-based phylogenetic tool to investigate the prevalence of HIV-1 lineages that have experienced latency. The method removes alternative sources that may affect evolutionary rates, such as hypermutation, recombination, and selection, to reveal the contribution of generation-time effects caused by latency. Our method was able to recover latent lineages with high specificity and sensitivity, and low false discovery rates, even on relatively short branches on simulated phylogenies. Applying the tool to HIV-1 sequences from 26 patients, we show that the majority of phylogenetic lineages have been affected by generation-time effects in every patient type, whether untreated, elite controller, or under effective or failing treatment. Furthermore, we discovered extensive effects of latency in sequence data (gag, pol, and env) from reservoirs as well as in the replicating plasma population. To better understand our phylogenetic findings, we developed a dynamic model of virus-host interactions to investigate the proportion of lineages in the actively replicating population that have ever been latent. Assuming neutral evolution, our dynamic modeling showed that under most parameter conditions, it is possible for a few activated latent viruses to propagate so that in time, most HIV-1 lineages will have been latent at some time in their past. These results suggest that cycling in and out of latency plays a major role in the evolution of HIV-1. Thus, no aspect of HIV-1 evolution can be fully understood without considering latency - including treatment, drug resistance, immune evasion, transmission, and pathogenesis.

REM sleep latency and neurocognitive dysfunction in schizophrenia

PubMed Central

Das, Mrinmay; Das, Ruchika; Khastgir, Udayan; Goswami, Utpal

2005-01-01

Background: Cognitive deficits—the hallmark of schizophrenic deterioration—still remain elusive as far as their pathophysiology is concerned. Various neurotransmitter systems have been implicated to explain these deficits. Abnormalities in cholinergic neurotransmission in the brain are one of the postulations; acetylcholine has also been postulated to regulate rapid eye movement (REM) sleep, especially REM latency. Thus, REM latency in patients with schizophrenia might provide a non-invasive window to look into the cholinergic functions of the brain. Aim: To study REM sleep measures and neurocognitive function in schizophrenia, and the changes occurring in these parameters following pharmacological treatment. Methods: Thirty subjects (15 with schizophrenia and 15 normal non-relative controls) were evaluated in this study. Most patients with schizophrenia had prominent negative symptoms and deficits in the performance in neurocognitive tests battery. They were treated with antipsychotics for a variable period of time and post-treatment evaluation was done using the same battery of neurocognitive tests and polysomnography. Patients were either drug-naïve or kept drug-free for at least two weeks both at baseline as well as at the post-treatment stage. Results: A positive correlation between the severity of negative symptoms and neurocognitive deficits (especially on the Wisconsin Card Sorting), and a negative correlation between these two parameters and REM latency was observed. Conclusion: It can be hypothesized that the acetylcholine deficit model of dementia cannot be applied to schizophrenic dementia, rather a hypercholinergic state results. This state warrants anticholinergic medication as a treatment option for negative symptoms of schizophrenia. PMID:20814454

A Gammaherpesviral Internal Repeat Contributes to Latency Amplification

PubMed Central

Thakur, Nagendra N.; El-Gogo, Susanne; Steer, Beatrix; Freimüller, Klaus; Waha, Andreas; Adler, Heiko

2007-01-01

Background Gammaherpesviruses cause important infections of humans, in particular in immunocompromised patients. The genomes of gammaherpesviruses contain variable numbers of internal repeats whose precise role for in vivo pathogenesis is not well understood. Methodology/Principal Findings We used infection of laboratory mice with murine gammaherpesvirus 68 (MHV-68) to explore the biological role of the 40 bp internal repeat of MHV-68. We constructed several mutant viruses partially or completely lacking this repeat. Both in vitro and in vivo, the loss of the repeat did not substantially affect lytic replication of the mutant viruses. However, the extent of splenomegaly, which is associated with the establishment of latency, and the number of ex vivo reactivating and genome positive splenocytes were reduced. Since the 40 bp repeat is part of the hypothetical open reading frame (ORF) M6, it might function as part of M6 or as an independent structure. To differentiate between these two possibilities, we constructed an N-terminal M6STOP mutant, leaving the repeat structure intact but rendering ORF M6 unfunctional. Disruption of ORF M6 did neither affect lytic nor latent infection. In contrast to the situation in lytically infected NIH3T3 cells, the expression of the latency-associated genes K3 and ORF72 was reduced in the latently infected murine B cell line Ag8 in the absence of the 40 bp repeat. Conclusions/Significance These data suggest that the 40 bp repeat contributes to latency amplification and might be involved in the regulation of viral gene expression. PMID:17710133

Measurement-based analysis of error latency. [in computer operating system

NASA Technical Reports Server (NTRS)

Chillarege, Ram; Iyer, Ravishankar K.

1987-01-01

This paper demonstrates a practical methodology for the study of error latency under a real workload. The method is illustrated with sampled data on the physical memory activity, gathered by hardware instrumentation on a VAX 11/780 during the normal workload cycle of the installation. These data are used to simulate fault occurrence and to reconstruct the error discovery process in the system. The technique provides a means to study the system under different workloads and for multiple days. An approach to determine the percentage of undiscovered errors is also developed and a verification of the entire methodology is performed. This study finds that the mean error latency, in the memory containing the operating system, varies by a factor of 10 to 1 (in hours) between the low and high workloads. It is found that of all errors occurring within a day, 70 percent are detected in the same day, 82 percent within the following day, and 91 percent within the third day. The increase in failure rate due to latency is not so much a function of remaining errors but is dependent on whether or not there is a latent error.

The behaviour of the long-latency stretch reflex in patients with Parkinson's disease

PubMed Central

Rothwell, Jc; Obeso, Ja; Traub, Mm; Marsden, Cd

1983-01-01

The size of the long-latency stretch reflex was measured in a proximal (triceps) and distal (flexor pollicis longus) muscle in 47 patients with Parkinson's disease, and was compared with that seen in a group of 12 age-matched normal control subjects. The patients were classified clinically into four groups according to the degree of rigidity at the elbow or tremor. Stretch reflexes were evaluated while the subject was exerting a small force against a constant preload supplied by a torque motor, and the size of the reflex response was measured as fractional increase over basal levels of activity. When stretches were given at random intervals by increasing the force exerted by the motor by a factor of 2 or 3, there was a clear trend for the more severely affected patients to have larger long latency responses in the triceps muscle, although there was no change in the size of the short-latency, spinal component of the response. In contrast, there was no change in the size of the long-latency response of the flexor pollicis longus in any group of patients with Parkinson's disease. Despite any differences in reflex size, the inherent muscle stiffness of both muscles appeared to be normal in all groups of patients with Parkinson's disease, since the displacement trajectory of the limb following the force increase was the same as control values in the short (25 ms) period before reflex compensation could intervene. In 20 of the patients and in seven of the control subjects, servo-controlled, ramp positional disturbances were given to the thumb. Up to a velocity of 300°/s, the size of the long-latency stretch reflex was proportional to the log velocity of stretch. This technique revealed, in both moderately and severely rigid patients, increases in the reflex sensitivity of the flexor pollicis longus, which had not been clear using step torque stretches alone. However, whether using ramp or step displacements, long latency stretch reflex gain was not closely related to

Rumination predicts longer sleep onset latency after an acute psychosocial stressor.

PubMed

Zoccola, Peggy M; Dickerson, Sally S; Lam, Suman

2009-09-01

Rumination has been linked to self-reported sleep quality. However, whether rumination is related to an objective sleep parameter has not been tested. This study examined whether rumination predicts sleep onset latency (SOL) on the night after an acute psychosocial stressor. We hypothesized that those who ruminate (assessed with both trait and stressor-specific measures) would have longer SOL (assessed with objective and subjective methods). Seventy participants delivered a 5-minute speech in front of an evaluative panel during an afternoon laboratory session. Trait rumination was assessed before the stressor. Stressor-specific rumination was captured with the frequency of task-related thoughts participants experienced during a 10-minute rest period after the stressor. Participants wore actigraphs on their wrists on the night after the laboratory session to measure objective sleep onset latency (SOL-O). Subjective sleep onset latency was estimated by participants on the subsequent morning. Consistent with hypotheses, trait and stressor-specific rumination predicted longer SOL-O and subjective sleep onset latency, respectively. In addition, trait and stressor-specific rumination interacted to predict longer SOL-O. SOL-O was longest among those who engaged in more stressor-specific rumination and had greater trait rumination scores. Neither rumination measure was related to sleep duration or wakefulness after sleep onset. The findings from this study are consistent with previous research linking rumination to subjective sleep quality. The results also suggest that post-stressor ruminative thought may predict delayed sleep onset for those with a propensity for rumination.

The latency validation of the optical link for the ATLAS Liquid Argon Calorimeter Phase-I trigger upgrade

NASA Astrophysics Data System (ADS)

Deng, B.; Xiao, L.; Zhao, X.; Baker, E.; Gong, D.; Guo, D.; He, H.; Hou, S.; Liu, C.; Liu, T.; Sun, Q.; Thomas, J.; Wang, J.; Xiang, A. C.; Yang, D.; Ye, J.; Zhou, W.

2018-05-01

Two optical data link data transmission Application Specific Integrated Circuits (ASICs), the baseline and its backup, have been designed for the ATLAS Liquid Argon (LAr) Calorimeter Phase-I trigger upgrade. The latency of each ASIC and that of its corresponding receiver implemented in a back-end Field-Programmable Gate Array (FPGA) are critical specifications. In this paper, we present the latency measurements and simulation of two ASICs. The measurement results indicate that both ASICs achieve their design goals and meet the latency specifications. The consistency between the simulation and measurements validates the ASIC latency characterization.

Global EOS: exploring the 300-ms-latency region

NASA Astrophysics Data System (ADS)

Mascetti, L.; Jericho, D.; Hsu, C.-Y.

2017-10-01

EOS, the CERN open-source distributed disk storage system, provides the highperformance storage solution for HEP analysis and the back-end for various work-flows. Recently EOS became the back-end of CERNBox, the cloud synchronisation service for CERN users. EOS can be used to take advantage of wide-area distributed installations: for the last few years CERN EOS uses a common deployment across two computer centres (Geneva-Meyrin and Budapest-Wigner) about 1,000 km apart (∼20-ms latency) with about 200 PB of disk (JBOD). In late 2015, the CERN-IT Storage group and AARNET (Australia) set-up a challenging R&D project: a single EOS instance between CERN and AARNET with more than 300ms latency (16,500 km apart). This paper will report about the success in deploy and run a distributed storage system between Europe (Geneva, Budapest), Australia (Melbourne) and later in Asia (ASGC Taipei), allowing different type of data placement and data access across these four sites.

Measurement and analysis of workload effects on fault latency in real-time systems

NASA Technical Reports Server (NTRS)

Woodbury, Michael H.; Shin, Kang G.

1990-01-01

The authors demonstrate the need to address fault latency in highly reliable real-time control computer systems. It is noted that the effectiveness of all known recovery mechanisms is greatly reduced in the presence of multiple latent faults. The presence of multiple latent faults increases the possibility of multiple errors, which could result in coverage failure. The authors present experimental evidence indicating that the duration of fault latency is dependent on workload. A synthetic workload generator is used to vary the workload, and a hardware fault injector is applied to inject transient faults of varying durations. This method makes it possible to derive the distribution of fault latency duration. Experimental results obtained from the fault-tolerant multiprocessor at the NASA Airlab are presented and discussed.

Physiologic correlates to background noise acceptance

NASA Astrophysics Data System (ADS)

Tampas, Joanna; Harkrider, Ashley; Nabelek, Anna

2004-05-01

Acceptance of background noise can be evaluated by having listeners indicate the highest background noise level (BNL) they are willing to accept while following the words of a story presented at their most comfortable listening level (MCL). The difference between the selected MCL and BNL is termed the acceptable noise level (ANL). One of the consistent findings in previous studies of ANL is large intersubject variability in acceptance of background noise. This variability is not related to age, gender, hearing sensitivity, personality, type of background noise, or speech perception in noise performance. The purpose of the current experiment was to determine if individual differences in physiological activity measured from the peripheral and central auditory systems of young female adults with normal hearing can account for the variability observed in ANL. Correlations between ANL and various physiological responses, including spontaneous, click-evoked, and distortion-product otoacoustic emissions, auditory brainstem and middle latency evoked potentials, and electroencephalography will be presented. Results may increase understanding of the regions of the auditory system that contribute to individual noise acceptance.

Resolution of Misconceptions of Latency and Adolescent Sicklers.

ERIC Educational Resources Information Center

Christy-Levine, Diane

Misconceptions regarding sickle cell disease are qualitatively different among latency age patients as compared to adolescents. The evolution and resolution of these misconceptions determine the effectiveness of self-help programs for sickle cell patients. The Mount Sinai Hospital Sickle Cell Counseling Service is a coordinated center for sickle…

Epstein-Barr virus growth/latency III program alters cellular microRNA expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cameron, Jennifer E.; Tulane Cancer Center, Tulane University Health Sciences Center, 1430 Tulane Avenue, SL79, New Orleans, LA 70112; Fewell, Claire

The Epstein-Barr virus (EBV) is associated with lymphoid and epithelial cancers. Initial EBV infection alters lymphocyte gene expression, inducing cellular proliferation and differentiation as the virus transitions through consecutive latency transcription programs. Cellular microRNAs (miRNAs) are important regulators of signaling pathways and are implicated in carcinogenesis. The extent to which EBV exploits cellular miRNAs is unknown. Using micro-array analysis and quantitative PCR, we demonstrate differential expression of cellular miRNAs in type III versus type I EBV latency including elevated expression of miR-21, miR-23a, miR-24, miR-27a, miR-34a, miR-146a and b, and miR-155. In contrast, miR-28 expression was found to be lowermore » in type III latency. The EBV-mediated regulation of cellular miRNAs may contribute to EBV signaling and associated cancers.« less

Evaluation of the relation between triceps surae H-reflex, M-response latencies and thigh length in normal population.

PubMed

Khosrawi, Saeid; Fallah, Salman

2013-03-01

The H-reflex is a useful electrophysiological procedure for evaluating the status of the peripheral nervous system, especially at the proximal segment of the peripheral nerve. The purpose of this study is to investigate the relation between triceps surae H-reflex and M- response latencies and thigh length in normal population, in order to determine if there is any regression equation between them. After screening 75 volunteers by considering inclusion and exclusion criteria, 72 of them were selected to enroll into our study (34 men and 38 women with the mean age of 36.04 ± 7.7 years). In all of the subjects H-reflex and M-response latencies were recorded by standard electrophysiological techniques and thigh length was measured. Finally, our data was analyzed for its relations with respect to ages in both sexes by appropriate statistical and mathematical methods. Mean ± SD for H-reflex latency was 27.94 ± 1.6 ms. We found a significant correlation between H-reflex latency and M-latency (r = 0.28), no significant correlation was found between H-reflex latency and thigh length (r = -0.051). Finally based on our findings we introduce a new formula in this paper. We found a significant correlation among of M-response latency and other variables (H-reflex latency and thigh length). Despite this it was eliminated from our formula. The relationship between H-reflex latency and age was significant. Further studies are required to delineate the clinical usage and interpretation of the formula, which we found in this study.

Latency Determination and Compensation in Real-Time Gnss/ins Integrated Navigation Systems

NASA Astrophysics Data System (ADS)

Solomon, P. D.; Wang, J.; Rizos, C.

2011-09-01

Unmanned Aerial Vehicle (UAV) technology is now commonplace in many defence and civilian environments. However, the high cost of owning and operating a sophisticated UAV has slowed their adoption in many commercial markets. Universities and research groups are actively experimenting with UAVs to further develop the technology, particularly for automated flying operations. The two main UAV platforms used are fixed-wing and helicopter. Helicopter-based UAVs offer many attractive features over fixed-wing UAVs, including vertical take-off, the ability to loiter, and highly dynamic flight. However the control and navigation of helicopters are significantly more demanding than those of fixed-wing UAVs and as such require a high bandwidth real-time Position, Velocity, Attitude (PVA) navigation system. In practical Real-Time Navigation Systems (RTNS) there are delays in the processing of the GNSS data prior to the fusion of the GNSS data with the INS measurements. This latency must be compensated for otherwise it degrades the solution of the navigation filter. This paper investigates the effect of latency in the arrival time of the GNSS data in a RTNS. Several test drives and flights were conducted with a low-cost RTNS, and compared with a high quality GNSS/INS solution. A technique for the real-time, automated and accurate estimation of the GNSS latency in low-cost systems was developed and tested. The latency estimates were then verified through cross-correlation with the time-stamped measurements from the reference system. A delayed measurement Extended Kalman Filter was then used to allow for the real-time fusing of the delayed measurements, and then a final system developed for on-the-fly measurement and compensation of GNSS latency in a RTNS.

HyspIRI Low Latency Concept and Benchmarks

NASA Technical Reports Server (NTRS)

Mandl, Dan

2010-01-01

Topics include HyspIRI low latency data ops concept, HyspIRI data flow, ongoing efforts, experiment with Web Coverage Processing Service (WCPS) approach to injecting new algorithms into SensorWeb, low fidelity HyspIRI IPM testbed, compute cloud testbed, open cloud testbed environment, Global Lambda Integrated Facility (GLIF) and OCC collaboration with Starlight, delay tolerant network (DTN) protocol benchmarking, and EO-1 configuration for preliminary DTN prototype.

Auditory Magnetic Mismatch Field Latency: A Biomarker for Language Impairment in Autism

PubMed Central

Roberts, Timothy P.L.; Cannon, Katelyn M.; Tavabi, Kambiz; Blaskey, Lisa; Khan, Sarah Y.; Monroe, Justin F.; Qasmieh, Saba; Levy, Susan E.; Edgar, J. Christopher

2011-01-01

Background Auditory processing abnormalities are frequently observed in Autism Spectrum Disorders (ASD), and these abnormalities may have sequelae in terms of clinical language impairment (LI). The present study assessed associations between language impairment and the amplitude and latency of the superior temporal gyrus magnetic mismatch field (MMF) in response to changes in an auditory stream of tones or vowels. Methods 51 children with ASD and 27 neurotypical controls, all aged 6-15 years, underwent neuropsychological evaluation, including tests of language function, as well as magnetoencephalographic (MEG) recording during presentation of tones and vowels. The MMF was identified in the difference waveform obtained from subtraction of responses to standard stimuli from deviant stimuli. Results MMF latency was significantly prolonged (p<0.001) in children with ASD compared to neurotypical controls. Furthermore, this delay was most pronounced (∼50ms) in children with concomitant LI, with significant differences in latency between children with ASD with LI and those without (p<0.01). Receiver operator characteristic analysis indicated a sensitivity of 82.4% and specificity of 71.2% for diagnosing LI based on MMF latency. Conclusion Neural correlates of auditory change detection (the MMF) are significantly delayed in children with ASD, and especially those with concomitant LI suggesting both a neurobiological basis for LI as well as a clinical biomarker for LI in ASD. PMID:21392733

Amplitude, Latency, and Peak Velocity in Accommodation and Disaccommodation Dynamics

PubMed Central

Papadatou, Eleni; Ferrer-Blasco, Teresa; Montés-Micó, Robert

2017-01-01

The aim of this work was to ascertain whether there are differences in amplitude, latency, and peak velocity of accommodation and disaccommodation responses when different analysis strategies are used to compute them, such as fitting different functions to the responses or for smoothing them prior to computing the parameters. Accommodation and disaccommodation responses from four subjects to pulse changes in demand were recorded by means of aberrometry. Three different strategies were followed to analyze such responses: fitting an exponential function to the experimental data; fitting a Boltzmann sigmoid function to the data; and smoothing the data. Amplitude, latency, and peak velocity of the responses were extracted. Significant differences were found between the peak velocity in accommodation computed by fitting an exponential function and smoothing the experimental data (mean difference 2.36 D/s). Regarding disaccommodation, significant differences were found between latency and peak velocity, calculated with the two same strategies (mean difference of 0.15 s and −3.56 D/s, resp.). The strategy used to analyze accommodation and disaccommodation responses seems to affect the parameters that describe accommodation and disaccommodation dynamics. These results highlight the importance of choosing the most adequate analysis strategy in each individual to obtain the parameters that characterize accommodation and disaccommodation dynamics. PMID:29226128

Mid-latency evoked potentials in self-reported impulsive aggression.

PubMed

Houston, R J; Stanford, M S

2001-02-01

The present study was conducted to examine psychophysiological differences in arousability among individuals who display impulsive aggressive outbursts. Amplitude and latency for the mid-latency evoked potentials (P1, N1 and P2) were obtained at scalp electrode sites. The evoking stimuli were three intensities (low, medium, high) of photic stimulation. Compared to non-aggressive controls, impulsive aggressive subjects showed significantly reduced P1 amplitude, which is indicative of an inefficient sensory gating mechanism. In addition, these subjects exhibited significantly larger N1 amplitude implying an enhanced orienting of attention to stimuli. Impulsive aggressive subjects also exhibited shorter P1, N1 and P2 peak latency. These results suggest that impulsive aggressive individuals may display quicker orienting and processing of stimuli in an attempt to compensate for low resting arousal levels. Finally, impulsive aggressive subjects augmented the P1-N1 component more frequently than controls, which is consistent with previous studies examining impulsivity and sensation seeking. Together, these findings extend previous work concerning the underlying physiology of impulsive aggression. It has been suggested that impulsive aggressive individuals may attempt to compensate for low resting arousal levels by engaging in stimulus seeking behaviors. Accordingly, the present findings imply similar physiological compensatory responses as demonstrated by heightened orienting of attention, processing and arousability. In addition, a compromised sensory gating system in impulsive aggressors may exacerbate such circumstances, and lead to later cognitive processing deficits.

A 2.5-Kilobase Deletion Containing a Cluster of Nine MicroRNAs in the Latency-Associated-Transcript Locus of the Pseudorabies Virus Affects the Host Response of Porcine Trigeminal Ganglia during Established Latency

PubMed Central

Mahjoub, Nada; Dhorne-Pollet, Sophie; Fuchs, Walter; Endale Ahanda, Marie-Laure; Lange, Elke; Klupp, Barbara; Arya, Anoop; Loveland, Jane E.; Lefevre, François; Mettenleiter, Thomas C.

2014-01-01

ABSTRACT The alphaherpesvirus pseudorabies virus (PrV) establishes latency primarily in neurons of trigeminal ganglia when only the transcription of the latency-associated transcript (LAT) locus is detected. Eleven microRNAs (miRNAs) cluster within the LAT, suggesting a role in establishment and/or maintenance of latency. We generated a mutant (M) PrV deleted of nine miRNA genes which displayed properties that were almost identical to those of the parental PrV wild type (WT) during propagation in vitro. Fifteen pigs were experimentally infected with either WT or M virus or were mock infected. Similar levels of virus excretion and host antibody response were observed in all infected animals. At 62 days postinfection, trigeminal ganglia were excised and profiled by deep sequencing and quantitative RT-PCR. Latency was established in all infected animals without evidence of viral reactivation, demonstrating that miRNAs are not essential for this process. Lower levels of the large latency transcript (LLT) were found in ganglia infected by M PrV than in those infected by WT PrV. All PrV miRNAs were expressed, with highest expression observed for prv-miR-LLT1, prv-miR-LLT2 (in WT ganglia), and prv-miR-LLT10 (in both WT and M ganglia). No evidence of differentially expressed porcine miRNAs was found. Fifty-four porcine genes were differentially expressed between WT, M, and control ganglia. Both viruses triggered a strong host immune response, but in M ganglia gene upregulation was prevalent. Pathway analyses indicated that several biofunctions, including those related to cell-mediated immune response and the migration of dendritic cells, were impaired in M ganglia. These findings are consistent with a function of the LAT locus in the modulation of host response for maintaining a latent state. IMPORTANCE This study provides a thorough reference on the establishment of latency by PrV in its natural host, the pig. Our results corroborate the evidence obtained from the study

Middle Latency Auditory Evoked Potential (MLAEP) in Workers with and without Tinnitus who are Exposed to Occupational Noise.

PubMed

dos Santos Filha, Valdete Alves Valentins; Samelli, Alessandra Giannella; Matas, Carla Gentile

2015-09-11

Tinnitus is an important occupational health concern, but few studies have focused on the central auditory pathways of workers with a history of occupational noise exposure. Thus, we analyzed the central auditory pathways of workers with a history of occupational noise exposure who had normal hearing threshold, and compared middle latency auditory evoked potential in those with and without noise-induced tinnitus. Sixty individuals (30 with and 30 without tinnitus) underwent the following procedures: anamnesis, immittance measures, pure-tone air conduction thresholds at all frequencies between 0.25-8 kHz, and middle latency auditory evoked potentials. Quantitative analysis of latencies and amplitudes of middle latency auditory evoked potential showed no significant differences between the groups with and without tinnitus. In the qualitative analysis, we found that both groups showed increased middle latency auditory evoked potential latencies. The study group had more alterations of the "both" type regarding the Na-Pa amplitude, while the control group had more "electrode effect" alterations, but these alterations were not significantly different when compared to controls. Individuals with normal hearing with or without tinnitus who are exposed to occupational noise have altered middle latency auditory evoked potential, suggesting impairment of the auditory pathways in cortical and subcortical regions. Although differences did not reach significance, individuals with tinnitus seemed to have more abnormalities in components of the middle latency auditory evoked potential when compared to individuals without tinnitus, suggesting alterations in the generation and transmission of neuroelectrical impulses along the auditory pathway.

Validation of prospective portion size and latency to eat as measures of reactivity to snack foods.

PubMed

van den Akker, Karolien; Bongers, Peggy; Hanssen, Imke; Jansen, Anita

2017-09-01

In experimental studies that investigate reactivity to the sight and smell of highly palatable snack foods, ad libitum food intake is commonly used as a behavioural outcome measure. However, this measure has several drawbacks. The current study investigated two intake-related measures not yet validated for food cue exposure research involving common snack foods: prospective portion size and latency to eat. We aimed to validate these measures by assessing prospective portion size and eating latencies in female undergraduate students who either underwent snack food exposure or a control exposure. Furthermore, we correlated prospective portion size and latency to eat with commonly used measures of food cue reactivity, i.e., self-reported desire to eat, salivation, and ad libitum food intake. Results showed increases in prospective portion size after food cue exposure but not after control exposure. Latency to eat did not differ between the two conditions. Prospective portion size correlated positively with desire to eat and food intake, and negatively with latency to eat. Latency to eat was also negatively correlated with desire to eat and food intake. It is concluded that the current study provides initial evidence for the prospective portion size task as a valid measure of reactivity to snack foods in a Dutch female and mostly healthy weight student population. Copyright © 2017 Elsevier Ltd. All rights reserved.

Test-retest reliability of the multiple sleep latency test in narcolepsy without cataplexy and idiopathic hypersomnia.

PubMed

Trotti, Lynn Marie; Staab, Beth A; Rye, David B

2013-08-15

Differentiation of narcolepsy without cataplexy from idiopathic hypersomnia relies entirely upon the multiple sleep latency test (MSLT). However, the test-retest reliability for these central nervous system hypersomnias has never been determined. Patients with narcolepsy without cataplexy, idiopathic hypersomnia, and physiologic hypersomnia who underwent two diagnostic multiple sleep latency tests were identified retrospectively. Correlations between the mean sleep latencies on the two studies were evaluated, and we probed for demographic and clinical features associated with reproducibility versus change in diagnosis. Thirty-six patients (58% women, mean age 34 years) were included. Inter -test interval was 4.2 ± 3.8 years (range 2.5 months to 16.9 years). Mean sleep latencies on the first and second tests were 5.5 (± 3.7 SD) and 7.3 (± 3.9) minutes, respectively, with no significant correlation (r = 0.17, p = 0.31). A change in diagnosis occurred in 53% of patients, and was accounted for by a difference in the mean sleep latency (N = 15, 42%) or the number of sleep onset REM periods (N = 11, 31%). The only feature predictive of a diagnosis change was a history of hypnagogic or hypnopompic hallucinations. The multiple sleep latency test demonstrates poor test-retest reliability in a clinical population of patients with central nervous system hypersomnia evaluated in a tertiary referral center. Alternative diagnostic tools are needed.

The effect of preterm birth on brainstem, middle latency and cortical auditory evoked responses (BMC AERs).

PubMed

Pasman, J W; Rotteveel, J J; de Graaf, R; Stegeman, D F; Visco, Y M

1992-12-01

Recent studies on the maturation of auditory brainstem evoked responses (ABRs) present conflicting results, whereas only sparse reports exist with respect to the maturation of middle latency auditory evoked responses (MLRs) and auditory cortical evoked responses (ACRs). The present study reports the effect of preterm birth on the maturation of auditory evoked responses in low risk preterm infants (27-34 weeks conceptional age). The ABRs indicate a consistent trend towards longer latencies for all individual ABR components and towards longer interpeak latencies in preterm infants. The MLR shows longer latencies for early component P0 in preterm infants. The ACRs show a remarkable difference between preterm and term infants. At 40 weeks CA the latencies of ACR components Na and P2 are significantly longer in term infants, whereas at 52 weeks CA the latencies of the same ACR components are shorter in term infants. The results support the hypothesis that retarded myelination of the central auditory pathway is partially responsible for differences found between preterm infants and term infants with respect to late ABR components and early MLR component P0. Furthermore, mild conductive hearing loss in preterm infants may also play its role. A more complex mechanism is implicated to account for the findings noted with respect to MLR component Na and ACR components Na and P2.

Test-Retest Reliability of the Multiple Sleep Latency Test in Narcolepsy without Cataplexy and Idiopathic Hypersomnia

PubMed Central

Trotti, Lynn Marie; Staab, Beth A.; Rye, David B.

2013-01-01

Study Objectives: Differentiation of narcolepsy without cataplexy from idiopathic hypersomnia relies entirely upon the multiple sleep latency test (MSLT). However, the test-retest reliability for these central nervous system hypersomnias has never been determined. Methods: Patients with narcolepsy without cataplexy, idiopathic hypersomnia, and physiologic hypersomnia who underwent two diagnostic multiple sleep latency tests were identified retrospectively. Correlations between the mean sleep latencies on the two studies were evaluated, and we probed for demographic and clinical features associated with reproducibility versus change in diagnosis. Results: Thirty-six patients (58% women, mean age 34 years) were included. Inter -test interval was 4.2 ± 3.8 years (range 2.5 months to 16.9 years). Mean sleep latencies on the first and second tests were 5.5 (± 3.7 SD) and 7.3 (± 3.9) minutes, respectively, with no significant correlation (r = 0.17, p = 0.31). A change in diagnosis occurred in 53% of patients, and was accounted for by a difference in the mean sleep latency (N = 15, 42%) or the number of sleep onset REM periods (N = 11, 31%). The only feature predictive of a diagnosis change was a history of hypnagogic or hypnopompic hallucinations. Conclusions: The multiple sleep latency test demonstrates poor test-retest reliability in a clinical population of patients with central nervous system hypersomnia evaluated in a tertiary referral center. Alternative diagnostic tools are needed. Citation: Trotti LM; Staab BA; Rye DB. Test- retest reliability of the multiple sleep latency test in narcolepsy without cataplexy and idiopathic hypersomnia. J Clin Sleep Med 2013;9(8):789-795. PMID:23946709

Coregulatory Interactions among CD8α Dendritic Cells, the Latency-Associated Transcript, and Programmed Death 1 Contribute to Higher Levels of Herpes Simplex Virus 1 Latency

PubMed Central

Mott, Kevin R.; Allen, Sariah J.; Zandian, Mandana

2014-01-01

ABSTRACT The latency-associated transcript (LAT) of herpes simplex virus 1 (HSV-1), CD8α+ dendritic cells (DCs), and programmed death 1 (PD-1) have all been implicated in the HSV-1 latency-reactivation cycle. It is not known, however, whether an interaction between LAT and CD8α+ DCs regulates latency and T-cell exhaustion. To address this question, we used LAT-expressing [LAT(+)] and LAT-negative [LAT(−)] viruses. Depletion of DCs in mice ocularly infected with LAT(+) virus resulted in a reduction in the number of T cells expressing PD-1 in the trigeminal ganglia (TG), whereas depletion of DCs in mice similarly infected with LAT(−) virus did not alter PD-1 expression. CD8α+ DCs, but not CD4+ DCs, infected with LAT(+) virus had higher levels of ICP0, ICP4, thymidine kinase (TK), and PD-1 ligand 1 (PD-L1) transcripts than those infected with LAT(−) virus. Coculture of infected bone marrow (BM)-derived DCs from wild-type (WT) mice, but not infected DCs from CD8α−/− mice, with WT naive T cells contributed to an increase in PD-1 expression. Transfer of bone marrow from WT mice but not CD8α−/− mice to recipient Rag1−/− mice increased the number of latent viral genomes in reconstituted mice infected with the LAT(+) virus. Collectively, these data indicated that a reduction in latency correlated with a decline in the levels of CD8α+ DCs and PD-1 expression. In summary, our results demonstrate an interaction among LAT, PD-1, and CD11c CD8α+ cells that regulates latency in the TG of HSV-1-infected mice. IMPORTANCE Very little is known regarding the interrelationship of LAT, PD-1, and CD8α+ DCs and how such interactions might contribute to relative numbers of latent viral genomes. We show here that (i) in both in vivo and in vitro studies, deficiency of CD8α+ DCs significantly reduced T-cell exhaustion in the presence of LAT(+) virus but not LAT(−) virus; (ii) HSV-1 infectivity was significantly lower in LAT(−)-infected DCs than in their LAT

The rate and latency of star formation in dense, massive clumps in the Milky Way

NASA Astrophysics Data System (ADS)

Heyer, M.; Gutermuth, R.; Urquhart, J. S.; Csengeri, T.; Wienen, M.; Leurini, S.; Menten, K.; Wyrowski, F.

2016-04-01

Context. Newborn stars form within the localized, high density regions of molecular clouds. The sequence and rate at which stars form in dense clumps and the dependence on local and global environments are key factors in developing descriptions of stellar production in galaxies. Aims: We seek to observationally constrain the rate and latency of star formation in dense massive clumps that are distributed throughout the Galaxy and to compare these results to proposed prescriptions for stellar production. Methods: A sample of 24 μm-based Class I protostars are linked to dust clumps that are embedded within molecular clouds selected from the APEX Telescope Large Area Survey of the Galaxy. We determine the fraction of star-forming clumps, f∗, that imposes a constraint on the latency of star formation in units of a clump's lifetime. Protostellar masses are estimated from models of circumstellar environments of young stellar objects from which star formation rates are derived. Physical properties of the clumps are calculated from 870 μm dust continuum emission and NH3 line emission. Results: Linear correlations are identified between the star formation rate surface density, ΣSFR, and the quantities ΣH2/τff and ΣH2/τcross, suggesting that star formation is regulated at the local scales of molecular clouds. The measured fraction of star forming clumps is 23%. Accounting for star formation within clumps that are excluded from our sample due to 24 μm saturation, this fraction can be as high as 31%, which is similar to previous results. Dense, massive clumps form primarily low mass (<1-2 M⊙) stars with emergent 24 μm fluxes below our sensitivity limit or are incapable of forming any stars for the initial 70% of their lifetimes. The low fraction of star forming clumps in the Galactic center relative to those located in the disk of the Milky Way is verified. Full Tables 2-4 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130

Long-latency neurodegenerative disease in the western Pacific.

PubMed

Spencer, P S; Kisby, G E; Ludolph, A C

1991-08-01

The western Pacific parkinsonism-dementia and amyotrophic lateral sclerosis complex is a prototypical neurodegenerative disorder found among inhabitants of Guam, New Guinea (Irian Jaya, Indonesia) and Japan (Kii Peninsula, Honshu). Nonviral environmental factors peculiar to the affected populations seem to play a prominent etiologic role. Although cause-effect relationships cannot be established by epidemiologic studies alone, we have shown in all three affected population groups that individuals develop the amyotrophic lateral sclerosis variant of this disorder after heavy exposure to the raw or incompletely detoxified seed of neurotoxic cycad plants. Since long periods may elapse between cycad exposure and the appearance of neurological disease in humans, cycads may harbor a "slow toxin" that causes the postmitotic neuron to undergo slow irreversible degeneration. Two cycad neurotoxins are recognized, one of which (cycasin) is known to have long-latency effects (tumorigenesis) on mitotic neurons and replicating cells in other tissues. This paper explores the possible relationship between tumorigenesis and long-latency neurotoxicity, and discusses possible biologic markers of cycad exposure and subclinical neurodegenerative disease.

Perceptual latency priming by masked and unmasked stimuli: evidence for an attentional interpretation.

PubMed

Scharlau, Ingrid; Neumann, Odmar

2003-08-01

Four experiments investigated the influence of a metacontrast-masked prime on temporal order judgments. The main results were (1) that a masked prime reduced the latency of the mask's conscious perception (perceptual latency priming), (2) that this effect was independent of whether the prime suffered strong or weak masking, (3) that it was unaffected by the degree of visual similarity between the prime and the mask, and that (4) there was no difference between congruent and incongruent primes. Finding (1) suggests that location cueing affects not only response times but also the latency of conscious perception. (2) The finding that priming was unaffected by the prime's detectability argues against a response bias interpretation of this effect. (3) Since visual similarity had no effect on the prime's efficiency, it is unlikely that sensory priming was involved. (4) The lack of a divergence between the effects of congruent and incongruent primes implies a functional difference between the judgments in the temporal order judgment task and speeded responses that have demonstrated differential effects of congruent and incongruent primes (e.g., Klotz & Neumann, 1999). These results can best be interpreted by assuming that the prime affects perceptual latency by initiating a shift of attention, as suggested by the Asynchronous Updating Model (AUM; Neumann 1978, 1982).

Memory-dependent adjustment of vocal response latencies in a territorial songbird.

PubMed

Geberzahn, Nicole; Hultsch, Henrike; Todt, Dietmar

2013-06-01

Vocal interactions in songbirds can be used as a model system to investigate the interplay of intrinsic singing programmes (e.g. influences from vocal memories) and external variables (e.g. social factors). When characterizing vocal interactions between territorial rivals two aspects are important: (1) the timing of songs in relation to the conspecific's singing and (2) the use of a song pattern that matches the rival's song. Responses in both domains can be used to address a territorial rival. This study is the first to investigate the relation of the timing of vocal responses to (1) the vocal memory of a responding subject and (2) the selection of the song pattern that the subject uses as a response. To this end, we conducted interactive playback experiments with adult nightingales (Luscinia megarhynchos) that had been hand-reared and tutored in the laboratory. We analysed the subjects' vocal response latencies towards broadcast playback stimuli that they either had in their own vocal repertoire (songs shared with playback) or that they had not heard before (unknown songs). Likewise, we compared vocal response latencies between responses that matched the stimulus song and those that did not. Our findings showed that the latency of singing in response to the playback was shorter for shared versus unknown song stimuli when subjects overlapped the playback stimuli with their own song. Moreover birds tended to overlap faster when vocally matching the stimulus song rather than when replying with a non-matching song type. We conclude that memory of song patterns influenced response latencies and discuss possible mechanisms. Copyright © 2012 Elsevier Ltd. All rights reserved.

Rewards modulate saccade latency but not exogenous spatial attention.

PubMed

Dunne, Stephen; Ellison, Amanda; Smith, Daniel T

2015-01-01

The eye movement system is sensitive to reward. However, whilst the eye movement system is extremely flexible, the extent to which changes to oculomotor behavior induced by reward paradigms persist beyond the training period or transfer to other oculomotor tasks is unclear. To address these issues we examined the effects of presenting feedback that represented small monetary rewards to spatial locations on the latency of saccadic eye movements, the time-course of learning and extinction of the effects of rewarding saccades on exogenous spatial attention and oculomotor inhibition of return. Reward feedback produced a relative facilitation of saccadic latency in a stimulus driven saccade task which persisted for three blocks of extinction trials. However, this hemifield-specific effect failed to transfer to peripheral cueing tasks. We conclude that rewarding specific spatial locations is unlikely to induce long-term, systemic changes to the human oculomotor or attention systems.

HIV-1 transcription and latency: an update

PubMed Central

2013-01-01

Combination antiretroviral therapy, despite being potent and life-prolonging, is not curative and does not eradicate HIV-1 infection since interruption of treatment inevitably results in a rapid rebound of viremia. Reactivation of latently infected cells harboring transcriptionally silent but replication-competent proviruses is a potential source of persistent residual viremia in cART-treated patients. Although multiple reservoirs may exist, the persistence of resting CD4+ T cells carrying a latent infection represents a major barrier to eradication. In this review, we will discuss the latest reports on the molecular mechanisms that may regulate HIV-1 latency at the transcriptional level, including transcriptional interference, the role of cellular factors, chromatin organization and epigenetic modifications, the viral Tat trans-activator and its cellular cofactors. Since latency mechanisms may also operate at the post-transcriptional level, we will consider inhibition of nuclear RNA export and inhibition of translation by microRNAs as potential barriers to HIV-1 gene expression. Finally, we will review the therapeutic approaches and clinical studies aimed at achieving either a sterilizing cure or a functional cure of HIV-1 infection, with a special emphasis on the most recent pharmacological strategies to reactivate the latent viruses and decrease the pool of viral reservoirs. PMID:23803414

Low-Latency Teleoperations for Human Exploration and Evolvable Mars Campaign

NASA Technical Reports Server (NTRS)

Lupisella, Mark; Wright, Michael; Arney, Dale; Gershman, Bob; Stillwagen, Fred; Bobskill, Marianne; Johnson, James; Shyface, Hilary; Larman, Kevin; Lewis, Ruthan;

Mid-latency auditory evoked potential response revealed as an evidence of neural plasticity in blinnd individuals.

PubMed

Muthusamy, Anbarasi; Gajendran, Rajkumar; Rao B, Vishwanatha

2014-01-01

There is a general impression that visually blind individuals show an exceptionally better perception of other sensory modalities such as hearing, touch and smell sensations. In this study, we intended to compare the mid-latency auditory evoked potential response (MLAEP) or Middle latency Response (MLR) to get an idea of the activity pattern of auditory thalamus and cortex between 30 visually handicapped subjects and 30 normal sighted subjects. The results showed a decrease in many of the MLR wave latencies, but highly significant for the wave Pa (P value <0.002). This fact can be reflected as an evidence of existence of cross-modal neuroplasticity. We also inferred that there are significant gender differences with latencies shorter in males than females (P value <0.02) in the blind subjects group which could be attributed to their rehabilitation training.

A Simulation Base Investigation of High Latency Space Systems Operations

NASA Technical Reports Server (NTRS)

Li, Zu Qun; Crues, Edwin Z.; Bielski, Paul; Moore, Michael

2017-01-01

NASA's human space program has developed considerable experience with near Earth space operations. Although NASA has experience with deep space robotic missions, NASA has little substantive experience with human deep space operations. Even in the Apollo program, the missions lasted only a few weeks and the communication latencies were on the order of seconds. Human missions beyond the relatively close confines of the Earth-Moon system will involve missions with durations measured in months and communications latencies measured in minutes. To minimize crew risk and to maximize mission success, NASA needs to develop a better understanding of the implications of these types of mission durations and communication latencies on vehicle design, mission design and flight controller interaction with the crew. To begin to address these needs, NASA performed a study using a physics-based subsystem simulation to investigate the interactions between spacecraft crew and a ground-based mission control center for vehicle subsystem operations across long communication delays. The simulation, built with a subsystem modeling tool developed at NASA's Johnson Space Center, models the life support system of a Mars transit vehicle. The simulation contains models of the cabin atmosphere and pressure control system, electrical power system, drinking and waste water systems, internal and external thermal control systems, and crew metabolic functions. The simulation has three interfaces: 1) a real-time crew interface that can be use to monitor and control the vehicle subsystems; 2) a mission control center interface with data transport delays up to 15 minutes each way; 3) a real-time simulation test conductor interface that can be use to insert subsystem malfunctions and observe the interactions between the crew, ground, and simulated vehicle. The study was conducted at the 21st NASA Extreme Environment Mission Operations (NEEMO) mission between July 18th and Aug 3rd of year 2016. The NEEMO

Apparatus for fixing latency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hall, David R; Bartholomew, David B; Moon, Justin

2009-09-08

An apparatus for fixing computational latency within a deterministic region on a network comprises a network interface modem, a high priority module and at least one deterministic peripheral device. The network interface modem is in communication with the network. The high priority module is in communication with the network interface modem. The at least one deterministic peripheral device is connected to the high priority module. The high priority module comprises a packet assembler/disassembler, and hardware for performing at least one operation. Also disclosed is an apparatus for executing at least one instruction on a downhole device within a deterministic region,more » the apparatus comprising a control device, a downhole network, and a downhole device. The control device is near the surface of a downhole tool string. The downhole network is integrated into the tool string. The downhole device is in communication with the downhole network.« less

Effects of N-acetylcysteine on noise-induced temporary threshold shift and temporary emission shift

NASA Astrophysics Data System (ADS)

Robinette, Martin

2004-05-01

Animal research has shown that antioxidants can provide significant protection to the cochlea from traumatic noise exposure with some benefit when given after the exposure. Similar results in humans would have a significant impact on both prevention and treatment of noise-induced hearing loss. The current study evaluates the effectiveness of N-acetylcysteine (NAC) on temporary threshold shift (TTS) by using both behavioral and physiological measures. Sixteen healthy, normal-hearing subjects were given NAC or a placebo prior to exposure to a 10-min, 102-dB narrow-band noise, centered at 2 kHz. This exposure was designed to induce a 10-15-dB TTS. Following the noise exposure, pure-tone thresholds (Bekesy) and transient-evoked otoacoustic emissions (TEOAE) were measured for 60 min to monitor the effects of NAC on TTS recovery. Postexposure measures were compared to baseline data. [Work supported by American BioHealth Group.

Short latency vestibular evoked potentials in the Japanese quail (Coturnix coturnix japonica)

NASA Technical Reports Server (NTRS)

Jones, S. M.; Jones, T. A.; Shukla, R.

1997-01-01

Short-latency vestibular-evoked potentials to pulsed linear acceleration were characterized in the quail. Responses occurred within 8 ms following the onset of stimuli and were composed of a series of positive and negative peaks. The latencies and amplitudes of the first four peaks were quantitatively characterized. Mean latencies at 1.0 g ms-1 ranged from 1265 +/- 208 microseconds (P1, N = 18) to 4802 +/- 441 microseconds (N4, N = 13). Amplitudes ranged from 3.72 +/- 1.51 microV (P1/N1, N = 18) to 1.49 +/- 0.77 microV (P3/N3, N = 16). Latency-intensity (LI) slopes ranged from -38.7 +/- 7.3 microseconds dB-1 (P1, N = 18) to -71.6 +/- 21.9 microseconds dB-1 (N3, N = 15) and amplitude-intensity (AI) slopes ranged from 0.20 +/- 0.08 microV dB-1 (P1/N1, N = 18) to 0.07 +/- 0.04 microV dB-1 (P3/N3, N = 11). The mean response threshold across all animals was -21.83 +/- 3.34 dB re: 1.0 g ms-1 (N = 18). Responses remained after cochlear extirpation showing that they could not depend critically on cochlear activity. Responses were eliminated by destruction of the vestibular end organs, thus showing that responses depended critically and specifically on the vestibular system. The results demonstrate that the responses are vestibular and the findings provide a scientific basis for using vestibular responses to evaluate vestibular function through ontogeny and senescence in the quail.

Judgment and judgment latency for freedom and responsibility relatedness as a function of subtle linguistic variations.

PubMed

Wilkerson, Keith; McGahan, Joseph R; Stevens, Rick; Williamson, David; Low, Jean

2009-12-01

The goal of this study was to determine whether differential response formats to covariation problems influence corresponding response latencies. The authors provided participants with 3 trials of 16 statements addressing positive and negative relations between freedom and responsibility. The authors framed half of the items around responsibility given freedom and the other half around freedom given responsibility. Response formats comprised true-false, agree-disagree, and yes-no answers as a between-participants factor. Results indicated that the manipulation of response format did not affect latencies. However, latencies differed according to the framing of the items. For items framed around freedom given responsibility, latencies were shorter. In addition, participants were more likely to report a positive relation between freedom and responsibility when items were framed around freedom given responsibility. The authors discuss implications relative to previous research in this area and give recommendations for future research.

Interside Latency Differences in Brainstem Auditory and Somatosensory Evoked Potentials. Defining Upper Limits to Determine Asymmetry.

PubMed

Moncho, Dulce; Poca, Maria A; Minoves, Teresa; Ferré, Alejandro; Sahuquillo, Juan

2015-10-01

Limits of the interside differences are invaluable when interpreting asymmetry in brainstem auditory evoked potentials and somatosensory evoked potentials (SEP) recordings. The aim of this study was to analyze the normal upper limits of interside latency differences of brainstem auditory evoked potentials and SEP from the posterior tibial nerve and median nerve to determine asymmetry. The authors performed a prospective study in 56 healthy subjects aged 15 to 64 years with no neurological or hearing disorders. They analyzed (1) the latencies of I, III, and V waves and I-III, III-V, and I-V intervals and the amplitude ratios V/I and IV/I for brainstem auditory evoked potentials bilaterally; (2) the latencies of N8, N22, N28, and P37 waves and the interval N22-P37 and the amplitude P37 for posterior tibial nerve SEP bilaterally; and (3) the latencies and amplitudes of N9, N13, and N20 waves and N9-N13 and N13-N20 intervals for median nerve SEP bilaterally. The interside differences for these parameters were calculated and analyzed. The authors obtained an upper limit for the interside latency differences from brainstem auditory evoked potentials that was significantly lower than the previously published data. However, the upper limits of interside latency differences for SEP were similar to those previously reported. The findings of this study should be considered when laboratories analyze asymmetry using the normative data published by another center, however temporarily, in organizing new laboratories.

Communication latencies of Apple push notification messages relevant for delivery of time-critical information to anesthesia providers.

PubMed

Rothman, Brian S; Dexter, Franklin; Epstein, Richard H

2013-08-01

Tablet computers and smart phones have gained popularity in anesthesia departments for educational and patient care purposes. VigiVU(™) is an iOS application developed at Vanderbilt University for remote viewing of perioperative information, including text message notifications delivered via the Apple Push Notification (APN) service. In this study, we assessed the reliability of the APN service. Custom software was written to send a message every minute to iOS devices (iPad(®), iPod Touch(®), and iPhone(®)) via wireless local area network (WLAN) and cellular pathways 24 hours a day over a 4-month period. Transmission and receipt times were recorded and batched by days, with latencies calculated as their differences. The mean, SEM, and the exact 95% upper confidence limits for the percent of days with ≥1 prolonged (>100 seconds) latency were calculated. Acceptable performance was defined as mean latency <30 seconds and ≤0.5% of latencies >100 seconds. Testing conditions included fixed locations of devices in high signal strength locations. Mean latencies were <1 second for iPad and iPod devices (WLAN), and <4 seconds for iPhone (cellular). Among >173,000 iPad and iPod latencies, none were >100 seconds. For iPhone latencies, 0.03% ± 0.01% were >100 seconds. The 95% upper confidence limits of days with ≥1 prolonged latency were 42% (iPhone) and 5% to 8% (iPad, iPod). The APN service was reliable for all studied devices over WLAN and cellular pathways, and performance was better than third party paging systems using Internet connections previously investigated using the same criteria. However, since our study was a best-case assessment, testing is required at individual sites considering use of this technology for critical messaging. Furthermore, since the APN service may fail due to Internet or service provider disruptions, a backup paging system is recommended if the APN service were to be used for critical messaging.

Importance of latency and amplitude values of recurrent laryngeal nerve during thyroidectomy in diabetic patients.

PubMed

Ozemir, Ibrahim Ali; Ozyalvac, Ferman; Yildiz, Gorkem; Eren, Tunc; Aydin-Ozemir, Zeynep; Alimoglu, Orhan

2016-11-01

Diabetes mellitus may cause degeneration in the myelin and/or axonal structures of peripheral nerves. The aim of this study was to investigate the effects of diabetic neuropathy on intraoperative neuromonitoring findings such as latency and amplitude values of the recurrent laryngeal nerves during thyroidectomy. To our knowledge this is the first study to report comparison of the electrophysiologic features of diabetic and non-diabetic patients. One-hundred-and-eleven consecutive patients who received neuromonitoring during thyroidectomy between 2013 and 2015 were included to study. The patients were divided into two groups according to the presence of diabetes mellitus. Pre-thyroidectomy and post thyroidectomy motor response latency and amplitude values of recurrent laryngeal nerves were compared between groups. Neuromonitoring findings, demographic data and postoperative complications were evaluated. The diabetic group consisted of 29 (26.1%) patients while 82 (73.9%) patients were in non-diabetic group. The mean post-thyroidectomy amplitude values (millivolts-mV) of the recurrent laryngeal nerve were significantly lower in diabetic group (0.51 ± 0.26 mV vs. 0,70 ± 0,46 mV, p < 0.05), whereas the latency values were significantly higher (2.50 ± 0.86 ms vs. 1.85 ± 0.59 ms, p < 0.01) compared to non-diabetic group. Additionally, post-thyroidectomy latency values were significantly increased compared to the pre-thyroidectomy latency values (2.50 ± 0.86 ms vs. 2.02 ± 0.43 ms) in diabetic group patients (p < 0.05). Although postoperative complication rates were higher in diabetic group (10.3% vs. 5.9%), there were no statistical significance differences. Prolonged latency and decreased amplitude values in recurrent laryngeal nerves of diabetic patients show that diabetic neuropathy of the recurrent laryngeal nerves develop similarly to the peripheral nerves. Increased post-thyroidectomy latency values reveal that the recurrent laryngeal

Neurophysiologic measures of auditory function in fish consumers: associations with long chain polyunsaturated fatty acids and methylmercury.

PubMed

Dziorny, Adam C; Orlando, Mark S; Strain, J J; Davidson, Philip W; Myers, Gary J

2013-09-01

Determining if associations exist between child neurodevelopment and environmental exposures, especially low level or background ones, is challenging and dependent upon being able to measure specific and sensitive endpoints. Psychometric or behavioral measures of CNS function have traditionally been used in such studies, but do have some limitations. Auditory neurophysiologic measures examine different nervous system structures and mechanisms, have fewer limitations, can more easily be quantified, and might be helpful additions to testing. To date, their use in human epidemiological studies has been limited. We reviewed the use of auditory brainstem responses (ABR) and otoacoustic emissions (OAE) in studies designed to determine the relationship of exposures to methyl mercury (MeHg) and nutrients from fish consumption with neurological development. We included studies of experimental animals and humans in an effort to better understand the possible benefits and risks of fish consumption. We reviewed the literature on the use of ABR and OAE to measure associations with environmental exposures that result from consuming a diet high in fish. We focused specifically on long chain polyunsaturated fatty acids (LCPUFA) and MeHg. We performed a comprehensive review of relevant studies using web-based search tools and appropriate search terms. Gestational exposure to both LCPUFA and MeHg has been reported to influence the developing auditory system. In experimental studies supplemental LCPUFA is reported to prolong ABR latencies and human studies also suggest an association. Experimental studies of acute and gestational MeHg exposure are reported to prolong ABR latencies and impair hair cell function. In humans, MeHg exposure is reported to prolong ABR latencies, but the impact on hair cell function is unknown. The auditory system can provide objective measures and may be useful in studying exposures to nutrients and toxicants and whether they are associated with children

Molecular control of HIV-1 postintegration latency: implications for the development of new therapeutic strategies

PubMed Central

2009-01-01

The persistence of HIV-1 latent reservoirs represents a major barrier to virus eradication in infected patients under HAART since interruption of the treatment inevitably leads to a rebound of plasma viremia. Latency establishes early after infection notably (but not only) in resting memory CD4+ T cells and involves numerous host and viral trans-acting proteins, as well as processes such as transcriptional interference, RNA silencing, epigenetic modifications and chromatin organization. In order to eliminate latent reservoirs, new strategies are envisaged and consist of reactivating HIV-1 transcription in latently-infected cells, while maintaining HAART in order to prevent de novo infection. The difficulty lies in the fact that a single residual latently-infected cell can in theory rekindle the infection. Here, we review our current understanding of the molecular mechanisms involved in the establishment and maintenance of HIV-1 latency and in the transcriptional reactivation from latency. We highlight the potential of new therapeutic strategies based on this understanding of latency. Combinations of various compounds used simultaneously allow for the targeting of transcriptional repression at multiple levels and can facilitate the escape from latency and the clearance of viral reservoirs. We describe the current advantages and limitations of immune T-cell activators, inducers of the NF-κB signaling pathway, and inhibitors of deacetylases and histone- and DNA- methyltransferases, used alone or in combinations. While a solution will not be achieved by tomorrow, the battle against HIV-1 latent reservoirs is well- underway. PMID:19961595

Oxaliplatin antagonizes HIV-1 latency by activating NF-κB without causing global T cell activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Xiaoli; Liu, Sijie; Wang, Pengfei

Highlights: • The chemotherapeutic drug oxaliplatin reactivates latent HIV-1 in this cell line model of HIV-1 latency. • Reactivation is synergized when oxaliplatin is used in combination with valproic acid. • Oxaliplatin reactivates latent HIV-1 through activation of NF-kB and does not induce T cell activation. - Abstract: Reactivation of latent HIV-1 is a promising strategy for the clearance of the viral reservoirs. Because of the limitations of current agents, identification of new latency activators is urgently required. Using an established model of HIV-1 latency, we examined the effect of Oxaliplatin on latent HIV-1 reactivation. We showed that Oxaliplatin, alonemore » or in combination with valproic acid (VPA), was able to reactivate HIV-1 without inducing global T cell activation. We also provided evidence that Oxaliplatin reactivated HIV-1 expression by inducing nuclear factor kappa B (NF-κB) nuclear translocation. Our results indicated that Oxaliplatin could be a potential drug candidate for anti-latency therapies.« less

Aging and wave-component latency delays in oVEMP and cVEMP: a systematic review with meta-analysis.

PubMed

Macambira, Ysa Karen Dos Santos; Carnaúba, Aline Tenório Lins; Fernandes, Luciana Castelo Branco Camurça; Bueno, Nassib Bezerra; Menezes, Pedro de Lemos

The natural aging process may result in morphological changes in the vestibular system and in the afferent neural pathway, including loss of hair cells, decreased numbers of vestibular nerve cells, and loss of neurons in the vestibular nucleus. Thus, with advancing age, there should be a decrease in amplitudes and an increase in latencies of the vestibular evoked myogenic potentials, especially the prolongation of p13 latency. Moreover, many investigations have found no significant differences in latencies with advancing age. To determine if there are significant differences in the latencies of cervical and ocular evoked myogenic potentials between elderly and adult patients. This is a systematic review with meta-analysis of observational studies, comparing the differences of these parameters between elderly and young adults, without language or date restrictions, in the following databases: Pubmed, ScienceDirect, SCOPUS, Web of Science, SciELO and LILACS, in addition to the gray literature databases: OpenGrey.eu and DissOnline, as well as Research Gate. The n1 oVEMP latencies had a mean delay in the elderly of 2.32ms with 95% CI of 0.55-4.10ms. The overall effect test showed p=0.01, disclosing that such difference was significant. The heterogeneity found was I 2 =96% (p<0.001). Evaluation of p1 latency was not possible due to the low number of articles selected for this condition. cVEMP analysis was performed in 13 articles. For the p13 component, the mean latency delay in the elderly was 1.34ms with 95% CI of 0.56-2.11ms. The overall effect test showed a p<0.001, with heterogeneity value I 2 =92% (p<0.001). For the n23 component, the mean latency delay for the elderly was 2.82ms with 95% CI of 0.33-5.30ms. The overall effect test showed p=0.03. The heterogeneity found was I 2 =99% (p<0.001). The latency of oVEMP n1 wave component and latencies of cVEMP p13 and n23 wave components are longer in the elderly aged >60 years than in young adults. Copyright © 2017

Identification of B Cells as a Major Site for Cyprinid Herpesvirus 3 Latency

PubMed Central

Reed, Aimee N.; Izume, Satoko; Dolan, Brian P.; LaPatra, Scott; Kent, Michael; Dong, Jing

2014-01-01

ABSTRACT Cyprinid herpesvirus 3 (CyHV-3), commonly known as koi herpesvirus (KHV), is a member of the Alloherpesviridae, and is a recently discovered emerging herpesvirus that is highly pathogenic for koi and common carp. Our previous study demonstrated that CyHV-3 becomes latent in peripheral white blood cells (WBC). In this study, CyHV-3 latency was further investigated in IgM+ WBC. The presence of the CyHV-3 genome in IgM+ WBC was about 20-fold greater than in IgM− WBC. To determine whether CyHV-3 expressed genes during latency, transcription from all eight open reading frames (ORFs) in the terminal repeat was investigated in IgM+ WBC from koi with latent CyHV-3 infection. Only a spliced ORF6 transcript was found to be abundantly expressed in IgM+ WBC from CyHV-3 latently infected koi. The spliced ORF6 transcript was also detected in vitro during productive infection as early as 1 day postinfection. The ORF6 transcript from in vitro infection begins at −127 bp upstream of the ATG codon and ends +188 bp downstream of the stop codon, +20 bp downstream of the polyadenylation signal. The hypothetical protein of ORF6 contains a consensus sequence with homology to a conserved domain of EBNA-3B and ICP4 from Epstein-Barr virus and herpes simplex virus 1, respectively, both members of the Herpesviridae. This is the first report of latent CyHV-3 in B cells and identification of gene transcription during latency for a member of the Alloherpesviridae. IMPORTANCE This is the first demonstration that a member of the Alloherpesviridae, cyprinid herpesvirus 3 (CyHV-3), establishes a latent infection in the B cells of its host, Cyprinus carpio. In addition, this is the first report of identification of gene transcription during latency for a member of Herpesvirales outside Herpesviridae. This is also the first report that the hypothetical protein of latent transcript of CyHV-3 contains a consensus sequence with homology to a conserved domain of EBNA-3B from Epstein

Identification of B cells as a major site for cyprinid herpesvirus 3 latency.

PubMed

Reed, Aimee N; Izume, Satoko; Dolan, Brian P; LaPatra, Scott; Kent, Michael; Dong, Jing; Jin, Ling

2014-08-01

Cyprinid herpesvirus 3 (CyHV-3), commonly known as koi herpesvirus (KHV), is a member of the Alloherpesviridae, and is a recently discovered emerging herpesvirus that is highly pathogenic for koi and common carp. Our previous study demonstrated that CyHV-3 becomes latent in peripheral white blood cells (WBC). In this study, CyHV-3 latency was further investigated in IgM(+) WBC. The presence of the CyHV-3 genome in IgM(+) WBC was about 20-fold greater than in IgM(-) WBC. To determine whether CyHV-3 expressed genes during latency, transcription from all eight open reading frames (ORFs) in the terminal repeat was investigated in IgM(+) WBC from koi with latent CyHV-3 infection. Only a spliced ORF6 transcript was found to be abundantly expressed in IgM(+) WBC from CyHV-3 latently infected koi. The spliced ORF6 transcript was also detected in vitro during productive infection as early as 1 day postinfection. The ORF6 transcript from in vitro infection begins at -127 bp upstream of the ATG codon and ends +188 bp downstream of the stop codon, +20 bp downstream of the polyadenylation signal. The hypothetical protein of ORF6 contains a consensus sequence with homology to a conserved domain of EBNA-3B and ICP4 from Epstein-Barr virus and herpes simplex virus 1, respectively, both members of the Herpesviridae. This is the first report of latent CyHV-3 in B cells and identification of gene transcription during latency for a member of the Alloherpesviridae. This is the first demonstration that a member of the Alloherpesviridae, cyprinid herpesvirus 3 (CyHV-3), establishes a latent infection in the B cells of its host, Cyprinus carpio. In addition, this is the first report of identification of gene transcription during latency for a member of Herpesvirales outside Herpesviridae. This is also the first report that the hypothetical protein of latent transcript of CyHV-3 contains a consensus sequence with homology to a conserved domain of EBNA-3B from Epstein-Barr virus and ICP4

Postural response latencies are related to balance control during standing and walking in patients with multiple sclerosis

PubMed Central

Huisinga, Jessie M.; St. George, Rebecca J.; Spain, Rebecca; Overs, Shannon; Horak, Fay B.

2015-01-01

Objective To understand examined the relationship between postural response latencies obtained during postural perturbations and representative measures of balance during standing (sway variables) and during walking (trunk motion). Design Cross-sectional Setting University medical center balance disorders laboratory Participants Forty persons with MS were compared with 20 similar aged control subjects. Twenty subjects with MS had normal walking velocity group and 20 had slow walking velocity based on the 25-foot walk time greater than 5 seconds. Interventions None Main Outcome Measures Postural response latency, sway variables, trunk motion variables Results: We found that subjects with MS with either slow or normal walking velocities had significantly longer postural response latencies than the healthy control group. Postural response latency was not correlated with the 25-ft walk time. Postural response latency was significantly correlated with center of pressure sway variables during quiet standing: root mean square (ρ = 0.334, p=0.040), range (ρ=0.385, p=0.017), mean velocity (ρ=0.337, p=0.038), and total sway area (ρ=0.393, p=0.015). Postural response latency was also significantly correlated with motion of the trunk during walking: sagittal plane range of motion (ρ=0.316, p=0.050) and standard deviation of transverse plane range of motion (ρ=-0.430, p=0.006). Conclusions These findings clearly indicate that slow postural responses to external perturbations in patients with MS contribute to disturbances in balance control, both during standing and walking. PMID:24445088

[Prediction of the latency period by cervical ultrasonography in premature rupture of the membranes before term].

PubMed

Gabriel, R; Morille, C; Drieux, L; Bige, V; Leymarie, F; Quereux, C

2002-11-01

To assess the value of ultrasonographic measurement of cervical length for predicting the duration of the latency period from admission to delivery in women with preterm premature rupture of the membranes (PROM). Prospective study in 88 women with preterm PROM before 34 weeks of amenorrhea. The median gestational age at admission was of 30.1 weeks. The clinical management included: no digital examination of the uterine cervix, antenatal corticosteroids, antibiotics (amoxicillin & clavulanic acid) for 7 days, and hoding back until 34 weeks. Cervical length at admission was determined with transvaginal ultrasonography. The duration of the latency period was studied in relation with cervical length, serum C-reactive protein (CRP) level and white blood cell (WBC) count at admission. The median latency period was longer in women with a cervical length > or = 25 mm (10 vs 5 days; p = 0.04), but this was not associated with a significant increase in birth weight. The median latency period was also longer in women with CRP < 20 mg/l (10 vs 3 days; p < 0.001) and this was associated with a significant increase in birth weight (1716 +/- 549 vs 1201 +/- 485 g; p < 0.01). Moreover, increased CRP levels were more frequent in women with a cervical length < 25 mm, and cervical length was no more predictive of the duration of the latency period in the subgroup of women with CRP < 20 mg/l and WBC < 20,000 cells/mm3. In women with preterm PROM, the latency period from admission to delivery is shorter when cervical length is < 25 mm. However, the clinical value of transvaginal ultrasonography is limited in comparison with serum CRP.

A hundred years of latency: from Freudian psychosexual theory to dynamic systems nonlinear development in middle childhood.

PubMed

Knight, Rona

2014-04-01

A focus on the latency phase is used to illustrate how theory and developmental research have influenced our psychoanalytic views of development over the past hundred years. Beginning with Freud's psychosexual theory and his conception of latency, an historical overview of the major psychoanalytic contributions bearing on this developmental period over the past century is presented. Recent longitudinal research in latency supports a nonlinear dynamic systems approach to development. This approach obliges us to reconsider our linear theories and how we think about and work with our patients.

Quantifying risk over the life course - latency, age-related susceptibility, and other time-varying exposure metrics.

PubMed

Wang, Molin; Liao, Xiaomei; Laden, Francine; Spiegelman, Donna

2016-06-15

Identification of the latency period and age-related susceptibility, if any, is an important aspect of assessing risks of environmental, nutritional, and occupational exposures. We consider estimation and inference for latency and age-related susceptibility in relative risk and excess risk models. We focus on likelihood-based methods for point and interval estimation of the latency period and age-related windows of susceptibility coupled with several commonly considered exposure metrics. The method is illustrated in a study of the timing of the effects of constituents of air pollution on mortality in the Nurses' Health Study. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Coexistence of enhanced mobile broadband communications and ultra-reliable low-latency communications in mobile front-haul

NASA Astrophysics Data System (ADS)

Ying, Kai; Kowalski, John M.; Nogami, Toshizo; Yin, Zhanping; Sheng, Jia

2018-01-01

5G systems are supposed to support coexistence of multiple services such as ultra reliable low latency communications (URLLC) and enhanced mobile broadband (eMBB) communications. The target of eMBB communications is to meet the high-throughput requirement while URLLC are used for some high priority services. Due to the sporadic nature and low latency requirement, URLLC transmission may pre-empt the resource of eMBB transmission. Our work is to analyze the URLLC impact on eMBB transmission in mobile front-haul. Then, some solutions are proposed to guarantee the reliability/latency requirements for URLLC services and minimize the impact to eMBB services at the same time.

Epstein-Barr virus latency switch in human B-cells: a physico-chemical model.

PubMed

Werner, Maria; Ernberg, Ingemar; Zou, Jiezhi; Almqvist, Jenny; Aurell, Erik

2007-08-31

The Epstein-Barr virus is widespread in all human populations and is strongly associated with human disease, ranging from infectious mononucleosis to cancer. In infected cells the virus can adopt several different latency programs, affecting the cells' behaviour. Experimental results indicate that a specific genetic switch between viral latency programs, reprograms human B-cells between proliferative and resting states. Each of these two latency programs makes use of a different viral promoter, Cp and Qp, respectively. The hypothesis tested in this study is that this genetic switch is controlled by both human and viral transcription factors; Oct-2 and EBNA-1. We build a physico-chemical model to investigate quantitatively the dynamical properties of the promoter regulation and experimentally examine protein level variations between the two latency programs. Our experimental results display significant differences in EBNA-1 and Oct-2 levels between resting and proliferating programs. With the model we identify two stable latency programs, corresponding to a resting and proliferating cell. The two programs differ in robustness and transcriptional activity. The proliferating state is markedly more stable, with a very high transcriptional activity from its viral promoter. We predict the promoter activities to be mutually exclusive in the two different programs, and our relative promoter activities correlate well with experimental data. Transitions between programs can be induced, by affecting the protein levels of our transcription factors. Simulated time scales are in line with experimental results. We show that fundamental properties of the Epstein-Barr virus involvement in latent infection, with implications for tumor biology, can be modelled and understood mathematically. We conclude that EBNA-1 and Oct-2 regulation of Cp and Qp is sufficient to establish mutually exclusive expression patterns. Moreover, the modelled genetic control predict both mono- and bistable

Characterization of herpes simplex virus type 2 latency-associated transcription in human sacral ganglia and in cell culture.

PubMed

Croen, K D; Ostrove, J M; Dragovic, L; Straus, S E

1991-01-01

The ability of herpes simplex virus type 2 (HSV-2) to establish latency in and reactivate from sacral dorsal root sensory ganglia is the basis for recurrent genital herpes. The expression of HSV-2 genes in latently infected human sacral ganglia was investigated by in situ hybridization. Hybridizations with a probe from the long repeat region of HSV-2 revealed strong nuclear signals overlying neurons in sacral ganglia from five of nine individuals. The RNA detected overlaps with the transcript for infected cell protein O but in the opposite, or "anti-sense," orientation. These observations mimic those made previously with HSV-1 in human trigeminal ganglia and confirm the recent findings during latency in HSV-2-infected mice and guinea pigs. Northern hybridization of RNA from infected Vero cells showed that an HSV-2 latency-associated transcript was similar in size to the larger (1.85 kb) latency transcript of HSV-1. Thus, HSV-1 and HSV-2 latency in human sensory ganglia are similar, if not identical, in terms of their cellular localization and pattern of transcription.

Prolongation of latencies for passive avoidance responses in rats treated with aniracetam or piracetam.

PubMed

Yamada, K; Inoue, T; Tanaka, M; Furukawa, T

1985-04-01

Effects of aniracetam (1-anysoyl-2-pyrrolodone) and piracetam (1-acetamido-2-pyrrolidone) on passive avoidance behavior were studied in 2 and 18 months old rats using a step-down passive avoidance task. Repeated administration of aniracetam (30 and 50 mg/kg, IP X 5 days) or piracetam (100 mg/kg, IP X 5 days) significantly prolonged step-down latencies for a passive avoidance task in 2 months old rats. Administration of aniracetam (50 mg/kg, IP) or piracetam (100 mg/kg, IP), however, did not affect locomotor activity. This prolongation of latencies was also seen with oral administration of aniracetam (50 mg/kg X 5 days). Similar prolongation of latencies also occurred in 18 months old rat treated with aniracetam (50 mg/kg, IP X 5 days). The results imply that aniracetam may improve learning and/or memory in 2 and 18 months old rats.

Increasing Latency Age Children's Sensitivity to Racial and Ethnic Differences through Enhancing their Awareness and Knowledge.

ERIC Educational Resources Information Center

Lewis, Alvin D.

This practicum addressed the needs of latency age children who were insensitive to racial and ethnic differences. These needs were met by designing and developing a Cultural Awareness Program, so as to increase latency age children's sensitivity to racial and ethnic differences. The program's focus was on helping the children gain an appreciation…

Tap Arduino: An Arduino microcontroller for low-latency auditory feedback in sensorimotor synchronization experiments.

PubMed

Schultz, Benjamin G; van Vugt, Floris T

2016-12-01

Timing abilities are often measured by having participants tap their finger along with a metronome and presenting tap-triggered auditory feedback. These experiments predominantly use electronic percussion pads combined with software (e.g., FTAP or Max/MSP) that records responses and delivers auditory feedback. However, these setups involve unknown latencies between tap onset and auditory feedback and can sometimes miss responses or record multiple, superfluous responses for a single tap. These issues may distort measurements of tapping performance or affect the performance of the individual. We present an alternative setup using an Arduino microcontroller that addresses these issues and delivers low-latency auditory feedback. We validated our setup by having participants (N = 6) tap on a force-sensitive resistor pad connected to the Arduino and on an electronic percussion pad with various levels of force and tempi. The Arduino delivered auditory feedback through a pulse-width modulation (PWM) pin connected to a headphone jack or a wave shield component. The Arduino's PWM (M = 0.6 ms, SD = 0.3) and wave shield (M = 2.6 ms, SD = 0.3) demonstrated significantly lower auditory feedback latencies than the percussion pad (M = 9.1 ms, SD = 2.0), FTAP (M = 14.6 ms, SD = 2.8), and Max/MSP (M = 15.8 ms, SD = 3.4). The PWM and wave shield latencies were also significantly less variable than those from FTAP and Max/MSP. The Arduino missed significantly fewer taps, and recorded fewer superfluous responses, than the percussion pad. The Arduino captured all responses, whereas at lower tapping forces, the percussion pad missed more taps. Regardless of tapping force, the Arduino outperformed the percussion pad. Overall, the Arduino is a high-precision, low-latency, portable, and affordable tool for auditory experiments.

The sequence of cortical activity inferred by response latency variability in the human ventral pathway of face processing.

PubMed

Lin, Jo-Fu Lotus; Silva-Pereyra, Juan; Chou, Chih-Che; Lin, Fa-Hsuan

2018-04-11

Variability in neuronal response latency has been typically considered caused by random noise. Previous studies of single cells and large neuronal populations have shown that the temporal variability tends to increase along the visual pathway. Inspired by these previous studies, we hypothesized that functional areas at later stages in the visual pathway of face processing would have larger variability in the response latency. To test this hypothesis, we used magnetoencephalographic data collected when subjects were presented with images of human faces. Faces are known to elicit a sequence of activity from the primary visual cortex to the fusiform gyrus. Our results revealed that the fusiform gyrus showed larger variability in the response latency compared to the calcarine fissure. Dynamic and spectral analyses of the latency variability indicated that the response latency in the fusiform gyrus was more variable than in the calcarine fissure between 70 ms and 200 ms after the stimulus onset and between 4 Hz and 40 Hz, respectively. The sequential processing of face information from the calcarine sulcus to the fusiform sulcus was more reliably detected based on sizes of the response variability than instants of the maximal response peaks. With two areas in the ventral visual pathway, we show that the variability in response latency across brain areas can be used to infer the sequence of cortical activity.

Outcomes of a NASA Workshop to Develop a Portfolio of Low Latency Datasets for Time-Sensitive Applications

NASA Technical Reports Server (NTRS)

Davies, Diane K.; Brown, Molly E.; Green, David S.; Michael, Karen A.; Murray, John J.; Justice, Christopher O.; Soja, Amber J.

2016-01-01

It is widely accepted that time-sensitive remote sensing data serve the needs of decision makers in the applications communities and yet to date, a comprehensive portfolio of NASA low latency datasets has not been available. This paper will describe the NASA low latency, or Near-Real Time (NRT), portfolio, how it was developed and plans to make it available online through a portal that leverages the existing EOSDIS capabilities such as the Earthdata Search Client (https:search.earthdata.nasa.gov), the Common Metadata Repository (CMR) and the Global Imagery Browse Service (GIBS). This paper will report on the outcomes of a NASA Workshop to Develop a Portfolio of Low Latency Datasets for Time-Sensitive Applications (27-29 September 2016 at NASA Langley Research Center, Hampton VA). The paper will also summarize findings and recommendations from the meeting outlining perceived shortfalls and opportunities for low latency research and application science.

[Origin of acoustically evoked short latency negative response in guinea pigs].

PubMed

Huang, Wen-qin; Qin, Huan-hua; Nong, Dong-xiao; Tang, An-zhou; Li, Zhi-mei; Yang, Tian

2011-04-01

To establish a model of acoustically evoked short latency negative response (ASNR) in guinea pigs, a model of profound hearing loss with normal saccular functions, and verify the correlation between ASNR and vestibular evoked myogenic potential (VEMP). Thirty-two healthy guinea pigs were employed in the experiment, which were randomly divided into control group (16 subjects) and deafened group (16 subjects). Each animal experienced auditory and vestibular tests including auditory brainstem response (ABR), VEMP and caloric test. A quick treatment was employed for deafened group consisting of a subcutaneous injection of kanamycin at a dose of 400 mg/kg followed by a jugular vein injection of ethacrynic acid at a dose of 40 mg/kg one hour later. The animals were received ABR, VEMP and caloric test 7 - 10 days following the drug administration. The deafened group was further divided into ASNR group and non-ASNR group, based on the presence of ASNR. In deafened group, five subjects died postoperatively, 11 subjects (22 ears) provided full data, ASNR was elicited in eight ears (36.4%), the threshold was 120 - 130 dB SPL with mean of (124.4 ± 4.96) dB SPL. Its latency range was 1.75 - 2.60 ms with mean of (2.15 ± 0.27) ms. The mean latency of threshold was (2.34 ± 0.18) ms. All eight ASNR ears presented with VEMP. The VEMP threshold, positive and negative potential latencies proved no statistical difference (P > 0.05) between ASNR group and control group. Significant difference was detected between the VEMP presence of ASNR group and non-ASNR group (P = 0.002). There was no statistically significant correlation between VEMP and caloric test neither between ASNR and caloric test in deafened group. This study evoked ASNR in an ototoxicity guinea pig model which has profound hearing loss with normal saccular functions. The presence of ASNR correlated with VEMP, however, not correlated with caloric test, suggesting that ASNR and VEMP are both originated from the saccule.

Mars Surface Operations via Low-Latency Telerobotics from Phobos

NASA Technical Reports Server (NTRS)

Wright, Michael; Lupisella, Mark

2016-01-01

To help assess the feasibility and timing of Low-Latency Telerobotics (LLT) operations on Mars via a Phobos telecommand base, operations concepts (ops cons) and timelines for several representative sequences for Mars surface operations have been developed. A summary of these LLT sequences and timelines will be presented, along with associated assumptions, operational considerations, and challenges.

Rabbit and Mouse Models of HSV-1 Latency, Reactivation, and Recurrent Eye Diseases

PubMed Central

Webre, Jody M.; Hill, James M.; Nolan, Nicole M.; Clement, Christian; McFerrin, Harris E.; Bhattacharjee, Partha S.; Hsia, Victor; Neumann, Donna M.; Foster, Timothy P.; Lukiw, Walter J.; Thompson, Hilary W.

2012-01-01

The exact mechanisms of HSV-1 establishment, maintenance, latency, reactivation, and also the courses of recurrent ocular infections remain a mystery. Comprehensive understanding of the HSV-1 disease process could lead to prevention of HSV-1 acute infection, reactivation, and more effective treatments of recurrent ocular disease. Animal models have been used for over sixty years to investigate our concepts and hypotheses of HSV-1 diseases. In this paper we present descriptions and examples of rabbit and mouse eye models of HSV-1 latency, reactivation, and recurrent diseases. We summarize studies in animal models of spontaneous and induced HSV-1 reactivation and recurrent disease. Numerous stimuli that induce reactivation in mice and rabbits are described, as well as factors that inhibit viral reactivation from latency. The key features, advantages, and disadvantages of the mouse and rabbit models in relation to the study of ocular HSV-1 are discussed. This paper is pertinent but not intended to be all inclusive. We will give examples of key papers that have reported novel discoveries related to the review topics. PMID:23091352

Assessment of rock musician's efferent system functioning using contralateral suppression of otoacoustic emissions.

PubMed

Kumar, Prawin; Grover, Vibhu; Publius A, Sam; Sanju, Himanshu Kumar; Sinha, Sachchidanand

2016-12-01

Contralateral suppression of oto acoustic emission (OAE) is referred as activation of efferent system. Previous literature mentioned about the importance of contralateral suppression of OAEs as a tool to assess efferent system in different groups of population. There is dearth of literature to explore the efferent system function in experienced musicians exposed to rock music using TEOAEs and DPOAEs. Two groups of participant (14 rock musicians and 14 non-musicians) in the age range of 18-25 years were involved in the study. Contralateral suppression of TEOAEs and DPOAEs were measured using ILO (Version 6) in both groups. Descriptive statistics showed higher suppression of TEOAEs and DPOAEs in rock-musicians at most of the frequencies in comparison to non-musicians. For DPOAE measures, Mann Whitney U test results revealed significantly greater DPOAE suppression only at 1 kHz and 3 kHz in rock-musicians compared to non-musicians. For within group comparison, Kruskal Wallis test results revealed there were significant difference observed across most of the frequencies i.e. at 1 kHz, 3 kHz and 6 kHz. For TEOAE measures, Mann Whitney U test results revealed that only at 2 kHz, TEOAE suppression in rock-musician was significantly greater compared to non-musicians. Similarly, Kuskal Wallis test results revealed that within group there were no significant differences observed for most of the frequencies except 2 kHz. Based on the above finding, present study concludes that rock musicians are having better efferent system compared to non-musicians. No suppression effect at few frequencies probably indicates more vulnerability at those frequencies. Contralateral suppression of DPOAE shows more significant finding in comparison to contralateral suppression of TEOAEs in present study.

Quantifying Risk Over the Life Course – Latency, Age-Related Susceptibility, and Other Time-Varying Exposure Metrics

PubMed Central

Wang, Molin; Liao, Xiaomei; Laden, Francine; Spiegelman, Donna

2016-01-01

Identification of the latency period and age-related susceptibility, if any, is an important aspect of assessing risks of environmental, nutritional and occupational exposures. We consider estimation and inference for latency and age-related susceptibility in relative risk and excess risk models. We focus on likelihood-based methods for point and interval estimation of the latency period and age-related windows of susceptibility coupled with several commonly considered exposure metrics. The method is illustrated in a study of the timing of the effects of constituents of air pollution on mortality in the Nurses’ Health Study. PMID:26750582

The influence of target angular velocity on visual latency difference determined using the rotating Pulfrich effect.

PubMed

Nickalls, R W

1996-09-01

Visual latency difference was determined directly in normal volunteers, using the rotating Pulfrich technique described by Nickalls [Vision Research, 26, 367-372 (1986)]. Subjects fixated a black vertical rod rotating clockwise on a horizontal turntable turning with constant angular velocity (16.6,33.3 or 44.7 revs/min) with a neutral density filter (OD 0.7 or 1.5) in front of the right eye. For all subjects the latency difference associated with the 1.5 OD filter was significantly greater (P < 0.001) with the rod rotating at 16.6 rev/min than at 33.3 revs/min. The existence of an inverse relationship between latency difference and angular velocity is hypothesized.

[Latency problems with smothering using soft cover].

PubMed

Wirth, Ingo; Strauch, Hansjürg; Schmeling, Andreas

2007-01-01

Smothering by covering the respiratory orifices with soft material is one of the rarely established forms of mechanically induced death by asphyxia. An important reason of latency is that this kind of homicide leaves almost no traces. The two described cases from the autopsy material of the Institute of Legal Medicine in Berlin (CCM) show the limits of medico-legal interpretation and the resulting special responsibility of the investigator. In the first case the defendant denied the offence and was acquitted of the charge, while in the second case the self-confessed offender was convicted.

Latency-Efficient Communication in Wireless Mesh Networks under Consideration of Large Interference Range

NASA Astrophysics Data System (ADS)

Xin, Qin; Yao, Xiaolan; Engelstad, Paal E.

2010-09-01

Wireless Mesh Networking is an emerging communication paradigm to enable resilient, cost-efficient and reliable services for the future-generation wireless networks. We study here the minimum-latency communication primitive of gossiping (all-to-all communication) in multi-hop ad-hoc Wireless Mesh Networks (WMNs). Each mesh node in the WMN is initially given a message and the objective is to design a minimum-latency schedule such that each mesh node distributes its message to all other mesh nodes. Minimum-latency gossiping problem is well known to be NP-hard even for the scenario in which the topology of the WMN is known to all mesh nodes in advance. In this paper, we propose a new latency-efficient approximation scheme that can accomplish gossiping task in polynomial time units in any ad-hoc WMN under consideration of Large Interference Range (LIR), e.g., the interference range is much larger than the transmission range. To the best of our knowledge, it is first time to investigate such a scenario in ad-hoc WMNs under LIR, our algorithm allows the labels (e.g., identifiers) of the mesh nodes to be polynomially large in terms of the size of the WMN, which is the first time that the scenario of large labels has been considered in ad-hoc WMNs under LIR. Furthermore, our gossiping scheme can be considered as a framework which can be easily implied to the scenario under consideration of mobility-related issues since we assume that the mesh nodes have no knowledge on the network topology even for its neighboring mesh nodes.

Use of a latency-based demand assessment to identify potential demands for functional analyses.

PubMed

Call, Nathan A; Miller, Sarah J; Mintz, Joslyn Cynkus; Mevers, Joanna Lomas; Scheithauer, Mindy C; Eshelman, Julie E; Beavers, Gracie A

2016-12-01

Unlike potential tangible positive reinforcers, which are typically identified for inclusion in functional analyses empirically using preference assessments, demands are most often selected arbitrarily or based on caregiver report. The present study evaluated the use of a demand assessment with 12 participants who exhibited escape-maintained problem behavior. Participants were exposed to 10 demands, with aversiveness measured by average latency to the first instance of problem behavior. In subsequent functional analyses, results of a demand condition that included the demand with the shortest latency to problem behavior resulted in identification of an escape function for 11 of the participants. In contrast, a demand condition that included the demand with the longest latency resulted in identification of an escape function for only 5 participants. The implication of these findings is that for the remaining 7 participants, selection of the demand for the functional analysis without using the results of the demand assessment could have produced a false-negative finding. © 2016 Society for the Experimental Analysis of Behavior.

Auditory brainstem response latency in forward masking, a marker of sensory deficits in listeners with normal hearing thresholds

PubMed Central

Mehraei, Golbarg; Gallardo, Andreu Paredes; Shinn-Cunningham, Barbara G.; Dau, Torsten

2017-01-01

In rodent models, acoustic exposure too modest to elevate hearing thresholds can nonetheless cause auditory nerve fiber deafferentation, interfering with the coding of supra-threshold sound. Low-spontaneous rate nerve fibers, important for encoding acoustic information at supra-threshold levels and in noise, are more susceptible to degeneration than high-spontaneous rate fibers. The change in auditory brainstem response (ABR) wave-V latency with noise level has been shown to be associated with auditory nerve deafferentation. Here, we measured ABR in a forward masking paradigm and evaluated wave-V latency changes with increasing masker-to-probe intervals. In the same listeners, behavioral forward masking detection thresholds were measured. We hypothesized that 1) auditory nerve fiber deafferentation increases forward masking thresholds and increases wave-V latency and 2) a preferential loss of low-SR fibers results in a faster recovery of wave-V latency as the slow contribution of these fibers is reduced. Results showed that in young audiometrically normal listeners, a larger change in wave-V latency with increasing masker-to-probe interval was related to a greater effect of a preceding masker behaviorally. Further, the amount of wave-V latency change with masker-to-probe interval was positively correlated with the rate of change in forward masking detection thresholds. Although we cannot rule out central contributions, these findings are consistent with the hypothesis that auditory nerve fiber deafferentation occurs in humans and may predict how well individuals can hear in noisy environments. PMID:28159652

In vitro effects of the small-molecule protein kinase C agonists on HIV latency reactivation.

PubMed

Brogdon, Jessica; Ziani, Widade; Wang, Xiaolei; Veazey, Ronald S; Xu, Huanbin

2016-12-12

The persistence of latently HIV-infected cellular reservoirs represents the major obstacle to virus eradication in patients under antiretroviral therapy (ART). Cure strategies to eliminate these reservoirs are thus needed to reactivate proviral gene expression in latently infected cells. In this study, we tested optimal concentrations of PKC agonist candidates (PEP005/Ingenol-3-angelate, prostratin, bryostatin-1, and JQ1) to reactivate HIV latency in vitro, and examined their effects on cell survival, activation and epigenetic histone methylation after treatment alone or in combination in cell line and isolated CD4 T cells from SIV-infected macaques. The results showed that PKC agonists increased cell activation with different degrees of latency reactivation, concomitant with reduced levels of histone methylation. With increasing concentrations, prostratin and byrostain-1 treatment rapidly reduced cell survival and cell activation. The PKC agonist combinations, or in combination with JQ1, led to modest levels of synergistic reactivation of HIV. Remarkably, PEP005 treatment alone caused marked reactivation of HIV latency, similar to PMA stimulation. These findings suggested that PEP005 alone, as indicated its lower cytotoxicity and lower effective dose inducing maximal reactivation, might be a candidate for effectively reactivating HIV latency as part of a therapeutic strategy for HIV infection.

Shrapnel: Latency, Mourning and the Suicide of a Parent

ERIC Educational Resources Information Center

Bisagni, Francesco

2012-01-01

The aim of this paper is to describe some acute responses to the suicide of a parent, through the account of the analytic psychotherapy of a latency child who found the body of his dead father. The acute traumatic responses of the child show that the perceptual apparatus, time and space are subverted, while the functioning of the contact barrier…

Matching Pursuit with Asymmetric Functions for Signal Decomposition and Parameterization

PubMed Central

Spustek, Tomasz; Jedrzejczak, Wiesław Wiktor; Blinowska, Katarzyna Joanna

2015-01-01

The method of adaptive approximations by Matching Pursuit makes it possible to decompose signals into basic components (called atoms). The approach relies on fitting, in an iterative way, functions from a large predefined set (called dictionary) to an analyzed signal. Usually, symmetric functions coming from the Gabor family (sine modulated Gaussian) are used. However Gabor functions may not be optimal in describing waveforms present in physiological and medical signals. Many biomedical signals contain asymmetric components, usually with a steep rise and slower decay. For the decomposition of this kind of signal we introduce a dictionary of functions of various degrees of asymmetry – from symmetric Gabor atoms to highly asymmetric waveforms. The application of this enriched dictionary to Otoacoustic Emissions and Steady-State Visually Evoked Potentials demonstrated the advantages of the proposed method. The approach provides more sparse representation, allows for correct determination of the latencies of the components and removes the "energy leakage" effect generated by symmetric waveforms that do not sufficiently match the structures of the analyzed signal. Additionally, we introduced a time-frequency-amplitude distribution that is more adequate for representation of asymmetric atoms than the conventional time-frequency-energy distribution. PMID:26115480

Involvement of histone methyltransferase GLP in HIV-1 latency through catalysis of H3K9 dimethylation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Donglin; Qu, Xiying; Li, Lin

Understanding the mechanism of HIV-1 latency is crucial to eradication of the viral reservoir in HIV-1-infected individuals. However, the role of histone methyltransferase (HMT) G9a-like protein (GLP) in HIV-1 latency is still unclear. In the present work, we established four clonal cell lines containing HIV-1 vector. We found that the integration sites of most clonal cell lines favored active gene regions. However, we also observed hypomethylation of CpG of HIV 5′LTR in all four clonal cell lines. Additionally, 5′-deoxy-5′-methylthioadenosine (MTA), a broad-spectrum histone methyltransferase inhibitor, was used to examine the role of histone methylation in HIV-1 latency. MTA was foundmore » to decrease the level of H3K9 dimethylation, causing reactivation of latent HIV-1 in C11 cells. GLP knockdown by small interfering RNA clearly induced HIV-1 LTR expression. Results suggest that GLP may play a significant role in the maintenance of HIV-1 latency by catalyzing dimethylation of H3K9. - Highlights: ► We have established an in vitro model of HIV-1 latency. ► The integration sites of most clonal cell lines favor in active gene regions. ► Hypomethylation occurs in CpG islands of HIV 5′LTR in all four clonal cell lines. ► MTA can reactivate latent HIV-1 by decreasing the level of H3K9 me2 in C11 cells. ► HMT GLP may play a significant role in the maintenance of HIV-1 latency.« less

Sensor Spatial Distortion, Visual Latency, and Update Rate Effects on 3D Tracking in Virtual Environments

NASA Technical Reports Server (NTRS)

Ellis, S. R.; Adelstein, B. D.; Baumeler, S.; Jense, G. J.; Jacoby, R. H.; Trejo, Leonard (Technical Monitor)

1998-01-01

Several common defects that we have sought to minimize in immersing virtual environments are: static sensor spatial distortion, visual latency, and low update rates. Human performance within our environments during large amplitude 3D tracking was assessed by objective and subjective methods in the presence and absence of these defects. Results show that 1) removal of our relatively small spatial sensor distortion had minor effects on the tracking activity, 2) an Adapted Cooper-Harper controllability scale proved the most sensitive subjective indicator of the degradation of dynamic fidelity caused by increasing latency and decreasing frame rates, and 3) performance, as measured by normalized RMS tracking error or subjective impressions, was more markedly influenced by changing visual latency than by update rate.

Auditory pathway maturational study in small for gestational age preterm infants.

PubMed

Angrisani, Rosanna Giaffredo; Diniz, Edna Maria Albuquerque; Guinsburg, Ruth; Ferraro, Alexandre Archanjo; Azevedo, Marisa Frasson de; Matas, Carla Gentile

2014-01-01

To follow up the maturation of the auditory pathway in preterm infants small for gestational age (SGA), through the study of absolute and interpeak latencies of auditory brainstem response (ABR) in the first six months of age. This multicentric prospective cross-sectional and longitudinal study assessed 76 newborn infants, 35 SGA and 41 appropriate for gestational age (AGA), born between 33 and 36 weeks in the first evaluation. The ABR was carried out in three moments (neonatal period, three months and six months). Twenty-nine SGA and 33 AGA (62 infants), between 51 and 54 weeks (corrected age), returned for the second evaluation. In the third evaluation, 49 infants (23 SGA and 26 AGA), with age range from 63 to 65 weeks (corrected age), were assessed. The bilateral presence of Transient Evoked Otoacoustic Emissions and normal tympanogram were inclusion criteria. It was found interaural symmetry in both groups. The comparison between the two groups throughout the three periods studied showed no significant differences in the ABR parameters, except for the latencies of wave III in the period between three and six months. As for the maturation with tone burst 0.5 and 1 kHz, it was found that the groups did not differ. The findings suggest that, in the premature infants, the maturational process of the auditory pathway occurs in a similar rate for SGA and AGA. These results also suggest that prematurity is a more relevant factor for the maturation of the auditory pathway than birth weight.

Increased latencies to respond in a judgment bias test are not associated with pessimistic biases in rats.

PubMed

Barker, Timothy Hugh; Howarth, Gordon Stanley; Whittaker, Alexandra Louise

2018-01-01

Extinction of learning is a common, yet under-reported limitation of judgment bias testing methods Repeated exposure to the ambiguous probe of a judgment bias paradigm encourages the animal to cease display of the required behaviours. However, there remains a need to repeatedly test animals to achieve statistical power. A delicate balance therefore needs to be struck between over- and under-exposure of the animals to the test conditions. This study presents the data of rats, a common animal subject of judgment bias testing. Rats were exposed to the ambiguous probe of a common, active-choice judgment bias test for 11 consecutive days. There was a significant increase in the latency to respond to the ambiguous probe following day 8, with no significant increase experienced for either the positive or less-positive probes. Following day 8 there was a significant increase in both optimistic and pessimistic latencies in response to the ambiguous probe. Therefore, repeated exposure to the ambiguous probe caused an increased latency in response even though optimistic interpretations were recorded. This implies that the use of response latency alone as a measure in judgment bias testing can falsely identify pessimism. Researchers should modify experimental design to include both choice and latency measures. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

The Relationship between Parameters of Long-Latency Evoked Potentials in a Multisensory Design.

PubMed

Hernández, Oscar H; García-Martínez, Rolando; Monteón, Victor

2016-10-01

In previous papers, we have shown that parameters of the omitted stimulus potential (OSP), which occurs at the end of a train of sensory stimuli, strongly depend on the modality. A train of stimuli also produces long-latency evoked potentials (LLEP) at the beginning of the train. This study is an extension of the OSP research, and it tested the relationship between parameters (ie, rate of rise, amplitude, and peak latency) of the P2 waves when trains of auditory, visual, or somatosensory stimuli were applied. The dynamics of the first 3 potentials in the train, related to habituation, were also studied. Twenty healthy young college volunteers participated in the study. As in the OSP, the P2 was faster and higher for auditory than for visual or somatosensory stimuli. The first P2 was swifter and higher than the second and the third potentials. The strength of habituation depends on the sensory modality and the parameter used. All these findings support the view that many long-latency brain potentials could share neural mechanisms related to wave generation. © EEG and Clinical Neuroscience Society (ECNS) 2015.

A comparison of herpes simplex virus type 1 and varicella-zoster virus latency and reactivation.

PubMed

Kennedy, Peter G E; Rovnak, Joel; Badani, Hussain; Cohrs, Randall J

2015-07-01

Herpes simplex virus type 1 (HSV-1; human herpesvirus 1) and varicella-zoster virus (VZV; human herpesvirus 3) are human neurotropic alphaherpesviruses that cause lifelong infections in ganglia. Following primary infection and establishment of latency, HSV-1 reactivation typically results in herpes labialis (cold sores), but can occur frequently elsewhere on the body at the site of primary infection (e.g. whitlow), particularly at the genitals. Rarely, HSV-1 reactivation can cause encephalitis; however, a third of the cases of HSV-1 encephalitis are associated with HSV-1 primary infection. Primary VZV infection causes varicella (chickenpox) following which latent virus may reactivate decades later to produce herpes zoster (shingles), as well as an increasingly recognized number of subacute, acute and chronic neurological conditions. Following primary infection, both viruses establish a latent infection in neuronal cells in human peripheral ganglia. However, the detailed mechanisms of viral latency and reactivation have yet to be unravelled. In both cases latent viral DNA exists in an 'end-less' state where the ends of the virus genome are joined to form structures consistent with unit length episomes and concatemers, from which viral gene transcription is restricted. In latently infected ganglia, the most abundantly detected HSV-1 RNAs are the spliced products originating from the primary latency associated transcript (LAT). This primary LAT is an 8.3 kb unstable transcript from which two stable (1.5 and 2.0 kb) introns are spliced. Transcripts mapping to 12 VZV genes have been detected in human ganglia removed at autopsy; however, it is difficult to ascribe these as transcripts present during latent infection as early-stage virus reactivation may have transpired in the post-mortem time period in the ganglia. Nonetheless, low-level transcription of VZV ORF63 has been repeatedly detected in multiple ganglia removed as close to death as possible. There is increasing

Ocular HSV-1: Is the Cornea a Reservoir for Viral Latency or a Fast Pit Stop?

PubMed Central

Kennedy, David P.; Clement, Christian; Arceneaux, Richard L.; Bhattacharjee, Partha S.; Huq, Tashfin S.; Hill, James M.

2010-01-01

Purpose To present a review supporting and refuting evidence from mouse, rabbit, non-human primate, and human studies of herpes simplex virus type 1 (HSV-1) concerning corneal latency. Methods More than 50 research papers on HSV-1 published in peer-reviewed journals were examined. Results Infectious HSV-1 has been found in mouse denervated tissues and in tissues with negative cultures from the corresponding ganglion. However, the different mouse strains have shown varied responses to different strains of HSV, making it difficult to relate such findings to humans. Rabbit studies provide excellent evidence for HSV-1 corneal latency including data on HSV-1 migration from the cornea into the corneoscleral rim and on the distribution of HSV-1 DNA in the cornea. However, the available methods for the detection of infectious HSV-1 may not be sensitive enough to detect low-level infection. Infectious HSV-1 has been successfully isolated from the tears of non-human primates in the absence of detectable corneal lesions. The recurrence of corneal ulcers in non-human primates before the appearance of infectious HSV-1 in tears suggests that the origin of the HSV-1 is the cornea, rather than the TG. Human studies presented evidence of both ganglion and corneal latency. Conclusion Understanding HSV-1 disease progression and the possibility of corneal latency could lead to more effective treatments for herpetic keratitis. However, it is unlikely that operational latency in the cornea will be definitively proven unless a new method with higher sensitivity for the detection of infectious virus is developed. PMID:21304287

Stochastic Game Analysis and Latency Awareness for Self-Adaptation

DTIC Science & Technology

2014-01-01

this paper, we introduce a formal analysis technique based on model checking of stochastic multiplayer games (SMGs) that enables us to quantify the...Additional Key Words and Phrases: Proactive adaptation, Stochastic multiplayer games , Latency 1. INTRODUCTION When planning how to adapt, self-adaptive...contribution of this paper is twofold: (1) A novel analysis technique based on model checking of stochastic multiplayer games (SMGs) that enables us to

Recovery cycle times of inferior colliculus neurons in the awake bat measured with spike counts and latencies

PubMed Central

Sayegh, Riziq; Aubie, Brandon; Fazel-Pour, Siavosh; Faure, Paul A.

2012-01-01

Neural responses in the mammalian auditory midbrain (inferior colliculus; IC) arise from complex interactions of synaptic excitation, inhibition, and intrinsic properties of the cell. Temporally selective duration-tuned neurons (DTNs) in the IC are hypothesized to arise through the convergence of excitatory and inhibitory synaptic inputs offset in time. Synaptic inhibition can be inferred from extracellular recordings by presenting pairs of pulses (paired tone stimulation) and comparing the evoked responses of the cell to each pulse. We obtained single unit recordings from the IC of the awake big brown bat (Eptesicus fuscus) and used paired tone stimulation to measure the recovery cycle times of DTNs and non-temporally selective auditory neurons. By systematically varying the interpulse interval (IPI) of the paired tone stimulus, we determined the minimum IPI required for a neuron's spike count or its spike latency (first- or last-spike latency) in response to the second tone to recover to within ≥50% of the cell's baseline count or to within 1 SD of it's baseline latency in response to the first tone. Recovery times of shortpass DTNs were significantly shorter than those of bandpass DTNs, and recovery times of bandpass DTNs were longer than allpass neurons not selective for stimulus duration. Recovery times measured with spike counts were positively correlated with those measured with spike latencies. Recovery times were also correlated with first-spike latency (FSL). These findings, combined with previous studies on duration tuning in the IC, suggest that persistent inhibition is a defining characteristic of DTNs. Herein, we discuss measuring recovery times of neurons with spike counts and latencies. We also highlight how persistent inhibition could determine neural recovery times and serve as a potential mechanism underlying the precedence effect in humans. Finally, we explore implications of recovery times for DTNs in the context of bat hearing and

Round window closure affects cochlear responses to suprathreshold stimuli.

PubMed

Cai, Qunfeng; Whitcomb, Carolyn; Eggleston, Jessica; Sun, Wei; Salvi, Richard; Hu, Bo Hua

2013-12-01

The round window acts as a vent for releasing inner ear pressure and facilitating basilar membrane vibration. Loss of this venting function affects cochlear function, which leads to hearing impairment. In an effort to identify functional changes that might be used in clinical diagnosis of round window atresia, the current investigation was designed to examine how the cochlea responds to suprathreshold stimuli following round window closure. Prospective, controlled, animal study. A rat model of round window occlusion (RWO) was established. With this model, the thresholds of auditory brainstem responses (ABR) and the input/output (IO) functions of distortion product otoacoustic emissions (DPOAEs) and acoustic startle responses were examined. Round window closure caused a mild shift in the thresholds of the auditory brainstem response (13.5 ± 9.1 dB). It also reduced the amplitudes of the distortion product otoacoustic emissions and the slope of the input/output functions. This peripheral change was accompanied by a significant reduction in the amplitude, but not the threshold, of the acoustic startle reflex, a motor response to suprathreshold sounds. In addition to causing mild increase in the threshold of the auditory brainstem response, round window occlusion reduced the slopes of both distortion product otoacoustic emissions and startle reflex input/output functions. These changes differ from those observed for typical conductive or sensory hearing loss, and could be present in patients with round window atresia. However, future clinical observations in patients are needed to confirm these findings. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

Antibody-Independent Control of γ-Herpesvirus Latency via B Cell Induction of Anti-Viral T Cell Responses

PubMed Central

McClellan, Kelly B; Gangappa, Shivaprakash; Speck, Samuel H; Virgin, Herbert W.

2006-01-01

B cells can use antibody-dependent mechanisms to control latent viral infections. It is unknown whether this represents the sole function of B cells during chronic viral infection. We report here that hen egg lysozyme (HEL)-specific B cells can contribute to the control of murine γ-herpesvirus 68 (γHV68) latency without producing anti-viral antibody. HEL-specific B cells normalized defects in T cell numbers and proliferation observed in B cell−/− mice during the early phase of γHV68 latency. HEL-specific B cells also reversed defects in CD8 and CD4 T cell cytokine production observed in B cell−/− mice, generating CD8 and CD4 T cells necessary for control of latency. Furthermore, HEL-specific B cells were able to present virally encoded antigen to CD8 T cells. Therefore, B cells have antibody independent functions, including antigen presentation, that are important for control of γ-herpesvirus latency. Exploitation of this property of B cells may allow enhanced vaccine responses to chronic virus infection. PMID:16789842

User Needs and Assessing the Impact of Low Latency NASA Earth Observation Data Availability on Societal Benefit

NASA Technical Reports Server (NTRS)

Brown, Molly E.; Carroll, Mark L.; Escobar, Vanessa M.

2014-01-01

Since the advent of NASA's Earth Observing System, knowledge of the practical benefits of Earth science data has grown considerably. The community using NASA Earth science observations in applications has grown significantly, with increasing sophistication to serve national interests. Data latency, or how quickly communities receive science observations after acquisition, can have a direct impact on the applications and usability of the information. This study was conducted to determine how users are incorporating NASA data into applications and operational processes to benefit society beyond scientific research, as well as to determine the need for data latency of less than 12 h. The results of the analysis clearly show the significant benefit to society of serving the needs of the agricultural, emergency response, environmental monitoring and weather communities who use rapidly delivered, accurate Earth science data. The study also showed the potential of expanding the communities who use low latency NASA science data products to provide new ways of transforming data into information. These benefits can be achieved with a clear and consistent NASA policy on product latency.

Low-latency Science Exploration of Planetary Bodies: a Demonstration Using ISS in Support of Mars Human Exploration

NASA Technical Reports Server (NTRS)

Thronson, Harley A.; Valinia, Azita; Bleacher, Jacob; Eigenbrode, Jennifer; Garvin, Jim; Petro, Noah

2014-01-01

We summarize a proposed experiment to use the International Space Station to formally examine the application and validation of low-latency telepresence for surface exploration from space as an alternative, precursor, or potentially as an adjunct to astronaut "boots on the ground." The approach is to develop and propose controlled experiments, which build upon previous field studies and which will assess the effects of different latencies (0 to 500 msec), task complexity, and alternate forms of feedback to the operator. These experiments serve as an example of a pathfinder for NASA's roadmap of missions to Mars with low-latency telerobotic exploration as a precursor to astronaut's landing on the surface to conduct geological tasks.

Act quickly, decide later: long-latency visual processing underlies perceptual decisions but not reflexive behavior.

PubMed

Jolij, Jacob; Scholte, H Steven; van Gaal, Simon; Hodgson, Timothy L; Lamme, Victor A F

2011-12-01

Humans largely guide their behavior by their visual representation of the world. Recent studies have shown that visual information can trigger behavior within 150 msec, suggesting that visually guided responses to external events, in fact, precede conscious awareness of those events. However, is such a view correct? By using a texture discrimination task, we show that the brain relies on long-latency visual processing in order to guide perceptual decisions. Decreasing stimulus saliency leads to selective changes in long-latency visually evoked potential components reflecting scene segmentation. These latency changes are accompanied by almost equal changes in simple RTs and points of subjective simultaneity. Furthermore, we find a strong correlation between individual RTs and the latencies of scene segmentation related components in the visually evoked potentials, showing that the processes underlying these late brain potentials are critical in triggering a response. However, using the same texture stimuli in an antisaccade task, we found that reflexive, but erroneous, prosaccades, but not antisaccades, can be triggered by earlier visual processes. In other words: The brain can act quickly, but decides late. Differences between our study and earlier findings suggesting that action precedes conscious awareness can be explained by assuming that task demands determine whether a fast and unconscious, or a slower and conscious, representation is used to initiate a visually guided response.

WindTalker: A P2P-Based Low-Latency Anonymous Communication Network

NASA Astrophysics Data System (ADS)

Zhang, Jia; Duan, Haixin; Liu, Wu; Wu, Jianping

Compared with traditional static anonymous communication networks, the P2P architecture can provide higher anonymity in communication. However, the P2P architecture also leads to more challenges, such as route, stability, trust and so on. In this paper, we present WindTalker, a P2P-based low-latency anonymous communication network. It is a pure decentralized mix network and can provide low-latency services which help users hide their real identity in communication. In order to ensure stability and reliability, WindTalker imports “seed nodes” to help a peer join in the P2P network and the peer nodes can use gossip-based protocol to exchange active information. Moreover, WindTalker uses layer encryption to ensure the information of relayed messages cannot be leaked. In addition, malicious nodes in the network are the major threat to anonymity of P2P anonymous communication, so WindTalker imports a trust mechanism which can help the P2P network exclude malicious nodes and optimize the strategy of peer discovery, tunnel construction, and relaying etc. in anonymous communications. We deploy peer nodes of WindTalker in our campus network to test reliability and analyze anonymity in theory. The network measurement and simulation analysis shows that WindTalker can provide low-latency and reliable anonymous communication services.

Epigenetic dysregulation of epstein-barr virus latency and development of autoimmune disease.

PubMed

Niller, Hans Helmut; Wolf, Hans; Ay, Eva; Minarovits, Janos

2011-01-01

Epstein-Barr virus (EBV) is ahumanherpesvirus thatpersists in the memory B-cells of the majority of the world population in a latent form. Primary EBV infection is asymptomatic or causes a self-limiting disease, infectious mononucleosis. Virus latency is associated with a wide variety of neoplasms whereof some occur in immune suppressed individuals. Virus production does not occur in strict latency. The expression of latent viral oncoproteins and nontranslated RNAs is under epigenetic control via DNA methylation and histone modifications that results either in a complete silencing of the EBV genome in memory B cells, or in a cell-type dependent usage of a couple of latency promoters in tumor cells, germinal center B cells and lymphoblastoid cells (LCL, transformed by EBV in vitro). Both, latent and lytic EBV proteins elicit a strong immune response. In immune suppressed and infectious mononucleosis patients, an increased viral load can be detected in the blood. Enhanced lytic replication may result in new infection- and transformation-events and thus is a risk factor both for malignant transformation and the development of autoimmune diseases. An increased viral load or a changed presentation of a subset of lytic or latent EBV proteins that cross-react with cellular antigens may trigger pathogenic processes through molecular mimicry that result in multiple sclerosis (MS), systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

Preterm delivery at low gestational age: risk factors for short latency. A multivariated analysis

PubMed Central

Marzano, Sara; Padula, Francesco; Meloni, Paolo; Anceschi, Maurizio Marco

2008-01-01

Objective The aim of this study is to identify the risk factors for a short latency in preterm delivery at low gestational ages (GA). Study design A retrospective analysis involving, between January 2004 and May 2006, 204 singleton pregnancies with admission diagnosis of preterm labor and, in particular, 91 pregnant women admitted between 24+0 and 31+6 weeks’ gestation. Results In pregnant women with a diagnosis of preterm labor at 24-31+6 weeks’ gestation, at ROC curve, a value of considering WBC and cervical dilatation, combined in the following formula (75.237 - (2.290 * “WBC”) - (10.787 * “cervical dilatation”)) <=33.101 has a 74.2% Sensitivity and a 78.3% Specificity in predicting a latency =< 4 days (+LR 3.42 and -LR 0.33) and a 70% Sensitivity and a 84.3% Specificity in predicting GA at delivery at 24-31 weeks’ gestation (+LR 4.46 and -LR 0.36). Conclusion We suggest a more strictly monitoring and a more aggressive therapy in presence of prognostic parameters of shorter latency. PMID:22439021

Bifurcated method and apparatus for floating point addition with decreased latency time

DOEpatents

Farmwald, Paul M.

1987-01-01

Apparatus for decreasing the latency time associated with floating point addition and subtraction in a computer, using a novel bifurcated, pre-normalization/post-normalization approach that distinguishes between differences of floating point exponents.

Delayed Latency of Postural Muscles of Individuals with Intellectual Disabilities.

PubMed

Tolentino-Castro, J Walter; Mühlbeier, Andreas; Mochizuki, Luis; Wagner, Heiko

2018-01-01

Individuals with intellectual disabilities (ID) (50 < IQ < 79) show impaired motor and postural control, these impairments are highly related to falls and injuries. Recent studies demonstrated these impairments are related with fine and gross motor development, which are more strongly associated with cognition, and consequently language for individuals with ID than for without ID. Despite these studies, little is known about the structure and functioning of this population's spinal cord, which is highly involved in postural control. The aim of our study was to assess the latency of the reflex responses in postural muscles after unexpected lateral external perturbations, in individuals with intellectual disabilities compared to typically developed participants. We assessed 16 participants with intellectual disabilities, 9 males and 7 females (aged 24.06 ± 8.66 years) and 20 typical developed participants (CG), 11 females, 9 males, (aged 21.20±1.96 years). While the participants were in an upright standing position electromyography was used to collect data from M. obliquus externus abdominis (OE) muscles, which were activated by unpredictable perturbations applied by a servomotor on a hand-held grip, following the lateral external perturbation to the trunk. The intellectual disabilities group presented contralateral OE muscles latency of 85.71±27.24 ms, and CG group presented 68.62±10.25 ms, no differences was found. Ipsilateral OE muscles latency also did not differs between the groups, ID group showed 96.60±30.20 ms and CG group showed 95.57±33.53 ms. Our study furthers the knowledge about the muscular activity of individuals with intellectual disabilities. The present experimental results may suggest unique spinal cord processing of individuals with intellectual disabilities when they are faced with unexpected lateral external perturbations.

Vestibular short latency responses to pulsed linear acceleration in unanesthetized animals

NASA Technical Reports Server (NTRS)

Jones, T. A.

1992-01-01

Linear acceleration transients were used to elicit vestibular compound action potentials in non-invasively prepared, unanesthetized animals for the first time (chicks, Gallus domesticus, n = 33). Responses were composed of a series of up to 8 dominant peaks occurring within 8 msec of the stimulus. Response amplitudes for 1.0 g stimulus ranged from 1 to 10 microV. A late, slow, triphasic, anesthesia-labile component was identified as a dominant response feature in unanesthetized animals. Amplitudes increased and latencies decreased as stimulus intensity was increased (MANOVA P less than 0.05). Linear regression slope ranges were: amplitudes = 1.0-5.0 microV/g; latencies = -300 to -1100 microseconds/g. Thresholds for single polarity stimuli (0.035 +/- 0.022 g, n = 11) were significantly lower than those of alternating polarity (0.074 +/- 0.028 g, n = 18, P less than 0.001). Bilateral labyrinthectomy eliminated responses whereas bilateral extirpation of cochleae did not significantly change response thresholds. Intense acoustic masking (100/104 dB SL) produced no effect in 2 animals, but did produce small to moderate effects on response amplitudes in 7 others. Changes were attributed to effects on vestibular end organs. Results of unilateral labyrinth blockade (tetrodotoxin) suggest that P1 and N1 preferentially reflect ipsilateral eighth nerve compound action potentials whereas components beyond approximately 2 msec reflect activity from vestibular neurons that depend on both labyrinths. The results demonstrate that short latency vestibular compound action potentials can be measured in unanesthetized, non-invasively prepared animals.

Silent latency periods in methylmercury poisoning and in neurodegenerative disease.

PubMed Central

Weiss, Bernard; Clarkson, Thomas W; Simon, William

2002-01-01

This article discusses three examples of delay (latency) in the appearance of signs and symptoms of poisoning after exposure to methylmercury. First, a case is presented of a 150-day delay period before the clinical manifestations of brain damage after a single brief (<1 day) exposure to dimethylmercury. The second example is taken from the Iraq outbreak of methylmercury poisoning in which the victims consumed contaminated bread for several weeks without any ill effects. Indeed, signs of poisoning did not appear until weeks or months after exposure stopped. The last example is drawn from observations on nonhuman primates and from the sequelae of the Minamata, Japan, outbreak in which low chronic doses of methylmercury may not have produced observable behavioral effects for periods of time measured in years. The mechanisms of these latency periods are discussed for both acute and chronic exposures. Parallels are drawn with other diseases that affect the central nervous system, such as Parkinson disease and post-polio syndrome, that also reflect the delayed appearance of central nervous system damage. PMID:12426145

Silent latency periods in methylmercury poisoning and in neurodegenerative disease.

PubMed

Weiss, Bernard; Clarkson, Thomas W; Simon, William

2002-10-01

This article discusses three examples of delay (latency) in the appearance of signs and symptoms of poisoning after exposure to methylmercury. First, a case is presented of a 150-day delay period before the clinical manifestations of brain damage after a single brief (<1 day) exposure to dimethylmercury. The second example is taken from the Iraq outbreak of methylmercury poisoning in which the victims consumed contaminated bread for several weeks without any ill effects. Indeed, signs of poisoning did not appear until weeks or months after exposure stopped. The last example is drawn from observations on nonhuman primates and from the sequelae of the Minamata, Japan, outbreak in which low chronic doses of methylmercury may not have produced observable behavioral effects for periods of time measured in years. The mechanisms of these latency periods are discussed for both acute and chronic exposures. Parallels are drawn with other diseases that affect the central nervous system, such as Parkinson disease and post-polio syndrome, that also reflect the delayed appearance of central nervous system damage.

Long latency postural responses are functionally modified by cognitive set.

PubMed

Beckley, D J; Bloem, B R; Remler, M P; Roos, R A; Van Dijk, J G

1991-10-01

We examined how cognitive set influences the long latency components of normal postural responses in the legs. We disturbed the postural stability of standing human subjects with sudden toe-up ankle rotations. To influence the subjects' cognitive set, we varied the rotation amplitude either predictably (serial 4 degrees versus serial 10 degrees) or unpredictably (random mixture of 4 degrees and 10 degrees). The subjects' responses to these ankle rotations were assessed from the EMG activity of the tibialis anterior, the medial gastrocnemius, and the vastus lateralis muscles of the left leg. The results indicate that, when the rotation amplitude is predictable, only the amplitude of the long latency (LL) response in tibialis anterior and vastus lateralis varied directly with perturbation size. Furthermore, when the rotation amplitude is unpredictable, the central nervous system selects a default amplitude for the LL response in the tibialis anterior. When normal subjects are exposed to 2 perturbation amplitudes which include the potential risk of falling, the default LL response in tibialis anterior appropriately anticipates the larger amplitude perturbation rather than the smaller or an intermediate one.

Comparison of actigraphy immobility rules with polysomnographic sleep onset latency in children and adolescents.

PubMed

Meltzer, Lisa J; Walsh, Colleen M; Peightal, Ashley A

2015-12-01

While actigraphy has gained popularity in pediatric sleep research, questions remain about the validity of actigraphy as an estimate of sleep-wake patterns. In particular, there is little consistency in the field in terms of scoring rules used to determine sleep onset latency. The purpose of this study was to evaluate different criteria of immobility as a measure of sleep onset latency in children and adolescents. Ninety-five youth (ages 3-17 years, 46 % male) wore both the Ambulatory Monitoring Inc. Motionlogger Sleep Watch (AMI) and the Philips Respironics Mini-Mitter Actiwatch-2 (PRMM) during overnight polysomnography in a pediatric sleep lab. We examined different sleep onset latency scoring rules (3, 5, 10, 15, and 20 min of immobility) using different algorithms (Sadeh and Cole-Kripke) and sensitivity settings (low, medium, high) for the devices. Comparisons were also made across age groups (preschoolers, school-aged, adolescents) and sleep disordered breathing status (no obstructive sleep apnea [OSA], mild OSA, clinically significant OSA). For the AMI device, shorter scoring rules performed best for children and longer scoring rules were better for adolescents, with shorter scoring rules best across sleep disordered breathing groups. For the PRMM device, medium to longer scoring rules performed best across age and sleep disordered breathing groups. Researchers are encouraged to determine the scoring rule that best fits their population of interest. Future studies are needed with larger samples of children and adolescents to further validate actigraphic immobility as a proxy for sleep onset latency.

Comparison of Actigraphy Immobility Rules with Polysomnographic Sleep Onset Latency in Children and Adolescents

PubMed Central

Meltzer, Lisa J.; Walsh, Colleen M.; Peightal, Ashley A.

2015-01-01

Purpose While actigraphy has gained popularity in pediatric sleep research, questions remain about the validity of actigraphy as an estimate of sleep-wake patterns. In particular, there is little consistency in the field in terms of scoring rules used to determine sleep onset latency. The purpose of this study was to evaluate different criteria of immobility as a measure of sleep onset latency in children and adolescents. Methods Ninety-five youth (ages 3-17 years, 46% male) wore both the Ambulatory-Monitoring Inc. Motionlogger Sleep Watch (AMI) and the Philips Respironics Mini-Mitter Actiwatch-2 (PRMM) during overnight polysomnography in a pediatric sleep lab. We examined different sleep onset latency scoring rules (3, 5, 10, 15, and 20 minutes of immobility) using different algorithms (Sadeh and Cole-Kripke) and sensitivity settings (Low, Medium, High) for the devices. Comparisons were also made across age groups (preschoolers, school-aged, adolescents) and sleep disordered breathing status (no obstructive sleep apnea [OSA], mild OSA, clinically significant OSA). Results For the AMI device, shorter scoring rules performed best for children and longer scoring rules were better for adolescents, with shorter scoring rules best across sleep disordered breathing groups. For the PRMM device, medium to longer scoring rules performed best across age and sleep disordered breathing groups. Conclusions Researchers are encouraged to determine the scoring rule that best fits their population of interest. Future studies are needed with larger samples of children and adolescents to further validate actigraphic immobility as a proxy for sleep onset latency. PMID:25687438

A Paradox of Syntactic Priming: Why Response Tendencies Show Priming for Passives, and Response Latencies Show Priming for Actives

PubMed Central

Segaert, Katrien; Menenti, Laura; Weber, Kirsten; Hagoort, Peter

2011-01-01

Speakers tend to repeat syntactic structures across sentences, a phenomenon called syntactic priming. Although it has been suggested that repeating syntactic structures should result in speeded responses, previous research has focused on effects in response tendencies. We investigated syntactic priming effects simultaneously in response tendencies and response latencies for active and passive transitive sentences in a picture description task. In Experiment 1, there were priming effects in response tendencies for passives and in response latencies for actives. However, when participants' pre-existing preference for actives was altered in Experiment 2, syntactic priming occurred for both actives and passives in response tendencies as well as in response latencies. This is the first investigation of the effects of structure frequency on both response tendencies and latencies in syntactic priming. We discuss the implications of these data for current theories of syntactic processing. PMID:22022352

Analog Testing of Operations Concepts for Mitigation of Communication Latency During Human Space Exploration

NASA Technical Reports Server (NTRS)

Chappell, Steven P.; Abercromby, Andrew F.; Miller, Matthew J.; Halcon, Christopher; Gernhardt, Michael L.

2016-01-01

OBJECTIVES: NASA Extreme Environment Mission Operations (NEEMO) is an underwater spaceflight analog that allows a true mission-like operational environment and uses buoyancy effects and added weight to simulate different gravity levels. Three missions were undertaken from 2014-2015, NEEMO's 18-20. All missions were performed at the Aquarius undersea research habitat. During each mission, the effects of varying operations concepts and tasks type and complexity on representative communication latencies associated with Mars missions were studied. METHODS: 12 subjects (4 per mission) were weighed out to simulate near-zero or partial gravity extravehicular activity (EVA) and evaluated different operations concepts for integration and management of a simulated Earth-based science backroom team (SBT) to provide input and direction during exploration activities. Exploration traverses were planned in advance based on precursor data collected. Subjects completed science-related tasks including presampling surveys, geologic-based sampling, and marine-based sampling as a portion of their tasks on saturation dives up to 4 hours in duration that were to simulate extravehicular activity (EVA) on Mars or the moons of Mars. One-way communication latencies, 5 and 10 minutes between space and mission control, were simulated throughout the missions. Objective data included task completion times, total EVA times, crew idle time, translation time, SBT assimilation time (defined as time available for SBT to discuss data/imagery after it has been collected, in addition to the time taken to watch imagery streaming over latency). Subjective data included acceptability, simulation quality, capability assessment ratings, and comments. RESULTS: Precursor data can be used effectively to plan and execute exploration traverse EVAs (plans included detailed location of science sites, high-fidelity imagery of the sites, and directions to landmarks of interest within a site). Operations concepts that

Fuzzy Logic based Handoff Latency Reduction Mechanism in Layer 2 of Heterogeneous Mobile IPv6 Networks

NASA Astrophysics Data System (ADS)

Anwar, Farhat; Masud, Mosharrof H.; Latif, Suhaimi A.

2013-12-01

Mobile IPv6 (MIPv6) is one of the pioneer standards that support mobility in IPv6 environment. It has been designed to support different types of technologies for providing seamless communications in next generation network. However, MIPv6 and subsequent standards have some limitations due to its handoff latency. In this paper, a fuzzy logic based mechanism is proposed to reduce the handoff latency of MIPv6 for Layer 2 (L2) by scanning the Access Points (APs) while the Mobile Node (MN) is moving among different APs. Handoff latency occurs when the MN switches from one AP to another in L2. Heterogeneous network is considered in this research in order to reduce the delays in L2. Received Signal Strength Indicator (RSSI) and velocity of the MN are considered as the input of fuzzy logic technique. This technique helps the MN to measure optimum signal quality from APs for the speedy mobile node based on fuzzy logic input rules and makes a list of interfaces. A suitable interface from the list of available interfaces can be selected like WiFi, WiMAX or GSM. Simulation results show 55% handoff latency reduction and 50% packet loss improvement in L2 compared to standard to MIPv6.

Corelli: a peer-to-peer dynamic replication service for supporting latency-dependent content in community networks

NASA Astrophysics Data System (ADS)

Tyson, Gareth; Mauthe, Andreas U.; Kaune, Sebastian; Mu, Mu; Plagemann, Thomas

2009-01-01

The quality of service for latency dependent content, such as video streaming, largely depends on the distance and available bandwidth between the consumer and the content. Poor provision of these qualities results in reduced user experience and increased overhead. To alleviate this, many systems operate caching and replication, utilising dedicated resources to move the content closer to the consumer. Latency-dependent content creates particular issues for community networks, which often display the property of strong internal connectivity yet poor external connectivity. However, unlike traditional networks, communities often cannot deploy dedicated infrastructure for both monetary and practical reasons. To address these issues, this paper proposes Corelli, a peer-to-peer replication infrastructure designed for use in community networks. In Corelli, high capacity peers in communities autonomously build a distributed cache to dynamically pre-fetch content early on in its popularity lifecycle. By exploiting the natural proximity of peers in the community, users can gain extremely low latency access to content whilst reducing egress utilisation. Through simulation, it is shown that Corelli considerably increases accessibility and improves performance for latency dependent content. Further, Corelli is shown to offer adaptive and resilient mechanisms that ensure that it can respond to variations in churn, demand and popularity.

Zebra Alphaherpesviruses (EHV-1 and EHV-9): Genetic Diversity, Latency and Co-Infections.

PubMed

Abdelgawad, Azza; Damiani, Armando; Ho, Simon Y W; Strauss, Günter; Szentiks, Claudia A; East, Marion L; Osterrieder, Nikolaus; Greenwood, Alex D

2016-09-20

Alphaherpesviruses are highly prevalent in equine populations and co-infections with more than one of these viruses' strains frequently diagnosed. Lytic replication and latency with subsequent reactivation, along with new episodes of disease, can be influenced by genetic diversity generated by spontaneous mutation and recombination. Latency enhances virus survival by providing an epidemiological strategy for long-term maintenance of divergent strains in animal populations. The alphaherpesviruses equine herpesvirus 1 (EHV-1) and 9 (EHV-9) have recently been shown to cross species barriers, including a recombinant EHV-1 observed in fatal infections of a polar bear and Asian rhinoceros. Little is known about the latency and genetic diversity of EHV-1 and EHV-9, especially among zoo and wild equids. Here, we report evidence of limited genetic diversity in EHV-9 in zebras, whereas there is substantial genetic variability in EHV-1. We demonstrate that zebras can be lytically and latently infected with both viruses concurrently. Such a co-occurrence of infection in zebras suggests that even relatively slow-evolving viruses such as equine herpesviruses have the potential to diversify rapidly by recombination. This has potential consequences for the diagnosis of these viruses and their management in wild and captive equid populations.

Diesel exhaust causing low-dose irritant asthma with latency?

PubMed

Adewole, Femi; Moore, Vicky C; Robertson, Alastair S; Burge, P S

2009-09-01

Diesel exhaust exposure may cause acute irritant-induced asthma and potentiate allergen-induced asthma. There are no previous reports of occupational asthma due to diesel exhaust. To describe occupational asthma with latency in workers exposed to diesel exhaust in bus garages. The Shield database of occupational asthma notifications in the West Midlands, UK, was searched between 1990 and 2006 for workers where diesel exhaust exposure was thought to be the cause of the occupational asthma. Those without other confounding exposures whose occupational asthma was validated by serial peak expiratory flow (PEF) analysis using Oasys software were included. Fifteen workers were identified with occupational asthma attributed to diesel exhaust. Three had validated new-onset asthma with latency. All worked in bus garages where diesel exhaust exposure was the only likely cause of their occupational asthma. Occupational asthma was confirmed by measures of non-specific reactivity and serial measurements of PEF with Oasys scores of 2.9, 3.73 and 4 (positive score > 2.5). The known non-specific irritant effects of diesel exhaust suggest that this is an example of low-dose irritant-induced asthma and that exposures to diesel exhaust in at least some bus garages are at a sufficient level to cause this.

HIV-1 Latency: An Update of Molecular Mechanisms and Therapeutic Strategies

PubMed Central

Battistini, Angela; Sgarbanti, Marco

2014-01-01

The major obstacle towards HIV-1 eradication is the life-long persistence of the virus in reservoirs of latently infected cells. In these cells the proviral DNA is integrated in the host’s genome but it does not actively replicate, becoming invisible to the host immune system and unaffected by existing antiviral drugs. Rebound of viremia and recovery of systemic infection that follows interruption of therapy, necessitates life-long treatments with problems of compliance, toxicity, and untenable costs, especially in developing countries where the infection hits worst. Extensive research efforts have led to the proposal and preliminary testing of several anti-latency compounds, however, overall, eradication strategies have had, so far, limited clinical success while posing several risks for patients. This review will briefly summarize the more recent advances in the elucidation of mechanisms that regulates the establishment/maintenance of latency and therapeutic strategies currently under evaluation in order to eradicate HIV persistence. PMID:24736215

A comparison of herpes simplex virus type 1 and varicella-zoster virus latency and reactivation

PubMed Central

Kennedy, Peter G. E.; Rovnak, Joel; Badani, Hussain

2015-01-01

Herpes simplex virus type 1 (HSV-1; human herpesvirus 1) and varicella-zoster virus (VZV; human herpesvirus 3) are human neurotropic alphaherpesviruses that cause lifelong infections in ganglia. Following primary infection and establishment of latency, HSV-1 reactivation typically results in herpes labialis (cold sores), but can occur frequently elsewhere on the body at the site of primary infection (e.g. whitlow), particularly at the genitals. Rarely, HSV-1 reactivation can cause encephalitis; however, a third of the cases of HSV-1 encephalitis are associated with HSV-1 primary infection. Primary VZV infection causes varicella (chickenpox) following which latent virus may reactivate decades later to produce herpes zoster (shingles), as well as an increasingly recognized number of subacute, acute and chronic neurological conditions. Following primary infection, both viruses establish a latent infection in neuronal cells in human peripheral ganglia. However, the detailed mechanisms of viral latency and reactivation have yet to be unravelled. In both cases latent viral DNA exists in an ‘end-less’ state where the ends of the virus genome are joined to form structures consistent with unit length episomes and concatemers, from which viral gene transcription is restricted. In latently infected ganglia, the most abundantly detected HSV-1 RNAs are the spliced products originating from the primary latency associated transcript (LAT). This primary LAT is an 8.3 kb unstable transcript from which two stable (1.5 and 2.0 kb) introns are spliced. Transcripts mapping to 12 VZV genes have been detected in human ganglia removed at autopsy; however, it is difficult to ascribe these as transcripts present during latent infection as early-stage virus reactivation may have transpired in the post-mortem time period in the ganglia. Nonetheless, low-level transcription of VZV ORF63 has been repeatedly detected in multiple ganglia removed as close to death as possible. There is

LMP1-Induced Sumoylation Influences the Maintenance of Epstein-Barr Virus Latency through KAP1

PubMed Central

Moss, Charles Randall; Whitehurst, Christopher B.; Moody, Cary A.

2015-01-01

ABSTRACT As a herpesvirus, Epstein-Barr virus (EBV) establishes a latent infection that can periodically undergo reactivation, resulting in lytic replication and the production of new infectious virus. Latent membrane protein-1 (LMP1), the principal viral oncoprotein, is a latency-associated protein implicated in regulating viral reactivation and the maintenance of latency. We recently found that LMP1 hijacks the SUMO-conjugating enzyme Ubc9 via its C-terminal activating region-3 (CTAR3) and induces the sumoylation of cellular proteins. Because protein sumoylation can promote transcriptional repression, we hypothesized that LMP1-induced protein sumoylation induces the repression of EBV lytic promoters and helps maintain the viral genome in its latent state. We now show that with inhibition of LMP1-induced protein sumoylation, the latent state becomes less stable or leakier in EBV-transformed lymphoblastoid cell lines. The cells are also more sensitive to viral reactivation induced by irradiation, which results in the increased production and release of infectious virus, as well as increased susceptibility to ganciclovir treatment. We have identified a target of LMP1-mediated sumoylation that contributes to the maintenance of latency in this context: KRAB-associated protein-1 (KAP1). LMP1 CTAR3-mediated sumoylation regulates the function of KAP1. KAP1 also binds to EBV OriLyt and immediate early promoters in a CTAR3-dependent manner, and inhibition of sumoylation processes abrogates the binding of KAP1 to these promoters. These data provide an additional line of evidence that supports our findings that CTAR3 is a distinct functioning regulatory region of LMP1 and confirm that LMP1-induced sumoylation may help stabilize the maintenance of EBV latency. IMPORTANCE Epstein-Barr virus (EBV) latent membrane protein-1 (LMP1) plays an important role in the maintenance of viral latency. Previously, we documented that LMP1 targets cellular proteins to be modified by a

Temporal dynamics of choice behavior in rats and humans: an examination of pre- and post-choice latencies

PubMed Central

Fam, Justine; Westbrook, Fred; Arabzadeh, Ehsan

2016-01-01

Identifying similarities and differences in choice behavior across species is informative about how basic mechanisms give rise to more complex processes. In the present study, we compared pre- and post-choice latencies between rats and humans under two paradigms. In Experiment 1, we used a cued choice paradigm where subjects were presented with a cue that directed them as to which of two options to respond for rewards. In Experiment 2, subjects were free to choose between two options in order to procure rewards. In both Experiments rewards were delivered with distinct probabilities. The trial structure used in these experiments allowed the choice process to be decomposed into pre- and post-choice processes. Overall, post-choice latencies reflected the difference in reward probability between the two options, where latencies for the option with higher probability of reward were longer than those for the option with lower probability of reward. An interesting difference between rats and humans was observed: the choice behavior for humans, but not rats, was sensitive to the free-choice aspect of the tasks, such that in free-choice trials post-choice latencies no longer reflected the difference in reward probabilities between the two options. PMID:26862000

Discrete Serotonin Systems Mediate Memory Enhancement and Escape Latencies after Unpredicted Aversive Experience in Drosophila Place Memory

PubMed Central

Sitaraman, Divya; Kramer, Elizabeth F.; Kahsai, Lily; Ostrowski, Daniela; Zars, Troy

2017-01-01

Feedback mechanisms in operant learning are critical for animals to increase reward or reduce punishment. However, not all conditions have a behavior that can readily resolve an event. Animals must then try out different behaviors to better their situation through outcome learning. This form of learning allows for novel solutions and with positive experience can lead to unexpected behavioral routines. Learned helplessness, as a type of outcome learning, manifests in part as increases in escape latency in the face of repeated unpredicted shocks. Little is known about the mechanisms of outcome learning. When fruit fly Drosophila melanogaster are exposed to unpredicted high temperatures in a place learning paradigm, flies both increase escape latencies and have a higher memory when given control of a place/temperature contingency. Here we describe discrete serotonin neuronal circuits that mediate aversive reinforcement, escape latencies, and memory levels after place learning in the presence and absence of unexpected aversive events. The results show that two features of learned helplessness depend on the same modulatory system as aversive reinforcement. Moreover, changes in aversive reinforcement and escape latency depend on local neural circuit modulation, while memory enhancement requires larger modulation of multiple behavioral control circuits. PMID:29321732

Brainstem auditory evoked potential wave V latency-intensity function in normal Dalmatian and Beagle puppies.

PubMed

Poncelet, L; Coppens, A; Deltenre, P

2000-01-01

This study investigated whether Dalmatian puppies with normal hearing bilaterally had the same click-evoked brainstem auditory potential characteristics as age-matched dogs of another breed. Short-latency brainstem auditory potentials evoked by condensation and rarefaction clicks were recorded in 23 1.5- to 2-month-old Dalmatian puppies with normal hearing bilaterally by a qualitative brainstem auditory evoked potential test and in 16 Beagle dogs of the same age. For each stimulus intensity, from 90 dB normal hearing level down to the wave V threshold, the sum of the potentials evoked by the 2 kinds of stimuli were added, giving an equivalent to the alternate click polarity stimulation. The slope of the L segment of the wave V latency-intensity curve was steeper in Dalmatian (-40 +/- 10 micros/dB) than in Beagles (-28 +/- 5 micros/dB, P < .001) puppies. The hearing threshold was lower in the Beagle puppies (P < .05). These results suggest that interbreed differences may exist at the level of cochlear function in this age class. The wave V latency and wave V-wave I latencies differences at high stimulus intensity were different between the groups of puppies (4.3 +/- 0.2 and 2.5 +/- 0.2 milliseconds, respectively, for Beagles; and 4.1 +/- 0.2 and 2.3 +/- 0.2 milliseconds for Dalmatians, P < .05). A different maturation speed of the neural pathways is one possible explanation of this observation.

The terminal latency of the phrenic nerve correlates with respiratory symptoms in amyotrophic lateral sclerosis.

PubMed

Park, Jin-Sung; Park, Donghwi

2017-09-01

The aim of the study was to investigate the electrophysiological parameters in phrenic nerve conduction studies (NCS) that sensitively reflect latent respiratory insufficiency present in amyotrophic lateral sclerosis (ALS). Forty-nine patients with ALS were examined, and after exclusion, 21 patients with ALS and their phrenic NCS results were reviewed. The patients were divided into two groups according to their respiratory sub-score in the ALS functional rating scale - revised (Group A, sub-score 12vs. Group B, sub-score 11). We compared the parameters of phrenic NCS between the two groups. There were no significant differences in the clinical characteristics between the two groups. Using a multivariate model, we found that the terminal latency of the phrenic nerve was the only parameter that was associated with early symptoms of respiratory insufficiency (p<0.05). The optimal cutoff value for the terminal latency of the phrenic nerve was 7.65ms (sensitivity 80%, specificity 68.2%). The significantly prolonged terminal latency of the phrenic nerve in our study may reflect a profound distal motor axonal dysfunction of the phrenic nerve in patients with ALS in the early stage of respiratory insufficiency that can be used as a sensitive electrophysiological marker reflecting respiratory symptoms in ALS. The terminal latency of the phrenic nerve is useful for early detection of respiratory insufficiency in patients with ALS. Copyright © 2017. Published by Elsevier B.V.

Influence of P300 latency jitter on event related potential-based brain-computer interface performance

NASA Astrophysics Data System (ADS)

Aricò, P.; Aloise, F.; Schettini, F.; Salinari, S.; Mattia, D.; Cincotti, F.

2014-06-01

Objective. Several ERP-based brain-computer interfaces (BCIs) that can be controlled even without eye movements (covert attention) have been recently proposed. However, when compared to similar systems based on overt attention, they displayed significantly lower accuracy. In the current interpretation, this is ascribed to the absence of the contribution of short-latency visual evoked potentials (VEPs) in the tasks performed in the covert attention modality. This study aims to investigate if this decrement (i) is fully explained by the lack of VEP contribution to the classification accuracy; (ii) correlates with lower temporal stability of the single-trial P300 potentials elicited in the covert attention modality. Approach. We evaluated the latency jitter of P300 evoked potentials in three BCI interfaces exploiting either overt or covert attention modalities in 20 healthy subjects. The effect of attention modality on the P300 jitter, and the relative contribution of VEPs and P300 jitter to the classification accuracy have been analyzed. Main results. The P300 jitter is higher when the BCI is controlled in covert attention. Classification accuracy negatively correlates with jitter. Even disregarding short-latency VEPs, overt-attention BCI yields better accuracy than covert. When the latency jitter is compensated offline, the difference between accuracies is not significant. Significance. The lower temporal stability of the P300 evoked potential generated during the tasks performed in covert attention modality should be regarded as the main contributing explanation of lower accuracy of covert-attention ERP-based BCIs.

Maturation of long latency auditory evoked potentials in hearing children: systematic review.

PubMed

Silva, Liliane Aparecida Fagundes; Magliaro, Fernanda Cristina Leite; Carvalho, Ana Claudia Martinho de; Matas, Carla Gentile

2017-05-15

To analyze how Auditory Long Latency Evoked Potentials (LLAEP) change according to age in children population through a systematic literature review. After formulation of the research question, a bibliographic survey was done in five data bases with the following descriptors: Electrophysiology (Eletrofisiologia), Auditory Evoked Potentials (Potenciais Evocados Auditivos), Child (Criança), Neuronal Plasticity (Plasticidade Neuronal) and Audiology (Audiologia). Level 1 evidence articles, published between 1995 and 2015 in Brazilian Portuguese or English language. Aspects related to emergence, morphology and latency of P1, N1, P2 and N2 components were analyzed. A total of 388 studies were found; however, only 21 studies contemplated the established criteria. P1 component is characterized as the most frequent component in young children, being observed around 100-150 ms, which tends to decrease as chronological age increases. The N2 component was shown to be the second most commonly observed component in children, being observed around 200-250 ms.. The other N1 and P2 components are less frequent and begin to be seen and recorded throughout the maturational process. The maturation of LLAEP occurs gradually, and the emergence of P1, N1, P2 and N2 components as well as their latency values are variable in childhood. P1 and N2 components are the most observed and described in pediatric population. The diversity of protocols makes the comparison between studies difficult.

Reducing the latency of the Fractal Iterative Method to half an iteration

NASA Astrophysics Data System (ADS)

Béchet, Clémentine; Tallon, Michel

2013-12-01

The fractal iterative method for atmospheric tomography (FRiM-3D) has been introduced to solve the wavefront reconstruction at the dimensions of an ELT with a low-computational cost. Previous studies reported the requirement of only 3 iterations of the algorithm in order to provide the best adaptive optics (AO) performance. Nevertheless, any iterative method in adaptive optics suffer from the intrinsic latency induced by the fact that one iteration can start only once the previous one is completed. Iterations hardly match the low-latency requirement of the AO real-time computer. We present here a new approach to avoid iterations in the computation of the commands with FRiM-3D, thus allowing low-latency AO response even at the scale of the European ELT (E-ELT). The method highlights the importance of "warm-start" strategy in adaptive optics. To our knowledge, this particular way to use the "warm-start" has not been reported before. Futhermore, removing the requirement of iterating to compute the commands, the computational cost of the reconstruction with FRiM-3D can be simplified and at least reduced to half the computational cost of a classical iteration. Thanks to simulations of both single-conjugate and multi-conjugate AO for the E-ELT,with FRiM-3D on Octopus ESO simulator, we demonstrate the benefit of this approach. We finally enhance the robustness of this new implementation with respect to increasing measurement noise, wind speed and even modeling errors.

Dyslipidemia and Auditory Function

PubMed Central

Evans, M. Bradley; Tonini, Ross; Shope, Cynthia Do; Oghalai, John S.; Jerger, James F.; Insull, William; Brownell, William E.

2013-01-01

The relationship between dyslipidemia and hearing is unclear. This study was conducted to investigate whether elevated serum lipid levels impact auditory function in humans and in guinea pigs. In the human study, a cross-sectional study of 40 volunteers with dyslipidemia was conducted. Pure tone thresholds, distortion product otoacoustic emissions, and lipid profiles were analyzed. When controlled for patient age and sex, we found that elevated triglycerides were associated with reduced hearing. In the guinea pig study, a prospective study of animals fed a high-fat diet for 14 weeks was conducted. Although the high-fat diet led to a dramatic elevation in the average weight and total cholesterol in all animals (from 61 to 589 mg/dl), there were no meaningful changes in distortion product otoacoustic emission magnitudes. These results suggest that whereas chronic dyslipidemia associated with elevated triglycerides may reduce auditory function, short-term dietary changes may not. PMID:16868509

Hearing status in patients with rheumatoid arthritis.

PubMed

Ahmadzadeh, A; Daraei, M; Jalessi, M; Peyvandi, A A; Amini, E; Ranjbar, L A; Daneshi, A

2017-10-01

Rheumatoid arthritis is thought to induce conductive hearing loss and/or sensorineural hearing loss. This study evaluated the function of the middle ear and cochlea, and the related factors. Pure tone audiometry, speech reception thresholds, speech discrimination scores, tympanometry, acoustic reflexes, and distortion product otoacoustic emissions were assessed in rheumatoid arthritis patients and healthy volunteers. Pure tone audiometry results revealed a higher bone conduction threshold in the rheumatoid arthritis group, but there was no significant difference when evaluated according to the sensorineural hearing loss definition. Distortion product otoacoustic emissions related prevalence of conductive or mixed hearing loss, tympanometry values, acoustic reflexes, and speech discrimination scores were not significantly different between the two groups. Sensorineural hearing loss was significantly more prevalent in patients who used azathioprine, cyclosporine and etanercept. Higher bone conduction thresholds in some frequencies were detected in rheumatoid arthritis patients that were not clinically significant. Sensorineural hearing loss is significantly more prevalent in refractory rheumatoid arthritis patients.

Electrically evoked reticular lamina and basilar membrane vibrations in mice with alpha tectorin C1509G mutation

NASA Astrophysics Data System (ADS)

Ren, Tianying; He, Wenxuan

2015-12-01

Mechanical coupling between the tectorial membrane and the hair bundles of outer hair cells is crucial for stimulating mechanoelectrical transduction channels, which convert sound-induced vibrations into electrical signal, and for transmitting outer hair cell-generated force back to the basilar membrane to boost hearing sensitivity. It has been demonstrated that the detached tectorial membrane in mice with C1509G alpha tectorin mutation caused hearing loss, but enhanced electrically evoked otoacoustic emissions. To understand how the mutated cochlea emits sounds, the reticular lamina and basilar membrane vibrations were measured in the electrically stimulated cochlea in this study. The results showed that the electrically evoked basilar membrane vibration decreased dramatically while the reticular lamina vibration and otoacoustic emissions exhibited no significant change in C1509G mutation mice. This result indicates that a functional cochlear amplifier and a normal basilar membrane vibration are not required for the outer hair cell-generated sound to exit the cochlea.

NEEMO 18-20: Analog Testing for Mitigation of Communication Latency During Human Space Exploration

NASA Technical Reports Server (NTRS)

Chappell, Steven P.; Beaton, Kara H.; Miller, Matthew J.; Graff, Trevor G.; Abercromby, Andrew F. J.; Gernhardt, Michael L.; Halcon, Christopher

2016-01-01

NASA Extreme Environment Mission Operations (NEEMO) is an underwater spaceflight analog that allows a true mission-like operational environment and uses buoyancy effects and added weight to simulate different gravity levels. Three missions were undertaken from 2014-2015, NEEMO's 18-20. All missions were performed at the Aquarius undersea research habitat. During each mission, the effects of communication latencies on operations concepts, timelines, and tasks were studied. METHODS: Twelve subjects (4 per mission) were weighed out to simulate near-zero or partial gravity extravehicular activity (EVA) and evaluated different operations concepts for integration and management of a simulated Earth-based science team (ST) to provide input and direction during exploration activities. Exploration traverses were preplanned based on precursor data. Subjects completed science-related tasks including pre-sampling surveys, geologic-based sampling, and marine-based sampling as a portion of their tasks on saturation dives up to 4 hours in duration that were designed to simulate extravehicular activity (EVA) on Mars or the moons of Mars. One-way communication latencies, 5 and 10 minutes between space and mission control, were simulated throughout the missions. Objective data included task completion times, total EVA times, crew idle time, translation time, ST assimilation time (defined as time available for ST to discuss data/imagery after data acquisition). Subjective data included acceptability, simulation quality, capability assessment ratings, and comments. RESULTS: Precursor data can be used effectively to plan and execute exploration traverse EVAs (plans included detailed location of science sites, high-fidelity imagery of the sites, and directions to landmarks of interest within a site). Operations concepts that allow for pre-sampling surveys enable efficient traverse execution and meaningful Mission Control Center (MCC) interaction across communication latencies and can be

The amblyopic eye in subjects with anisometropia show increased saccadic latency in the delayed saccade task

PubMed Central

Perdziak, Maciej; Witkowska, Dagmara; Gryncewicz, Wojciech; Przekoracka-Krawczyk, Anna; Ober, Jan

2014-01-01

The term amblyopia is used to describe reduced visual function in one eye (or both eyes, though not so often) which cannot be fully improved by refractive correction and explained by the organic cause observed during regular eye examination. Amblyopia is associated with abnormal visual experience (e.g., anisometropia) during infancy or early childhood. Several studies have shown prolongation of saccadic latency time in amblyopic eye. In our opinion, study of saccadic latency in the context of central vision deficits assessment, should be based on central retina stimulation. For this reason, we proposed saccade delayed task. It requires inhibitory processing for maintaining fixation on the central target until it disappears—what constitutes the GO signal for saccade. The experiment consisted of 100 trials for each eye and was performed under two viewing conditions: monocular amblyopic/non-dominant eye and monocular dominant eye. We examined saccadic latency in 16 subjects (mean age 30 ± 11 years) with anisometropic amblyopia (two subjects had also microtropia) and in 17 control subjects (mean age 28 ± 8 years). Participants were instructed to look at central (fixation) target and when it disappears, to make the saccade toward the periphery (10°) as fast as possible, either left or the right target. The study results have proved the significant difference in saccadic latency between the amblyopic (mean 262 ± 48 ms) and dominant (mean 237 ± 45 ms) eye, in anisometropic group. In the control group, the saccadic latency for dominant (mean 226 ± 32 ms) and non-dominant (mean 230 ± 29 ms) eye was not significantly different. By the use of LATER (Linear Approach to the Threshold with Ergodic Rate) decision model we interpret our findings as a decrease in accumulation of visual information acquired by means of central retina in subjects with anisometropic amblyopia. PMID:25352790

Modulation of amplitude and latency of motor evoked potential by direction of transcranial magnetic stimulation

NASA Astrophysics Data System (ADS)

Sato, Aya; Torii, Tetsuya; Iwahashi, Masakuni; Itoh, Yuji; Iramina, Keiji

2014-05-01

The present study analyzed the effects of monophasic magnetic stimulation to the motor cortex. The effects of magnetic stimulation were evaluated by analyzing the motor evoked potentials (MEPs). The amplitude and latency of MEPs on the abductor pollicis brevis muscle were used to evaluate the effects of repetitive magnetic stimulation. A figure eight-shaped flat coil was used to stimulate the region over the primary motor cortex. The intensity of magnetic stimulation was 120% of the resting motor threshold, and the frequency of magnetic stimulation was 0.1 Hz. In addition, the direction of the current in the brain was posterior-anterior (PA) or anterior-posterior (AP). The latency of MEP was compared with PA and AP on initial magnetic stimulation. The results demonstrated that a stimulus in the AP direction increased the latency of the MEP by approximately 2.5 ms. MEP amplitude was also compared with PA and AP during 60 magnetic stimulations. The results showed that a stimulus in the PA direction gradually increased the amplitude of the MEP. However, a stimulus in the AP direction did not modulate the MEP amplitude. The average MEP amplitude induced from every 10 magnetic pulses was normalized by the average amplitude of the first 10 stimuli. These results demonstrated that the normalized MEP amplitude increased up to approximately 150%. In terms of pyramidal neuron indirect waves (I waves), magnetic stimulation inducing current flowing backward to the anterior preferentially elicited an I1 wave, and current flowing forward to the posterior elicited an I3 wave. It has been reported that the latency of the I3 wave is approximately 2.5 ms longer than the I1 wave elicitation, so the resulting difference in latency may be caused by this phenomenon. It has also been reported that there is no alteration of MEP amplitude at a frequency of 0.1 Hz. However, this study suggested that the modulation of MEP amplitude depends on stimulation strength and stimulation direction.

Reduced Short- and Long-Latency Afferent Inhibition Following Acute Muscle Pain: A Potential Role in the Recovery of Motor Output.

PubMed

Burns, Emma; Chipchase, Lucinda Sian; Schabrun, Siobhan May

2016-02-13

. Corticomotor output is reduced in response to acute muscle pain, yet the mechanisms that underpin this effect remain unclear. Here the authors investigate the effect of acute muscle pain on short-latency afferent inhibition, long-latency afferent inhibition, and long-interval intra-cortical inhibition to determine whether these mechanisms could plausibly contribute to reduced motor output in pain. . Observational same subject pre-post test design. . Neurophysiology research laboratory. . Healthy, right-handed human volunteers (n = 22, 9 male; mean age ± standard deviation, 22.6 ± 7.8 years). . Transcranial magnetic stimulation was used to assess corticomotor output, short-latency afferent inhibition, long-latency afferent inhibition, and long-interval intra-cortical inhibition before, during, immediately after, and 15 minutes after hypertonic saline infusion into right first dorsal interosseous muscle. Pain intensity and quality were recorded using an 11-point numerical rating scale and the McGill Pain Questionnaire. . Compared with baseline, corticomotor output was reduced at all time points (p = 0.001). Short-latency afferent inhibition was reduced immediately after (p = 0.039), and long-latency afferent inhibition 15 minutes after (p = 0.035), the resolution of pain. Long-interval intra-cortical inhibition was unchanged at any time point (p = 0.36). . These findings suggest short- and long-latency afferent inhibition, mechanisms thought to reflect the integration of sensory information with motor output at the cortex, are reduced following acute muscle pain. Although the functional relevance is unclear, the authors hypothesize a reduction in these mechanisms may contribute to the restoration of normal motor output after an episode of acute muscle pain. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Low-Latency Telerobotic Sample Return and Biomolecular Sequencing for Deep Space Gateway

NASA Astrophysics Data System (ADS)

Lupisella, M.; Bleacher, J.; Lewis, R.; Dworkin, J.; Wright, M.; Burton, A.; Rubins, K.; Wallace, S.; Stahl, S.; John, K.; Archer, D.; Niles, P.; Regberg, A.; Smith, D.; Race, M.; Chiu, C.; Russell, J.; Rampe, E.; Bywaters, K.

2018-02-01

Low-latency telerobotics, crew-assisted sample return, and biomolecular sequencing can be used to acquire and analyze lunar farside and/or Apollo landing site samples. Sequencing can also be used to monitor and study Deep Space Gateway environment and crew health.

Correlation analysis of the long latency auditory evoked potential N2 and cognitive P3 with the level of lead poisoning in children

PubMed Central

Alvarenga, Kátia de Freitas; Alvarez Bernardez-Braga, Gabriela Rosito; Zucki, Fernanda; Duarte, Josilene Luciene; Lopes, Andrea Cintra; Feniman, Mariza Ribeiro

2013-01-01

Summary Introduction: The effects of lead on children's health have been widely studied. Aim: To analyze the correlation between the long latency auditory evoked potential N2 and cognitive P3 with the level of lead poisoning in Brazilian children. Methods: This retrospective study evaluated 20 children ranging in age from 7 to 14 years at the time of audiological and electrophysiological evaluations. We performed periodic surveys of the lead concentration in the blood and basic audiological evaluations. Furthermore, we studied the auditory evoked potential long latency N2 and cognitive P3 by analyzing the absolute latency of the N2 and P3 potentials and the P3 amplitude recorded at Cz. At the time of audiological and electrophysiological evaluations, the average concentration of lead in the blood was less than 10 ug/dL. Results: In conventional audiologic evaluations, all children had hearing thresholds below 20 dBHL for the frequencies tested and normal tympanometry findings; the auditory evoked potential long latency N2 and cognitive P3 were present in 95% of children. No significant correlations were found between the blood lead concentration and latency (p = 0.821) or amplitude (p = 0.411) of the P3 potential. However, the latency of the N2 potential increased with the concentration of lead in the blood, with a significant correlation (p = 0.030). Conclusion: Among Brazilian children with low lead exposure, a significant correlation was found between blood lead levels and the average latency of the auditory evoked potential long latency N2; however, a significant correlation was not observed for the amplitude and latency of the cognitive potential P3. PMID:25991992

Patterned light flash evoked short latency activity in the visual system of visually normal and in amblyopic subjects.

PubMed

Sjöström, A; Abrahamsson, M

1994-04-01

In a previous experimental study on anaesthetized cat it was shown that a short latency (35-40 ms) cortical potential changed polarity due to the presence or absence of a pattern in the flash stimulus. The results suggested one pathway of neuronal activation in the cortex to a pattern that was within the level of resolution and another to patterns that were not. It was implied that a similar difference in impulse transmission to pattern and non-pattern stimuli may be recorded in humans. The present paper describes recordings of the short-latency visual evoked response to varying light flash checkerboard pattern stimuli of high intensity in visually normal and amblyopic children and adults. When stimulating the normal eye a visual evoked response potential with a peak latency between 35 to 40 ms showed a polarity change to patterned compared to non-patterned stimulation. The visual evoked response resolution limit could be correlated to a visual acuity of 0.5 and below. In amblyopic eyes the shift in polarity was recorded at the acuity limit level. The latency of the pattern depending potential was increased in patients with amblyopia compared to normal, but not directly related to amblyopic degree. It is concluded that the short latency, visual evoked response that mainly represents the retino-geniculo-cortical activation may be used to estimate visual resolution below 0.5 in acuity level.(ABSTRACT TRUNCATED AT 250 WORDS)

Autophagy Genes Enhance Murine Gammaherpesvirus 68 Reactivation From Latency by Preventing Virus-induced Systemic Inflammation

PubMed Central

Park, Sunmin; Buck, Michael D.; Desai, Chandni; Zhang, Xin; Loginicheva, Ekaterina; Martinez, Jennifer; Freeman, Michael L.; Saitoh, Tatsuya; Akira, Shizuo; Guan, Jun-Lin; He, You-Wen; Blackman, Marcia A.; Handley, Scott A.; Levine, Beth; Green, Douglas R.; Reese, Tiffany A.; Artyomov, Maxim N.; Virgin, Herbert W.

2016-01-01

SUMMARY Host genes that regulate systemic inflammation upon chronic viral infection are incompletely understood. Murine γ-herpesvirus 68 (MHV68) infection is characterized by latency in macrophages, and reactivation is inhibited by Interferon-γ (IFN-γ). Using a Lysozyme-M-cre (LysMcre) expression system, we show that deletion of autophagy-related (Atg) genes Fip200, beclin 1, Atg14, Atg16L1, Atg7, Atg3, and Atg5, in the myeloid compartment, inhibited MHV68 reactivation in macrophages. Atg5-deficiency did not alter reactivation from B cells, and effects on reactivation from macrophages were not explained by alterations in productive viral replication or the establishment of latency. Rather, chronic MHV68 infection triggered increased systemic inflammation, increased T cell production of IFN-γ and an IFN-γ-induced transcriptional signature in macrophages from Atg gene-deficient mice. The Atg5-related reactivation defect was partially reversed by neutralization of IFN-γ. Thus Atg genes in myeloid cells dampen virus-induced systemic inflammation, creating an environment that fosters efficient MHV68 reactivation from latency. PMID:26764599

From Motion to Photons in 80 Microseconds: Towards Minimal Latency for Virtual and Augmented Reality.

PubMed

Lincoln, Peter; Blate, Alex; Singh, Montek; Whitted, Turner; State, Andrei; Lastra, Anselmo; Fuchs, Henry

2016-04-01

We describe an augmented reality, optical see-through display based on a DMD chip with an extremely fast (16 kHz) binary update rate. We combine the techniques of post-rendering 2-D offsets and just-in-time tracking updates with a novel modulation technique for turning binary pixels into perceived gray scale. These processing elements, implemented in an FPGA, are physically mounted along with the optical display elements in a head tracked rig through which users view synthetic imagery superimposed on their real environment. The combination of mechanical tracking at near-zero latency with reconfigurable display processing has given us a measured average of 80 µs of end-to-end latency (from head motion to change in photons from the display) and also a versatile test platform for extremely-low-latency display systems. We have used it to examine the trade-offs between image quality and cost (i.e. power and logical complexity) and have found that quality can be maintained with a fairly simple display modulation scheme.

Evaluation of Hearing in Children with Autism by Using TEOAE and ABR

ERIC Educational Resources Information Center

Tas, Abdullah; Yagiz, Recep; Tas, Memduha; Esme, Meral; Uzun, Cem; Karasalihoglu, Ahmet Rifat

2007-01-01

Assessment of auditory abilities is important in the diagnosis and treatment of children with autism. The aim was to evaluate hearing objectively by using transient evoked otoacoustic emission (TEOAE) and auditory brainstem response (ABR). Tests were performed on 30 children with autism and 15 typically developing children, following otomicroscopy…

The search for instantaneous vection: An oscillating visual prime reduces vection onset latency.

PubMed

Palmisano, Stephen; Riecke, Bernhard E

2018-01-01

Typically it takes up to 10 seconds or more to induce a visual illusion of self-motion ("vection"). However, for this vection to be most useful in virtual reality and vehicle simulation, it needs to be induced quickly, if not immediately. This study examined whether vection onset latency could be reduced towards zero using visual display manipulations alone. In the main experiments, visual self-motion simulations were presented to observers via either a large external display or a head-mounted display (HMD). Priming observers with visually simulated viewpoint oscillation for just ten seconds before the main self-motion display was found to markedly reduce vection onset latencies (and also increase ratings of vection strength) in both experiments. As in earlier studies, incorporating this simulated viewpoint oscillation into the self-motion displays themselves was also found to improve vection. Average onset latencies were reduced from 8-9s in the no oscillating control condition to as little as 4.6 s (for external displays) or 1.7 s (for HMDs) in the combined oscillation condition (when both the visual prime and the main self-motion display were oscillating). As these display manipulations did not appear to increase the likelihood or severity of motion sickness in the current study, they could possibly be used to enhance computer generated simulation experiences and training in the future, at no additional cost.

The search for instantaneous vection: An oscillating visual prime reduces vection onset latency

PubMed Central

Riecke, Bernhard E.

2018-01-01

Typically it takes up to 10 seconds or more to induce a visual illusion of self-motion (“vection”). However, for this vection to be most useful in virtual reality and vehicle simulation, it needs to be induced quickly, if not immediately. This study examined whether vection onset latency could be reduced towards zero using visual display manipulations alone. In the main experiments, visual self-motion simulations were presented to observers via either a large external display or a head-mounted display (HMD). Priming observers with visually simulated viewpoint oscillation for just ten seconds before the main self-motion display was found to markedly reduce vection onset latencies (and also increase ratings of vection strength) in both experiments. As in earlier studies, incorporating this simulated viewpoint oscillation into the self-motion displays themselves was also found to improve vection. Average onset latencies were reduced from 8-9s in the no oscillating control condition to as little as 4.6 s (for external displays) or 1.7 s (for HMDs) in the combined oscillation condition (when both the visual prime and the main self-motion display were oscillating). As these display manipulations did not appear to increase the likelihood or severity of motion sickness in the current study, they could possibly be used to enhance computer generated simulation experiences and training in the future, at no additional cost. PMID:29791445

An Investigation on the Role of Spike Latency in an Artificial Olfactory System

PubMed Central

Martinelli, Eugenio; Polese, Davide; Dini, Francesca; Paolesse, Roberto; Filippini, Daniel; Lundström, Ingemar; Di Natale, Corrado

2011-01-01

Experimental studies have shown that the reactions to external stimuli may appear only few hundreds of milliseconds after the physical interaction of the stimulus with the proper receptor. This behavior suggests that neurons transmit the largest meaningful part of their signal in the first spikes, and than that the spike latency is a good descriptor of the information content in biological neural networks. In this paper this property has been investigated in an artificial sensorial system where a single layer of spiking neurons is trained with the data generated by an artificial olfactory platform based on a large array of chemical sensors. The capability to discriminate between distinct chemicals and mixtures of them was studied with spiking neural networks endowed with and without lateral inhibitions and considering as output feature of the network both the spikes latency and the average firing rate. Results show that the average firing rate of the output spikes sequences shows the best separation among the experienced vapors, however the latency code is able in a shorter time to correctly discriminate all the tested volatile compounds. This behavior is qualitatively similar to those recently found in natural olfaction, and noteworthy it provides practical suggestions to tail the measurement conditions of artificial olfactory systems defining for each specific case a proper measurement time. PMID:22194721

Distraction rate and latency: factors in the outcome of paediatric maxillary distraction.

PubMed

Higuera, Stephen; Cole, Patrick; Stephenson, J B; Hollier, Larry

2009-12-01

Over 50 years ago, current tenets of distraction osteogenesis were developed through work on the lower extremity; however, the application of these tenets in the paediatric craniofacial skeleton remains questionable. Prompted by recent concern that traditional aspects of distraction may be either outdated or wholly inapplicable to the paediatric maxilla, we retrospectively evaluated maxillary distraction protocol using a 24-h latency period in conjunction with a distraction rate of 2mm/day. Following maxillary advancement via a distraction protocol consisting of a 24-h latency period and a distraction rate of 2mm/day, seven consecutive paediatric cases were evaluated. Standard profile photos and cephalometric films taken preoperatively, at device removal and at 1-year follow-up were compared. With the sella as the point of registration, pre- and post-distraction films were superimposed on the sella-nasion plane. Sella-nasion-subspinale, the angle of convexity, the distance from incisal edges to the y-axis, and angulation of the upper incisor to the sella-nasion plane were analysed to evaluate hard-tissue changes. Patient age ranged from 3 to 14 years (mean=7.43 years). Maxillary distraction length averaged 11 mm (range=10-12 mm). Interval from device application to removal averaged 98 days (range=75-180 days). The interval of the active distraction ranged from 11 to 65 days (mean=24 days). From distraction completion to device removal averaged 85 days (range=60-150). Follow-up intervals ranged from 52 to 24 months (mean=34 months). All patients demonstrated substantial clinical advancement of the maxilla with correction of midfacial deficiencies. A single patient developed mild cellulitis at one skin-device interface; no other complications were noted. Cephalometric and clinical evaluations at 1 year post-distraction demonstrated stable results, and parental satisfaction was qualitatively high. The surgical dogma of lower-extremity distraction osteogenesis is not

Flash Memory Reliability: Read, Program, and Erase Latency Versus Endurance Cycling

NASA Technical Reports Server (NTRS)

Heidecker, Jason

2010-01-01

This report documents the efforts and results of the fiscal year (FY) 2010 NASA Electronic Parts and Packaging Program (NEPP) task for nonvolatile memory (NVM) reliability. This year's focus was to measure latency (read, program, and erase) of NAND Flash memories and determine how these parameters drift with erase/program/read endurance cycling.

Effects of analog and digital filtering on auditory middle latency responses in adults and young children.

PubMed

Suzuki, T; Hirabayashi, M; Kobayashi, K

1984-01-01

Effects of analog high pass (HP) filtering were compared with those of zero phase-shift digital filtering on the auditory middle latency responses (MLR) from nine adults and 16 young children with normal hearing. Analog HP filtering exerted several prominent effects on the MLR waveforms in both adults and young children, such as suppression of Po (ABR), enhancement of Nb, enhancement or emergence of Pb, and latency decrements for Pa and the later components. Analog HP filtering at 20 Hz produced more pronounced waveform distortions in the responses from young children than from adults. Much greater latency decrements for Pa and Nb were observed for young children than for adults in the analog HP-filtered responses at 20 Hz. A large positive peak (Pb) emerged at about 65 ms after the stimulus onset. From these results, the use of digital HP filtering at 20 Hz is strongly recommended for obtaining unbiased and stable MLR in young children.

Sex-Related Cochlear Impairment in Cigarette Smokers

PubMed Central

Lisowska, Grażyna; Jochem, Jerzy; Gierlotka, Agata; Misiołek, Maciej; Ścierski, Wojciech

2017-01-01

Background A number of studies have documented the influence of cigarette smoking on hearing. However, the association between sex and hearing impairment in smokers as measured by otoacoustic emissions (OAEs) has not been clearly established. The aim of this study was to analyze sex-specific effects of smoking on hearing via conventional and ultra-high-frequency pure tone audiometry (PTA), and OAEs, specifically spontaneous OAEs, click-evoked OAEs, and distortion-product OAEs. Material/Methods The study included 84 healthy volunteers aged 25–45 years (mean 34), among them 46 women (25 non-smokers and 21 smokers) and 38 men (16 non-smokers and 22 smokers). The protocol of the study included otoscopic examination, tympanometry, low-, moderate-, and ultra-high-frequency PTA, evaluation of spontaneous click-evoked (CEAOEs) and distortion-product otoacoustic emissions (DPOAEs), assessment of the DP-grams for 2f1-f2 (f1 from 977 to5 164 Hz), and input/output function at L2 primary tone level of 40–70 dB SPL. Results Smokers and non-smokers did not differ significantly in terms of their hearing thresholds assessed with tone audiometry. Male smokers presented with significantly lower levels of CEAOEs and DPOAEs than both male non-smokers and female smokers. Conclusions Smoking does not modulate a hearing threshold determined with PTA at low, moderate, and ultra-high frequencies, but causes a significant decrease in OAE levels. This effect was observed only in males, which implies that they are more susceptible to smoking-induced hearing impairment. Sex-specific differences in otoacoustic emissions level may reflect influences of genetic, hormonal, behavioral, and/or environmental factors. PMID:28110343

Low latency and persistent data storage

DOEpatents

Fitch, Blake G; Franceschini, Michele M; Jagmohan, Ashish; Takken, Todd E

2014-02-18

Persistent data storage is provided by a method that includes receiving a low latency store command that includes write data. The write data is written to a first memory device that is implemented by a nonvolatile solid-state memory technology characterized by a first access speed. It is acknowledged that the write data has been successfully written to the first memory device. The write data is written to a second memory device that is implemented by a volatile memory technology. At least a portion of the data in the first memory device is written to a third memory device when a predetermined amount of data has been accumulated in the first memory device. The third memory device is implemented by a nonvolatile solid-state memory technology characterized by a second access speed that is slower than the first access speed.

Statistical learning methods for aero-optic wavefront prediction and adaptive-optic latency compensation

NASA Astrophysics Data System (ADS)

Burns, W. Robert

Since the early 1970's research in airborne laser systems has been the subject of continued interest. Airborne laser applications depend on being able to propagate a near diffraction-limited laser beam from an airborne platform. Turbulent air flowing over the aircraft produces density fluctuations through which the beam must propagate. Because the index of refraction of the air is directly related to the density, the turbulent flow imposes aberrations on the beam passing through it. This problem is referred to as Aero-Optics. Aero-Optics is recognized as a major technical issue that needs to be solved before airborne optical systems can become routinely fielded. This dissertation research specifically addresses an approach to mitigating the deleterious effects imposed on an airborne optical system by aero-optics. A promising technology is adaptive optics: a feedback control method that measures optical aberrations and imprints the conjugate aberrations onto an outgoing beam. The challenge is that it is a computationally-difficult problem, since aero-optic disturbances are on the order of kilohertz for practical applications. High control loop frequencies and high disturbance frequencies mean that adaptive-optic systems are sensitive to latency in sensors, mirrors, amplifiers, and computation. These latencies build up to result in a dramatic reduction in the system's effective bandwidth. This work presents two variations of an algorithm that uses model reduction and data-driven predictors to estimate the evolution of measured wavefronts over a short temporal horizon and thus compensate for feedback latency. The efficacy of the two methods are compared in this research, and evaluated against similar algorithms that have been previously developed. The best version achieved over 75% disturbance rejection in simulation in the most optically active flow region in the wake of a turret, considerably outperforming conventional approaches. The algorithm is shown to be

Area/latency optimized early output asynchronous full adders and relative-timed ripple carry adders.

PubMed

Balasubramanian, P; Yamashita, S

2016-01-01

This article presents two area/latency optimized gate level asynchronous full adder designs which correspond to early output logic. The proposed full adders are constructed using the delay-insensitive dual-rail code and adhere to the four-phase return-to-zero handshaking. For an asynchronous ripple carry adder (RCA) constructed using the proposed early output full adders, the relative-timing assumption becomes necessary and the inherent advantages of the relative-timed RCA are: (1) computation with valid inputs, i.e., forward latency is data-dependent, and (2) computation with spacer inputs involves a bare minimum constant reverse latency of just one full adder delay, thus resulting in the optimal cycle time. With respect to different 32-bit RCA implementations, and in comparison with the optimized strong-indication, weak-indication, and early output full adder designs, one of the proposed early output full adders achieves respective reductions in latency by 67.8, 12.3 and 6.1 %, while the other proposed early output full adder achieves corresponding reductions in area by 32.6, 24.6 and 6.9 %, with practically no power penalty. Further, the proposed early output full adders based asynchronous RCAs enable minimum reductions in cycle time by 83.4, 15, and 8.8 % when considering carry-propagation over the entire RCA width of 32-bits, and maximum reductions in cycle time by 97.5, 27.4, and 22.4 % for the consideration of a typical carry chain length of 4 full adder stages, when compared to the least of the cycle time estimates of various strong-indication, weak-indication, and early output asynchronous RCAs of similar size. All the asynchronous full adders and RCAs were realized using standard cells in a semi-custom design fashion based on a 32/28 nm CMOS process technology.

Human short-latency ocular vergence responses produced by interocular velocity differences

PubMed Central

Sheliga, B. M.; Quaia, C.; FitzGibbon, E. J.; Cumming, B. G.

2016-01-01

We studied human short-latency vergence eye movements to a novel stimulus that produces interocular velocity differences without a changing disparity signal. Sinusoidal luminance gratings moved in opposite directions (left vs. right; up vs. down) in the two eyes. The grating seen by each eye underwent ¼-wavelength shifts with each image update. This arrangement eliminated changing disparity cues, since the phase difference between the eyes alternated between 0° and 180°. We nevertheless observed robust short-latency vergence responses (VRs), whose sign was consistent with the interocular velocity differences (IOVDs), indicating that the IOVD cue in isolation can evoke short-latency VRs. The IOVD cue was effective only when the images seen by the two eyes overlapped in space. We observed equally robust VRs for opposite horizontal motions (left in one eye, right in the other) and opposite vertical motions (up in one eye, down in the other). Whereas the former are naturally generated by objects moving in depth, the latter are not part of our normal experience. To our knowledge, this is the first demonstration of a behavioral consequence of vertical IOVD. This may reflect the fact that some neurons in area MT are sensitive to these motion signals (Czuba, Huk, Cormack, & Kohn, 2014). VRs were the strongest for spatial frequencies in the range of 0.35–1 c/°, much higher than the optimal spatial frequencies for evoking ocular-following responses observed during frontoparallel motion. This suggests that the two motion signals are detected by different neuronal populations. We also produced IOVD using moving uncorrelated one-dimensional white-noise stimuli. In this case the most effective stimuli have low speed, as predicted if the drive originates in neurons tuned to high spatial frequencies (Sheliga, Quaia, FitzGibbon, & Cumming, 2016). PMID:27548089

Influence of Herpes Simplex Virus Latency-Associated Transcript (LAT) on the Distribution of Latently Infected Neurons

DTIC Science & Technology

2007-03-20

part of my life, who knows more about herpesviruses than any 8-year-old should, for making me tea and snacks when I was studying or writing, for...of latency (2, 13, 36, 45, 76, 77, 81). However, HSV-2 LAT has not been shown to inhibit apoptosis of neuronal cells. HSV has several anti ...apoptotic genes, including ICP27, ICP22, US3, US5, ICP4, and HSV-1 LAT (4). Only LAT is expressed during latency, suggesting that its anti -apoptotic

Reducing the PAPR in FBMC-OQAM systems with low-latency trellis-based SLM technique

NASA Astrophysics Data System (ADS)

Bulusu, S. S. Krishna Chaitanya; Shaiek, Hmaied; Roviras, Daniel

2016-12-01

Filter-bank multi-carrier (FBMC) modulations, and more specifically FBMC-offset quadrature amplitude modulation (OQAM), are seen as an interesting alternative to orthogonal frequency division multiplexing (OFDM) for the 5th generation radio access technology. In this paper, we investigate the problem of peak-to-average power ratio (PAPR) reduction for FBMC-OQAM signals. Recently, it has been shown that FBMC-OQAM with trellis-based selected mapping (TSLM) scheme not only is superior to any scheme based on symbol-by-symbol approach but also outperforms that of the OFDM with classical SLM scheme. This paper is an extension of that work, where we analyze the TSLM in terms of computational complexity, required hardware memory, and latency issues. We have proposed an improvement to the TSLM, which requires very less hardware memory, compared to the originally proposed TSLM, and also have low latency. Additionally, the impact of the time duration of partial PAPR on the performance of TSLM is studied, and its lower bound has been identified by proposing a suitable time duration. Also, a thorough and fair comparison of performance has been done with an existing trellis-based scheme proposed in literature. The simulation results show that the proposed low-latency TSLM yields better PAPR reduction performance with relatively less hardware memory requirements.

Influence of fatigue and velocity on the latency and recruitment order of scapular muscles.

PubMed

Mendez-Rebolledo, Guillermo; Gatica-Rojas, Valeska; Guzman-Muñoz, Eduardo; Martinez-Valdes, Eduardo; Guzman-Venegas, Rodrigo; Berral de la Rosa, Francisco Jose

2018-07-01

To determine the influence of velocity and fatigue on scapular muscle activation latency and recruitment order during a voluntary arm raise task, in healthy individuals. Cross-sectional study. University laboratory. Twenty three male adults per group (high-velocity and low-velocity). Onset latency of scapular muscles [Anterior deltoid (AD), lower trapezius (LT), middle trapezius (MT), upper trapezius (UT), and serratus anterior (SA)] was assessed by surface electromyography. The participants were assigned to one of two groups: low-velocity or high-velocity. Both groups performed a voluntary arm raise task in the scapular plane under two conditions: no-fatigue and fatigue. The UT showed early activation (p < 0.01) in the fatigue condition when performing the arm raise task at a high velocity. At a low velocity and with no muscular fatigue, the recruitment order was MT, LT, SA, AD, and UT. However, the recruitment order changed in the high-velocity with muscular fatigue condition, since the recruitment order was UT, AD, SA, LT, and MT. The simultaneous presence of fatigue and high-velocity in an arm raise task is associated with a decrease in the UT activation latency and a modification of the recruitment order of scapular muscles. Copyright © 2018 Elsevier Ltd. All rights reserved.

Leading, but not trailing, primes influence temporal order perception: further evidence for an attentional account of perceptual latency priming.

PubMed

Scharlau, Ingrid

2002-11-01

Presenting a masked prime leading a target influences the perceived onset of the masking target (perceptual latency priming; Scharlau & Neumann, in press). This priming effect is explained by the asynchronous updating model (Neumann, 1982; Scharlau & Neumann, in press): The prime initiates attentional allocation toward its location, which renders a trailing target at the same place consciously available earlier. In three experiments, this perceptual latency priming by leading primes was examined jointly with the effects of trailing primes in order to compare the explanation of the asynchronous updating model with the onset-averaging and the P-center hypotheses. Experiment 1 showed that an attended, as well as an unattended, prime leads to perceptual latency priming. In addition, a large effect of trailing primes on the onset of a target was found. As Experiment 2 demonstrated, this effect is quite robust, although smaller than that of a leading prime. In Experiment 3, masked primes were used. Under these conditions, no influence of trailing primes could be found, whereas perceptual latency priming persisted. Thus, a nonattentional explanation for the effect of trailing primes seems likely.

Automated cortical auditory evoked potentials threshold estimation in neonates.

PubMed

Oliveira, Lilian Sanches; Didoné, Dayane Domeneghini; Durante, Alessandra Spada

2018-02-02

The evaluation of Cortical Auditory Evoked Potential has been the focus of scientific studies in infants. Some authors have reported that automated response detection is effective in exploring these potentials in infants, but few have reported their efficacy in the search for thresholds. To analyze the latency, amplitude and thresholds of Cortical Auditory Evoked Potential using an automatic response detection device in a neonatal population. This is a cross-sectional, observational study. Cortical Auditory Evoked Potentials were recorded in response to pure-tone stimuli of the frequencies 500, 1000, 2000 and 4000Hz presented in an intensity range between 0 and 80dB HL using a single channel recording. P1 was performed in an exclusively automated fashion, using Hotelling's T 2 statistical test. The latency and amplitude were obtained manually by three examiners. The study comprised 39 neonates up to 28 days old of both sexes with presence of otoacoustic emissions and no risk factors for hearing loss. With the protocol used, Cortical Auditory Evoked Potential responses were detected in all subjects at high intensity and thresholds. The mean thresholds were 24.8±10.4dB NA, 25±9.0dB NA, 28±7.8dB NA and 29.4±6.6dB HL for 500, 1000, 2000 and 4000Hz, respectively. Reliable responses were obtained in the assessment of cortical auditory potentials in the neonates assessed with a device for automatic response detection. Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

A low-latency high-port count optical switch with optical delay line buffering for disaggregated data centers

NASA Astrophysics Data System (ADS)

Moralis-Pegios, M.; Terzenidis, N.; Mourgias-Alexandris, G.; Vyrsokinos, K.; Pleros, N.

2018-02-01

Disaggregated Data Centers (DCs) have emerged as a powerful architectural framework towards increasing resource utilization and system power efficiency, requiring, however, a networking infrastructure that can ensure low-latency and high-bandwidth connectivity between a high-number of interconnected nodes. This reality has been the driving force towards high-port count and low-latency optical switching platforms, with recent efforts concluding that the use of distributed control architectures as offered by Broadcast-and-Select (BS) layouts can lead to sub-μsec latencies. However, almost all high-port count optical switch designs proposed so far rely either on electronic buffering and associated SerDes circuitry for resolving contention or on buffer-less designs with packet drop and re-transmit procedures, unavoidably increasing latency or limiting throughput. In this article, we demonstrate a 256x256 optical switch architecture for disaggregated DCs that employs small-size optical delay line buffering in a distributed control scheme, exploiting FPGA-based header processing over a hybrid BS/Wavelength routing topology that is implemented by a 16x16 BS design and a 16x16 AWGR. Simulation-based performance analysis reveals that even the use of a 2- packet optical buffer can yield <620nsec latency with >85% throughput for up to 100% loads. The switch has been experimentally validated with 10Gb/s optical data packets using 1:16 optical splitting and a SOA-MZI wavelength converter (WC) along with fiber delay lines for the 2-packet buffer implementation at every BS outgoing port, followed by an additional SOA-MZI tunable WC and the 16x16 AWGR. Error-free performance in all different switch input/output combinations has been obtained with a power penalty of <2.5dB.

Method of data communications with reduced latency

DOEpatents

Blocksome, Michael A; Parker, Jeffrey J

2013-11-05

Data communications with reduced latency, including: writing, by a producer, a descriptor and message data into at least two descriptor slots of a descriptor buffer, the descriptor buffer comprising allocated computer memory segmented into descriptor slots, each descriptor slot having a fixed size, the descriptor buffer having a header pointer that identifies a next descriptor slot to be processed by a DMA controller, the descriptor buffer having a tail pointer that identifies a descriptor slot for entry of a next descriptor in the descriptor buffer; recording, by the producer, in the descriptor a value signifying that message data has been written into descriptor slots; and setting, by the producer, in dependence upon the recorded value, a tail pointer to point to a next open descriptor slot.

Low-dose radiation from 18F-FDG PET does not increase cancer frequency or shorten latency but reduces kidney disease in cancer-prone Trp53+/- mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Kristina; Lemon, Jennifer A.; Phan, Nghi

There is considerable interest in the health effects associated with low-level radiation exposure from medical imaging procedures. Concerns in the medical community that increased radiation exposure from imaging procedures may increase cancer risk among patients are confounded by research showing that low-dose radiation exposure can extend lifespan by increasing the latency period of some types of cancer. The most commonly used radiopharmaceutical for positron emission tomography (PET) scans is 2-[ 18F] fluoro-2-deoxy-d-glucose ( 18F-FDG), which exposes tissue to a low-dose, mixed radiation quality: 634 keV β+ and 511 keV γ-rays. The goal of this research was to investigate how modificationmore » of cancer risk associated with exposure to low-dose ionising radiation in cancer-prone Trp53+/- mice is influenced by radiation quality from PET. At 7-8 weeks of age, Trp53+/- female mice were exposed to one of five treatments: 0 Gy, 10 mGy γ-rays, 10 mGy 18F-FDG, 4 Gy γ-rays, 10 mGy 18F-FDG + 4 Gy γ-rays (n > 185 per group). The large 4-Gy radiation dose significantly reduced the lifespan by shortening the latency period of cancer and significantly increasing the number of mice with malignancies, compared with unirradiated controls. The 10 mGy γ-rays and 10 mGy PET doses did not significantly modify the frequency or latency period of cancer relative to unirradiated mice. Similarly, the PET scan administered prior to a large 4-Gy dose did not significantly modify the latency or frequency of cancer relative to mice receiving a dose of only 4 Gy. The relative biological effectiveness of radiation quality from 18F-FDG, with respect to malignancy, is approximately 1. Furthermore, when non-cancer endpoints were studied, it was found that the 10-mGy PET group had a significant reduction in kidney lesions (P < 0.021), indicating that a higher absorbed dose (20 ± 0.13 mGy), relative to the whole-body average, which occurs in specific tissues, may not be detrimental.« less

Low-dose radiation from 18F-FDG PET does not increase cancer frequency or shorten latency but reduces kidney disease in cancer-prone Trp53+/- mice

DOE PAGES

Taylor, Kristina; Lemon, Jennifer A.; Phan, Nghi; ...

2014-05-28

There is considerable interest in the health effects associated with low-level radiation exposure from medical imaging procedures. Concerns in the medical community that increased radiation exposure from imaging procedures may increase cancer risk among patients are confounded by research showing that low-dose radiation exposure can extend lifespan by increasing the latency period of some types of cancer. The most commonly used radiopharmaceutical for positron emission tomography (PET) scans is 2-[ 18F] fluoro-2-deoxy-d-glucose ( 18F-FDG), which exposes tissue to a low-dose, mixed radiation quality: 634 keV β+ and 511 keV γ-rays. The goal of this research was to investigate how modificationmore » of cancer risk associated with exposure to low-dose ionising radiation in cancer-prone Trp53+/- mice is influenced by radiation quality from PET. At 7-8 weeks of age, Trp53+/- female mice were exposed to one of five treatments: 0 Gy, 10 mGy γ-rays, 10 mGy 18F-FDG, 4 Gy γ-rays, 10 mGy 18F-FDG + 4 Gy γ-rays (n > 185 per group). The large 4-Gy radiation dose significantly reduced the lifespan by shortening the latency period of cancer and significantly increasing the number of mice with malignancies, compared with unirradiated controls. The 10 mGy γ-rays and 10 mGy PET doses did not significantly modify the frequency or latency period of cancer relative to unirradiated mice. Similarly, the PET scan administered prior to a large 4-Gy dose did not significantly modify the latency or frequency of cancer relative to mice receiving a dose of only 4 Gy. The relative biological effectiveness of radiation quality from 18F-FDG, with respect to malignancy, is approximately 1. Furthermore, when non-cancer endpoints were studied, it was found that the 10-mGy PET group had a significant reduction in kidney lesions (P < 0.021), indicating that a higher absorbed dose (20 ± 0.13 mGy), relative to the whole-body average, which occurs in specific tissues, may not be detrimental.« less

Low latency and persistent data storage

DOEpatents

Fitch, Blake G; Franceschini, Michele M; Jagmohan, Ashish; Takken, Todd

2014-11-04

Persistent data storage is provided by a computer program product that includes computer program code configured for receiving a low latency store command that includes write data. The write data is written to a first memory device that is implemented by a nonvolatile solid-state memory technology characterized by a first access speed. It is acknowledged that the write data has been successfully written to the first memory device. The write data is written to a second memory device that is implemented by a volatile memory technology. At least a portion of the data in the first memory device is written to a third memory device when a predetermined amount of data has been accumulated in the first memory device. The third memory device is implemented by a nonvolatile solid-state memory technology characterized by a second access speed that is slower than the first access speed.

Human Space Exploration and Human Space Flight: Latency and the Cognitive Scale of the Universe

NASA Technical Reports Server (NTRS)

Lester, Dan; Thronson, Harley

2011-01-01

The role of telerobotics in space exploration as placing human cognition on other worlds is limited almost entirely by the speed of light, and the consequent communications latency that results from large distances. This latency is the time delay between the human brain at one end, and the telerobotic effector and sensor at the other end. While telerobotics and virtual presence is a technology that is rapidly becoming more sophisticated, with strong commercial interest on the Earth, this time delay, along with the neurological timescale of a human being, quantitatively defines the cognitive horizon for any locale in space. That is, how distant can an operator be from a robot and not be significantly impacted by latency? We explore that cognitive timescale of the universe, and consider the implications for telerobotics, human space flight, and participation by larger numbers of people in space exploration. We conclude that, with advanced telepresence, sophisticated robots could be operated with high cognition throughout a lunar hemisphere by astronauts within a station at an Earth-Moon Ll or L2 venue. Likewise, complex telerobotic servicing of satellites in geosynchronous orbit can be carried out from suitable terrestrial stations.

Improved UT1 Predictions through Low-Latency VLBI Observations