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Sample records for horizontal semicircular canal

  1. Changes in monkey horizontal semicircular canal afferent responses after spaceflight

    NASA Technical Reports Server (NTRS)

    Correia, M. J.; Perachio, A. A.; Dickman, J. D.; Kozlovskaia, I. B.; Sirota, M. G.; Iakushin, S. B.; Beloozerova, I. N.

    1992-01-01

    Extracellular responses from single horizontal semicircular canal afferents in two rhesus monkeys were studied after recovery from a 14-day biosatellite (Cosmos 2044) orbital spaceflight. On the 1st postflight day, the mean gain for 9 different horizontal canal afferents, tested using one or several different passive yaw rotation waveforms, was nearly twice that for 20 horizontal canal afferents similarly tested during preflight and postflight control studies. Adaptation of the afferent response to passive yaw rotation on the 1st postflight day was also greater. These results suggest that at least one component of the vestibular end organ (the semicircular canals) is transiently modified after exposure to 14 days of microgravity. It is unclear whether the changes are secondary to other effects of microgravity, such as calcium loss, or an adaptive response. If the response is adaptive, then this report is the first evidence that the response of the vestibular end organ may be modified (presumably by the central nervous system via efferent connections) after prolonged unusual vestibular stimulation. If this is the case, the sites of plasticity of vestibular responses may not be exclusively within central nervous system vestibular structures, as previously believed.

  2. The Semicircular Canal Microphonic

    NASA Technical Reports Server (NTRS)

    Rabbitt, R. D.; Boyle, R.; Highstein, S. M.; Dalton, Bonnie P. (Technical Monitor)

    2002-01-01

    Present experiments were designed to quantify the alternating current (AC) component of the semicircular canal microphonic for angular motion stimulation as a function of stimulus frequency and amplitude. The oyster toadfish, Opsanus tau, was used as the experimental model. Calibrated mechanical indentation of the horizontal canal duct was used as a stimulus to generate hair-cell and afferent responses reproducing those present during head rotation. Sensitivity to polarization of the endolymph DC voltage re: perilymph was also investigated. Modulation of endolymph voltage was recorded using conventional glass electrodes and lock-in amplification over the frequency range 0.2-80 Hz. Access to the endolymph for inserting voltage recording and current passing electrodes was obtained by sectioning the anterior canal at its apex and isolating the cut ends in air. For sinusoidal stimulation below approx.10 Hz, the horizontal semicircular canal AC microphonic was nearly independent of stimulus frequency and equal to approximately 4 microV per micron indent (equivalent to approx. 1 microV per deg/s). A saturating nonlinearity decreasing the microphonic gain was present for stimuli exceeding approx.3 micron indent (approx. 12 deg/s angular velocity). The phase was not sensitive to the saturating nonlinearity. The microphonic exhibited a resonance near 30Hz consistent with basolateral current hair cell resonance observed previously in voltage-clamp records from semicircular canal hair cells. The magnitude and phase of the microphonic exhibited sensitivity to endolymphatic polarization consistent with electro-chemical reversal of hair cell transduction currents.

  3. The Semicircular Canal Microphonic

    NASA Technical Reports Server (NTRS)

    Rabbitt, R. D.; Boyle, R.; Highstein, S. M.; Dalton, Bonnie P. (Technical Monitor)

    2002-01-01

    Present experiments were designed to quantify the alternating current (AC) component of the semicircular canal microphonic for angular motion stimulation as a function of stimulus frequency and amplitude. The oyster toadfish, Opsanus tau, was used as the experimental model. Calibrated mechanical indentation of the horizontal canal duct was used as a stimulus to generate hair-cell and afferent responses reproducing those present during head rotation. Sensitivity to polarization of the endolymph DC voltage re: perilymph was also investigated. Modulation of endolymph voltage was recorded using conventional glass electrodes and lock-in amplification over the frequency range 0.2-80 Hz. Access to the endolymph for inserting voltage recording and current passing electrodes was obtained by sectioning the anterior canal at its apex and isolating the cut ends in air. For sinusoidal stimulation below approx.10 Hz, the horizontal semicircular canal AC microphonic was nearly independent of stimulus frequency and equal to approximately 4 microV per micron indent (equivalent to approx. 1 microV per deg/s). A saturating nonlinearity decreasing the microphonic gain was present for stimuli exceeding approx.3 micron indent (approx. 12 deg/s angular velocity). The phase was not sensitive to the saturating nonlinearity. The microphonic exhibited a resonance near 30Hz consistent with basolateral current hair cell resonance observed previously in voltage-clamp records from semicircular canal hair cells. The magnitude and phase of the microphonic exhibited sensitivity to endolymphatic polarization consistent with electro-chemical reversal of hair cell transduction currents.

  4. Preserved otolith organ function in caspase-3 deficient mice with impaired horizontal semicircular canal function

    PubMed Central

    Armstrong, Patrick A; Wood, Scott J; Shimizu, Naoki; Kuster, Kael; Perachio, Adrian; Makishima, Tomoko

    2015-01-01

    Genetically engineered mice are valuable models for elucidation of auditory and vestibular pathology. Our goal was to establish a comprehensive vestibular function testing system in mice using: 1) horizontal angular vestibular-ocular reflex (hVOR) to evaluate semicircular canal function, and 2) otolith-ocular reflex (OOR) to evaluate otolith organ function, and to validate the system by characterizing mice with vestibular dysfunction. We used pseudo-off vertical axis rotation (pOVAR) to induce an otolith-only stimulus using a custom-made centrifuge. For the OOR, horizontal slow phase eye velocity (HEV) and vertical eye position (VEP) was evaluated as a function of acceleration. Using this system, we characterized hVOR and OOR in the caspase-3 (Casp3) mutant mice. Casp3 −/− mice had severely impaired hVOR gain, while Casp3 +/− mice had an intermediate response compared to WT mice. Evaluation of OOR revealed that at low to mid frequencies and stimulus intensity, Casp3 mutants and WT mice had similar responses. At higher frequencies and stimulus intensity, the Casp3 mutants displayed mildly reduced otolith organ related responses. These findings suggest that the Casp3 gene is important for the proper function of the semicircular canals but less important for the otolith organ function. PMID:25827332

  5. Adaptation of primate vestibuloocular reflex to altered peripheral vestibular inputs. I. Frequency-specific recovery of horizontal VOR after inactivation of the lateral semicircular canals

    NASA Technical Reports Server (NTRS)

    Angelaki, D. E.; Hess, B. J.; Arai, Y.; Suzuki, J.

    1996-01-01

    1. The adaptive plasticity of the vestibuloocular reflex (VOR) following a selective lesion of the peripheral vestibular organs was investigated in rhesus monkeys whose lateral semicircular canals were inactivated by plugging of the canal lumen in both ears. Gain and phase of horizontal, vertical, and torsional slow-phase eye velocity were determined from three-dimensional eye movement recordings obtained acutely after the plugging operation, as well as in regular intervals up to 10 mo later. 2. Acutely after plugging, horizontal VOR was minimal during yaw rotation with gains of < 0.1 at all frequencies. Horizontal VOR gain gradually increased over time, reaching gains of 0.4-0.5 for yaw oscillations at 1.1 Hz approximately 5 mo after lateral canal inactivation. This response recovery was strongly frequency dependent: horizontal VOR gains were largest at the highest frequency tested and progressively decreased for lower frequencies. Below approximately 0.1 Hz, no consistent horizontal VOR could be elicited even 10 mo after plugging. 3. The frequency-dependent changes in gain paralleled changes in horizontal VOR phase. Below approximately 0.1-0.05 Hz large phase leads were present, similarly as in semicircular canal primary afferents. Smaller phase leads were also present at higher frequencies, particularly at 1.1 Hz (the highest frequency tested). 4. Consistent with the afferent-like dynamics of the adapted horizontal VOR, per- and postrotatory horizontal responses to constant-velocity yaw rotations were short lasting. Time constants of the slow-phase eye velocity envelope of the horizontal postrotatory nystagmus were approximately 2 s. Nonetheless, a consistent horizontal optokinetic afternystagmus was evoked in plugged animals. 5. A torsional component that was absent in intact animals was consistently present during yaw rotation acutely after lateral canal inactivation and remained approximately constant thereafter. The frequency response characteristics of this

  6. Adaptation of primate vestibuloocular reflex to altered peripheral vestibular inputs. I. Frequency-specific recovery of horizontal VOR after inactivation of the lateral semicircular canals

    NASA Technical Reports Server (NTRS)

    Angelaki, D. E.; Hess, B. J.; Arai, Y.; Suzuki, J.

    1996-01-01

    1. The adaptive plasticity of the vestibuloocular reflex (VOR) following a selective lesion of the peripheral vestibular organs was investigated in rhesus monkeys whose lateral semicircular canals were inactivated by plugging of the canal lumen in both ears. Gain and phase of horizontal, vertical, and torsional slow-phase eye velocity were determined from three-dimensional eye movement recordings obtained acutely after the plugging operation, as well as in regular intervals up to 10 mo later. 2. Acutely after plugging, horizontal VOR was minimal during yaw rotation with gains of < 0.1 at all frequencies. Horizontal VOR gain gradually increased over time, reaching gains of 0.4-0.5 for yaw oscillations at 1.1 Hz approximately 5 mo after lateral canal inactivation. This response recovery was strongly frequency dependent: horizontal VOR gains were largest at the highest frequency tested and progressively decreased for lower frequencies. Below approximately 0.1 Hz, no consistent horizontal VOR could be elicited even 10 mo after plugging. 3. The frequency-dependent changes in gain paralleled changes in horizontal VOR phase. Below approximately 0.1-0.05 Hz large phase leads were present, similarly as in semicircular canal primary afferents. Smaller phase leads were also present at higher frequencies, particularly at 1.1 Hz (the highest frequency tested). 4. Consistent with the afferent-like dynamics of the adapted horizontal VOR, per- and postrotatory horizontal responses to constant-velocity yaw rotations were short lasting. Time constants of the slow-phase eye velocity envelope of the horizontal postrotatory nystagmus were approximately 2 s. Nonetheless, a consistent horizontal optokinetic afternystagmus was evoked in plugged animals. 5. A torsional component that was absent in intact animals was consistently present during yaw rotation acutely after lateral canal inactivation and remained approximately constant thereafter. The frequency response characteristics of this

  7. Planer orientation of the bilateral semicircular canals in dizzy patients.

    PubMed

    Aoki, Sachiko; Takei, Yasuhiko; Suzuki, Kazufumi; Masukawa, Ai; Arai, Yasuko

    2012-10-01

    Recent development of 3-dimensional analysis of eye movement enabled to detect the eye rotation axis, which is used to determine the responsible semicircular canal(s) in dizzy patients. Therefore, the knowledge of anatomical orientation of bilateral semicircular canals is essential, as all 6 canals influence the eye movements. Employing the new head coordinate system suitable for MR imaging, we calculated the angles of semicircular canal planes of both ears in 11 dizzy patients who had normal caloric response in both ears. The angles between adjacent canal pairs were nearly perpendicular in both ears. The angle between the posterior canal planes and head sagittal plane was 51° and significantly larger the angle between the anterior canal planes and head sagittal plane, which was 35°. The angle between the horizontal canal plane and head sagittal plane was almost orthogonal. Pairs of contralateral synergistic canal planes were not parallel, forming 10° between right and left horizontal canal planes, 17° between right anterior and left posterior canal planes and 19° between the right posterior and left anterior canal planes. Our measurement of the angles of adjacent canal pairs and the angle between each semicircular canal and head sagittal plane coincided with those of previous reports obtained from CT images and skull specimens. However, the angles between contralateral synergistic canal planes were more parallel than those of previous reports. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  8. Clinical decision-making to address poor outcomes in persistent horizontal semicircular canal benign paroxysmal positional vertigo: A case study.

    PubMed

    Moore, Brian M

    2017-05-01

    Horizontal semicircular canal BPPV (HSC-BPPV) can occur in 10-30% of BPPV cases. Lower success rates are reported for HSC-BPPV. The apogeotropic form of HSC-BPPV is more difficult to treat, as 5-40% of cases are described to be refractory to repositioning maneuvers. To describe the assessment and treatment of a patient presenting with HSC-BPPV and to demonstrate the potential use of Forced-Prolonged Positioning (FPP) as a home exercise program (HEP) for persistent HSC-BPPV in an elderly patient. An 89-year-old female referred to physical therapy with a diagnosis of BPPV. She experienced dizziness with positional changes and was found to have apogeotropic form of HSC-BPPV. To supplement maneuvers performed in the clinic, the patient was provided instructions for the FPP as her HEP. With continued symptoms and positive positional tests by week four of treatment, the patient was instructed to switch the FPP with the opposing ear directed toward the floor. Following 2 weeks of performing FPP on the opposite side, the patient reported symptoms had resolved and positional testing confirmed resolution of HSC-BPPV. There is a potential benefit of using FPP as a HEP to supplement maneuvers used in the clinic to improve outcomes in patients with HSC-BPPV that are refractory to traditional repositioning maneuvers. Prescribing the FPP maneuver as a HEP is feasible, and clinicians should consider the FPP technique as a HEP to adjunct repositioning maneuvers performed in the clinic to address persistent HSC-BPPV.

  9. Contribution of irregular semicircular canal afferents to the horizontal vestibuloocular response during constant velocity rotation

    NASA Technical Reports Server (NTRS)

    Angelaki, D. E.; Perachio, A. A.

    1993-01-01

    1. The effects of constant anodal currents (100 microA) delivered bilaterally to both labyrinths on the horizontal vestibuloocular response (VOR) were studied in squirrel monkeys during steps of angular velocity in the dark. We report that bilateral anodal currents decreased eye velocity approximately 30-50% during the period of galvanic stimulation without a change in the time constant of VOR. The decrease in eye velocity, present during steps of angular velocity, was not observed during sinusoidal head rotation at 0.2, 0.5, and 1 Hz. The results suggest that responses from irregular vestibular afferents influence VOR amplitude during constant velocity rotation.

  10. Decline in semicircular canal and otolith function with age

    PubMed Central

    Agrawal, Yuri; Zuniga, M. Geraldine; Davalos-Bichara, Marcela; Schubert, Michael C.; Walston, Jeremy D.; Hughes, Jennifer; Carey, John P.

    2012-01-01

    Objective To characterize the physiologic nature of the vestibular dysfunction that occurs with the normative aging process. Study design Cross-sectional study. Setting Tertiary care academic medical center. Patients Fifty individuals age 70 and above. Interventions Head thrust dynamic visual acuity testing (htDVA) and cervical and ocular vestibular-evoked myogenic potential (VEMP) testing. Main Outcome Measures Semicircular canal function measured by htDVA in each of the three semicircular canal planes, and saccular and utricular function measured by cVEMP and oVEMP testing, respectively. Results We observed significant declines in semicircular canal function in each of the canal planes as well as otolith function associated with aging. We found that individuals with impaired horizontal and superior semicircular canal function were likely to also have concomitant deficits in utricular but not saccular function. Overall, we noted that the prevalence of semicircular canal dysfunction was highest followed by saccular then utricular impairment, although we did observe individuals with isolated otolith deficits. Conclusions These data suggest an overall decline in semicircular canal as well as otolith function associated with aging, although the magnitude of impairment was greater for the semicircular canals than the otoliths in this elderly population. A better understanding of the specific vestibular deficits that occur with aging can inform the development of rational screening, vestibular rehabilitation and fall risk reduction strategies in older individuals. PMID:22699991

  11. Decline in semicircular canal and otolith function with age.

    PubMed

    Agrawal, Yuri; Zuniga, Maria Geraldine; Davalos-Bichara, Marcela; Schubert, Michael C; Walston, Jeremy D; Hughes, Jennifer; Carey, John P

    2012-07-01

    To characterize the physiologic nature of the vestibular dysfunction that occurs with the normative aging process. Cross-sectional study. Tertiary care academic medical center. Fifty individuals age 70 years and above. Head thrust dynamic visual acuity testing and cervical and ocular vestibular-evoked myogenic potential (VEMP) testing. Semicircular canal function measured by head thrust dynamic visual acuity testing in each of the 3 semicircular canal planes, and saccular and utricular function measured by cervical VEMP and ocular VEMP testing, respectively. We observed significant declines in semicircular canal function in each of the canal planes as well as otolith function associated with aging. We found that individuals with impaired horizontal and superior semicircular canal function also were likely to have concomitant deficits in utricular but not saccular function. Overall, we noted that the prevalence of semicircular canal dysfunction was highest followed by saccular then utricular impairment, although we did observe individuals with isolated otolith deficits. These data suggest an overall decline in semicircular canal as well as otolith function associated with aging, although the magnitude of impairment was greater for the semicircular canals than the otoliths in this elderly population. A better understanding of the specific vestibular deficits that occur with aging can inform the development of rational screening, vestibular rehabilitation, and fall risk reduction strategies in older individuals.

  12. The Age-Related Orientational Changes of Human Semicircular Canals.

    PubMed

    Lyu, Hui-Ying; Chen, Ke-Guang; Yin, Dong-Ming; Hong, Juan; Yang, Lin; Zhang, Tian-Yu; Dai, Pei-Dong

    2016-06-01

    Some changes are found in the labyrinth anatomy during postnatal development. Although the spatial orientation of semicircular canals was thought to be stable after birth, we investigated the age-related orientational changes of human semicircular canals during development. We retrospectively studied the computed tomography (CT) images of both ears of 76 subjects ranged from 1 to 70 years old. They were divided into 4 groups: group A (1-6 years), group B (7-12 years), group C (13-18 years), and group D (>18 years). The anatomical landmarks of the inner ear structures were determined from CT images. Their coordinates were imported into MATLAB software for calculating the semicircular canals orientation, angles between semicircular canal planes and the jugular bulb (JB) position. Differences between age groups were analyzed using multivariate statistics. Relationships between variables were analyzed using Pearson analysis. The angle between the anterior semicircular canal plane and the coronal plane, and the angle between the horizontal semicircular canal plane and the coronal plane were smaller in group D than those in group A (P<0.05). The JB position, especially the anteroposterior position of right JB, correlated to the semicircular canals orientation (P<0.05). However, no statistically significant differences in the angles between ipsilateral canal planes among different age groups were found. The semicircular canals had tendencies to tilt anteriorly simultaneously as a whole with age. The JB position correlated to the spatial arrangement of semicircular canals, especially the right JB. Our calculation method helps detect developmental and pathological changes in vestibular anatomy.

  13. Effect of semicircular canal dehiscence on contralateral canal bone thickness.

    PubMed

    Gracia-Tello, Borja; Cisneros, Ana; Crovetto, Rafael; Martinez, Claudio; Rodriguez, Olívia; Lecumberri, Iñigo; Crovetto, Miguel Ángel; Whyte, Jaime

    2013-01-01

    Our objective was to determine if the existence of dehiscence in the superior or posterior semicircular canal was associated with the thinning of the bone roof in the rest of the vertical canals (superior or posterior). The thickness of the superior and posterior semicircular canals contralateral to a dehiscence was studied using computerized tomography and compared statistically. When a superior semicircular canal had a dehiscence, the contralateral canal showed a significant mean decrease in its thickness of 0.5mm (SD: 0.3 mm). This was not the case if the dehiscence was in the posterior semicircular canal, where the thickness of 2.1 mm remained unchanged (SD: 1.2 mm; P=.49). When a posterior semicircular canal showed dehiscence, no significant thinning was shown in the superior semicircular (1 mm; SD: 0.4) or in the posterior contralateral (1.3 mm; SD: 0.3) canals. The existence of a dehiscence in the superior semicircular canal is associated with bone thinning in the canal on the opposite side, but not with the posterior semicircular canal. In contrast, if the dehiscence is in the posterior semicircular canal, contralateral and superior canal thickness is not modified. Copyright © 2012 Elsevier España, S.L. All rights reserved.

  14. The primate semicircular canal system and locomotion

    PubMed Central

    Spoor, Fred; Garland, Theodore; Krovitz, Gail; Ryan, Timothy M.; Silcox, Mary T.; Walker, Alan

    2007-01-01

    The semicircular canal system of vertebrates helps coordinate body movements, including stabilization of gaze during locomotion. Quantitative phylogenetically informed analysis of the radius of curvature of the three semicircular canals in 91 extant and recently extinct primate species and 119 other mammalian taxa provide support for the hypothesis that canal size varies in relation to the jerkiness of head motion during locomotion. Primate and other mammalian species studied here that are agile and have fast, jerky locomotion have significantly larger canals relative to body mass than those that move more cautiously. PMID:17576932

  15. Magnetic resonance imaging of semicircular canals.

    PubMed Central

    Sbarbati, A; Leclercq, F; Zancanaro, C; Antonakis, K

    1992-01-01

    The present paper reports the results of the first investigation of the semicircular canals in a living, small animal by means of high spatial resolution magnetic resonance imaging. This procedure is noninvasive and allows identification of the endolymphatic and perilymphatic spaces yielding a morphology quite consistent with direct anatomical examination. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:1506290

  16. [Anterior semicircular canal Benign Paroxysmal Positional Vertigo].

    PubMed

    Alzuphar, Stephen Jacques; Maire, Raphaël

    2016-10-05

    Anterior semicircular canal Benign Paroxysmal Positional Vertigo (antBPPV) is the rarest form of semicircular canalolithiasis, corresponding to about 1-2 % of the BPPV. The diagnosis is obtained by either the Dix-Hallpike maneuver or the straight head hanging positioning maneuver, which provoke a characteristic positional down-beating nystagmus. This vertical nystagmus can be associated with a torsional component that helps in localizing the affected side. The differential diagnosis of antBPPV includes the various central lesions that produce vertical down beating nystagmus (posterior fossa). Several liberatory maneuvers have been proposed for the treatment of antBPPV, but still need standardization.

  17. Superior Semicircular Canal Dehiscence (SSCD)

    MedlinePlus

    ... canal that is being activated. Analysis of the eye movements evoked by sound and pressure stimuli in patients ... to the identification of this syndrome. These evoked eye movements often align with the plane of the superior ...

  18. Spatial orientation of semicircular canals and afferent sensitivity vectors in pigeons

    NASA Technical Reports Server (NTRS)

    Dickman, J. D.

    1996-01-01

    Rotational head motion in vertebrates is detected by the semicircular canal system, whose innervating primary afferent fibers carry information about movement in specific head planes. The semicircular canals have been qualitatively examined over a number of years, and the canal planes have been quantitatively characterized in several animal species. The present study first determined the geometric relationship between individual semicircular canals and between the canals and the stereotactic head planes in pigeons. Stereotactic measurements of multiple points along the circumference of the bony canals were taken, and the measured points fitted with a three-dimensional planar surface. Direction normals to the plane's surface were calculated and used to define angles between semicircular canal pairs. Because of the unusual shape of the anterior semicircular canals in pigeons, two planes, a major and a minor, were fitted to the canal's course. Calculated angle values for all canals indicated that the horizontal and posterior semicircular canals are nearly orthogonal, but the anterior canals have substantial deviations from orthogonality with other canal planes. Next, the responses of the afferent fibers that innervate each of the semicircular canals to 0.5 Hz sinusoidal rotation about an earth-vertical axis were obtained. The head orientation relative to the rotation axis was systematically varied so that directions of maximum sensitivity for each canal afferent could be determined. These sensitivity vectors were then compared with the canal plane direction normals. The afferents that innervated specific semicircular canals formed homogeneous clusters of sensitivity vectors in different head planes. The horizontal and posterior afferents had average sensitivity vectors that were largely co-incident with the innervated canal plane direction normals. Anterior canal afferents, however, appeared to synthesize contributions from the major and minor plane components of the

  19. Matters of simulation of the semicircular canal system

    NASA Technical Reports Server (NTRS)

    Gurfinkel, V. S.; Petukhov, S. V.

    1977-01-01

    A scale model of the human semicircular canal system was developed based on the theory of dynamic similitude. This enlarged model makes it convenient to conduct tests on the vestibular processes and dynamics in the semicircular canals. Tests revealed hydromechanical interaction between canals, with asymmetry of the conditions of movement of the endolymph in the canals in opposite directions. A type of vestibular reactions, occurring with angular oscillations of the head, was predicted and demonstrated using this model and human test subjects.

  20. Use of the loud sound stimulation test in diagnosis of semicircular canal dehiscence syndrome.

    PubMed

    Yu, Ya-Feng; Zhang, Yi-Bo; Dai, Chun-Fu; Chi, Fang-Lu

    2011-04-01

    Semicircular canal dehiscence (SCD) syndrome is rare, and its diagnosis is a significant challenge in clinical practice. Our aim was to explore application of the loud sound stimulation test for diagnosing SCD syndrome. Eight cases of superior semicircular canal dehiscence (SSCD), among them two patients had bilateral dehiscences and one case of lateral semicircular canal dehiscence (LSCD). A total of 11 dehiscences were studied retrospectively. Loud sounds (pure tones, 100 dB, 110 dB nHL) at frequencies of 500, 1,000, and 2,000 Hz were used to stimulate both ears for 5 s. A temporal bone computed tomography (CT) scan with semicircular canal reconstruction was performed in all patients. Vertigo was present in seven of nine cases following loud sound stimulation. In addition, the patient with LSCD demonstrated horizontal eye movement following loud sound stimulation, whereas six patients with SSCD showed rotational eye movement. Among them, two patients with bilateral superior canal dehiscence showed a positive response to the loud sound stimulation in only one ear. The diagnoses of all patients were confirmed with a high-resolution temporal bone CT with corresponding multi-planar reconstruction of the affected semicircular canals with various size dehiscences. We conclude that the characteristic eye movement following loud sound stimulation is valuable for diagnosing SCD syndrome. In addition, the loud sound stimulation test has unique advantages, especially for confirming the affected ear and the corresponding semicircular canal.

  1. Gender and laterality in semicircular canal dehiscence syndrome.

    PubMed

    Karimnejad, K; Czerny, M S; Lookabaugh, S; Lee, D J; Mikulec, A A

    2016-08-01

    To determine if there is gender or laterality predilection in patients with semicircular canal dehiscence syndrome. A multi-institutional chart review was performed to identify patients diagnosed with semicircular canal dehiscence between 2000 and 2015. A systematic literature search was conducted using PubMed to further identify patients with semicircular canal dehiscence. Age, gender and laterality data were collected. Statistical analysis was performed to evaluate for gender or laterality preponderance. A total of 682 patients with semicircular canal dehiscence were identified by literature and chart review. Mean age of diagnosis was 49.75 years (standard deviation = 15.33). Semicircular canal dehiscence was associated with a statistically significant female predominance (chi-square = 7.185, p = 0.007); the female-to-male ratio was 1.2 to 1. Left-sided semicircular canal dehiscence was most common, followed by right-sided then bilateral (chi-square = 23.457, p < 0.001). Semicircular canal dehiscence syndrome is most commonly left-sided and exhibits a female predominance. This may be secondary to morphological cerebral hemisphere asymmetries in both sexes and a predilection of women to seek more medical care than men.

  2. Tullio phenomenon with dehiscence of the superior semicircular canal.

    PubMed

    Ostrowski, V B; Byskosh, A; Hain, T C

    2001-01-01

    The goal of the investigation was to determine if vector analysis of nystagmus in a patient with the Tullio phenomenon could determine the source of the nystagmus. The Tullio phenomenon consists of the combination of vertigo and abnormal eye and/or head movements provoked by sound. Dehiscence of the superior semicircular canal can be found in certain patients with the Tullio phenomenon. The patient was tested with pure tones ranging from 250 to 3,000 Hz at 95dB HL. The time course of the three-dimensional vector of eye movement, including torsion and vertical and horizontal displacement angles was determined by individual stop-frame analysis of digitized video. Torsion amplitude varied from 1 to 7 degrees; vertical amplitude varied from 1 to 5 degrees; and horizontal amplitude varied less than 1.5 degrees. The maximal response occurred on stimulation of the right ear with a 1,250-Hz 95-dB HL tone. This elicited a reliable counterclockwise torsional and down-beating fast phase nystagmus as seen from the examiner's point of view. Comparison of the nystagmus with known canal vectors identified the right superior semicircular canal as the source of stimulation. High-resolution computed tomography scan of the temporal bone showed a definite right superior canal dehiscence. The origin of nystagmus from the Tullio phenomenon can be identified by calculating the three-dimensional vector of the observed nystagmus. We show that vector analysis of the observed eye movement can be used to infer the source of nystagmus in these patients. The development of real-time, three-dimensional vector analysis of nystagmus is desirable.

  3. Posture control in Pusher syndrome: influence of lateral semicircular canals.

    PubMed

    Pontelli, Taiza Elaine Grespan dos Santos; Pontes-Neto, Octavio Marques; Colafêmina, José Fernando; Araújo, Draulio Barros de; Santos, Antonio Carlos; Leite, João Pereira

    2005-01-01

    Pusher syndrome is an interesting disorder of balance in patients with encephalic lesions characterized by the peculiar behavior of actively pushing away from the non-hemiparetic side and resisting against passive correction, with a tendency to fall toward the paralyzed side. The role of vestibular system on the pushing behavior is not clear. To evaluate horizontal semicircular canal function in patients with Pusher syndrome, using caloric and rotation tests. Observational prospective. We evaluated 9 inpatients with stroke and Pusher syndrome at the neurological unit of HCFMRP-USP. We applied neurological and neuropsychological exams, NIHSS, Scale for contraversive pushing (SCP), caloric and rotation tests. We evaluated 9 patients (5 men) with mean age of 71.8 +/- 5.9 and mean NIHSS of 18.33. Three patients presented contralateral directional preponderance on caloric test and we found four patients with directional preponderance on analysis of the slow phase velocity of rotation test response. Our findings indicate that a dysfunction of semicircular canals does not seem to be relevant for the clinical manifestations of the Pusher syndrome.

  4. Direct influence of temperature on the semicircular canal receptor.

    PubMed

    Suzuki, M; Kadir, A; Hayashi, N; Takamoto, M

    1998-01-01

    Effect of thermal stimulus on the vestibular receptor was studied using the isolated frog semicircular canal. The posterior (PSC) and lateral semicircular canals (LSC) were placed in the horizontal plane in frog Ringer's solution. The ampullary nerve was sucked into a glass suction electrode to record compound potentials. The steel thermal probe was positioned next to the ampullary surface to give thermal stimuli. When the PSC ampulla was cooled, the spontaneous discharge markedly increased. When the PSC ampulla was warmed, the discharge decreased. When the LSC ampulla was cooled, the discharge increased in the same manner as in the PSC. Also, warming of the LSC decreased the discharge in the same manner as in the PSC. The cupula was removed from the crista in order to eliminate the effect of volume change of the endolymph. The results were comparable to those with intact cupula in both the PSC and LSC. Cooling increased, while warming decreased the discharge. These responses are possibly due to a mechanism other than mechanical volume change, because the PSC and LSC yielded the same type of responses. Direct temperature reaction of the vestibular hair cell was suggested.

  5. Clinical Characteristics of Posterior and Lateral Semicircular Canal Dehiscence

    PubMed Central

    Spasic, Marko; Trang, Andy; Chung, Lawrance K.; Ung, Nolan; Thill, Kimberly; Zarinkhou, Golmah; Gopen, Quinton S.; Yang, Isaac

    2015-01-01

    The objective of this study was to evaluate the characteristic symptoms of and treatments for lateral semicircular canal dehiscence (LSCD) and posterior semicircular canal dehiscence (PSCD) and its proposed mechanism. A dehiscence acquired in any of the semicircular canals may evoke various auditory symptoms (autophony and inner ear conductive hearing loss) or vestibular symptoms (vertigo, the Tullio phenomenon, and Hennebert sign) by creating a “third mobile window” in the bone that enables aberrant communication between the inner ear and nearby structures. A PubMed search was performed using the keywords lateral, posterior, and semicircular canal dehiscence to identify all relevant cases. Our data suggest that PSCD, although clinically rare, is most likely associated with a high-riding jugular bulb and fibrous dysplasia. Patients may experience auditory manifestations that range from mild conductive to extensive sensorineural hearing loss. LSCD is usually associated with chronic otitis media with cholesteatoma. PMID:26682120

  6. Semicircular Canal Pressure Changes During High-intensity Acoustic Stimulation.

    PubMed

    Maxwell, Anne K; Banakis Hartl, Renee M; Greene, Nathaniel T; Benichoux, Victor; Mattingly, Jameson K; Cass, Stephen P; Tollin, Daniel J

    2017-08-01

    Acoustic stimulation generates measurable sound pressure levels in the semicircular canals. High-intensity acoustic stimuli can cause hearing loss and balance disruptions. To examine the propagation of acoustic stimuli to the vestibular end-organs, we simultaneously measured fluid pressure in the cochlea and semicircular canals during both air- and bone-conducted sound presentation. Five full-cephalic human cadaveric heads were prepared bilaterally with a mastoidectomy and extended facial recess. Vestibular pressures were measured within the superior, lateral, and posterior semicircular canals, and referenced to intracochlear pressure within the scala vestibuli with fiber-optic pressure probes. Pressures were measured concurrently with laser Doppler vibrometry measurements of stapes velocity during stimulation with both air- and bone-conduction. Stimuli were pure tones between 100 Hz and 14 kHz presented with custom closed-field loudspeakers for air-conducted sounds and via commercially available bone-anchored device for bone-conducted sounds. Pressures recorded in the superior, lateral, and posterior semicircular canals in response to sound stimulation were equal to or greater in magnitude than those recorded in the scala vestibuli (up to 20 dB higher). The pressure magnitudes varied across canals in a frequency-dependent manner. High sound pressure levels were recorded in the semicircular canals with sound stimulation, suggesting that similar acoustical energy is transmitted to the semicircular canals and the cochlea. Since these intralabyrinthine pressures exceed intracochlear pressure levels, our results suggest that the vestibular end-organs may also be at risk for injury during exposure to high-intensity acoustic stimuli known to cause trauma in the auditory system.

  7. The Video Head Impulse Test (vHIT) Detects Vertical Semicircular Canal Dysfunction

    PubMed Central

    MacDougall, Hamish Gavin; McGarvie, Leigh Andrew; Halmagyi, Gabor Michael; Curthoys, Ian Stewart; Weber, Konrad Peter

    2013-01-01

    Background The video head impulse test (vHIT) is a useful clinical tool to detect semicircular canal dysfunction. However vHIT has hitherto been limited to measurement of horizontal canals, while scleral search coils have been the only accepted method to measure head impulses in vertical canals. The goal of this study was to determine whether vHIT can detect vertical semicircular canal dysfunction as identified by scleral search coil recordings. Methods Small unpredictable head rotations were delivered by hand diagonally in the plane of the vertical semicircular canals while gaze was directed along the same plane. The planes were oriented along the left-anterior-right-posterior (LARP) canals and right-anterior-left-posterior (RALP) canals. Eye movements were recorded simultaneously in 2D with vHIT (250 Hz) and in 3D with search coils (1000 Hz). Twelve patients with unilateral, bilateral and individual semicircular canal dysfunction were tested and compared to seven normal subjects. Results Simultaneous video and search coil recordings were closely comparable. Mean VOR gain difference measured with vHIT and search coils was 0.05 (SD = 0.14) for the LARP plane and −0.04 (SD = 0.14) for the RALP plane. The coefficient of determination R2 was 0.98 for the LARP plane and 0.98 for the RALP plane and the results of the two methods were not significantly different. vHIT and search coil measures displayed comparable patterns of covert and overt catch-up saccades. Conclusions vHIT detects dysfunction of individual vertical semicircular canals in vestibular patients as accurately as scleral search coils. Unlike search coils, vHIT is non-invasive, easy to use and hence practical in clinics. PMID:23630593

  8. The video Head Impulse Test (vHIT) detects vertical semicircular canal dysfunction.

    PubMed

    Macdougall, Hamish Gavin; McGarvie, Leigh Andrew; Halmagyi, Gabor Michael; Curthoys, Ian Stewart; Weber, Konrad Peter

    2013-01-01

    The video head impulse test (vHIT) is a useful clinical tool to detect semicircular canal dysfunction. However vHIT has hitherto been limited to measurement of horizontal canals, while scleral search coils have been the only accepted method to measure head impulses in vertical canals. The goal of this study was to determine whether vHIT can detect vertical semicircular canal dysfunction as identified by scleral search coil recordings. Small unpredictable head rotations were delivered by hand diagonally in the plane of the vertical semicircular canals while gaze was directed along the same plane. The planes were oriented along the left-anterior-right-posterior (LARP) canals and right-anterior-left-posterior (RALP) canals. Eye movements were recorded simultaneously in 2D with vHIT (250 Hz) and in 3D with search coils (1000 Hz). Twelve patients with unilateral, bilateral and individual semicircular canal dysfunction were tested and compared to seven normal subjects. Simultaneous video and search coil recordings were closely comparable. Mean VOR gain difference measured with vHIT and search coils was 0.05 (SD = 0.14) for the LARP plane and -0.04 (SD = 0.14) for the RALP plane. The coefficient of determination R(2) was 0.98 for the LARP plane and 0.98 for the RALP plane and the results of the two methods were not significantly different. vHIT and search coil measures displayed comparable patterns of covert and overt catch-up saccades. vHIT detects dysfunction of individual vertical semicircular canals in vestibular patients as accurately as scleral search coils. Unlike search coils, vHIT is non-invasive, easy to use and hence practical in clinics.

  9. Changes of ampulla pressure in the semicircular canal of pigeons by caloric stimulation

    NASA Astrophysics Data System (ADS)

    Wada, Yoshiro; Suzuki, Hiroyuki; Watanabe, Satoru

    Still now several hypotheses about the mechanisms of the caloric nystagmus have been in conclusive. In this study we confirmed the convection effect and the volume change effect of the endolymph in horizontal semicircular canal following the caloric stimulation using pigeons ( Columba livia). Although the direction of the caloric nystagmus depended on the head position and the stimulus site of calorization, the caloric nystagmus disappeared after plugging of horizontal semicircular canal. On the other hand, the ampulla pressure increased by cold calorization and decreased by hot calorization and these pressure changes had no relation to the head position. These results show that the main role of the mechanisms of the caloric nystagmus under 1G is the convection effect but the volume change effect may act on the caloric nystagmus not only under 1G but also under microgravity.

  10. Intranasal scopolamine affects the semicircular canals centrally and peripherally.

    PubMed

    Weerts, Aurélie P; Putcha, Lakshmi; Hoag, Stephen W; Hallgren, Emma; Van Ombergen, Angelique; Van de Heyning, Paul H; Wuyts, Floris L

    2015-08-01

    Space motion sickness (SMS), a condition caused by an intravestibular conflict, remains an important obstacle that astronauts encounter during the first days in space. Promethazine is currently the standard treatment of SMS, but scopolamine is used by some astronauts to prevent SMS. However, the oral and transdermal routes of administration of scopolamine are known to have substantial drawbacks. Intranasal administration of scopolamine ensures a fast absorption and rapid onset of therapeutic effect, which might prove to be suitable for use during spaceflights. The aim of this study was to evaluate the effects of intranasally administered scopolamine (0.4 mg) on the semicircular canals (SCCs) and the otoliths. This double-blind, placebo-controlled study was performed on 19 healthy male subjects. The function of the horizontal SCC and the vestibulo-ocular reflex, as well as the saccular function and utricular function, were evaluated. Scopolamine turned out to affect mainly the SCCs centrally and peripherally but also the utricles to a lesser extent. Centrally, the most probable site of action is the medial vestibular nucleus, where the highest density of muscarinic receptors has been demonstrated and afferent fibers from the SCCs and utricles synapse. Furthermore, our results suggest the presence of muscarinic receptors in the peripheral vestibular system on which scopolamine has a suppressive effect. Given the depressant actions on the SCCs, it is suggested that the pharmacodynamic effect of scopolamine may be attributed to the obliteration of intravestibular conflict that arises during (S)MS.

  11. [Effect of some antibiotics on semi-circular canal activity in the frog (Rana esculenta)].

    PubMed

    Gallais, A; Gribenski, A

    1975-01-01

    We have studied the action of two ototoxic antibiotics (streptomycin and gentamycin) on the activity of the horizontal semicircular canal in comparison with those of penicillin and 7 g/1 NaCl solution, all of them being injected into the labyrinthic cavity. Only streptomycin and gentamycin have a specific action, and the one of streptomycin is much more important than the one of gentamycin.

  12. Low-frequency otolith and semicircular canal interactions after canal inactivation

    NASA Technical Reports Server (NTRS)

    Angelaki, D. E.; Merfeld, D. M.; Hess, B. J.

    2000-01-01

    During sustained constant velocity and low-frequency off-vertical axis rotations (OVAR), otolith signals contribute significantly to slow-phase eye velocity. The adaptive plasticity of these responses was investigated here after semicircular canal plugging. Inactivation of semicircular canals results in a highly compromised and deficient vestibulo-ocular reflex (VOR). Based on the VOR enhancement hypothesis, one could expect an adaptive increase of otolith-borne angular velocity signals due to combined otolith/canal inputs after inactivation of the semicircular canals. Contrary to expectations, however, the steady-state slow-phase velocity during constant velocity OVAR decreased in amplitude over time. A similar progressive decrease in VOR gain was also observed during low-frequency off-vertical axis oscillations. This response deterioration was present in animals with either lateral or vertical semicircular canals inactivated and was limited to the plane(s) of the plugged canals. The results are consistent with the idea that the low-frequency otolith signals do not simply enhance VOR responses. Rather, the nervous system appears to correlate vestibular sensory information from the otoliths and the semicircular canals to generate an integral response to head motion.

  13. Semicircular canal contributions to the three-dimensional vestibuloocular reflex: a model-based approach.

    PubMed

    Yakushin, S; Dai, M; Suzuki, J; Raphan, T; Cohen, B

    1995-12-01

    1. We studied the contribution of the individual semicircular canals to the generation of horizontal and torsional eye movements in cynomolgus monkeys. Eye movements were elicited by sinusoidal rotation about a vertical (gravitational) axis at 0.2 Hz with the animals tilted in various attitudes of static forward or backward pitch. The gains of the horizontal and torsional components of the vestibuloocular reflex (VOR) were measured for each tilt position. The gains as a function of tilt position were fit with sinusoidal functions, and spatial gains and phases were determined. After control responses were recorded, the semicircular canals were plugged, animals were allowed to adapt, and the test procedure was repeated. Animals were prepared with only the anterior and posterior canals intact [vertical canal (VC) animals], with only the lateral canals intact [lateral canal (LC) animal], and with only one anterior and the contralateral posterior canals intact [right anterior and left posterior canal (RALP) animals; left anterior and right posterior canal (LARP) animals]. 2. In normal animals, the gain of the horizontal (yaw axis) velocity of the compensatory eye movements decreased as they were pitched forward or backward, and a torsional velocity appeared, reversing phase at the peak of the horizontal gain. After the anterior and posterior canals were plugged (LC animal), the horizontal component was reduced when the animal was tilted backward; the gain was zero with about -60 degrees of backward tilt. The spatial phase of the torsional component had the same characteristics. This is consistent with the fact that both responses were produced by the lateral canals, which from our results are tilted between 28 and 39 degrees above the horizontal stereotaxic plane. 3. After both lateral canals were plugged (VC animals), horizontal velocity was reduced in the upright position but increased as the animals were pitched backward relative to the axis of rotation. Torsional

  14. [Superior semicircular canal dehiscence syndrome: a case of Tullio phenomenon].

    PubMed

    Rohrmeier, C; Hilber, H; Strutz, J

    2010-10-01

    Superior semicircular canal dehiscence syndrome is a clinical picture with sound and pressure-induced vertigo, autophony, hearing loss and a lowered bone conduction threshold. It is an important differential diagnosis to otosclerosis and patent eustachian tube. Diagnostic investigations include audiometric testing, nystagmus provocation, computed tomography and vestibular evoked myogenic potentials. Surgical repair of the dehiscence represents a curative therapeutic option. We describe the disease symptoms on the basis of a typical case.

  15. Hair-Cell Versus Afferent Adaptation in the Semicircular Canals

    PubMed Central

    Rabbitt, R. D.; Boyle, R.; Holstein, G. R.; Highstein, S. M.

    2010-01-01

    The time course and extent of adaptation in semicircular canal hair cells was compared to adaptation in primary afferent neurons for physiological stimuli in vivo to study the origins of the neural code transmitted to the brain. The oyster toadfish, Opsanus tau, was used as the experimental model. Afferent firing-rate adaptation followed a double-exponential time course in response to step cupula displacements. The dominant adaptation time constant varied considerably among afferent fibers and spanned six orders of magnitude for the population (~1 ms to >1,000 s). For sinusoidal stimuli (0.1–20 Hz), the rapidly adapting afferents exhibited a 90° phase lead and frequency-dependent gain, whereas slowly adapting afferents exhibited a flat gain and no phase lead. Hair-cell voltage and current modulations were similar to the slowly adapting afferents and exhibited a relatively flat gain with very little phase lead over the physiological bandwidth and dynamic range tested. Semicircular canal microphonics also showed responses consistent with the slowly adapting subset of afferents and with hair cells. The relatively broad diversity of afferent adaptation time constants and frequency-dependent discharge modulations relative to hair-cell voltage implicate a subsequent site of adaptation that plays a major role in further shaping the temporal characteristics of semicircular canal afferent neural signals. PMID:15306633

  16. Building a better semicircular canal: could we balance any better?

    NASA Astrophysics Data System (ADS)

    Squires, Todd

    2004-03-01

    Every vertebrate organism uses fluid-filled semicircular canals (SCCs) to sense rotation -- and thus to balance, navigate and hunt. Whereas the size of most organs typically scales with the size of the organism itself, the SCC are all about the same size -- whether in lizards, mice, humans, or whales. What is so special about these dimensions? We consider fluid flow in the canals and elastic deformations of a sensory membrane, and isolate physical and physiological constraints required for successful SCC function. We demonstrate that the `parameter space' open to evolution is almost completely constrained; furthermore, the most sensitive possible SCC has dimensions that are remarkably close to those common to all vertebrates.

  17. Physiological localization of the semicircular canal receptors in the crista.

    PubMed

    Suzuki, M; Harada, Y; Oue, K

    1985-01-01

    Isolated posterior semicircular canals from the bull frog model were used. The cupula was removed from the crista and the sensory cilia on the crista were depressed toward the canal side by using a glass micropipette. Seven different points were selected for stimulation on the ampullary wall. Ampullary nerve action potentials induced by depression were recorded and were converted into spike-density histograms. Response decremental time constants were measured on these histograms. The longest time constant was measured at the two lateral points of stimulation and progressively shortened toward the central point of stimulation. These results indicate that the origin of the adaptation is possibly sensorineural.

  18. [Peculiarities in the development of the superior semicircular canal].

    PubMed

    Yus, Carmen; Cisneros, Ana I; Obón, Jesús; Crovetto, Rafael; Fraile, Jesús; Crovetto, Miguel A; Whyte, Jaime

    2014-01-01

    Our objective was to study the ontogeny of the superior semicircular canal in order to describe its peculiarities. We analyzed 76 series of human embryos aged between 32 days (6mm) and newborns. The samples were cut serially and stained using Martin's trichrome technique. In semicircular canal development there were a number of peculiarities, such as: a defined chronological sequence of osteogenesis with a variable rate of ossification; the fact that each nucleus of ossification was involved in the formation of one of its covers (the upper in the superficial and the lower in the deep); the appearance of transitory dehiscence; and canal closure by means of bone with laminar pattern, with a minimum thickness of 0.1mm. The peculiarities in canal development could explain the origin of pathological dehiscence in the canal, whether congenital or acquired. Copyright © 2013 Elsevier España, S.L. y Sociedad Española de Otorrinolaringología y Patología Cérvico-Facial. All rights reserved.

  19. Locomotor head movements and semicircular canal morphology in primates

    PubMed Central

    Malinzak, Michael D.; Kay, Richard F.; Hullar, Timothy E.

    2012-01-01

    Animal locomotion causes head rotations, which are detected by the semicircular canals of the inner ear. Morphologic features of the canals influence rotational sensitivity, and so it is hypothesized that locomotion and canal morphology are functionally related. Most prior research has compared subjective assessments of animal “agility” with a single determinant of rotational sensitivity: the mean canal radius of curvature (R). In fact, the paired variables of R and body mass are correlated with agility and have been used to infer locomotion in extinct species. To refine models of canal functional morphology and to improve locomotor inferences for extinct species, we compare 3D vector measurements of head rotation during locomotion with 3D vector measures of canal sensitivity. Contrary to the predictions of conventional models that are based upon R, we find that axes of rapid head rotation are not aligned with axes of either high or low sensitivity. Instead, animals with fast head rotations have similar sensitivities in all directions, which they achieve by orienting the three canals of each ear orthogonally (i.e., along planes at 90° angles to one another). The extent to which the canal configuration approaches orthogonality is correlated with rotational head speed independent of body mass and phylogeny, whereas R is not. PMID:23045679

  20. Perspectives for the comprehensive examination of semicircular canal and otolith function.

    PubMed

    Clarke, A H

    2001-12-01

    A review is presented on the three-dimensional aspects of the vestibulo-oculomotor system and the current functional tests for unilateral examination of the individual receptors in the vestibular labyrinth. In the presentation, attention is directed towards the recently developed vestibular tests, which promise a more comprehensive examination of labyrinth function. More explicitly, unilateral tests for the utricle, saccule and the individual semicircular canals are discussed. Caloric irrigation and rotatory testing are widely used as tests for the integrity of the (horizontal) semicircular canals. Little useful diagnosis is made however on the vertical canals, not to mention the otolith organs. A promising approach to the examination of individual semicircular canal function has been described. This involves the perception of self-rotation in each of the planes of the semicircular canals. The patient/subject is rotated by an arbitrary amount on a standard Barany chair and then required to return the chair to its original position, by joystick control of the chair velocity. In order to test the vertical canals, the head of the subject/patient is positioned so that the plane of each canal lies in the plane of rotation. A promising unilateral test of saccular function involves the use of vestibular evoked myogenic potentials. Here it has been demonstrated that the saccules can be activated using brief, high-intensity acoustic clicks. The myogenic potential is measured using surface electrodes over the sternocleidomastoid muscles. Initial data from patients has indicated that the test is specific for unilateral saccule disorders. The unilateral test of utricle function is based on the eccentric displacement profile. Thus, eccentric displacement of the head to 3.5 cm during constant velocity rotation about the earth-vertical axis generates an adequate unilateral stimulation of the otolith organ, without involving the semicircular canals. This paradigm has also proved

  1. Inactivation of Semicircular Canals Causes Adaptive Increases in Otolith-driven Tilt Responses

    NASA Technical Reports Server (NTRS)

    Angelaki, Dora E.; Newlands, Shawn D.; Dickman, J. David

    2002-01-01

    Growing experimental and theoretical evidence suggests a functional synergy in the processing of otolith and semicircular canal signals for the generation of the vestibulo-ocular reflexes (VORs). In this study we have further tested this functional interaction by quantifying the adaptive changes in the otolith-ocular system during both rotational and translational movements after surgical inactivation of the semicircular canals. For 0.1- 0.5 Hz (stimuli for which there is no recovery of responses from the plugged canals), pitch and roll VOR gains recovered during earth- horizontal (but not earth-vertical) axis rotations. Corresponding changes were also observed in eye movements elicited by translational motion (0.1 - 5 Hz). Specifically, torsional eye movements increased during lateral motion, whereas vertical eye movements increased during fore-aft motion. The findings indicate that otolith signals can be adapted according to compromised strategy that leads to improved gaze stabilization during motion. Because canal-plugged animals permanently lose the ability to discriminate gravitoinertial accelerations, adapted animals can use the presence of gravity through otolith-driven tilt responses to assist gaze stabilization during earth-horizontal axis rotations.

  2. Horizontal canal benign paroxysmal positional vertigo in a fighter pilot

    PubMed Central

    Xie, Su-Jiang; Wang, Jiang-Chang; Ding, Li; Sun, Xi-Qing

    2011-01-01

    Benign paroxysmal positional vertigo (BPPV) is the most common disorder of the peripheral vestibular system, characterized by intense, positional provoked vertigo. BPPV is thought to occur due to canalithiasis of the posterior semicircular canal. Recently, a new entity of BPPV, known as horizontal canal (HC)-BPPV, has been recognized. Although only 3 to 8% of BPPV is due to horizontal canal involvement, HC-BPPV is not rare. We present a case of a naval fighter pilot who had an incident of HC-BPPV on the ground. The pilot aeromedical evaluation and considerations are discussed. PMID:21716841

  3. Horizontal canal benign paroxysmal positional vertigo in a fighter pilot.

    PubMed

    Xie, Su-Jiang; Wang, Jiang-Chang; Ding, Li; Sun, Xi-Qing

    2011-01-01

    Benign paroxysmal positional vertigo (BPPV) is the most common disorder of the peripheral vestibular system, characterized by intense, positional provoked vertigo. BPPV is thought to occur due to canalithiasis of the posterior semicircular canal. Recently, a new entity of BPPV, known as horizontal canal (HC)-BPPV, has been recognized. Although only 3 to 8% of BPPV is due to horizontal canal involvement, HC-BPPV is not rare. We present a case of a naval fighter pilot who had an incident of HC-BPPV on the ground. The pilot aeromedical evaluation and considerations are discussed.

  4. An Electrokinetic Model of Transduction in the Semicircular Canal

    PubMed Central

    O'Leary, Dennis P.

    1970-01-01

    Transduction in the semicircular canal was studied by focusing an infrared beam on either side of exposed ampullae from the posterior canals of Rana pipiens. The direction of fluid movement resulting from a stimulus was inferred by observing the polarity of the change in afferent impulse mean rate relative to the spontaneous value. On the basis of the accepted functional polarization of this receptor, the results indicate that fluid moved toward the warmer side of the ampulla. Convection and thermal reception were shown to be unlikely explanations for these results. Morover, cupular displacements toward the warmer side would not be expected. Because thermo-osmosis can cause fluid to move toward the warmer side in a gelatin membrane, the results can be interpreted as evidence that thermo-osmosis occurred in the gelatinous cupula and influenced the transduction mechanism. Thermo-osmosis of liquids appears to be due to an electric field that is set up in a charged membrane; hence, the hair cells might have detected an electric field that occurred in the cupula during thermo-osmosis. Electroreception might be an important link in the transduction of physiological stimuli also. Rotational stimuli could result in weak electric fields in the cupula by the mechanoelectric effect. Cupular displacements could be important for large stimuli, but extrapolations to threshold stimuli suggest displacements of angstrom amplitudes. Therefore, electroreception by the hair cells could be an explanation of the great sensitivity that has been observed in the semicircular canal and other labyrinthine receptors. PMID:5496906

  5. Superior Semicircular Canal Dehiscence Syndrome – Diagnosis and Surgical Management

    PubMed Central

    Palma Diaz, Marite; Cisneros Lesser, Juan Carlos; Vega Alarcón, Alfredo

    2017-01-01

    Introduction Superior semicircular canal dehiscence syndrome was described by Minor et al in 1998. It is a troublesome syndrome that results in vertigo and oscillopsia induced by loud sounds or changes in the pressure of the external auditory canal or middle ear. Patients may present with autophony, hyperacusis, pulsatile tinnitus and hearing loss. When symptoms are mild, they are usually managed conservatively, but surgical intervention may be needed for patients with debilitating symptoms. Objective The aim of this manuscript is to review the different surgical techniques used to repair the superior semicircular canal dehiscence. Data Sources PubMed and Ovid-SP databases. Data Synthesis The different approaches are described and discussed, as well as their limitations. We also review the advantages and disadvantages of the plugging, capping and resurfacing techniques to repair the dehiscence. Conclusions Each of the surgical approaches has advantages and disadvantages. The middle fossa approach gives a better view of the dehiscence, but comes with a higher morbidity than the transmastoid approach. Endoscopic assistance may be advantageous during the middle cranial fossa approach for better visualization. The plugging and capping techniques are associated with higher success rates than resurfacing, with no added risk of hearing loss. PMID:28382131

  6. A comparative study of the isolated anterior and posterior semicircular canals of the bull frog.

    PubMed

    Suzuki, M; Harada, Y; Omura, R; Hirakawa, H

    1987-01-01

    The anterior semicircular canals of bull frogs were isolated and the cupula was removed from the crista and the sensory cilia on the crista were depressed toward the canal side by a glass micropipette. Seven points on the crista were selected for stimulation. Decremental time constants of the anterior ampullary nerve action potentials were measured. The longer time constants were measured at the lateral points of stimulation which progressively shortened toward the central point. The overall values of the time constant were significantly shorter than those of the posterior semicircular canal. This indicates that the anterior semicircular canal has a larger number of phasic receptors than the posterior canal.

  7. Building a better semicircular canal: could we balance any better?

    NASA Astrophysics Data System (ADS)

    Squires, Todd

    2003-11-01

    Every vertebrate organism uses fluid-filled semi-circular canals (SCC) to sense angular rotation -- and thus to balance, navigate, and hunt. Whereas the size of most organs typically scales with the size of the organism itself, the SCC are all about the same size--whether in lizards, mice, humans or whales. What is so special about these dimensions? We consider fluid flow in the canals and elastic deformations of a sensory membrane, and isolate physical and physiological constraints required for successful SCC function. We demonstrate that the `parameter space' open to evolution is almost completely constrained; furthermore, the most sensitive possible SCC has dimensions that are remarkably close to those common to all vertebrates.

  8. Evolution of locomotion in Anthropoidea: the semicircular canal evidence

    PubMed Central

    Ryan, Timothy M.; Silcox, Mary T.; Walker, Alan; Mao, Xianyun; Begun, David R.; Benefit, Brenda R.; Gingerich, Philip D.; Köhler, Meike; Kordos, László; McCrossin, Monte L.; Moyà-Solà, Salvador; Sanders, William J.; Seiffert, Erik R.; Simons, Elwyn; Zalmout, Iyad S.; Spoor, Fred

    2012-01-01

    Our understanding of locomotor evolution in anthropoid primates has been limited to those taxa for which good postcranial fossil material and appropriate modern analogues are available. We report the results of an analysis of semicircular canal size variation in 16 fossil anthropoid species dating from the Late Eocene to the Late Miocene, and use these data to reconstruct evolutionary changes in locomotor adaptations in anthropoid primates over the last 35 Ma. Phylogenetically informed regression analyses of semicircular canal size reveal three important aspects of anthropoid locomotor evolution: (i) the earliest anthropoid primates engaged in relatively slow locomotor behaviours, suggesting that this was the basal anthropoid pattern; (ii) platyrrhines from the Miocene of South America were relatively agile compared with earlier anthropoids; and (iii) while the last common ancestor of cercopithecoids and hominoids likely was relatively slow like earlier stem catarrhines, the results suggest that the basal crown catarrhine may have been a relatively agile animal. The latter scenario would indicate that hominoids of the later Miocene secondarily derived their relatively slow locomotor repertoires. PMID:22696520

  9. Evolution of locomotion in Anthropoidea: the semicircular canal evidence.

    PubMed

    Ryan, Timothy M; Silcox, Mary T; Walker, Alan; Mao, Xianyun; Begun, David R; Benefit, Brenda R; Gingerich, Philip D; Köhler, Meike; Kordos, László; McCrossin, Monte L; Moyà-Solà, Salvador; Sanders, William J; Seiffert, Erik R; Simons, Elwyn; Zalmout, Iyad S; Spoor, Fred

    2012-09-07

    Our understanding of locomotor evolution in anthropoid primates has been limited to those taxa for which good postcranial fossil material and appropriate modern analogues are available. We report the results of an analysis of semicircular canal size variation in 16 fossil anthropoid species dating from the Late Eocene to the Late Miocene, and use these data to reconstruct evolutionary changes in locomotor adaptations in anthropoid primates over the last 35 Ma. Phylogenetically informed regression analyses of semicircular canal size reveal three important aspects of anthropoid locomotor evolution: (i) the earliest anthropoid primates engaged in relatively slow locomotor behaviours, suggesting that this was the basal anthropoid pattern; (ii) platyrrhines from the Miocene of South America were relatively agile compared with earlier anthropoids; and (iii) while the last common ancestor of cercopithecoids and hominoids likely was relatively slow like earlier stem catarrhines, the results suggest that the basal crown catarrhine may have been a relatively agile animal. The latter scenario would indicate that hominoids of the later Miocene secondarily derived their relatively slow locomotor repertoires.

  10. Semicircular Canals Circumvent Brownian Motion Overload of Mechanoreceptor Hair Cells.

    PubMed

    Muller, Mees; Heeck, Kier; Elemans, Coen P H

    2016-01-01

    Vertebrate semicircular canals (SCC) first appeared in the vertebrates (i.e. ancestral fish) over 600 million years ago. In SCC the principal mechanoreceptors are hair cells, which as compared to cochlear hair cells are distinctly longer (70 vs. 7 μm), 10 times more compliant to bending (44 vs. 500 nN/m), and have a 100-fold higher tip displacement threshold (< 10 μm vs. <400 nm). We have developed biomechanical models of vertebrate hair cells where the bundle is approximated as a stiff, cylindrical elastic rod subject to friction and thermal agitation. Our models suggest that the above differences aid SCC hair cells in circumventing the masking effects of Brownian motion noise of about 70 nm, and thereby permit transduction of very low frequency (<10 Hz) signals. We observe that very low frequency mechanoreception requires increased stimulus amplitude, and argue that this is adaptive to circumvent Brownian motion overload at the hair bundles. We suggest that the selective advantage of detecting such low frequency stimuli may have favoured the evolution of large guiding structures such as semicircular canals and otoliths to overcome Brownian Motion noise at the level of the mechanoreceptors of the SCC.

  11. Semicircular Canals Circumvent Brownian Motion Overload of Mechanoreceptor Hair Cells

    PubMed Central

    Muller, Mees; Heeck, Kier

    2016-01-01

    Vertebrate semicircular canals (SCC) first appeared in the vertebrates (i.e. ancestral fish) over 600 million years ago. In SCC the principal mechanoreceptors are hair cells, which as compared to cochlear hair cells are distinctly longer (70 vs. 7 μm), 10 times more compliant to bending (44 vs. 500 nN/m), and have a 100-fold higher tip displacement threshold (< 10 μm vs. <400 nm). We have developed biomechanical models of vertebrate hair cells where the bundle is approximated as a stiff, cylindrical elastic rod subject to friction and thermal agitation. Our models suggest that the above differences aid SCC hair cells in circumventing the masking effects of Brownian motion noise of about 70 nm, and thereby permit transduction of very low frequency (<10 Hz) signals. We observe that very low frequency mechanoreception requires increased stimulus amplitude, and argue that this is adaptive to circumvent Brownian motion overload at the hair bundles. We suggest that the selective advantage of detecting such low frequency stimuli may have favoured the evolution of large guiding structures such as semicircular canals and otoliths to overcome Brownian Motion noise at the level of the mechanoreceptors of the SCC. PMID:27448330

  12. Changes of endolymphatic pressure in the semicircular canal of pigeon by caloric stimulation

    NASA Astrophysics Data System (ADS)

    Wada, Y.; Suzuki, H.; Watanabe, S.

    1994-08-01

    It gets into difficult to explain the mechanism of caloric nystagmus only by convection theory from results of microgravity experiments. One of the other theories is an occurrence of a relative volume change due to a temperature change. Since the volume change must lead to a pressure change after caloric stimulation, we tried to measure the ampulla pressure of the horizontal semicircular canal in pigeons (Columba livia) using an improved servo micropipette system. The main result was that the ampulla pressure increased by cooling and decreased by heating. The changes of the ampulla pressure depended on the temperature change but were not influenced by the pigeon's head position.

  13. Functional Implications of Ubiquitous Semicircular Canal Non-Orthogonality in Mammals

    PubMed Central

    Berlin, Jeri C.; Kirk, E. Christopher; Rowe, Timothy B.

    2013-01-01

    The ‘canonical model’ of semicircular canal orientation in mammals assumes that 1) the three ipsilateral canals of an inner ear exist in orthogonal planes (i.e., orthogonality), 2) corresponding left and right canal pairs have equivalent angles (i.e., angle symmetry), and 3) contralateral synergistic canals occupy parallel planes (i.e., coplanarity). However, descriptions of vestibular anatomy that quantify semicircular canal orientation in single species often diverge substantially from this model. Data for primates further suggest that semicircular canal orthogonality varies predictably with the angular head velocities encountered in locomotion. These observations raise the possibility that orthogonality, symmetry, and coplanarity are misleading descriptors of semicircular canal orientation in mammals, and that deviations from these norms could have significant functional consequences. Here we critically assess the canonical model of semicircular canal orientation using high-resolution X-ray computed tomography scans of 39 mammal species. We find that substantial deviations from orthogonality, angle symmetry, and coplanarity are the rule for the mammals in our comparative sample. Furthermore, the degree to which the semicircular canals of a given species deviate from orthogonality is negatively correlated with estimated vestibular sensitivity. We conclude that the available comparative morphometric data do not support the canonical model and that its overemphasis as a heuristic generalization obscures a large amount of functionally relevant variation in semicircular canal orientation between species. PMID:24260256

  14. Anatomy of the lamprey ear: morphological evidence for occurrence of horizontal semicircular ducts in the labyrinth of Petromyzon marinus

    PubMed Central

    Maklad, Adel; Reed, Caitlyn; Johnson, Nicolas S; Fritzsch, Bernd

    2014-01-01

    In jawed (gnathostome) vertebrates, the inner ears have three semicircular canals arranged orthogonally in the three Cartesian planes: one horizontal (lateral) and two vertical canals. They function as detectors for angular acceleration in their respective planes. Living jawless craniates, cyclostomes (hagfish and lamprey) and their fossil records seemingly lack a lateral horizontal canal. The jawless vertebrate hagfish inner ear is described as a torus or doughnut, having one vertical canal, and the jawless vertebrate lamprey having two. These observations on the anatomy of the cyclostome (jawless vertebrate) inner ear have been unchallenged for over a century, and the question of how these jawless vertebrates perceive angular acceleration in the yaw (horizontal) planes has remained open. To provide an answer to this open question we reevaluated the anatomy of the inner ear in the lamprey, using stereoscopic dissection and scanning electron microscopy. The present study reveals a novel observation: the lamprey has two horizontal semicircular ducts in each labyrinth. Furthermore, the horizontal ducts in the lamprey, in contrast to those of jawed vertebrates, are located on the medial surface in the labyrinth rather than on the lateral surface. Our data on the lamprey horizontal duct suggest that the appearance of the horizontal canal characteristic of gnathostomes (lateral) and lampreys (medial) are mutually exclusive and indicate a parallel evolution of both systems, one in cyclostomes and one in gnathostome ancestors. PMID:24438368

  15. Anatomy of the lamprey ear: morphological evidence for occurrence of horizontal semicircular ducts in the labyrinth of Petromyzon marinus.

    PubMed

    Maklad, Adel; Reed, Caitlyn; Johnson, Nicolas S; Fritzsch, Bernd

    2014-04-01

    In jawed (gnathostome) vertebrates, the inner ears have three semicircular canals arranged orthogonally in the three Cartesian planes: one horizontal (lateral) and two vertical canals. They function as detectors for angular acceleration in their respective planes. Living jawless craniates, cyclostomes (hagfish and lamprey) and their fossil records seemingly lack a lateral horizontal canal. The jawless vertebrate hagfish inner ear is described as a torus or doughnut, having one vertical canal, and the jawless vertebrate lamprey having two. These observations on the anatomy of the cyclostome (jawless vertebrate) inner ear have been unchallenged for over a century, and the question of how these jawless vertebrates perceive angular acceleration in the yaw (horizontal) planes has remained open. To provide an answer to this open question we reevaluated the anatomy of the inner ear in the lamprey, using stereoscopic dissection and scanning electron microscopy. The present study reveals a novel observation: the lamprey has two horizontal semicircular ducts in each labyrinth. Furthermore, the horizontal ducts in the lamprey, in contrast to those of jawed vertebrates, are located on the medial surface in the labyrinth rather than on the lateral surface. Our data on the lamprey horizontal duct suggest that the appearance of the horizontal canal characteristic of gnathostomes (lateral) and lampreys (medial) are mutually exclusive and indicate a parallel evolution of both systems, one in cyclostomes and one in gnathostome ancestors.

  16. Anatomy of the lamprey ear: morphological evidence for occurrence of horizontal semicircular ducts in the labyrinth of Petromyzon marinus

    USGS Publications Warehouse

    Maklad, Adel; Reed, Caitlyn; Johnson, Nicholas S.; Fritzsch, Bernd

    2014-01-01

    In jawed (gnathostome) vertebrates, the inner ears have three semicircular canals arranged orthogonally in the three Cartesian planes: one horizontal (lateral) and two vertical canals. They function as detectors for angular acceleration in their respective planes. Living jawless craniates, cyclostomes (hagfish and lamprey) and their fossil records seemingly lack a lateral horizontal canal. The jawless vertebrate hagfish inner ear is described as a torus or doughnut, having one vertical canal, and the jawless vertebrate lamprey having two. These observations on the anatomy of the cyclostome (jawless vertebrate) inner ear have been unchallenged for over a century, and the question of how these jawless vertebrates perceive angular acceleration in the yaw (horizontal) planes has remained open. To provide an answer to this open question we reevaluated the anatomy of the inner ear in the lamprey, using stereoscopic dissection and scanning electron microscopy. The present study reveals a novel observation: the lamprey has two horizontal semicircular ducts in each labyrinth. Furthermore, the horizontal ducts in the lamprey, in contrast to those of jawed vertebrates, are located on the medial surface in the labyrinth rather than on the lateral surface. Our data on the lamprey horizontal duct suggest that the appearance of the horizontal canal characteristic of gnathostomes (lateral) and lampreys (medial) are mutually exclusive and indicate a parallel evolution of both systems, one in cyclostomes and one in gnathostome ancestors.

  17. Determinants of Spatial and Temporal Coding by Semicircular Canal Afferents

    PubMed Central

    Highstein, Stephen M.; Rabbitt, Richard D.; Holstein, Gay R.; Boyle, Richard D.

    2010-01-01

    The vestibular semicircular canals are internal sensors that signal the magnitude, direction, and temporal properties of angular head motion. Fluid mechanics within the 3-canal labyrinth code the direction of movement and integrate angular acceleration stimuli over time. Directional coding is accomplished by decomposition of complex angular accelerations into 3 biomechanical components—one component exciting each of the 3 ampullary organs and associated afferent nerve bundles separately. For low-frequency angular motion stimuli, fluid displacement within each canal is proportional to angular acceleration. At higher frequencies, above the lower corner frequency, real-time integration is accomplished by viscous forces arising from the movement of fluid within the slender lumen of each canal. This results in angular velocity sensitive fluid displacements. Reflecting this, a subset of afferent fibers indeed report angular acceleration to the brain for low frequencies of head movement and report angular velocity for higher frequencies. However, a substantial number of afferent fibers also report angular acceleration, or a signal between acceleration and velocity, even at frequencies where the endolymph displacement is known to follow angular head velocity. These non-velocity-sensitive afferent signals cannot be attributed to canal biomechanics alone. The responses of non-velocity-sensitive cells include a mathematical differentiation (first-order or fractional) imparted by hair-cell and/or afferent complexes. This mathematical differentiation from velocity to acceleration cannot be attributed to hair cell ionic currents, but occurs as a result of the dynamics of synaptic transmission between hair cells and their primary afferent fibers. The evidence for this conclusion is reviewed below. PMID:15845995

  18. Orientation of the lateral semicircular canal in Xenarthra and its links with head posture and phylogeny.

    PubMed

    Coutier, Florence; Hautier, Lionel; Cornette, Raphaël; Amson, Eli; Billet, Guillaume

    2017-02-10

    The orientation of the semicircular canals of the inner ear in the skull of vertebrates is one of the determinants of the capacity of this system to detect a given rotational movement of the head. Past functional studies on the spatial orientation of the semicircular canals essentially focused on the lateral semicircular canal (LSC), which is supposedly held close to horizontal during rest and/or alert behaviors. However, they generally investigated this feature in only a few and distantly related taxa. Based on 3D-models reconstructed from µCT-scans of skulls, we examined the diversity of orientations of the LSC within one of the four major clades of placental mammals, that is, the superorder Xenarthra, with a data set that includes almost all extant genera and two extinct taxa. We observed a wide diversity of LSC orientations relative to the basicranium at both intraspecific and interspecific scales. The estimated phylogenetic imprint on the orientation of the LSC was significant but rather low within the superorder, though some phylogenetic conservatism was detected for armadillos that were characterized by a strongly tilted LSC. A convergence between extant suspensory sloths was also detected, both genera showing a weakly tilted LSC. Our preliminary analysis of usual head posture in extant xenarthrans based on photographs of living animals further revealed that the LSC orientation in armadillos is congruent with a strongly nose-down head posture. It also portrayed a more complex situation for sloths and anteaters. Finally, we also demonstrate that the conformation of the cranial vault and nuchal crests as well as the orientation of the posterior part of the petrosal may covary with the LSC orientation in Xenarthra. Possible inferences for the head postures of extinct xenarthrans such as giant ground sloths are discussed in the light of these results.

  19. Gyroscopic stimulation of the semicircular canals during sensory deprivation.

    NASA Technical Reports Server (NTRS)

    Newsom, B. D.; Brady, J. F.; Stumm, J. E.

    1971-01-01

    A static object revolving at a constant velocity is stationary with respect to that environment. When the object is rotated outside the plane of spin, a gyroscopic or cross-coupled acceleration is produced orthogonal to the two planes of rotation. In this situation, a man feels himself moving in a direction other than that which his visual or proprioceptive sensors perceive. The conflict in spatial orientation is the cross-coupled acceleration imposed on the semicircular canals. This perceptual conflict and the thresholds involved were studied by partial isolation of the physiological stimuli through sensory deprivation. Subjects weighted to neutral buoyancy were submerged in 94 F water in the dark. The subjects were then rotated while being revolved about a displaced axis. Thresholds for detection of angular acceleration were higher than those reported in the literature for detection of acceleration of a single plane. This discrepancy may be attributable to the length of time the stimuli are imposed to each of the canals and the cupular response periods.

  20. Lateral semicircular canal fistula in cholesteatoma: diagnosis and management.

    PubMed

    Meyer, Anais; Bouchetemblé, Pierre; Costentin, Bertrand; Dehesdin, Danièle; Lerosey, Yannick; Marie, Jean-Paul

    2016-08-01

    The objective of this retrospective study was to present the authors' experience on the management of labyrinthine fistula secondary to cholesteatoma. 695 patients, who underwent tympanoplasty for cholesteatoma, in a University Hospital between 1993 and 2013 were reviewed, to select only those with labyrinthine fistulas. 42 patients (6%) had cholesteatoma complicated by fistula of the lateral semicircular canal (LSCC). The following data points were collected: symptoms, pre- and postoperative clinical signs, surgeon, CT scan diagnosis, fistula type, surgical technique, preoperative vestibular function and audiometric outcomes. Most frequent symptoms were unspecific, such as otorrhea, hearing loss and dizziness. However, preoperative high-resolution computed tomography predicted fistula in 88 %. Using the Dornhoffer and Milewski classification, 16 cases (38 %) were identified as stage 1, 22 (52 %) as stage II, and 4 (10 %) as stage III. The choice between open or closed surgical procedure was independent of the type of fistulae. The cholesteatoma matrix was completely removed from the fistula and immediately covered by autogenous material. In eight patients (19 %), the canal was drilled with a diamond burr before sealing with autologous tissue. After surgery, hearing was preserved or improved in 76 % of the patients. There was no statistically significant relationship between the extent of the labyrinthine fistula and the hearing outcome. In conclusion, a complete and nontraumatic removal of the matrix cholesteatoma over the fistula in a one-staged procedure and its sealing with bone dust and fascia temporalis, with sometimes exclusion of the LSCC, is a safe and effective procedure to treat labyrinthine fistula.

  1. Gyroscopic stimulation of the semicircular canals during sensory deprivation.

    NASA Technical Reports Server (NTRS)

    Newsom, B. D.; Brady, J. F.; Stumm, J. E.

    1971-01-01

    A static object revolving at a constant velocity is stationary with respect to that environment. When the object is rotated outside the plane of spin, a gyroscopic or cross-coupled acceleration is produced orthogonal to the two planes of rotation. In this situation, a man feels himself moving in a direction other than that which his visual or proprioceptive sensors perceive. The conflict in spatial orientation is the cross-coupled acceleration imposed on the semicircular canals. This perceptual conflict and the thresholds involved were studied by partial isolation of the physiological stimuli through sensory deprivation. Subjects weighted to neutral buoyancy were submerged in 94 F water in the dark. The subjects were then rotated while being revolved about a displaced axis. Thresholds for detection of angular acceleration were higher than those reported in the literature for detection of acceleration of a single plane. This discrepancy may be attributable to the length of time the stimuli are imposed to each of the canals and the cupular response periods.

  2. [Receptor function of the semicircular canals. Part 2: pathophysiology, diseases, clinical findings and treatment aspects].

    PubMed

    Blödow, A; Bloching, M; Hörmann, K; Walther, L E

    2012-03-01

    Perturbation of semicircular canal function may result in a pathological angular vestibulo-ocular reflex (aVOR). The resulting impairment in gaze stabilization is perceived as "vertigo" or "dizziness" and may occur following receptor function impairment of all three semicircular canals. The head impulse test reveals hidden (covert-catchup) or visible (overt-catchup) saccades in disturbances of semicircular function. Most peripheral vestibular disorders can be treated conservatively. There are surgical treatment options for some diseases, such as intractable benign paroxysmal positional vertigo and superior semicircular canal dehiscence. Vestibular training promotes central reorganization of the VOR. Impaired semicircular receptor function, in particular bilateral vestibulopathy, may affect spatial orientation and cognitive processes. Balance prostheses could serve as a replacement for receptors in the future.

  3. Semicircular canal dehiscence among idiopathic intracranial hypertension patients.

    PubMed

    Kuo, Phoebe; Bagwell, Kenneth A; Mongelluzzo, Gino; Schutt, Christopher A; Malhotra, Ajay; Khokhar, Babar; Kveton, John F

    2017-08-22

    The cause of superior semicircular canal dehiscence (SSCD) is unknown. Because of a demonstrated association with tegmental defects and obesity, some have suggested idiopathic intracranial hypertension (IIH) could contribute by eroding the bone over the canal and resulting in SSCD. However, an association between IIH and SSCD has not previously been evaluated. Our objective was to evaluate an association between IIH and SSCD. Retrospective cohort. A retrospective study was performed of opening pressures for consecutive patients presenting at a lumbar puncture clinic between August 2012 and October 2015. Imaging for patients who also had thin-sectioned computed tomography (CT) imaging was reviewed for the presence of radiographic SSCD. Association between IIH and SSCD was evaluated using the Student t test and multivariate logistic regression. One hundred twenty-one patients had both a lumbar puncture performed and thin-sectioned CT imaging available, of which 24 patients (19.8%) met the criteria for IIH with an opening pressure >25 cm H2 O. The remaining 97 patients (80.2%) did not have elevated opening pressures and served as the control cohort. None of the 24 patients with IIH had radiographic SSCD, whereas eight of the 97 patients (8.2%) without IIH had radiographic SSCD. The average opening pressure in patients without radiographic SSCD was 20.2 cm H2 O compared to 19.3 cm H2 O in patients with radiographic SSCD (P = .521). In multivariate logistic regression controlling for age, body mass index, gender, and comorbidities (hypertension, diabetes, hyperlipidemia), opening pressure was not a significant predictor of radiographic SSCD. The results of this retrospective pilot study do not suggest an association between IIH and SSCD. 3b Laryngoscope, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  4. Association Between Tegmen Tympani Status and Superior Semicircular Canal Pattern.

    PubMed

    Whyte, Jaime; Tejedor, Maria Teresa; Fraile, Jesús José; Cisneros, Ana; Crovetto, Rafael; Monteagudo, Luis Vicente; Whyte, Ana; Crovetto, Miguel Angel

    2016-01-01

    Detecting and quantifying the possible association between tegmen tympani (TT) status and superior semicircular canal (SSC) pattern. Observational study. Study conducted in three tertiary Spanish hospitals. Nonselected consecutive patients of all ages (607 temporal bones). Thin-section multidetector row computed axial tomography (CAT scan) of the temporal bones. Thickness of SSC bone coverture adjacent to the middle fossa, and TT status as a dichotomous variable: dehiscence (TTD) or integrity (TTI). The observed SSC patterns were dehiscence (3.79%), papyraceous or thin (11.20%), normal (76.77%), thick (4.94%), and pneumatized (3.29%). The observed TT statuses were TTD (10.87%) and TTI (89.13%). TTD was associated with SSCD and papyraceous patterns, and TTI percentages were higher in normal and thick patterns (χ2 = 11.102; p = 0.001). The TTD probability was estimated as a function of SSC pattern and age by a multivariate binary logistics regression model (χ2 = 45.939; p < 0.001). SSC pattern was significantly associated with TT status. Age influenced this association. The risk for TTD increased by 4.1% per each year of increasing age, did not differ significantly for normal and thick patterns, and increased 12 times and 20 times for papyraceous and SSCD patterns, respectively.

  5. Mechanical amplification by hair cells in the semicircular canals.

    PubMed

    Rabbitt, Richard D; Boyle, Richard; Highstein, Stephen M

    2010-02-23

    Sensory hair cells are the essential mechanotransducers of the inner ear, responsible not only for the transduction of sound and motion stimuli but also, remarkably, for nanomechanical amplification of sensory stimuli. Here we show that semicircular canal hair cells generate a mechanical nonlinearity in vivo that increases sensitivity to angular motion by amplification at low stimulus strengths. Sensitivity at high stimulus strengths is linear and shows no evidence of amplification. Results suggest that the mechanical work done by hair cells contributes approximately 97 zJ/cell of amplification per stimulus cycle, improving sensitivity to angular velocity stimuli below approximately 5 degrees /s (0.3-Hz sinusoidal motion). We further show that mechanical amplification can be inhibited by the brain via activation of efferent synaptic contacts on hair cells. The experimental model was the oyster toadfish, Opsanus tau. Physiological manifestation of mechanical amplification and efferent control in a teleost vestibular organ suggests the active motor process in sensory hair cells is ancestral. The biophysical basis of the motor(s) remains hypothetical, but a key discriminating question may involve how changes in somatic electrical impedance evoked by efferent synaptic action alter function of the motor(s).

  6. Cupula dynamics under caloric stimulation of the semicircular canal

    NASA Astrophysics Data System (ADS)

    Kondrachuk, A. V.; Sirenko, S. P.

    Caloric stimulation of the semicircular canal SC is widely applied in studies of vestibular impairments Barany 1906 suggested that caloric response of SC results from mechanism of endolymph convection due to density changes of endolymph and therefore depends on the action of gravity forces However the Skylab experiments 1983 showed that the caloric reaction of SC can take place even under microgravity The studies of Scherer Clarke 1985 Harada Ariki 1985 Baumgarten et al 1985 considered the thermal expansion of endolymph to be a concurrent mechanism The model of caloric response based on the buoyancy force due to density change in the endolymph induced by thermal stimulation was proposed by Gentine et al 1990 1991 It should be noted that the first qualitative model that took into account the effect of endolymph thermal expansion under local heating to analyze the properties of primary afferents was proposed by Gusev Orlov 1977 However these models failed to answer the question which of the mentioned effects will be dominant under certain conditions The purpose of present study was to account for the expansion and convection of endolymph and to determine under which conditions one mechanism dominates over the other The consideration is based on the following model of SC Kondrachuk Sirenko 1990 an isolated torus filled by a compressible viscous Newton liquid endolymph the torus interior is plugged by an elastic body cupula the cupula surface in contact with endolymph is supposed to be stretched along the

  7. [Defect of the bony roof in the superior semicircular canal and its clinical implications].

    PubMed

    Whyte Orozco, Jaime; Martínez, Claudio; Cisneros, Ana; Obón, Jesús; Gracia-Tello, Borja; Angel Crovetto, Miguel

    2011-01-01

    The aetiology of the superior semicircular canal dehiscence is currently unknown. Our objective was to analyse and discuss different hypotheses about the origin of this pathology. In this study performed on 295 temporal bones, one case of partial alteration of the bony roof in the right superior semicircular canal was described from the anatomical and radiological points of view, and compared with the temporal bone on the other side. Macroscopically, the superior semicircular canal shows deterioration in the bony roof, which consists exclusively of the inner or endosteal layer that separates the canal from the superior semicircular conduct. The Pöschl plane reconstruction showed a whole bony roof, but its thickness decreased from the canal curvature to the defect (from 0.6 to 0.3mm). The presence of partial defects in the bony roof of the superior semicircular canal with absence of the external and middle layers, besides its lesser thickness, makes the canal susceptible to suffering a second event. This could produce its fracture and a dehiscence. Copyright © 2010 Elsevier España, S.L. All rights reserved.

  8. Can lateral semicircular canal dysplasia play a role in the genesis of hyperacusis.

    PubMed

    Modugno, G C; Brandolini, C

    2014-02-01

    Hyperacusis can be a prominent and disabling symptom of superior semicircular canal dehiscence associated with autophony and the Tullio phenomenon. We report three clinical cases characterized by disabling hyperacusis in which semicircular canals dehiscence was excluded by temporal bone high-resolution computed tomography. The images disclosed lateral semicircular canal dysplasia, characterized by a small bony island, and dilatation of both the anterior and the posterior arms of the lateral semicircular canal. Cochleo-vestibular examinations (pure tone audiometry, infra-red videonystagmoscopy, vibration-induced nystagmus test, vestibular evoked myogenic potentials) will also be described. To verify the transtympanic ventilation tube effect, bilateral myringotomies tubes were performed in one patient but no long lasting subjective benefit was noted. Concerning the pathophysiology of this condition, we hypothesized that the increased volume of inner ear liquid can modify the micromechanical function of the cochlea and the labyrinthine hydrodynamics. In conclusion, in the case of specific symptoms, such as hyperacusis, it is important to consider the possibility of an inner ear morphological alteration involving the lateral canal and vestibule structures, as well as the existence of bony semicircular canal dehiscence.

  9. Pseudo-spontaneous nystagmus: a new sign to diagnose the affected side in lateral semicircular canal benign paroxysmal positional vertigo.

    PubMed

    Asprella-Libonati, G

    2008-04-01

    Early diagnosis of the affected side in Lateral Semicircular Canal Benign Paroxysmal Positional Vertigo is important in effectively applying treatment manoeuvres. This study was performed to examine the frequency of a new clinical sign, pseudo-spontaneous nystagmus, in a large cohort of patients with Lateral Semicircular Canal Benign Paroxysmal Positional Vertigo, comparing its efficacy in the identification of the involved side with that of other diagnostic signs, seated supine positioning nystagmus, and the intensity of the nystagmus evoked by the head yaw test in the supine position. Overall, 293 patients affected by Lateral Semicircular Canal Benign Paroxysmal Positional Vertigo (197 geotropic and 96 apogeotropic forms) were examined. Pseudo-spontaneous nystagmus was observed in 222 patients (76%). After a very slow, repeated horizontal rotation of the head, in the seated position, this percentage increased to 96% (281 patients). The pseudo-spontaneous nystagmus and the seated supine positioning nystagmus always beat in the same direction and both were in accordance in identifying the affected side with the nystagmus evoked by the head yaw test. The differential diagnosis between spontaneous nystagmus and pseudo-spontaneous nystagmus is easily achieved with the head pitch test in the sitting position: the pseudo-spontaneous nystagmus disappears with the head bent forward 30 degrees (neutral position), it reverses its direction with the head bent 60 degrees forward, it returns visible bringing the head in axis with the body and increases its intensity extending the head about 30 degrees backwards. Pseudo-spontaneous nystagmus is an important sign for determining the affected ear in Lateral Semicircular Canal Benign Paroxysmal Positional Vertigo. Early identification of the affected side improves efficacy of treatment and compliance of patients.

  10. Mechanism of posterior semicircular canal stimulation in patients with benign paroxysmal positional vertigo.

    PubMed

    Honrubia, V; House, M

    2001-01-01

    A quantitative study of the stimuli and vestibulo-ocular response associated with benign paroxysmal positional vertigo (BPPV) was made to test and further develop the canalithiasis theory of BPPV. The angular velocities of the head in the planes of the semicircular canals during the Dix-Hallpike test were measured in four healthy subjects using electromagnetic sensors to record the position of the head in a six degrees of freedom paradigm. Next, the nystagmus reactions in seven patients diagnosed with idiopathic BPPV were recorded with video-oculography. The characteristics of the vestibulo-ocular reflex (VOR) response were analyzed using three-dimensional vector techniques. The angular velocity of the head was primarily, but not exclusively, in the plane of the posterior semicircular canal (PSC) in question. Both the anterior and horizontal canals were also stimulated by a lesser degree. The duration of the motion stimulus in the PSC was < 1.3 s with peak angular velocities of 150 deg/s. The eye response in BPPV patients began 4 s after the test and had a duration of 15-20 s. Peak slow-component eye velocities of about 42 deg/s were reached 3-5 s after onset of nystagmus. The motion of the eye, as predicted by the cupulolithiasis theory, is disconjugated and has torsional, vertical, and horizontal components. In the eye ipsilateral to the tested ear it is primarily torsional (0.80, 0.54, 0.16) and in the contralateral eye it is mainly vertical (0.57, 0.73, 0.08). These results suggest that particles, initially resting on the floor of the cupula dome in the PSC, are perturbed by the Dix-Hallpike test and disperse freely into the endolymph where they are propelled by gravity into the canal lumen. This creates abnormal pressure on the cupula and the specific VOR activation of the ipsilateral superior oblique and the contralateral inferior rectus muscles, whose force vectors are indistinguishable from the measured eye motion vectors. The estimated pressure exerted on

  11. Ontogenetic explanation for tegmen tympani dehiscence and superior semicircular canal dehiscence association.

    PubMed

    Fraile Rodrigo, Jesús José; Cisneros, Ana I; Obón, Jesús; Yus, Carmen; Crovetto, Rafael; Crovetto, Miguel A; Whyte, Jaime

    2016-01-01

    To analyze the ontogeny of the superior semicircular canal and tegmen tympani and determine if there are common embryological factors explaining both associated dehiscence. We analyzed 77 human embryological series aged between 6 weeks and newborn. Preparations were serially cut and stained with Masson's trichrome technique. The tegmental prolongation of tegmen tympani and superior semicircular canal originate from the same structure, the otic capsule, and have the same type of endochondral ossification; while the extension of the squamous prolongation of tegmen tympani runs from the temporal squama and ossification is directly of intramembranous type. The nuclei of ossification of the superior and external semicircular canals and accessory of tegmen collaborate in the ossification of the tegmental extension and by growth extend to the tegmental prolongation. This fact plus the fact that both structures share a common layer of external periosteum could explain the coexistence of lack of bone coverage in tegmen and superior semicircular canal. The development of the semicircular canal and tegmen tympani could explain the causes of the association of both dehiscences. Copyright © 2015 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

  12. [Functional analysis of the vertical semicircular canal using vertical plane swing test and study of its normal values].

    PubMed

    Peng, Xin; Sun, Qing; Li, Na; Yang, Li-jun; Dai, Jing; Shan, Xi-zheng

    2012-01-01

    The purpose of this study was to set up a method to analyze the vertical semicircular canal function and study the normal values of the vertical semicircular canal function using the vertical plane swing test. A prospective analysis of 100 normal persons (aged from 18 to 59 years), who were treated by using the vertical plane swing test with the newly developed automatic vestibular function diagnosis and therapy system (SRM-IV). These persons were rotated 180° at a sinusoidal speed (acceleration 45°/s, maximum speed 90°/s) in the vertical semicircular canal plane. Using a PC, evoked vertical nystagmus was analyzed in order to evaluate the excitability of vertical semicircular canals, including the number and the duration of nystagmus, the slow phase velocity and other parameters. Meanwhile, the all persons were divided into two groups, order and younger than 45 years respectively. In the test procedure, with the two pairs of the right anterior vertical semicircular canal and left posterior vertical semicircular canal (RALP) as well as the left anterior vertical semicircular canal and the rear right vertical semicircular canals (LARP), the average slow phase velocity of the vertical nystagmus and the canal paresis (CP) of the two pairs of vertical semicircular canals were calculated using PC and SPSS13.0 software for statistical analysis. There was no significant difference between the two groups (P > 0.05). The general CP of RALP was 10.2% ± 7.1%, and LARP was 10.4% ± 6.2%. The normal CP range of the vertical semicircular canal in the health group was identified (idea: ≤ 20%; normal high: 20% - 25%). The 180° vertical plane sinusoidal swing method is effective in functional analysis of the vertical semicircular canal, it is expected to be reliably used in clinical treatment.

  13. Interaction between otolith organ and semicircular canal vestibulo-ocular reflexes during eccentric rotation in humans.

    PubMed

    Gianna-Poulin, Claire C; Peterka, Robert J

    2008-03-01

    Controversy remains about the linearity of the interaction between horizontal semicircular canal and otolith organ vestibulo-ocular reflexes (VORs) in the generation of horizontal eye movements during head movements including both rotational and translational components. We used three eccentric rotation techniques to investigate this interaction in human subjects: (1) the tangential interaural acceleration was varied using three head positions (on-axis, 25 and 40 cm ahead of the rotational axis), while angular head velocity remained unchanged; (2) the magnitude of the angular head velocity was varied with head eccentricity to keep the tangential interaural acceleration unchanged; (3) the subject's head was oriented either upright or 90 degrees forward from upright (nose-down). Experiments were performed in complete darkness with the subjects remembering a close earth-fixed target (20 cm distant) while being rotated at 1.2 and 1.8 Hz. Our data showed that the translational component of the VOR evoked during eccentric yaw rotation increased proportionally with an increase in head eccentricity, i.e. with tangential acceleration. We also found that the translational component of the VOR was equal for motion stimuli producing identical interaural tangential accelerations even when angular velocities differed. In addition, we found that the translational component of the VOR evoked during head upright eccentric rotation was equal to the translational VOR evoked during nose-down rotation for a given stimulus and head eccentricity. We conclude that these three findings are in agreement with what would be expected from a linear interaction (i.e. algebraic summation) between otolith organ and horizontal canal VORs for the generation of horizontal compensatory eye movements during head motion.

  14. Tympanometric findings in superior semicircular canal dehiscence syndrome.

    PubMed

    Castellucci, A; Brandolini, C; Piras, G; Modugno, G C

    2013-04-01

    The diagnostic role of audio-impedancemetry in superior semicircular canal dehiscence (SSCD) disease is well known. In particular, since the first reports, the presence of evoked acoustic reflexes has represented a determining instrumental exhibit in differential diagnosis with other middle ear pathologies that are responsible for a mild-low frequencies air-bone gap (ABG). Even though high resolution computed tomography (HRCT) completed by parasagittal reformatted images still represents the diagnostic gold standard, several instrumental tests can support a suspect of labyrinthine capsule dehiscence when "suggestive" symptoms occur. Objective and subjective audiometry often represents the starting point of the diagnostic course aimed at investigating the cause responsible for the so-called "intra-labyrinthine conductive hearing loss". The purpose of this study is to evaluate the role of tympanometry, in particular of the inter-aural asymmetry ratio in peak compliance as a function of different mild-low frequencies ABG on the affected side, in the diagnostic work-up in patients with unilateral SSCD. The working hypothesis is that an increase in admittance of the "inner-middle ear" conduction system due to a "third mobile window" could be detected by tympanometry. A retrospective review of the clinical records of 45 patients with unilateral dehiscence selected from a pool of 140 subjects diagnosed with SSCD at our institution from 2003 to 2011 was performed. Values of ABG amplitude on the dehiscent side and tympanometric measurements of both ears were collected for each patient in the study group (n = 45). An asymmetry between tympanometric peak compliance of the involved side and that of the contralateral side was investigated by calculating the inter-aural difference and the asymmetry ratio of compliance at the eardrum. A statistically significant correlation (p = 0.015 by Fisher's test) between an asymmetry ratio ≥ 14% in favour of the pathologic ear and an ABG

  15. Turning semicircular canal function on its head: dinosaurs and a novel vestibular analysis.

    PubMed

    Georgi, Justin A; Sipla, Justin S; Forster, Catherine A

    2013-01-01

    Previous investigations have correlated vestibular function to locomotion in vertebrates by scaling semicircular duct radius of curvature to body mass. However, this method fails to discriminate bipedal from quadrupedal non-avian dinosaurs. Because they exhibit a broad range of relative head sizes, we use dinosaurs to test the hypothesis that semicircular ducts scale more closely with head size. Comparing the area enclosed by each semicircular canal to estimated body mass and to two different measures of head size, skull length and estimated head mass, reveals significant patterns that corroborate a connection between physical parameters of the head and semicircular canal morphology. Head mass more strongly correlates with anterior semicircular canal size than does body mass and statistically separates bipedal from quadrupedal taxa, with bipeds exhibiting relatively larger canals. This morphologic dichotomy likely reflects adaptations of the vestibular system to stability demands associated with terrestrial locomotion on two, versus four, feet. This new method has implications for reinterpreting previous studies and informing future studies on the connection between locomotion type and vestibular function.

  16. Turning Semicircular Canal Function on Its Head: Dinosaurs and a Novel Vestibular Analysis

    PubMed Central

    Georgi, Justin A.; Sipla, Justin S.; Forster, Catherine A.

    2013-01-01

    Previous investigations have correlated vestibular function to locomotion in vertebrates by scaling semicircular duct radius of curvature to body mass. However, this method fails to discriminate bipedal from quadrupedal non-avian dinosaurs. Because they exhibit a broad range of relative head sizes, we use dinosaurs to test the hypothesis that semicircular ducts scale more closely with head size. Comparing the area enclosed by each semicircular canal to estimated body mass and to two different measures of head size, skull length and estimated head mass, reveals significant patterns that corroborate a connection between physical parameters of the head and semicircular canal morphology. Head mass more strongly correlates with anterior semicircular canal size than does body mass and statistically separates bipedal from quadrupedal taxa, with bipeds exhibiting relatively larger canals. This morphologic dichotomy likely reflects adaptations of the vestibular system to stability demands associated with terrestrial locomotion on two, versus four, feet. This new method has implications for reinterpreting previous studies and informing future studies on the connection between locomotion type and vestibular function. PMID:23516495

  17. New Treatment Strategy for Apogeotropic Horizontal Canal Benign Paroxysmal Positional Vertigo

    PubMed Central

    e Maia, Francisco Zuma

    2016-01-01

    The apogeotropic variant of horizontal semicircular canal benign paroxysmal positional vertigo (HC-BPPV) is attributed to canalithiasis of the anterior arm or cupulolithiasis. Despite some therapeutic maneuvers, I propose a new treatment strategy for apogeotropic HC-BPPV that is designed to detach both the otoconial debris from the anterior arm of the semicircular canal and the debris that is attached to the utricular side of the cupula using inertia and gravity and based on simulations with a 3D biomechanical model. PMID:27942374

  18. Integration of semicircular canal and otolith information for multisensory orientation stimuli

    NASA Technical Reports Server (NTRS)

    Ormsby, C. C.; Young, L. R.

    1977-01-01

    This paper presents a model for the perception of dynamic orientation resulting from stimuli which involve both the otoliths and the semicircular canals. The model was applied to several multisensory stimuli and its predictions evaluated. In all cases, the model predictions were in substantial agreement with the known illusions or with the relevant experimental data.

  19. A Generalized Transfer Function for Describing Mechanoneural Semicircular-Canal Dynamics,

    DTIC Science & Technology

    1980-01-01

    I ,F the membranous camel ; A is the elavtlc-restoring moment per unit angllar dispIsooment of Ihe end,,lymph relitive to the membranous ampuliary...Springer (in press), 1980. 9 CRUM4 BROWN, A. On tbr, V 1 1 atad the anatomy and physiology of the semicircular canals of the inner ear. !j. Anss? -’ 1874

  20. Use of Steinhausen's model for describing periodic Coriolis star nystagmus. [biodynamics of semicircular canal system

    NASA Technical Reports Server (NTRS)

    Valentinuzzi, M.

    1973-01-01

    Phase lag, maximal slow phase velocity, and beat frequency were measured in periodic Coriolis star nystagmus. The results have been described by Steinhausen's model of the semicircular canal system. Estimates of the biophysical constants have been obtained. It is concluded that this model is a good functional approximation for describing, and also for interpreting, the behavior of the system.

  1. [Dehiscence of the anterior semicircular canal and otosclerosis: a case report].

    PubMed

    Nguyen, D Q; Morel, N; Dumas, G; Boubagra, K; Schmerber, S

    2006-01-01

    The dehiscence of the anterior semicircular canal is a new clinical entity, it is necessary to consider this when a gusher occurs during stapedial surgery. We report a rare case of dehiscence of the anterior canal associated with otosclerosis. This was revealed by a gusher during the initial stapedectomy. At 3 months, an obliteration of the dehiscence was necessary by middle cranial fossa approach (persistant vestibular symptoms), seven months later. Revision stapedial surgery resulted in complete closure of the air-bone-gap. High resolution CT scans of the temporal bone are the key to diagnosis. It is necessary to appreciate this pathology with advances in canal and vestibular surgery.

  2. Mathematical Model of the Cupula-Endolymph System with Morphological Parameters for the Axolotl (Ambystoma tigrinum) Semicircular Canals

    PubMed Central

    Vega, Rosario; Alexandrov, Vladimir V; Alexandrova, Tamara B; Soto, Enrique

    2008-01-01

    By combining mathematical methods with the morphological analysis of the semicircular canals of the axolotl (Ambystoma tigrinum), a system of differential equations describing the mechanical coupling in the semicircular canals was obtained. The coefficients of this system have an explicit physiological meaning that allows for the introduction of morphological and dynamical parameters directly into the differential equations. The cupula of the semicircular canals was modeled both as a piston and as a membrane (diaphragm like), and the duct canals as toroids with two main regions: i) the semicircular canal duct and, ii) a larger diameter region corresponding to the ampulla and the utricle. The endolymph motion was described by the Navier-Stokes equations. The analysis of the model demonstrated that cupular behavior dynamics under periodic stimulation is equivalent in both the piston and the membrane cupular models, thus a general model in which the detailed cupular structure is not relevant was derived. PMID:19593455

  3. Mathematical Model of the Cupula-Endolymph System with Morphological Parameters for the Axolotl (Ambystoma tigrinum) Semicircular Canals.

    PubMed

    Vega, Rosario; Alexandrov, Vladimir V; Alexandrova, Tamara B; Soto, Enrique

    2008-08-26

    By combining mathematical methods with the morphological analysis of the semicircular canals of the axolotl (Ambystoma tigrinum), a system of differential equations describing the mechanical coupling in the semicircular canals was obtained. The coefficients of this system have an explicit physiological meaning that allows for the introduction of morphological and dynamical parameters directly into the differential equations. The cupula of the semicircular canals was modeled both as a piston and as a membrane (diaphragm like), and the duct canals as toroids with two main regions: i) the semicircular canal duct and, ii) a larger diameter region corresponding to the ampulla and the utricle. The endolymph motion was described by the Navier-Stokes equations. The analysis of the model demonstrated that cupular behavior dynamics under periodic stimulation is equivalent in both the piston and the membrane cupular models, thus a general model in which the detailed cupular structure is not relevant was derived.

  4. Bilateral posterior semicircular canal aplasia and atypical paroxysmal positional vertigo: a case report.

    PubMed

    Walther, L E; Nath, V; Krombach, G A; Di Martino, E

    2008-04-01

    Isolated congenital malformations of semicircular canals are rare abnormalities. Most inner ear abnormalities occur in syndromes and are associated with hearing loss. Unilateral or bilateral single aplasia of one semicircular canal does not usually result in vertigo, but these become clinically important if there are clinical complaints of vertigo. Computed tomography imaging and high resolution magnetic resonance imaging may reveal inner ear abnormalities. The case is presented here of a 46-year-old male with a 10-year history of recurrent positional vertigo with strong onset when changing position to the left side. Magnetic resonance imaging of the inner ear showed a bilateral posterior semicircular canal aplasia as well as an enlarged vestibule on both sides. Dix-Hallpike positional manoeuvre revealed a positional nystagmus in the left head-hanging position of short duration and latency of a few seconds. When rising, vertigo occurred, but no nystagmus was visible. The fast phase of the nystagmus was mainly vertical down-beating with a slight torsional component to the uppermost ear. Although benign paroxysmal vertigo of the anterior canal was suspected, physical therapy was not effective using a modified liberatory manoeuvre. Brandt-Daroff therapy was effective permanently.

  5. Lateral Semicircular Canal Asymmetry in Idiopathic Scoliosis: An Early Link between Biomechanical, Hormonal and Neurosensory Theories?

    PubMed Central

    Hitier, Martin; Hamon, Michèle; Denise, Pierre; Lacoudre, Julien; Thenint, Marie-Aude; Mallet, Jean-François; Moreau, Sylvain; Quarck, Gaëlle

    2015-01-01

    Introduction Despite its high incidence and severe morbidity, the physiopathogenesis of adolescent idiopathic scoliosis (AIS) is still unknown. Here, we looked for early anomalies in AIS which are likely to be the cause of spinal deformity and could also be targeted by early treatments. We focused on the vestibular system, which is suspected of acting in AIS pathogenesis and which exhibits an end organ with size and shape fixed before birth. We hypothesize that, in adolescents with idiopathic scoliosis, vestibular morphological anomalies were already present at birth and could possibly have caused other abnormalities. Materials and Methods The vestibular organ of 18 adolescents with AIS and 9 controls were evaluated with MRI in a prospective case controlled study. We studied lateral semicircular canal orientation and the three semicircular canal positions relative to the midline. Lateral semicircular canal function was also evaluated by vestibulonystagmography after bithermal caloric stimulation. Results The left lateral semicircular canal was more vertical and further from the midline in AIS (p = 0.01) and these two parameters were highly correlated (r = -0.6; p = 0.02). These morphological anomalies were associated with functional anomalies in AIS (lower excitability, higher canal paresis), but were not significantly different from controls (p>0.05). Conclusion Adolescents with idiopathic scoliosis exhibit morphological vestibular asymmetry, probably determined well before birth. Since the vestibular system influences the vestibulospinal pathway, the hypothalamus, and the cerebellum, this indicates that the vestibular system is a possible cause of later morphological, hormonal and neurosensory anomalies observed in AIS. Moreover, the simple lateral SCC MRI measurement demonstrated here could be used for early detection of AIS, selection of children for close follow-up, and initiation of preventive treatment before spinal deformity occurs. PMID:26186348

  6. Analysis of intraindividual and intraspecific variation in semicircular canal dimensions using high-resolution x-ray computed tomography.

    PubMed

    Welker, Kelli L; Orkin, Joseph D; Ryan, Timothy M

    2009-10-01

    The semicircular canal system tracks head rotation and provides sensory input for the reflexive stabilization of gaze and posture. The purpose of this study was to investigate the intraspecific and intraindividual variation in the size of the three semicircular canals. The right and left temporal bones were extracted from 31 individuals of the short-tailed shrew (Blarina brevicauda) and scanned on a high-resolution x-ray computed tomography system. The radius of curvature was calculated for each of the three semicircular canals for each side. Paired t-tests and independent sample t-tests indicated no significant differences in canal size between the right and left canals of the same individuals or between those of males and females of the same species. Pearson product moment correlation analyses demonstrated that there was no significant correlation between canal size and body mass in this sample.

  7. Analysis of intraindividual and intraspecific variation in semicircular canal dimensions using high-resolution x-ray computed tomography

    PubMed Central

    Welker, Kelli L; Orkin, Joseph D; Ryan, Timothy M

    2009-01-01

    The semicircular canal system tracks head rotation and provides sensory input for the reflexive stabilization of gaze and posture. The purpose of this study was to investigate the intraspecific and intraindividual variation in the size of the three semicircular canals. The right and left temporal bones were extracted from 31 individuals of the short-tailed shrew (Blarina brevicauda) and scanned on a high-resolution x-ray computed tomography system. The radius of curvature was calculated for each of the three semicircular canals for each side. Paired t-tests and independent sample t-tests indicated no significant differences in canal size between the right and left canals of the same individuals or between those of males and females of the same species. Pearson product moment correlation analyses demonstrated that there was no significant correlation between canal size and body mass in this sample. PMID:19619167

  8. A geometric analysis of semicircular canals and induced activity in their peripheral afferents in the rhesus monkey

    NASA Technical Reports Server (NTRS)

    Reisine, H.; Simpson, J. I.; Henn, V.

    1988-01-01

    Experiments were carried out to determine anatomically the planes of the semicircular canals of two juvenile rhesus monkeys, using plastic casts of the semicircular canals, and the anatomical measurements were related to the directional coding of neural signals transmitted by primary afferents innervating the same simicircular canals. In the experiments, animals were prepared for monitoring the eye position by the implantation of silver-silver chloride electrodes into the bony orbit. Following the recording of semicircular canal afferent activity, the animals were sacrificed; plastic casting resin was injected into the bony canals; and, when the temporal bone was demineralized and removed, the coordinates of points spaced along the circumference of the canal casts were measured. A comparison of the sensitivity vectors determined in these experiments and the anatomical measures showed that the average difference between a sensitivity vector and its respective normal vector was 6.3 deg.

  9. Behavior of the Posterior Semicircular Canal After Dix-Hallpike Maneuver

    PubMed Central

    e Maia, Francisco Carlos Zuma; Albernaz, Pedro Luiz Mangabeira; Cal, Renato Valério

    2016-01-01

    The objective of the present study is to analyze the quantitative vestibulo-ocular responses in a group of patients with benign paroxysmal positional vertigo (BPPV) canalolithiasis and compare these data with the data of the tridimensional biomechanical model. This study was conducted on 70 patients that presented idiopathic posterior semicircular canal canalolithiasis. The diagnosis was obtained by Dix-Hallpike maneuvers recorded by videonystagmograph. The present study demonstrates that there is a significant correlation between the intensity of the nystagmus and its latency in cases of BPPV-idiopathic posterior semicircular canal canalolithiasis type. These findings are in agreement with those obtained in a tridimensional biomechanical model and are not related to the patients’ age. PMID:27588161

  10. Persistent Down-Beating Torsional Positional Nystagmus: Posterior Semicircular Canal Light Cupula?

    PubMed Central

    Otsuka, Koji

    2016-01-01

    A 16-year-old boy with rotatory positional vertigo and nausea, particularly when lying down, visited our clinic. Initially, we observed vertical/torsional (downward/leftward) nystagmus in the supine position, and it did not diminish. In the sitting position, nystagmus was not provoked. Neurological examinations were normal. We speculated that persistent torsional down-beating nystagmus was caused by the light cupula of the posterior semicircular canal. This case provides novel insights into the light cupula pathophysiology. PMID:27668113

  11. Superior semicircular canal dehiscence associated with external, middle, and inner ear abnormalities.

    PubMed

    Wang, Jenny R; Parnes, Lorne S

    2010-02-01

    We report a case of bilateral superior semicircular canal dehiscence (SSCD) in a 38-year-old man who presented with congenital hearing loss without vestibular symptoms. This case is unusual due to the association of SSCD with multiple congenital anomalies of the external, middle, and inner ears, but without any other craniofacial or systemic developmental anomalies. Findings of multiple malformations of temporal bone structures in this case lend support to the theory that SSCD may have an underlying developmental or congenital etiology.

  12. Semicircular canals and agility: the influence of size and shape measures

    PubMed Central

    Cox, Philip G; Jeffery, Nathan

    2010-01-01

    The semicircular canals of the inner ear sense angular accelerations and decelerations of the head and enable co-ordination of posture and body movement, as well as visual stability. Differences of agility and spatial sensitivity among species have been linked to interspecific differences in the relative size of the canals, particularly the radius of curvature (R) and the ratio of the canal plane area to streamline length (P/L). Here we investigate the scaling relationships of these two size variables and also out-of-plane torsion in the three semicircular canals (anterior, posterior and lateral), in order to assess which is more closely correlated with body size and locomotor agility. Measurements were computed from 3D landmarks taken from magnetic resonance images of a diverse sample of placental mammals encompassing 16 eutherian orders. Body masses were collected from the literature and an agility score was assigned to each species. The R and P/L of all three semicircular canals were found to have highly significant positive correlations with each other and no statistical difference was found between the slope of 2P/L against R and 1. This indicated that, contrary to initial hypotheses, there is little difference between 2P/L and R as measures of semicircular canal size. A measure of the in-plane circularity of the canal was obtained by dividing 2P/L by R and out-of-plane torsion was measured as angular deviation from a plane of best fit. It was predicted that deviations from in-plane and out-of-plane circularity would increase at small body size due to the constraints of fitting a proportionately larger canal into a smaller petrous bone. However, neither measurement was found to have a significant correlation with body mass, indicating that deviations from circularity (both in-plane and out-of-plane) are not sufficient to alter P/L to an extent that would impact the sensitivity of the canals. 2P/L and R were both shown to be significantly correlated with

  13. Semicircular canal, saccular and utricular function in patients with bilateral vestibulopathy: analysis based on etiology

    PubMed Central

    Bremova, Tatiana; Kremmyda, Olympia; Strupp, Michael

    2014-01-01

    The diagnosis of bilateral vestibulopathy (BV) is typically established based on bilateral semicircular canal dysfunction. The degree to which both otolith organs—the saccule and utricle—are also impaired in BV is not wellestablished, particularly with respect to the etiology and severity of BV. The aim of this study was to evaluate semicircular canal, saccular and utricular function in patients with BV due to aminoglycoside ototoxicity and bilateral Menière’s disease, and with different severities of BV. Caloric and head impulse testing were used as measures of canal function. Cervical vestibular-evoked myogenic potentials (cVEMP) and ocular VEMPs (oVEMP) were used as measures of saccular and utricular function, respectively. We enrolled 34 patients with BV and 55 controls in a prospective case–control study. Patients with BV were less likely to have saccular (61 %) or utricular (64 %) dysfunction relative to canal dysfunction (100 %). Utricular function differed significantly between patients by etiologic group: the poorest function was found in patients with BV due to aminoglycoside toxicity, and the best function in Menière’s disease patients. Canal and saccular function did not vary according to etiology. Further, utricular but not saccular function was significantly correlated with canal function. Saccular and utricular function had the strongest association with Dizziness Handicap Inventory scores relative to canal function. These data suggest that when a patient with BV is identified in a clinical context, oVEMP testing is the most sensitive test in distinguishing between aminoglycoside toxicity and bilateral Menière’s disease. Both cVEMP and oVEMP testing may be considered to evaluate the functional impact on the patient. PMID:23104126

  14. The neuronal organization of horizontal semicircular canalactivated inhibitory vestibulocollic neurons in the cat.

    PubMed

    Isu, N; Sakuma, A; Hiranuma, K; Uchino, H; Sasaki, S; Imagawa, M; Uchino, Y

    1991-01-01

    1. The somatic location and axonal projections of inhibitory vestibular nucleus neurons activated by the horizontal semicircular canal nerve (HCN) were studied in anesthetized cats. Cats were anesthetized with ketamine hydrochloride and pentobarbital sodium. 2. Intracellular recordings were obtained from 11 neck extensor motoneurons which were identified by antidromic activation from the dosal rami (DR) in the C1 segment. Stimulation of the ipsilateral (i-) HCN and the ipsilateral abducens (AB) nucleus evoked IPSPs in the motoneurons. These IPSPs were fully or partially occluded when they were evoked simultaneously. 3. Intracellular recordings were obtained from 8 AB motoneurons. Stimulation of the i-HCN and the i-C1DR motoneuron pool evoked IPSPs in the AB motoneurons. These IPSPs were also partially occluded when they were evoked simultaneously, which implied that some HCN-activated neurons inhibit both i-AB motoneurons and ipsilateral neck motoneurons. 4. Unit activity was extracellularly recorded from 30 vestibular neurons that were activated monosynaptically by i-HCN stimulation. Their axonal projections were determined by stimulating the i-AB nucleus and the i-C1DR motoneuron pool. Eight neurons were activated by both stimuli, and were termed vestibulooculo-collic (VOC) neurons. Their axonal branching was examined by means of local stimulation in and around the i-AB nucleus and the i-C1DR motoneuron pool. Eighteen neurons were antidromically activated from the i-C1DR motoneuron pool but not from the i-AB nucleus. These were termed vestibulo-collic (VC) neurons. Four neurons were activated from the i-AB nucleus but not from the ventral funiculus in the C1 segment, and were termed vestibulo-ocular (VO) neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Functional recovery of anterior semicircular canal afferents following hair cell regeneration in birds

    NASA Technical Reports Server (NTRS)

    Boyle, Richard; Highstein, Stephen M.; Carey, John P.; Xu, Jinping

    2002-01-01

    Streptomycin sulfate (1.2 g/kg i.m.) was administered for 5 consecutive days to 5-7-day-old white Leghorn chicks; this causes damage to semicircular canal hair cells that ultimately regenerate to reform the sensory epithelium. During the recovery period, electrophysiological recordings were taken sequentially from anterior semicircular canal primary afferents using an indentation stimulus of the canal that has been shown to mimic rotational stimulation. Chicks were assigned to an early (14-18 days; n = 8), intermediate (28-34 days; n = 5), and late (38-58 days; n = 4) period based on days after treatment. Seven untreated chicks, 15-67 days old, provided control data. An absence of background and indent-induced discharge was the prominent feature of afferents in the early period: only "silent" afferents were encountered in 5/8 experiments. In several of these chicks, fascicles of afferent fibers were seen extending up to the epithelium that was void of hair cells, and intra- and extracellular biocytin labeling revealed afferent processes penetrating into the supporting cell layer of the crista. In 3/8 chicks 74 afferents could be characterized, and they significantly differed from controls (n = 130) by having a lower discharge rate and a negligible response to canal stimulation. In the intermediate period there was considerable variability in discharge properties of 121 afferents, but as a whole the number of "silent" fibers in the canal nerve diminished, the background rate increased, and a response to canal stimulation detected. Individually biocytin-labeled afferents had normal-appearing terminal specializations in the sensory epithelium by 28 days poststreptomycin. In the late period, afferents (n = 58) remained significantly different from controls in background discharge properties and response gain. The evidence suggests that a considerable amount of variability exists between chicks in the return of vestibular afferent function following ototoxic injury and

  16. Functional recovery of anterior semicircular canal afferents following hair cell regeneration in birds

    NASA Technical Reports Server (NTRS)

    Boyle, Richard; Highstein, Stephen M.; Carey, John P.; Xu, Jinping

    2002-01-01

    Streptomycin sulfate (1.2 g/kg i.m.) was administered for 5 consecutive days to 5-7-day-old white Leghorn chicks; this causes damage to semicircular canal hair cells that ultimately regenerate to reform the sensory epithelium. During the recovery period, electrophysiological recordings were taken sequentially from anterior semicircular canal primary afferents using an indentation stimulus of the canal that has been shown to mimic rotational stimulation. Chicks were assigned to an early (14-18 days; n = 8), intermediate (28-34 days; n = 5), and late (38-58 days; n = 4) period based on days after treatment. Seven untreated chicks, 15-67 days old, provided control data. An absence of background and indent-induced discharge was the prominent feature of afferents in the early period: only "silent" afferents were encountered in 5/8 experiments. In several of these chicks, fascicles of afferent fibers were seen extending up to the epithelium that was void of hair cells, and intra- and extracellular biocytin labeling revealed afferent processes penetrating into the supporting cell layer of the crista. In 3/8 chicks 74 afferents could be characterized, and they significantly differed from controls (n = 130) by having a lower discharge rate and a negligible response to canal stimulation. In the intermediate period there was considerable variability in discharge properties of 121 afferents, but as a whole the number of "silent" fibers in the canal nerve diminished, the background rate increased, and a response to canal stimulation detected. Individually biocytin-labeled afferents had normal-appearing terminal specializations in the sensory epithelium by 28 days poststreptomycin. In the late period, afferents (n = 58) remained significantly different from controls in background discharge properties and response gain. The evidence suggests that a considerable amount of variability exists between chicks in the return of vestibular afferent function following ototoxic injury and

  17. Sudden hearing loss with simultaneous posterior semicircular canal BPPV: possible etiology and clinical implications.

    PubMed

    El-Saied, Sabri; Joshua, Ben-Zion; Segal, Nili; Kraus, Mordechai; Kaplan, Daniel M

    2014-01-01

    The objectives of this study were to describe the clinical course and outcome of patients with sudden sensorineural hearing loss (SSNHL) in conjunction with benign paroxysmal positional vertigo (BPPV), and hypothesize the possible pathophysiology of this entity. Retrospective study of all patients with evidence of SSNHL with any type of BPPV between 2008 and 2012. Tertiary care university hospital. Five patients aged 56 to 71 were diagnosed with unilateral profound SSNHL and BPPV. Neurotologic examination revealed an ipsilateral torsional, up-beating nystagmus on Dix-Hallpike exam. Severe or profound ipsilateral-sensorineural hearing loss was recognized on audiometry. The rest of the exam was normal; this was in keeping with the diagnosis of SSNHL with ipsilateral posterior semicircular canal BPPV. All patients were treated with a modified Epley maneuver; oral steroids were administered for two weeks. In all cases vertigo resolved and the Dix-Hallpike exam became normal within several weeks. However, the hearing loss remained unchanged in two patients. Magnetic resonance imaging of the head was normal and ENG caloric test demonstrated mild ipsilateral canal paresis in two patients. 1. Patients with SSNHL and BPPV can have a variable clinical course and outcome. This entity may be quite common, but the diagnosis of BPPV can be missed if a complete neurological physical examination is not performed. 2. Arterial occlusions or selective multiple vascular or neural involvement may explain the pathophysiology of SSNHL with BPPV of the posterior semicircular canal. © 2014.

  18. Distinct functions for Netrin-1 in chicken and murine semicircular canal morphogenesis.

    PubMed

    Nishitani, Allison M; Ohta, Sho; Yung, Andrea R; Del Rio, Tony; Gordon, Michael I; Abraira, Victoria E; Avilés, Evelyn C; Schoenwolf, Gary C; Fekete, Donna M; Goodrich, Lisa V

    2017-08-29

    The vestibular system of the inner ear detects head position using three orthogonally oriented semicircular canals; even slight changes in their shape and orientation can cause debilitating behavioral defects. During development, the canals are sculpted from pouches that protrude from the otic vesicle, the embryonic anlage of the inner ear. In the center of each pouch, a fusion plate forms where cells lose their epithelial morphology and the basement membrane breaks down. Cells in the fusing epithelia intercalate and are removed, creating a canal. In mice, fusion depends on the secreted protein Netrin-1, which is necessary for basement membrane breakdown, although the underlying molecular mechanism is unknown. Using gain-of-function approaches, we found that overexpression of Netrin-1 in the chick otic vesicle prevented canal fusion by inhibiting apoptosis. In contrast, ectopic expression of the same chicken Netrin-1 in the mouse otic vesicle, where apoptosis is less prominent, resulted in canal truncation. These findings highlight the importance of apoptosis for tissue morphogenesis and suggest that Netrin-1 may play divergent cellular roles despite its conserved expression during canal morphogenesis in chicken and mouse. © 2017. Published by The Company of Biologists Ltd.

  19. Influence of aging and menopause in the origin of the superior semicircular canal dehiscence.

    PubMed

    Crovetto, Miguel Angel; Whyte, Jaime; Rodriguez, Olivia M; Lecumberri, Iñigo; Martinez, Claudio; Fernandez, Carmen; Crovetto, Rafael; Municio, Antonio; Vrotsou, Kalliopi

    2012-06-01

    Determine if aging and menopause, known to be associated with bone resortion, also are associated with superior semicircular canal dehiscence. Observational study. Study conducted in 3 tertiary Spanish hospitals. Nonselected consecutive patients of all ages. Thin-section multi-detector row computed tomographic scan of the temporal bones. The minimum thickness of the bone covering the roof of the superior semicircular canal (SSC) measured in each temporal bone. The outcome was studied both as a continuous and as a dichotomous variable: thin (<0.6 mm) and normal (≥ 0.6 mm). Five hundred eighty-two ears of 312 patients were included in the study. Fifty-five percent of the sample were women. Patient's age ranged from 2 to 88 years. A 40-year age difference between ears was associated with a decreased thickness of bone covering the SSC of 0.10 mm, which is 10% of the average thickness of such bone. The thickness of the bone overlying the SSC of subjects younger than 45 years was an average of 1.14 mm (SD, 0.52 mm), whereas that of the subjects older than 45 years was equal to 1.02 mm (SD, 0.45 mm; p = 0.006). The percentage of ears with thin bone coverage of SSC was 7.1% in subjects younger than 45 years and 13.8% in those older than 45 years (p = 0.013). Our data support the hypothesis that there is a slight osteopenia of the roof of the superior semicircular canal associated with aging, and this effect seems to be more pronounced in menopausal women.

  20. Optimizing the Vertebrate Vestibular Semicircular Canal: Could We Balance Any Better?

    NASA Astrophysics Data System (ADS)

    Squires, Todd M.

    2004-11-01

    The fluid-filled semicircular canals (SCCs) of the vestibular system are used by all vertebrates to sense angular rotation. Despite masses spanning seven decades, all mammalian SCCs are nearly the same size. We propose that the SCC represents a sensory organ that evolution has “optimally designed.” Four geometric parameters characterize the SCC, and “building materials” of given physical properties are assumed. Identifying physical and physiological constraints on SCC operation, we find the most sensitive SCC has dimensions consistent with available data. Since natural selection involves optimization, this approach may find broader use in understanding biological structures.

  1. [Isolated functional loss of the lateral semicircular canal in vestibular neuritis].

    PubMed

    Blödow, A; Helbig, R; Bloching, M; Walther, L E

    2013-01-01

    Today, modern tools in vestibular testing are feasible to provide information about functional status of all five peripheral vestibular receptors. Isolated or combined loss of crista and macula receptor function can be determined in the diagnostic process. We describe a seldom case of isolated functional loss of lateral semicircular canal receptor function in a 55-year-old patient. Whereas there was no ispilateral caloric response and video head impulse test revealed a catch-up saccade, air-conducted (AC) cervical and ocular vestibular-evoked myogenic potentials (cVEMP, oVEMP), subjective visual vertical and MRI were normal.

  2. Development of conductive hearing loss due to posterior semicircular canal dehiscence.

    PubMed

    Kubota, Marie; Kubo, Kazuhiko; Yasui, Tetsuro; Matsumoto, Nozomu; Komune, Shizuo

    2015-06-01

    We herein report a case of posterior semicircular canal dehiscence (SCD) syndrome who had been audiologically followed up for eight years. The patient originally had sensorineural hearing loss. The audiogram had gradually transformed to pure conductive hearing loss. The posterior SCD was identified in CT scan. The reported case showed the possibility to distinguish the mechanism at play underlying the typical conductive hearing loss in SCD patients by tracing the transition of the hearing loss pattern. This information is of much help to predict the hearing outcomes if surgical intervention were chosen for the treatment.

  3. Can the affected semicircular canal be predicted by the initial provoking position in benign paroxysmal positional vertigo?

    PubMed

    Shim, Dae Bo; Ko, Kyung Min; Kim, Ji Hong; Lee, Won-Sang; Song, Mee Hyun

    2013-09-01

    The study evaluated the relationship between the position that initially provoked vertigo and the affected semicircular canal (SCC) in patients with benign paroxysmal positional vertigo (BPPV), and aimed to predict the side affected by BPPV through history taking regarding the provoking position. Prospective study at a tertiary hospital. A total of 521 patients with BPPV involving the posterior or horizontal SCCs performed questionnaires at initial visit asking to choose the initial provoking position among the 10 positions corresponding to one of the three planes (roll, pitch, or yaw). After excluding 45 patients showing signs of simultaneous multiple canal or anterior canal involvement, the frequency of the provoking positions and the correlation between the side of the provoking position and the ear affected by BPPV were analyzed. There were 239 patients with posterior SCC BPPV (p-BPPV) and 237 patients with horizontal SCC BPPV (h-BPPV). The waking-up position was the most common provoking position in both types of BPPV. Statistically significant correlation was demonstrated between the side of the provoking position at the onset of vertigo and the affected side by BPPV (P < .01) in patients with p-BPPV as well as h-BPPV (geotropic type [Geo]), but not in patients with h-BPPV (apogeotropic type [Apo]). History taking regarding the side of provoking position at the onset of vertigo may help predict the side affected by BPPV in p-BPPV and h-BPPV (Geo). When h-BPPV (Apo) is suspected, further detailed examinations using additional localization methods should be performed. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

  4. Three-dimensional analysis of vestibular efferent neurons innervating semicircular canals of the gerbil

    NASA Technical Reports Server (NTRS)

    Purcell, I. M.; Perachio, A. A.

    1997-01-01

    areas of efferent terminal fields display a trend from smallest to largest for the central, peripheral, and planum types, respectively. Neurons that innervate the central zone of the crista do not extend into the peripheral or planum regions. Conversely, those neurons with terminal fields in the peripheral or planum regions do not innervate the central zone of the sensory neuroepithelium. The central zone of the crista is innervated preferentially by efferent neurons with cell bodies located in the ipsilateral group e. The peripheral and planum zones of the crista are innervated preferentially by efferent neurons with cell bodies located in the contralateral group e. A model incorporating our anatomic observations is presented describing an ipsilateral closed-loop feedback between ipsilateral efferent neurons and the periphery and an open-loop feed-forward innervation from contralateral efferent neurons. A possible role for the vestibular efferent neurons in the modulation of semicircular canal afferent response dynamics is proposed.

  5. Mondini-like malformation mimicking otosclerosis and superior semicircular canal dehiscence.

    PubMed

    Karlberg, M; Annertz, M; Magnusson, M

    2006-05-01

    In 2003, it was reported that superior semicircular canal dehiscence can mimic otosclerosis because of low-frequency bone conduction hearing gain and dissipation of air-conducted acoustic energy through the dehiscence. We report the case of a 17-year-old girl with left-sided combined hearing loss thought to be due to otosclerosis. Bone conduction thresholds were -10 dB at 250 and 500 Hz and she had a 40 dB air-bone gap at 250 Hz. When a tuning fork was placed at her ankle she heard it in her left ear. Acoustic reflexes and vestibular evoked myogenic potentials could be elicited bilaterally. Imaging of the temporal bones showed no otosclerosis, superior semicircular canal dehiscence or large vestibular aqueduct, but a left-sided, Mondini-like dysplasia of the cochlea with a modiolar deficiency could be seen. Mondini-like cochlear dysplasia should be added to the causes of inner-ear conductive hearing loss.

  6. Ultrastructural study of the semicircular canal cells of the frog Rana esculenta.

    PubMed

    Oudar, O; Ferrary, E; Feldmann, G

    1988-03-01

    The ultrastructure of the nonsensory cells (dark cells, transitional cells, and undifferentiated cells) of the frog semicircular canal was studied by using transmission electron microscopy in an attempt to correlate the structure with the functions of these epithelial cells. All the nonsensory cells were linked by tight junctions and desmosomes; this suggested that there is little paracellular ionic transport from perilymph to endolymph. In the dark cell epithelium, the apical intercellular spaces were dilated; in the basal part, numerous basolateral plasma membrane infoldings, containing mitochondria, delimited electron-lucent spaces. The undifferentiated cells and the transitional cells were devoid of any basal membrane infolding. Surrounding the semicircular canal, very flattened and interdigitated mesothelial cells constituted a thin multilayer tissue which limited the perilymphatic space. The morphological aspect of the dark cells suggests that they may play a role in the secretion and/or in the reabsorption of endolymph, which bathes the apical pole of these cells. The undifferentiated and transitional cells can play a role in the maintenance of the endolymphatic ionic composition because of their apical tight junctions and desmosomes.

  7. The Human Semicircular Canals Orientation Is More Similar to the Bonobos than to the Chimpanzees

    PubMed Central

    El Khoury, Marwan; Braga, José; Dumoncel, Jean; Nancy, Javotte; Esclassan, Remi; Vaysse, Frederic

    2014-01-01

    For some traits, the human genome is more closely related to either the bonobo or the chimpanzee genome than they are to each other. Therefore, it becomes crucial to understand whether and how morphostructural differences between humans, chimpanzees and bonobos reflect the well known phylogeny. Here we comparatively investigated intra and extra labyrinthine semicircular canals orientation using 260 computed tomography scans of extant humans (Homo sapiens), bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). Humans and bonobos proved more similarities between themselves than with chimpanzees. This finding did not fit with the well established chimpanzee – bonobo monophyly. One hypothesis was convergent evolution in which bonobos and humans produce independently similar phenotypes possibly in response to similar selective pressures that may be associated with postural adaptations. Another possibility was convergence following a “random walk” (Brownian motion) evolutionary model. A more parsimonious explanation was that the bonobo-human labyrinthine shared morphology more closely retained the ancestral condition with chimpanzees being subsequently derived. Finally, these results might be a consequence of genetic diversity and incomplete lineage sorting. The remarkable symmetry of the Semicircular Canals was the second major finding of this article with possible applications in taphonomy. It has the potential to investigate altered fossils, inferring the probability of post-mortem deformation which can lead to difficulties in understanding taxonomic variation, phylogenetic relationships, and functional morphology. PMID:24710502

  8. A superior semicircular canal dehiscence induced air-bone gap in chinchilla

    PubMed Central

    Songer, Jocelyn E.; Rosowski, John J.

    2010-01-01

    An SCD is a pathologic hole (or dehiscence) in the bone separating the superior semicircular canal from the cranial cavity that has been associated with a conductive hearing loss in patients with SCD syndrome. The conductive loss is defined by an audiometrically determined air-bone gap that results from the combination of a decrease in sensitivity to air-conducted sound and an increase in sensitivity to bone-conducted sound. Our goal is to demonstrate, through physiological measurements in an animal model, that mechanically altering the superior semicircular canal (SC) by introducing a hole (dehiscence) is sufficient to cause such an air-bone gap. We surgically introduced holes into the SC of chinchilla ears and evaluated auditory sensitivity (cochlear potential) in response to both air- and bone-conducted stimuli. The introduction of the SC hole led to a low-frequency (< 2000 Hz) decrease in sensitivity to air-conducted stimuli and a low-frequency (< 1000 Hz) increase in sensitivity to bone-conducted stimuli resulting in an air-bone gap. This result was consistent and reversible. The air-bone gaps in the animal results are qualitatively consistent with findings in patients with SCD syndrome. PMID:20638462

  9. Otic capsule dehiscence syndrome: Superior semicircular canal dehiscence syndrome with no radiographically visible dehiscence.

    PubMed

    Wackym, P Ashley; Wood, Scott J; Siker, David A; Carter, Dale M

    2015-08-01

    We conducted a prospective longitudinal study of two cohorts of patients who had superior semicircular canal dehiscence syndrome (SSCDS); one group had radiographically confirmed superior canal dehiscence (SCD), and the other exhibited no identified otic capsule dehiscence on imaging (no-iOCD). We compiled data obtained from prospective structured symptomatology interviews; diagnostic studies; three-dimensional, high-resolution, temporal bone computed tomography; and a retrospective case review from our tertiary care referral center. Eleven adults and 1 child with SSCDS were identified, surgically managed, and followed. Six of these patients-1 man and 5 women, aged 29 to 54 years at first surgery (mean: 41.8)-had radiologically confirmed SCD. The other 6 patients-1 man, 4 women, and 1 girl, aged 1 to 51 years (mean: 32.2)-had no-iOCD. The 6 adults with SCD underwent surgery via a middle cranial fossa approach with plugging procedures. The 5 adults and 1 child with no-iOCD underwent round window reinforcement (RWR) surgery. One SCD patient developed no-iOCD 1.5 years after SCD surgery, and she subsequently underwent RWR surgery. Our main outcome measures were patient symptomatology (with video documentation) and the results of diagnostic studies. Other than the character of migraine headaches, there was no difference in preoperative symptomatology between the two groups. Postoperatively, resolution of SSCDS symptoms ultimately occurred in all patients. Both the SCD and the no-iOCD groups experienced a highly significant improvement in postural control following treatment (Wilcoxon signed rank test, p < 0.001). We conclude that the term otic capsule dehiscence syndrome more accurately reflects the clinical syndrome of SSCDS since it includes both superior semicircular canal dehiscence and no-iOCD, as well as posterior and lateral semicircular canal dehiscence, all of which can manifest as SSCDS. We have also included links to videos in which 4 of the SSCDS patients

  10. Horizontal canal benign paroxysmal positional vertigo: diagnosis and treatment of 37 patients.

    PubMed

    Maranhão, Eliana Teixeira; Maranhão Filho, Péricles

    2015-06-01

    Benign paroxysmal positional vertigo (BPPV), the most frequent cause of vertigo is associated with high morbidity in the elderly population. The most common form is linked to debris in the posterior semicircular canal. However, there has been an increasing number of reported BPPV cases involving the horizontal canals. The purpose of this article is to highlight the clinical features, diagnosis, and treatment in 37 patients with horizontal canal BPPV; twenty-six with geotropic nystagmus, and eleven with the apogeotropic form. Treatment consisted of the Gufoni manoeuver in eighteen patients (48.6%), the barbecue 360° maneuver in twelve patients (32.4%), both manoeuvers in four patients (10.8%), both manoeuvers plus head shaking in one patient (2.7%), and the Gufoni maneuver plus head shaking in two patients. Cupulolithiasis patients were asked to sleep in a forced prolonged position. We obtained a complete resolution of vertigo and nystagmus in 30 patients (81.0%) on the initial visit.

  11. Neural processing of gravito-inertial cues in humans. I. Influence of the semicircular canals following post-rotatory tilt

    NASA Technical Reports Server (NTRS)

    Zupan, L. H.; Peterka, R. J.; Merfeld, D. M.; Peterson, B. W. (Principal Investigator)

    2000-01-01

    Sensory systems often provide ambiguous information. Integration of various sensory cues is required for the CNS to resolve sensory ambiguity and elicit appropriate responses. The vestibular system includes two types of sensors: the semicircular canals, which measure head rotation, and the otolith organs, which measure gravito-inertial force (GIF), the sum of gravitational force and inertial force due to linear acceleration. According to Einstein's equivalence principle, gravitational force is indistinguishable from inertial force due to linear acceleration. As a consequence, otolith measurements must be supplemented with other sensory information for the CNS to distinguish tilt from translation. The GIF resolution hypothesis states that the CNS estimates gravity and linear acceleration, so that the difference between estimates of gravity and linear acceleration matches the measured GIF. Both otolith and semicircular canal cues influence this estimation of gravity and linear acceleration. The GIF resolution hypothesis predicts that inaccurate estimates of both gravity and linear acceleration can occur due to central interactions of sensory cues. The existence of specific patterns of vestibuloocular reflexes (VOR) related to these inaccurate estimates can be used to test the GIF resolution hypothesis. To investigate this hypothesis, we measured eye movements during two different protocols. In one experiment, eight subjects were rotated at a constant velocity about an earth-vertical axis and then tilted 90 degrees in darkness to one of eight different evenly spaced final orientations, a so-called "dumping" protocol. Three speeds (200, 100, and 50 degrees /s) and two directions, clockwise (CW) and counterclockwise (CCW), of rotation were tested. In another experiment, four subjects were rotated at a constant velocity (200 degrees /s, CW and CCW) about an earth-horizontal axis and stopped in two different final orientations (nose-up and nose-down), a so

  12. Neural processing of gravito-inertial cues in humans. I. Influence of the semicircular canals following post-rotatory tilt

    NASA Technical Reports Server (NTRS)

    Zupan, L. H.; Peterka, R. J.; Merfeld, D. M.; Peterson, B. W. (Principal Investigator)

    2000-01-01

    Sensory systems often provide ambiguous information. Integration of various sensory cues is required for the CNS to resolve sensory ambiguity and elicit appropriate responses. The vestibular system includes two types of sensors: the semicircular canals, which measure head rotation, and the otolith organs, which measure gravito-inertial force (GIF), the sum of gravitational force and inertial force due to linear acceleration. According to Einstein's equivalence principle, gravitational force is indistinguishable from inertial force due to linear acceleration. As a consequence, otolith measurements must be supplemented with other sensory information for the CNS to distinguish tilt from translation. The GIF resolution hypothesis states that the CNS estimates gravity and linear acceleration, so that the difference between estimates of gravity and linear acceleration matches the measured GIF. Both otolith and semicircular canal cues influence this estimation of gravity and linear acceleration. The GIF resolution hypothesis predicts that inaccurate estimates of both gravity and linear acceleration can occur due to central interactions of sensory cues. The existence of specific patterns of vestibuloocular reflexes (VOR) related to these inaccurate estimates can be used to test the GIF resolution hypothesis. To investigate this hypothesis, we measured eye movements during two different protocols. In one experiment, eight subjects were rotated at a constant velocity about an earth-vertical axis and then tilted 90 degrees in darkness to one of eight different evenly spaced final orientations, a so-called "dumping" protocol. Three speeds (200, 100, and 50 degrees /s) and two directions, clockwise (CW) and counterclockwise (CCW), of rotation were tested. In another experiment, four subjects were rotated at a constant velocity (200 degrees /s, CW and CCW) about an earth-horizontal axis and stopped in two different final orientations (nose-up and nose-down), a so

  13. Mechanical versus CO2 laser occlusion of the posterior semicircular canal in humans.

    PubMed

    Antonelli, P J; Lundy, L B; Kartush, J M; Burgio, D L; Graham, M D

    1996-05-01

    The purpose of this study was to compare the effectiveness of mechanical and laser-assisted posterior semicircular canal occlusion (PCO) for the treatment of intractable benign paroxysmal positional vertigo (BPPV). Twelve consecutive patients with intractable BPPV underwent PCO by three surgeons, six with mechanical PCO and six with CO2 laser-assisted PCO. PCO eliminated positional vertigo in all patients treated with the laser and five of six patients treated without the laser. Dysequilibrium was present in all patients immediately postoperatively. This resolved in all patients treated with the CO2 laser but in only two of six patients treated without the laser (p = 0.03). Patients were hospitalized for dysequilibrium for an average of 5.2 and 2.8 days for the mechanical and laser-assisted groups, respectively. Preoperative and postoperative hearing was not significantly different between the groups. No clinically significant postoperative hearing loss was encountered in either group. These results suggest that PCO is an effective treatment for intractable BPPV. The incidence of dysequilibrium that persists following PCO may be reduced by using the CO2 laser to seal the membranous canal prior to occluding the bony canal.

  14. Apogeotropic Posterior Semicircular Canal Benign Paroxysmal Positional Vertigo: Some Clinical and Therapeutic Considerations

    PubMed Central

    Vannucchi, Paolo; Pecci, Rudi; Giannoni, Beatrice; Di Giustino, Fabio; Santimone, Rossana; Mengucci, Arianna

    2015-01-01

    We lately reported the cases of patients complaining positional vertigo whose nystagmic pattern was that of a peripheral torsional vertical positional down beating nystagmus originating from a lithiasis of the non-ampullary arm of the posterior semicircular canal (PSC). We considered this particular pathological picture the apogeotropic variant of PSC benign paroxysmal positional vertigo (BPPV). Since the description of the pilot cases we observed more than 150 patients showing the same clinical sign and course of symptoms. In this paper we describe, in detail, both nystagmus of apogeotropic PSC BPPV (A-PSC BPPV) and symptoms reported by patients trying to give a reasonable explanation for these clinical features. Moreover we developed two specific physical therapies directed to cure A-PSC BPPV. Preliminary results of these techniques are related. PMID:26557364

  15. Ocular versus cervical VEMPs in the diagnosis of superior semicircular canal dehiscence syndrome.

    PubMed

    Zuniga, M Geraldine; Janky, Kristen L; Nguyen, Kimanh D; Welgampola, Miriam S; Carey, John P

    2013-01-01

    To determine whether cervical vestibular evoked myogenic potential (cVEMP) thresholds or ocular VEMP (oVEMP) amplitudes are more sensitive and specific in the diagnosis of superior semicircular canal dehiscence syndrome (SCDS). Prospective case-control study. Tertiary referral center. Twenty-nine patients with SCDS (mean age 48 yr; range, 31-66 yr) and 25 age-matched controls (mean age 48 yr; range, 30-66 yr). cVEMP and oVEMP in response to air-conducted sound. All patients underwent surgery for repair of SCDS. cVEMP thresholds; oVEMP n10 and peak-to-peak amplitudes. cVEMP threshold results showed sensitivity and specificity ranging from 80% to 100% for the diagnosis of SCDS. In contrast, oVEMP amplitudes demonstrated sensitivity and specificity greater than 90%. oVEMP amplitudes are superior to cVEMP thresholds in the diagnosis of SCDS.

  16. Mechanisms and effects of transepithelial polarization in the isolated semicircular canal.

    PubMed

    Norris, C H; Miller, A J; Perin, P; Holt, J C; Guth, P S

    1998-09-01

    Previous studies have shown that galvanic stimulation of semicircular canal organs can modulate their afferent discharge. However, it has not been resolved whether this modulation derived from direct stimulation of hair cells, afferent nerve fibers, some combination of the two, or some as yet unknown path. This problem is addressed in the present study. Experiments were designed first to determine the gross current path necessary for the DC current to modulate afferent firing. These led to the conclusion that the current path had to flow between endolymph and perilymph across the neuroepithelium. Next, the various components in this established path were considered: the afferents, the hair cells, between the hair cells, or some combination of the three. These experiments led to the conclusion that the current pathway was across the hair cells causing transmitter release and thus affecting afferent activity.

  17. State-space receptive fields of semicircular canal afferent neurons in the bullfrog

    NASA Technical Reports Server (NTRS)

    Paulin, M. G.; Hoffman, L. F.

    2001-01-01

    Receptive fields are commonly used to describe spatial characteristics of sensory neuron responses. They can be extended to characterize temporal or dynamical aspects by mapping neural responses in dynamical state spaces. The state-space receptive field of a neuron is the probability distribution of the dynamical state of the stimulus-generating system conditioned upon the occurrence of a spike. We have computed state-space receptive fields for semicircular canal afferent neurons in the bullfrog (Rana catesbeiana). We recorded spike times during broad-band Gaussian noise rotational velocity stimuli, computed the frequency distribution of head states at spike times, and normalized these to obtain conditional pdfs for the state. These state-space receptive fields quantify what the brain can deduce about the dynamical state of the head when a single spike arrives from the periphery. c2001 Elsevier Science B.V. All rights reserved.

  18. Ecto-ATPase activity sites in vestibular tissues: an ultracytochemical study in frog semicircular canals.

    PubMed

    Gioglio, Luciana; Russo, Giancarlo; Polimeni, Mariarosa; Prigioni, Ivo

    2003-02-01

    The present study describes the localization and distribution of putative ecto-nucleoside-triphosphate-diphosphohydrolases in the frog semicircular canals. These enzymes provide the terminating mechanism of adenosine-5'-triphosphate (ATP) signalling. The localization of the ATP hydrolysis was mapped ultracytochemically using a one-step cerium citrate reaction. Electron-dense precipitates, indicating ecto-adenosine-triphosphatase (ecto-ATPase) activity, were found at the outer surface of plasma membranes of crista hair cells and supporting cells of the sensory epithelium, transitional cells and undifferentiated cells of the ampullar wall and dark cells constituting the secretory epithelium. Non-sensory cells of the ampulla usually exhibited reaction deposits at the level of both apical and basolateral membranes coming into contact with the endolymph and the perilymph respectively, while cells constituting the sensory epithelium showed evident differences in relation to their position. Hair cells and supporting cells of the peripheral regions exhibited clear reaction products both at the level of apical and basolateral membranes, while those of the isthmus region showed abundant reactivity only at the level of their apical membranes. Of particular interest was the observation that hair cell stereocilia exhibited an abundant ecto-ATPase activity, thus suggesting a possible colocalization of enzymatic sites with purinergic receptors and mechanotransduction channels. This strategic expression of ecto-ATPase sites could provide a rapid mechanism of ATP removal able to rapidly restore the sensitivity of transduction channels. In conclusion, the widespread distribution of ecto-ATPase sites at the level of sensory and non-sensory cells of the frog semicircular canals suggests that ATP may have a key role in controlling vestibular function.

  19. Risk of progressive hearing loss in untreated superior semicircular canal dehiscence.

    PubMed

    Patel, Neil S; Hunter, Jacob B; O'Connell, Brendan P; Bertrand, Natalie M; Wanna, George B; Carlson, Matthew L

    2017-05-01

    Patients with incidental or minimally symptomatic superior semicircular canal dehiscence (SSCD) are usually observed, without surgical repair. However, it remains unknown whether a labyrinthine fistula of the superior semicircular canal is associated with progressive conductive or sensorineural hearing loss over time. Retrospective review at two tertiary care academic referral centers. Adults analyzed were diagnosed with SSCD by high-resolution temporal bone computed tomography and vestibular evoked myogenic potential testing and observed with a minimum of two sequential audiograms. Patients with other potential causes of hearing impairment were excluded. A total of 40 ears in 30 adult patients (median age: 59 years; 63% female) were analyzed. Median audiometric follow-up was 23 months (range 1-136 months). None experienced a sudden hearing loss over the follow-up period. In patients with audiometric follow-up of at least 20 months (median 34 months), the median change in air-conduction pure tone average and air-bone gap was 0.9 decibels (dB) per year (interquartile range [IQR] 0-2.1) and 0.7 dB per year (IQR 0-2.0), respectively. Speech discrimination scores did not differ when comparing median initial (100%) and median final (98%) scores (P = 0.77). There was no statistically significant change in bone-conduction thresholds at 0.5, 1, 2, and 4 kHz over the period of observation. The risk of progressive hearing loss with observed SSCD is low during short- and intermediate-term follow-up. Further studies are necessary to determine whether late hearing loss occurs. Such information may be critical toward patient counseling regarding the need for and timing of surgery. 4. Laryngoscope, 127:1181-1186, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  20. Development of the otolith organs and semicircular canals in the Japanese red-bellied newt, Cynops pyrrhogaster

    NASA Technical Reports Server (NTRS)

    Wiederhold, M. L.; Yamashita, M.; Larsen, K. A.; Batten, J. S.; Koike, H.; Asashima, M.

    1995-01-01

    The sequence in which the otoliths and semicircular canals and their associated sensory epithelia appear and develop in the newt are described. Three-dimensional reconstruction of serial sections through the otic vesicle of newt embryos from stages 31 through 58 demonstrate the first appearance, relative position and growth of the otoliths. A single otolith is first seen in stage 33 embryos (approximately 9 days old); this splits into separate utricular and saccular otoliths at stage 40 (13 days). The lateral semicircular canal is the first to appear, at stage 41 (14 days). The anterior and posterior canals appear approximately one week later and the vestibular apparatus is essentially fully formed at stage 58 (approximately 5 weeks). The data reported here will serve as ground-based controls for fertilized newt eggs flown on the International Microgravity Laboratory-2 Space Shuttle flight, to investigate the influence of microgravity on the development of the gravity-sensing organs.

  1. Development of the otolith organs and semicircular canals in the Japanese red-bellied newt, Cynops pyrrhogaster

    NASA Technical Reports Server (NTRS)

    Wiederhold, M. L.; Yamashita, M.; Larsen, K. A.; Batten, J. S.; Koike, H.; Asashima, M.

    1995-01-01

    The sequence in which the otoliths and semicircular canals and their associated sensory epithelia appear and develop in the newt are described. Three-dimensional reconstruction of serial sections through the otic vesicle of newt embryos from stages 31 through 58 demonstrate the first appearance, relative position and growth of the otoliths. A single otolith is first seen in stage 33 embryos (approximately 9 days old); this splits into separate utricular and saccular otoliths at stage 40 (13 days). The lateral semicircular canal is the first to appear, at stage 41 (14 days). The anterior and posterior canals appear approximately one week later and the vestibular apparatus is essentially fully formed at stage 58 (approximately 5 weeks). The data reported here will serve as ground-based controls for fertilized newt eggs flown on the International Microgravity Laboratory-2 Space Shuttle flight, to investigate the influence of microgravity on the development of the gravity-sensing organs.

  2. Appearance of ocular vestibular evoked myogenic potential elicited by bone-conducted vibration in a patient with CHARGE syndrome with aplasia of all semicircular canals.

    PubMed

    Zhang, Qing; Kaga, Kimitaka; Takegoshi, Hideki; Matsuda, Takeshi

    2014-03-01

    We report VEMP results in a patient with aplasia of bilateral semicircular canals and a small vestibular cavity. The patient was a 27-year-old male. The computed tomograph showed absolutely no formation of his semicircular canals, together with hypoplasia of his vestibular cavity and cochlea in both ears. His oVEMP was recorded near the extraocular muscles on the left side when elicited by BCV in the Fz. The clinical profile of this patient suggested that oVEMP elicited by BCV recorded near the extraocular muscles originated from otolithic end organs, and not from semicircular canal afferents. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  3. The Effect of Superior Semicircular Canal Dehiscence on Intracochlear Sound Pressures

    NASA Astrophysics Data System (ADS)

    Nakajima, Hideko Heidi; Pisano, Dominic V.; Merchant, Saumil N.; Rosowski, John J.

    2011-11-01

    Semicircular canal dehiscence (SCD) is a pathological opening in the bony wall of the inner ear that can result in conductive hearing loss. The hearing loss is variable across patients, and the precise mechanism and source of variability is not fully understood. We use intracochlear sound pressure measurements in cadaveric preparations to study the effects of SCD size. Simultaneous measurement of basal intracochlear sound pressures in scala vestibuli (SV) and scala tympani (ST) quantifies the complex differential pressure across the cochlear partition, the stimulus that excites the partition. Sound-induced pressures in SV and ST, as well as stapes velocity and ear-canal pressure are measured simultaneously for various sizes of SCD followed by SCD patching. At low frequencies (<600 Hz) our results show that SCD decreases the pressure in both SV and ST, as well as differential pressure, and these effects become more pronounced as dehiscence size is increased. For frequencies above 1 kHz, the smallest pinpoint dehiscence can have the larger effect on the differential pressure in some ears. These effects due to SCD are reversible by patching the dehiscence.

  4. Expression and localization of ryanodine receptors in the frog semicircular canal.

    PubMed

    Perin, Paola; Botta, Laura; Tritto, Simona; Laforenza, Umberto

    2012-01-01

    Several experiments suggest an important role for store-released Ca²⁺ in hair cell organs: drugs targeting IP₃ and ryanodine (RyRs) receptors affect release from hair cells, and stores are thought to be involved in vesicle recycling at ribbon synapses. In this work we investigated the semicircular canal distribution of RyRs by immunofluorescence, using slice preparations of the sensory epithelium (to distinguish cell types) and flat mounts of the simpler nonsensory regions. RyRs were present in hair cells, mostly in supranuclear spots, but not in supporting cells; as regards nonsensory regions, they were also localized in dark cells and cells from the ductus. No labeling was found in nerve terminals, although nerve branches could be observed in proximity to hair cell RyR spots. The differential expression of RyR isoforms was studied by RT-PCR and immunoblotting, showing the presence of RyRα in both ampulla and canal arm and RyRβ in the ampulla only.

  5. Vestibular ablation and a semicircular canal prosthesis affect postural stability during head turns

    PubMed Central

    Thompson, Lara A.; Haburcakova, Csilla; Lewis, Richard F.

    2016-01-01

    In our study, we examined postural stability during head turns for two rhesus monkeys: one, single animal study contrasted normal and mild bilateral vestibular ablation and a second animal study contrasted severe bilateral vestibular ablation with and without prosthetic stimulation. The monkeys freely stood, unrestrained on a balance platform and made voluntary head turns between visual targets. To quantify each animals’ posture, motions of the head and trunk, as well as torque about the body’s center-of-mass, were measured. In the mildly ablated animal, we observed less foretrunk sway in comparison to the normal state. When the canal prosthesis provided electric stimulation to the severely ablated animal, it showed a decrease in trunk sway during head turns. Because the rhesus monkey with severe bilateral vestibular loss exhibited a decrease in trunk sway when receiving vestibular prosthetic stimulation, we propose that the prosthetic electrical stimulation partially restored head velocity information. Our results provide an indication that a semicircular canal prosthesis may be an effective way to improve postural stability in patients with severe peripheral vestibular dysfunction. PMID:27405997

  6. Responses of the frog primary vestibular afferents to direct vibration of the semicircular canal

    NASA Technical Reports Server (NTRS)

    Orlov, I. V.

    1980-01-01

    Responses of primary afferents (PA) of lateral semicircular canal to sinusoidal vibration of the canal wall within the range 0.05-200 Hz (mean amplitudes 5-15 microns) in immobilized frogs were studied. Dynamic characteristics (gain, phase) of relative linear velocity of the vibrator (micron X/s) were examined. At 0.2 Hz, the gain was 5.35 + or - 3.19 imp X/s /micron X/s (mean; S.D.; n=14) and linearly decreased if the frequency rose. Phase lag of relative velocity at 0.05 Hz was 49.8 deg + or - 16.5 deg (n=13) and at 1 Hz 97 deg + or - 9.4 deg (n=22). At 100 Hz phase lag was about 240 deg. Three groups of PA are described: wide range PA reacting in the range from 0.05 up to 60-180 Hz; high frequency PA responding in the range from 20-40 up to 100-150 Hz; and low frequency PA responding in the range from 0.05 up to 2-20 Hz.

  7. Vestibular ablation and a semicircular canal prosthesis affect postural stability during head turns.

    PubMed

    Thompson, Lara A; Haburcakova, Csilla; Lewis, Richard F

    2016-11-01

    In our study, we examined postural stability during head turns for two rhesus monkeys: one animal study contrasted normal and mild bilateral vestibular ablation and a second animal study contrasted severe bilateral vestibular ablation with and without prosthetic stimulation. The monkeys freely stood, unrestrained on a balance platform and made voluntary head turns between visual targets. To quantify each animals' posture, motions of the head and trunk, as well as torque about the body's center of mass, were measured. In the mildly ablated animal, we observed less foretrunk sway in comparison with the normal state. When the canal prosthesis provided electric stimulation to the severely ablated animal, it showed a decrease in trunk sway during head turns. Because the rhesus monkey with severe bilateral vestibular loss exhibited a decrease in trunk sway when receiving vestibular prosthetic stimulation, we propose that the prosthetic electrical stimulation partially restored head velocity information. Our results provide an indication that a semicircular canal prosthesis may be an effective way to improve postural stability in patients with severe peripheral vestibular dysfunction.

  8. Adenylate cyclase and carbonic anhydrase in the semicircular canal epithelium of the frog Rana esculenta. An ultrastructural cytochemical localization.

    PubMed

    Oudar, O; Ferrary, E; Feldmann, G

    1990-12-01

    Because the secretion of endolymph has been localized in the ampullar part of the frog semicircular canal, we attempted to determine by cytochemical methods the ultrastructural localization of two enzymes that are assumed to play a role in endolymph secretion: carbonic anhydrase and adenylate cyclase. Functionally, the epithelium of the frog semicircular canal can be schematically divided into three areas: sensory (crista ampullaris), secretory (dark cells), and non-sensory and nonsecretory (transitional and undifferentiated cells) areas. Carbonic anhydrase activity was widely distributed in dark cells. Dark cell labeling disappeared in the presence of acetazolamide. The other cells of the canal did not show any carbonic anhydrase labeling except for the supporting cells of the sensory cells. Adenylate cyclase activity was found on the basolateral and apical membranes of dark cells, and on the apical membrane of sensory cells; weak labeling was also observed in the other epithelial cells. In the apical membrane of the dark cells, adenylate cyclase labeling was dependent on the presence of vasotocin, the frog antidiuretic hormone. The dark cells of the frog semicircular canal thus possess the enzyme equipment needed for the secretion of endolymph and its possible hormonal regulation.

  9. IP3 receptor in the hair cells of frog semicircular canal and its possible functional role.

    PubMed

    Rossi, Maria Lisa; Prigioni, Ivo; Gioglio, Luciana; Rubbini, Gemma; Russo, Giancarlo; Martini, Marta; Farinelli, Federica; Rispoli, Giorgio; Fesce, Riccardo

    2006-04-01

    The presence and functional role of inositol trisphosphate receptors (IP3R) was investigated by electrophysiology and immunohistochemistry in hair cells from the frog semicircular canal. Intracellular recordings were performed from single fibres of the posterior canal in the isolated, intact frog labyrinth, at rest and during rotation, in the presence of IP3 receptor inhibitors and drugs known to produce Ca2+ release from the internal stores or to increase IP3 production. Hair cell immunolabelling for IP3 receptor was performed by standard procedures. The drug 2-aminoethoxydiphenyl borate (2APB), an IP3 receptor inhibitor, produced a marked decrease of mEPSP and spike frequency at low concentration (0.1 mm), without affecting mEPSP size or time course. At high concentration (1 mm), 2APB is reported to block the sarcoplasmic-endoplasmic reticulum Ca2+-ATPase (SERCA pump) and increase [Ca2+]i; at the labyrinthine cytoneural junction, it greatly enhanced the resting and mechanically evoked sensory discharge frequency. The selective agonist of group I metabotropic glutamate receptors (RS)-3,5-dihydroxyphenylglycine (DHPG, 0.6 mm), produced a transient increase in resting mEPSP and spike frequency at the cytoneural junction, with no effects on mEPSP shape or amplitude. Pretreatment with cyclopiazonic acid (CPA, 0.1 mm), a SERCA pump inhibitor, prevented the facilitatory effect of both 2APB and DHPG, suggesting a link between Ca2+ release from intracellular stores and quantal emission. Consistently, diffuse immunoreactivity for IP3 receptors was observed in posterior canal hair cells. Our results indicate the presence and a possibly relevant functional role of IP3-sensitive stores in controlling [Ca2+]i and modulating the vestibular discharge.

  10. [Action of vestibular receptors pn the spontaneous afferent activity of an ipsilateral semicircular canal in the frog].

    PubMed

    Caston, J; Gribenski, A

    1976-01-01

    In the frog, the influence of both the part of the efferent system which depends on ipsilateral vestibular inputs and the receptor-receptor fibre system on the afferent activity of semicircular canals is either null or facilitatory. The receptor-receptor fibre system being inhibitory, it seems that the part of the efferent vestibular activity which depends on ipsilateral vestibular inputs is facilitatory, which agrees with previous results.

  11. The Density Difference of Cupula and Endolymph Changes the Mechanics of Semicircular Canals

    NASA Astrophysics Data System (ADS)

    Kondrachuk, Alexander V.; Boyle, Richard D.

    2011-11-01

    A precise balance of cupula and endolymph densities is key to the proper sensing of angular acceleration by the semicircular canals (SC). Estimates show that a density difference of cupula and endolymph (DD) as small as 10 - 4 g/cm3 is sufficient to make the SC sensitive to gravity and centrifugal forces provided they are comparable with gravity. As a result this might cause vestibular disorders. There are conditions under which the DD may even exceed this value. One of them is a change of intra-labyrinth pressure (IP) that may take place during a spaceflight. Here, the effect of DD on SC dynamics is considered using a simplified one-dimensional toroidal mathematical model of a canal for rotation with constant or harmonically oscillating angular velocities. The DD results in: dependence of cupula dynamics on orientation of both the gravity vector relative to the SC plane and the axis of rotation, as well as on the distance between the axis of rotation and the center of SC; shift of the cupula to a new position of equilibrium that depends on both the gravity vector and the parameters of head rotation; and onset of cupula oscillations with multiple frequencies under harmonic stimulation. The DD effect may be important under conditions of artificial gravity where the directions of centrifugal forces, the values of which are comparable with Earth's gravity, the orientations of the axis of rotation of a space station, and the axes of the SCs change during movements of the individuals and their habitat.

  12. Computerized Assessment of Superior Semicircular Canal Dehiscence Size using Advanced Morphological Imaging Operators.

    PubMed

    Beckett, Joel S; Lagman, Carlito; Chung, Lawrance K; Bui, Timothy T; Lee, Seung J; Voth, Brittany L; Gaonkar, Bilwaj; Gopen, Quinton; Yang, Isaac

    2017-04-01

    Superior semicircular canal dehiscence (SSCD) describes a pathological aperture at the level of the arcuate eminence. Techniques for quantifying defect size are described with most studies using two-dimensional lengths that underestimate the pathology. The objective of this study is to describe a novel method of measurement that combines manual segmentation of high-resolution computed tomography (HRCT) images of the temporal bone and a morphological skeletonization transform to calculate dehiscence volume. Images were imported into a freely available image segmentation tool: ITK-SNAP (version 3.4.0; available at: http://www.itksnap.org/) software. Coronal and sagittal planes were used to outline the dehiscence in all slices demonstrating the defect using the paintbrush tool. A morphological skeletonization transform derived a single-pixel thick representation of the original delineation. This "sheet" of voxels overlaid the dehiscence. Volume was calculated by counting the number of nonzero image voxels within this "sheet" and multiplying this number by the volume (mm(3)) of each voxel. A total of 70 cases of SSCD were identified. Overall, mean volume was 0.88 mm(3) (standard deviation: 0.57, range: 0.11-2.27). We present a novel technique for measuring SSCD, which we believe provides a more accurate representation of the pathology, and has the potential to standardize measurement of SSCD.

  13. Convergence of limb, visceral, and vertical semicircular canal or otolith inputs onto vestibular nucleus neurons

    NASA Technical Reports Server (NTRS)

    Jian, B. J.; Shintani, T.; Emanuel, B. A.; Yates, B. J.

    2002-01-01

    The major goal of this study was to determine the patterns of convergence of non-labyrinthine inputs from the limbs and viscera onto vestibular nucleus neurons receiving signals from vertical semicircular canals or otolith organs. A secondary aim was to ascertain whether the effects of non-labyrinthine inputs on the activity of vestibular nucleus neurons is affected by bilateral peripheral vestibular lesions. The majority (72%) of vestibular nucleus neurons in labyrinth-intact animals whose firing was modulated by vertical rotations responded to electrical stimulation of limb and/or visceral nerves. The activity of even more vestibular nucleus neurons (93%) was affected by limb or visceral nerve stimulation in chronically labyrinthectomized preparations. Some neurons received non-labyrinthine inputs from a variety of peripheral sources, including antagonist muscles acting at the same joint, whereas others received inputs from more limited sources. There was no apparent relationship between the spatial and dynamic properties of a neuron's responses to tilts in vertical planes and the non-labyrinthine inputs that it received. These data suggest that non-labyrinthine inputs elicited during movement will modulate the processing of information by the central vestibular system, and may contribute to the recovery of spontaneous activity of vestibular nucleus neurons following peripheral vestibular lesions. Furthermore, some vestibular nucleus neurons with non-labyrinthine inputs may be activated only during particular behaviors that elicit a specific combination of limb and visceral inputs.

  14. Electrical filtering in gerbil isolated type I semicircular canal hair cells

    NASA Technical Reports Server (NTRS)

    Rennie, K. J.; Ricci, A. J.; Correia, M. J.

    1996-01-01

    1. Membrane potential responses of dissociated gerbil type I semicircular canal hair cells to current injections in whole cell current-clamp have been measured. The input resistance of type I cells was 21.4 +/- 14.3 (SD) M omega, (n = 25). Around the zero-current potential (Vz = -66.6 +/- 9.3 mV, n = 25), pulsed current injections (from approximately -200 to 750 pA) produced only small-amplitude, pulse-like changes in membrane potential. 2. Injecting constant current to hyperpolarize the membrane to around -100 mV resulted in a approximately 10-fold increase in membrane resistance. Current pulses superimposed on this constant hyperpolarization produced larger and more complex membrane potential changes. Depolarizing currents > or = 200 pA caused a rapid transient peak voltage before a plateau. 3. Membrane voltage was able to faithfully follow sine-wave current injections around Vz over the range 1-1,000 Hz with < 25% attenuation at 1 kHz. A previously described K conductance, IKI, which is active at Vz, produces the low input resistance and frequency response. This was confirmed by pharmacologically blocking IKI. This conductance, present in type I cells but not type II hair cells, would appear to confer on type I cells a lower gain, but a much broader bandwidth at Vz, than seen in type II cells.

  15. A Mathematical Model of Human Semicircular Canal Geometry: A New Basis for Interpreting Vestibular Physiology

    PubMed Central

    Curthoys, Ian S.; Todd, Michael J.; Magnussen, John S.; Taubman, David S.; Aw, Swee T.; Halmagyi, G. Michael

    2009-01-01

    We report a precise, simple, and accessible method of mathematically measuring and modeling the three-dimensional (3D) geometry of semicircular canals (SCCs) in living humans. Knowledge of this geometry helps understand the development and physiology of SCC stimulation. We developed a framework of robust techniques that automatically and accurately reconstruct SCC geometry from computed tomography (CT) images and are directly validated using micro-CT as ground truth. This framework measures the 3D centroid paths of the bony SCCs allowing direct comparison and analysis between ears within and between subjects. An average set of SCC morphology is calculated from 34 human ears, within which other geometrical attributes such as nonplanarity, radius of curvature, and inter-SCC angle are examined, with a focus on physiological implications. These measurements have also been used to critically evaluate plane fitting techniques that reconcile many of the discrepancies in current SCC plane studies. Finally, we mathematically model SCC geometry using Fourier series equations. This work has the potential to reinterpret physiology and pathophysiology in terms of real individual 3D morphology. Electronic supplementary material The online version of this article (doi:10.1007/s10162-009-0195-6) contains supplementary material, which is available to authorized users. PMID:19949828

  16. Electrical filtering in gerbil isolated type I semicircular canal hair cells

    NASA Technical Reports Server (NTRS)

    Rennie, K. J.; Ricci, A. J.; Correia, M. J.

    1996-01-01

    1. Membrane potential responses of dissociated gerbil type I semicircular canal hair cells to current injections in whole cell current-clamp have been measured. The input resistance of type I cells was 21.4 +/- 14.3 (SD) M omega, (n = 25). Around the zero-current potential (Vz = -66.6 +/- 9.3 mV, n = 25), pulsed current injections (from approximately -200 to 750 pA) produced only small-amplitude, pulse-like changes in membrane potential. 2. Injecting constant current to hyperpolarize the membrane to around -100 mV resulted in a approximately 10-fold increase in membrane resistance. Current pulses superimposed on this constant hyperpolarization produced larger and more complex membrane potential changes. Depolarizing currents > or = 200 pA caused a rapid transient peak voltage before a plateau. 3. Membrane voltage was able to faithfully follow sine-wave current injections around Vz over the range 1-1,000 Hz with < 25% attenuation at 1 kHz. A previously described K conductance, IKI, which is active at Vz, produces the low input resistance and frequency response. This was confirmed by pharmacologically blocking IKI. This conductance, present in type I cells but not type II hair cells, would appear to confer on type I cells a lower gain, but a much broader bandwidth at Vz, than seen in type II cells.

  17. An indicator of probable semicircular canal dehiscence: ocular vestibular evoked myogenic potentials to high frequencies.

    PubMed

    Manzari, Leonardo; Burgess, Ann M; McGarvie, Leigh A; Curthoys, Ian S

    2013-07-01

    The n10 component of the ocular vestibular evoked myogenic potential (oVEMP) to sound and vibration stimuli is a crossed response that has enhanced amplitude and decreased threshold in patients with CT-verified superior semicircular canal dehiscence (SSCD). However, demonstrating enhanced VEMP amplitude and reduced VEMP thresholds requires multiple trials and can be very time consuming and tiring for patients, so a specific indicator of probable SCD that is fast and not tiring would be preferred. Here we report a 1-trial indicator: that the oVEMP n10 in response to a very high frequency stimulus (4000 Hz), either air-conducted sound (ACS) or bone conducted vibration (BCV), is such a fast indicator of probable SCD. In 22 healthy subjects, oVEMP n10 at 4000 Hz was not detectable; however, in all 22 CT-verified SSCD patients tested, oVEMP n10 responses were clearly present to 4000 Hz to either ACS or BCV stimuli.

  18. Ocular vs. Cervical VEMPs in the Diagnosis of Superior Semicircular Canal Dehiscence Syndrome

    PubMed Central

    Zuniga, M. Geraldine; Janky, Kristen L.; Nguyen, Kimanh D.; Welgampola, Miriam S.; Carey, John P.

    2012-01-01

    Objectives To determine whether cervical vestibular evoked myogenic potential (cVEMP) thresholds or ocular VEMP amplitudes are more sensitive and specific in the diagnosis of superior semicircular canal dehiscence syndrome (SCDS). Study design Prospective case-control study Setting Tertiary referral center Subjects and Methods 29 patients with SCDS (mean age 48y; range 31–66y) and 25 age-matched controls (mean age 48y; range 30–66y). Intervention(s) cVEMP and oVEMP in response to air-conducted sound (ACS). All patients underwent surgery for repair of SCDS. Main outcome measure(s) cVEMP thresholds; oVEMP n10 and peak-to-peak amplitudes. Results cVEMP threshold results showed sensitivity and specificity ranging from 80–100% for the diagnosis of SCDS. In contrast, oVEMP amplitudes demonstrated sensitivity and specificity >90%. Conclusions oVEMP amplitudes are superior to cVEMP thresholds in the diagnosis of SCDS. PMID:23183641

  19. The association between semicircular canal dehiscence and Chiari type I malformation.

    PubMed

    Kuhn, Jeffery J; Clenney, Timothy

    2010-10-01

    To investigate the association between semicircular canal dehiscence (SCD) and Chiari type I malformation (CM-I). Retrospective case series. Military tertiary referral center. Adult patients with SCD. Review of records of patients diagnosed as having SCD for the radiologic diagnosis of CM-I and presenting symptoms. The prevalence of CM-I among patients with SCD and the presenting symptoms of patients with SCD with and without a coexistent CM-I. Of 32 patients diagnosed as having SCD, 30 underwent magnetic resonance imaging of the brain. Seven patients (23%; 95% confidence interval [CI], 12%-41%) were found to have a CM-I. Chiari type I malformation was associated with superior SCD in 3 of 26 patients (12%; 95% CI, 3%-30%). Of 10 patients with bilateral superior SCD, 2 (20%; 95% CI, 5%-52%) had a CM-I. Five of 6 patients (83%; 95% CI, 42%-99%) had a CM-I with unilateral or bilateral posterior SCD. Twenty-nine records were reviewed for presenting symptoms, and no significant difference was observed between patients with SCD alone and those with an associated CM-I (P = .09-.64). Among patients with SCD, the prevalence of CM-I is elevated. This association is especially marked in patients with posterior SCD. This finding suggests a relationship between CM-I and SCD, particularly with posterior SCD.

  20. Convergence of limb, visceral, and vertical semicircular canal or otolith inputs onto vestibular nucleus neurons

    NASA Technical Reports Server (NTRS)

    Jian, B. J.; Shintani, T.; Emanuel, B. A.; Yates, B. J.

    2002-01-01

    The major goal of this study was to determine the patterns of convergence of non-labyrinthine inputs from the limbs and viscera onto vestibular nucleus neurons receiving signals from vertical semicircular canals or otolith organs. A secondary aim was to ascertain whether the effects of non-labyrinthine inputs on the activity of vestibular nucleus neurons is affected by bilateral peripheral vestibular lesions. The majority (72%) of vestibular nucleus neurons in labyrinth-intact animals whose firing was modulated by vertical rotations responded to electrical stimulation of limb and/or visceral nerves. The activity of even more vestibular nucleus neurons (93%) was affected by limb or visceral nerve stimulation in chronically labyrinthectomized preparations. Some neurons received non-labyrinthine inputs from a variety of peripheral sources, including antagonist muscles acting at the same joint, whereas others received inputs from more limited sources. There was no apparent relationship between the spatial and dynamic properties of a neuron's responses to tilts in vertical planes and the non-labyrinthine inputs that it received. These data suggest that non-labyrinthine inputs elicited during movement will modulate the processing of information by the central vestibular system, and may contribute to the recovery of spontaneous activity of vestibular nucleus neurons following peripheral vestibular lesions. Furthermore, some vestibular nucleus neurons with non-labyrinthine inputs may be activated only during particular behaviors that elicit a specific combination of limb and visceral inputs.

  1. AM-111 prevents hearing loss from semicircular canal injury in otitis media.

    PubMed

    Grindal, Tyler C; Sampson, Edith M; Antonelli, Patrick J

    2010-01-01

    Iatrogenic semicircular canal (SC) transection during mastoidectomy for chronic otitis media often leads to profound hearing loss. AM-111, an apoptosis inhibitor, has been shown to mitigate hearing loss resulting from a variety of inner ear injuries. The goal of this study was to determine if round window application of AM-111 following SC transection in the presence of Pseudomonas aeruginosa otitis media (PA-OM) may reduce the associated hearing loss. Prospective, randomized, controlled study in an animal model. PA-OM was induced bilaterally in 34 guinea pigs. After 3 days, both bullae were opened and the lateral SC of one ear was transected. AM-111 or vehicle was applied topically to the round window of the ear that had undergone SC transection. Hearing was assessed with auditory brainstem responses. The mean change in hearing thresholds was significantly less in transected ears treated with AM-111 than those receiving vehicle alone when testing with clicks (22.1 dB vs. 35.0 dB; P = .019) and at 4kHz (11.3 dB vs. 40.0 dB; P = .021). A similar trend was shown with 16 kHz tone pips (27.7 dB vs. 41.1 dB; P = .119). AM-111 prevents hearing loss from SC transection in the guinea pig model of PA-OM.

  2. Implantation of the Semicircular Canals with Preservation of Hearing and Rotational Sensitivity: a vestibular neurostimulator suitable for clinical research

    PubMed Central

    Rubinstein, Jay T; Bierer, Steven; Kaneko, Chris; Ling, Leo; Nie, Kaibao; Oxford, Trey; Newlands, Shawn; Santos, Felipe; Risi, Frank; Abbas, Paul J; Phillips, James O

    2012-01-01

    Hypothesis It is possible to implant a stimulating electrode array in the semicircular canals without damaging rotational sensitivity or hearing. The electrodes will evoke robust and precisely controlled eye-movements Background A number of groups are attempting to develop a neural prosthesis to ameliorate abnormal vestibular function. Animal studies demonstrate that electrodes near the canal ampullae can produce electrically-evoked eye movements. The target condition of these studies is typically bilateral vestibular hypofunction. Such a device could potentially be more widely useful clinically, and would have a simpler roadmap to regulatory approval if it produced minimal or no damage to the native vestibular and auditory systems. Methods An electrode array was designed for insertion into the bony semicircular canal adjacent to the membranous canal. It was designed to be sufficiently narrow so as to not compress the membranous canal. The arrays were manufactured by Cochlear Ltd and linked to a Nucleus Freedom receiver/stimulator. Seven behaviorally-trained rhesus macaques had arrays placed in two semicircular canals using a transmastoid approach and “soft-surgical” procedures borrowed from Hybrid cochlear implant surgery. Postoperative vestibulo-ocular reflex was measured in a rotary chair. Click-evoked auditory brainstem responses were also measured in the seven animals using the contralateral ear as a control. Results All animals had minimal postoperative vestibular signs and were eating within hours of surgery. Six out of six animals tested had normal postoperative sinusoidal gain. Six out of seven animals had symmetric postoperative velocity-step responses toward and away from the implanted ear. The one animal with significantly asymmetric velocity-step responses also had a significant sensorineural hearing loss. One control animal which underwent canal-plugging had substantial loss of the velocity-step response toward the canal-plugged ear. In five

  3. Implantation of the semicircular canals with preservation of hearing and rotational sensitivity: a vestibular neurostimulator suitable for clinical research.

    PubMed

    Rubinstein, Jay T; Bierer, Steven; Kaneko, Chris; Ling, Leo; Nie, Kaibao; Oxford, Trey; Newlands, Shawn; Santos, Felipe; Risi, Frank; Abbas, Paul J; Phillips, James O

    2012-07-01

    It is possible to implant a stimulating electrode array in the semicircular canals without damaging rotational sensitivity or hearing. The electrodes will evoke robust and precisely controlled eye movements. A number of groups are attempting to develop a neural prosthesis to ameliorate abnormal vestibular function. Animal studies demonstrate that electrodes near the canal ampullae can produce electrically evoked eye movements. The target condition of these studies is typically bilateral vestibular hypofunction. Such a device could potentially be more widely useful clinically and would have a simpler roadmap to regulatory approval if it produced minimal or no damage to the native vestibular and auditory systems. An electrode array was designed for insertion into the bony semicircular canal adjacent to the membranous canal. It was designed to be sufficiently narrow so as to not compress the membranous canal. The arrays were manufactured by Cochlear, Ltd., and linked to a Nucleus Freedom receiver/stimulator. Seven behaviorally trained rhesus macaques had arrays placed in 2 semicircular canals using a transmastoid approach and "soft surgical" procedures borrowed from Hybrid cochlear implant surgery. Postoperative vestibulo-ocular reflex was measured in a rotary chair. Click-evoked auditory brainstem responses were also measured in the 7 animals using the contralateral ear as a control. All animals had minimal postoperative vestibular signs and were eating within hours of surgery. Of 6 animals tested, all had normal postoperative sinusoidal gain. Of 7 animals, 6 had symmetric postoperative velocity step responses toward and away from the implanted ear. The 1 animal with significantly asymmetric velocity step responses also had a significant sensorineural hearing loss. One control animal that underwent canal plugging had substantial loss of the velocity step response toward the canal-plugged ear. In 5 animals, intraoperative electrically evoked vestibular compound action

  4. Interaction of semicircular canal stimulation with carotid baroreceptor reflex control of heart rate

    NASA Technical Reports Server (NTRS)

    Convertino, V. A.

    1998-01-01

    The carotid-cardiac baroreflex contributes to the prediction of orthostatic tolerance; experimental attenuation of the reflex response leads to orthostatic hypotension in humans and animals. Anecdotal observations indicate that rotational head movements about the vertical axis of the body can also induce orthostatic bradycardia and hypotension through increased parasympathetic activity. We therefore measured the chronotropic response to carotid baroreceptor stimulation in 12 men during varying conditions of vestibulo-oculomotor stimulation to test the hypothesis that stimulation of the semicircular canals associated with head movements in the yaw plane inhibits cardioacceleration through a vagally mediated baroreflex. Carotid-cardiac baroreflex response was assessed by plotting R-R intervals (ms) at each of 8 neck pressure steps with their respective carotid distending pressures (mmHg). Calculated baroreflex gain (maximal slope of the stimulus-response relationship) was measured under 4 experimental conditions: 1) sinusoidal whole-body yaw rotation of the subject in the dark without visual fixation (combined vestibular-oculomotor stimulation); 2) yaw oscillation of the subject while tracking a small head-fixed light moving with the subject (vestibular stimulation without eye movements); 3) subject stationary while fixating on a small light oscillating in yaw at the same frequency, peak acceleration, and velocity as the chair (eye movements without vestibular stimulation); and 4) subject stationary in the dark (no eye or head motion). Head motion alone and with eye movement reduced baseline baroreflex responsiveness to the same stimulus by 30%. Inhibition of cardioacceleration during rotational head movements may have significant impact on functional performance in aerospace environments, particularly in high-performance aircraft pilots during high angular acceleration in aerial combat maneuvers or in astronauts upon return from spaceflight who already have

  5. Cervical and Ocular VEMP Testing in Diagnosing Superior Semicircular Canal Dehiscence.

    PubMed

    Hunter, Jacob B; Patel, Neil S; O'Connell, Brendan P; Carlson, Matthew L; Shepard, Neil T; McCaslin, Devin L; Wanna, George B

    2017-05-01

    Objective To determine the sensitivity and specificity of ocular and cervical vestibular evoked myogenic potentials (VEMPs) in the diagnosis of superior semicircular canal dehiscence (SCD) and to describe the VEMP response characteristics that are most sensitive to SCD and compare the findings to previous reports. Study Design Case series with chart review. Setting Two tertiary neurotologic referral centers. Subjects and Methods Cervical and ocular VEMP peak-to-peak amplitudes and thresholds from 39 adult patients older than 18 years with surgically confirmed SCD were compared with 84 age-matched controls. Results Using receiver operating characteristic (ROC) curves, cervical VEMP (cVEMP) amplitudes, cVEMP thresholds, and ocular VEMP (oVEMP) amplitudes had areas under the curve of 0.731, 0.912, and 0.856, respectively, all of which were statistically significant ( P < .0001). For cVEMP thresholds, at the clinical equivalent ≤85-dB normalized hearing level (nHL) threshold, the sensitivity and specificity were 97.3% and 31.3%, respectively. At the ≤70-dB nHL threshold, the sensitivity and specificity were 73.0% and 94.0%, respectively. For oVEMP amplitudes >12.0 µV, the sensitivity and specificity were 78.6% and 81.7%, respectively. Conclusion Data from this multicenter study suggest that both cVEMP thresholds and oVEMP amplitudes remain good diagnostic tests for identifying SCD, with each test dependent on a number of factors. The sensitivity and specificity of these individual tests may vary slightly between centers depending on testing parameters used.

  6. Interaction of semicircular canal stimulation with carotid baroreceptor reflex control of heart rate

    NASA Technical Reports Server (NTRS)

    Convertino, V. A.

    1998-01-01

    The carotid-cardiac baroreflex contributes to the prediction of orthostatic tolerance; experimental attenuation of the reflex response leads to orthostatic hypotension in humans and animals. Anecdotal observations indicate that rotational head movements about the vertical axis of the body can also induce orthostatic bradycardia and hypotension through increased parasympathetic activity. We therefore measured the chronotropic response to carotid baroreceptor stimulation in 12 men during varying conditions of vestibulo-oculomotor stimulation to test the hypothesis that stimulation of the semicircular canals associated with head movements in the yaw plane inhibits cardioacceleration through a vagally mediated baroreflex. Carotid-cardiac baroreflex response was assessed by plotting R-R intervals (ms) at each of 8 neck pressure steps with their respective carotid distending pressures (mmHg). Calculated baroreflex gain (maximal slope of the stimulus-response relationship) was measured under 4 experimental conditions: 1) sinusoidal whole-body yaw rotation of the subject in the dark without visual fixation (combined vestibular-oculomotor stimulation); 2) yaw oscillation of the subject while tracking a small head-fixed light moving with the subject (vestibular stimulation without eye movements); 3) subject stationary while fixating on a small light oscillating in yaw at the same frequency, peak acceleration, and velocity as the chair (eye movements without vestibular stimulation); and 4) subject stationary in the dark (no eye or head motion). Head motion alone and with eye movement reduced baseline baroreflex responsiveness to the same stimulus by 30%. Inhibition of cardioacceleration during rotational head movements may have significant impact on functional performance in aerospace environments, particularly in high-performance aircraft pilots during high angular acceleration in aerial combat maneuvers or in astronauts upon return from spaceflight who already have

  7. Lateral Skull Base Attenuation in Superior Semicircular Canal Dehiscence and Spontaneous Cerebrospinal Fluid Otorrhea.

    PubMed

    Rizk, Habib G; Hatch, Jonathan L; Stevens, Shawn M; Lambert, Paul R; Meyer, Ted A

    2016-10-01

    (1) To quantitatively assess the lateral skull base thickness in patients with superior semicircular canal dehiscense (SSCD) using a standardized and validated radiographic measure and to compare it with that of a population with spontaneous cerebrospinal fluid otorrhea (CSFO). (2) To analyze demographic and clinical factors associated with skull base thickness in the SSCD group. Case series with chart review. Tertiary neurotologic referral center. Based on computed tomography imaging of the tegmen, mean skull base thickness was calculated for 16 patients with radiographic and clinical SSCD. Similar measures were performed in 4 comparison groups consisting of adults with spontaneous CSFO (n = 33), as well as 3 control groups recruited from our adult cochlear implant database: 30 obese controls (body mass index [BMI] >30 kg/m(2)), 11 overweight controls (BMI, 25-30 kg/m(2)), and 20 normal weight controls (BMI <25 kg/m(2)). The SSCD group had a significantly lower mean BMI (28.6 kg/m(2)) than the spontaneous CSFO group (37.7 kg/m(2); P = .0007). The mean skull base thickness of SSCD patients was 17% thinner than that of the CSFO group, 31% thinner vs obese controls, 49% thinner vs overweight controls, and 45% thinner vs normal weight controls. These differences were all statistically significant (P < .05). Patients with SSCD have a marked thinning of the lateral skull base, more so than patients with spontaneous CSF otorrhea and control groups with different BMIs. Skull base attenuation in SSCD patients did not correlate with BMI. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

  8. Efferent innervation of turtle semicircular canal cristae: comparisons with bird and mouse.

    PubMed

    Jordan, Paivi M; Fettis, Margaret; Holt, Joseph C

    2015-06-01

    In the vestibular periphery of nearly every vertebrate, cholinergic vestibular efferent neurons give rise to numerous presynaptic varicosities that target hair cells and afferent processes in the sensory neuroepithelium. Although pharmacological studies have described the postsynaptic actions of vestibular efferent stimulation in several species, characterization of efferent innervation patterns and the relative distribution of efferent varicosities among hair cells and afferents are also integral to understanding how efferent synapses operate. Vestibular efferent markers, however, have not been well characterized in the turtle, one of the animal models used by our laboratory. Here we sought to identify reliable efferent neuronal markers in the vestibular periphery of turtle, to use these markers to understand how efferent synapses are organized, and to compare efferent neuronal labeling patterns in turtle with two other amniotes using some of the same markers. Efferent fibers and varicosities were visualized in the semicircular canal of red-eared turtles (Trachemys scripta elegans), zebra finches (Taeniopygia guttata), and mice (Mus musculus) utilizing fluorescent immunohistochemistry with antibodies against choline acetyltransferase (ChAT). Vestibular hair cells and afferents were counterstained using antibodies to myosin VIIa and calretinin. In all species, ChAT labeled a population of small diameter fibers giving rise to numerous spherical varicosities abutting type II hair cells and afferent processes. That these ChAT-positive varicosities represent presynaptic release sites were demonstrated by colabeling with antibodies against the synaptic vesicle proteins synapsin I, SV2, or syntaxin and the neuropeptide calcitonin gene-related peptide. Comparisons of efferent innervation patterns among the three species are discussed. © 2015 Wiley Periodicals, Inc.

  9. Efferent innervation of turtle semicircular canal cristae: comparisons with bird and mouse

    PubMed Central

    Jordan, Paivi M.; Fettis, Margaret; Holt, Joseph C.

    2014-01-01

    In the vestibular periphery of nearly every vertebrate, cholinergic vestibular efferent neurons give rise to numerous presynaptic varicosities that target hair cells and afferent processes in the sensory neuroepithelium. Although pharmacological studies have described the postsynaptic actions of vestibular efferent stimulation in several species, characterization of efferent innervation patterns and the relative distribution of efferent varicosities among hair cells and afferents are also integral to understanding how efferent synapses operate. Vestibular efferent markers, however, have not been well characterized in the turtle, one of the animal models utilized by our laboratory. Here, we sought to identify reliable efferent neuronal markers in the vestibular periphery of turtle, to utilize these markers to understand how efferent synapses are organized, and to compare efferent neuronal labeling patterns in turtle with two other amniotes using some of the same markers. Efferent fibers and varicosities were visualized in the semicircular canal of Red-Eared Turtles (Trachemys scripta elegans), Zebra Finches (Taeniopygia guttata), and mice (Mus musculus) utilizing fluorescent immunohistochemistry with antibodies against choline acetyltransferase (ChAT). Vestibular hair cells and afferents were counterstained using antibodies to myosin VIIa and calretinin. In all species, ChAT labeled a population of small diameter fibers giving rise to numerous spherical varicosities abutting type II hair cells and afferent processes. That these ChAT-positive varicosities represent presynaptic release sites were demonstrated by colabeling with antibodies against the synaptic vesicle proteins synapsin I, SV2, or syntaxin and the neuropeptide calcitonin gene-related peptide (CGRP). Comparisons of efferent innervation patterns among the three species are discussed. PMID:25560461

  10. The effect of superior semicircular canal dehiscence on intracochlear sound pressures.

    PubMed

    Pisano, Dominic V; Niesten, Marlien E F; Merchant, Saumil N; Nakajima, Hideko Heidi

    2012-01-01

    Semicircular canal dehiscence (SCD) is a pathological opening in the bony wall of the inner ear that can result in conductive hearing loss. The hearing loss is variable across patients, and the precise mechanism and source of variability are not fully understood. Simultaneous measurements of basal intracochlear sound pressures in scala vestibuli (SV) and scala tympani (ST) enable quantification of the differential pressure across the cochlear partition, the stimulus that excites the cochlear partition. We used intracochlear sound pressure measurements in cadaveric preparations to study the effects of SCD size. Sound-induced pressures in SV and ST, as well as stapes velocity and ear canal pressure were measured simultaneously for various sizes of SCD followed by SCD patching. Our results showed that at low frequencies (<600 Hz), SCD decreased the pressure in both SV and ST, as well as differential pressure, and these effects became more pronounced as dehiscence size was increased. Near 100 Hz, SV decreased by about 10 dB for a 0.5-mm dehiscence and by 20 dB for a 2-mm dehiscence, while ST decreased by about 8 dB for a 0.5-mm dehiscence and by 18 dB for a 2-mm dehiscence. Differential pressure decreased by about 10 dB for a 0.5-mm dehiscence and by about 20 dB for a 2-mm dehiscence at 100 Hz. In some ears, for frequencies above 1 kHz, the smallest pinpoint dehiscence had bigger effects on the differential pressure (10-dB decrease) than larger dehiscences (less than 10-dB decrease), suggesting larger hearing losses in this frequency range. These effects due to SCD were reversible by patching the dehiscence. We also showed that under certain circumstances such as SCD, stapes velocity is not related to how the ear can transduce sound across the cochlear partition because it is not directly related to the differential pressure, emphasizing that certain pathologies cannot be fully assessed by measurements such as stapes velocity.

  11. The Effect of Superior Semicircular Canal Dehiscence on Intracochlear Sound Pressures

    PubMed Central

    Pisano, Dominic V.; Niesten, Marlien E.F.; Merchant, Saumil N.; Nakajima, Hideko Heidi

    2013-01-01

    Semicircular canal dehiscence (SCD) is a pathological opening in the bony wall of the inner ear that can result in conductive hearing loss. The hearing loss is variable across patients, and the precise mechanism and source of variability are not fully understood. Simultaneous measurements of basal intracochlear sound pressures in scala vestibuli (SV) and scala tympani (ST) enable quantification of the differential pressure across the cochlear partition, the stimulus that excites the cochlear partition. We used intracochlear sound pressure measurements in cadaveric preparations to study the effects of SCD size. Sound-induced pressures in SV and ST, as well as stapes velocity and ear-canal pressure were measured simultaneously for various sizes of SCD followed by SCD patching. Our results showed that at low frequencies (<600 Hz), SCD decreased the pressure in both SV and ST, as well as differential pressure, and these effects became more pronounced as dehiscence size was increased. Near 100 Hz, SV decreased about 10 dB for a 0.5 mm dehiscence and 20 dB for a 2 mm dehiscence, while ST decreased about 8 dB for a 0.5 mm dehiscence and 18 dB for a 2mm dehiscence. Differential pressure decreased about 10 dB for a 0.5 mm dehiscence and about 20 dB for a 2 mm dehiscense at 100 Hz. In some ears, for frequencies above 1 kHz, the smallest pinpoint dehiscence had bigger effects on the differential pressure (10 dB decrease) than larger dehiscenses (less than 10 dB decrease), suggesting larger hearing losses in this frequency range. These effects due to SCD were reversible by patching the dehiscence. We also showed that under certain circumstances such as SCD, stapes velocity is not related to how the ear can transduce sound across the cochlear partition because it is not directly related to the differential pressure, emphasizing that certain pathologies cannot be fully assessed by measurements such as stapes velocity. PMID:22814034

  12. The effects of perilymphatic tonicity on endolymph composition and synaptic activity at the frog semicircular canal.

    PubMed

    Rossi, M L; Ferrary, E; Martini, M; Pelucchi, B; Bernard, C; Teixeira, M; Sterkers, O; Rubbini, G; Fesce, R

    1998-07-01

    The effects of changes in perilymphatic tonicity on the semicircular canal were investigated by combining the measurements of transepithelial potential and endolymphatic ionic composition in the isolated frog posterior canal with the electrophysiological assessment of synaptic activity and sensory spike firing at the posterior canal in the isolated intact labyrinth. In the isolated posterior canal, the endolymph was replaced by an endolymph-like solution of known composition, in the presence of basolateral perilymph-like solutions of normal (230 mosmol/kg), reduced (105 mosmol/kg, low NaCl) or increased osmolality (550 mosmol/kg, Na-Gluconate added). Altered perilymphatic tonicity did not produce significant changes in endolymphatic ionic concentrations during up to 5 min. In the presence of hypotonic perilymph, decreased osmolality, K and Cl concentrations were observed at 10 min. In the presence of hypertonic perilymph, the endolymphatic osmolality began to increase at 5 min and by 10 min Na concentration had also significantly increased. On decreasing the tonicity of the external solution an immediate decline was observed in transepithelial potential, whereas hypertonicity produced the opposite effect. In the intact frog labyrinth, mEPSPs and spike potentials were recorded from single fibers of the posterior nerve in normal Ringer's (240 mosmol/kg) as well as in solutions with modified tonicity. Hypotonic solutions consistently decreased and hypertonic solutions consistently increased mEPSP and spike frequencies, independent of the species whose concentration was altered. These effects ensued within 1-2 min after the start of perfusion with the test solutions. In particular, when the tonicity was changed by varying Na concentration the mean mEPSP rate was directly related to osmolality. Size histograms of synaptic potentials were well described by single log-normal distribution functions under all experimental conditions. Hypotonic solutions (105 mosmol

  13. Mechanical properties and motion of the cupula of the human semicircular canal.

    PubMed

    Selva, Pierre; Oman, Charles M; Stone, Howard A

    2009-01-01

    The mathematical model for the dynamics of the cupula-endolymph system of the inner ear semicircular canal, as elaborated by numerous investigators, remains a foundational tool in all of vestibular physiology. Most models represent the cupula as a linear spring-like element of stiffness K=DeltaP/DeltaV, where DeltaV is the volume displaced upon application of a pressure difference DeltaP. The parameter K directly influences the long time constant of the cupula-endolymph system. Given estimates of K based on experiments, we use thick and thin bending membrane theory, and also finite-element simulations based on more realistic cupula morphologies, to estimate the human cupula's Young's modulus E approximately 5.4 Pa. We show that for a model morphology, thick bending membrane theory and finite-element predictions are in good agreement, and conclude that the morphology of the attachment of the cupula to the slope of the crista should not greatly influence the volume displacement. We note, however, that other biological materials with very low E are hydrogels that have significant viscoelastic properties. Experiments to directly measure E and investigate potential viscoelastic behavior ultimately may be needed. In addition, based on experimental images we study two other different shapes for the cupula and quantify their impact on the deflection of the cupula. We also use a three-dimensional finite-element model to analyze both the shear strain distribution and its time evolution near the sensory epithelium. We conclude that stimulation of sensory hair cells probably begins at the centre of the crista and spreads toward the periphery of the cupula and down the sides of the crista. Thus, spatio-temporal variations in the shearing stimulus are predicted to impact subsequent transduction and encoding. Finally, modeling the fluid-filled vertical channels believed to lie within the cupula, we investigate the impact of different tube diameters on the transverse displacement

  14. Superior-semicircular-canal dehiscence: effects of location, shape, and size on sound conduction.

    PubMed

    Kim, Namkeun; Steele, Charles R; Puria, Sunil

    2013-07-01

    The effects of a superior-semicircular-canal (SSC) dehiscence (SSCD) on hearing sensitivity via the air-conduction (AC) and bone-conduction (BC) pathways were investigated using a three-dimensional finite-element (FE) model of a human middle ear coupled to the inner ear. Dehiscences were modeled by removing a section of the outer bony wall of the SSC and applying a zero-pressure condition to the fluid surface thus exposed. At each frequency, the basilar-membrane velocity, vBM, was separately calculated for AC and BC stimulation, under both pre- and post-dehiscence conditions. Hearing loss was calculated as the difference in the maximum magnitudes of vBM between the pre- and post-dehiscence conditions representing a change in hearing threshold. In this study, BC excitations were simulated by applying rigid-body vibrations to the model along the directions of the (arbitrarily defined) x, y, and z axes of the model. Simulation results are consistent with previous clinical measurements on patients with an SSCD and with results from earlier lumped-element electrical-circuit modeling studies, with the dehiscence decreasing the hearing threshold (i.e., increasing vBM) by about 35 dB for BC excitation at low frequencies, while for AC excitation the dehiscence increases the hearing threshold (i.e., decreases vBM) by about 15 dB. A new finding from this study is that the initial width (defined as the width of the edge of the dehiscence where the flow of the fluid-motion wave from the oval window meets it for the first time) on the vestibular side of the dehiscence has more of an effect on vBM than the area of the dehiscence. Analyses of dehiscence effects using the FE model further predict that changing the direction of the BC excitation should have an effect on vBM, with vBM being about 20 dB lower due to BC excitation parallel to the longitudinal direction of the BM in the hook region (the x direction) as compared to excitations in other directions (y and z). BC excitation

  15. [Efficacy comparison between endolymphatic sac surgery and semicircular canal occlusion in the treatment of stage 4 Ménière disease].

    PubMed

    Han, Lin; Si, Fengzhi; Yu, Lisheng; Xia, Ruiming; Zheng, Hongwei; Jing, Yuanyuan; Ma, Xin

    2016-01-01

    To compare the vertigo controlling situation between the endolymphatic sac decompression(ELSD) and semicircular canal occlusion (SCO) in stage 4 Ménière disease. Fourteen patients who underwent endolymphatic sac decompression and 9 patients who underwent semicircular canal occlusion from 2009 to 2013 were followed. All patients has complete preoperative examination and postoperative follow-up. The vetigo control of the patients underwent endolymphatic sac decompression: completely control 35.7%; basic control 28.6%; partly control 14.3%; the vetigo control of the patients underwent semicircular canal occlusion: completely control 88.9%; basic control 11.1%. ELSD and SCO are alternative methods for the patients of stage 4. SCO has a much highter complete vertigo control rate. For the patients without practical listening, SCO is a better choice.

  16. A Multi-channel Semicircular Canal Neural Prosthesis Using Electrical Stimulation to Restore 3D Vestibular Sensation

    PubMed Central

    Della Santina, Charles C.; Migliaccio, Americo A.; Patel, Amit H.

    2009-01-01

    Bilateral loss of vestibular sensation can be disabling. Those afflicted suffer illusory visual field movement during head movements, chronic disequilibrium and postural instability due to failure of vestibulo-ocular and vestibulo-spinal reflexes. A neural prosthesis that emulates the normal transduction of head rotation by semicircular canals could significantly improve quality of life for these patients. Like the 3 semicircular canals in a normal ear, such a device should at least transduce 3 orthogonal (or linearly separable) components of head rotation into activity on corresponding ampullary branches of the vestibular nerve. We describe the design, circuit performance and in vivo application of a head-mounted, semi-implantable multi-channel vestibular prosthesis that encodes head movement in 3 dimensions as pulse-frequency-modulated electrical stimulation of 3 or more ampullary nerves. In chinchillas treated with intratympanic gentamicin to ablate vestibular sensation bilaterally, prosthetic stimuli elicited a partly compensatory angular vestibulo-ocular reflex in multiple planes. Minimizing misalignment between the axis of eye and head rotation, apparently caused by current spread beyond each electrode’s targeted nerve branch, emerged as a key challenge. Increasing stimulation selectivity via improvements in electrode design, surgical technique and stimulus protocol will likely be required to restore AVOR function over the full range of normal behavior. PMID:17554821

  17. [Benign paroxysmal positional vertigo of the horizontal canal: A multicenter study].

    PubMed

    Amor Dorado, J C; Martín, E; Arán, I; Barreira, P; Barona, R

    2006-05-01

    BPPV localized in the horizontal semicircular canal is an infrequent entity. Nowadays there are controversies about the different treatments available. The objective of this study is to present our results. A multicenter and retrospective study was performed in 31 patients diagnosed of BPPV-HSC between January 1996 and May 2004. cupulolithiasis was diagnosed in 48% on the patients. Symptoms disappeared before signs (p<0.05). Global cure rate was 85%, while relapses were 16% at one year. No relations were found between cure rate and relapses and age, gender, duration of symptoms, canalithiasis and cupulolithiasis. Our results support that there are not differences between the treatments performed in the BPPV-HSC. Symptoms disappeared before signs when canalith repositioning particles (CRP) maneuver was performed.

  18. Otolith organ or semicircular canal stimulation induces c-fos expression in unipolar brush cells and granule cells of cat and squirrel monkey.

    PubMed

    Sekerková, Gabriella; Ilijic, Ema; Mugnaini, Enrico; Baker, James F

    2005-07-01

    Immediate early gene expression in the cerebellar vermis of cats and squirrel monkeys was stimulated by prolonged whole body rotations. Continuous, earth-horizontal axis rotations that excited only otoliths or high velocity vertical axis rotations that excited only semicircular canals resulted in c-fos immunoreactive nuclei concentrated in the granular layer of lobules X and ventral IX (the nodulus and ventral uvula), which represent the medial parts of the vestibulo-cerebellum. Large clusters of labeled nuclei consisting mainly of granule cells and calretinin-positive unipolar brush cells were present in the granular layer, whereas Purkinje cell nuclei were unlabeled, and labeled basket and stellate cell nuclei were scattered in the molecular layer. In other vermal lobules there was a significant but less dense label than in the nodulus and ventral uvula. Generally, the extent of c-fos labeling of molecular layer interneurons was in relation to nuclear labeling of granular layer neurons: labeling of both basket and stellate cells accompanied nuclear labeling of neurons throughout the depth of the granular layer, whereas only stellate cells were labeled when nuclear labeling was restricted to the superficial granular layer. Yaw horizontal or roll vertical rotations each stimulated c-fos expression in the cat medial vestibulo-cerebellum to approximately the same extent. Low-velocity rotations resulted in much less c-fos expression. Similar, albeit less intense, patterns of c-fos activation were observed in monkeys. Concentrated c-fos expression in the medial vestibulo-cerebellum after exposure to a strong head velocity signal that could originate from either otolith or canal excitation suggests that granule and unipolar brush cells participate in a neuronal network for estimating head velocity, irrespective of the signal source.

  19. Divergent roles for Wnt/β-catenin signaling in epithelial maintenance and breakdown during semicircular canal formation

    PubMed Central

    Rakowiecki, Staci; Epstein, Douglas J.

    2013-01-01

    The morphogenetic program that shapes the three semicircular canals (SSCs) must be executed with extreme precision to satisfy their complex vestibular function. The SSCs emerge from epithelial outgrowths of the dorsal otocyst, the central regions of which fuse and resorb to leave three fluid-filled canals. The Wnt/β-catenin signaling pathway is active at multiple stages of otic development, including during vestibular morphogenesis. How Wnt/β-catenin functionally integrates with other signaling pathways to sculpt the SSCs and their sensory patches is unknown. We used a genetic strategy to spatiotemporally modulate canonical Wnt signaling activity during SSC development in mice. Our findings demonstrate that Wnt/β-catenin signaling functions in a multifaceted manner during SSC formation. In the early phase, Wnt/β-catenin signaling is required to preserve the epithelial integrity of the vertical canal pouch perimeter (presumptive anterior and posterior SSCs) by establishing a sensory-dependent signaling relay that maintains expression of Dlx5 and opposes expression of the fusion plate marker netrin 1. Without this Wnt signaling activity the sensory to non-sensory signaling cascade fails to be activated, resulting in loss of vestibular hair and support cells and the anterior and posterior SSCs. In the later phase, Wnt/β-catenin signaling becomes restricted to the fusion plate where it facilitates the timely resorption of this tissue. Mosaic recombination of β-catenin in small clusters of canal pouch cells prevents their resorption, causing instead the formation of ectopic SSCs. Together, these disparate functions of the Wnt/β-catenin pathway in epithelial maintenance and resorption help regulate the size, shape and number of SSCs. PMID:23487315

  20. Semicircular canal morphogenesis in the zebrafish inner ear requires the function of gpr126 (lauscher), an adhesion class G protein-coupled receptor gene

    PubMed Central

    Geng, Fan-Suo; Abbas, Leila; Baxendale, Sarah; Holdsworth, Celia J.; Swanson, A. George; Slanchev, Krasimir; Hammerschmidt, Matthias; Topczewski, Jacek; Whitfield, Tanya T.

    2013-01-01

    Morphogenesis of the semicircular canal ducts in the vertebrate inner ear is a dramatic example of epithelial remodelling in the embryo, and failure of normal canal development results in vestibular dysfunction. In zebrafish and Xenopus, semicircular canal ducts develop when projections of epithelium, driven by extracellular matrix production, push into the otic vesicle and fuse to form pillars. We show that in the zebrafish, extracellular matrix gene expression is high during projection outgrowth and then rapidly downregulated after fusion. Enzymatic disruption of hyaluronan in the projections leads to their collapse and a failure to form pillars: as a result, the ears swell. We have cloned a zebrafish mutant, lauscher (lau), identified by its swollen ear phenotype. The primary defect in the ear is abnormal projection outgrowth and a failure of fusion to form the semicircular canal pillars. Otic expression of extracellular matrix components is highly disrupted: several genes fail to become downregulated and remain expressed at abnormally high levels into late larval stages. The lau mutations disrupt gpr126, an adhesion class G protein-coupled receptor gene. Expression of gpr126 is similar to that of sox10, an ear and neural crest marker, and is partially dependent on sox10 activity. Fusion of canal projections and downregulation of otic versican expression in a hypomorphic lau allele can be restored by cAMP agonists. We propose that Gpr126 acts through a cAMP-mediated pathway to control the outgrowth and adhesion of canal projections in the zebrafish ear via the regulation of extracellular matrix gene expression. PMID:24067352

  1. Diagnostic performance of reformatted isotropic thin-section helical CT images in the detection of superior semicircular canal dehiscence.

    PubMed

    Sparacia, Gianvincenzo; Iaia, Alberto

    2017-06-01

    Purpose The purpose of this article is to assess the diagnostic performance of computed tomography (CT) reformatted images for detection of superior semicircular canal (SSC) dehiscence. Material and methods Forty-two patients, with sound- and/or pressure-induced vestibular symptoms, and 42 control participants underwent helical CT examination with a highly collimated beam (0.5 mm). Reformatted images of the vestibular labyrinth were obtained in the standard axial and coronal planes (group A images), and in a plane parallel and perpendicular to the SSC (group B images). Diagnostic performance obtained by evaluating the group A images alone and the group B images alone was analyzed by using the area under the receiver operating characteristic curve (AUC). Results The diagnostic performance of group A images was AUC = 0.929 with an overall accuracy of 92.9%. The diagnostic performance of group B images was AUC = 0.988 with an overall accuracy of 98.8%. The evaluation of group B images alone showed an improved diagnostic performance over the group A images alone. Conclusion Thin-section 0.5-mm collimation CT with reformatted images oriented in the plane parallel and perpendicular to the SSC improves diagnostic accuracy in assessing for SSC dehiscence in comparison to CT images with reconstructions limited to traditional axial and coronal planes.

  2. Vestibular implantation and longitudinal electrical stimulation of the semicircular canal afferents in human subjects

    PubMed Central

    Ling, Leo; Nie, Kaibao; Jameyson, Elyse; Phillips, Christopher M.; Nowack, Amy L.; Golub, Justin S.; Rubinstein, Jay T.

    2015-01-01

    Animal experiments and limited data in humans suggest that electrical stimulation of the vestibular end organs could be used to treat loss of vestibular function. In this paper we demonstrate that canal-specific two-dimensionally (2D) measured eye velocities are elicited from intermittent brief 2 s biphasic pulse electrical stimulation in four human subjects implanted with a vestibular prosthesis. The 2D measured direction of the slow phase eye movements changed with the canal stimulated. Increasing pulse current over a 0–400 μA range typically produced a monotonic increase in slow phase eye velocity. The responses decremented or in some cases fluctuated over time in most implanted canals but could be partially restored by changing the return path of the stimulation current. Implantation of the device in Meniere's patients produced hearing and vestibular loss in the implanted ear. Electrical stimulation was well tolerated, producing no sensation of pain, nausea, or auditory percept with stimulation that elicited robust eye movements. There were changes in slow phase eye velocity with current and over time, and changes in electrically evoked compound action potentials produced by stimulation and recorded with the implanted device. Perceived rotation in subjects was consistent with the slow phase eye movements in direction and scaled with stimulation current in magnitude. These results suggest that electrical stimulation of the vestibular end organ in human subjects provided controlled vestibular inputs over time, but in Meniere's patients this apparently came at the cost of hearing and vestibular function in the implanted ear. PMID:25652917

  3. Bedside therapeutic experiences with horizontal canal benign paroxysmal positional vertigo (cupulolithiasis).

    PubMed

    Boleas-Aguirre, María Soledad; Pérez, Nicolás; Batuecas-Caletrío, Angel

    2009-11-01

    After forced prolonged position type one (FPP-one) and the appropriate repositioning maneuvers, or FPP-two, 95.45% of patients with cupulolithiasis of the horizontal semicircular canal benign paroxysmal positional vertigo (HSC-BPPV).were symptom-free. To treat patients with cupulolithiasis of the HSC-BPPV. This was a prospective study including 22 subjects with HSC-BPPV (cupulolithiasis) based on apogeotropic direction-changing positional nystagmus (apo-DCPN). Patients adopted FPP-one, which means lying down on the side of the weaker nystagmus during nightly rest for 2 weeks. If apo-DCPN persisted, subjects adopted type two FPP (FPP-two), which means lying on the strongest nystagmus side during nightly rest for 2 weeks. No vertigo or nystagmus was observed in 15 subjects after FPP-one. One subject experienced geotropic DCPN (geo-DCPN), two subjects had posterior BPPV, and another had superior BPPV. Three subjects had persistent apo-DCPN and they were subjected to FPP-two. After that, no vertigo or nystagmus was detected in two subjects. Apo-DCPN persisted in the other remaining subject after FPP-two.

  4. Dizziness handicap after cartilage cap occlusion for superior semicircular canal dehiscence.

    PubMed

    Bogle, Jamie M; Lundy, Larry B; Zapala, David A; Copenhaver, Amanda

    2013-01-01

    To evaluate the change in self-reported dizziness handicap after surgical repair using the cartilage cap occlusion technique in cases of superior canal dehiscence (SCD). Repeated measures, retrospective chart review. Tertiary referral center. Twenty patients over a 2-year period who underwent surgical repair of SCD using the cartilage cap occlusion technique. Therapeutic. Preoperative and postoperative Dizziness Handicap Inventory (DHI) questionnaires were completed (median, interquartile range). Preoperative (48, 28-56) and postoperative (33, 19-50) total scores were not significantly different. Scores for patients with moderate/severe preoperative DHI scores (DHI, >30; n = 14) demonstrated significant change (p = 0.001, Wilcoxon paired sample test), whereas those with mild scores did not (DHI, ≤ 30; n = 6; p = 0.67). Change in DHI score is variable. As described by DHI score, patients with higher preoperative handicap may demonstrate significant improvement after surgery, whereas those with mild handicap may not. These results are similar to previous reports and indicate that the cartilage cap occlusion technique may provide an alternative to middle fossa craniotomy approach for surgical management of symptomatic SCD.

  5. The variability of inner ear orientation in saurischian dinosaurs: testing the use of semicircular canals as a reference system for comparative anatomy.

    PubMed

    Marugán-Lobón, Jesús; Chiappe, Luis M; Farke, Andrew A

    2013-01-01

    The vestibular system of the inner ear houses three semicircular canals-oriented on three nearly-orthogonal planes-that respond to angular acceleration stimuli. In recent years, the orientation of the lateral semicircular canal (LSC) has been regularly used to determine skull orientations for comparative purposes in studies of non-avian dinosaurs. Such orientations have been inferred based on fixing the LSC to a common set of coordinates (parallel to the Earth's horizon), given that the orientation to gravity of this sensory system is assumed constant among taxa. Under this assumption, the LSC is used as a baseline (a reference system) both to estimate how the animals held their heads and to describe craniofacial variation among dinosaurs. However, the available data in living birds (extant saurischian dinosaurs) suggests that the orientation of the LSC in non-avian saurischian dinosaurs could have been very variable and taxon-specific. If such were the case, using the LSC as a comparative reference system would cause inappropriate visual perceptions of craniofacial organization, leading to significant descriptive inconsistencies among taxa. Here, we used Procrustes methods (Geometric Morphometrics), a suite of analytical tools that compares morphology on the basis of shared landmark homology, to show that the variability of LSC relative to skull landmarks is large (ca. 50°) and likely unpredictable, thus making it an inconsistent reference system for comparing and describing the skulls of saurischian (sauropodomorph and theropod) dinosaurs. In light of our results, the lateral semicircular canal is an inconsistent baseline for comparative studies of craniofacial morphology in dinosaurs.

  6. [Canalith repositioning maneuver: proposal of a new therapy for benign paroxysmal positional vertigo of the posterior semicircular canal].

    PubMed

    D'Onofrio, F; Costa, G; Mazzone, A; Barillari, U

    1998-10-01

    A new therapy is proposed for the treatment of Benign Paroxysmal Positional Vertigo (B.P.P.V.) of the Posterior Semicircular Canal (P.S.C.): the Canalith Repositioning Maneuver (C.R.M.). The need for a new maneuver to treat B.P.P.V. of the P.S.C. arises from the difficulties encountered in daily practice, under particular conditions (i.e. elderly, obese, traumatized patients and in the presence of rachis pain, etc.), to perform the most common rehabilitative techniques such as the Semont Maneuver and Epley's Canalith Repositioning Procedure (C.R.P.). The results achieved using this new technique on a group of 47 consecutive out-patients are presented and compared to those achieved using the Semont Maneuver in an analogous group of 23 patients. C.R.M. and the Semont Maneuver were performed once per treatment session and all patients were checked every 3 days until the symptoms of B.P.P.V. disappeared. Thereafter they were invited to return for check-up if signs of vertigo returned (follow-up 6-25 months). The two techniques proved equally effective: 87.5% of the cases were resolved with C.R.M., 82.6% with the Semont Maneuver. However, the C.R.M. provided other advantages as it resolved the problem immediately (i.e. in a single session) in 81% of the cases vs. 68.4% for the Semont Maneuver. In view of the Canalith theory, the action mechanism envisaged for all three maneuvers--C.R.M., the Semont Maneuver and the Epley C.R.P.--can be explained assuming that the canalith passes from the ampullar to the non ampullar branch of the (P.S.C.) passing finally through the Common Duct and into the Utricle. C.R.M. is a specific treatment for the B.P.P.V. of the P.S.C. and is simple to perform, well tolerated and quite effective. It is indicated in all cases of B.P.P.V. of the P.S.C. both as initial treatment and as alternative to other treatment methods which have proved ineffective or difficult to perform. Indeed, in therapy it is best to be quite skilled in more than one

  7. Horizontal vestibuloocular reflex evoked by high-acceleration rotations in the squirrel monkey. II. Responses after canal plugging

    NASA Technical Reports Server (NTRS)

    Lasker, D. M.; Backous, D. D.; Lysakowski, A.; Davis, G. L.; Minor, L. B.

    1999-01-01

    The horizontal angular vestibuloocular reflex (VOR) evoked by high-frequency, high-acceleration rotations was studied in four squirrel monkeys after unilateral plugging of the three semicircular canals. During the period (1-4 days) that animals were kept in darkness after plugging, the gain during steps of acceleration (3, 000 degrees /s(2), peak velocity = 150 degrees /s) was 0.61 +/- 0.14 (mean +/- SD) for contralesional rotations and 0.33 +/- 0.03 for ipsilesional rotations. Within 18-24 h after animals were returned to light, the VOR gain for contralesional rotations increased to 0. 88 +/- 0.05, whereas there was only a slight increase in the gain for ipsilesional rotations to 0.37 +/- 0.07. A symmetrical increase in the gain measured at the plateau of head velocity was noted after animals were returned to light. The latency of the VOR was 8.2 +/- 0. 4 ms for ipsilesional and 7.1 +/- 0.3 ms for contralesional rotations. The VOR evoked by sinusoidal rotations of 0.5-15 Hz, +/-20 degrees /s had no significant half-cycle asymmetries. The recovery of gain for these responses after plugging was greater at lower than at higher frequencies. Responses to rotations at higher velocities for frequencies >/=4 Hz showed an increase in contralesional half-cycle gain, whereas ipsilesional half-cycle gain was unchanged. A residual response that appeared to be canal and not otolith mediated was noted after plugging of all six semicircular canals. This response increased with frequency to reach a gain of 0.23 +/- 0.03 at 15 Hz, resembling that predicted based on a reduction of the dominant time constant of the canal to 32 ms after plugging. A model incorporating linear and nonlinear pathways was used to simulate the data. The coefficients of this model were determined from data in animals with intact vestibular function. Selective increases in the gain for the linear and nonlinear pathways predicted the changes in recovery observed after canal plugging. An increase in gain of

  8. Horizontal vestibuloocular reflex evoked by high-acceleration rotations in the squirrel monkey. II. Responses after canal plugging

    NASA Technical Reports Server (NTRS)

    Lasker, D. M.; Backous, D. D.; Lysakowski, A.; Davis, G. L.; Minor, L. B.

    1999-01-01

    The horizontal angular vestibuloocular reflex (VOR) evoked by high-frequency, high-acceleration rotations was studied in four squirrel monkeys after unilateral plugging of the three semicircular canals. During the period (1-4 days) that animals were kept in darkness after plugging, the gain during steps of acceleration (3, 000 degrees /s(2), peak velocity = 150 degrees /s) was 0.61 +/- 0.14 (mean +/- SD) for contralesional rotations and 0.33 +/- 0.03 for ipsilesional rotations. Within 18-24 h after animals were returned to light, the VOR gain for contralesional rotations increased to 0. 88 +/- 0.05, whereas there was only a slight increase in the gain for ipsilesional rotations to 0.37 +/- 0.07. A symmetrical increase in the gain measured at the plateau of head velocity was noted after animals were returned to light. The latency of the VOR was 8.2 +/- 0. 4 ms for ipsilesional and 7.1 +/- 0.3 ms for contralesional rotations. The VOR evoked by sinusoidal rotations of 0.5-15 Hz, +/-20 degrees /s had no significant half-cycle asymmetries. The recovery of gain for these responses after plugging was greater at lower than at higher frequencies. Responses to rotations at higher velocities for frequencies >/=4 Hz showed an increase in contralesional half-cycle gain, whereas ipsilesional half-cycle gain was unchanged. A residual response that appeared to be canal and not otolith mediated was noted after plugging of all six semicircular canals. This response increased with frequency to reach a gain of 0.23 +/- 0.03 at 15 Hz, resembling that predicted based on a reduction of the dominant time constant of the canal to 32 ms after plugging. A model incorporating linear and nonlinear pathways was used to simulate the data. The coefficients of this model were determined from data in animals with intact vestibular function. Selective increases in the gain for the linear and nonlinear pathways predicted the changes in recovery observed after canal plugging. An increase in gain of

  9. Video Head Impulse Tests with a Remote Camera System: Normative Values of Semicircular Canal Vestibulo-Ocular Reflex Gain in Infants and Children

    PubMed Central

    Wiener-Vacher, Sylvette R.; Wiener, Sidney I.

    2017-01-01

    The video head impulse test (VHIT) is widely used to identify semicircular canal function impairments in adults. But classical VHIT testing systems attach goggles tightly to the head, which is not tolerated by infants. Remote video detection of head and eye movements resolves this issue and, here, we report VHIT protocols and normative values for children. Vestibulo-ocular reflex (VOR) gain was measured for all canals of 303 healthy subjects, including 274 children (aged 2.6 months–15 years) and 26 adults (aged 16–67). We used the Synapsys® (Marseilles, France) VHIT Ulmer system whose remote camera measures head and eye movements. HITs were performed at high velocities. Testing typically lasts 5–10 min. In infants as young as 3 months old, VHIT yielded good inter-measure replicability. VOR gain increases rapidly until about the age of 6 years (with variation among canals), then progresses more slowly to reach adult values by the age of 16. Values are more variable among very young children and for the vertical canals, but showed no difference for right versus left head rotations. Normative values of VOR gain are presented to help detect vestibular impairment in patients. VHIT testing prior to cochlear implants could help prevent total vestibular loss and the resulting grave impairments of motor and cognitive development in patients with residual unilateral vestibular function. PMID:28936193

  10. Vestibular evoked potentials from the vertical semicircular canals in humans evoked by roll-axis rotation in microgravity and under 1-G.

    PubMed

    Loose, Rainer; Probst, Thomas; Tucha, Oliver; Bablok, Erhard; Aschenbrenner, Steffen; Lange, Klaus W

    2002-08-21

    Vestibular evoked potentials during rotation of human subjects around their naso-occipital roll-axis were recorded. The effect of stimulating the vertical semicircular canals and otolithic stimulation was investigated by comparing the evoked potentials obtained under the 1-G condition with those recorded in microgravity conditions. Subjects lay on their side with the head in the center of rotation and were tilted feet upward (roll up) and back into the lying position (roll down). The microgravity environment was created by parabolic flight maneuvers. In microgravity, transient bell-shaped negativity was recorded for roll up and down motion. In the 1-G condition the potentials were superimposed on sustained components, probably due to additional otolithic stimulation. It seems to be possible to separate the evoked responses in a transient canal response and a sustained otolithic response. The results are encouraging with respect to the goal of developing a tool for the selective assessment of canal and otolithic responses of the vestibular system. Copyright 2002 Elsevier Science B.V.

  11. Concurrent posterior semicircular canal benign paroxysmal positional vertigo in patients with ipsilateral sudden sensorineural hearing loss: is it caused by otolith particles?

    PubMed

    Kim, Chang-Hee; Shin, Jung Eun; Park, Hong Ju; Koo, Ja-Won; Lee, Jun Ho

    2014-04-01

    The etiology of benign paroxysmal positional vertigo (BPPV) is still elusive even though detached otolith particles from the utricular macula are generally thought to be responsible for the pathogenesis of BPPV. Sudden sensorineural hearing loss (SSNHL), of which the etiology is also idiopathic in most cases, may accompany concurrent BPPV. This uncommon condition of concurrent BPPV with SSNHL has been assumptively explained as selective damage of the cochlea and the utricle due to viral neurolabyrinthitis. Recently, radiological evidences that inner ear hemorrhage is observed in patients with SSNHL accompanied by severe vertigo have been reported. The basic hypothesis for this study is that blood debris in the endolymphatic fluid due to inner ear hemorrhage is one of the causes of concurrent posterior semicircular canal (PSCC) BPPV in patient with ipsilateral SSNHL. In this report, we will outline the clinical findings of 4 patients with PSCC BPPV with SSNHL, and present an experimental results using whole blood in artificial endolymph to evaluate the hypothesis.

  12. Bilateral posterior semi-circular canal obliteration surgery for refractory benign paroxysmal positional vertigo (BPPV) in three patients.

    PubMed

    Das, Sudip; Rea, Peter A

    2016-02-15

    Benign paroxysmal positional vertigo (BPPV) is a common cause of peripheral vestibular disorder(1) characterised by a short lasting rotatory vertigo triggered by movement of the head. Unilateral posterior canal plugging has become an accepted, if uncommonly used, method of treating intractable cases. However there is very limited experience of bilateral posterior canal plugging. When the current series of cases began, there were no cases reported in the literature. Two small series have since been reported from America and Australia.(2,3) This is the first published UK series to our knowledge. This article is protected by copyright. All rights reserved.

  13. Efficacy of cervical and ocular vestibular-evoked myogenic potentials in evaluation of benign paroxysmal positional vertigo of posterior semicircular canal.

    PubMed

    Singh, Niraj Kumar; Apeksha, Kumari

    2016-09-01

    Benign paroxysmal positional vertigo (BPPV) constitutes a major proportion of the population with peripheral vestibulopathies. Although the freely floating otoconia within the semicircular canals is responsible for the symptoms of BPPV, the source of the otoconia debris is mainly believed to be the otolith organs. Therefore, the pathology in either or both the otolith organs appears a logical proposition. Cervical and ocular vestibular-evoked myogenic potentials (cVEMP and oVEMP), being the tests for functional integrity of the otolith organs, appear promising for investigating otolith involvement in BPPV. While recent evidences are suggestive of equivocal findings for cVEMP, there are only a few studies on oVEMP. Additionally, both these potentials have never been explored in the same set of individuals with BPPV. Therefore, the present study aimed to evaluate the functional integrity of the otolith organs through cVEMP and oVEMP in individuals with posterior canal BPPV. Thirty-one individuals with unilateral posterior canal BPPV and 31 age- and gender-matched healthy controls underwent 500 Hz tone-burst-evoked cVEMP and oVEMP. The results demonstrated no significant group difference on any of the cVEMP parameters (p > 0.05). A similar trend was noticed for the latency-related parameters of oVEMP. However, the peak-to-peak amplitude was significantly smaller in the affected ears of individuals with BPPV than their unaffected ears and the ears of healthy controls (p < 0.05). The BPPV group showed significantly higher inter-aural amplitude difference ratio than the healthy controls (p < 0.05). Further, the sensitivity and specificity of oVEMP were also found to be far superior to those of cVEMP. Thus, the outcome of the present study revealed involvement of utricle rather than saccule in posterior canal BPPV, and therefore, oVEMP appears to be better suited to clinical investigation than cVEMP in individuals with posterior canal BPPV.

  14. Insights into horizontal canal benign paroxysmal positional vertigo from a human case report.

    PubMed

    Aron, Margaret; Bance, Manohar

    2013-12-01

    For horizontal canal benign paroxysmal positional vertigo, determination of the pathologic side is difficult and based on many physiological assumptions. This article reports findings on a patient who had one dysfunctional inner ear and who presented with horizontal canal benign paroxysmal positional vertigo, giving us a relatively pure model for observing nystagmus arising in a subject in whom the affected side is known a priori. It is an interesting human model corroborating theories of nystagmus generation in this pathology and also serves to validate Ewald's second law in a living human subject. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

  15. Long-term outcomes of a transmastoid lateral semicircular canal approach to congenital CSF otorrhea in children associated with recurrent meningitis and severe inner ear malformation.

    PubMed

    Wang, Jie; Li, Yongxin; Chen, Shubin; Hao, Xinping

    2016-08-01

    To investigate the long-term effectiveness of transmastoid lateral semicircular canal approach (TMLSCCA) to repair cerebrospinal fluid (CSF) leakage in children associated with recurrent meningitis and severe congenital inner malformation. A retrospective study was conducted in a university hospital, academic medical center. Fifteen children with recurrent meningitis, secondary to severe congenital inner ear malformation, were included in the study. All of them had CSF associated otorrhea and treated using TLSCCA to repair CSF otorrhea by packing the vestibule with muscle and fascia. Observation of the status of postoperative CSF leakage, recurrence of meningitis and complication were conducted. None of the cases had recurrent meningitis and CSF leakage after their TLSCCA procedure in the follow-up period of 1-8.5 years. One case presented with transient facial nerve paralysis and completely recovered 3 months later. TLSCCA for CSF otorrhea in children with recurrent meningitis secondary to congenital inner ear malformation is an alternative approach that offers some advantages. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. The correlated blanching of synaptic bodies and reduction in afferent firing rates caused by transmitter-depleting agents in the frog semicircular canal

    NASA Technical Reports Server (NTRS)

    Guth, P.; Norris, C.; Fermin, C. D.; Pantoja, M.

    1993-01-01

    Synaptic bodies (SBs) associated with rings of synaptic vesicles and well-defined, pre- and post-synaptic membrane structures are indicators of maturity in most hair cell-afferent nerve junctions. The role of the SBs remains elusive despite several experiments showing that they may be involved in storage of neurotransmitter. Our results demonstrate that SBs of the adult posterior semicircular canal (SCC) cristae hair cells become less electron dense following incubation of the SCC with the transmitter-depleting drug tetrabenazine (TBZ). Objective quantification and comparison of the densities of the SBs in untreated and TBZ-treated frog SCC demonstrated that TBZ significantly decreased the electron density of SBs. This reduction in electron density was accompanied by a reduction in firing rates of afferent fibers innervating the posterior SCC. A second transmitter-depleting drug, guanethidine, previously shown to reduce the electron density of hair cell SBs, also reduced the firing rates of afferent fibers innervating the posterior SCC. In contrast, the electron density of dense granules (DG), similar in size and shape to synaptic bodies (SB) in hair cells, did not change after incubation in TBZ, thus indicating that granules and SBs are not similar in regard to their electron density. The role of SBs in synaptic transmission and the transmitter, if any, stored in the SBs remain unknown. Nonetheless, the association of the lessening of electron density with a reduction in afferent firing rate provides impetus for the further investigation of the SB's role in neurotransmission.

  17. [Analysis of field potentials in the postcruciate dimple evoked by stimulation of the ampullary nerve of the posterior semicircular canal in cats].

    PubMed

    Sakuma, A

    1990-05-01

    Field potentials evoked by stimulation of the posterior semicircular canal nerve (PCN) were studied in the postcruciate dimple (PCD) in anesthetized cats. When weak stimulation was provided, field potentials composed of 3 components of small positive, large positive and large negative waves were observed on the surface of the PCD. The field potentials could be observed at the stimulus intensity weaker than 1.5 x N1T. The latencies of initiation of the 3 components were 2.32 +/- 0.75 (mean +/- S.D.; n = 37), 3.75 +/- 0.92 (mean +/- S.D.; n = 99) and 9.34 +/- 2.81 (mean +/- S.D.; n = 101), respectively. The large positive wave of the maximum amplitude was recorded in the lateral part of the PCD. In this point, the large and small positive waves reversed their polarity at the layer III and V, respectively, which located about 500 microns and 1000 microns deep from the surface. Stimulations of the whole vestibular nerve (WVN) and the deep radial nerve (DR) shared response areas of field potentials. These findings agreed with the previous results as to a neuronal convergence of the somatic and vestibular inputs in the cat.

  18. Sensorineural hearing loss: there is no correlation with isolated dysplasia of the lateral semi-circular canal on temporal bone CT.

    PubMed

    Yamashita, Koji; Yoshiura, Takashi; Hiwatashi, Akio; Tuvshinjargal, Dashjamts; Kamano, Hironori; Inoguchi, Takashi; Honda, Hiroshi

    2011-03-01

    Inner ear malformations may cause sensorineural hearing loss (SNHL). However, the correlation between the small lateral semi-circular canal (LSCC) and SNHL is controversial. To determine whether there is a correlation between the two using CT-based measurement. We retrospectively reviewed the high-resolution CT images of the temporal bone obtained from consecutive patients. A total 136 ears of 68 patients (25 men and 43 women; age range 20-85 years, mean 49.8 years) were included in this study. Patients who were clinically suspected to have otosclerosis were also excluded. Two radiologists independently measured the width and cross-sectional area of the bony island of LSCC. We evaluated the correlation between LSCC bone island width or cross-sectional area and hearing level in all cases using Pearson correlation co-efficients. In addition, we compared hearing levels among the patient group with normal-sized LSCC (≧mean-SD), small LSCC ( 0.05). No significant difference in hearing levels were found among groups of the normal-sized, small and very small LSCC (P > 0.05). We conclude that there is no correlation between isolated small LSCC and SNHL.

  19. Differentiation of migrainous positional vertigo (MPV) from horizontal canal benign paroxysmal positional vertigo (HC-BPPV).

    PubMed

    Roberts, Richard A; Gans, Richard E; Kastner, Allison H

    2006-04-01

    This article presents an approach to differentiation of migrainous positional vertigo (MPV) from horizontal canal benign paroxysmal positional vertigo (HC-BPPV). Such an approach is essential because of the difference in intervention between the two disorders in question. Results from evaluation of the case study presented here revealed a persistent ageotropic positional nystagmus consistent with MPV or a cupulolithiasis variant of HC-BPPV. The patient was treated with liberatory maneuvers to remove possible otoconial debris from the horizontal canal in an attempt, in turn, to provide further diagnostic information. There was no change in symptoms following treatment for HC-BPPV. This case was diagnosed subsequently as MPV, and the patient was referred for medical intervention. Treatment has been successful for 22 months. Incorporation of HC-BPPV treatment, therefore, may provide useful information in the differential diagnosis of MPV and the cupulolithiasis variant of HC-BPPV.

  20. Nystagmus intensity and direction in bow and lean test: an aid to diagnosis of lateral semicircular canal benign paroxysmal positional vertigo.

    PubMed

    Marcelli, V

    2016-12-01

    The objective was to evaluate nystagmus intensity and direction (NID) during bow and lean test (BLT) in subjects suffering from idiopathic lateral semicircular canal benign paroxysmal positional vertigo (LSC-BPPV), in order to differentiate between the geotropic and the apogeotropic form and to determine the affected ear before using classic diagnostic procedures. The BLT was performed in 32 subjects affected by LSC-BPPV. "Nystagmus intensity" evaluation allows distinguishing the geotropic variant from the apogeotropic one, while the "nystagmus direction" allows identification of the side. In particular, a more intense nystagmus in the bow position compared to the lean position indicates an ampullipetal flow caused by the presence of free-floating particles in the non-ampullary arm, and is suggestive of geotropic form. In this case, if the nystagmus in the bow position is left beating, the free-floating particles necessarily occupy the left LSC non-ampullary arm, while a right-beating nystagmus indicates the right LSC involvement. In contrast, a more intense nystagmus in the lean position compared to the bow position indicates an ampullifugal flow due to the presence of particles adherent to the cupula (cupulolithiasis) or free-floating in the ampullary arm (canalolithiasis), suggesting an apogeotropic form. In this situation, if the nystagmus in the lean position is left beating, the particles are in the left LSC ampullar arm or are coated on the left LSC cupula; vice versa, a right-beating nystagmus in the lean position is suggestive of the involvement of the right LSC. As a general rule, in both forms the direction of the more intense nystagmus points to the affected side. "NID-BLT" was effective in identifying the form and the side in 22/28 subjects (79% of the study population). The proper execution and interpretation of the "NID-BLT" helps to establish the form (geotropic versus apogeotropic) and side (right versus left) in most cases of LSC-BPPV. Unlike

  1. Conversion of canalolithiasis to cupulolithiasis in the course of a horizontal benign paroxysmal positional vertigo case.

    PubMed

    Psillas, George; Vital, Iosif; Rachovitsas, Dimitrios; Vital, Victor; Tsalighopoulos, Miltiadis

    2011-01-01

    The benign paroxysmal positional vertigo of the horizontal semicircular canal is manifested with either geotropic or apogeotropic horizontal nystagmus. A 61-year-old male patient who experienced repeated episodes of positional vertigo is presented in this study. The vertigo was reported to be more severe while rotating his head to the left and then to the right. The initial examination revealed a geotropic purely horizontal nystagmus at the lateral positions of the head compatible with canalolithiasis of the left horizontal semicircular canal. In this case, the otoconia debris migrates from the vestibule into the horizontal semicircular canal through its nonampullary end, where they float freely (canalolithiasis). Five days later, the geotropic nystagmus transformed to apogeotropic. Thus, it may be assumed that the otoconia debris adhered to the cupula and converted the canalolithiasis to cupulolithiasis of the horizontal semicircular canal on the same side. With rotation of the head to the left while the patient was in the supine position, gravity causes the weighted cupula to deflect ampullofugally, resulting in apogeotropic nystagmus; the opposite was noticed when the head was rotated to the right. The so-called barbecue maneuver was initially effective curing the geotropic form of the condition and consequently the modified Semont maneuver for the apogeotropic form. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Treatment of horizontal canal benign paroxysmal positional vertigo: a new rehabilitation technique.

    PubMed

    Testa, D; Castaldo, G; De Santis, C; Trusio, A; Motta, G

    2012-01-01

    The aim of this study was to evaluate the effectiveness of a new technical variant applied to the Gufoni's manoeuvre, in the treatment of horizontal canal benign paroxysmal positional vertigo (HSC-BPPV). 87 patients with BPPV of HSC (55 women and 32 men), aged between 21 and 80 years, were randomized either to modified Gufoni's manoeuvre or to the Gufoni's manoeuvre. 93% of patients treated with modified Gufoni's manoeuvre was cured after the first treatment session, of which only 2% had a conversion into PSC-BPPV, while the Gufoni's manoeuvre led to a symptoms resolution in 88% of cases, of which 16% had a conversion into PSC-BPPV. Therefore, the modified Gufoni's manoeuvre shows the same effectiveness in the resolution of symptoms of Gufoni's manoeuvre, but it appears more effective than the latter to reduce the percentage of conversion of the HSC-BPPV into PSC-BPPV (χ(2) = 6.13, P = 0.047).

  3. [Response of efferent vestibular fibers to horizontal rotation in frogs (Rana esculenta L.)].

    PubMed

    Caston, J; Gribenski, A

    1975-01-01

    The activity of efferent vestibular fibres has been recorded on the nerve of the left vertical anterior semicircular canal detached from its ampulla during rotations in the horizontal plane. Different types of responses have been found; they are noted in table I and pictured on fig. 2.

  4. Canals

    ERIC Educational Resources Information Center

    Winkleman, Michael

    1974-01-01

    In the mid-1800's, the canal system in the U.S. was thriving. But, by the end of that century, roads and railways had replaced these commercial thoroughfares. Renewed interest in the abandoned canals is now resulting in renovation and ecological site development in Pennsylvania and New Jersey. (MA)

  5. Canals

    ERIC Educational Resources Information Center

    Winkleman, Michael

    1974-01-01

    In the mid-1800's, the canal system in the U.S. was thriving. But, by the end of that century, roads and railways had replaced these commercial thoroughfares. Renewed interest in the abandoned canals is now resulting in renovation and ecological site development in Pennsylvania and New Jersey. (MA)

  6. Persistent Direction-Fixed Nystagmus Following Canalith Repositioning Maneuver for Horizontal Canal BPPV: A Case of Canalith Jam.

    PubMed

    Chang, Young-Soo; Choi, Jeesun; Chung, Won-Ho

    2014-06-01

    The authors report a 64-year-old man who developed persistent direction fixed nystagmus after a canalith repositioning maneuver for horizontal canal benign paroxysmal positional vertigo (HC-BPPV). The patient was initially diagnosed with right HC-BPPV given that the Dix-Hallpike test showed geotropic horizontal nystagmus that was more pronounced on the right side, although the roll test did not show any positional nystagmus. The patient was treated with a canalith repositioning maneuver (Lempert maneuver). The next day, the patient experienced a different character of dizziness, and left-beating spontaneous nystagmus regardless of head position was observed. After a forced prolonged left decubitus and frequent head shaking, his symptoms and nystagmus resolved. This condition, referred to as canalith jam, can be a complication after the repositioning maneuver in patients with BPPV. Atypical positional tests suggest that abnormal canal anatomy could be the underlying cause of canalith jam.

  7. Analysis of afferent responses from isolated semicircular canal of the guitarfish using rotational acceleration white-noise inputs. II. Estimation of linear system parameters and gain and phase spectra.

    PubMed

    O'Leary, D P; Honrubia, V

    1976-05-01

    Quantitative estimates were computed for exponential coefficients and rate constants contributing to afferent unit impulse responses obtained from bundles innervating specific regions of the semicircular canal. The grouping of these estimates into specific response classes provided quantitative correlations with specific anatomical regions of innervation of the crista. Linear system gain and phase spectra were computed also, by applying Fourier transformations to unit impulse responses, for purposes of comparison with previous studies employing frequency domain analyses. Responses fitted by third-order linear system equations were specific to afferents innervating the crest and transition regions of the crista; whereas those fitted by overdamped, second-order equations were specific to afferents innervating the slopes and transition crista regions. It was concluded that strictly mechanical models of the transduction process are inadequate to account for the diverse and spatially distributed classes of observed responses and, moreover, structural features such as different hair cell types or efferent innervation effects could be excluded as inoperative in this preparation. The alternative hypothesis was suggested that certain of the observed subcomponents could be direct reflections of the initial mechanical stimulus, but that other subcomponents were reflections of more complex filtering mechanisms operating at the cellular or synaptic levels.

  8. Natural history of horizontal canal benign paroxysmal positional vertigo is truly short.

    PubMed

    Shim, Dae Bo; Ko, Kyung Min; Lee, Joon Hee; Park, Hong Ju; Song, Mee Hyun

    2015-01-01

    The objective of the study is to characterize the natural course of positional vertigo and nystagmus in patients with horizontal canal benign paroxysmal positional vertigo (h-BPPV) and to analyze the difference in the natural course between the two variants of h-BPPV. We conducted a prospective study in 106 patients with geotropic type h-BPPV [h-BPPV (Geo)] (n = 43) and apogeotropic type h-BPPV [h-BPPV (Apo)] (n = 63) who agreed and signed the written informed consent of no treatment. All patients were asked to answer a detailed interview about the onset time of positional vertigo and to visit the hospital every 1-3 days. At every visit, they were interviewed about cessation time of positional vertigo and positional nystagmus was assessed. The mean period ± SD between the onset and remission of vertigo in the h-BPPV (Geo) was 6.7 ± 6.3 days, whereas that in the h-BPPV (Apo) was 3.7 ± 4.1 days. In addition, the mean period ± SD from the initial diagnosis to the disappearance of positional nystagmus in the h-BPPV (Geo) was 4.7 ± 3.9 days, whereas that in the h-BPPV (Apo) was 4.4 ± 5.0 days. Although the duration until natural remission of positional nystagmus did not differ between the two variants of h-BPPV, the remission of vertigo occurred faster in h-BPPV (Apo) than h-BPPV (Geo) (p < 0.05). The natural course of h-BPPV is much shorter than that indicated in previous reports. The positional vertigo disappeared faster in the h-BPPV (Apo) compared to the h-BPPV (Geo) unlike the positional nystagmus.

  9. Refractory Positional Vertigo With Apogeotropic Horizontal Nystagmus After Labyrinthitis: Surgical Treatment and Identification of Dysmorphic Ampullae.

    PubMed

    Ahmed, Sameer; Heidenreich, Katherine D; McHugh, Jonathan B; Altschuler, Richard A; Carender, Wendy J; Telian, Steven A

    2015-09-01

    To describe the rationale, intraoperative details, and histopathologic findings discovered when treating an unusual case of apogeotropic horizontal canal positional vertigo with a transmastoid labyrinthectomy. A single case report. Therapeutic. Resolution of apogeotropic nystagmus and improvement of positional vertigo. The apogeotropic variant of horizontal canal positional vertigo can be a difficult entity to treat. This report describes a patient who developed profound sensorineural hearing loss and vertigo after an acute left labyrinthitis. Ten months later, she developed vertigo with apogeotropic positional nystagmus involving the left horizontal semicircular canal. Particle repositioning maneuvers and vestibular physical therapy were unsuccessful. In addition, she developed intermittent positional vertigo affecting the ipsilateral vertical semicircular canals. Given the persistence of her vertigo, multiple canal involvement, and patient preference for definitive treatment, a transmastoid labyrinthectomy was performed. Intraoperatively, the ampulla of the horizontal canal as well as that of the other canals was grossly abnormal as later confirmed on histology. After surgery, her apogeotropic nystagmus and vertigo resolved, and her balance ability gradually improved to a highly functional level. This case illustrates a unique form of positional vertigo that developed and persisted after acute labyrinthitis. Conservative measures were unsuccessful and a transmastoid labyrinthectomy documented dense inflammatory tissue involving all three ampullae. We postulate that the post-labyrinthitic inflammatory changes resulted in mass loading of the membranous ampullae, causing abnormal nystagmus patterns and positional vertigo, which resolved after the labyrinthectomy.

  10. Human vestibular memory studied via measurement of the subjective horizontal during gondola centrifugation.

    PubMed

    Tribukait, Arne

    2003-07-01

    Measurements of the subjective visual horizontal (SVH) were made in a large swing-out gondola centrifuge. Rotation of the centrifuge was anti-clockwise, as seen from above. Test subjects were seated upright in the gondola, facing forwards. In front of the subject, at a straight-ahead eye-level position, there was a narrow luminous line, which could be rotated, by remote control, about the visual axis. At gravitoinertial force levels of 1.1-1.3G the subjects were asked to indicate, by repeatedly setting the line in darkness, what they perceived as horizontal (the SVH). During gondola centrifugation, the head and body length axis is always parallel with the resultant gravitoinertial force vector (vectorial sum of earth gravity force and the centrifugal force) i.e., the horizontal plane of the head or body does not change with respect to the gravitoinertial horizontal. Hence, the otolith organs, as well as the somatosensory system, continually signal upright position. However, the swing-out of the gondola during acceleration of the centrifuge (25 degrees at 1.1G) is a roll (frontal plane) change-in-position stimulus to the vertical semicircular canals, thus creating an otolith-semicircular canal conflict. After acceleration of the centrifuge, the SVH was initially tilted up to 20 degrees to the right relative to the gravitoinertial horizontal. Since there was no roll-tilt stimulus to gravity receptors, this SVH tilt must be related to stimulation of the semicircular canals. However, it decayed much more slowly than any known effects of angular-velocity stimulation of the semicircular canals. The decay was bi-phasic with two time constants, the smaller in the region of 1-2 min, the other being too large to be reliably estimated on the basis of data collected during only 10 min. This persistence of the SVH tilt suggests a memory for angular changes in roll head position detected by the semicircular canals-a position-storage mechanism. Further, the SVH seems to be

  11. The horizontal computerized rotational impulse test.

    PubMed

    Furman, Joseph M; Shirey, Ian; Roxberg, Jillyn; Kiderman, Alexander

    2016-01-01

    Whole-body impulsive rotations were used to overcome several limitations associated with manual head impulse testing. A computer-controlled rotational chair delivered brief, whole-body, earth-vertical axis yaw impulsive rotations while eye movements were measured using video-oculography. Results from an unselected group of 20 patients with dizziness and a group of 22 control subjects indicated that the horizontal computerized rotational head impulse test (crHIT) is well-tolerated and provides an estimate of unidirectional vestibulo-ocular reflex gain comparable to results from caloric testing. This study demonstrates that the horizontal crHIT is a new assessment tool that overcomes many of the limitations of manual head impulse testing and provides a reliable laboratory-based measure of unilateral horizontal semicircular canal function.

  12. Canal and otolith afferent activity underlying eye velocity responses to pitching while rotating.

    PubMed

    Raphan, T; Dai, M; Maruta, J; Waespe, W; Henn, V; Suzuki, J I; Cohen, B

    1999-05-28

    Pitching the head while rotating (PWR) combines periodic activation of the semicircular canals and the otoliths to generate pitch and roll eye deviations and continuous horizontal nystagmus. Monkeys were tested after individual pairs of semicircular canals were plugged and single units were recorded in the vestibular nerve while the animals were sinusoidally pitched 20-40 deg about a spatial horizontal axis with 5- and 16-s periods and simultaneously rotated about a spatial vertical axis at 30-120 deg/s. As previously shown, the steady-state horizontal response disappeared after plugging the vertical semicircular canals, but was maintained when the lateral canals were plugged. When the left anterior and right posterior canal (LARP) pair was left intact, the steady-state response depended on the axis about which the pitching took place. When the axis was normal to the LARP plane, there was no steady-state response. When the pitching axis was perpendicular to the LARP normal, the response was maximal. Firing rates of otolith units were approximately in phase with pitch position, and the addition of rotation about a vertical axis did not change the response. Lateral canal units did not have a steady-state modulation during pitch or constant velocity rotation. During PWR, they oscillated at twice the pitch frequency. This corresponded to the frequency at which the canal was maximally activated as it aligned with the plane of rotation. The amplitude of modulation increased proportionally to rotational velocity, but the phase remained the same. These characteristics were unchanged during roll while rotating (RWR), which induces little continuous nystagmus. Anterior and posterior canal units were maximally excited near pitch-velocity maxima and minima, respectively, during pure pitching. During PWR, however, the phases of both components simultaneously shifted toward each other and toward being in phase with otolith units. The peak excitation tended toward a forward

  13. The subjective horizontal in eccentric rotation influenced by peripheral vestibular lesion.

    PubMed

    Odkvist, L M; Gripmark, M A; Larsby, B; Ledin, T

    1996-03-01

    Peripheral vestibular equilibrium disorders may originate in various parts of the labyrinth or the vestibular nerve. Traditionally, the function of the lateral semicircular canals has been assessed with caloric irrigation, and sometimes falsely been interpreted as a vestibular nerve lesion. The vertical semicircular canals are not easily assessed. Caloric testing with the head in different positions is not very helpful, but the canals may pairwise be tested using specific rotational techniques. Often the otolithic organs, capable of detecting linear acceleration forces, are forgotten as a source of vertigo and dizziness. We have implemented horizontal rotatory testing with the subject seated eccentrically facing the direction of rotation as a means of assessing otolithic function. The subject experiences a lateral tilt and is instructed in darkness to put a short light bar in the position he thinks a water surface would have, which is identical to his perceived tilt. In 39 normal subjects, a theoretical tilt of 24 degrees was estimated as approximately 19.5 degrees, and the standard deviation was 6 degrees. A side difference index was proposed to be normal if below 25%. The preliminary findings in a few patients with known labyrinthine lesions are presented. We propose that otolithic as well as lateral semicircular canal functions are useful to monitor in patients with suspected peripheral equilibrium disorders.

  14. Canal switch and re-entry phenomenon in benign paroxysmal positional vertigo: difference between immediate and delayed occurrence.

    PubMed

    Dispenza, F; DE Stefano, A; Costantino, C; Rando, D; Giglione, M; Stagno, R; Bennici, E

    2015-04-01

    This prospective study was designed to evaluate the differences between immediate and delayed canal re-entry of otoliths after therapeutic manoeuvres in patients with benign paroxysmal positional vertigo (BPPV). A total of 196 patients with BPPV were visited and 127 matched our inclusion criteria. The mean age was 54.74 years. The horizontal semicircular canal (HSC) was involved in 30 cases and the posterior semicircular canal (PSC) in 97 patients. Patients with hearing loss in the ear affected by BPPV have a more recurrent form, compared to those with normal hearing. An immediate canal re-entry was recorded in 3 patients with HSC BPPV, all with geotropic nystagmus. In 7 patients with PSC BPPV, the immediate canal re-entry was detected and the delayed form was noted in 5 patients. The patients with the delayed canal re-entry underwent more than 2 previous manoeuvres. The canal re-entry was not related to the manoeuvre performed. The timing of the Dix-Hallpike test to verify the resolution of the BPPV had a significant role in immediate canal re-entry. A recurrence in the follow-up at least one month after treatment was recorded in 20 patients and was more frequent in patients that had canal re-entry. The canal re-entry or canal switch is a clinical entity that should be kept in mind of the neurotologist when approaching BPPV patients. It is important to distinguish it from recurrence when delayed and from manoeuvre failure when immediate. The timing of manoeuvre performing, in particular the final verification test after therapeutic sessions, is important to prevent the immediate reflux of particles into canals.

  15. Visual-vestibular interaction in humans during earth-horizontal axis rotation

    NASA Technical Reports Server (NTRS)

    Wall, Conrad, III; Furman, Joseph M. R.

    1990-01-01

    Visual-vestibular interaction using 60 percent constant velocity earth horizontal axis yaw rotation, simulating both the horizontal semicircular canals and the otolith organs, was measured in seven human subjects. Subjects were tested with their eyes open in the dark (EOD) while fixating upon a target rotating with them (FIX), and while observing stationary optokinetic stripes (VVR). Resulting nystagmus slow component velocity (SCV) was analyzed for EOD, FIX, and VVR conditions. It is concluded that the visual-vestibular interactions during EHA differ significantly from those during rotation about the vertical; specifically, there is a nonlinear interaction between linear acceleration and optokinetic nystagmus.

  16. Visual-vestibular interaction in humans during earth-horizontal axis rotation

    NASA Technical Reports Server (NTRS)

    Wall, Conrad, III; Furman, Joseph M. R.

    1990-01-01

    Visual-vestibular interaction using 60 percent constant velocity earth horizontal axis yaw rotation, simulating both the horizontal semicircular canals and the otolith organs, was measured in seven human subjects. Subjects were tested with their eyes open in the dark (EOD) while fixating upon a target rotating with them (FIX), and while observing stationary optokinetic stripes (VVR). Resulting nystagmus slow component velocity (SCV) was analyzed for EOD, FIX, and VVR conditions. It is concluded that the visual-vestibular interactions during EHA differ significantly from those during rotation about the vertical; specifically, there is a nonlinear interaction between linear acceleration and optokinetic nystagmus.

  17. Dynamics and kinematics of the angular vestibulo-ocular reflex in monkey: effects of canal plugging.

    PubMed

    Yakushin, S B; Raphan, T; Suzuki, J; Arai, Y; Cohen, B

    1998-12-01

    Dynamics and kinematics of the angular vestibulo-ocular reflex in monkey: effects of canal plugging. J. Neurophysiol. 80: 3077-3099, 1998. Horizontal and roll components of the angular vestibulo-ocular reflex (aVOR) were elicited by sinusoidal rotation at frequencies from 0.2 Hz (60 degrees/s) to 4.0 Hz ( approximately 6 degrees/s) in cynomolgus monkeys. Animals had both lateral canals plugged (VC, vertical canals intact), both lateral canals and one pair of the vertical canals plugged (RALP, right anterior and left posterior canals intact; LARP, left anterior and right posterior canal intact), or all six semicircular canal plugged (NC, no canals). In normal animals, horizontal and roll eye velocity was in phase with head velocity and peak horizontal and roll gains were approximately 0.8 and 0.6 in upright and 90 degrees pitch, respectively. NC animals had small aVOR gains at 0.2 Hz, and the temporal phases were shifted approximately 90 degrees toward acceleration. As the frequency increased to 4 Hz, aVOR temporal gains and phases tended to normalize. Findings were similar for the LARP, RALP, and VC animals when they were rotated in the planes of the plugged canals. That is, they tended to normalize at higher frequencies. A model was developed incorporating the geometric organization of the canals and first order canal-endolymph dynamics. Canal plugging was modeled as an alteration in the low frequency 3-db roll-off and corresponding dominant time constant. The shift in the low-frequency 3-dB roll-off was seen in the temporal responses as a phase lead of the aVOR toward acceleration at higher frequencies. The phase shifted toward stimulus velocity as the frequency increased toward 4.0 Hz. By incorporating a dynamic model of the canals into the three-dimensional canal system, the spatial responses were predicted at all frequencies. Animals were also stimulated with steps of velocity in planes parallel to the plugged lateral canals. This induced a response with a

  18. Two major cuticular proteins are required for assembly of horizontal laminae and vertical pore canals in rigid cuticle of Tribolium castaneum.

    PubMed

    Noh, Mi Young; Kramer, Karl J; Muthukrishnan, Subbaratnam; Kanost, Michael R; Beeman, Richard W; Arakane, Yasuyuki

    2014-10-01

    The insect exoskeleton is composed of cuticle primarily formed from structural cuticular proteins (CPs) and the polysaccharide chitin. Two CPs, TcCPR27 and TcCPR18, are major proteins present in the elytron (highly sclerotized and pigmented modified forewing) as well as the pronotum (dorsal sclerite of the prothorax) and ventral abdominal cuticle of the red flour beetle, Tribolium castaneum. Both CPs belong to the CPR family, which includes proteins that have an amino acid sequence motif known as the Rebers & Riddiford (R&R) consensus sequence. Injection of double-stranded RNA (dsRNA) for TcCPR27 and TcCPR18 resulted in insects with shorter, wrinkled, warped and less rigid elytra than those from control insects. To gain a more comprehensive understanding of the roles of CPs in cuticle assembly, we analyzed for the precise localization of TcCPR27 and the ultrastructural architecture of cuticle in TcCPR27- and TcCPR18-deficient elytra. Transmission electron microscopic analysis combined with immunodetection using gold-labeled secondary antibody revealed that TcCPR27 is present in dorsal elytral procuticle both in the horizontal laminae and in vertical pore canals. dsRNA-mediated RNA interference (RNAi) of TcCPR27 resulted in abnormal electron-lucent laminae and pore canals in elytra except for the boundary between these two structures in which electron-dense molecule(s) apparently accumulated. Insects subjected to RNAi for TcCPR18 also had disorganized laminae and pore canals in the procuticle of elytra. Similar ultrastructural defects were also observed in other body wall regions with rigid cuticle such as the thorax and legs of adult T. castaneum. TcCPR27 and TcCPR18 are required for proper formation of the horizontal chitinous laminae and vertical pore canals that are critical for formation and stabilization of rigid adult cuticle.

  19. Vertical eye movements during horizontal head impulse test: a new clinical sign of superior vestibular neuritis.

    PubMed

    D'Onofrio, F

    2013-12-01

    In some patients suffering from acute unilateral peripheral vestibular deficit, the head impulse test performed towards the affected side reveals the typical catch-up saccade in the horizontal plane, and an oblique, mostly vertical, upward catch-up saccade after the rotation of the head towards the healthy side. Three cases are reported herein, which have been studied using slow motion video analysis of the eye movements captured by a high-speed webcam (90 fps). The clinical evidence is discussed and a pathophysiological explanation is proposed, consisting in a selective hypofunction of the superior semicircular canal during superior vestibular neuritis.

  20. Earth horizontal axis rotational responses in patients with unilateral peripheral vestibular deficits

    NASA Technical Reports Server (NTRS)

    Furman, Joseph M. R.; Kamerer, Donald B.; Wall, Conrad, III

    1989-01-01

    The vestibulo-ocular reflex (VOR) of five patients with surgically confirmed unilateral peripheral vestibular lesions is evaluated. Testing used both earth vertical axis (EVA) and earth horizontal axis (EHA) yaw rotation. Results indicated that the patients had short VOR time constants, asymmetric responses to both EVA and EHA rotation, and normal EHA modulation components. These findings suggest that unilateral peripheral vestibular loss causes a shortened VOR time constant even with the addition of dynamic otolithic stimulation and causes an asymmetry in semicircular canal-ocular reflexes and one aspect of otolith-ocular reflexes.

  1. Earth horizontal axis rotational responses in patients with unilateral peripheral vestibular deficits

    NASA Technical Reports Server (NTRS)

    Furman, Joseph M. R.; Kamerer, Donald B.; Wall, Conrad, III

    1989-01-01

    The vestibulo-ocular reflex (VOR) of five patients with surgically confirmed unilateral peripheral vestibular lesions is evaluated. Testing used both earth vertical axis (EVA) and earth horizontal axis (EHA) yaw rotation. Results indicated that the patients had short VOR time constants, asymmetric responses to both EVA and EHA rotation, and normal EHA modulation components. These findings suggest that unilateral peripheral vestibular loss causes a shortened VOR time constant even with the addition of dynamic otolithic stimulation and causes an asymmetry in semicircular canal-ocular reflexes and one aspect of otolith-ocular reflexes.

  2. How could canal-pluggings result in intensive direction changing type of positional nystagmus?

    PubMed

    Arai, Y; Henn, V; Boehmer, A; Suzuki, J

    1989-01-01

    The objectives of this study in Rhesus monkeys is to observe the sequences which appear in the oculo-spinal-motor system after selected semicircular canals had been plugged. The left anterior and the right posterior canals in a monkey "LARP", the left anterior and posterior canals in "LALP", and the left lateral canal in "LL" were plugged under intubation general anesthesia. Three-dimensional eye recordings were performed, using two scleral coils. Behavior, posture, and vestibulo-ocular reflex were studied. Compensation was established in the light within 2 days. In darkness, no spontaneous nystagmus was recorded in the sitting position. The monkey "LALP" developed marked positional nystagmus. When the head position was changed up to 360 degrees in 15 degrees steps, horizontal, vertical and torsional eye movements showed remarkable changes. Spontaneous direction changing nystagmus in darkness was also recorded in "LALP". To conclude, direction changing positional nystagmus, which was seen for several months after the canal plugging, was difficult to explain by the damage to the adjacent ampullary and/or otolithic endorgans, but may be explained by the limited otolithic compensation in the earth parallel plane for the defective dynamic canal inputs. These observations and conclusions were from experiments using three monkeys only and should still be confirmed in more extended experiments.

  3. Direction-fixed paroxysmal nystagmus lateral canal benign paroxysmal positioning vertigo (BPPV): another form of lateral canalolithiasis.

    PubMed

    Califano, L; Vassallo, A; Melillo, M G; Mazzone, S; Salafia, F

    2013-08-01

    Benign paroxysmal positioning vertigo (BPPV) is the most frequent vertiginous syndrome. It is caused either by free-floating otoliths in the semicircular canals (canalolithiasis) or by otoconial debris adhering to a canal cupula (cupulolithiasis). The posterior canal is the most frequently involved (80%), while the lateral canal is involved less frequently (15%), and the rarest conditions are anterior canalolithiasis and apogeotropic posterior canalolithiasis (5%). The main diagnostic sign of lateral canal BPPV is paroxysmal horizontal bidirectional positioning nystagmus evoked through Pagnini-McClure's test (head roll in the yaw plane in supine position). In the geotropic variant, which is more frequent, the fast phase of the nystagmus is directed towards the lowermost ear, when the patient lies on the affected side or on the healthy side; in the apogeotropic variant, which is less frequent, the fast phase is directed always toward the uppermost ear, regardless of which side the patient lies on. Paroxysmal nystagmus is more intense on the affected side in the geotropic form, and more intense on the healthy side in the apogeotropic form. The authors describe five cases of another primitive and rare form of lateral BPPV, defined as "direction-fixed paroxysmal nystagmus lateral canal BPPV", which has previously been described by other authors as a transitory step observed during the transformation from an apogeotropic into a geotropic form. It is characterized by typical BPPV symptoms and diagnosed by the presence of a paroxysmal horizontal unidirectional positioning nystagmus, evoked through Pagnini-McClure's test, which is apogeotropic on the affected side and geotropic on the healthy side. In the reported cases, direction-fixed horizontal paroxysmal nystagmus was always transformed into a typical geotropic form. The clinical features and pathophysiology of direction-fixed nystagmus lateral canal BPPV are discussed.

  4. Canal and otolith vestibulo-ocular reflexes to vertical and off vertical axis rotations in children learning to walk.

    PubMed

    Wiener-Vacher, S R; Toupet, F; Narcy, P

    1996-09-01

    In order to determine the characteristics of the vestibulo-ocular reflexes (VORs) as a function of age and posturo-motor development, a group of 26 normal children (6 to 25 months old) were tested at three different stages of posturo-motor control: prior to as well as during the first attempts to walk without support, and during the first year of independent walking. The test consisted of electro-oculographic (EOG) recordings of the VOR responses to horizontal semi-circular canal and otolith stimulations. The canal VOR was elicited in seated subjects by rotatory impulsions about a vertical axis (acceleration and deceleration both at 40 degrees/s2, separated by a rotation at 60 degrees/s velocity). The otolith VOR was elicited by inclining the rotating chair by 9 degrees respect to gravity. For the canal VOR, the time constant and the highest initial slow phase velocity were measured. The otolith VOR was characterized by the amplitude of the modulation and the bias (offset of baseline from zero) of the slow phase velocity averaged over 10 to 20 rotation cycles, for both the horizontal and vertical components of the response. The pooled values of these data show that canal VOR parameters did not vary significantly either with age of the children or with their stage of posturo-motor control. However, the otolith VOR parameters changed during the period of learning to walk: the modulation of the horizontal component increased and the modulation of the vertical component decreased significantly. Thus the ability to walk without support is marked by a significant change in the otolith but not canal responses; since the vestibular sensory organs develop anatomically at the same rate these results indicate that central nervous system processors of canal and otolith information develop independently.

  5. Micromotional studies of utricular and canal afferents

    NASA Technical Reports Server (NTRS)

    Lewis, Edwin R.

    1989-01-01

    The long-range goal of this research was to refine our understanding of the sensitivity of the vestibular components of the ear to very-low-amplitude motion, especially, the role of gravity in this sensitivity. We focused on the American bullfrog--a common animal subject for vestibular sensory research. Our principal experimental method was to apply precise, sinusoidal microrotational stimuli to an anesthetized animal subject, to record the resulting responses in an individual vestibular nerve fiber from the intact ear, and to use intracellular dye to trace the fiber and thus identify the vestibular sensor that gave rise to it. In this way, we were able to identify specific micromotional sensitivities and to associate those sensitivities definitely with specific sensors. Furthermore, by recording from nerve fibers after they leave the intact inner-ear cavity, we were able to achieve these identifications without interrupting the delicate micromechanics of the inner ear. We were especially concerned with the relative roles of the utricle and the anterior semicircular canal in the sensing of microrotational motion of the head about horizontal axes, and with the role of gravity in mediating that sensing process in the utricle. The functional characterization of individual nerve fibers was accomplished with a conventional analytical tool, the cycle histogram, in which the nerve impulse rate was plotted against the phase of the sinusoidal stimulus.

  6. Skull vibration-induced nystagmus test in unilateral superior canal dehiscence and otosclerosis: a vestibular Weber test.

    PubMed

    Dumas, Georges; Lion, Alexis; Karkas, Alexandre; Perrin, Philippe; Perottino, Flavio; Schmerber, Sébastien

    2014-06-01

    The skull vibration-induced nystagmus test (SVINT) acts as a vestibular Weber test and reveals a vibration-induced nystagmus (VIN), elicited mainly on the vertex location, with a horizontal or torsional component beating more often toward the side of the lesion in superior canal dehiscence (SCD) than in otosclerosis (OS). In SCD, the VIN vertical component is most often up-beating. These results suggest more a global vestibular contribution than the sole stimulation of the superior semicircular canal. This study aimed to evaluate the possible occurrence of nystagmus during SVINT in unilateral conductive hearing loss related to SCD or OS. The slow-phase velocities (SPVs) of the VIN horizontal, torsional, and vertical components were recorded in patients with a unilateral otologic lesion (17 SCD, 38 OS) and 12 control subjects. Vibratory stimulations (60 Hz, 100 Hz) were applied on the vertex and on each mastoid. In SCD, VIN was observed in 82% of patients with a primarily torsional, horizontal, and vertical (up-beating) component in 40%, 30%, and 30%, respectively. Horizontal and torsional components beat toward the side of the lesion more often than in OS. Higher SPVs were observed after vertex stimulation. In OS, VIN was sparse with low amplitude and was not systematically lateralized to a specific side.

  7. Canal plane dynamic visual acuity in superior canal dehiscence.

    PubMed

    Janky, Kristen L; Zuniga, M Geraldine; Ward, Bryan; Carey, John P; Schubert, Michael C

    2014-06-01

    1) To characterize normal, horizontal active dynamic visual acuity (DVA) and passive canal plane head thrust DVA (htDVA) across ages to establish appropriate control data and 2) to determine whether horizontal active DVA and passive canal plane htDVA are significantly different in individuals with superior canal dehiscence syndrome (SCDS) before and after surgical repair in the acute (within 10 d) and nonacute stage (>6 wk). Prospective study. Tertiary referral center Patients diagnosed with SCDS (n = 32) and healthy control subjects (n = 51). Surgical canal plugging on a subset of patients. Static visual acuity (SVA), active horizontal DVA, and canal plane htDVA. Visual acuity (SVA, active DVA, and htDVA) declines with age. In SCDS, SVA and active DVA are not significantly affected in individuals after surgical canal plugging; however, htDVA in the plane of the affected canal is significantly worse after canal plugging. Age-based normative data are necessary for DVA testing. In SCDS, htDVA in the plane of the affected canal is normal before surgery but permanently reduced afterward.

  8. Spin-up in a semicircular cylinder

    NASA Astrophysics Data System (ADS)

    Andersson, H. I.; Billdal, J. T.; van Heijst, G. J. F.

    1992-09-01

    The spin-up from rest of a free-surface fluid in a cylindrical container of semicircular cross section is investigated using a time-dependent 3D numerical simulation. The numerical simulation provides information about the secondary meridional flow, the bottom Eckman layer, and the changing spatial velocity distribution of the flow field. The numerical results are found to be in good agreement with laboratory observations.

  9. Delamination stresses in semicircular laminated composite bars

    NASA Technical Reports Server (NTRS)

    Ko, William L.

    1988-01-01

    Using anisotropic elasticity theory, delamination stresses in a semicircular laminated composite curved bar subjected to end forces and end moments were calculated, and their radial locations determined. A family of design curves was presented, showing variation of the intensity of delamination stresses and their radial locations with different geometry and different degrees of anisotropy of the curved bar. The effect of anisotropy on the location of peak delamination stress was found to be small.

  10. User manual for semi-circular compact range reflector code: Version 2

    NASA Technical Reports Server (NTRS)

    Gupta, Inder J.; Burnside, Walter D.

    1987-01-01

    A computer code has been developed at the Ohio State University ElectroScience Laboratory to analyze a semi-circular paraboloidal reflector with or without a rolled edge at the top and a skirt at the bottom. The code can be used to compute the total near field of the reflector or its individual components at a given distance from the center of the paraboloid. The code computes the fields along a radial, horizontal, vertical or axial cut at that distance. Thus, it is very effective in computing the size of the sweet spot for a semi-circular compact range reflector. This report describes the operation of the code. Various input and output statements are explained. Some results obtained using the computer code are presented to illustrate the code's capability as well as being samples of input/output sets.

  11. Dynamic Visual Acuity during Passive Head Thrusts in Canal Planes

    PubMed Central

    Migliaccio, Americo A.; Della Santina, Charles C.

    2006-01-01

    We sought to determine whether the dynamic visual acuity (DVA) test, which has been used to measure the function of the two horizontal semicircular canals (SCCs), could be adapted to measure the individual function of all six SCCs using transient, rapid, unpredictable head rotation stimuli (head thrusts) in the direction of maximum sensitivity of each SCC. We examined head-thrust DVA (htDVA) performance in 19 healthy control subjects, five patients before and six patients after plugging of one superior SCC for treatment of superior canal dehiscence, and two subjects with unilateral vestibular deafferentation (UVD) by vestibular neurectomy. We compared htDVA results for each SCC to vestibulo-ocular reflex gains measured using 3-D scleral coil recordings during a passive head-thrust-test paradigm. Individuals with normal vestibular function had similar htDVA scores for each of the six directions (canals) tested (mean 0.058 ± 0.050 LogMAR). Individuals tested after surgical plugging of one superior SCC were similar to normal for all SCCs except the plugged SCC, which had significantly worse htDVA scores (mean 0.270 ± 0.08 LogMAR). Individuals with UVD had significantly worse htDVA scores for head rotations maximally exciting any of the ipsilesional SCC (mean 0.317 ± 0.129 LogMAR) and scores similar to normal subjects for contralesional rotations (0.063 ± 0.051 LogMAR). These findings suggest that the htDVA test, which does not require scleral coil placement, magnetic field coils, or expensive oculography equipment, can provide a useful quantitative measure of individual SCC function. PMID:16810569

  12. Physiological mechanisms of the nystagmus produced by rotations about an earth-horizontal axis

    NASA Technical Reports Server (NTRS)

    Goldberg, J. M.; Fernandez, C.

    1981-01-01

    The physiological basis of the nystagmus produced by rotation about an earth-horizontal axis is investigated with particular emphasis on the unidirectional nystagmus attributed to a bias component. Eye movement recordings were made with dc electro-oculography in alert squirrel monkeys and afferent responses were recorded from semicircular canals and otolith receptors of anesthetized animals upon rotations in the pitch and yaw planes. The eye-movement recordings show the rotation responses in the squirrel monkey to resemble those of other species, including persistent horizontal and vertical nystagmuses during yaw and pitch rotations, respectively, a unidirectional nystagmus at low rotation speeds, and postrotatory responses of relatively small amplitude and duration. The vestibular nerve recordings do not show a directionally specific dc response that can account for the bias component, but instead exhibit sinusoidal responses of peak amplitudes 0-15 and 25-75 spikes/sec for the canals and otolith, respectively. Results thus indicate that the dc signal to the oculomotor centers responsible for the nystagmus is of central origin, most likely based on some transformation of the otolith signals.

  13. Physiological mechanisms of the nystagmus produced by rotations about an earth-horizontal axis

    NASA Technical Reports Server (NTRS)

    Goldberg, J. M.; Fernandez, C.

    1981-01-01

    The physiological basis of the nystagmus produced by rotation about an earth-horizontal axis is investigated with particular emphasis on the unidirectional nystagmus attributed to a bias component. Eye movement recordings were made with dc electro-oculography in alert squirrel monkeys and afferent responses were recorded from semicircular canals and otolith receptors of anesthetized animals upon rotations in the pitch and yaw planes. The eye-movement recordings show the rotation responses in the squirrel monkey to resemble those of other species, including persistent horizontal and vertical nystagmuses during yaw and pitch rotations, respectively, a unidirectional nystagmus at low rotation speeds, and postrotatory responses of relatively small amplitude and duration. The vestibular nerve recordings do not show a directionally specific dc response that can account for the bias component, but instead exhibit sinusoidal responses of peak amplitudes 0-15 and 25-75 spikes/sec for the canals and otolith, respectively. Results thus indicate that the dc signal to the oculomotor centers responsible for the nystagmus is of central origin, most likely based on some transformation of the otolith signals.

  14. Canal-otolith interactions and detection thresholds of linear and angular components during curved-path self-motion.

    PubMed

    MacNeilage, Paul R; Turner, Amanda H; Angelaki, Dora E

    2010-08-01

    Gravitational signals arising from the otolith organs and vertical plane rotational signals arising from the semicircular canals interact extensively for accurate estimation of tilt and inertial acceleration. Here we used a classical signal detection paradigm to examine perceptual interactions between otolith and horizontal semicircular canal signals during simultaneous rotation and translation on a curved path. In a rotation detection experiment, blindfolded subjects were asked to detect the presence of angular motion in blocks where half of the trials were pure nasooccipital translation and half were simultaneous translation and yaw rotation (curved-path motion). In separate, translation detection experiments, subjects were also asked to detect either the presence or the absence of nasooccipital linear motion in blocks, in which half of the trials were pure yaw rotation and half were curved path. Rotation thresholds increased slightly, but not significantly, with concurrent linear velocity magnitude. Yaw rotation detection threshold, averaged across all conditions, was 1.45 +/- 0.81 degrees/s (3.49 +/- 1.95 degrees/s(2)). Translation thresholds, on the other hand, increased significantly with increasing magnitude of concurrent angular velocity. Absolute nasooccipital translation detection threshold, averaged across all conditions, was 2.93 +/- 2.10 cm/s (7.07 +/- 5.05 cm/s(2)). These findings suggest that conscious perception might not have independent access to separate estimates of linear and angular movement parameters during curved-path motion. Estimates of linear (and perhaps angular) components might instead rely on integrated information from canals and otoliths. Such interaction may underlie previously reported perceptual errors during curved-path motion and may originate from mechanisms that are specialized for tilt-translation processing during vertical plane rotation.

  15. Changes in the perceived head transversal plane and the subjective visual horizontal induced by Coriolis stimulation during gondola centrifugation.

    PubMed

    Tribukait, Arne; Eiken, Ola

    2006-01-01

    For studying the influence of the vertical semicircular canals on spatial orientation in roll, the subjective visual horizontal (SVH) and the subjective transversal plane of the head (STP) were measured in a situation where the vertical canals sense a roll-velocity stimulus while the otolith organs persistently signal that the head is upright in roll. During gondola centrifugation (resultant gravitoinertial force vector 2.5 G, gondola inclination 66 degrees) subjects were exposed to controlled rotational head movements (angular speed 27 degrees/s, magnitude 40 degrees) about the yaw (body z-) axis, produced by means of a motor-driven helmet. This causes a roll-plane Coriolis stimulus to the canals, while the otoliths persistently sense upright head position in roll. The subjects reported intense sensations of rotation and tilt in the roll plane. This was reflected in tilts of both the SVH and STP. The initial tilt of the SVH was 13.0 +/- 9.7 degrees (mean +/- S.D., n=10). The STP was changed in the opposite direction. The initial tilt was 23.8 +/- 12.2 degrees (mean +/- S.D., n=5). The changes in the SVH and STP were not of equal magnitude. A few subjects who had almost no deviations in the SVH showed pronounced tilts of the STP. The time constant for exponential decay of the tilts of the SVH and STP was on average approximately 1 minute. These findings indicate that a difference in activity of the vertical canals in the right versus left ear may cause substantial tilts of the SVH even if there is no asymmetry in the activity of the otolith system. Further, the canal stimulus may induce a tilt of the fundamental egocentric frame of reference.

  16. Incidence of accessory canals in Japanese anterior maxillary teeth following root canal filling ex vivo.

    PubMed

    Adorno, C G; Yoshioka, T; Suda, H

    2010-05-01

    To investigate the vertical and horizontal distribution and the incidence of accessory canals in Japanese maxillary anterior teeth following root filling. The study included maxillary teeth; 69 central incisors, 61 lateral incisors and 31 canines. After the canal systems had been dyed and root canal instrumentation had been carried out, all prepared canals were filled with gutta-percha without using sealer. Transparent specimens were then obtained and examined with a digital microscope for horizontal and vertical distributions of accessory canals. The incidence of teeth with accessory canals in the apical 3 mm was 46%, 29% and 38% for the maxillary central incisors, lateral incisors and canines, respectively. The horizontal distribution was mainly buccal for central incisors, palatal for lateral incisors and distal and palatal for canines. There was a significant difference (P < 0.05) between the apical 3 mm and the rest of the root (16%, 20% and 19% for the maxillary central incisors, lateral incisors and canines, respectively) in terms of the presence of accessory canals. A high percentage of accessory canals can be found in apical 3 mm of the root. The horizontal distribution of accessory canals differed amongst the tooth types studied.

  17. Theoretical considerations on canal-otolith interaction and an observer model.

    PubMed

    Bos, Jelte E; Bles, Willem

    2002-03-01

    Subjective vertical orientation, eye and body movements, and motion sickness all depend on the way our central nervous system deals with the gravito-inertial force resolution problem: how to discern accelerations due to motion from those due to gravity, despite these accelerations being physically indistinguishable. To control body or eye movements, the accelerations due to motion should be known explicitly. Hence, somehow gravity should be filtered out of the specific force or gravito-inertial acceleration (GIA, the sum of both accelerations) as sensed by the otoliths, which are the linear accelerometers in the inner ear. As the GIA also changes in a head-fixed frame of reference when the head is rotated, angular motion as sensed by the semicircular canals in the inner ear should also be considered. We present here a theoretical approach to this problem, and show that the mathematical description of canal-otolith interaction is in fact a three-dimensional equivalent of the two-dimensional description given by Mayne in 1974. A simple low-pass filter is used to divide the GIA into a motion and a gravity component. The retardation of the somatogravic effect by concomitant angular motion during centrifugation is shown as a result. Furthermore we show how the canal-otolith interaction fits within the framework of an observer model to describe subjective vertical orientation, eye movement and motion sickness characteristics. To predict a frequency peak in sickness severity, for example, it is necessary to explicitly include the Mayne equation operating both on sensor afferents and in the internal model. From tilt and translation data from centrifugation and horizontal oscillation, as well as from motion sickness data, we conclude that the time constant of the low-pass filter is in the order of seconds instead of tens of seconds as assumed before. Several corollaries are additionally discussed as a result.

  18. Superior canal dehiscence size: multivariate assessment of clinical impact.

    PubMed

    Chien, Wade W; Janky, Kristen; Minor, Lloyd B; Carey, John P

    2012-07-01

    To examine the association between dehiscence length in patients with superior semicircular canal dehiscence syndrome and their clinical findings, including objective audiometric and vestibular testing results. Retrospective study. Tertiary referral center. Patients included in this study were diagnosed with superior semicircular canal dehiscence syndrome and underwent surgical repair of the dehiscence through middle fossa craniotomy. The dehiscence length was measured intraoperatively in all cases. Correlation between dehiscence length with pure-tone average (PTA), average bone-conduction threshold, maximal air-bone gap, cervical vestibular evoked myogenic potential thresholds, and presenting signs and symptoms. The correlation between dehiscence length and maximal air-bone gap was statistically significant on both univariate and multivariate regression analyses. The correlations between dehiscence length and PTA, average bone-conduction threshold, cervical vestibular evoked myogenic potential threshold, and presenting signs and symptoms were not statistically significant. The dehiscence length correlated positively with the maximal air-bone gap in patients with superior semicircular canal dehiscence. The correlation was statistically significant. The dehiscence length did not correlate with the other variables examined in this study.

  19. Superior canal dehiscence: mechanisms of pressure sensitivity in a chinchilla model.

    PubMed

    Hirvonen, T P; Carey, J P; Liang, C J; Minor, L B

    2001-11-01

    Patients with superior canal dehiscence syndrome may experience vertigo and nystagmus when pressure changes occur in the external auditory canal, the middle ear, or the intracranial space. The cause is a defect in the bone of the superior canal. To study the mechanisms of pressure sensitivity of the labyrinth in superior canal dehiscence syndrome and its surgical repair in a chinchilla model. We investigated the changes in firing rates of vestibular nerve afferents in the chinchilla in response to changes in external auditory canal pressure before and after fenestration of the superior canal, and after repair of the fenestra. Before superior canal fenestration, external auditory canal pressure changes caused no responses in horizontal canal or otolith afferents, and only 1 of 9 superior canal afferents responded to pressure. After fenestration, all superior canal afferents were excited by positive pressure and inhibited by negative pressure. Half of 18 otolith and most (21 of 33) horizontal canal afferents were unaffected by pressure. The superior canal afferents had higher pressure gain than the horizontal canal afferents (P =.03). Pressure responses could be abolished only by applying a rigid seal to the fenestra. Fenestration of the superior canal rendered all superior canal afferents sensitive to pressure, whereas less than half of the other afferents became pressure sensitive. The direction of the superior canal afferent responses agreed with the predictions of our model of endolymph flow within the superior canal. A rigid seal applied to the fenestra abolished pressure sensitivity while maintaining physiologic rotational sensitivity.

  20. [Frequency characteristics of the semicicular canals damage in patients with Meniere disease].

    PubMed

    Xu, K X; Chen, T S; Wang, W; Li, S S; Liu, Q; Wen, C; Han, X; Lin, P

    2017-03-07

    Objective: To evaluate semicircular canal damage and its frequency characteristics in Meniere disease patients. Methods: Sixty-seven Meniere disease patients accepted the video-head impulse test(vHIT)which responses to semicircular canal function of high frequency area, head shaking test(HST) which responses to semicircular canal function of middle frequency area, and caloric test(CT) which responses to semicircular canal function of low frequency area.Preferences were recorded including the video head impulse test gain (vHIT-G), head shaking nystagmus (HSN) and parameters of the unilateral weakness (UW) as observation index, and results of all the three tests were analyzed according to Meniere disease patients. SPSS 17.0 software was used to analyzed the data. Results: The positive rate of CT, HSN and vHIT were 70.1%(47/67), 41.8%(28/67) and 23.9%(16/67) respectively. Comparation of the positive rate among CT, HST and vHIT showed statistically significant difference (χ(2)=10.93, P=0.001; χ(2)=28.79, P=0.000). Comparation of the positive rate between HST and vHIT showed statistically significant difference(χ(2)=4.87, P=0.027). Conclusions: Semicircular canal function damage in Meniere disease patients mainly presents in the low frequency area, which indicates a characteristic phenomenon that low-frequency function area (caloric test results) is more predisposed to be involved than that of middle-frequency function area (head shaking testing)and high-frequency function area (video head impulse testing) in Meniere disease patients.

  1. Ground motions around a semi-circular valley partially filled with an inclined alluvial layer under SH-polarized excitation

    NASA Astrophysics Data System (ADS)

    Chang, Kao-Hao; Tsaur, Deng-How; Wang, Jeen-Hwa

    2014-12-01

    A simplified mathematical model, composed of a semi-circular valley partially filled with an inclined alluvial layer under plane SH-wave incidence, is presented. To evaluate the site response theoretically, a rigorous series solution is derived via the region-matching technique. For angular wavefunctions constrained by an inclined free surface, the original form of Graf's addition formula is recast to arbitrarily shift the local coordinate system. The valley geometry, filling material, angle of incidence, and wave frequency are taken as significant parameters in exploring the site effect on ground motions. Also included are the frequency- and time-domain computations. Two canonical cases, the semi-circular vacant canyon and the fully filled semi-circular alluvial valley, with exact analytical solutions, and the partly horizontally filled case previously studied, are taken to be particular cases of the proposed general model. Steady-state results show that the peak amplitudes of motion may increase at low frequencies when the filling layer inclines to the illuminated region. At low-grazing incidence, the phenomenon of wave focusing becomes evident on the shadow side of the filling layer. Transient-state simulations elucidate how a sequence of surface waves travel on the topmost alluvium along opposite directions and interfere with multiple reflected waves within the filling layer.

  2. A linear canal-otolith interaction model to describe the human vestibulo-ocular reflex.

    PubMed

    Crane, B T; Demer, J L

    1999-08-01

    A control systems model of the vestibulo-ocular reflex (VOR) originally derived for yaw rotation about an eccentric axis (Crane et al. 1997) was applied to data collected during ambulation and dynamic posturography. The model incorporates a linear summation of an otolith response due to head translation scaled by target distance, adding to a semi-circular canal response that depends only on angular head rotation. The results of the model were compared with human experimental data by supplying head angular velocity as determined by magnetic search coil recording as the input for the canal branch of the model and supplying linear acceleration as determined by flux gate magnetometer measurements of otolith position. The model was fit to data by determining otolith weighting that enabled the model to best fit the data. We fit to the model experimental data from normal subjects who were: standing quietly, walking, running, or making active sinusoidal head movements. We also fit data obtained during dynamic posturography tasks of: standing on a platform sliding in a horizontal plane at 0.2 Hz, standing directly on a platform tilting at 0.1 Hz, and standing on the tilting platform buffered by a 5-cm thick foam rubber cushion. Each task was done with the subject attending a target approximately 500, 100, or 50 cm distant, both in light and darkness. The model accurately predicted the observed VOR response during each test. Greater otolith weighting was required for near targets for nearly all activities, consistent with weights for the otolith component found in previous studies employing imposed rotations. The only exceptions were for vertical axis motion during standing, sliding, and tilting when the platform was buffered with foam rubber. In the horizontal axis, the model always fit near target data better with a higher otolith component. Otolith weights were similar with the target visible and in darkness. The model predicts eye movement during both passive whole

  3. Rear semicircular section of the highlift pumping station basement with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Rear semi-circular section of the high-lift pumping station basement with remnants of the piping systems and suction wells at rear wall. - Robert B. Morse Water Filtration Plant, 10700 and 10701 Columbia Pike, Silver Spring, Montgomery County, MD

  4. 21. REAR OF OLD FAITHFUL INN, LOOKING NORTH. SEMICIRCULAR SIDE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. REAR OF OLD FAITHFUL INN, LOOKING NORTH. SEMI-CIRCULAR SIDE DINING ROOM, NOW CALLED THE BEAR PIT WAS ADDED IN 1927. (TAKEN FROM CHERRY-PICKER) - Old Faithful Inn, 900' northeast of Snowlodge & 1050' west of Old Faithful Lodge, Lake, Teton County, WY

  5. Galvanic vestibular stimulation combines with Earth-horizontal rotation in roll to induce the illusion of translation.

    PubMed

    Schneider, Erich; Bartl, Klaus; Glasauer, Stefan

    2009-05-01

    Human head rotation in roll around an earth-horizontal axis constitutes a vestibular stimulus that, by its rotational component, acts on the semicircular canals (SCC) and that, by its tilt of the gravity vector, also acts on the otoliths. Galvanic vestibular stimulation (GVS) is thought to resemble mainly a rotation in roll. A superposition of sinusoidal GVS with a natural earth-horizontal roll movement was therefore applied in order to cancel the rotation effects and to isolate the otolith activation. By self-adjusting the amplitude and phase of GVS, subjects were able to minimize their sensation of rotation and to generate the perception of a linear translation. The final adjustments are in the range of a model that predicts SCC activation during natural rotations and GVS. This indicates that the tilt-translation ambiguity of the otoliths is resolved by SCC-otolith interaction. It is concluded that GVS might be able to cancel rotations in roll and that the residual tilt of the gravitoinertial force is possibly interpreted as a linear translation.

  6. Morphological change of the cupula due to an ototoxic agent: a comparison with semicircular canal pathology.

    PubMed

    Konomi, Ujimoto; Suzuki, Mamoru; Otsuka, Koji; Shimizu, Akira; Inagaki, Taro; Hasegawa, Go; Shimizu, Shigetaka; Motohashi, Rei

    2010-06-01

    The cupula shows various degrees of changes after gentamicin (GM) injection into the inner ear, with or without damage of the sensory cells. This cupula change may be a part of the etiology of peripheral vertigo, and is also potentially one of the mechanisms of reduced caloric response. To observe the morphological changes of the cupula after injecting GM in the frog inner ear and to compare the changes of the cupula with those of the ampullary sensory cells. We injected 300 microg (7.5 microl) of GM into the inner ear of 30 bullfrogs (Rana catesbeiana) using a microsyringe under ether anesthesia. The same amount of saline was injected into the other ear as control. The cupulae were observed at 3, 7, and 14 days after GM injection by stereoscopic microscope. The ampullae were fixed, and the sensory cells were assessed using a scanning electron microscope (SEM). The correlation between the changes in the cupula and sensory cells was evaluated using our own scale. In over half of the cupulae in the 7- and 14-day groups, cupula changes such as shrinkage were observed. In about 50% of the total cases, the degree of cupula and sensory cell change correlated in the two groups. In the 14-day group, these changes were more marked. However, there were cases in which the changes of the cupula and sensory cells did not correlate, indicating that the cupula alone can sustain changes without sensory cell damage.

  7. The relative roles of the otolith organs and semicircular canals in producing space motion sickness

    NASA Technical Reports Server (NTRS)

    Parker, D. E.

    1998-01-01

    Inflight and post-landing "immunity" to the "coriolis sickness susceptibility test", observed during the Skylab M131 experiment, suggests that the otolith organs play a major role in space motion sickness (SMS). This view is supported by the report that ocular counter-torsion asymmetries correlate with SMS incidence and severity. Further data indicate that sensory-motor adaptation to microgravity includes a process whereby central interpretation of otolith signals is biased from "tilt" toward translation. However, unexpected responses to linear acceleration suggest the importance of graviceptors distributed throughout the body in addition to the vestibular otolith organs. Research is needed to assess distributed graviceptor effects.

  8. Design and performance of a multichannel vestibular prosthesis that restores semicircular canal sensation in rhesus monkey

    PubMed Central

    Chiang, Bryce; Fridman, Gene Y.; Dai, Chenkai; Rahman, Mehdi A.; Della Santina, Charles C.

    2012-01-01

    In normal individuals, the vestibular labyrinths sense head movement and mediate reflexes that maintain stable gaze and posture. Bilateral loss of vestibular sensation causes chronic disequilibrium, oscillopsia, and postural instability. We describe a new multichannel vestibular prosthesis (MVP) intended to restore modulation of vestibular nerve activity with head rotation. The device comprises motion sensors to measure rotation and gravitoinertial acceleration, a microcontroller to calculate pulse timing, and stimulator units that deliver constant-current pulses to microelectrodes implanted in the labyrinth. This new MVP incorporates many improvements over previous prototypes, including a 50% decrease in implant size, a 50% decrease in power consumption, a new microelectrode array design meant to simplify implantation and reliably achieve selective nerve-electrode coupling, multiple current sources conferring ability to simultaneously stimulate on multiple electrodes, and circuitry for in vivo measurement of electrode impedances. We demonstrate the performance of this device through in vitro bench-top characterization and in vivo physiological experiments with a rhesus macaque monkey. PMID:21859631

  9. Design and performance of a multichannel vestibular prosthesis that restores semicircular canal sensation in rhesus monkey.

    PubMed

    Chiang, Bryce; Fridman, Gene Y; Dai, Chenkai; Rahman, Mehdi A; Della Santina, Charles C

    2011-10-01

    In normal individuals, the vestibular labyrinths sense head movement and mediate reflexes that maintain stable gaze and posture. Bilateral loss of vestibular sensation causes chronic disequilibrium, oscillopsia, and postural instability. We describe a new multichannel vestibular prosthesis (MVP) intended to restore modulation of vestibular nerve activity with head rotation. The device comprises motion sensors to measure rotation and gravitoinertial acceleration, a microcontroller to calculate pulse timing, and stimulator units that deliver constant-current pulses to microelectrodes implanted in the labyrinth. This new MVP incorporates many improvements over previous prototypes, including a 50% decrease in implant size, a 50% decrease in power consumption, a new microelectrode array design meant to simplify implantation and reliably achieve selective nerve-electrode coupling, multiple current sources conferring ability to simultaneously stimulate on multiple electrodes, and circuitry for in vivo measurement of electrode impedances. We demonstrate the performance of this device through in vitro bench-top characterization and in vivo physiological experiments with a rhesus macaque monkey.

  10. 11. REMNANTS OF FLUME BOX WITHIN CANAL. NOTE THE UPRIGHT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. REMNANTS OF FLUME BOX WITHIN CANAL. NOTE THE UPRIGHT SIDE POSTS BOLTED TO BASE STRINGER AND HORIZONTAL BOARD SIDE WALLS. VIEW IS TO THE SOUTHEAST. - Snake River Ditch, Headgate on north bank of Snake River, Dillon, Summit County, CO

  11. 68. CANAL PLAN 5 EAST. CANAL BED IS VISIBLE WHILE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    68. CANAL PLAN 5 EAST. CANAL BED IS VISIBLE WHILE FOOT OF CANAL IS UNDERGOING MAINTAINANCE. NOTE HOW LARGE AMOUNTS OF DIRT ARE HAULED FROM PLACE TO PLACE USING A CANAL BOAT AND CRADLE. - Morris Canal, Phillipsburg, Warren County, NJ

  12. 3. ELEVATION. FROM SOUTH WITH CANAL PRISM. Canal Road ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. ELEVATION. FROM SOUTH WITH CANAL PRISM. - Canal Road Bridge, Canal Road spanning Delaware Canal Diversion, Locks 22 & 23 in Delaware Canal State Park in Williams Township, Raubsville, Northampton County, PA

  13. Surgical management of 2 different presentations of ear canal atresia in dogs.

    PubMed

    Béraud, Romain

    2012-04-01

    A 6-year-old French spaniel and a 14-month-old German shepherd dog were diagnosed with ear canal atresia. Based on presentation, computed tomography, and auditory function evaluation, the first dog underwent excision of the horizontal ear canal and bulla curettage, and the second underwent re-anastomosis of the vertical canal to the external meatus. Both dogs had successful outcomes.

  14. User's manual for semi-circular compact range reflector code

    NASA Technical Reports Server (NTRS)

    Gupta, Inder J.; Burnside, Walter D.

    1986-01-01

    A computer code was developed to analyze a semi-circular paraboloidal reflector antenna with a rolled edge at the top and a skirt at the bottom. The code can be used to compute the total near field of the antenna or its individual components at a given distance from the center of the paraboloid. Thus, it is very effective in computing the size of the sweet spot for RCS or antenna measurement. The operation of the code is described. Various input and output statements are explained. Some results obtained using the computer code are presented to illustrate the code's capability as well as being samples of input/output sets.

  15. 33 CFR 117.1045 - Hood Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... OPERATION REGULATIONS Specific Requirements Washington § 117.1045 Hood Canal. The draw of the Washington State pontoon highway bridge near Port Gamble operates as follows: (a) The draw shall open on signal if at least one hour's notice is given. The draw shall be opened horizontally for 300 feet unless the...

  16. 33 CFR 117.1045 - Hood Canal.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... OPERATION REGULATIONS Specific Requirements Washington § 117.1045 Hood Canal. The draw of the Washington State pontoon highway bridge near Port Gamble operates as follows: (a) The draw shall open on signal if at least one hour's notice is given. The draw shall be opened horizontally for 300 feet unless the...

  17. 33 CFR 117.1045 - Hood Canal.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... OPERATION REGULATIONS Specific Requirements Washington § 117.1045 Hood Canal. The draw of the Washington State pontoon highway bridge near Port Gamble operates as follows: (a) The draw shall open on signal if at least one hour's notice is given. The draw shall be opened horizontally for 300 feet unless the...

  18. Flow around a semicircular cylinder with passive flow control mechanisms

    NASA Astrophysics Data System (ADS)

    Hamed, A. M.; Vega, J.; Liu, B.; Chamorro, L. P.

    2017-03-01

    Wind tunnel experiments were performed to study the effect of passive flow control strategies on the wake and drag of a semicircular cylinder of infinite aspect ratio. High-resolution planar particle image velocimetry was used to obtain flow statistics around the semicircular cylinder at Reynolds number Re≈ 3.2× 10^4 based on the cylinder diameter. The control mechanisms under consideration include rigid flaps of various lengths placed at the edges of the structure and a small slot along the symmetry plane of the cylinder. Mean velocity fields reveal the distinctive effects of each passive mechanism on the flow, such as velocity recovery, size of the recirculation bubble and location of the reattachment point. The distributions of turbulence kinetic energy and kinematic shear stress show the modulation of each passive control mechanism on the wake, including the onset and location of the maximum turbulence levels. Instantaneous and mean fields of swirling strength further highlight the role of the passive mechanisms in the vortex dynamics. Drag coefficient for the various cases was estimated indirectly from the flow measurements using a momentum balance. This approach shows that long flaps and slot were able to reduce drag with respect to the base case. The rigid flaps with length coincident with the diameter of the cylinder offered the best performance with drag reduction of ˜25%.

  19. Vertical and torsional VOR in posterior canal occlusion.

    PubMed

    Kanayama, R; Bronstein, A M; Gresty, M A; Brookes, G B

    1995-01-01

    The vertical and torsional vestibulo-ocular reflexes (VOR) were investigated in 3 patients with surgical occlusion of the posterior semicircular canal and 1 patient with singular neurectomy, for treatment of refractory paroxysmal positional vertigo. Stimuli comprised sinusoidal oscillation in the coronal ("roll") and sagittal ("pitch") plane as well as in two oblique planes intermediate between pitch in order to stimulate left anterior + right posterior (LARP) and right anterior + left posterior (RALP) canal pairs separately. One case with left side BPPV was investigated pre and post-operatively. Depression of the vertical and torsional VOR gain was seen 1 week postoperatively when the occluded canal was placed in the optimal plane for stimulation at 1 week postoperatively and subsequently gradually recovered. Recordings in other planes suggested that the contralateral posterior canal was also hypofunctioning, a finding which may explain some residual gait unsteadiness in this case. The other 3 cases who were investigated postoperatively all showed a decrease in downward VOR gain in the "on' direction of the operated canal. The data indicate the specificity of the test procedure and underline the prognostic value of comprehensive pre-operative vestibular assessment.

  20. 27. VIEW OF TWIN FALLS MAIN CANAL HEADGATE WITH CANAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. VIEW OF TWIN FALLS MAIN CANAL HEADGATE WITH CANAL BRIDGE IN DISTANCE; LOOKING SOUTHWEST. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  1. 2. CANAL BOAT ENTERING THE DELAWARE CANAL FROM OF THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. CANAL BOAT ENTERING THE DELAWARE CANAL FROM OF THE LEHIGH RIVER. BOATS COULD BE FERRIED ACROSS THE DELAWARE RIVER TO THE MORRIS CANAL BY A CABLE SUPPORTED TROLLEY. - Morris Canal, Phillipsburg, Warren County, NJ

  2. Otolith-Canal Convergence In Vestibular Nuclei Neurons

    NASA Technical Reports Server (NTRS)

    Dickman, J. David; Si, Xiao-Hong

    2002-01-01

    The current final report covers the period from June 1, 1999 to May 31, 2002. The primary objective of the investigation was to determine how information regarding head movements and head position relative to gravity is received and processed by central vestibular nuclei neurons in the brainstem. Specialized receptors in the vestibular labyrinths of the inner ear function to detect angular and linear accelerations of the head, with receptors located in the semicircular canals transducing rotational head movements and receptors located in the otolith organs transducing changes in head position relative to gravity or linear accelerations of the head. The information from these different receptors is then transmitted to central vestibular nuclei neurons which process the input signals, then project the appropriate output information to the eye, head, and body musculature motor neurons to control compensatory reflexes. Although a number of studies have reported on the responsiveness of vestibular nuclei neurons, it has not yet been possible to determine precisely how these cells combine the information from the different angular and linear acceleration receptors into a correct neural output signal. In the present project, rotational and linear motion stimuli were separately delivered while recording responses from vestibular nuclei neurons that were characterized according to direct input from the labyrinth and eye movement sensitivity. Responses from neurons receiving convergent input from the semicircular canals and otolith organs were quantified and compared to non-convergent neurons.

  3. Atrioventricular Canal Defect

    MedlinePlus

    ... birth (congenital). The condition is often associated with Down syndrome. Atrioventricular canal defect allows extra blood to flow ... baby's heart is developing. Some factors, such as Down syndrome, might increase the risk of atrioventricular canal defect. ...

  4. Difference in trunk stability during semicircular turns with and without a bag in elderly women.

    PubMed

    Shin, Sun-Shil; Yoo, Won-Gyu; An, Duk-Hyun; Oh, Jae-Seop; Kim, Ki-Song; Kim, Tae-Ho; Choi, Jong-Sang

    2017-09-22

    Direction changes while walking are more likely to cause a hip fracture than is falling while walking in a straight line. Trunk stability is an important contributor to safe and effective walking, and arm movements influence trunk movement while walking. However, the difference in the trunk stability during semicircular turns performed by elderly women with a light bag has not been examined. To investigate the effects of carrying a bag on trunk stability during semicircular turns in elderly women. We enrolled 15 community-dwelling elderly women capable of independent walking. Participants walked with and without a bag at a self-selected speed along a marked path, which included semicircular turns, while fitted with an accelerometer attached over the L3 spinous process. Gait velocity was faster during semicircular turning with a bag versus without a bag. The normalized medial-lateral center of mass acceleration was lower during semicircular turning with a bag versus without a bag. We suggest that a light additional arm load and increased arm swing contributes to trunk stability and efficient walking during semicircular turning by elderly women.

  5. [Occupational semicircular lipoatrophy associated with serum adipokine abnormalities].

    PubMed

    Reinoso-Barbero, Luis; Díaz-Garrido, Ramón; González-Gómez, María-Fernanda; Olarrea, José; Gómez-Gallego, Félix; Bandrés, Fernando

    2015-10-21

    The aim of this study was to examine the relationship between semicircular lipoatrophy (SL), inflammation marker (high sensibility C-reactive protein [hs-CRP]), adipokines (leptine, chemerine and vaspine) and autoimmune markers (rheumatoid factor [RF], C3 and C4 complement fractions, antinuclear antibodies [ANA], HLA DR3, and DR4). Chemerine is an adipokine, but also is an immunity marker. A case-control study was performed in May 2013; 21 cases were included. The closest healthy coworker to each case was used as a control. We calculated Kruskal-Wallis nonparametric test. We found statistical significance (P<.05) between SL and raised hs-CRP, raised leptine and low chemerine. i) There seems to be an underlying inflammatory component (raised hs-CRP) in SL; ii) adipokine alteration (raised leptine and low chemerine) supports the idea that adipocytic differentiation is affected in SL, and iii) we have not found any immune marker associated with SL, except chemerine itself, which could explain a possible association between SL and immunity. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

  6. Designing Flaps for Closure of Circular and Semicircular Skin Defects.

    PubMed

    Alvarado, Alfredo

    2016-01-01

    Removing skin lesions from the human body is a simple procedure, but closing the resulting defect may prove a difficult task. The surgeon quite often encounters a problem when the lesion is located in a confined anatomical area where the elasticity of the skin is limited or when the lesion is large. To obviate these difficulties, I present 4 new incisions for closure of circular and semicircular skin defects on difficult parts of the human body such as the scalp, face, axilla, back, and sacrococcygeal areas. This article describes a working model made of white bond paper that can be enlarged or reduced in size using a regular copying machine that can be prepared in advance of surgery to make sure that it adapts to a particular anatomical location. Also, it describes a geometrical analysis in order to determine the distortion of the minimal tension lines of the skin, skin wastage, and length of the suture lines. In summary, it is possible to use a variety of skin incisions, taking advantage of the minimal tension lines of the skin and also taking into consideration the anatomical characteristics of the region involved.

  7. Root canal irrigants.

    PubMed

    Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu

    2010-10-01

    Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are discussed. We performed a Medline search for English-language papers published untill July 2010. The keywords used were 'root canal irrigants' and 'endodontic irrigants.' The reference lists of each article were manually checked for additional articles of relevance.

  8. Root canal irrigants

    PubMed Central

    Kandaswamy, Deivanayagam; Venkateshbabu, Nagendrababu

    2010-01-01

    Successful root canal therapy relies on the combination of proper instrumentation, irrigation, and obturation of the root canal. Of these three essential steps of root canal therapy, irrigation of the root canal is the most important determinant in the healing of the periapical tissues. The primary endodontic treatment goal must thus be to optimize root canal disinfection and to prevent reinfection. In this review of the literature, various irrigants and the interactions between irrigants are discussed. We performed a Medline search for English-language papers published untill July 2010. The keywords used were ‘root canal irrigants’ and ‘endodontic irrigants.’ The reference lists of each article were manually checked for additional articles of relevance. PMID:21217955

  9. Bitter Root Irrigation district canal, looking east, typical section (canal ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Bitter Root Irrigation district canal, looking east, typical section (canal full) - Bitter Root Irrigation Project, Bitter Root Irrigation Canal, Heading at Rock Creek Diversion Dam, West of U.S. Highway 93, Darby, Ravalli County, MT

  10. 14. Junction of the Tempe Canal and Western Canal, looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Junction of the Tempe Canal and Western Canal, looking north. Photographer: Mark Durben, February 1989. Source: SRPA - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

  11. Relationships between facial canal dehiscence and other intraoperative findings in chronic otitis media with cholesteatoma.

    PubMed

    Gülüstan, Filiz; Aslan, Hale; Songu, Murat; Başoğlu, Mehmet Sinan; Katılmış, Hüseyin

    2014-01-01

    We investigated the relationship between facial canal dehiscence and intraoperative middle ear and mastoid findings in patients operated on for cholesteatoma. We examined retrospectively 334 patients who had been operated on for cholesteatoma in Izmir Katip Celebi University, Ataturk Research and Training Hospital, ENT Clinic, between April 1997 and April 2010. The patients were examined for facial canal dehiscence according to age, gender, side of the ear, surgery type, first or revision surgery, localization of the facial canal dehiscence, spread of the cholesteatoma, with the presence of lateral semi-circular canal (LSCC) fistula and any defect in the ossicle chain, and destruction in the posterior wall of the external auditory canal(EAC). Of the patients, 23.6% had facial canal dehiscence and detected most commonly in the right ear 28.9% and tympanic segment, 83.5%. Facial canal dehiscence was found to be 24.2-fold more common in patients with LSCC fistula and 4.1-fold more common in patients with destruction in the posterior wall of the (EAC). In patients located cholesteatoma in tympanic cavity+antrum and the tympanic cavity+all mastoid cells and with incus and stapes defect, increased incidence of dehiscence. Age, first or revision operation and canal wall down tympanoplasty (CWDT) or canal wall up tympanoplasty (CWUT) did not affect the incidence of dehiscence. That the likelihood of facial canal dehiscence occurrence is increased in patients with LSSC fistulas, destruction in the posterior wall of the EAC, or a stapes defect is important information for surgeons. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Lumbar Spinal Canal Stenosis

    MedlinePlus

    ... time. This narrowing is called “stenosis.” As the lumbar spinal canal narrows, the nerves that go through it are squeezed. This squeezing ... chest). It’s thought that these positions “open” the lumbar canal and take the pressure off the nerves that go to the legs. In severe cases, ...

  13. New therapeutic maneuver for anterior canal benign paroxysmal positional vertigo.

    PubMed

    Yacovino, Dario A; Hain, Timothy C; Gualtieri, Francisco

    2009-11-01

    This article describes the clinical features of anterior semicircular canal benign paroxysmal positional vertigo (AC-BPPV) and a new therapeutic maneuver for its management. Our study was a retrospective review of cases from an ambulatory tertiary referral center. Thirteen patients afflicted with positional paroxysmal vertigo exhibiting brief positional down-beating nystagmus in positional tests (Dix-Hallpike and head-hanging position) were treated with a maneuver comprised of the following movements: Sequential head positioning beginning supine with head hanging 30 degrees dependent with respect to the body, then supine with head inclined 30 degrees forward, and ending sitting with head 30 degrees forward. All cases showed excellent therapeutic response to our repositioning procedure, i.e. relief of vertigo and elimination of nystagmus. The maneuver described is an option for AC-BPPV treatment.

  14. Identification of possible factors impacting dental students' ability to locate MB2 canals in maxillary molars.

    PubMed

    Park, Ellen; Chehroudi, Babak; Coil, Jeffrey M

    2014-05-01

    This study examined the effect of the access size and straight-line path of access on third-year dental students' ability to locate a second mesiobuccal (MB2) canal in maxillary first and second molars. One hundred and six third-year dental students at one Faculty of Dentistry performed simulated root canal treatment with the aid of 2x magnification loupes on extracted teeth. A postgraduate endodontic student subsequently made a reasonable search for an untreated MB2 canal with the aid of a dental operating microscope. The mesiobuccal roots were then sectioned horizontally for determination of the canal configuration. The dental students were able to treat an MB2 canal in 15.8 percent of the teeth, but this was not associated with satisfactory access criteria. The postgraduate endodontic student identified an MB2 canal in 54.7 percent of the remaining tooth samples excluding those where the MB2 canal was found by the dental students; this represented 94.3 percent of those teeth confirmed by horizontal sectioning of the root to have an MB2 canal. The postgraduate student troughed, on average, 2.6 mm before negotiating the MB2 canal. As satisfactory access criteria and straight-line path of access did not correlate with the dental students' ability to find a second mesiobuccal canal, this result has important implications for educational goals with respect to endodontic treatment of maxillary molar teeth.

  15. Otolith-Canal Convergence in Vestibular Nuclei Neurons

    NASA Technical Reports Server (NTRS)

    Dickman, J. David

    1996-01-01

    During manned spaceflight, acute vestibular disturbances often occur, leading to physical duress and a loss of performance. Vestibular adaptation to the weightless environment follows within two to three days yet the mechanisms responsible for the disturbance and subsequent adaptation are still unknown In order to understand vestibular system function in space and normal earth conditions the basic physiological mechanisms of vestibular information co coding must be determined. Information processing regarding head movement and head position with respect to gravity takes place in the vestibular nuclei neurons that receive signals From the semicircular canals and otolith organs in the vestibular labyrinth. These neurons must synthesize the information into a coded output signal that provides for the head and eye movement reflexes as well as the conscious perception of the body in three-dimensional space The current investigation will for the first time. determine how the vestibular nuclei neurons quantitatively synthesize afferent information from the different linear and angular acceleration receptors in the vestibular labyrinths into an integrated output signal. During the second year of funding, progress on the current project has been focused on the anatomical orientation of semicircular canals and the spatial orientation of the innervating afferent responses. This information is necessary in order to understand how vestibular nuclei neurons process the incoming afferent spatial signals particularly with the convergent otolith afferent signals that are also spatially distributed Since information from the vestibular nuclei is presented to different brain regions associated with differing reflexive and sensory functions it is important to understand the computational mechanisms used by vestibular neurons to produce the appropriate output signal.

  16. Bush Canal Floodgate Study

    DTIC Science & Technology

    2009-07-01

    ER D C/ CH L TR -0 9 -9 Bush Canal Floodgate Study Tate O. McAlpin, Rutherford C. Berger, and Amena M. Henville July 2009 C oa st...al a n d H yd ra u lic s La b or at or y Approved for public release; distribution is unlimited. ERDC/CHL TR-09-9 July 2009 Bush Canal ...LA 70118-3651 Under Military Interdepartmental Purchase Request (MIPR) W42HEM60734548, “H&H Modeling of Bush Canal /Morganza to the Gulf” ERDC/CHL

  17. Horizontal Eye Position Affects Measured Vertical VOR Gain on the Video Head Impulse Test.

    PubMed

    McGarvie, Leigh A; Martinez-Lopez, Marta; Burgess, Ann M; MacDougall, Hamish G; Curthoys, Ian S

    2015-01-01

    With the video head impulse test (vHIT), the vertical VOR gain is defined as (vertical eye velocity/vertical head velocity), but compensatory eye movements to vertical canal stimulation usually have a torsional component. To minimize the contribution of torsion to the eye movement measurement, the horizontal gaze direction should be directed 40° from straight ahead so it is in the plane of the stimulated canal plane pair. as gaze is systematically moved horizontally away from canal plane alignment, the measured vertical VOR gain should decrease. Ten healthy subjects, with vHIT measuring vertical eye movement to head impulses in the plane of the left anterior-right posterior (LARP) canal plane, with gaze at one of five horizontal gaze positions [40°(aligned with the LARP plane), 20°, 0°, -20°, -40°]. Every head impulse was in the LARP plane. The compensatory eye movement was measured by the vHIT prototype system. The one operator delivered every impulse. The canal stimulus remained identical across trials, but the measured vertical VOR gain decreased as horizontal gaze angle was shifted away from alignment with the LARP canal plane. In measuring vertical VOR gain with vHIT the horizontal gaze angle should be aligned with the canal plane under test.

  18. Horizontal Eye Position Affects Measured Vertical VOR Gain on the Video Head Impulse Test

    PubMed Central

    McGarvie, Leigh A.; Martinez-Lopez, Marta; Burgess, Ann M.; MacDougall, Hamish G.; Curthoys, Ian S.

    2015-01-01

    Background/hypothesis: With the video head impulse test (vHIT), the vertical VOR gain is defined as (vertical eye velocity/vertical head velocity), but compensatory eye movements to vertical canal stimulation usually have a torsional component. To minimize the contribution of torsion to the eye movement measurement, the horizontal gaze direction should be directed 40° from straight ahead so it is in the plane of the stimulated canal plane pair. Hypothesis: as gaze is systematically moved horizontally away from canal plane alignment, the measured vertical VOR gain should decrease. Study design: Ten healthy subjects, with vHIT measuring vertical eye movement to head impulses in the plane of the left anterior-right posterior (LARP) canal plane, with gaze at one of five horizontal gaze positions [40°(aligned with the LARP plane), 20°, 0°, −20°, −40°]. Methods: Every head impulse was in the LARP plane. The compensatory eye movement was measured by the vHIT prototype system. The one operator delivered every impulse. Results: The canal stimulus remained identical across trials, but the measured vertical VOR gain decreased as horizontal gaze angle was shifted away from alignment with the LARP canal plane. Conclusion: In measuring vertical VOR gain with vHIT the horizontal gaze angle should be aligned with the canal plane under test. PMID:25852637

  19. Panama Canal capacity analysis

    SciTech Connect

    Bronzini, M.S.

    1995-04-27

    Predicting the transit capacities of the various Panama Canal alternatives required analyzing data on present Canal operations, adapting and extending an existing computer simulation model, performing simulation runs for each of the alternatives, and using the simulation model outputs to develop capacity estimates. These activities are summarized in this paper. A more complete account may be found in the project final report (TAMS 1993). Some of the material in this paper also appeared in a previously published paper (Rosselli, Bronzini, and Weekly 1994).

  20. ASTER Suez Canal

    NASA Image and Video Library

    2000-10-06

    One of the most important waterways in the world, the Suez Canal runs north to south across the Isthmus of Suez in northeastern Egypt. This image of the canal covers an area 36 kilometers (22 miles) wide and 60 kilometers (47 miles) long in three bands of the reflected visible and infrared wavelength region. It shows the northern part of the canal, with the Mediterranean Sea just visible in the upper right corner. The Suez Canal connects the Mediterranean Sea with the Gulf of Suez, an arm of the Red Sea. The artificial canal provides an important shortcut for ships operating between both European and American ports and ports located in southern Asia, eastern Africa, and Oceania. With a length of about 195 kilometers (121 miles) and a minimum channel width of 60 meters (197 feet), the Suez Canal is able to accommodate ships as large as 150,000 tons fully loaded. Because no locks interrupt traffic on this sea level waterway, the transit time only averages about 15 hours. ASTER acquired this scene on May 19, 2000. http://photojournal.jpl.nasa.gov/catalog/PIA02661

  1. Superior Canal Dehiscence Syndrome Affecting 3 Families.

    PubMed

    Heidenreich, Katherine D; Kileny, Paul R; Ahmed, Sameer; El-Kashlan, Hussam K; Melendez, Tori L; Basura, Gregory J; Lesperance, Marci M

    2017-07-01

    Superior canal dehiscence syndrome (SCDS) is an increasingly recognized cause of hearing loss and vestibular symptoms, but the etiology of this condition remains unknown. To describe 7 cases of SCDS across 3 families. This retrospective case series included 7 patients from 3 different families treated at a neurotology clinic at a tertiary academic medical center from 2010 to 2014. Patients were referred by other otolaryngologists or were self-referred. Each patient demonstrated unilateral or bilateral SCDS or near dehiscence. Clinical evaluation involved body mass index calculation, audiometry, cervical vestibular evoked myogenic potential testing, electrocochleography, and multiplanar computed tomographic (CT) scan of the temporal bones. Zygosity testing was performed on twin siblings. The diagnosis of SCDS was made if bone was absent over the superior semicircular canal on 2 consecutive CT images, in addition to 1 physiologic sign consistent with labyrinthine dehiscence. Near dehiscence was defined as absent bone on only 1 CT image but with symptoms and at least 1 physiologic sign of labyrinthine dehiscence. A total of 7 patients (5 female and 2 male; age range, 8-49 years) from 3 families underwent evaluation. Family A consisted of 3 adult first-degree relatives, of whom 2 were diagnosed with SCDS and 1 with near dehiscence. Family B included a mother and her child, both of whom were diagnosed with unilateral SCDS. Family C consisted of adult monozygotic twins, each of whom was diagnosed with unilateral SCDS. For all cases, dehiscence was located at the arcuate eminence. Obesity alone did not explain the occurrence of SCDS because 5 of the 7 cases had a body mass index (calculated as weight in kilograms divided by height in meters squared) less than 30.0. Superior canal dehiscence syndrome is a rare, often unrecognized condition. This report of 3 multiplex families with SCDS provides evidence in support of a potential genetic contribution to the etiology

  2. Vibration of Thin Circular Rings. Part II. Modal Functions and Eigenvalues of Constrained Semicircular Rings

    NASA Technical Reports Server (NTRS)

    Lang, T. E.

    1963-01-01

    The equations of motion of thin circular rings are derived and solved for in-plane in-extensional deformation. Modal characteristics are tabulated for the five lowest flexural modes of vibration of semicircular ring segments for the possible combinations of homogeneous boundary conditions that can occur.

  3. 10. VIEW EAST, RECESS AREA WITH BOTTOM HORIZONTAL BEAM FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. VIEW EAST, RECESS AREA WITH BOTTOM HORIZONTAL BEAM FOR EAST GATE - Bald Eagle Cross-Cut Canal Lock, North of Water Street along West Branch of Susquehanna River South bank, 500 feet East of Jay Street Bridge, Lock Haven, Clinton County, PA

  4. 55. View of junction of unlined canal and lined canal, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    55. View of junction of unlined canal and lined canal, looking southwest. Photo by Brian C. Morris, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  5. 54. View of junction of unlined canal and lined canal, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    54. View of junction of unlined canal and lined canal, looking southwest. Photo by Brian C. Morris, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  6. 56. View of lined canal looking east toward unlined canal, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    56. View of lined canal looking east toward unlined canal, from road bridge crossing lined canal. Photo by Brian C. Morris, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  7. Love canal questions

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    The Environmental Protection Agency (EPA) conducted a 3-month monitoring study of the Love Canal area near Niagara Falls, N.Y., after the federal government pronounced that a potential health risk existed due to chemical waste dumps. In 1982 the Department of Health and Human Services (HHS) decided that the area was habitable, subject to implementation of effective safeguards against leakage from the canal and to cleaning up of the contaminants. Now, the Congressional Office of Technology Assessment (OTA) has announced that, with the information available, it is not possible to demonstrate with certainty that unsafe levels do not exist within the so-called “emergency declaration area” (EDA).

  8. Fabrication and characterization of semicircular detection electrodes for contactless conductivity detector - CE microchips.

    PubMed

    Lee, Chia-Yen; Chen, C M; Chang, Guan-Liang; Lin, Che-Hsin; Fu, Lung-Ming

    2006-12-01

    This study uses simple and reliable microfabrication techniques to fabricate CE biochips, integrating a novel contactless conductivity detector in a miniaturized detection system in a microfluidic biochip. The off-channel electrodes are deposited around side channels by Au sputtering and patterned using a standard "lift-off" process. A vacuum fusion bonding process is employed to seal the lower substrate containing the microchannels and the electrodes to an upper glass cover plate. The variations in the capacitance between the semicircular detection electrodes in the side channels are measured as different samples and ions pass through the detection region of the CE separation channel. Samples of Rhodamine B, commercial sports drinks, mineral waters, and a red wine, respectively, are mixed in different buffer solutions, separated, and successfully detected using the developed device. The semicircular detection electrodes for the contactless conductivity detector have microscale dimensions and provide a valuable contribution to the realization of the lab-on-a-chip concept.

  9. Fully continuous liquid crystal diffraction grating with alternating semi-circular alignment by imprinting.

    PubMed

    Kim, Jiyoon; Na, Jun-Hee; Lee, Sin-Doo

    2012-01-30

    We demonstrate a fully continuous liquid crystal (LC) grating device with the alternating semi-circular alignment which exhibits the switching effect between the diffraction orders independent of the thickness of the LC cell. The continuous phase modulation in the LC grating with the rotational symmetry was achieved on a micro-imprinted surface where the semi-circular alignment of the LC was spontaneously produced. Our LC grating device in the hybrid geometry exhibited the perfect continuity of the phase retardation and the switchable diffraction with the diffraction efficiency of 44% at ±1st orders as a function of an applied voltage. It was found that the symmetry of the input polarization direction with respect to the grating patterns results in the interchange between two symmetric grating configurations.

  10. Integrated plasmonic semi-circular launcher for dielectric-loaded surface plasmon-polariton waveguide.

    PubMed

    Li, Xiaowei; Huang, Lingling; Tan, Qiaofeng; Bai, Benfeng; Jin, Guofan

    2011-03-28

    A semi-circular plasmonic launcher integrated with dielectric-loaded surface plasmon-polaritons waveguide (DLSPPW) is proposed and analyzed theoretically, which can focus and efficiently couple the excited surface plasmon polaritons (SPPs) into the DLSPPW via the highly matched spatial field distribution with the waveguide mode in the focal plane. By tuning the incident angle or polarization of the illuminating beam, it is shown that the launcher may be conveniently used as a switch or a multiplexer that have potential applications in plasmonic circuitry. Furthermore, from an applicational point of view, it is analyzed how the coupling performance of the launcher can be further improved by employing multiple semi-circular slits.

  11. Horizontal drilling developments

    SciTech Connect

    Gust, D.

    1997-05-01

    The advantages of horizontal drilling are discussed. Use of horizontal drilling has climbed in the past half decade as technology and familiarity offset higher costs with higher production rates and greater recoveries from new and existing wells. In essence, all types of horizontal wells expose a larger section of the reservoir to the wellbore with a resulting increase in flow rates. (A horizontal well may also be drilled to provide coning control or to intersect vertical fractures.) Thus, drilling horizontally, both onshore and offshore, reduces the number of wells necessary to develop a field.

  12. Histopathological incidence of facial canal dehiscence in otosclerosis.

    PubMed

    Nomiya, Shigenobu; Cureoglu, Sebahattin; Kariya, Shin; Morita, Norimasa; Nomiya, Rie; Nishizaki, Kazunori; Paparella, Michael M

    2011-09-01

    The objective of this study was to evaluate the histopathological incidence of facial canal dehiscence in otosclerosis cases compared with non-otosclerotic controls. 133 temporal bones from 84 otosclerosis (35 unilateral otosclerosis, 49 bilateral otosclerosis) cases were compared to 102 age-matched normal temporal bones from 70 subjects (38 unilateral normal cases, 32 bilateral normal cases). Temporal bones were serially sectioned in the horizontal plane at a thickness of 20 μm, and were stained with hematoxylin and eosin. We evaluated the location and the invasion of otosclerosis to the facial canal and incidence of facial canal dehiscence under light microscopy. Facial canal was subdivided into four portions: (1) the geniculate ganglion, (2) the tensor tympani muscle, (3) the oval window, and (4) mastoid. The incidence of facial canal dehiscence in otosclerosis [66 temporal bones (49.6%)] was significantly lower than normal controls [67 control temporal bones (65.7%)] in the oval window area (P = 0.019). Temporal bones with otosclerotic invasion to the thin bone of the canal were significantly less likely to have dehiscence [10 temporal bones (31.3%)] compared to the otosclerotic bones without invasion [56 temporal bones (55.5%)] (P = 0.025). There was no significant difference in the incidence of facial canal dehiscence between temporal bones with and without otosclerosis in the entire segment of facial nerve. Our findings in this study suggest that otosclerotic lesions have the potential to close dehiscence of the facial canal in the oval window area.

  13. Stress Intensity Factors of Semi-Circular Bend Specimens with Straight-Through and Chevron Notches

    NASA Astrophysics Data System (ADS)

    Ayatollahi, M. R.; Mahdavi, E.; Alborzi, M. J.; Obara, Y.

    2016-04-01

    Semi-circular bend specimen is one of the useful test specimens for determining fracture toughness of rock and geo-materials. Generally, in rock test specimens, initial cracks are produced in two shapes: straight-edge cracks and chevron notches. In this study, the minimum dimensionless stress intensity factors of semi-circular bend specimen (SCB) with straight-through and chevron notches are calculated. First, using finite element analysis, a suitable relation for the dimensionless stress intensity factor of SCB with straight-through crack is presented based on the normalized crack length and half-distance between supports. For evaluating the validity and accuracy of this relation, the obtained results are then compared with numerical and experimental results reported in the literature. Subsequently, by performing some experiments and also finite element analysis of the SCB specimen with chevron notch, the minimum dimensionless stress intensity factor of this specimen is obtained. Using the new equation for the dimensionless stress intensity factor of SCB with straight-through crack and an analytical method, i.e., Bluhm's slice synthesis method, the minimum (critical) dimensionless stress intensity factor of chevron notched semi-circular bend specimens is calculated. Good agreement is observed between the results of two mentioned methods.

  14. Panama: Owning the Canal

    DTIC Science & Technology

    2014-03-01

    47 Herbert Knapp and Mary Knapp, Red, White and Blue Paradise : The American Canal Zone in Panama (New York: Harcourt Brace Jovanovich...1984), 54–55. 48 Knapp and Knapp, Red, White and Blue Paradise , 55–56. 49 Conniff, Panama and The United States, 122. 20 legislatures and thus...Czechoslovakia, during the Cold War, while the United States still treated the small nation of Panama as an imperialistic conquest, was not lost on Carter

  15. Vestibular-evoked myogenic potential thresholds normalize on plugging superior canal dehiscence.

    PubMed

    Welgampola, Miriam S; Myrie, Oluwaseun A; Minor, Lloyd B; Carey, John P

    2008-02-05

    Diagnosis of the superior canal dehiscence syndrome (SCDS) relies on symptoms such as sound- or pressure-induced vertigo or oscillopsia, demonstration of sound or pressure-evoked vertical/torsional eye movements, and the presence of a defect in the bony roof overlying the superior semicircular canal. Lowered thresholds for eliciting vestibular-evoked myogenic potentials (VEMPs) provide additional conformation. To examine VEMP characteristics before and after canal plugging for SCDS. VEMPs evoked by air- and bone-conducted tones were measured from the sternocleidomastoid muscles (cVEMP) and periocular sites (oVEMP) of 20 normal volunteers, 10 newly diagnosed subjects with SCDS, and 12 subjects who underwent successful superior canal plugging. In all SCDS ears, thresholds for evoking VEMP using air-conducted tones were pathologically lowered, with average values of 83.85 +/- 1.40 dB sound pressure level (SPL) for cVEMP and 85.38 +/- 1.32 dB SPL for oVEMP, 20 to 30 dB below those of controls. Successful canal plugging resulted in normal reflex thresholds. For bone vibration, average thresholds in SCDS ears were 114.62 +/- 1.54 dB FL (force level) for cVEMP and 116.0 +/- 1.52 dB FL for oVEMP, 10 to 20 dB below controls, yet three SCDS ears had normal thresholds. Ocular and cervical vestibular-evoked myogenic potentials evoked by air-conducted sound are equally useful in the diagnosis and follow-up of superior canal dehiscence syndrome. Stimulus thresholds are consistently lowered upon presentation and normalize after corrective surgery. Thresholds for bone vibration, in contrast, have a lower diagnostic yield.

  16. BAER testing in a dog with bilateral external ear canal atresia.

    PubMed

    Anwer, Cona; Schwarz, Tobias; Volk, Susan W; Vite, Charles

    2011-01-01

    A 3 yr old male castrated Labrador retriever presented for evaluation and treatment of bilateral atresia of the external ear canals. The owners reported that the dog could hear only loud and high-pitched noises. Computed tomography of the head revealed intact vertical and horizontal ear canals filled with debris and a debris-filled right tympanic bulla. Air- and bone-conducted brainstem auditory evoked response (BAER) testing revealed an elevated response threshold to air-conducted stimuli and greater amplitude waveforms evoked by bone-conducted stimuli. The ear canals were surgically corrected via lateral ear canal resection. BAER testing postoperatively revealed a decrease in the air-conducted BAER threshold. This case is an example of the use of bone-conducted BAER testing to aid in the diagnosis of conductive deafness, and in determining prognosis for normal hearing after surgical treatment of external ear canal atresia.

  17. Distributed control at Love canal

    SciTech Connect

    McPherson, G.; Rider, G.J.; Sadowski, B.; Moore, M.

    1994-09-01

    Love Canal is known worldwide as the site of one of the worst non-nuclear environmental disasters in modern history. For 12 years, a Niagara Falls, New York chemical company used the canal bed as a chemical dump. This article discusses the computerized control of equipment used to remove the toxic materials from the ground under Love Canal, and how the minimization of maintenance is reducing maintenance costs and increasing operator safety.

  18. ASTER Suez Canal

    NASA Technical Reports Server (NTRS)

    2000-01-01

    One of the most important waterways in the world, the Suez Canal runs north to south across the Isthmus of Suez in northeastern Egypt. This image of the canal covers an area 36 kilometers (22 miles) wide and 60 kilometers (47 miles) long in three bands of the reflected visible and infrared wavelength region. It shows the northern part of the canal, with the Mediterranean Sea just visible in the upper right corner. The Suez Canal connects the Mediterranean Sea with the Gulf of Suez, an arm of the Red Sea. The artificial canal provides an important shortcut for ships operating between both European and American ports and ports located in southern Asia, eastern Africa, and Oceania. With a length of about 195 kilometers (121 miles) and a minimum channel width of 60 meters (197 feet), the Suez Canal is able to accommodate ships as large as 150,000 tons fully loaded. Because no locks interrupt traffic on this sea level waterway, the transit time only averages about 15 hours. ASTER acquired this scene on May 19, 2000.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five

  19. ASTER Suez Canal

    NASA Technical Reports Server (NTRS)

    2000-01-01

    One of the most important waterways in the world, the Suez Canal runs north to south across the Isthmus of Suez in northeastern Egypt. This image of the canal covers an area 36 kilometers (22 miles) wide and 60 kilometers (47 miles) long in three bands of the reflected visible and infrared wavelength region. It shows the northern part of the canal, with the Mediterranean Sea just visible in the upper right corner. The Suez Canal connects the Mediterranean Sea with the Gulf of Suez, an arm of the Red Sea. The artificial canal provides an important shortcut for ships operating between both European and American ports and ports located in southern Asia, eastern Africa, and Oceania. With a length of about 195 kilometers (121 miles) and a minimum channel width of 60 meters (197 feet), the Suez Canal is able to accommodate ships as large as 150,000 tons fully loaded. Because no locks interrupt traffic on this sea level waterway, the transit time only averages about 15 hours. ASTER acquired this scene on May 19, 2000.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five

  20. Controversy at Love Canal.

    PubMed

    Paigen, B

    1982-06-01

    A cancer researcher reviews the events surrounding the toxic waste contamination at Love Canal with emphasis on the political nature of the controversy about its health impact. Antagonism between the community and the New York State Department of Health was fueled by several factors: the state's awareness that it gained from delay in investigation, disagreement on health problems to be studied, control over the information gathering process, silencing of opposition opinion, and the violation of norms of scientific behavior. The author calls for the establishment of standards of ethical behavior for scientists in such situations, standards for conflict resolution, and means of appeal for those injured.

  1. 15. ROUTE OF CANAL NORTHWEST OF THE DILLON CEMETERY. CANAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. ROUTE OF CANAL NORTHWEST OF THE DILLON CEMETERY. CANAL PASSES BELOW HILLSIDE IN FOREGROUND, THROUGH THE LOWER EDGE OF THE TREES ON LEFT, ON FAR SIDE OF SMALL VALLEY JUST RIGHT OF CENTER, AND AROUND THE PROMINENT POINT ON THE RIGHT. VIEW IS TO THE EAST-SOUTHEAST. - Snake River Ditch, Headgate on north bank of Snake River, Dillon, Summit County, CO

  2. Osmolarity and root canal antiseptics.

    PubMed

    Rossi-Fedele, G; Guastalli, A R

    2014-04-01

    Antiseptics used in endodontics for disinfection purposes include root canal dressings and irrigants. Osmotic shock is known to cause the alteration of microbial cell viability and might have a role in the mechanism of action of root canal antiseptics. The aim of this review was to determine the role of osmolarity on the performance of antiseptics in root canal treatment. A literature search using the Medline electronic database was conducted up to 30 May 2013 using the following search terms and combinations: 'osmolarity AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmolality AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmotic AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; osmosis AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm; sodium chloride AND root canal or endodontic or antiseptic or irrigation or irrigant or medication or dressing or biofilm'. Publications were included if the effects of osmolarity on the clinical performance of antiseptics in root canal treatment were stated, if preparations with different osmolarities values were compared and if they were published in English. A hand search of articles published online, 'in press' and 'early view', and in the reference list of the included papers was carried out following the same criteria. A total of 3274 publications were identified using the database, and three were included in the review. The evidence available in endodontics suggests a possible role for hyperosmotic root canal medicaments as disinfectants, and that there is no influence of osmolarity on the tissue dissolution capacity of sodium hypochlorite. There are insufficient data to obtain a sound conclusion regarding the role of hypo-osmosis in root canal disinfection, or osmosis in any further desirable

  3. Vortex shedding and galloping of open semi-circular and parabolic cylinders in cross-flow

    NASA Astrophysics Data System (ADS)

    Weaver, D. S.; Veljkovic, I.

    2005-11-01

    An experimental wind-tunnel study was undertaken to investigate the flow-induced vibration behaviour of open semi-circular and parabolic cylinders in cross-flow. The motivation for the research was to investigate the cause of the fatigue failures of a number of parabolic section rotary mixing blades in a large mixing vessel. Results are presented for force coefficients as a function of angle of incidence of the flow, Strouhal number and amplitude response. It is shown that the parabolic cylinder is subject to large amplitude vortex shedding resonance and, when the elastic axis is sufficiently downstream of the section's centre of gravity, galloping instability.

  4. Your baby in the birth canal

    MedlinePlus

    ... lie; Fetal attitude; Fetal descent; Fetal station; Cardinal movements; Labor-birth canal; Delivery-birth canal ... are used to describe your baby's position and movement through the birth canal. FETAL STATION Fetal station ...

  5. Bilateral internal acoustic canal mass.

    PubMed

    Nazim, Korkut; Mehmet, Yilmaz; Tuna, Edizer Deniz; Marlen, Mamanov Asanbekovich

    2013-01-01

    We reported a case of bilateral internal acoustic canal mass. A 42-year-old man patient was previously treated for colon cancer. After surgery during chemotherapy signs as severe vertigo and bilateral sudden hearing loss occurred. Temporal bone magnetic resonance imaging (MRI) had bilateral internal acoustic canal masses.

  6. [Difficulties and misunderstandings of root canal filling].

    PubMed

    Chen, Zhang

    2017-06-01

    Root canal filling is performed as the final and most important procedure of root canal treatment. The superior 3D filling is the key determinant of endodontic success. However, such procedure remains a challenge because of the complexity of the root canal system and the limitation of root canal filling materials and methods. This paper provides an overview of current principles and practices in root canal filling, focusing on advantages, disadvantages and indications. The process errors and countermeasures in various root canal filling methods are also discussed. This review provides guidance and help for clinical and practice to achieve a satisfactory root canal filling and improve root canal treatment outcome.

  7. MR imaging of the internal auditory canal and inner ear at 3T: comparison between 3D driven equilibrium and 3D balanced fast field echo sequences.

    PubMed

    Byun, Jun Soo; Kim, Hyung Jin; Yim, Yoo Jeong; Kim, Sung Tae; Jeon, Pyoung; Kim, Keon Ha; Kim, Sam Soo; Jeon, Yong Hwan; Lee, Jiwon

    2008-01-01

    To compare the use of 3D driven equilibrium (DRIVE) imaging with 3D balanced fast field echo (bFFE) imaging in the assessment of the anatomic structures of the internal auditory canal (IAC) and inner ear at 3 Tesla (T). Thirty ears of 15 subjects (7 men and 8 women; age range, 22-71 years; average age, 50 years) without evidence of ear problems were examined on a whole-body 3T MR scanner with both 3D DRIVE and 3D bFFE sequences by using an 8-channel sensitivity encoding (SENSE) head coil. Two neuroradiologists reviewed both MR images with particular attention to the visibility of the anatomic structures, including four branches of the cranial nerves within the IAC, anatomic structures of the cochlea, vestibule, and three semicircular canals. Although both techniques provided images of relatively good quality, the 3D DRIVE sequence was somewhat superior to the 3D bFFE sequence. The discrepancies were more prominent for the basal turn of the cochlea, vestibule, and all semicircular canals, and were thought to be attributed to the presence of greater magnetic susceptibility artifacts inherent to gradient-echo techniques such as bFFE. Because of higher image quality and less susceptibility artifacts, we highly recommend the employment of 3D DRIVE imaging as the MR imaging choice for the IAC and inner ear.

  8. Proposal for a simple and effective diagrammatic representation of root canal configuration for better communication amongst oral radiologists and clinicians

    PubMed Central

    Gupta, Saurabh Kumar; Saxena, Payal

    2015-01-01

    Objectives Root canal anatomy has been proved to be a complex canal configuration system. The negotiation and cleaning of this system is essential for successful root canal treatment. The present root canal classification systems are unable to transfer the clinically relevant information about the canal system from the oral radiologist to the treating clinician. Thus, a simple and effective diagrammatic representation of the canal system, depicting the major canals, important changes during their course along with other relevant information has been presented. Methods The proposed representation consists of five horizontal lines dividing the tooth into four segments from the point of reference to apical foramen. Each line has been designated with different line style. The diagrammatic images, one anterior and one posterior multi-rooted tooth, are given for easy understanding of the orientation of image. The whole image can be saved in portable network graphics format and can be imported to any word processing document. The image can be printed in the reporting sheet. Result Applying the same proposal, some of the diagrammatic representations have been showed. Conclusion This proposal for diagrammatic representation of root canal configuration can be helpful in getting an approximate distribution of the canals in a relatively simple manner. This scheme also provides valuable clinical information about the root canal system, which the other classifications fail to represent. PMID:26937372

  9. Horizontal Cross Bracing Detail, Vertical Cross Bracing Detail, Horizontal Cross ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Horizontal Cross Bracing Detail, Vertical Cross Bracing Detail, Horizontal Cross Bracing Detail, Vertical Cross Bracing-End Detail - Cumberland Covered Bridge, Spanning Mississinewa River, Matthews, Grant County, IN

  10. Otolith and Vertical Canal Contributions to Dynamic Postural Control

    NASA Technical Reports Server (NTRS)

    Black, F. Owen

    1999-01-01

    The objective of this project is to determine: 1) how do normal subjects adjust postural movements in response to changing or altered otolith input, for example, due to aging? and 2) how do patients adapt postural control after altered unilateral or bilateral vestibular sensory inputs such as ablative inner ear surgery or ototoxicity, respectively? The following hypotheses are under investigation: 1) selective alteration of otolith input or abnormalities of otolith receptor function will result in distinctive spatial, frequency, and temporal patterns of head movements and body postural sway dynamics. 2) subjects with reduced, altered, or absent vertical semicircular canal receptor sensitivity but normal otolith receptor function or vice versa, should show predictable alterations of body and head movement strategies essential for the control of postural sway and movement. The effect of altered postural movement control upon compensation and/or adaptation will be determined. These experiments provide data for the development of computational models of postural control in normals, vestibular deficient subjects and normal humans exposed to unusual force environments, including orbital space flight.

  11. Superior canal dehiscence syndrome associated with scuba diving.

    PubMed

    Kitajima, Naoharu; Sugita-Kitajima, Akemi; Kitajima, Seiji

    2017-06-01

    A 28-year-old female diver presented with dizziness and difficulty clearing her left ear whilst scuba diving. Her pure-tone audiometry and tympanometry were normal. Testing of Eustachian tube function revealed tubal stenosis. Video-oculography revealed a predominantly torsional nystagmus while the patient was in the lordotic position. Fistula signs were positive. High-resolution computed tomography (HRCT) of the temporal bone revealed a diagnosis of bilateral superior semicircular canal dehiscence (SCDS). Cervical vestibular-evoked myogenic potential (cVEMP) testing showed that the amplitude of the cVEMP measured from her left ear was larger than that from the right. In electronystagmography (ENG), nose-pinched Valsalva manoeuvres caused eye movements to be mainly directed counterclockwise with a vertical component. Tullio phenomenon was also positive for both ears. SCDS patients tend to be misdiagnosed and misunderstood; common misdiagnoses in these cases are alternobaric vertigo (AV), inner ear barotrauma, and inner-ear decompression sickness. It is difficult to diagnose vertigo attacks after scuba diving as SCDS; however, when the patient develops sound- and/or pressure-induced vertical-torsional nystagmus, HRCT should be conducted to confirm a diagnosis of SCDS.

  12. 173. CANAL TENDER OPERATING LOCK MACHINERY ON THE MORRIS CANAL. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    173. CANAL TENDER OPERATING LOCK MACHINERY ON THE MORRIS CANAL. AS THE LOCK TENDER TURNS THE CRANK, A SMALL COGGED WHEEL (PINION) ON THE CRANK TURNS A LARGER COGGED WHEEL, (MAIN GEAR). MAIN GEAR ENGAGES A COGGED BAR CALLED A TRAVELLER WHICH MOVES FORWARD OR BACK DEPENDING ON WHICH WAY THE CRANK IS TURNED. CONNECTED TO THE TRAVELLER ARE TO LONG RODS (GATE ARMS) WHICH IN TURN ARE CONNECTED TO THE GATE'S TOP BEAM (ONE FOR EACH GATE). AS THE TRAVELLER MOVES FORWARD THE GATE ARMS EXTEND PUSHING THE GATES OPEN. - Morris Canal, Phillipsburg, Warren County, NJ

  13. Panama City and Canal

    NASA Image and Video Library

    1994-09-30

    STS068-237-099 (30 September-11 October 1994) --- This 70mm frame shows the Panama Canal (center, between the two dark green belts) the main ship way to travel from the Atlantic to the Pacific Ocean. Also seen is a great deal of detail in Panama City (left center, on the Pacific Ocean coastline). Geologists studying the photography returned by Shuttle astronauts feel this picture is the best ever of the city. Agricultural fields can be seen on the east side of Panama City and on both sides of the Pan American Highway (the straight thin line extending to the left). Sedimentation in the Chepo River (upper left) is thought to be due to eroded soil from the agricultural lands near the sea. This river is surrounded by swamps lying along the Pacific coastline.

  14. 38. James River and Kanawha Canal Locks. The canal, which ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. James River and Kanawha Canal Locks. The canal, which operated between 1835 to 1880, serves as the focal point of the area's interpretation. The Battery Creek Lock was reconstructed between 1961 and 1965. Severe flooding in 1985 damaged the lock gates which were reconstructed in 1987-88. The view is to the south. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  15. Method for Constructing Standardized Simulated Root Canals.

    ERIC Educational Resources Information Center

    Schulz-Bongert, Udo; Weine, Franklin S.

    1990-01-01

    The construction of visual and manipulative aids, clear resin blocks with root-canal-like spaces, for simulation of root canals is explained. Time, materials, and techniques are discussed. The method allows for comparison of canals, creation of any configuration of canals, and easy presentation during instruction. (MSE)

  16. Method for Constructing Standardized Simulated Root Canals.

    ERIC Educational Resources Information Center

    Schulz-Bongert, Udo; Weine, Franklin S.

    1990-01-01

    The construction of visual and manipulative aids, clear resin blocks with root-canal-like spaces, for simulation of root canals is explained. Time, materials, and techniques are discussed. The method allows for comparison of canals, creation of any configuration of canals, and easy presentation during instruction. (MSE)

  17. [Influence of different ultrasonic irrigation solutions after root canal preparation with ProTaper by machine on micro-hardness of root canal dentin].

    PubMed

    Guo, Jiang-li; Zhang, Yan; Zhen, Lei

    2015-08-01

    To develope the influence of different ultrasonic irrigations after root canal preparation with nickel titanium ProTaper on micro-hardness of root canal dentin. Sixty of maxillary anterior teeth with single-canal were collected and randomly divided into 6 groups. Group A was control group, group B was prepared to F3 with nickel titanium ProTaper by machine, group C was ultrasonic irrigated with 3% hydrogen peroxide solution for 1 minute after preparation, group D was ultrasonic irrigated with koutai mouthwash for 1 minute after preparation, group E was ultrasonic irrigated with 17% EDTA solution for 1 minute after preparation, group F was ultrasonic irrigated with distilled water for 1 minute after preparation. The roots were then sectioned horizontally into 3 parts, split longitudinally into halves and examined under a micro Vickers hardness test machine. The data was analyzed by one-way ANOVA and t test with SPSS 17.0 software package. The micro-hardness of group A was (52.66 ± 1.64) HV,(52.08 ± 1.53) HV and (51.47 ± 2.53) HV. There was no significant difference in all parts of the root canal in group A (P>0.05). The micro-hardness of the apical third of root canal was lower than that of the cervical and middle of root canal in the other groups (P<0.05). In the cervical and middle third of the root canals, the micro-hardness of group E was (44.65 ± 1.33) HV and(42.55 ± 1.12) HV, and there were statistical significances between group E and the other groups (P<0.05). In the apical third of root canal,the micro-hardness of group E was (37.82 ± 1.60) HV, and group C was (44.14±1.73) HV, both of the comparative differences with other groups were statistically significant (P<0.05). There was no significant difference among group B, group D and group F (P>0.05). Root canal preparation to F3 with nickel titanium ProTaper by machine can make the micro-hardness of the apical third of root canal decrease. Ultrasonic irrigation with 17% EDTA solution for 1 minute can

  18. The Love Canal: Beyond science?

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    When in 1978, the New York State Department of Health issued the report, ‘Love Canal—Public Health Time Bomb,’ the serious effects of chemical waste contamination in the Love Canal area became an issue of national concern. A few ‘studies’ since then have produced results in concert with those of initial reports that described ‘conditions of acute health effects’ as being linked to hazardous wastes incorporated in landfill in the Love Canal site near Niagara Falls, New York. Now that a ‘blue ribbon’ panel of experts from the medical sciences has reviewed the problems of Love Canal, however, a different view has emerged. The ‘Report of the Governors' Panel to Review Scientific Studies and the Development of Public Policy on Problems Resulting from Hazardous Wastes,’ transmitted in October of this year, identifies the following factors about the health effects at Love Canal:

  19. Ultrasonic cleaning of root canals

    NASA Astrophysics Data System (ADS)

    Verhaagen, Bram; Boutsioukis, Christos; Jiang, Lei-Meng; Macedo, Ricardo; van der Sluis, Luc; Versluis, Michel

    2011-11-01

    A crucial step during a dental root canal treatment is irrigation, where an antimicrobial fluid is injected into the root canal system to eradicate all bacteria. Agitation of the fluid using an ultrasonically vibrating miniature file has shown significant improvement in cleaning efficacy over conventional syringe irrigation. However, the physical mechanisms underlying the cleaning process, being acoustic streaming, cavitation or chemical activity, and combinations thereof, are not fully understood. High-speed imaging allows us to visualize the flow pattern and cavitation in a root canal model at microscopic scales, at timescales relevant to the cleaning processes (microseconds). MicroPIV measurements of the induced acoustic streaming are coupled to the oscillation characteristics of the file as simulated numerically and measured with a laser vibrometer. The results give new insight into the role of acoustic streaming and the importance of the confinement for the cleaning of root canals.

  20. Horizontal Advanced Tensiometer

    SciTech Connect

    Hubbell, Joel M.; Sisson, James B.

    2004-06-22

    An horizontal advanced tensiometer is described that allows the monitoring of the water pressure of soil positions, particularly beneath objects or materials that inhibit the use of previous monitoring wells. The tensiometer includes a porous cup, a pressure transducer (with an attached gasket device), an adaptive chamber, at least one outer guide tube which allows access to the desired horizontal position, a transducer wire, a data logger and preferably an inner guide tube and a specialized joint which provides pressure on the inner guide tube to maintain the seal between the gasket of the transducer and the adaptive chamber.

  1. Horizontal Advanced Tensiometer

    DOEpatents

    Hubbell, Joel M.; Sisson, James B.

    2004-06-22

    An horizontal advanced tensiometer is described that allows the monitoring of the water pressure of soil positions, particularly beneath objects or materials that inhibit the use of previous monitoring wells. The tensiometer includes a porous cup, a pressure transducer (with an attached gasket device), an adaptive chamber, at least one outer guide tube which allows access to the desired horizontal position, a transducer wire, a data logger and preferably an inner guide tube and a specialized joint which provides pressure on the inner guide tube to maintain the seal between the gasket of the transducer and the adaptive chamber.

  2. Looking back at Love Canal

    SciTech Connect

    Deegan, J. Jr.

    1987-05-01

    In the first part of this series (ES and T, April 1987, pp. 328-31) it was pointed out that the methods and conclusions of EPA's Love Canal Study were the subject of some controversy in the environmental community. Others defended the agency's approaches and methods. Part 2 makes no attempt to resolve the controversy; its purpose is to present the results and conclusions of the Love Canal.

  3. Free vibrations of thin-walled semicircular graphite-epoxy composite frames

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Noor, Ahmed K.; Peters, Jeanne M.

    1990-01-01

    A detailed study is made of the effects of variations in lamination and material parameters of thin walled composite frames on their vibrational characteristics. The structures considered are semicircular thin walled frames with I and J sections. The flanges and webs of the frames are modeled by using 2-D shell and plate finite elements. A mixed formulation is used with the fundamental unknowns consisting of both the generalized displacements and stress resultants in the frame. The frequencies and modes predicted by the 2-D finite element model are compared with those obtained from experiments, as well as with the predictions of a non-dimensional thin walled beam finite element model. A detailed study is made of the sensitivity of the vibrational response to variations in the fiber orientation, material properties of the individual layers, and boundary conditions.

  4. The Suez Canal as a habitat and pathway for marine algae and seagrasses

    NASA Astrophysics Data System (ADS)

    Aleem, A. A.

    The Suez Canal supports a diversified benthic algal flora; 133 species of benthic algae are now known from the Canal, as compared with only 24 in 1924. The vertical and horizontal distribution of algae is considered in relation to hydrographic factors. The algae display zonation and 3-4 algal belts are distinguished on the Canal banks on buoys and pier supports. Associated fauna include Balanus amphitrite and Brachidontes variabilis, together with various hydroids, sponges, ascidians, asteroids, ophiuroids and crustaceans. Merceriella enigmatica thrives well in brackish water habitats. The algal flora in the Bitter Lakes resembles that in the Red Sea. The number of Red Sea species decreases from Suez to Port Said in the littoral zone. On the other hand, bottom algae predominantly belong to Red Sea flora. Thirty of the species of algae found belong to the Indo-Pacific flora; half of these are new records to the Canal. Several of these Indo-Pacific algae have recently become established in the Eastern Mediterranean, whereas only two of the Mediterranean macro-algal flora (viz. Caulerpa prolifera and Halopteris scoparia) have been found in the Gulf of Suez. Two seagrasses, Halopia ovalis and Thalassia hemprichii, are recorded for the first time in the Canal. Only Halophila stipulacea has found its way into the Mediterranean via the Suez Canal, but none of the Mediterranean seagrasses is found either in the Canal or in the Red Sea.

  5. 11. VIEW OF HORIZONTAL MIXER (GedgeGray Co., Lockland, Ohio), LOCATED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. VIEW OF HORIZONTAL MIXER (Gedge-Gray Co., Lockland, Ohio), LOCATED IN THE BASEMENT, MIXED ANIMAL FEED TO ORDER. THE WATER-POWERED MIXER WAS SUPERSEDED BY TWO ELECTRIC-POWERED VERTICAL MIXERS, ADDED IN THE 1940S. Photographer: Louise Taft Cawood, July 1986 - Alexander's Grist Mill, Lock 37 on Ohio & Erie Canal, South of Cleveland, Valley View, Cuyahoga County, OH

  6. Stratospheric aerosols in the intertropical convergence zone, Panama Canal zone

    NASA Technical Reports Server (NTRS)

    Farlow, N. H.; Ferry, G. V.; Lem, H. Y.; Hayes, D. M.

    1979-01-01

    To investigate whether injection sources of the stratospheric aerosol layer could be detected in the tropical stratosphere, an examination of the aerosol vertical and horizontal size distribution around the Intertropical Convergence Zone (ITCZ) at the Panama Canal Zone was performed during the summer of 1977. By comparing these data with similar measurements in temperate and polar regions, it was hoped to discover variations in particle size that would indicate whether a young aerosol is forming and entering the stratosphere at the ITCZ; where the aerosol matures; and finally, where it reenters the troposphere. The methods used in the investigations and the results obtained from the analyses are described.

  7. Depolarization canals and interstellar turbulence

    NASA Astrophysics Data System (ADS)

    Fletcher, A.; Shukurov, A.

    Recent radio polarization observations have revealed a plethora of unexpected features in the polarized Galactic radio background that arise from propagation effects in the random (turbulent) interstellar medium. The canals are especially striking among them, a random network of very dark, narrow regions clearly visible in many directions against a bright polarized Galactic synchrotron background. There are no obvious physical structures in the ISM that may have caused the canals, and so they have been called Faraday ghosts. They evidently carry information about interstellar turbulence but only now is it becoming clear how this information can be extracted. Two theories for the origin of the canals have been proposed; both attribute the canals to Faraday rotation, but one invokes strong gradients in Faraday rotation in the sky plane (specifically, in a foreground Faraday screen) and the other only relies on line-of-sight effects (differential Faraday rotation). In this review we discuss the physical nature of the canals and how they can be used to explore statistical properties of interstellar turbulence. This opens studies of magnetized interstellar turbulence to new methods of analysis, such as contour statistics and related techniques of computational geometry and topology. In particular, we can hope to measure such elusive quantities as the Taylor microscale and the effective magnetic Reynolds number of interstellar MHD turbulence.

  8. Horizontal Cross Bracing Detail, Vertical Cross Bracing Detail, Horizontal Cross ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Horizontal Cross Bracing Detail, Vertical Cross Bracing Detail, Horizontal Cross Bracing Joint, Vertical Cross Bracing End Detail - Ceylon Covered Bridge, Limberlost Park, spanning Wabash River at County Road 900 South, Geneva, Adams County, IN

  9. Investigation of otolith responses using ground based vestibular research facility

    NASA Technical Reports Server (NTRS)

    Correia, Manning J.; TABARACCI

    1989-01-01

    The general goal was to examine tilt sensitivity of horizontal semicircular canal afferents. Computer programs were tested which controlled the short axis centrifuge at the Vestibular Research Facility, acquired action potentials and produced data reduction analyses including histograms and gain and phase calculations. A pre-amplifier was also developed for the acquisition of action potentials. The data were gathered that can be used to contribute toward the understanding of the tilt sensitivity of semicircular canal afferents in the unanesthetized gerbil preparation.

  10. Conventional Versus Digital Radiography in Detecting Root Canal Type in Maxillary Premolars: An in Vitro Study

    PubMed Central

    Moshfeghi, Mahkameh; Sajadi, Soodabeh Sadat; Sajadi, Sepideh; Shahbazian, Majid

    2013-01-01

    Objective: Successful endodontic therapy depends on adequate mechanical and chemical debridement of the canal which requires knowledge of the canal morphology. Conventional radiography has been used to evaluate the canal type; however, direct digital radiography has recently been practiced for this purpose due to the shortcomings of conventional radiography. The aim of the present study was to compare the accuracy of digital and conventional radiography taken at 0° and 30° angles in the diagnosis of the canal type of extracted maxillary premolars. Materials and Methods: This diagnostic study was performed on 90 extracted maxillary premolars. Conventional and digital radiographies were taken of all teeth at 0° and 30° horizontal angles. The images were assessed by an oral and maxillofacial radiologist. The clearing technique was used as the gold standard. The canal type was determined using Weine classification. The agreement between each one of the 4 radiographic modalities and gold standard was determined by kappa statistics. Results: The kappa values for the agreement of parallel conventional, 30° conventional, parallel digital and 30° digital modalities with the clearing technique were 0.059, 0.215, 0.043 and 0.391, respectively. Parallel modalities were unable to determine the tooth canal type. Radiographic images taken at 30° significantly determined the canal type, although only a poor level of agreement was noted between the two modalities and the clearing technique. Conclusion: All modalities had limited value to determine the root canal type in maxillary premolars. However, direct digital imaging taken at 30° angle showed the highest accuracy for canal type assessment. PMID:23724205

  11. Corinth Canal, Greece

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The Isthmus of Corinth has played a very important role in the history of Greece. It is the only land bridge between the country's north (Attica) and south (Peloponnese). It is a 6 km wide tongue of land separating the Gulf of Corinth from the Saronic Sea. Populations, armies and commodities have got to move through it. In the 6th century BCE, the Greeks built the Diolkos, a 10 meter-wide stone roadway to pull ships across the Isthmus on wooden cylinders and wheeled vehicles. In 1882, a canal was started and completed 11 years later. It is 6343 meters long, 25 meters wide, and 8 meters deep.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 25.3 by 37.7 kilometers (15.7 by 23.4 miles) Location: 37.9 degrees North latitude, 23 degrees East longitude

  12. Ship canals and aquatic ecosystems

    USGS Publications Warehouse

    Aron, William I.; Smith, Stanford H.

    1971-01-01

    Through a combination of ecosystem homeostasis and the perversity of man and nature, oftentimes the significant biological changes effected by environmental modifications are not detected until long after the initial change has taken place. The immediate impact, which may range from the spectacular to the undetectable, is a deceptive measure of the long-term and often more important changes in the ecosystem. Two major engineering achievements illustrate this premise: (i) construction of the Erie Canal, which provided access from the Atlantic Ocean to the Great Lakes, and the Welland Canal, which bypasses the block between Lakes Ontario and Erie created by Niagara Falls (Fig. 1), and (ii) construction of the Suez Canal between the Red Sea and the Mediterranean Sea.

  13. 32. VIEW OF TWIN FALLS MAIN CANAL FROM VICINITY OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. VIEW OF TWIN FALLS MAIN CANAL FROM VICINITY OF PROPOSED POWER CANAL, LOOKING UPSTREAM. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  14. 23. VIEW OF PREEXISTING LINNIE CANAL COURT PEDESTRIAN BRIDGE OVER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. VIEW OF PRE-EXISTING LINNIE CANAL COURT PEDESTRIAN BRIDGE OVER EASTERN CANAL, LOOKING SOUTH FROM THE EAST SIDE OF EASTERN CANAL - Venice Canals, Community of Venice, Los Angeles, Los Angeles County, CA

  15. Pathologic diagnosis of central centrifugal cicatricial alopecia on horizontal sections.

    PubMed

    Miteva, Mariya; Tosti, Antonella

    2014-11-01

    The pathologic findings in Central Centrifugal Cicatricial Alopecia (CCCA) have not been studied systematically in horizontal sections. Our objective was to establish the pathologic features, and their frequency in horizontal sections of scalp biopsies obtained from patients with clinically and histologically proven CCCA. Serial horizontal sections of 51 cases were evaluated retrospectively. All biopsies were assessed at 4 levels and at least on 24 horizontal sections. The most common pathologic findings were follicular miniaturization (81% of the cases); premature desquamation of the inner root sheath (96%), focal preservation of the sebaceous glands (94%), which in most of these cases appeared as surrounding "in a hug" an intact vellus follicle; compound follicular structures with perifollicular fibrosis and/or inflammation (89%), lamellar hyperkeratosis/parakeratosis in the hair canal (79%), absent or mild inflammation (77%), and naked hair shafts (68%). Horizontal sections are useful in CCCA to identify early or focal disease and to provide the clinician with better information on the presence of follicular miniaturization, inflammation, and scarring, which can be used to tailor the treatment to the individual patient.

  16. Dentine removal in the coronal portion of root canals following two preparation techniques.

    PubMed

    Plotino, G; Grande, N M; Falanga, A; Di Giuseppe, I L; Lamorgese, V; Somma, F

    2007-11-01

    To measure the root canal area and the reduction of the mesial and buccal/lingual wall thickness at the level of the coronal interference in mesial roots of mandibular molars after instrumentation with a crown-down or a simultaneous root canal preparation technique. Twenty mesial roots of first mandibular molars with a moderate root canal curvature were embedded in resin and sectioned horizontally at the level of the coronal interference, using a modification of the Bramante technique. After scanning and processing, the sections were reassembled. One root canal of each root was prepared using ProTaper instruments, while Mtwo instruments were used in the other root canal of the same mesial root. After scanning and processing, the data obtained were analysed for two parameters: changes in root canal area after instrumentation (Delta A) and reduction of the mesial and buccal/lingual wall thickness (Delta T). The data were subjected to Student's t-tests for statistical analysis at a significance level of P < 0.05. No statistically significant differences were found between the two groups with respect to the changes in the areas (Delta A) at the level considered (P = 0.410). No statistically significant differences were noticed between the two groups for dentine thickness (Delta T) of both the mesial wall (P = 0.077) and the buccal or lingual wall (P = 0.171). There was no difference between the ProTaper and Mtwo groups for the amount of dentine removed.

  17. Dicyclic horizontal symmetries

    NASA Astrophysics Data System (ADS)

    Kong, Otto Cho Wing

    In the very successful standard theory of particle physics, the occurrence of repeated quark and lepton flavors, and especially their peculiar mass spectrum, can be accommodated parametrically but is largely unexplained. The present dissertation is an investigation into dicyclic horizontal symmetries as a theory addressing this elusive problem of flavor, as well as some other related issues in particle physics. A horizontal symmetry is a supplement to the perspective based on the experimentally well-established standard model, and its (supersymmetric) unification theories. Dicyclic groups are a special class of discrete non- abelian groups. The most pressing part of the flavor problem in the standard model is the existence of three families of (fermionic) matter and the unnaturally large hierarchy among the parameters describing their masses and mixing. In particular, the top quark is singled out as the only fermion having a natural mass at electroweak breaking scale. While bottom and tau masses may be suppressed by the Higgs vacuum expectation value, the small masses of the other two families beg an explanation. The supersymmetric counterpart of the problem is the need for a high degree of degeneracy especially among the squarks of the lighter two families. We first analyze the phenomenologically-viable quark and squark mass matrix textures using a simple algebraic method, paying particular attention to a 2 + 1 family structure. These serve as inputs for our model building exercises. We next illustrate how the various theoretical and phenomenological constraints single out a gauged dicyclic group as the most appealing candidate for a horizontal symmetry and discuss systematically our major model building strategies. A few models obtained along this line are then presented. These include a supersymmetric SU(5) /otimes Q12 /otimes U(1) model that successfully produces a phenomenologically-viable mass matrix texture pattern for the quarks and squarks.

  18. Measurement of the percentage of root filling in oval-shaped canals obturated with Thermafil Obturators and Beefill 2in1: In vitro study

    PubMed Central

    Collado-Castellanos, Nicolás; Alegre-Domingo, Teresa; Dolz-Solsona, María; Faus-Matoses, Vicente

    2015-01-01

    Background The aim of the study was to measure the percentage of root canal fillings in long oval canals obturated with thermoplasticized gutta-percha techniques, Beefill 2in1® and Thermafil Obturators®. Material and Methods Fifty four mandibular incisors were selected after bucco-lingual and mesio-distal radiographs showed at 5 mm from apex an internal long:short diameter ≥2. Teeth were instrumented with Protaper Universal and divided in two groups of 27. Group 1 was obturated with Thermafil Obturators® and group 2 with Beefill 2in1®. Two horizontal sections were cut at 5 and 7 mm from the apex and photographed in a stereo-microscope. The total area of the canal and filled canal in cross-sections were measured with AutoCad and the percentages of gutta-percha-sealer and voids in the canal were obtained. Results Both systems achieved high percentage of filled canal, Thermafil 96.8% and Beefill 2in1 98.9%. The percentages of voids in both groups were very low. No significant differences were found between the two groups . The percentage obtained at 5 and 7 mm from the apex in both groups showed no significant difference. Conclusions The percentages of filled canal (gutta-percha-sealer) were high and these two thermoplasticized techniques are suitable for long oval canals obturation. Key words:Long oval canal, oval canal, thermoplasticized obturation. PMID:26155350

  19. Assessing morphology and function of the semicircular duct system: introducing new in-situ visualization and software toolbox

    PubMed Central

    David, R.; Stoessel, A.; Berthoz, A.; Spoor, F.; Bennequin, D.

    2016-01-01

    The semicircular duct system is part of the sensory organ of balance and essential for navigation and spatial awareness in vertebrates. Its function in detecting head rotations has been modelled with increasing sophistication, but the biomechanics of actual semicircular duct systems has rarely been analyzed, foremost because the fragile membranous structures in the inner ear are hard to visualize undistorted and in full. Here we present a new, easy-to-apply and non-invasive method for three-dimensional in-situ visualization and quantification of the semicircular duct system, using X-ray micro tomography and tissue staining with phosphotungstic acid. Moreover, we introduce Ariadne, a software toolbox which provides comprehensive and improved morphological and functional analysis of any visualized duct system. We demonstrate the potential of these methods by presenting results for the duct system of humans, the squirrel monkey and the rhesus macaque, making comparisons with past results from neurophysiological, oculometric and biomechanical studies. Ariadne is freely available at http://www.earbank.org. PMID:27604473

  20. [Anatomical variations in the hypoglossal canal].

    PubMed

    De Francisco, M; Lemos, J L; Liberti, E A; Adamo, J; Jácomo, A L; Matson, E

    1990-01-01

    In this paper, 492 human dried skulls grouped according to sex and race (White and no White) were examined and the presence of a double hypoglossal canal was observed in 97 skulls. The statistical analysis allowed us to conclude that no significative difference exists in race X canal type; sex X canal type; race X side and sex X side interations.

  1. Sonic instruments in root canal therapy.

    PubMed

    Waplington, M; Lumley, P J; Walmsley, A D

    1995-10-01

    Although hand instrumentation is considered the most acceptable method of preparing root canals, sonic instruments may be useful additions to the endodontic armamentarium. Sonic instrumentation may be incorporated as an adjunct to traditional techniques for shaping the root canal. The use of such instruments may assist the practitioner during root canal treatment in general practice.

  2. Spinal canal narrowing during simulated frontal impact.

    PubMed

    Ivancic, Paul C; Panjabi, Manohar M; Tominaga, Yasuhiro; Pearson, Adam M; Elena Gimenez, S; Maak, Travis G

    2006-06-01

    Between 23 and 70% of occupants involved in frontal impacts sustain cervical spine injuries, many with neurological involvement. It has been hypothesized that cervical spinal cord compression and injury may explain the variable neurological profile described by frontal impact victims. The goals of the present study, using a biofidelic whole cervical spine model with muscle force replication, were to quantify canal pinch diameter (CPD) narrowing during frontal impact and to evaluate the potential for cord compression. The biofidelic model and a sled apparatus were used to simulate frontal impacts at 4, 6, 8, and 10 g horizontal accelerations of the T1 vertebra. The CPD was measured in the intact specimen in the neutral posture (neutral posture CPD), under static sagittal pure moments of 1.5 Nm (pre-impact CPD), during dynamic frontal impact (dynamic impact CPD), and again under static pure moments following each impact (post-impact CPD). Frontal impact caused significant (P<0.05) dynamic CPD narrowing at C0-dens, C2-C3, and C6-C7. The narrowest dynamic CPD was observed at C0-dens during the 10 g impact and was 25.9% narrower than the corresponding neutral posture CPD. Interpretation of the present results indicate that the neurological symptomatology reported by frontal impact victims is most likely not due to cervical spinal cord compression. Cord compression due to residual spinal instability is also not likely.

  3. Semicircular bend testing with split Hopkinson pressure bar for measuring dynamic tensile strength of brittle solids

    NASA Astrophysics Data System (ADS)

    Dai, F.; Xia, K.; Luo, S. N.

    2008-12-01

    We propose and validate an indirect tensile testing method to measure the dynamic tensile strength of rocks and other brittle solids: semicircular bend (SCB) testing with a modified split Hopkinson pressure bar (SHPB) system. A strain gauge is mounted near the failure spot on the specimen to determine the rupture time. The momentum trap technique is utilized to ensure single pulse loading for postmortem examination. Tests without and with pulse shaping are conducted on rock specimens. The evolution of tensile stress at the failure spot is determined via dynamic and quasistatic finite element analyses with the dynamic loads measured from SHPB as inputs. Given properly shaped incident pulse, far-field dynamic force balance is achieved and the peak of the loading matches in time with the rupture onset of the specimen. In addition, the dynamic tensile stress history at the failure spot obtained from the full dynamic finite element analysis agrees with the quasistatic analysis. The opposite occurs for the test without pulse shaping. These results demonstrate that when the far-field dynamic force balance is satisfied, the inertial effects associated with stress wave loading are minimized and thus one can apply the simple quasistatic analysis to obtain the tensile strength in the SCB-SHPB testing. This method provides a useful and cost effective way to measure indirectly the dynamic tensile strength of rocks and other brittle materials.

  4. SEMICIRCULAR-LIKE SECONDARY FLARE RIBBONS ASSOCIATED WITH A FAILED ERUPTION

    SciTech Connect

    Zheng, R.; Korsós, M. B.; Erdélyi, R. E-mail: robertus@sheffield.ac.uk

    2015-08-10

    Flare ribbons (FRs) are one of the most apparent signatures of solar flares and have been treated as an indicator of magnetic reconnection. Drawing upon the observations from the Solar Dynamics Observatory, we present semicircular-like secondary FRs (SFRs) of a C2.3 flare on 2013 June 19. Before the flare eruption, two bipoles in this core region subsequently emerged. Due to the interaction between the two bipoles, a tether-cutting eruption took place in the core region. The SFRs, surrounding the core region nearly simultaneously with the flare onset, were much weaker than the two normal FRs. Two ends of the SFRs experienced a separation and extension movement, but the middle part of the SFRs hardly expanded outward. We find SFRs are closely associated with the footpoint brightenings of some small loops around the core region. The eruption was confined by transequatorial loops (TLs), which resulted in the plasma material falling in the north end of the TLs and remote brightenings showing up in the south end of the TLs. The disappearance of the faint (filament) material during the emergence of the SFRs could indicate another eruption. We conclude that two or more magnetic reconnections are involved in this event and propose that SFRs consisting of a small part of true FRs resulted from the second magnetic reconnection and bright footpoints of loop clusters likely heated by the main flare.

  5. Erie Canal Technology: Stump Pullers

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2013-01-01

    Many years ago I saw a picture of a huge set of wheels that was used to remove tree stumps during the construction of the Erie Canal (1817-1825) and was intrigued by its use of leverage, mechanical advantage, and torque. Figure 1 is a scale model of the device based on my memory of the (lost) picture and published accounts.

  6. Erie Canal Technology: Stump Pullers

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2013-10-01

    Many years ago I saw a picture of a huge set of wheels that was used to remove tree stumps during the construction of the Erie Canal (1817-1825) and was intrigued by its use of leverage, mechanical advantage, and torque. Figure 1 is a scale model of the device based on my memory of the (lost) picture and published accounts.

  7. The analysis of ear canals

    NASA Astrophysics Data System (ADS)

    Ou, Gen

    In this thesis complex 3-D ear canal finite element models are simplified using transfer matrices to 1-D models. This simplification allows analysis on the sound propagation in the ear, which results in potentially using a non-invasive probe to determine the acoustical properties of the ear.

  8. Erie Canal Technology: Stump Pullers

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2013-01-01

    Many years ago I saw a picture of a huge set of wheels that was used to remove tree stumps during the construction of the Erie Canal (1817-1825) and was intrigued by its use of leverage, mechanical advantage, and torque. Figure 1 is a scale model of the device based on my memory of the (lost) picture and published accounts.

  9. [Endodontic microbiology: antimicrobial canal medications].

    PubMed

    Seltzer, S; Farber, P A

    1989-06-01

    Medicaments used for reducing or eliminating microorganisms from infected root canals include: irrigating solutions, such as sodium hypochlorite, urea peroxide and hydrogen peroxide, chloramine, iodine-potassium-iodide solution, and chlorhexidine solution. In addition, various intracanal drugs, such as calcium hydroxide and antibiotics, are in use. The characteristics of these drugs are discussed.

  10. Horizontal baffle for nuclear reactors

    DOEpatents

    Rylatt, John A.

    1978-01-01

    A horizontal baffle disposed in the annulus defined between the core barrel and the thermal liner of a nuclear reactor thereby physically separating the outlet region of the core from the annular area below the horizontal baffle. The horizontal baffle prevents hot coolant that has passed through the reactor core from thermally damaging apparatus located in the annulus below the horizontal baffle by utilizing the thermally induced bowing of the horizontal baffle to enhance sealing while accommodating lateral motion of the baffle base plate.

  11. Granular slumping on a horizontal surface

    NASA Astrophysics Data System (ADS)

    Lajeunesse, E.; Monnier, J. B.; Homsy, G. M.

    2005-10-01

    We report the results of an experimental investigation of the flow induced by the collapse of a column of granular material (glass beads of diameter d) over a horizontal surface. Two different setups are used, namely, a rectangular channel and a semicircular tube, allowing us to compare two-dimensional and axisymmetric flows, with particular focus on the internal flow structure. In both geometries the flow dynamics and the deposit morphologies are observed to depend primarily on the initial aspect ratio of the granular column a =Hi/Li, where Hi is the height of the initial granular column and Li its length along the flow direction. Two distinct regimes are observed depending on a: an avalanche of the column flanks producing truncated deposits for small a and a column free fall leading to conical deposits for large a. In both geometries the characteristic time scale is the free fall of the granular column τc=√Hi/g . The flow initiated by Coulomb-like failure never involves the whole granular heap but remains localized in a surface layer whose size and shape depend on a and vary in both space and time. Except in the vicinity of the pile foot where the flow is pluglike, velocity profiles measured at the side wall are identical to those commonly observed in steady granular surface flows: the velocity varies linearly with depth in the flowing layer and decreases exponentially with depth in the static layer. Moreover, the shear rate is constant, γ˙=0.3√g /d , independent of the initial aspect ratio, the flow geometry, position along the heap, or time. Despite the rather complex flow dynamics, the scaled deposit height Hf/Li and runout distance ΔL /Li both exhibit simple power laws whose exponents depend on a and on the flow geometry. We show that the physical origin of these power laws can be understood on the basis of a dynamic balance between acceleration, pressure gradient, and friction forces at the foot of the granular pile. Two asymptotic behaviors can be

  12. [Tonic conjugated action of receptor-receptor fibers and of the efferent vestibular system on the spontaneous afferene activity of a semicircular canal in the frog].

    PubMed

    Gribenski, A; Caston, J

    1976-01-01

    In the frog, the joint action of non-afferent vestibular systems [i.e. the efferent vestibular system and the receptor-receptor fibre system] on the afferent vestibular activity is null or very small. The receptor-receptor fibre system being inhibitory, it seems that the efferent vestibular system as a whole is facilitatory, which agrees with previous results.

  13. The Amplitude and Inactivation Properties of the Delayed Potassium Currents Are Regulated by Protein Kinase Activity in Hair Cells of the Frog Semicircular Canals

    PubMed Central

    Martini, Marta; Canella, Rita; Fesce, Riccardo; Rossi, Maria Lisa

    2013-01-01

    In hair cells dissected from the frog crista ampullaris, the combination of a calcium-dependent (IKCa) and a purely voltage-dependent component (IKV) gives rise to the delayed potassium current complex (IKD). These currents have been recently reported to display slow depolarization-induced inactivation and biphasic inactivation removal by hyperpolarization. The amplitude and inactivation kinetics of both IKCa and IKV are drastically modulated by a previously unrecognized mechanism of protein phosphorylation (sensitive to kinase inhibitors H89 and KT5823), which does not interfere with the transient potassium current (IA) or the calcium current (ICa). IKD amplitude was stable in cells patched with pipettes containing 8 mM ATP or under perforated-patch; under these conditions, a 10 min treatment with 10 µM H89 or 1–10 µM KT5823 reduced IKD amplitude by a mean of 67% at +40 mV. Similarly affected was the isolated IKV component (ICa blocked with Cd2+). Thus, a large potassium conductance can be activated by depolarization, but it is made available to the cell to a variable extent that depends on membrane potential and protein kinase activity. The total gKD ranged 4.6–44.0 nS in control cells, according to the level of steady-state inactivation, and was reduced to 1.4–2.7 nS after protein kinase inhibition. When sinusoidal membrane potential changes in the −70/−10 mV range were applied, to mimic receptor response to hair bundle deflection, IKD proved the main current dynamically activated and the only one regulated by PK: H89 decreased the total outward charge during each cycle by 60%. Phosphorylation appears to control both the amount of IKCa and IKV conductance activated by depolarization and the fraction thereof which can be rescued by removal of inactivation. The balance between the depolarizing transduction current and the repolarizing potassium current, and eventually the transmitter release at the cytoneural junction, are therefore modulated by a phosphorylation-mediated process. PMID:23844092

  14. Otogenic cerebellar abscess due to purulent labyrinthitis and defect of the superior semicircular canal and its propagation through the endolymphatic sac.

    PubMed

    Durisin, Martin; Stöver, Timo; Leinung, Martin; Mangold, Andreas; Rittierodt, Marion; Lenarz, Thomas

    2007-08-01

    The otogenic cerebellar abscess still is one of the most dangerous complications of otitis media and implicates a high risk of mortality. Early diagnosis and therapy are decisive factors for the chances of rehabilitation. Radiologic imaging (CT/MRI) plays an important role. A broad-spectrum antibiotic according to antibiogram is indispensable. The type of surgical intervention depends on the cause and localization of the abscess. In this case the cerebellar abscess was a complication resulting from labyrinthitis, which was propagated through the endolymphatic duct and sac to the posterior fossa dura. Consequently, it could be cured ultimately only after petrosectomy and abscess drainage toward the mastoid cavity. It is mandatory to completely sanitize the infection surgically in order to avoid lethal complication especially in case of a delayed clinical course or recurrent symptoms of labyrinth involvement. Close interdisciplinary collaboration between ORL, neurosurgery and neuroradiology is desirable for successful therapy.

  15. HORIZONTAL BOILING REACTOR SYSTEM

    DOEpatents

    Treshow, M.

    1958-11-18

    Reactors of the boiling water type are described wherein water serves both as the moderator and coolant. The reactor system consists essentially of a horizontal pressure vessel divided into two compartments by a weir, a thermal neutronic reactor core having vertical coolant passages and designed to use water as a moderator-coolant posltioned in one compartment, means for removing live steam from the other compartment and means for conveying feed-water and water from the steam compartment to the reactor compartment. The system further includes auxiliary apparatus to utilize the steam for driving a turbine and returning the condensate to the feed-water inlet of the reactor. The entire system is designed so that the reactor is self-regulating and has self-limiting power and self-limiting pressure features.

  16. Algae control for hydrogeneration canals

    SciTech Connect

    Grahovac, P.

    1997-02-16

    The purpose of this Cooperative Research and Development Agreement (CRADA) was to assess and develop control practices for nuisance algae growth in power canal that delivers water to hydro-generation facilities. This growth results in expenditures related not only to lost generation but also labor and materials costs associated with implementing remediation procedures. On an industry-wide basis these costs associated with nuisance algal growth are estimated to be several million dollars per year.

  17. Horizontal microscopy in square capillaries

    NASA Astrophysics Data System (ADS)

    Moroz, Pavel E.

    1992-07-01

    Intracellular protoplasmic movements may, due to gravity, have a vertical component greater or different from the horizontal one. This makes horizontal microscopy indispensable in the search for the cellular sensor of gravity. The possibility of the latter being a cell organelle assigns special significance to high-resolution microscopy. A horizontal suction device for picking up a cell and its high-resolution horizontal microscopy in a rectangular capillary may be helpful for detection of gravity-related shifts of cellular organelles in vivo.

  18. Almost horizontal turbulence

    NASA Astrophysics Data System (ADS)

    Kolmogorov, A. N.

    2004-04-01

    The paper is published without modifications. Kolmogorov's manuscript was apparently prepared during his participation in one of expeditions of the ship "D. Mendeleev" to the Atlantic Ocean (1969) or in a circumnavigation of the world (1971) organized by the Institute for Oceanology led at the time by A.S. Monin. As Kolmogorov himself wrote, the choice of the topic was stimulated by observations concerning "...meanders with horizontal sizes of hundreds of kilometers on a flow involving a layer of hundreds of meters, with subsequent disintegration of these meanders into vortices gradually decreasing in size to several kilometers." In modern terminology, the paper is devoted to the problem of intensive mixing in pycnoclines, that is, thin layers of stratified fluid, caused by internal waves whose frequencies are less than the Brent-Väisälä frequency. Here I would like to note two circumstances. The first is the scientific insight characteristic for Kolmogorov; this very approach was later reflected in numerous publications (see, for instance, the monograph by V.S. Modevich, V.I. Nikulin, and A.G. Stetsenko "Dynamics of internal mixing in a stratified medium," Institute for Hydromechanics, Academy of Sciences of Ukraine, Naukova Dumka, Kiev 1988). The second, the more significant in my opinion, is the genuine intellectual curiosity and breadth of thought of this great thinker, who studied not only the most abstract mathematical constructions but also got his head out of the clouds with great interest to solve concrete applied problems.

  19. Inferring Horizontal Gene Transfer

    PubMed Central

    Lassalle, Florent; Dessimoz, Christophe

    2015-01-01

    Horizontal or Lateral Gene Transfer (HGT or LGT) is the transmission of portions of genomic DNA between organisms through a process decoupled from vertical inheritance. In the presence of HGT events, different fragments of the genome are the result of different evolutionary histories. This can therefore complicate the investigations of evolutionary relatedness of lineages and species. Also, as HGT can bring into genomes radically different genotypes from distant lineages, or even new genes bearing new functions, it is a major source of phenotypic innovation and a mechanism of niche adaptation. For example, of particular relevance to human health is the lateral transfer of antibiotic resistance and pathogenicity determinants, leading to the emergence of pathogenic lineages [1]. Computational identification of HGT events relies upon the investigation of sequence composition or evolutionary history of genes. Sequence composition-based ("parametric") methods search for deviations from the genomic average, whereas evolutionary history-based ("phylogenetic") approaches identify genes whose evolutionary history significantly differs from that of the host species. The evaluation and benchmarking of HGT inference methods typically rely upon simulated genomes, for which the true history is known. On real data, different methods tend to infer different HGT events, and as a result it can be difficult to ascertain all but simple and clear-cut HGT events. PMID:26020646

  20. A DRBEM for steady infiltration from periodic semi-circular channels with two different types of roots distribution

    NASA Astrophysics Data System (ADS)

    Solekhudin, Imam; Sumardi

    2017-05-01

    In this study, problems involving steady Infiltration from periodic semicircular channels with root-water uptake function are considered. These problems are governed by Richards equation. This equation can be studied more conveniently by transforming the equation into a modified Helmholtz equation. In these problems, two different types of root-water uptake are considered. A dual reciprocity boundary element method (DRBEM) with a predictor-corrector scheme is used to solve the modified Helmholtz equation numerically. Using the solution obtained, numerical values of suction potential and root-water uptake function can be computed. In addition, amount of water absorbed by the different plant roots distribution can also be computed and compared.

  1. Characteristics of wax occlusion in the surgical repair of superior canal dehiscence in human temporal bone specimens

    PubMed Central

    Cheng, Yew Song; Kozin, Elliott D.; Remenschneider, Aaron K.; Nakajima, Hideko Heidi; Lee, Daniel J.

    2015-01-01

    Hypothesis Superior canal dehiscence (SCD) repair using surgical bone wax may result in variable outcomes if large wax volumes are applied. Background SCD is a disorder characterized by a pathologic defect in the bony labyrinth of the superior semicircular canal (SSC), resulting in vestibular and/or auditory symptoms. Repair of SCD using bone wax can provide symptomatic relief, but surgical outcomes are variable. These observations may be associated with the inconsistency in the position and extension of intralabyrinthine bone wax during surgical repair. Methods A pathological model of SCD was created using cadaveric human temporal bones and a microdrill. Defects in the arcuate eminence 0.5–3.5 mm in length were repaired using surgical occlusion with bone wax. The volume of wax used in the repair was quantified. The position of bone wax was evaluated by direct visualization and imaging (computed tomography [CT]). To visualize wax on CT, specimens were repaired using radiopaque wax. Results Exceedingly small volumes of bone wax (3.0–5.0 mm2) reliably occluded the canal lumen. Multiple wax applications resulted in extension into the common crus and ampulla. The length of this extension was related to the number of applications. Conclusions Repair of SCD with bone wax occludes the bony defect completely in most cases. Wax can extend along the lumen of the superior canal beyond the limits of the dehiscence to reach the sensory neuroepithelium of the vestibular end organs. Limiting the number of wax applications is essential to avoid inadvertent injury to the delicate neurosensory systems. PMID:26649609

  2. Understanding Horizontal Governance. Research Brief

    ERIC Educational Resources Information Center

    Ferguson, Daniel

    2009-01-01

    Horizontal governance is an umbrella term that covers a range of approaches to policy development, service delivery issues, and management practices. A horizontal initiative may take place across levels of government, across boundaries between units of a single department or agency or among multiple departments or agencies, or across public,…

  3. Management of Six Root Canals in Mandibular First Molar

    PubMed Central

    Gomes, Fabio de Almeida; Sousa, Bruno Carvalho

    2015-01-01

    Success in root canal treatment is achieved after thorough cleaning, shaping, and obturation of the root canal system. This clinical case describes conventional root canal treatment of an unusual mandibular first molar with six root canals. The prognosis for endodontic treatment in teeth with abnormal morphology is unfavorable if the clinician fails to recognize extra root canals. PMID:25685156

  4. 179. Photocopy of Photograph, Twin Falls Canal Company, Bisbee Photo, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    179. Photocopy of Photograph, Twin Falls Canal Company, Bisbee Photo, September, 1912. Photographer unknown. VIEW OF LOW LINE CANAL, TWIN FALLS COUNTY; VIEW OF LOW LINE CANAL IN PETE LINK'S FIELD. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  5. Mechanized instrumentation of root canals oscillating systems.

    PubMed

    Leonardo, Renato de Toledo; Puente, Carlos Garcia; Jaime, Alejandro; Jent, Carol

    2013-01-01

    Cleaning and shaping are important steps in the root canal treatment. Despite the technological advances in endodontics, K and Hedstroen files are still widely used. In an attempt to be more effective in preparing the root canals, faster and more cutting efficient kinematic, alloys and design alternatives utilizing mechanically oscillating or rotary files are proposed. Even with all these technological innovating alternatives, the preparation of root canals remains a challenge.

  6. Effect of photoactivated disinfection on bond strength of root canal filling.

    PubMed

    Ok, Evren; Ertas, Huseyin; Saygili, Gokhan; Gok, Tuba

    2013-11-01

    The aim of this in vitro study was to assess and compare the effect of photoactivated disinfection (PAD) on the bond strength of root canal sealers to human root canal dentin using the push-out test. Fifteen extracted human mandibular premolar teeth with single and straight roots were used. After the clinical crowns were removed from the cementoenamel junction, root canals were prepared with the ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) rotary system to the size of the F3 file. The smear layer of the roots was removed using 17% EDTA followed by 5.25% sodium hypochlorite (NaOCl) and distillate water. The roots were then randomly divided into 3 groups (n = 5) according to the final irrigation regimen. In group 1, PAD (FotoSan; CMS Dental, Copenhagen, Denmark) was applied to the root canals and light cured for 20 seconds. Group 2 was finally irrigated with a 2% solution of chlorhexidine gluconate, and group 3 served as the control group (NaOCl + EDTA). All the canals were then obturated with the lateral condensation technique using gutta-percha and AH Plus sealer (Dentsply Maillefer) sealer. One-millimeter-thick horizontal sections from the coronal and midthirds of each root (n: 5 × 4 = 20) were sliced for the push-out bond strength measurement. The data were converted to megapascals and statistically analyzed using 1-way analysis of variance and the post hoc Tukey test. There was no significant difference among the bond strength of PAD, chlorhexidine gluconate, and NaOCl (P > .05). We conclude that PAD does not adversely affect the bond strength of the AH Plus sealer to root canal dentin and that it can be used for the final disinfection of root canals. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  7. Long-Period Cultural Noise: The Panama Canal Seiche

    NASA Astrophysics Data System (ADS)

    McNamara, D. E.; Hutt, C. R.; Ringler, A.; Gee, L. S.

    2009-12-01

    Traditionally, the spectral composition of human generated or “cultural” seismic noise is dominated by short-period (SP) energy (<1s). In this study, we present evidence for long-period (LP) cultural noise (100-200s) at the USGS Global Seismographic Network (GSN) station CU.BCIP, located at the Smithsonian Tropical Research Institute (STRI) on Barro Colorado Island (BCI) in the Panama Canal. The LP seismic energy has a strong diurnal signal, with highest power during the daytime when traffic through the Panama Canal is the heaviest, ~1 ship every 10 minutes. The lowest power occurs during the late-night/early-morning hours, when container ship traffic slows to ~1 ship every hour. Spectral power observations are corroborated with data recorded by a water-level meter located approximately 80m from the seismic station, indicating that water waves are the primary source of the LP seismic signal. We show that the observed water waves are a “seiche” induced by the wakes of container ship traffic in the canal. As passing ships disturb the water surface, standing waves are induced by the summation of propagating waves, traveling in opposite directions, due to reflections off the opposite shorelines of the Panama Canal. Vertical harmonic motion results as gravity seeks to restore the horizontal surface of the body of water to a state of hydrostatic equilibrium. The longest natural-period of a seiche in an enclosed body of water is a function of basin depth and length and can be computed by a common oceanographic relationship, known as the Merian formula. For a reasonable range of Panama Canal dimensions in the vicinity of BCI, (depths from 15 to 30m and lengths from 700 to 1500m), the predicted dominant period of a seiche is between 100-200s, consistent with our seismic spectral power observations. Small rhythmic seiches are always present in disturbed enclosed bodies of water and are most often caused by either meteorological effects (wind and atmospheric pressure

  8. Love Canal: environmental and toxicological studies

    SciTech Connect

    Kim, C.S.

    1981-01-01

    The New York State Department of Health has been involved at the Love Canal since 1978. The State has carried out numerous environmental and toxicological studies. The major purposes for these studies were to define how Love Canal contaminants might be escaping into the environment at large, what paths contaminant migration might take, and what toxicological effects Love Canal chemicals might have individually and together. Although underground contaminant migration was hypothesized along swales and underground utility bedding, these mechanisms have been proven not to be operative except for some migration along the utility bedding under Frontier Avenue. In general no underground migration has occurred outside the confines of the three city blocks that contain the Love Canal referred to as the ''first ring''. Studies have been confused by apparent burial of waste materials in areas proximate but not directly connected to the Love Canal. Migration of Love Canal leachate has occurred through storm sewers. Love Canal contaminants have reached creeks to the north and the Niagara River to the south through storm sewer transport. In spite of finding 2, 3, 7, 8 tetrachlorodibenzoparadioxin (TCDD), toxicological studies in situ and through exposure to volatile components in Love Canal soils do not indicate unusual toxicity. Animal studies continue in an attempt to determine the teratogenic and fetotoxic potential of Love Canal chemicals under different routes of exposure.

  9. Numerical modelling of esker formation in semi-circular subglacial channels

    NASA Astrophysics Data System (ADS)

    Beaud, Flavien; Flowers, Gwenn E.; Venditti, Jeremy G.

    2017-04-01

    Eskers hold valuable information about past subglacial hydraulic conditions in their spatial organization, geometry, and sedimentary structures. The relations between hydraulic conditions and esker properties are nevertheless intricate as the formation of eskers has been mainly inferred from descriptive theories, about which a consensus has yet to be reached. Eskers are prevalent in areas of rigid bed and thin till cover and their formation is thought to be predominantly controlled by either water or sediment availability. In this study, we develop a 1-D numerical model of sediment transport in semi-circular bedrock-floored channels to explore the physical processes leading to esker formation. The model encompasses channel evolution by melt-opening created by the viscous heat dissipated as water flows, the creep closure of the ice walls, and changes in cross-sectional area due to sediment accumulation and removal. We find that a bottleneck in sediment transport close to the terminus is an inherent characteristic of subglacial channels. Creep closure is reduced as the ice thins towards the terminus and hydraulic potential gradients decline, thus reducing shear stresses. This bottleneck is accentuated when water discharge drops in a well established channel. We find the conditions most conducive to sediment deposition are low ice-surface slopes within several kilometres of the terminus and water discharge fluctuations over a few to several weeks. The model also produces shear stresses large enough to transport boulders under typical melt-season conditions. Our results thus suggest that incipient eskers form toward the end of the melt season, provided water input and sediment supply are sufficient. Overall these findings corroborate the theory that eskers are formed progressively during the waning stage of an ice sheet, although we suggest that eskers are a natural manifestation of the subglacial hydraulic system in the presence of an adequate trade-off between

  10. 5 CFR 315.601 - Appointment of former employees of the Canal Zone Merit System or Panama Canal Employment System.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Canal Zone Merit System or Panama Canal Employment System. 315.601 Section 315.601 Administrative... employees of the Canal Zone Merit System or Panama Canal Employment System. (a) Agency authority. This... Zone Merit System, which was in effect before March 31, 1982, or under the Panama Canal Employment...

  11. 5 CFR 315.601 - Appointment of former employees of the Canal Zone Merit System or Panama Canal Employment System.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Canal Zone Merit System or Panama Canal Employment System. 315.601 Section 315.601 Administrative... employees of the Canal Zone Merit System or Panama Canal Employment System. (a) Agency authority. This... Zone Merit System, which was in effect before March 31, 1982, or under the Panama Canal Employment...

  12. 5 CFR 315.601 - Appointment of former employees of the Canal Zone Merit System or Panama Canal Employment System.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Canal Zone Merit System or Panama Canal Employment System. 315.601 Section 315.601 Administrative... employees of the Canal Zone Merit System or Panama Canal Employment System. (a) Agency authority. This... Zone Merit System, which was in effect before March 31, 1982, or under the Panama Canal Employment...

  13. 5 CFR 315.601 - Appointment of former employees of the Canal Zone Merit System or Panama Canal Employment System.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Canal Zone Merit System or Panama Canal Employment System. 315.601 Section 315.601 Administrative... employees of the Canal Zone Merit System or Panama Canal Employment System. (a) Agency authority. This... Zone Merit System, which was in effect before March 31, 1982, or under the Panama Canal Employment...

  14. The suppression effect of a periodic surface with semicircular grooves on the high power microwave long pill-box window multipactor phenomenon

    NASA Astrophysics Data System (ADS)

    Zhang, Xue; Wang, Yong; Fan, Junjie; Zhong, Yong; Zhang, Rui

    2014-09-01

    To improve the transmitting power in an S-band klystron, a long pill-box window that has a disk with grooves with a semicircular cross section is theoretically investigated and simulated. A Monte-Carlo algorithm is used to track the secondary electron trajectories and analyze the multipactor scenario in the long pill-box window and on the grooved surface. Extending the height of the long-box window can decrease the normal electric field on the surface of the window disk, but the single surface multipactor still exists. It is confirmed that the window disk with periodic semicircular grooves can explicitly suppress the multipactor and predominantly depresses the local field enhancement and the bottom continuous multipactor. The difference between semicircular and sharp boundary grooves is clarified numerically and analytically.

  15. The suppression effect of a periodic surface with semicircular grooves on the high power microwave long pill-box window multipactor phenomenon

    SciTech Connect

    Zhang, Xue Wang, Yong; Fan, Junjie; Zhong, Yong; Zhang, Rui

    2014-09-15

    To improve the transmitting power in an S-band klystron, a long pill-box window that has a disk with grooves with a semicircular cross section is theoretically investigated and simulated. A Monte-Carlo algorithm is used to track the secondary electron trajectories and analyze the multipactor scenario in the long pill-box window and on the grooved surface. Extending the height of the long-box window can decrease the normal electric field on the surface of the window disk, but the single surface multipactor still exists. It is confirmed that the window disk with periodic semicircular grooves can explicitly suppress the multipactor and predominantly depresses the local field enhancement and the bottom continuous multipactor. The difference between semicircular and sharp boundary grooves is clarified numerically and analytically.

  16. Dundee Canal Industrial Historic District, Beginning at George Street in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Dundee Canal Industrial Historic District, Beginning at George Street in Passaic & extending north along Dundee Canal approximately 1.2 miles to Canal headgates opposite East Clifton Avenue in Clifton, Passaic, Passaic County, NJ

  17. 15. VIEW OF GAGE IRRIGATION CANAL NEAR HILLTOP DRIVE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. VIEW OF GAGE IRRIGATION CANAL NEAR HILLTOP DRIVE AND BARTON ROAD, SHOWING END OF SIPHON. CANAL FOLLOWS CONTOUR OF HILL UNDER DIRT ROAD - Gage Irrigation Canal, Running from Santa Ana River to Arlington Heights, Riverside, Riverside County, CA

  18. OBLIQUE VIEW OF NORTHWEST SIDE OF 2195 SOUTHWEST CANAL STREET, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OBLIQUE VIEW OF NORTHWEST SIDE OF 2195 SOUTHWEST CANAL STREET, VIEW TOWARDS SOUTHEAST - St. Lucie Canal, Lock No. 1, Attendant's Quarters, St. Lucie, Cross State Canal, Okeechobee Intracoastal Waterway, Stuart, Martin County, FL

  19. OBLIQUE VIEW OF SOUTHEAST SIDE OF 2195 SOUTHWEST CANAL STREET, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OBLIQUE VIEW OF SOUTHEAST SIDE OF 2195 SOUTHWEST CANAL STREET, VIEW TOWARDS NORTH - St. Lucie Canal, Lock No. 1, Attendant's Quarters, St. Lucie, Cross State Canal, Okeechobee Intracoastal Waterway, Stuart, Martin County, FL

  20. 2. General view of site from south side of canal, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. General view of site from south side of canal, showing south (Canal Street) side of structures; view to northeast. - Champion-International Paper Company, West bank of Spicket River at Canal Street, Lawrence, Essex County, MA

  1. 1. General view of site from head of canal, showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. General view of site from head of canal, showing south (Canal Street) side of structures; view to northwest. - Champion-International Paper Company, West bank of Spicket River at Canal Street, Lawrence, Essex County, MA

  2. 5. Division Gates of the Consolidated Canal, looking northeast. The ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Division Gates of the Consolidated Canal, looking northeast. The Tempe Canal heads here (left). Photographer: Mark Durben, February 1989. Source: SRPA - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

  3. 22. TWIN FALLS MAIN CANAL HEADWORKS WITH MILNER DAM IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. TWIN FALLS MAIN CANAL HEADWORKS WITH MILNER DAM IN DISTANCE; LOOKING EAST. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  4. 31. VIEW OF TWIN FALLS MAIN CANAL BRIDGE FROM DOWNSTREAM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. VIEW OF TWIN FALLS MAIN CANAL BRIDGE FROM DOWNSTREAM LOOKING UPSTREAM. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  5. 29. VIEW OF TWIN FALLS MAIN CANAL BRIDGE FROM UPSTREAM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. VIEW OF TWIN FALLS MAIN CANAL BRIDGE FROM UPSTREAM LOOKING DOWNSTREAM. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  6. 24. TWIN FALLS MAIN CANAL HEADWORKS, DOWNSTREAM LOOKING TOWARD THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. TWIN FALLS MAIN CANAL HEADWORKS, DOWNSTREAM LOOKING TOWARD THE EAST. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  7. 30. VIEW OF TWIN FALLS MAIN CANAL FROM BRIDGE LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. VIEW OF TWIN FALLS MAIN CANAL FROM BRIDGE LOOKING WEST DOWNSTREAM. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  8. 23. TWIN FALLS MAIN CANAL HEADWORKS WITH MILNER DAM IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. TWIN FALLS MAIN CANAL HEADWORKS WITH MILNER DAM IN DISTANCE; LOOKING NORTHEAST. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  9. 26. DETAIL OF HEADGATE HOIST MACHINERY, TWIN FALLS MAIN CANAL. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. DETAIL OF HEADGATE HOIST MACHINERY, TWIN FALLS MAIN CANAL. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  10. 3. August, 1971. VIEW ALONG CANAL SHOWING BORDER PATH AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. August, 1971. VIEW ALONG CANAL SHOWING BORDER PATH AND BRIDGE FOR INSPECTION - ABOUT ONE MILE FROM CANAL HEAD. - Hurricane Irrigation Canal, State Route 15 Vicinity, Hurricane, Washington County, UT

  11. 10. DETAIL, SOUTHEAST SPAN THROUGH CANAL, VIEW BLOCKED BY STEEL, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. DETAIL, SOUTHEAST SPAN THROUGH CANAL, VIEW BLOCKED BY STEEL, CLAD COUNTER WEIGHT, WATER SPAN RAISED OUT OF VIEW - Cape Cod Canal Lift Bridge, Spanning Cape Cod Canal, Buzzards Bay, Barnstable County, MA

  12. 11. 'Y' CONNECTOR TO PICACHO RESERVOIR ON MAIN CANAL. VIEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. 'Y' CONNECTOR TO PICACHO RESERVOIR ON MAIN CANAL. VIEW LOOKING WEST FROM MAIN CANAL - San Carlos Irrigation Project, Marin Canal, Amhurst-Hayden Dam to Picacho Reservoir, Coolidge, Pinal County, AZ

  13. Hydrographic survey of a south Florida canal using a hydrolite

    NASA Astrophysics Data System (ADS)

    Berber, M.; Wright, W.

    2017-02-01

    In this study, a hydrographic map of a South Florida canal is prepared using RTK GPS (Real Time Kinematic Global Positioning System) measurements combined with a hydrolite (single beam echo sounder). RTK GPS measurements are made using both single RTK and Network RTK systems. Digital sounding measurements taken by hydrolite are compared to manual lead line measurements. Single RTK and Network RTK results differed in the order of tenth of a foot accuracy for horizontal coordinates and for height measurements variations can go up to several tenths. Sounding results indicate a best-fit trend line with a slope of 0.993, and an R squared value of 0.972, demonstrating that hydrolite measurements and manually collected depths at this site are well correlated.

  14. Ultrasonography of the teat canal in cows and sheep.

    PubMed

    Franz, S; Hofmann-Parisot, M; Baumgartner, W; Windischbauer, G; Suchy, A; Bauder, B

    2001-07-28

    When the isolated teat of a cow was examined with an 8.5 MHz linear array transducer in a vertical plane, the teat canal appeared as a thin, white line, bordered on each side by parallel, thick, grey-black bands. In a horizontal plane a comparable image was obtained. In a sheep, images of comparable quality were obtained with a 12 MHz transducer. Histological studies of the tissues whose removal led to the disappearance of this characteristic ultrasonographic appearance showed that it was associated with the stratified keratinised squamous epithelium with distinct papillae. The content of keratin in the stratum corneum was apparently responsible for the bright zone; the stratum lucidum was not visible, and the surrounding dark, less echoic area was associated with the stratum granulosum. Doppler echography in live animals confirmed this designation. The outer layers of the teat wall were more echogenic.

  15. Root Canal Treatment of a Maxillary Second Premolar with Two Palatal Root Canals: A Case Report

    PubMed Central

    Golmohammadi, Maryam; Jafarzadeh, Hamid

    2016-01-01

    Accurate diagnosis of the root canal morphology and anatomy is essential for thorough shaping and cleaning of the entire root canal system and consequent successful treatment. This report describes a case of maxillary second premolar with two roots and three root canals (two mesial and distal palatal canals). The case report underlines the importance of complete knowledge about root canal morphology and possible variations, coupled with clinical and radiographic examination in order to increase the ability of clinicians to treat difficult cases. PMID:27471538

  16. 33 CFR 117.438 - Company Canal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Company Canal. 117.438 Section 117.438 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.438 Company Canal. (a) The draw of...

  17. 33 CFR 117.438 - Company Canal.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Company Canal. 117.438 Section 117.438 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.438 Company Canal. (a) The draw of...

  18. 33 CFR 117.438 - Company Canal.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Company Canal. 117.438 Section 117.438 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.438 Company Canal. (a) The draw of...

  19. 33 CFR 117.438 - Company Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Company Canal. 117.438 Section 117.438 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.438 Company Canal. (a) The draw of...

  20. 33 CFR 117.438 - Company Canal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Company Canal. 117.438 Section 117.438 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.438 Company Canal. (a) The draw of...

  1. 33 CFR 117.285 - Grand Canal.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Grand Canal. 117.285 Section 117.285 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.285 Grand Canal. (a) The draw of the Lansing...

  2. 33 CFR 117.285 - Grand Canal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Grand Canal. 117.285 Section 117.285 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.285 Grand Canal. (a) The draw of the Lansing...

  3. 33 CFR 117.285 - Grand Canal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Grand Canal. 117.285 Section 117.285 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.285 Grand Canal. (a) The draw of the Lansing...

  4. 33 CFR 117.444 - Falgout Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Falgout Canal. 117.444 Section 117.444 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.444 Falgout Canal. The draw of the...

  5. [Upper lateral incisor with 2 canals].

    PubMed

    Fabra Campos, H

    1991-01-01

    Clinical case summary of the patient with an upper lateral incisor with two root canals. The suspicion that there might be an anatomic anomaly in the root that includes a complex root canal system was made when an advanced radicular groove was detected in the lingual surface or an excessively enlarged cingulum.

  6. 33 CFR 117.1045 - Hood Canal.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Hood Canal. 117.1045 Section 117.1045 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Washington § 117.1045 Hood Canal. The draw of the Washington...

  7. 33 CFR 117.1045 - Hood Canal.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Hood Canal. 117.1045 Section 117.1045 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Washington § 117.1045 Hood Canal. The draw of the Washington...

  8. Benign lesions of the external auditory canal.

    PubMed

    Tran, L P; Grundfast, K M; Selesnick, S H

    1996-10-01

    Benign mass lesions of the external auditory canal, such as exostoses and osteomas, are common findings on physical examination but most often do not require treatment. The differential diagnosis of lesions in the external auditory canal, however, should not be limited to those benign processes discussed here, but should also include infectious, dermatologic, congenital, and malignant processes.

  9. 33 CFR 117.445 - Franklin Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Franklin Canal. 117.445 Section 117.445 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.445 Franklin Canal. The draw of the Chatsworth Bridge, mile 4.8 at Franklin, shall...

  10. 33 CFR 117.285 - Grand Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Grand Canal. 117.285 Section 117.285 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.285 Grand Canal. (a) The draw of the Lansing Island bridge, mile 0.7, shall open on...

  11. 33 CFR 117.787 - Gowanus Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Gowanus Canal. 117.787 Section 117.787 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New York § 117.787 Gowanus Canal. The draws of the Ninth Street Bridge, mile 1.4, the Third...

  12. 33 CFR 117.453 - Houma Canal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Houma Canal. 117.453 Section 117.453 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.453 Houma Canal. The draw of the S3197 bridge, mile 1.7 at Houma, shall open on signal...

  13. Metoptic canal, duplication of the optic canal and Warwick’s foramen in human orbits.

    PubMed

    Bertelli, Eugenio

    2014-01-01

    The region of the optic strut is sometimes traversed by some minor canals whose incidence and general characteristics have never been studied. As such canals could be the route for vessels that could interfere in the surgery of the orbital apex, we undertook a detailed anatomical study on a vast collection of dry skulls. The examination of 943 dry adult skulls and 360 foetal skulls was carried out to precise the anatomy of canals in the optic strut area, their development and relationships with the optic canal. A canal traversing the optic strut was present in 8.54 % of the orbits. Based on diameter, position within the optic strut, and thickness of the bony plate separating it from the optic canal or from the superior orbital fissure, the canals piercing the optic strut were classified into four types, which include the well-known duplication of the optic canal, different aspects of the metoptic canal and a type of canal that to our knowledge has never been reported. Warwick’s foramen was found in 0.74 % of orbits. The area of the optic strut is the frequent site of canals joining the orbit with the middle cranial fossa. Some of them can host the ophthalmic artery; others could be run by minor vessels which, however, could be the source of annoying bleedings in surgical procedures.

  14. Tissue engineering in endodontics: root canal revascularization.

    PubMed

    Palit Madhu Chanda; Hegde, K Sundeep; Bhat, Sham S; Sargod, Sharan S; Mantha, Somasundar; Chattopadhyay, Sayan

    2014-01-01

    Root canal revascularization attempts to make necrotic tooth alive by the use of certain simple clinical protocols. Earlier apexification was the treatment of choice for treating and preserving immature permanent teeth that have lost pulp vitality. This procedure promoted the formation of apical barrier to seal the root canal of immature teeth and nonvital filling materials contained within root canal space. However with the success of root canal revascularization to regenerate the pulp dentin complex of necrotic immature tooth has made us to rethink if apexification is at the beginning of its end. The objective of this review is to discuss the new concepts of tissue engineering in endodontics and the clinical steps of root canal revascularization.

  15. Horizontal violence among nursing students.

    PubMed

    Longo, Joy

    2007-06-01

    In a research study student nurses in the clinical setting reported experiencing horizontal violence or "nurses eating their young." The types of behaviors most frequently encountered were emotional and verbal attacks. Some students did not report incidences of horizontal violence to their instructors, so it is important that the faculty be cognizant that such behaviors can occur and establish open communication to assist students in dealing with such behaviors.

  16. Total ear canal ablation and lateral bulla osteotomy for treatment of otitis externa and media in a rabbit.

    PubMed

    Chow, Eric P; Bennett, R Avery; Whittington, Julia K

    2011-07-15

    A 7-year-old spayed female Miniature Rex European rabbit (Oryctolagus cuniculus) was evaluated because of scratching at the right ear. Physical examination revealed purulent exudate in the right ear canal. Microbial culture of the exudate yielded Pseudomonas aeruginosa susceptible to marbofloxacin; however, the infection was refractory to appropriate medical treatment. Computed tomography revealed isoattenuating material within the right tympanic bulla and external ear canal with no enhancement following IV administration of contrast medium. The left tympanic bulla appeared normal. A total ear canal ablation and lateral bulla osteotomy were performed on the right ear, and polymethylmethacrylate beads containing either gentamicin or cefazolin were placed within the bulla and surrounding tissues. Two weeks after surgery, the patient appeared comfortable with no signs of scratching at the right ear. Total ear canal ablation and lateral bulla osteotomy can be successfully performed for treatment of chronic otitis externa and media in rabbits. Cartilage plates that compose the external ear canal, a bony acoustic duct, lack of a horizontal ear canal, and thickness of the lateral aspect of the tympanic bulla are features unique to rabbits and have not been described in relation to these surgical procedures in rabbits. Rabbits also produce a caseous exudate, and it is difficult to resolve infections of bone and soft tissues. Placement of antimicrobial-impregnated polymethylmethacrylate beads is recommended to minimize the risk of recurrent infection.

  17. Accuracy of three different electronic apex locators in detecting simulated horizontal and vertical root fractures.

    PubMed

    Ebrahim, Aqeel K; Wadachi, Reiko; Suda, Hideaki

    2006-08-01

    The aim of this in vitro study was to evaluate the accuracy of three electronic apex locators (EALs): Root ZX, Foramatron D10 and Apex NRG, in the detection of fractures in teeth having simulated horizontal and vertical root fractures. A total of 90 extracted intact, straight, single-rooted teeth were divided into six groups of 15 teeth each. In Groups A, B and C, an incomplete horizontal fracture was simulated by preparing a horizontal incision in the coronal, middle or apical portion of the root until the circumferential half of the canal was exposed in the horizontal plane respectively. In Groups D, E and F, an incomplete vertical root fracture was simulated by preparing a vertical straight incision to expose the canal in the coronal, middle or apical portion of the root all the way in the longitudinal plane respectively. The simulated fractures were 0.25 mm in thickness in all groups. The teeth were embedded in 1% agar and the canals were irrigated with saline solution during electronic measurement. Detection of the simulated root fractures was established with a size 10 K-file when the meter value reached 'APEX' on each EAL. In Groups A, B and C, Kruskal-Wallis tests revealed that there were no statistically significant differences between the three EALs. However, statistically significant differences were found among the EALs in Groups D, E and F (P < 0.0001, one-way anova and Tukey's post-hoc test). In conclusion, the three EALs tested were accurate and acceptable clinical tools in the detection of horizontal root fractures. However, the three EALs were unreliable in detecting the position of vertical root fractures.

  18. [Comparative study of root canal morphology of mandibular incisors by cone-beam CT and canal staining and clearing technique].

    PubMed

    Wen, Shan-hui; Lin, Zi-tong; Zhu, Min; Ge, Jiu-yu; Wang, Tie-mei

    2016-02-01

    To compare the root canal morphology of mandibular incisors by using cone-beam CT (CBCT) and canal staining and clearing technique. Sixty-one extracted mandibular incisors with complete dental root and apex which received no endodontic treatment and no post crown restoration were selected. Each tooth was radiographed with CBCT, and the root canal system was stained by canal staining and clearing technique. The consistency of the number of root canal, root canal Vertucci type of mandibular permanent incisors between the two methods were compared, and the differences of the detection rate on root canal branch structure between the two methods were analyzed. The results were statistically analyzed with SPSS 17.0 software package. The Kappa value of single and double root canal types between CBCT and canal staining and clearing technique was 0.847 (P<0.001). The Kappa value of Vertucci root canal types between CBCT and canal staining and clearing technique was 0.861 (P<0.001). The detection rates of root canal branch structure were 8.19% and 22.95%, respectively, with significant difference between the two methods (P=0.025). The canal staining and clearing technique was significantly better than CBCT in detection of root canal branch structure. CBCT can reflect the root canal types nearly perfectly, but inferior to canal staining and clearing technique in detection of root canal branch structure, CBCT is a relatively accurate clinical diagnosis tool of root canal morphology.

  19. Mechanical properties and bond strength of dual-cure resin composites to root canal dentin.

    PubMed

    Aksornmuang, Juthatip; Nakajima, Masatoshi; Foxton, Richard M; Tagami, Junji

    2007-02-01

    To evaluate the regional mechanical properties of dual-cure resin composites and their regional bond strengths to root canal dentin. One of the following dual-cure resin composites was placed in artificial post spaces: Unifil Core (UC), Clearfil DC Core (DC), Build-It FR (BI), Clearfil DC Core-automix (DCA), and photo-cured for 60s. After 24h storage, each specimen was serially sliced to harvest eight hour-glass shaped specimens for measurement of regional ultimate tensile strength (UTS), and the remaining eight semi-circular slabs were polished for the measurement of Knoop Hardness Number (KHN). For the microtensile bond strength (muTBS) test, post cavities were prepared in human premolar roots, and the cavity surfaces treated with Clearfil SE Bond and photo-cured for 10s. The post spaces were then filled with one of the above resin composites and photo-cured for 60s. After 24h storage, each specimen was serially sliced into 8, 0.6x0.6 mm-thick beams for the muTBS test. The data were divided into coronal and apical regions and analyzed using ANOVA and post hoc test (alpha=0.05). UTS and KHN were affected by the type of dual-cure resin composite and region (p<0.0001). There was no relationship between UTS and KHN for each material. The auto-mix type of resin composite possessed superior UTS to that of the hand-mix type. muTBS among the four composite materials were not significantly different at both apical and coronal regions (p>0.05). Regional differences in bond strengths were found for all materials (p<0.05). The UTS and KHN of the dual-cure resin composites varied among each material, however, differences in the mechanical properties of the resin core materials did not affect their adhesion to root canal dentin.

  20. Carpal canal pressure of the distracted wrist.

    PubMed

    Baechler, Martin F; Means, Kenneth R; Parks, Brent G; Nguyen, Augustine; Segalman, Keith A

    2004-09-01

    This study was conducted to study the effect of distraction across the wrist joint on carpal canal pressure. Ten cadaver specimens were mounted vertically in neutral forearm rotation by 2 half pins that transfixed the radius and ulna. The wrist joint was distracted by suspending weights from the middle finger. A balloon-tipped catheter, percutaneously introduced into the carpal canal and connected to a transducer, was used to measure carpal canal pressure. The carpal canal pressure was measured at 0 to 4.54 kg of distraction in 0.45-kg increments and at 6.81 kg and 9.08 kg of distraction. Three wrist positions were tested: neutral, 30 degrees of flexion, and 30 degrees of extension. Highly linear direct relationships between wrist distraction force and carpal canal pressure over baseline were observed in all positions of the wrist. Statistically significant increases in carpal canal pressure over baseline were observed at a wrist distraction force of 2.27 kg or more with the wrist in neutral position, at 1.82 kg or more with the wrist in 30 degrees of extension, and at 4.09 kg or more with the wrist in 30 degrees of flexion. At each level of wrist distraction force of 3.63 kg or less the carpal canal pressure of the extended wrist was significantly higher than that of the wrist in neutral position. At each level of wrist distraction force 4.54 kg or less the carpal canal pressure of the extended wrist was significantly higher than that of the flexed wrist. No statistically significant differences were observed at any level of wrist distraction force between carpal canal pressures in the neutral and flexed positions of the wrist. Distraction across the wrist joint causes a statistically significant highly linear increase in carpal canal pressure. The position of the distracted wrist also has a considerable effect on carpal canal pressure, with the extended position associated with the largest increases in carpal canal pressure and the flexed position with the

  1. Looking back at Love Canal

    SciTech Connect

    Deegan, J. Jr.

    1987-04-01

    The comprehensive environmental study which describes the results of a monitoring program conducted by EPA at Love Canal is evaluated by EPA's former study director. Attention is focused on the episode's history and the agency's study methods. The aim of the program was to constitute a study team, design a monitoring study, reprogram and reallocate the financial resources needed to conduct the study, and identify and employ contractors who would collect and analyze environmental samples. The agency was directed to ensure the quality of the data acquired from various environmental media and analyzed by numerous laboratories; to integrate, interpret, and report the data; and to assess, from an environmental perspective, the habitability of the area.

  2. Micro-computerized tomographic analysis of radicular and canal morphology of premolars with long oval canals.

    PubMed

    Grande, Nicola M; Plotino, Gianluca; Pecci, Raffaella; Bedini, Rossella; Pameijer, Cornelis H; Somma, Francesco

    2008-09-01

    The aims of this in vitro study were to measure root and canal diameters, root and canal diameter ratios, mean taper of the root canal and of each root canal section, and radicular wall thickness at different levels in premolars with long oval root canals. Thirty human premolars, with single long oval canals were selected for this study. The specimens were analyzed with micro-computerized tomography. The cross-sections corresponding to 1, 2, 3, 4, 5, 7, 9, 11, and 13 mm from the radiologic apex were analyzed to measure the mesiodistal (MD) and buccolingual (BL) diameters of the canals and the thickness of the root and the walls. The BL/MD ratios of the canal (DeltaC) and the root (DeltaR) diameters were calculated, as was as the mean taper in both a BL and an MD dimension. Multiple logistic regression analyses were performed with a level of significance of P = .05. At all levels of analysis, the BL diameter was greater than the MD diameter for both the canal and the root. Generally, DeltaC and DeltaR increased coronally. Buccal and lingual wall thicknesses were greater than mesial and distal at all levels. Canal diameters at 1 mm from the apex were >0.30 mm in the shorter-oval diameter and >0.40 mm in the longer-oval diameter. In all root segments the BL taper was greater than the MD taper. An oval canal anatomy was frequently present even in the most apical sections of the root canals. A high correlation was established between the shape of the root canal and the corresponding root.

  3. How to bond to root canal dentin

    NASA Astrophysics Data System (ADS)

    Nica, Luminita; Todea, Carmen; Furtos, Gabriel; Baldea, Bogdan

    2014-01-01

    Bonding to root canal dentin may be difficult due to various factors: the structural characteristic of the root canal dentin, which is different from that of the coronal dentin; the presence of the organic tissue of the dental pulp inside the root canal, which has to be removed during the cleaning-shaping of the root canal system; the smear-layer resulted after mechanical instrumentation, which may interfere with the adhesion of the filling materials; the type of the irrigants used in the cleaning protocol; the type of the sealer and core material used in the obturation of the endodontic space; the type of the materials used for the restoration of the endodontically treated teeth. The influence of the cleaning protocol, of the root canal filling material, of the type of the adhesive system used in the restoration of the treated teeth and of the region of the root canal, on the adhesion of several filling and restorative materials to root canal dentin was evaluated in the push-out bond strength test on 1-mm thick slices of endodontically treated human teeth. The results showed that all these factors have a statistically significant influence on the push-out bond strength. Formation of resin tags between radicular dentin and the investigated materials was observed in some of the samples at SEM analysis.

  4. Treatment of horizontal root fractures using a triple antibiotic paste and mineral trioxide aggregate: a case report.

    PubMed

    Er, Kürşat; Celik, Davut; Taşdemir, Tamer; Yildirim, Tahsin

    2009-07-01

    This case report describes the treatment of a horizontal root fracture in a maxillary central incisor (tooth #8) using a triple antibiotic paste and mineral trioxide aggregate. A nonsurgical endodontic treatment was performed to a coronal root canal fragment of tooth #8. During the treatment procedure, 1% sodium hypochlorite solution was used for irrigation and a triple antibiotic paste was used as an intracanal medicament. The coronal part of the canal was obturated with mineral trioxide aggregate totally. At follow-up examination after 12 months, the tooth was asymptomatic and radiographically showed repair of the fracture region. Healing was achieved without any need for further interventions.

  5. Anterior canal BPPV and apogeotropic posterior canal BPPV: two rare forms of vertical canalolithiasis.

    PubMed

    Califano, L; Salafia, F; Mazzone, S; Melillo, M G; Califano, M

    2014-06-01

    Posterior canal benign paroxysmal positional vertigo (BPPV) is the most frequent form of BPPV. It is characterized by a paroxysmal positioning nystagmus evoked through Dix-Hallpike and Semont positioning tests. Anterior canal BPPV (AC) is more rare than posterior canal BPPV; it presents a prevalent down beating positioning nystagmus, with a torsional component clockwise for the left canal, counterclockwise for the right canal. Due to the possible lack of the torsional component, it is sometimes difficult to identify the affected ear. An apogeotropic variant of posterior BPPV (APC) has recently been described, characterised by a paroxysmal positional nystagmus in the opposite direction to the one evoked in posterior canal BPPV: the linear component is down-beating, the torsional component is clockwise for the right canal, counter-clockwise for the left canal, so that a contra-lateral anterior canal BPPV could be simulated. During a 16 month period, of 934 BPPV patients observed, the authors identified 23 (2.5%) cases of apogeotropic posterior canal BPPV and 11 (1.2%) cases of anterior canal BPPV, diagnosed using the specific oculomotor patterns described in the literature. Anterior canal BPPV was treated with the repositioning manoeuvre proposed by Yacovino, which does not require identification of the affected side, whereas apogeotropic posterior canal BPPV was treated with the Quick Liberatory Rotation manoeuvre for the typical posterior canal BPPV, since in the Dix-Hallpike position otoliths are in the same position if they come either from the ampullary arm or from the non-ampullary arm. The direct resolution of BPPV (one step therapy) was obtained in 12/34 patients, 8/23 patients with APC and 4/11 patients with AC; canalar conversion into typical posterior canal BPPV, later treated through Quick Liberatory Rotation (two-step therapy), was obtained in 19 patients,14/23 with APC and 5/11 with AC. Three patients were lost to follow-up. Considering the effects of

  6. Mandibular Canal Enlargement: Clinical and Radiological Characteristics

    PubMed Central

    Ai, Chong Jun; Jabar, Nazimi Abd; Lan, Tan Huann; Ramli, Roszalina

    2017-01-01

    Enlargement of the mandibular canal is a rare radiological finding. Clinically, it may or may not be associated with sensory deficits. We report four cases of widening of the mandibular canal observed with various methods of imaging with different clinical characteristics. We describe this unique radiological finding and elaborate the importance of quality assessment of the imaging that is vital for accurate diagnosis and treatment planning. Clinicians should be mindful when assessing the imaging whenever the size of the mandibular canal is implicated. The case ranged from a benign tumor to malignancy, radiological errors, and artifacts. A more superior imaging or treatment modality was necessary to ascertain the diagnosis. PMID:28781925

  7. Prosthetic implantation of the human vestibular system

    PubMed Central

    Golub, Justin S.; Ling, Leo; Nie, Kaibao; Nowack, Amy; Shepherd, Sarah J.; Bierer, Steven M.; Jameyson, Elyse; Kaneko, Chris R. S.; Phillips, James O.; Rubinstein, Jay T.

    2015-01-01

    Hypothesis A functional vestibular prosthesis can be implanted in human such that electrical stimulation of each semicircular canal produces canal-specific eye movements while preserving vestibular and auditory function. Background A number of vestibular disorders could be treated with prosthetic stimulation of the vestibular end organs. We have previously demonstrated in rhesus monkeys that a vestibular neurostimulator, based on the Nucleus Freedom cochlear implant, can produce canal-specific electrically evoked eye movements while preserving auditory and vestibular function. An investigational device exemption has been obtained from the FDA to study the feasibility of treating uncontrolled Ménière’s disease with the device. Methods The UW/Nucleus vestibular implant was implanted in the perilymphatic space adjacent to the three semicircular canal ampullae of a human subject with uncontrolled Ménière’s disease. Pre and postoperative vestibular and auditory function were assessed. Electrically evoked eye movements were measured at two time points postoperatively. Results Implantation of all semicircular canals was technically feasible. Horizontal canal and auditory function were largely, but not totally, lost. Electrode stimulation in two of three canals resulted in canal-appropriate eye movements. Over time, stimulation thresholds increased. Conclusions Prosthetic implantation of the semicircular canals in humans is technically feasible. Electrical stimulation resulted in canal-specific eye movements, although thresholds increased over time. Preservation of native auditory and vestibular function, previously observed in animals, was not demonstrated in a single subject with advanced Ménière’s disease. PMID:24317220

  8. Guided implant surgery with modification of the technique involving the raising of a semicircular miniflap: a preliminary study.

    PubMed

    Peñarrocha, María; Viña, José; Maestre, Laura; Peñarrocha, David; Balaguer, José

    2012-09-01

    An evaluation is made of pain, swelling and peri-implant attached mucosal width after implant-based rehabilitation involving guided surgery and a modification of the technique with the raising of a semicircular miniflap, in single and partial replacements. A case-control study was carried out. The study group consisted of 12 patients with the placement of 19 implants using a guided surgery and miniflap technique. The control group consisted of 12 patients with the placement of 22 implants using the conventional technique. Each patient scored postoperative swelling and pain by means of a visual analog scale (VAS). Attached vestibular mucosa width was evaluated 12 weeks after implant placement. Twelve operations were carried out in each group. Immediate aesthetics were established for all implants of the study group. One implant failed in each group. Maximum pain was recorded after 6 hours in both groups (mean VAS score 4 and 4.9 in the study and control group, respectively). Maximum swelling was recorded after 24 hours (mean VAS score 2.5) in the study group and on the second day (mean VAS score 3.4) in the control group. The mean attached vestibular mucosa width was 2.9 mm in the study group and 3.2 mm in the control group. In this preliminary study, guided implant surgery with a semicircular miniflap in single and partial replacements resulted in slightly less postoperative pain and swelling than with the conventional implant technique. The attached vestibular mucosa width was greater in the control group, though the differences were very small.

  9. Guided implant surgery with modification of the technique involving the raising of a semicircular miniflap: A preliminary study

    PubMed Central

    Viña, José; Maestre, Laura; Peñarrocha, David; Balaguer, José

    2012-01-01

    Objective: An evaluation is made of pain, swelling and peri-implant attached mucosal width after implant-based rehabilitation involving guided surgery and a modification of the technique with the raising of a semicircular miniflap, in single and partial replacements. Study design: A case-control study was carried out. The study group consisted of 12 patients with the placement of 19 implants using a guided surgery and miniflap technique. The control group consisted of 12 patients with the placement of 22 implants using the conventional technique. Each patient scored postoperative swelling and pain by means of a visual analog scale (VAS). Attached vestibular mucosa width was evaluated 12 weeks after implant placement. Results: Twelve operations were carried out in each group. Immediate aesthetics were established for all implants of the study group. One implant failed in each group. Maximum pain was recorded after 6 hours in both groups (mean VAS score 4 and 4.9 in the study and control group, respectively). Maximum swelling was recorded after 24 hours (mean VAS score 2.5) in the study group and on the second day (mean VAS score 3.4) in the control group. The mean attached vestibular mucosa width was 2.9 mm in the study group and 3.2 mm in the control group. Conclusion: In this preliminary study, guided implant surgery with a semicircular miniflap in single and partial replacements resulted in slightly less postoperative pain and swelling than with the conventional implant technique. The attached vestibular mucosa width was greater in the control group, though the differences were very small. Key words:Guided surgery, flapless surgery, miniflap, peri-implant mucosa. PMID:22549666

  10. Diagnosis and Treatment of Anterior-Canal Benign Paroxysmal Positional Vertigo: A Systematic Review

    PubMed Central

    Kouzi, Ioanna; Spengos, Konstantinos

    2015-01-01

    Background and Purpose In contrast to the posterior- and horizontal-canal variants, data on the frequency and therapeutic management of anterior-canal benign paroxysmal positional vertigo (AC-BPPV) are sparse. To synthesize the existing body of evidence into a systematic review regarding the incidence and treatment of AC-BPPV. Methods Systematic search of medical databases employing predefined criteria, using the term "anterior canal benign paroxysmal positional vertigo." Results The electronic search retrieved 178 unique citations, 31 of which were considered eligible for further analysis. Analysis of the collected data revealed an estimated occurrence of AC-BPPV among benign paroxysmal positional vertigo patients of 3% (range 1-17.1%). No controlled therapeutic trials could be identified, and so the analysis was focused on uncontrolled case series. Treatment was categorized into three groups: Epley maneuver, Yacovino maneuver, and specific, nonstandard maneuvers described in individual articles. All three categories demonstrated success rates of over 75%, and the overall sample-size-weighted mean was 85.6%. Conclusions The present analysis demonstrated that AC-BPPV comprises about 3% of all BPPV cases. It can be treated safely using the Epley, Yacovino, and other maneuvers with rates of symptom resolution lying in the range of that reported for the other, more frequent canal variants. Multicenter controlled trials are needed in order to develop evidence-based guidelines for the treatment of AC-BPPV. PMID:26022461

  11. Marine Radioactivity Studies in the Suez Canal, Part I: Hydrodynamics and Transit Times

    NASA Astrophysics Data System (ADS)

    Abril, J. M.; Abdel-Aal, M. M.

    2000-04-01

    This paper describes work carried out under the IAEA Project EGY/07/002 to study the dispersion of radioactive material in the Suez Canal. This effort is linked with the increased public concern about radiation safety through this important trade route. To follow the fate of radioactive wastes along this waterway, we had to solve the hydrodynamics of the water, governed mainly by tides, atmospheric forcing and the drift currents produced by horizontal salinity gradients and by differences in mean sea level (MSL) at the two entrances of the Canal. The hydrodynamics has been studied using both 1-D and 2-D modelling approaches, and a reasonable calibration has been possible from the data set prepared with the collaboration of the Suez Canal Authority. Dispersion of conservative pollutants has been preliminarily studied by using a 1-D-Gaussian approach. Thus, we are computing the path of the plumes and the time evolution of concentrations for different scenarios of discharges and under different seasonal conditions. The transit times can vary enormously during the year, ranging from a few days to several months, depending on the differences in MSL at the two entrances of the Canal.

  12. Shope Fibroma in the External Ear Canal of a Domestic Rabbit.

    PubMed

    Cikanek, Shawna J; Carpenter, James W; Lindemann, Dana M; Hallman, R M; Eshar, David; Kim, In Joong; Almes, Kelli M

    2017-02-01

    A 5-y-old, intact, 2.5-kg female domestic rabbit was presented because of blood spatter on the wall of its cage and the toenails of its right hind limb. Physical examination revealed a red, gelatinous mass that spanned the width of the right vertical ear canal. Radiographic images revealed a soft-tissue opacity at the base of the right ear, which was superimposed over the tympanic bulla and extended to the pinna. A CT scan revealed that the soft-tissue mass was within the vertical and horizontal portions of the right external ear canal and extended to the level of the tympanic membrane, with no bony involvement. An incisional biopsy of the mass and subsequent histopathology revealed heterophilic inflammation with bacteria, necrosis, and no evidence of neoplasia. The patient died during anesthesia for removal of the mass at 1 mo after the initial presentation. Necropsy with histopathology of the mass was consistent with Shope fibroma virus in light of the presence of typical intracytoplasmic eosinophilic inclusions. Electron microscopy of paraffin-embedded tissue revealed electron-dense intracytoplasmic structures within neoplastic cells consistent with the diagnosis of Leporipoxvirus. To our knowledge, this report is the first description of Shope fibroma virus invading the external ear canal of a domestic rabbit. Given the results of this case, Shope fibroma should be considered in rabbits presenting with abnormal tissue in the ear canal.

  13. The spatial location of the mandibular canal in Chinese: a CT study.

    PubMed

    Nagadia, R; Tay, A B G; Chan, L L; Chan, E S-Y

    2011-12-01

    The inferior alveolar nerve (IAN) is vulnerable to injury from mandible fractures and surgical procedures so anatomical variations of IAN are important. Postoperative sensory alteration of the lip and chin region is high after mandibular orthognathic surgery. The incidence of IAN paresthesia following sagittal split ramus osteotomy (SSRO) ranges from 54% to 86% at 4-8 days, 41 to 75% at 1 month, 33 to 66% at 3 months, 17 to 58% at 6 months and 15 to 33% at 1 year postoperatively. This study determined the anatomical position of the mandibular canal in relation to cortical bone and molar teeth in Chinese using archived CT records. The mandibular canal was the farthest from the buccal cortex at the second molar region (mean 6.79mm; minimum distance 4.80mm). The anatomical location of the mandibular canal in local Chinese compares with studies on Asian cadavers. The mandible body was thickest in the region of the second molar (11.9mm). The vertical buccal cut for SSRO should be in the region of the mandibular second molar where the bone is thickest and the mandibular canal is furthest from the buccal cortex. The safe depth for the vertical buccal cut is 4.8mm (minimum horizontal distance).

  14. Nurses’ Perceptions of Horizontal Violence

    PubMed Central

    Taylor, Rosemary

    2016-01-01

    In this article, I describe a study exploring horizontal violence and nurses’ perceptions of the phenomenon within the context of two 28-bed inpatient hospital units. The purpose of the study was to develop a clearer understanding of horizontal violence, incorporating observation and inquiry to identify the language nurses use to describe their experiences and factors in the nursing work environment that may perpetuate the phenomenon. Observation, review and analysis of policies, and interviews with staff were completed between June and November 2012. Thematic analysis resulted in five themes: (a) behaviors are minimized and not recognized, (b) fear inhibits all reporting, (c) avoidance and isolation are coping strategies, (d) lack of respect and support, and (e) organizational chaos. The findings suggest future interventions must address a range of factors that perpetuate horizontal violence within the nursing work environment with consideration for the embeddedness and complexity of the phenomenon. PMID:28462334

  15. Nuclear component horizontal seismic restraint

    DOEpatents

    Snyder, Glenn J.

    1988-01-01

    A nuclear component horizontal seismic restraint. Small gaps limit horizontal displacement of components during a seismic occurrence and therefore reduce dynamic loadings on the free lower end. The reactor vessel and reactor guard vessel use thicker section roll-forged rings welded between the vessel straight shell sections and the bottom hemispherical head sections. The inside of the reactor guard vessel ring forging contains local vertical dovetail slots and upper ledge pockets to mount and retain field fitted and installed blocks. As an option, the horizontal displacement of the reactor vessel core support cone can be limited by including shop fitted/installed local blocks in opposing alignment with the reactor vessel forged ring. Beams embedded in the wall of the reactor building protrude into apertures in the thermal insulation shell adjacent the reactor guard vessel ring and have motion limit blocks attached thereto to provide to a predetermined clearance between the blocks and reactor guard vessel ring.

  16. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  17. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  18. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  19. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  20. 21 CFR 872.3810 - Root canal post.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Root canal post. 872.3810 Section 872.3810 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3810 Root canal post. (a) Identification. A root canal... of the platinum group intended to be cemented into the root canal of a tooth to stabilize and...

  1. 6. VIEW SHOWING WOODEN FLUMES ACROSS MARICOPA CANAL. SUCH FLUMES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW SHOWING WOODEN FLUMES ACROSS MARICOPA CANAL. SUCH FLUMES WERE USED TO CARRY WATER FROM ONE CANAL TO ANOTHER, BEFORE THE CANAL COMPANIES WERE BOUGHT BY THE GOVERNMENT, AND THE SYSTEM UNIFIED. Photographer unknown, no date - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  2. Seepage investigations of Noyes Canal, Menard County, Texas

    USGS Publications Warehouse

    Yost, Ivan Dale

    1953-01-01

    At the request of the U.S. Department of Agriculture, Soil Conservation Service, and the Menard Irrigation Company, a seepage investigation was made on Noyes Canal (Menard Irrigation Company Canal) in Menard County, Texas, from the headgates of the canal to where the canal empties back into the San Saba River.

  3. Looking west at lift bridge, canal, and tow path, with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking west at lift bridge, canal, and tow path, with U.S. Rt. 11 bridge in background. Remnant of spur track to R. Paul Smith Power Station is at left, and abandoned Western Maryland Railway right of way parallels canal at right. - Potomac Edison Company, Chesapeake & Ohio Canal Bridge, Spanning C & O Canal South of U.S. 11, Williamsport, Washington County, MD

  4. 149. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    149. TWIN FALLS MAIN CANAL DIVERSION, TWIN FALLS COUNTY, MILNER DAM; CLOSE-UP OF MAIN CANAL GATES, SOUTH VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  5. 97. POINT SPILL, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    97. POINT SPILL, TWIN FALLS MAIN CANAL, TWIN FALLS COUNTY NORTHWEST OF MURTAUGH, IDAHO; OVERALL WEST VIEW FROM CANAL SIDE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  6. 91. CEDAR DRAW SPILL, HIGH LINE CANAL, TWIN FALLS COUNTY, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    91. CEDAR DRAW SPILL, HIGH LINE CANAL, TWIN FALLS COUNTY, SOUTH OF FILER, IDAHO; NORTHEAST VIEW OF CANAL AND GATES. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  7. 28. VIEW FROM IMMEDIATELY DOWNSTREAM OF TWIN FALLS MAIN CANAL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. VIEW FROM IMMEDIATELY DOWNSTREAM OF TWIN FALLS MAIN CANAL HEADWORKS WITH CANAL BRIDGE IN DISTANCE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  8. 150. Photocopy of drawing (taken from Twin Falls Canal Company ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    150. Photocopy of drawing (taken from Twin Falls Canal Company Surveyor's Book #363, Page 42, entitled, 'Diversion Tunnels', located in Twin Falls Canal Company office, Twin Falls, Idaho). PLAN OF DIVERSION TUNNELS, MILNER DAM. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  9. 180. Photocopy of Photograph, Twin Falls Canal Company. E. Pettygro, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    180. Photocopy of Photograph, Twin Falls Canal Company. E. Pettygro, Photographer, date unknown. BLASTING TWIN FALLS CANAL, TWIN FALLS COUNTY; BLASTING COTTONWOOD AREA TO REPLACE FLUME BY RUNNING HIGH LINE THROUGH SOLID ROCK. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  10. 88. CEDAR DRAW SPILL, HIGH LINE CANAL, TWIN FALLS COUNTY, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    88. CEDAR DRAW SPILL, HIGH LINE CANAL, TWIN FALLS COUNTY, SOUTH OF FILER, IDAHO; WEST VIEW OF CANAL AND GATES. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  11. 94. CEDAR DRAW SPILL, LOW LINE CANAL, TWIN FALLS COUNTY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    94. CEDAR DRAW SPILL, LOW LINE CANAL, TWIN FALLS COUNTY SOUTH OF FILER, IDAHO; CLOSE-UP OF GATES FROM THE CANAL SIDE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  12. 123. MCMULLEN CREEK, HIGH LINE CANAL, TWIN FALLS COUNTY, SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    123. MCMULLEN CREEK, HIGH LINE CANAL, TWIN FALLS COUNTY, SOUTH OF KIMBERLY, IDAHO; SOUTH VIEW OF THE CREEK EMPTYING INTO THE HIGH LINE CANAL. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  13. 131. FORKS DIVERSION, HIGH LINE AND LOW LINE CANALS, TWIN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    131. FORKS DIVERSION, HIGH LINE AND LOW LINE CANALS, TWIN FALLS COUNTY, SOUTH OF HANSEN, IDAHO; INLET SIDE OF LOW LINE CANAL, WEST VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  14. 177. Photocopy of Photograph, Twin Falls Canal Company, Bisbee Photo, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    177. Photocopy of Photograph, Twin Falls Canal Company, Bisbee Photo, September, 1912. Photographer unknown. COTTONWOOD FLUME, HIGH LINE CANAL, TWIN FALLS COUNTY, SOUTH OF KIMBERLY, IDAHO; SOUTH VIEW FROM UPPER SIDE. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  15. 189. Photocopy of drawing, Twin Falls Canal Company, date unknown. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    189. Photocopy of drawing, Twin Falls Canal Company, date unknown. ROCK CREEK CROSSING, LOW LINE CANAL, TWIN FALLS COUNTY, SOUTH OF KIMBERLY, IDAHO; BLUEPRINT. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  16. 89. CEDAR DRAW SPILL, HIGH LINE CANAL, TWIN FALLS COUNTY, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    89. CEDAR DRAW SPILL, HIGH LINE CANAL, TWIN FALLS COUNTY, SOUTH OF FILER, IDAHO; OUTLET SIDE OF CANAL, SOUTHWEST VIEW. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  17. 158. Photocopy of transit book (taken from Twin Falls Canal ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    158. Photocopy of transit book (taken from Twin Falls Canal Company Transit Book #404T, Page 3, #46, Division One). START OF MAIN CANAL SURVEY, TWIN FALLS COUNTY, MILNER, IDAHO. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  18. 154. Photocopy of transit book (taken from Twin Falls Canal ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    154. Photocopy of transit book (taken from Twin Falls Canal Company Surveyor's Transit Book #405T, Page 2, #46 Division One). STATEMENT OF SIGHT-SETTING FOR 1903 SURVEY TO ALIGN SOUTH SIDE CANAL, TWIN FALLS COUNTY, MILNER, IDAHO. - Milner Dam & Main Canal: Twin Falls Canal Company, On Snake River, 11 miles West of city of Burley, Idaho, Twin Falls, Twin Falls County, ID

  19. 3. Dundee Canal looking northwest from north of Dundee Textile ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Dundee Canal looking northwest from north of Dundee Textile Company Mill - Dundee Canal Industrial Historic District, Beginning at George Street in Passaic & extending north along Dundee Canal approximately 1.2 miles to Canal headgates opposite East Clifton Avenue in Clifton, Passaic, Passaic County, NJ

  20. [Scanning electron microscopy investigation of canal cleaning after canal preparation with nickel titanium files].

    PubMed

    Brkanić, Tatjana; Ivana, Stojsin; Vukoje, Karolina; Zivković, Slavoljub

    2010-01-01

    Root canal preparation is the most important phase of endodontic procedure and it consists of adequate canal space cleaning and shaping. In recent years, rotary instruments and techniques have gained importance because of the great efficacy, speed and safety of the preparation procedure. The aim of this research was to investigate the influence of different NiTi files on the canal wall cleaning quality, residual dentine debris and smear layer. The research was conducted on extracted human teeth in vitro conditions. Teeth were divided in 7 main groups depending on the kind of instruments used for root canal preparation: ProTaper, GT, ProFile, K-3, FlexMaster, hand ProTaper and hand GT. Root canal preparation was accomplished by crown-down technique. Prepared samples were assessed on scanning electron microscopy JEOL, JSM-6460 LV. The evaluation of dentine debris was done with 500x magnification, and the evaluation of smear layer with 1,000 times magnification. Quantitive assessment of dentine debris and smear layer was done according to the criteria of Hulsmann. The least amount of debris and smear layer has been found in canals shaped with ProFile instruments, and the largest amount in canals shaped with FlexMaster instruments. Canal cleaning efficacy of hand GTand ProTaperfiles has been similar to cleaning efficacy of rotary NiTi files. Statistic analysis has shown a significant difference in amount of dentine debris and smear layer on the canal walls between sample groups. shaped with different instruments. Completely clean canals have not been found in any tested group of instruments. The largest amount of debris and smear layer has been found in the apical third of all canals. The design and the type of endodontic instruments influence the efficacy of the canal cleaning.

  1. Success in horizontal barrier developments

    SciTech Connect

    Pettit, P.J.; Ridenour, D.E.; Jalovec, J.

    1996-06-01

    A successful proof of concept demonstration has been conducted of operational methods and tooling for the in situ construction of underground horizontal barriers for the control and containment of groundwater and contamination. The method involves jet grouting with specially adapted tools guided between twin, parallel wells for the placement of a grout beneath a waste site. The objective of the work is to develop reliable methods of constructing extensive, competent horizontal barriers underneath waste sites without excavating or penetrating the waste during the process.

  2. Speckle Imaging Over Horizontal Paths

    SciTech Connect

    Carrano, C J

    2002-05-21

    Atmospheric aberrations reduce the resolution and contrast in surveillance images recorded over horizontal or slant paths. This paper describes our recent horizontal and slant path imaging experiments of extended scenes as well as the results obtained using speckle imaging. The experiments were performed with an 8-inch diameter telescope placed on either a rooftop or hillside and cover ranges of interest from 0.5 km up to 10 km. The scenery includes resolution targets, people, vehicles, and other structures. The improvement in image quality using speckle imaging is dramatic in many cases, and depends significantly upon the atmospheric conditions. We quantify resolution improvement through modulation transfer function measurement comparisons.

  3. 7. View north at back (canal side) of culvert inlet, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. View north at back (canal side) of culvert inlet, with canal bank completely removed. Background to foreground: back of inlet headwall with tops of high inlet barrels exposed; vertical transition wall between high inlet barrels and low, interior, inlet barrels; tops of low interior barrels; vertical heartening planks and low cutoff wall at site of former canal edge of canal bank; dewatered canal bed and plank sheathing on top of culvert barrels beneath canal bed. - Delaware & Raritan Canal, Ten Mile Run Culvert, 1.5 miles South of Blackwells Road, East Millstone, Somerset County, NJ

  4. Adapting fiber-reinforced composite root canal posts for use in noncircular-shaped canals.

    PubMed

    Grande, Nicola Maria; Butti, Andrea; Plotino, Gianluca; Somma, Francesco

    2006-10-01

    Post placement in oval-shaped root canals implies the sacrifice of sound dental tissue to adapt the canal shape to fit the post, which can result in one of several significant complications. A semidirect, single-visit, chairside procedure is proposed, which permits the use of an almost anatomically shaped post, starting from a preformed fiber-reinforced composite root canal post of the largest size commercially available. The utilization of this post capitalizes on the advantages of both the fiber post and the anatomical post in oval- and ribbon-shaped canals to provide restoration of endodontically treated teeth.

  5. 8. VIEW SHOWING THE DEMOSSING OF GRAND CANAL LOCATION UNKNOWN. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. VIEW SHOWING THE DEMOSSING OF GRAND CANAL LOCATION UNKNOWN. AT TEAM OF HORSES ON OPPOSITE BANKS OF THE CANAL DRAG A CHAIN BETWEEN THEM ALONG THE BOTTOM OF THE CANAL, WHICH PULLS THE MOSS AND WEEDS LOOSE. THE PLANS THEN FLOAT DOWN THE CANAL AND ARE CAUGHT IN A SCREEN AND REMOVED. Photographer unknown, 1923 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  6. CT appearances of external ear canal cholesteatoma.

    PubMed

    Malcolm, P N; Francis, I S; Wareing, M J; Cox, T C

    1997-09-01

    External ear canal cholesteatoma (EECC) is rare in ear, nose and throat (ENT) practice. Two cases, one bilateral, are described. Computed tomography demonstrates the extent of bony involvement. Erosion of the external canal should not be overlooked when reviewing CT of the petrous bone in cases of discharge from the ear. EECC may necessitate surgery and delay in the diagnosis of EECC can result in progressive bony destruction.

  7. Mechanics of the Panama Canal slides

    USGS Publications Warehouse

    Becker, George F.

    1917-01-01

    Dr. Becker visited the Canal Zone in 1913 as a geologist of the United States Geological Survey and since that time has given the problem the benefit of his study. His appointment as a member of the committee of the National Academy of Sciences has made it appropriate for his conclusions, based upon his personal observations and already reported in part to the Canal Commission, to be stated for the benefit of his associates and other American scientists and engineers.

  8. Formation of actin filament bundles in the ring canals of developing Drosophila follicles

    PubMed Central

    1996-01-01

    Growing the intracellular bridges that connect nurse cells with each o ther and to the developing oocyte is vital for egg development. These ring canals increase from 0.5 microns in diameter at stage 2 to 10 microns in diameter at stage 11. Thin sections cut horizontally as you would cut a bagel, show that there is a layer of circumferentially oriented actin filaments attached to the plasma membrane at the periphery of each canal. By decoration with subfragment 1 of myosin we find actin filaments of mixed polarities in the ring such as found in the "contractile ring" formed during cytokinesis. In vertical sections through the canal the actin filaments appear as dense dots. At stage 2 there are 82 actin filaments in the ring, by stage 6 there are 717 and by stage 10 there are 726. Taking into account the diameter, this indicates that there is 170 microns of actin filaments/canal at stage 2 (pi x 0.5 microns x 82), 14,000 microns at stage 9 and approximately 23,000 microns at stage 11 or one inch of actin filament! The density of actin filaments remains unchanged throughout development. What is particularly striking is that by stages 4-5, the ring of actin filaments has achieved its maximum thickness, even though the diameter has not yet increased significantly. Thereafter, the diameter increases. Throughout development, stages 2-11, the canal length also increases. Although the density (number of actin filaments/micron2) through a canal remains constant from stage 5 on, the actin filaments appear as a net of interconnected bundles. Further information on this net of bundles comes from studying mutant animals that lack kelch, a protein located in the ring canal that has homology to the actin binding protein, scruin. In this mutant, the actin filaments form normally but individual bundles that comprise the fibers of the net are not bound tightly together. Some bundles enter into the ring canal lumen but do not completely occlude the lumen. all these observations lay

  9. Regenerative Endodontic Procedures for Traumatized Teeth after Horizontal Root Fracture, Avulsion, and Perforating Root Resorption.

    PubMed

    Saoud, Tarek Mohamed A; Mistry, Sonali; Kahler, Bill; Sigurdsson, Asgeir; Lin, Louis M

    2016-10-01

    Traumatic injury to the teeth can cause horizontal root fractures and inflammatory root resorptions (external and internal). Traditionally, traumatized teeth with horizontal root fractures resulting in pulp necrosis and inflammatory root resorptions are treated with conventional root canal therapy. A 15-year-old boy had a history of traumatic injury to mature tooth #8 resulting in horizontal root fracture and pulp necrosis of the coronal fragment. A 7-year-old girl suffered an avulsion injury to immature tooth #9, which developed inflammatory replacement resorption and subsequently root fractured 15 months later. Another 16-year-old boy also suffered a history of traumatic injury to mature tooth #8, resulting in perforating root resorption. All teeth were treated with regenerative endodontic procedures using chemomechanical debridement, calcium hydroxide/triple antibiotic paste dressing, EDTA rinse, induction of periapical bleeding into the canal space, and a coronal mineral trioxide aggregate plug. In the tooth presenting with horizontal root fracture, only the coronal fragment was treated to preserve pulp vitality in the apical fragment for possible pulp tissue regeneration. After regenerative endodontic procedures, clinical signs/symptoms subsided, and inflammatory osteolytic lesions resolved in all traumatized teeth. Two teeth were followed for 19 months and 1 tooth for 5 years. At the last review of the teeth with horizontal root fractures, the first case showed healing by calcified tissue and the second case showed healing by fibrous connective and hard tissue. Tooth with perforating root resorption demonstrated a decrease in size of the resorptive defect. Based on these case reports, regenerative endodontic procedures have the potential to be used to treat traumatized teeth with horizontal root fracture and inflammatory root resorption. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  10. Horizontal electric fields from lightning return strokes

    NASA Technical Reports Server (NTRS)

    Thomson, E. M.; Medelius, P. J.; Rubinstein, M.; Uman, M. A.; Johnson, J.

    1988-01-01

    An experiment to measure simultaneously the wideband horizontal and vertical electric fields from lightning return strokes is described. Typical wave shapes of the measured horizontal and vertical fields are presented, and the horizontal fields are characterized. The measured horizontal fields are compared with calculated horizontal fields obtained by applying the wavetilt formula to the vertical fields. The limitations and sources of error in the measurement technique are discussed.

  11. Horizontal drilling installs dutch waterline

    SciTech Connect

    Not Available

    1986-08-01

    A 32-in. potable water line system, installed by Van Eijk Leidingen B.V. in Holland, was laid through an intensively cultivated vegetable gardening area, and designed to furnish additional irrigation water. Using a horizontally drilled 42-in. hole under the Maasdijk, though a difficult job, reduced the length by more than 3 miles.

  12. Disinfection of Contaminated Canals by Different Laser Wavelengths, while Performing Root Canal Therapy

    PubMed Central

    Asnaashari, Mohammad; Safavi, Nassimeh

    2013-01-01

    Removal of smear layer and disinfection of canals are important objectives of teeth root canal cleaning. In order to achieve this purpose, rinsing substances, intra canal drugs as well as ultrasound are used. Today, use of laser to remove smear layer and to disinfect root canals has increasingly attracted the attentions. Till now different lasers such as CO2, Nd:YAG, Er:YAG, Er,Cr:YSGG have been used for debris and smear removal from the canals. Numerous studies have shown that Er:YAG is the most appropriate laser for intra canal debris and smear removal. In addition different laser wavelengths have been used directly or as an adjunctive to disinfect canals. Laser light can penetrate areas of canals where irrigating and disinfecting solutions cannot reach, like secondary canals and deep dentinal tubules and also can eliminate microorganisms. Different studies have confirmed the penetration of Nd:YAG laser in deep dentin and reduction of microorganisms penetration. But studies on comparison of antibacterial effects of Nd:YAG laser with sodium hypochlorite showed effectiveness of both, with a better effect for sodium hypochlorite. Studies performed in relation with anti-microbial effects of Diode laser with various parameters show that this laser can be effective in reducing intra canal bacterial count and penetration in the depth of 500 microns in dentin. In studies performed on Diode laser in combination with canal irrigating solutions such as sodium hypochlorite and oxygenated water better results were obtained. Although studies on disinfection by the Erbium laser family show that use of this laser alone can be effective in disinfecting canals, studies evaluating the disinfecting effects of this laser and different concentrations of sodium hypochlorite show that the latter alone is more effective in disinfecting canals. And better results were obtained when Erbium laser was used in combination with sodium hypochlorite irrigating solution in canals. Results of the

  13. Disinfection of Contaminated Canals by Different Laser Wavelengths, while Performing Root Canal Therapy.

    PubMed

    Asnaashari, Mohammad; Safavi, Nassimeh

    2013-01-01

    Removal of smear layer and disinfection of canals are important objectives of teeth root canal cleaning. In order to achieve this purpose, rinsing substances, intra canal drugs as well as ultrasound are used. Today, use of laser to remove smear layer and to disinfect root canals has increasingly attracted the attentions. Till now different lasers such as CO2, Nd:YAG, Er:YAG, Er,Cr:YSGG have been used for debris and smear removal from the canals. Numerous studies have shown that Er:YAG is the most appropriate laser for intra canal debris and smear removal. In addition different laser wavelengths have been used directly or as an adjunctive to disinfect canals. Laser light can penetrate areas of canals where irrigating and disinfecting solutions cannot reach, like secondary canals and deep dentinal tubules and also can eliminate microorganisms. Different studies have confirmed the penetration of Nd:YAG laser in deep dentin and reduction of microorganisms penetration. But studies on comparison of antibacterial effects of Nd:YAG laser with sodium hypochlorite showed effectiveness of both, with a better effect for sodium hypochlorite. Studies performed in relation with anti-microbial effects of Diode laser with various parameters show that this laser can be effective in reducing intra canal bacterial count and penetration in the depth of 500 microns in dentin. In studies performed on Diode laser in combination with canal irrigating solutions such as sodium hypochlorite and oxygenated water better results were obtained. Although studies on disinfection by the Erbium laser family show that use of this laser alone can be effective in disinfecting canals, studies evaluating the disinfecting effects of this laser and different concentrations of sodium hypochlorite show that the latter alone is more effective in disinfecting canals. And better results were obtained when Erbium laser was used in combination with sodium hypochlorite irrigating solution in canals. Results of the

  14. The fluid mechanics of root canal irrigation.

    PubMed

    Gulabivala, K; Ng, Y-L; Gilbertson, M; Eames, I

    2010-12-01

    Root canal treatment is a common dental operation aimed at removing the contents of the geometrically complex canal chambers within teeth; its purpose is to remove diseased or infected tissue. The complex chamber is first enlarged and shaped by instruments to a size sufficient to deliver antibacterial fluids. These irrigants help to dissolve dying tissue, disinfect the canal walls and space and flush out debris. The effectiveness of the procedure is limited by access to the canal terminus. Endodontic research is focused on finding the instruments and clinical procedures that might improve success rates by more effectively reaching the apical anatomy. The individual factors affecting treatment outcome have not been unequivocally deciphered, partly because of the difficulty in isolating them and in making the link between simplified, general experimental models and the complex biological objects that are teeth. Explicitly considering the physical processes within the root canal can contribute to the resolution of these problems. The central problem is one of fluid motion in a confined geometry, which makes the dispersion and mixing of irrigant more difficult because of the absence of turbulence over much of the canal volume. The effects of treatments can be understood through the use of scale models, mathematical modelling and numerical computations. A particular concern in treatment is that caustic irrigant may penetrate beyond the root canal, causing chemical damage to the jawbone. In fact, a stagnation plane exists beyond the needle tip, which the irrigant cannot penetrate. The goal is therefore to shift the stagnation plane apically to be coincident with the canal terminus without extending beyond it. Needle design may solve some of the problems but the best design for irrigant penetration conflicts with that for optimal removal of the bacterial biofilm from the canal wall. Both irrigant penetration and biofilm removal may be improved through canal fluid

  15. Application of software for automated canal management (SacMan) to the WM lateral canal

    USDA-ARS?s Scientific Manuscript database

    Simulation studies have demonstrated that automatic control of canals is more effective when feedforward scheduling, or routing of know demand changes, is combined with centralized, automatic, distant, downstream-water-level control. In practice, few canals use this approach. To help further develop...

  16. Plasticity of the human otolith-ocular reflex

    NASA Technical Reports Server (NTRS)

    Wall, C. 3rd; Smith, T. R.; Furman, J. M.

    1992-01-01

    The eye movement response to earth vertical axis rotation in the dark, a semicircular canal stimulus, can be altered by prior exposure to combined visual-vestibular stimuli. Such plasticity of the vestibulo-ocular reflex has not been described for earth horizontal axis rotation, a dynamic otolith stimulus. Twenty normal human subjects underwent one of two types of adaptation paradigms designed either to attenuate or enhance the gain of the semicircular canal-ocular reflex prior to undergoing otolith-ocular reflex testing with horizontal axis rotation. The adaptation paradigm paired a 0.2 Hz sinusoidal rotation about a vertical axis with a 0.2 Hz optokinetic stripe pattern that was deliberately mismatched in peak velocity. Pre- and post-adaptation horizontal axis rotations were at 60 degrees/s in the dark and produced a modulation in the slow component velocity of nystagmus having a frequency of 0.17 Hz due to putative stimulation of the otolith organs. Results showed that the magnitude of this modulation component response was altered in a manner similar to the alteration in semicircular canal-ocular responses. These results suggest that physiologic alteration of the vestibulo-ocular reflex using deliberately mismatched visual and semicircular canal stimuli induces changes in both canal-ocular and otolith-ocular responses. We postulate, therefore, that central nervous system pathways responsible for controlling the gains of canal-ocular and otolith-ocular reflexes are shared.

  17. Plasticity of the human otolith-ocular reflex

    NASA Technical Reports Server (NTRS)

    Wall, C. 3rd; Smith, T. R.; Furman, J. M.

    1992-01-01

    The eye movement response to earth vertical axis rotation in the dark, a semicircular canal stimulus, can be altered by prior exposure to combined visual-vestibular stimuli. Such plasticity of the vestibulo-ocular reflex has not been described for earth horizontal axis rotation, a dynamic otolith stimulus. Twenty normal human subjects underwent one of two types of adaptation paradigms designed either to attenuate or enhance the gain of the semicircular canal-ocular reflex prior to undergoing otolith-ocular reflex testing with horizontal axis rotation. The adaptation paradigm paired a 0.2 Hz sinusoidal rotation about a vertical axis with a 0.2 Hz optokinetic stripe pattern that was deliberately mismatched in peak velocity. Pre- and post-adaptation horizontal axis rotations were at 60 degrees/s in the dark and produced a modulation in the slow component velocity of nystagmus having a frequency of 0.17 Hz due to putative stimulation of the otolith organs. Results showed that the magnitude of this modulation component response was altered in a manner similar to the alteration in semicircular canal-ocular responses. These results suggest that physiologic alteration of the vestibulo-ocular reflex using deliberately mismatched visual and semicircular canal stimuli induces changes in both canal-ocular and otolith-ocular responses. We postulate, therefore, that central nervous system pathways responsible for controlling the gains of canal-ocular and otolith-ocular reflexes are shared.

  18. Horizontal-branch stellar evolution

    NASA Technical Reports Server (NTRS)

    Sweigart, Allen V.

    1990-01-01

    The results of canonical theory for the evolution of horizontal-branch (HB) stars are examined. Particular attention is given to how an HB star maintains the appropriate composition distribution within the semiconvective zone and how this composition is affected by the finite time-dependence with which convective boundaries actually move. Newly developed models based on time-dependent overshooting are presented for both the core-helium-exhaustion and main HB phases.

  19. Airplanes in Horizontal Curvilinear Flight

    NASA Technical Reports Server (NTRS)

    Kann, Heinrich

    1924-01-01

    War airplanes require not only high speed and the ability to climb rapidly, but also the ability to transverse sharp curves quickly. Here, an attempt is made to give a simple method of calculating horizontal curvilinear flight. A method for determining the area of the aileron and rubber surfaces are also indicated. The discussion given here applies primarily to single and two-seater airplanes, although it can be extended to larger airplanes.

  20. Evaluation of Distolingual Canal/Roots in Mandibular Molars and Mesiobuccal Canals in Maxillary Molars by CBCT.

    PubMed

    Pekiner, Filiz Namdar; Borahan, M Oğuz; Dumlu, Asım

    2017-01-01

    The objectives of this study were to identify the bilateral distolingual (DL) canals / roots of the mandibular first molars and second mesiobuccal (MB2) canals of the maxillary first molars in the same Turkish individuals using cone-beam computed tomography (CBCT). A total of 150 CBCT images including all mandibular and maxillary first molars were retrospectively investigated in a Turkish subpopulation. The patient age, sex and presence of roots and root canals were assessed. The frequency, of bilateral DL canals, DL roots, and MB2 canals were reviewed. Data were analyzed using Fisher'sexact test and Chi-square test. The prevalences of right DL canals, DL roots and MB2 canals were 31.3, 14.0 and 34.7%, respectively. The prevalences of left DL canals, DL roots and MB2 canals were 31.3, 4 and 27.3%, respectively. There was no statistically difference in the frequency of right and left DL canals, DL roots of mandibular first molars and MB2 canals of maxillary first molars according to gender. CBCT is a competent tool for the detection of additional distolingual canals/roots and second mesio buccal canals, and it is a valuable aid for dentists providing root canal treatment.

  1. Function of lateral line canal morphology.

    PubMed

    Klein, Adrian; Bleckmann, Horst

    2015-01-01

    Fish perceive water motions and pressure gradients with their lateral line. Lateral line information is used for prey detection, spatial orientation, predator avoidance, schooling behavior, intraspecific communication and station holding. The lateral line of most fishes consists of superficial neuromasts (SNs) and canal neuromasts (CNs). The distribution of SNs and CNs shows a high degree of variation among fishes. Researchers have speculated for decades about the functional significance of this diversity, often without any conclusive answers. Klein et al. (2013) examined how tubules, pore number and pore patterns affect the filter properties of lateral line canals in a marine teleost, the black prickleback (Xiphister atropurpureus). A preliminary mathematical model was formulated and biomimetic sensors were built. For the present study the mathematical model was extended to understand the major underlying principle of how canal dimensions influence the filter properties of the lateral line. Both the extended mathematical model and the sensor experiments show that the number and distribution of pores determine the spatial filter properties of the lateral line. In an environment with little hydrodynamic noise, simple and complex lateral line canals have comparable response properties. However, if exposed to highly turbulent conditions, canals with numerous widely spaced pores increase the signal to noise ratio significantly. © 2014 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

  2. Preceramic irrigation canals in the Peruvian Andes

    PubMed Central

    Dillehay, Tom D.; Eling, Herbert H.; Rossen, Jack

    2005-01-01

    One of the most important developments in the existence of human society was the successful shift from a subsistence economy based on foraging to one primarily based on food production derived from cultivated plants and domesticated animals. The shift to plant food production occurred in only a few independent centers around the world and involved a commitment to increased sedentism and social interaction and to permanent agricultural fields and canals. One center was Peru, where early civilization and food production were beginning to develop by at least 4,500 years ago. New archeological evidence points to 5,400- and possible 6,700-year-old small-scale gravity canals in a circumscribed valley of the western Andean foothills in northern Peru that are associated with farming on low terrace benches at the foot of alluvial fans in areas where the canals are drawn from hydraulically manageable small lateral streams. This evidence reveals early environmental manipulation and incipient food production in an artificially created wet agroecosystem rather than simply the intensive harvesting or gardening of plants in moist natural areas. This finding is different from previously conceived notions, which expected early canals in lower-elevated, broad coastal valleys. The evidence also points to communal organization of labor to construct and maintain the canals and to the scheduling of daily activities beyond individual households. The development of early organized irrigation farming was combined with a hunting and gathering economy to support an increase in the local population size. PMID:16284247

  3. Malignant Melanoma of the External Auditory Canal

    PubMed Central

    Kumar, Prasanna; Ravikumar, A; Joseph, Leena Dennis; Rajendiran, Swaminathan

    2014-01-01

    Primary malignant melanoma of the external auditory canal is rarely reported. Malignant melanoma of the ear is estimated to occur in 1-4% of all skin melanomas and about 7-20% of melanomas of the head and neck region. The pathophysiology of these tumours is different from other skin lesions because of their anatomical and functional characteristics. The case presented is of a 11 year old female child with malignant melanoma of the external auditory canal confined to the right side, who initially presented with right ear pain, bleeding, post auricular swelling and also a mass in the external auditory canal which was thought to be an aural polyp in the right ear. Excision of the tumour was accomplished by a radical mastoidectomy. It was confirmed to be malignant melanoma after histopathological examination and Immunohistochemistry. Despite all efforts, the patient succumbed to the disease after receiving three cycles of chemotherapy. Even though this malignancy is rarely found in the external auditory canal, it should be expanded into the differential diagnosis of an aural polyp and a post aural abscess. The incidence, symptoms, investigations, treatment and prognosis of malignant melanoma of the external auditory canal is discussed in this article. PMID:25302202

  4. Preceramic irrigation canals in the Peruvian Andes.

    PubMed

    Dillehay, Tom D; Eling, Herbert H; Rossen, Jack

    2005-11-22

    One of the most important developments in the existence of human society was the successful shift from a subsistence economy based on foraging to one primarily based on food production derived from cultivated plants and domesticated animals. The shift to plant food production occurred in only a few independent centers around the world and involved a commitment to increased sedentism and social interaction and to permanent agricultural fields and canals. One center was Peru, where early civilization and food production were beginning to develop by at least 4,500 years ago. New archeological evidence points to 5,400- and possible 6,700-year-old small-scale gravity canals in a circumscribed valley of the western Andean foothills in northern Peru that are associated with farming on low terrace benches at the foot of alluvial fans in areas where the canals are drawn from hydraulically manageable small lateral streams. This evidence reveals early environmental manipulation and incipient food production in an artificially created wet agroecosystem rather than simply the intensive harvesting or gardening of plants in moist natural areas. This finding is different from previously conceived notions, which expected early canals in lower-elevated, broad coastal valleys. The evidence also points to communal organization of labor to construct and maintain the canals and to the scheduling of daily activities beyond individual households. The development of early organized irrigation farming was combined with a hunting and gathering economy to support an increase in the local population size.

  5. Estimation of the lifetime of a trapped vortex in a circular cavern on a semicircular airfoil streamlined at a zero angle of attack after switching off slot suction

    NASA Astrophysics Data System (ADS)

    Isaev, S. A.; Baranov, P. A.; Sudakov, A. G.; Popov, I. A.; Usachov, A. E.

    2017-04-01

    The restructuring of the periodic structure of a turbulent streamline for a semicircular airfoil at a zero angle of attack with a system of slot suction from the circular cavern switched off is calculated. Multiblock numerical methods are applied for solution of Reynolds-averaged nonstationary Navier-Stokes equations closed using the modified shear-stress transfer model taking into account flow line curvature. The lifetime of a trapped vortex in a circular cavern is estimated.

  6. Comparison of air-driven vs electric torque control motors on canal centering ability by ProTaper NiTi rotary instruments.

    PubMed

    Zarei, Mina; Javidi, Maryam; Erfanian, Mahdi; Lomee, Mahdi; Afkhami, Farzaneh

    2013-01-01

    Cleaning and shaping is one of the most important phases in root canal therapy. Various rotary NiTi systems minimize accidents and facilitate the shaping process. Todays NiTi files are used with air-driven and electric handpieces. This study compared the canal centering after instrumentation using the ProTaper system using Endo IT, electric torque-control motor, and NSK air-driven handpiece. This ex vivo randomized controlled trial study involved 26 mesial mandibular root canals with 10 to 35° curvature. The roots were randomly divided into 2 groups of 13 canals each. The roots were mounted in an endodontic cube with acrylic resin, sectioned horizontally at 2, 6 and 10 mm from the apex and then reassembled. The canals were instrumented according to the manufacturer's instructions using ProTaper rotary files and electric torque-control motors (group 1) or air-driven handpieces (group 2). Photographs of the cross-sections included shots before and after instrumentation, and image analysis was performed using Photoshop software. The centering ability and canal transportation was also evaluated. Repeated measurement and independent t-test provided statistical analysis of canal transportation. The comparison of the rate of transportation toward internal or external walls between the two groups was not statistically significant (p = 0.62). Comparison of the rate of transportation of sections within one group was not significant (p = 0.28). Use of rotary NiTi file with either electric torquecontrol motor or air-driven handpiece had no effect on canal centering. NiTi rotary instruments can be used with air-driven motors without any considerable changes in root canal anatomy, however it needs the clinician to be expert.

  7. Root Canal Surface Strain and Canal Center Transportation Induced by 3 Different Nickel-Titanium Rotary Instrument Systems.

    PubMed

    Liu, Wenzhe; Wu, Buling

    2016-02-01

    Root canal anatomy and canal preparation instruments affect the outcome of endodontic treatment. The purpose of this study was to determine the root surface strain (SS) generated and the extent of canal center transportation during canal shaping using 3 different nickel-titanium instruments. Simulated root canals in resin blocks (n = 10 per group) were prepared using adaptive rotary motion with twisted files (Twisted File Adaptive [TFA]; SybronEndo, Orange, CA), reciprocating rotary motion with WaveOne (WO; Dentsply Maillefer, Ballaigues, Switzerland) files, and continuous rotary motion with ProTaper Next files (PTN, Dentsply Maillefer). Electrical strain gauges at 3 sites recorded SS real time during canal shaping, and the blocks were scanned by micro-computed tomographic imaging to assess the canal center deviation at 3 sections after root canal instrumentation. The mean maximum SS and the canal center transportation for all groups and sites were derived and analyzed for a possible correlation between them. An overall increase in root SS was observed after root canal instrumentation. A significant difference in the induced mean maximum SS between TFA, WO, and PTN at specific sites of curved root canals was observed. A statistically significant difference in the mean distance of canal center transportation was observed among the 3 shaping techniques at the apical section. Finally, the mean maximum SS values induced during canal shaping strongly correlated with canal center transportation in the apical section and the coronal section. The curved canals prepared using TFA exhibited lower SS and less canal center transportation at the apical section than the WO and PTN systems. SS generated during canal shaping correlated with canal center transportation in a site-specific manner. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  8. Industry survey for horizontal wells. Final report

    SciTech Connect

    Wilson, D.D.; Kaback, D.S.; Denhan, M.E.; Watkins, D.

    1993-07-01

    An international survey of horizontal environmental wells was performed during May and June of 1993. The purpose of the survey was to provide the environmental industry with an inventory of horizontal environmental wells and information pertaining to the extent of the use of horizontal environmental wells, the variety of horizontal environmental well applications, the types of geologic and hydrogeologic conditions within which horizontal environmental wells have been installed, and the companies that perform horizontal environmental well installations. Other information, such as the cost of horizontal environmental well installations and the results of tests performed on the wells, is not complete but is provided as general information with the caveat that the information should not be used to compare drilling companies. The result of the survey is a catalogue of horizontal environmental wells that are categorized by the objective or use of the wells, the vertical depth of the wells, and the drilling company contracted to install the wells.

  9. Adaptation of primate vestibuloocular reflex to altered peripheral vestibular inputs. II Spatiotemporal properties of the adapted slow-phase eye velocity

    NASA Technical Reports Server (NTRS)

    Angelaki, D. E.; Hess, B. J.

    1996-01-01

    1. The ability of the vestibuloocular reflex (VOR) to undergo adaptive modification after selective changes in the peripheral vestibular system was investigated in rhesus monkeys by recording three-dimensional eye movements before and after inactivation of selective semicircular canals. In the preceding paper we showed that the horizontal VOR gain evoked by passive yaw oscillations after lateral semicircular canal inactivation recovers gradually over time in a frequency-specific manner. Here we present the spatial tuning of the adapted slow-phase eye velocity and describe its spatiotemporal properties as a function of time after canal inactivation. 2. The spatial organization of the VOR was investigated during oscillations at different head positions in the pitch, roll, and yaw planes, as well as in the right anterior/left posterior and left anterior/right posterior canal planes. Acutely after bilateral inactivation of the lateral semicircular canals, a small horizontal response could still be elicited that peaked during rotations in pitched head positions that would maximally stimulate vertical semicircular canals. In addition, the phase of horizontal slow-phase velocity abruptly reversed through 180 degrees at positions close to upright, similarly to torsional slow-phase velocity. These spatial response properties suggest that the small, residual horizontal response components that are present acutely after plugging of both lateral canals originate from vertical semicircular canal signals. 3. As the horizontal response amplitude increased over time, consistent changes were also observed in the spatiotemporal tuning of horizontal slow-phase velocity. 1) The spatiotemporal response properties of horizontal slow-phase velocity acquired noncosine tuning characteristics, primarily in the pitch plane, in the right anterior/left posterior and left anterior/right posterior canal planes. Accordingly, horizontal response amplitude was nonzero during rotation in any head

  10. Adaptation of primate vestibuloocular reflex to altered peripheral vestibular inputs. II Spatiotemporal properties of the adapted slow-phase eye velocity

    NASA Technical Reports Server (NTRS)

    Angelaki, D. E.; Hess, B. J.

    1996-01-01

    1. The ability of the vestibuloocular reflex (VOR) to undergo adaptive modification after selective changes in the peripheral vestibular system was investigated in rhesus monkeys by recording three-dimensional eye movements before and after inactivation of selective semicircular canals. In the preceding paper we showed that the horizontal VOR gain evoked by passive yaw oscillations after lateral semicircular canal inactivation recovers gradually over time in a frequency-specific manner. Here we present the spatial tuning of the adapted slow-phase eye velocity and describe its spatiotemporal properties as a function of time after canal inactivation. 2. The spatial organization of the VOR was investigated during oscillations at different head positions in the pitch, roll, and yaw planes, as well as in the right anterior/left posterior and left anterior/right posterior canal planes. Acutely after bilateral inactivation of the lateral semicircular canals, a small horizontal response could still be elicited that peaked during rotations in pitched head positions that would maximally stimulate vertical semicircular canals. In addition, the phase of horizontal slow-phase velocity abruptly reversed through 180 degrees at positions close to upright, similarly to torsional slow-phase velocity. These spatial response properties suggest that the small, residual horizontal response components that are present acutely after plugging of both lateral canals originate from vertical semicircular canal signals. 3. As the horizontal response amplitude increased over time, consistent changes were also observed in the spatiotemporal tuning of horizontal slow-phase velocity. 1) The spatiotemporal response properties of horizontal slow-phase velocity acquired noncosine tuning characteristics, primarily in the pitch plane, in the right anterior/left posterior and left anterior/right posterior canal planes. Accordingly, horizontal response amplitude was nonzero during rotation in any head

  11. Tooth anatomy risk factors influencing root canal working length accessibility

    PubMed Central

    Tang, Lu; Sun, Tuo-qi; Gao, Xiao-jie; Zhou, Xue-dong; Huang, Ding-ming

    2011-01-01

    The aim of this study was to analyze the specific influence of root canal anatomy on the accessibility of working length during root canal therapy. Four hundred seventy-six root canal therapy cases (amounting to a total of 1 005 root canals) were examined. The anatomy risk factors assessed in each case included: tooth type (tooth location), root canal curvature, and root canal calcification, as well as endodontic retreatment. The investigation examined the correlation between each of these anatomic factors and the working length, with statistical analysis consisting of Chi-square tests and multiple logistic regression analysis. In an independent factor analysis, tooth type (tooth location), root canal curvature, canal calcification, and endodontic retreatment were determined to be the primary risk factors. In a multiple-factor regression model, root curvature and canal calcification were found to most significantly influence root canal working length accessibility (P<0.05). Root canal anatomy increases the difficulty of root canal preparation. Appropriate consideration of tooth anatomy will assist in accurate determination of preparation difficulty before instrumentation. This study alerts clinical therapists to anatomical factors influencing the working length accessibility, and allows for a direct estimate of success rate given in situ measurements of tooth factors during the root canal treatment procedure. PMID:21789962

  12. Root canal debridement: an online study guide.

    PubMed

    2008-05-01

    The Editorial Board of the Journal of Endodontics has developed a literature-based study guide of topical areas related to endodontics. This study guide is intended to give the reader a focused review of the essential endodontic literature and does not cite all possible articles related to each topic. Although citing all articles would be comprehensive, it would defeat the idea of a study guide. This section will present root canal debridement including subdivisions on canal access, canal debridement, orifice enlargement and preflaring, crown-down technique, balanced force, nickel titanium and other shape memory alloys, rotary engine-driven techniques, endodontic instruments, irrigation, electronic apex locators, sonics/ultrasonics, smear layer, and intracanal medicaments.

  13. Dynamic Fracture Properties of Rocks Subjected to Static Pre-load Using Notched Semi-circular Bend Method

    NASA Astrophysics Data System (ADS)

    Chen, Rong; Li, Kang; Xia, Kaiwen; Lin, Yuliang; Yao, Wei; Lu, Fangyun

    2016-10-01

    A dynamic load superposed on a static pre-load is a key problem in deep underground rock engineering projects. Based on a modified split Hopkinson pressure bar test system, the notched semi-circular bend (NSCB) method is selected to investigate the fracture initiation toughness of rocks subjected to pre-load. In this study, a two-dimensional ANSYS finite element simulation model is developed to calculate the dimensionless stress intensity factor. Three groups of NSCB specimen are tested under a pre-load of 0, 37 and 74 % of the maximum static load and with the loading rate ranging from 0 to 60 GPa m1/2 s-1. The results show that under a given pre-load, the fracture initiation toughness of rock increases with the loading rate, resembling the typical rate dependence of materials. Furthermore, the dynamic rock fracture toughness decreases with the static pre-load at a given loading rate. The total fracture toughness, defined as the sum of the dynamic fracture toughness and initial stress intensity factor calculated from the pre-load, increases with the pre-load at a given loading rate. An empirical equation is used to represent the effect of loading rate and pre-load force, and the results show that this equation can depict the trend of the experimental data.

  14. Static and free-vibrational response of semi-circular graphite-epoxy frames with thin-walled open sections

    NASA Technical Reports Server (NTRS)

    Collins, J. Scott; Johnson, Eric R.

    1989-01-01

    Experiments were conducted to measure the three-dimensional static and free vibrational response of two graphite-epoxy, thin-walled, open section frames. The frames are semi-circular with a radius of three feet, and one specimen has an I cross section and the other has a channel cross section. The flexibility influence coefficients were measured in static tests for loads applied at midspan with the ends of the specimens clamped. Natural frequencies and modes were determined from vibrational tests for free and clamped end conditions. The experimental data is used to evaluate a new finite element which was developed specifically for the analysis of curved, thin-walled structures. The formulation of the element is based on a Vlasov-type, thin-walled, curved beam theory. The predictions from the finite element program generally correlated well with the experimental data for the symmetric I-specimen. Discrepancies in some of the data were found to be due to flexibility in the clamped end conditions. With respect to the data for the channel specimen, the correlation was less satisfactory. The finite element analysis predicted the out-of-plane response of the channel specimen reasonably well, but large discrepancies occurred between the predicted in-plane response and the experimental data. The analysis predicted a much more compliant in-plane response than was observed in the experiments.

  15. Spectral element simulations of unsteady flow over a 3D, low aspect-ratio semi-circular wing

    NASA Astrophysics Data System (ADS)

    Kandala, Sriharsha; Rempfer, Dietmar

    2011-11-01

    Numerical simulations of unsteady 3D flow over a low-aspect-ratio semi-circular wing are performed using a spectral element method. Specsolve, a parallel spectral element solver currently under development at IIT, is used for the simulation. The solution is represented locally as a tensor product of Legendre polynomials and C0-continuity is enforced between adjacent domains. A BDF/EXT scheme is used for temporal integration. The fractional step method is used for computing velocity and pressure. The code incorporates a FDM (fast diagonalization method) based overlapping Schwarz preconditioner for the consistent Poisson operator and an algebraic multigrid based coarse grid solver (P.F. Fischer et al, J. Phys.: Conf. Ser.(125) 012076, 2008) for pressure. The simulation replicates the conditions of the active flow control experiment (D. Williams et al, AIAA paper, 2010-4969). The Reynolds number based on chord length and free-stream velocity is about 68000. Different angles of attack, encompassing both pre-stall and post-stall regimes, are considered. These results are compared with data from the experiment and numerical simulations based on Lattice Boltzmann method (G. Brès et al, AIAA paper, 2010-4713).

  16. Portable Horizontal-Drilling And Positioning Device

    NASA Technical Reports Server (NTRS)

    Smigocki, Edmund; Johnson, Clarence

    1988-01-01

    Portable horizontal-drilling and positioning device, constructed mainly of off-the-shelf components, accurately drills horizontal small holes in irregularly shaped objects. Holes precisely placed and drilled in objects that cannot be moved to shop area. New device provides three axes of movement while maintaining horizontal drilling.

  17. Accurate Measurement of Canal Length during Root Canal Treatment: An In Vivo Study

    PubMed Central

    Sadaf, Durre; Ahmad, Muhammad Zubair

    2015-01-01

    Objectives: To assess the consistency and accuracy of Electronic Apex Locator (EAL) (Root ZXII) in individual canals and its association with other clinical variables. Study Design: Cross-Sectional study. Place of study: Dental section of the Aga Khan University Hospital, Karachi, Pakistan. Materials and Methods: Working length was measured by EAL in 180 patients requiring endodontic therapy in molar and premolar teeth. The effects of clinical variables e.g. gender and pulpal status on the consistency and accuracy of EAL were recorded. Performance of apex locator was considered “Consistent” when the scale bar was stable and moved only in correspondence to the movement of file in the root canal. Accuracy was determined by inserting the file at the working length determined by the EAL and periapical view of radiograph was taken using paralleling technique. Estimated working length was considered accurate when the file tip was located 0-2mm short of the radiographic apex. If the file was overextended from the radiographic apex, it showed dysfunction of the EAL. Results: Consistency of EAL was found 97.6% in distobuccal canals, 91.1% in palatal canals, 73.7% in mesiolingual canals, 83.3% in mesiobuccal and 80.2% in distal canals. Accuracy of EAL was 91.4% in mesiolingual canal, 92% in mesiobuccal, and 90.2% in Palatal and 93.2% in distal canal. Conclusion: Consistency of electronic apex locator vary in different canals, however consistent measurements are highly accurate. No significant association was found between other clinical variables with the consistency and accuracy of EAL.

  18. Polyacrylamide Transport in Water Delivery Canals

    NASA Astrophysics Data System (ADS)

    Chen, L.; Zhu, J.; Young, M.

    2007-12-01

    Linear, anionic polyacrylamide (PAM) is being considered in the western United States as a technology to reduce seepage in unlined water delivery canals. A broad laboratory and field testing program has been undertaken to understand the benefits and potential environmental impacts of PAM use. The ability to predict the fate and transport of PAM in water delivery canals could prove to be a useful planning tool for PAM application. However, one key area of uncertainty of this type of canal treatment is the hydration, reaction, and settling rates of PAM after the dry powder is added to the canal water. In this study, we have developed a model that incorporates a number of known physical and chemical processes that can affect PAM transport, such as convection, dispersion, dissolution, flocculation, and settling, while solving the governing convection-dispersion transport equation. The model uses a mixed analytical and advanced numerical approach, and implements a transient partitioning of PAM mass between the canal water, the substrate soil, and potentially to open water bodies downstream of the application point. All source terms are modeled based on physical and chemical mechanisms as well as laboratory or field determined parameters. To more closely simulate field treatment of some canals, where PAM application moves upstream in time, the model is capable of implementing either a fixed or mobile upper boundary. In the latter treatment, the PAM can be added discretely or continuously in both time and space. A number of test situations have been simulated thus far, including theoretical and hypothetical cases for a wide range of conditions. The model also performed well when predicting PAM concentrations from a full-scale canal treatment experiment. The model provides a useful tool for predicting PAM fate and transport in water delivery canals, and therefore can play an important role in evaluating the efficacy of PAM application for water resources management

  19. Plasmon canalization and tunneling over anisotropic metasurfaces

    NASA Astrophysics Data System (ADS)

    Correas-Serrano, Diego; Alù, Andrea; Gomez-Diaz, J. Sebastian

    2017-08-01

    We discuss the possibility of plasmon canalization, collimation, and tunneling over ultrathin metasurfaces, enabled by extreme anisotropy in their complex conductivity dyadic. The interplay between anisotropy, conductivity-near-zero, and loss is exploited here to derive general conditions for plasmon canalization and efficient energy transport. We also demonstrate how the intrinsic in-plane anisotropy of black phosphorus can provide a natural platform to engineer these conditions, exhibiting important advantages over isotropic plasmonic materials. Our findings have implications for plasmonic sensors, planar hyperlenses, and plasmon steering over a surface, and they highlight the potential of two-dimensional materials beyond graphene.

  20. Bitter Root Irrigation district canal, looking east, typical section and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Bitter Root Irrigation district canal, looking east, typical section and crossing - Bitter Root Irrigation Project, Bitter Root Irrigation Canal, Heading at Rock Creek Diversion Dam, West of U.S. Highway 93, Darby, Ravalli County, MT

  1. MAIN CANAL HEADWORKS, FROM DOWNSTREAM (TO RIGHT), NOTE SAND AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    MAIN CANAL HEADWORKS, FROM DOWNSTREAM (TO RIGHT), NOTE SAND AND SILT SLUICE GATE FOR DIVERSION DAM ON LEFT, VIEW TO NORTHWEST - Salmon Creek Diversion Dam, Main Canal Headworks, Salmon Creek, Okanogan, Okanogan County, WA

  2. 58. View of lined canal looking west from road bridge ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    58. View of lined canal looking west from road bridge crossing lined canal. Photo by Brian C. Morris, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  3. 1. LOOKING WEST ON LEHIGH CANAL, GRAPHITE MILL IN FOREGROUND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. LOOKING WEST ON LEHIGH CANAL, GRAPHITE MILL IN FOREGROUND - Pettinos Brothers Graphite Manufacturing Mill, On Sand Island, south side of Lehigh Canal, west of Hill-to-Hill Bridge, Bethlehem, Northampton County, PA

  4. 1. General view from south side of Canal Street showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. General view from south side of Canal Street showing silos at southeast corner of side; view to northwest. - Champion-International Paper Company, Clay Storage Silos, West bank of Spicket River at Canal Street, Lawrence, Essex County, MA

  5. 31. Floating original Ship Canal draw (in background) to University ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. Floating original Ship Canal draw (in background) to University Heights location. New Ship Canal draw in foreground. June 1906 photograph. - University Heights Bridge, Spanning Harlem River at 207th Street & West Harlem Road, New York County, NY

  6. 19. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING NORTHEAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING NORTHEAST FROM 56TH STREET, August 1989 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

  7. 26. VIEW OF THE PEDESTRIAN BRIDGE CROSSING GRAND CANAL AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. VIEW OF THE PEDESTRIAN BRIDGE CROSSING GRAND CANAL AT 30TH STREET IN PHOENIX, LOOKING WEST, Photographer: Mark Durben, April 1989 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  8. 21. VIEW OF GRAND CANAL, SHOWING OLD ALIGNMENT, LOOKING WEST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    21. VIEW OF GRAND CANAL, SHOWING OLD ALIGNMENT, LOOKING WEST LOCATION UNKNOWN. THE WIDE DRY BED OF THE SALT RIVER SPANS THE BACKGROUND. Photographer: Mark Durben, April 1989 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  9. 10. Tempe Canal, looking south from Apache Boulevard, showing new ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Tempe Canal, looking south from Apache Boulevard, showing new apartments and old farm silos. Photographer: Mark Durben, February 1989. Source: SRPA - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

  10. 20. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING SOUTHEAST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING SOUTHEAST FROM 56TH STREET, August 1989 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

  11. 6. Tempe Crosscut Canal, looking west from Division Gates. Lateral ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Tempe Crosscut Canal, looking west from Division Gates. Lateral at left is for local delivery of irrigation water. Photographer: Mark Durben, February 1989. Source: SRPA - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

  12. 17. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING SOUTH FROM GROVE PARKWAY, August 1989 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

  13. 18. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. VIEW OF SOUTHERN BRANCH OF HIGHLINE CANAL, LOOKING SOUTH TOWARD ELLIOT ROAD, August 1989 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

  14. 32. VIEW OF TERMINUS OF GRAND CANAL, SHOWING TURNOUT GATES, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. VIEW OF TERMINUS OF GRAND CANAL, SHOWING TURNOUT GATES, LOOKING SOUTHWEST. WASTE WATER IS TURNED INTO THE BED OF NEW RIVER. Photographer: Mark Durben, April 1989 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  15. 31. VIEW SHOWING DEMOSSING ALONG GRAND CANAL. THE DRAGLINE SCOOPS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. VIEW SHOWING DEMOSSING ALONG GRAND CANAL. THE DRAGLINE SCOOPS UP AQUATIC WEEDS AND DEPOSITS THEM IN A DUMP TRUCK. Photographer: Mark Durben, April 1989 - Grand Canal, North side of Salt River, Tempe, Maricopa County, AZ

  16. 2. LOOKING DOWN THE LINED POWER CANAL AS IT WINDS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. LOOKING DOWN THE LINED POWER CANAL AS IT WINDS ITS WAY TOWARD THE CEMENT MILL Photographer: Walter J. Lubken, November 19, 1907 - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

  17. 1. Photocopy of photograph. ORIGINAL CANAL COAL POCKETS Source: Delaware ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Photocopy of photograph. ORIGINAL CANAL COAL POCKETS Source: Delaware and Hudson Railroad and Canal, by Wayne County Historical Society. - Honesdale Coal Pockets, Main & Commercial Streets, between 700 & 800 blocks, Honesdale, Wayne County, PA

  18. 12. VIEW OF GAGE IRRIGATION CANAL AT HILLTOP DRIVE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. VIEW OF GAGE IRRIGATION CANAL AT HILLTOP DRIVE AND BARTON ROAD SHOWING BEGINNING OF SIPHON, DATED '1952' - Gage Irrigation Canal, Running from Santa Ana River to Arlington Heights, Riverside, Riverside County, CA

  19. 4. VIEW LOOKING NORTH OF SAN TAN INDIAN CANAL WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW LOOKING NORTH OF SAN TAN INDIAN CANAL WITH NEWER CHECK AND TURNOUT STRUCTURE IN FOREGROUND - San Carlos Irrigation Project, San Tan Indian Canal, North of Gila River, Coolidge, Pinal County, AZ

  20. 12. CONCRETE DROP STRUCTURE ON NORTH SIDE CANAL WITH TWO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. CONCRETE DROP STRUCTURE ON NORTH SIDE CANAL WITH TWO TURNOUTS IN BACKGROUND, T4S R7E S24. VIEW LOOKING EAST - San Carlos Irrigation Project, North Side Canal, North of Gila River, Coolidge, Pinal County, AZ