The Influence of Unilateral Horizontal Semicircular Canal Plugs on the Horizontal Vestibulo-Ocular Reflex of the Rabbit

1981 ◽  
pp. 231-239 ◽  
Author(s):  
N. H. Barmack ◽  
V. E. Pettorossi
Keyword(s):  
Semicircular Canal ◽  
Horizontal Semicircular Canal ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

Effect of Spatial Orientation of the Horizontal Semicircular Canal on the Vestibulo-Ocular Reflex

2017 ◽  
Vol 38 (2) ◽  
pp. 239-243 ◽  
Author(s):  
Rebecca Maxwell ◽  
Constantin von Kirschbaum ◽  
Claudia Jerin ◽  
Nadine Lehnen ◽  
Eike Krause ◽  
...  
Keyword(s):  
Spatial Orientation ◽  
Semicircular Canal ◽  
Horizontal Semicircular Canal ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

Implications of Ewald's Second Law for the Evaluation of Vestibular Function

1979 ◽  
Vol 87 (4) ◽  
pp. 453-458 ◽  
Author(s):  
Young S. Kim ◽  
Clifford G. Y. Lau ◽  
Herman A. Jenkins ◽  
Vicente Honrubia
Keyword(s):  
Vestibular System ◽  
Semicircular Canal ◽  
Piecewise Linear ◽  
Vestibular Function ◽  
Second Law ◽  
Horizontal Semicircular Canal ◽  
Transfer Characteristics ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Ewald’S Second Law

The significance of Ewald's second law in the evaluation of the vestibulo-ocular reflex (VOR) was Investigated using the transfer characteristics of the vestibular and VOR systems in normal rabbits and rabbits in which one horizontal semicircular canal had been blocked. The transfer characteristics of the vestibular system were derived from the experimental results reported by Goldberg and Fernandez in 1971. A comparison was made of the properties of the bilateral and monolateral VOR systems with the predictions of a piecewise linear model of the vestibular system. The data received quantitatively collaborate the prediction of Ewald's second law as ft applies to the VOR responses.

Clinical Validity of Quantified Visually Enhanced Vestibulo-ocular Reflex Test to Detect Horizontal Semicircular Canal Hypofunction

2019 ◽  
Vol 40 (3) ◽  
pp. 365-371 ◽  
Author(s):  
Jorge Rey-Martinez ◽  
Elisabeth Ninchritz ◽  
Idoia Palicio ◽  
Miren Goiburu ◽  
Carmen Maria Casado ◽  
...  
Keyword(s):  
Semicircular Canal ◽  
Clinical Validity ◽  
Horizontal Semicircular Canal ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

Torsional vestibulo-ocular reflex during whole-body oscillation in the upright and the supine position: II. Responses in patients after vestibular neuritis

2004 ◽  
Vol 14 (4) ◽  
pp. 353-359
Author(s):  
A. Schmid-Priscoveanu ◽  
A.A. Kori ◽  
D. Straumann
Keyword(s):  
Supine Position ◽  
Semicircular Canal ◽  
Low Frequency ◽  
Phase Changes ◽  
Vestibular Neuritis ◽  
Whole Body ◽  
Healthy Human ◽  
Phase Lead ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

In a recent study we demonstrated that otolith input modifies the torsional angular vestibulo-ocular reflex (torVOR) of healthy human subjects: Compared to turntable oscillations in supine position, oscillations in upright position increased the gain of torVOR by 0.1 and cancelled the phase lead originating from low-frequency semicircular canal signals. We asked whether these otolith-related changes of torVOR are still present in patients after vestibular neuritis (VN). Eight patients were sinusoidally oscillated about their naso-occipital axis in supine (canal-only stimulation) and upright (canal-and-otolith stimulation) position. Three-dimensional eye movements were recorded with dual search coils. The patients showed similar otolith-related gain and phase changes of the torVOR as healthy subjects: the gain increased by about 0.1 (p < 0.05) and the low-frequency phase lead from semicircular canal signals was abolished. These results indicate that otolith function after VN is still sufficient to interact with semicircular canal signals to optimize torsional gaze stabilization when the head is upright.

The click-evoked vestibulo-ocular reflex in superior semicircular canal dehiscence

Neurology ◽  
2003 ◽  
Vol 60 (7) ◽  
pp. 1172-1175 ◽  
Author(s):  
G.M. Halmagyi ◽  
L. A. McGarvie ◽  
S. T. Aw ◽  
R. A. Yavor ◽  
M. J. Todd
Keyword(s):  
Semicircular Canal ◽  
Superior Semicircular Canal Dehiscence ◽  
Superior Semicircular Canal ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Canal Dehiscence

Click-evoked vestibulo-ocular reflex

Neurology ◽  
2006 ◽  
Vol 66 (7) ◽  
pp. 1079-1087 ◽  
Author(s):  
S. T. Aw ◽  
M. J. Todd ◽  
G. E. Aw ◽  
J. S. Magnussen ◽  
I. S. Curthoys ◽  
...  
Keyword(s):  
Semicircular Canal ◽  
Rotation Axis ◽  
Head Orientation ◽  
Superior Canal Dehiscence ◽  
Ocular Reflex ◽  
Eye Rotation ◽  
Vestibulo Ocular Reflex ◽  
Low Threshold ◽  
Canal Dehiscence ◽  
Click Polarity

Background: An enlarged, low-threshold click-evoked vestibulo-ocular reflex (VOR) can be averaged from the vertical electro-oculogram in a superior canal dehiscence (SCD), a temporal bone defect between the superior semicircular canal and middle cranial fossa.Objective: To determine the origin and quantitative stimulus–response properties of the click-evoked VOR.Methods: Three-dimensional, binocular eye movements evoked by air-conducted 100-microsecond clicks (110 dB normal hearing level, 145 dB sound pressure level, 2 Hz) were measured with dual-search coils in 11 healthy subjects and 19 patients with SCD confirmed by CT imaging. Thresholds were established by decrementing loudness from 110 dB to 70 dB in 10-dB steps. Eye rotation axis of click-evoked VOR computed by vector analysis was referenced to known semicircular canal planes. Response characteristics were investigated with regard to enhancement using trains of three to seven clicks with 1-millisecond interclick intervals, visual fixation, head orientation, click polarity, and stimulation frequency (2 to 15 Hz).Results: In subjects and SCD patients, click-evoked VOR comprised upward, contraversive-torsional eye rotations with onset latency of approximately 9 milliseconds. Its eye rotation axis aligned with the superior canal axis, suggesting activation of superior canal receptors. In subjects, the amplitude was less than 0.01°, and the magnitude was less than 3°/second; in SCD, the amplitude was up to 60 times larger at 0.66°, and its magnitude was between 5 and 92°/second, with a threshold 10 to 40 dB below normal (110 dB). The click-evoked VOR magnitude was enhanced approximately 2.5 times with trains of five clicks but was unaffected by head orientation, visual fixation, click polarity, and stimulation frequency up to 10 Hz; it was also present on the surface electro-oculogram.Conclusion: In superior canal dehiscence, clicks evoked a high-magnitude, low-threshold, 9-millisecond-latency vestibulo-ocular reflex that aligns with the superior canal, suggesting superior canal receptor hypersensitivity to sound.

scholarly journals Vestibulo-Ocular Reflex Function in Adolescents With Sport-Related Concussion: Preliminary Results

2019 ◽  
Vol 11 (6) ◽  
pp. 479-485 ◽  
Author(s):  
Abdulaziz A. Alkathiry ◽  
Anthony P. Kontos ◽  
Joseph M. Furman ◽  
Susan L. Whitney ◽  
Eric R. Anson ◽  
...  
Keyword(s):  
Vestibular System ◽  
Rank Order ◽  
Head Impulse Test ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Horizontal Semicircular Canal ◽  
Head Impulse ◽  
Ocular Reflex ◽  
Impulse Function ◽  
Vestibulo Ocular Reflex

Background: Oculomotor impairments, dizziness, and imbalance are common after sports-related concussion (SRC) in adolescents and suggest a relationship between SRC and vestibular system dysfunction. However, it is not clear whether the source of these problems is attributable to the peripheral or central vestibular system. Hypothesis: The video Head Impulse Test (vHIT), which assesses peripheral vestibular function, will show differences in gain between adolescents with and without SRC. Furthermore, there will be an association between vHIT and clinical balance and vestibular/oculomotor testing. Study Design: Cross-sectional study. Level of Evidence: Level 2. Methods: Twenty-five symptomatic adolescents aged between 12 and 19 years with a recent (within 10 days) SRC and 22 healthy controls aged 13 to 20 years were assessed using the vHIT, Balance Error Scoring System (BESS), and Vestibular Ocular Motor Screening (VOMS) tools. The vestibulo-ocular reflex (VOR) gain was calculated independently for right and left head impulses. Independent-samples t tests or Mann-Whitney U tests for nonnormal distributions were used to compare concussed patients and controls on the measures. Spearman rank-order correlations were used to assess the association of vHIT with BESS and VOMS. Results: VOR gain in all adolescents with SRC was greater than 0.8, which is considered within normal limits. VOR gain and BESS scores were not significantly different between groups. Adolescents with SRC had significantly worse VOMS item scores than adolescents without SRC ( P < 0.001). There were no significant correlations among vHIT gain and VOMS or BESS. Conclusion: There was no evidence for dysfunction in the peripheral horizontal semicircular canal function at high rotation speeds (ie, vHIT) after SRC, and vHIT was unrelated to balance and vestibular/oculomotor symptoms and dysfunction. However, adolescents with SRC scored worse on vestibular and oculomotor testing than those without SRC. Vestibular dysfunction and symptoms after SRC may be centrally derived. Clinical Relevance: We do not recommend the assessment of head impulse function in adolescents with SRC unless more definitive signs of peripheral vestibular injury are present. We recommend using the VOMS to assess symptoms of suspected SRC injury in adolescents.

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