Interactions between Auditory and Vestibular Modalities during Stimulation with a Combined Vestibular and Cochlear Prosthesis

Background: A combined vestibular and cochlear prosthesis may restore hearing and balance to patients who have lost both. To do so, the device should activate each sensory system independently. Objectives: In this study, we quantify auditory and vestibular interactions during interleaved stimulation with a combined 16-channel cochlear and 6-channel vestibular prosthesis in human subjects with both hearing and vestibular loss. Methods: Three human subjects were implanted with a combined vestibular and cochlear implant. All subjects had severe-to-profound deafness in the implanted ear. We provided combined stimulation of the cochlear and vestibular arrays and looked for interactions between these separate inputs. Our main outcome measures were electrically evoked slow-phase eye velocities during nystagmus elicited by brief trains of biphasic pulse stimulation of the vestibular end organs with and without concurrent stimulation of the cochlea, and Likert scale assessments of perceived loudness and pitch during stimulation of the cochlea, with and without concurrent stimulation of the vestibular ampullae. Results: All subjects had no auditory sensation resulting from semicircular canal stimulation alone, and no sensation of motion or slow-phase eye movement resulting from cochlear stimulation alone. However, interleaved cochlear stimulation did produce changes in the slow-phase eye velocities elicited by electrical stimulation. Similarly, interleaved semicircular canal stimulation did elicit changes in the perceived pitch and loudness resulting from stimulation at multiple sites in the cochlea. Conclusions: There are significant interactions between different sensory modalities during stimulation with a combined vestibular and cochlear prosthesis. Such interactions present potential challenges for stimulation strategies to simultaneously restore auditory and vestibular function with such an implant.

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

Journal of Neurophysiology ◽

10.1152/jn.00171.2013 ◽

2015 ◽

Vol 113 (10) ◽

pp. 3866-3892 ◽

Cited By ~ 35

Author(s):

James O. Phillips ◽

Leo Ling ◽

Kaibao Nie ◽

Elyse Jameyson ◽

Christopher M. Phillips ◽

...

Keyword(s):

Electrical Stimulation ◽

Eye Movements ◽

Human Subjects ◽

Vestibular Function ◽

Slow Phase ◽

Vestibular Loss ◽

Stimulation Current ◽

Eye Velocity ◽

Over Time ◽

Stimulation Of

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.

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Pulse-step-sine rotation test for the identification of abnormal vestibular function

Journal of Vestibular Research ◽

10.3233/ves-2005-155-606 ◽

2005 ◽

Vol 15 (5-6) ◽

pp. 291-311

Author(s):

Robert J. Peterka

Keyword(s):

Human Subjects ◽

Vestibular Function ◽

Semicircular Canals ◽

Large Change ◽

Sine Wave ◽

Slow Phase ◽

Vestibular Loss ◽

Bilateral Vestibular Loss ◽

Discharge Rates ◽

Response Measures

This study illustrates the use of a novel "pulse-step-sine" (PSS) rotational stimulus to identify abnormal function of the horizontal semicircular canals in human subjects with unilateral and bilateral vestibular deficits. The cyclic PSS stimulus includes a "bias component" and a "probe component". The bias component, consisting of a short duration pulse of acceleration followed by an acceleration step, is designed to produce a large change in canal afferent discharge rates that silences the neural activity in one canal during the step portion of the PSS stimulus. The pulse and step components are then repeated with opposite sign to silence afferent activity in the opposite canal. The probe component, consisting of a ∼1 Hz sine wave superimposed on the step portions of the stimulus, is designed to test the ability of canal afferents in the excited canal to encode the probe stimulus. Various response measures are developed that characterize the horizontal slow phase eye movements evoked by the PSS stimulus. Results show that these measures can distinguish subjects with normal vestibular function from those with unilateral and bilateral vestibular loss, can identify the side-of-lesion in subjects with well compensated unilateral vestibular loss, and can possibly identify the side-of-greater-loss in subjects with asymmetric bilateral loss.

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Skull Vibration-Induced Nystagmus Test in a Human Model of Horizontal Canal Plugging

Audiology Research ◽

10.3390/audiolres11030028 ◽

2021 ◽

Vol 11 (3) ◽

pp. 301-312

Author(s):

Georges Dumas ◽

Christol Fabre ◽

Anne Charpiot ◽

Lea Fath ◽

Hella Chaney-Vuong ◽

...

Keyword(s):

Semicircular Canal ◽

Vestibular Function ◽

Human Model ◽

Vestibular Evoked Myogenic Potentials ◽

Head Impulse Test ◽

Slow Phase ◽

Caloric Test ◽

Horizontal Semicircular Canal ◽

Horizontal Canal ◽

Tertiary Referral Center

Background/Aim: the aim of this study was to assess the skull vibration-induced nystagmus test (SVINT) results and vestibular residual function after horizontal semicircular canal (HSCC) plugging. Methods: In this retrospective chart review performed in a tertiary referral center, 11 patients who underwent unilateral horizontal semicircular canal plugging (uHSCCP) for disabling Menière’s disease (MD) were included. The skull vibration-induced nystagmus (SVIN) slow-phase velocity (SPV) was compared with the results of the caloric test (CaT), video head impulse test (VHIT), and cervical vestibular-evoked myogenic potentials (cVEMP) performed on the same day. Results: Overall, 10 patients had a strong SVIN beating toward the intact side (Horizontal SVIN-SPV: 8.8°/s ± 5.6°/s), 10 had a significant or severe ipsilateral CaT hypofunction, 10 had an ipsilateral horizontal VHIT gain impairment, and 3 had altered cVEMP on the operated side. Five had sensorineural hearing worsening. SVIN-positive results were correlated with CaT and horizontal VHIT (HVHIT) results (p < 0.05) but not with cVEMP. SVIN-SPV was correlated with CaT hypofunction in % (p < 0.05). Comparison of pre- and postoperative CaT % hypofunction showed a significant worsening (p = 0.028). Conclusion: SVINT results in a human model of horizontal canal plugging are well correlated with vestibular tests exploring horizontal canal function, but not with cVEMP. SVINT always showed a strong lesional nystagmus beating away from the lesion side. SVIN acts as a good marker of HSCC function. This surgical technique showed invasiveness regarding horizontal canal vestibular function.

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Use of a visual guide to improve the quality of VOR responses evoked by high-velocity rotational stimuli

Journal of Vestibular Research ◽

10.3233/ves-2008-18102 ◽

2008 ◽

Vol 18 (1) ◽

pp. 15-24

Author(s):

Claire C. Gianna-Poulin ◽

Robert J. Peterka

Keyword(s):

High Velocity ◽

Human Subjects ◽

Vestibular Function ◽

Slow Phase ◽

Velocity Data ◽

Healthy Human ◽

Diagnostic Measures ◽

Ocular Reflex ◽

Vestibulo Ocular Reflex

High-velocity rotational stimuli have the potential to improve the diagnostic capabilities of clinical rotation testing by revealing nonlinear vestibulo-ocular reflex (VOR) responses that are indicative of asymmetric vestibular function. However, eye movements evoked by high-velocity rotations often are inconsistent over time and therefore do not yield reliable diagnostic measures. This study investigated whether use of a novel "visual guide" could improve the consistency and quality of VORs obtained during testing with pulse-step-sine (PSS) stimuli providing periodic high-velocity, horizontal-plane rotations with peak velocities up to 290 deg/s. The visual guide (narrow phosphorescent line spanning 180° field of view) was mounted horizontally on the rotation chair at the subject's eye level. Eight healthy human subjects were tested either in complete darkness while performing an alerting task, or while viewing the visual guide in an otherwise dark room. We found that the visual guide improved the quality of VOR responses as shown by an increased proportion of slow-phase velocity data segments retained for analysis, by a decreased variance of the processed eye velocity data, and by a reduction of outlying VOR response measures. We also found that the visual guide did not induce visual suppression because VOR gain measures were not diminished.

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Vestibular Function and Motion Sickness Susceptibility: Videonystagmographic Evidence From Oculomotor and Caloric Tests

American Journal of Audiology ◽

10.1044/2020_aja-19-00050 ◽

2020 ◽

Vol 29 (2) ◽

pp. 188-198

Author(s):

Cynthia G. Fowler ◽

Margaret Dallapiazza ◽

Kathleen Talbot Hadsell

Keyword(s):

Phase Velocity ◽

Motion Sickness ◽

Repeated Measures ◽

Short Form ◽

Vestibular Function ◽

Slow Phase ◽

Test Results ◽

Normal Range ◽

Slow Phase Velocity ◽

Caloric Tests

Purpose Motion sickness (MS) is a common condition that affects millions of individuals. Although the condition is common and can be debilitating, little research has focused on the vestibular function associated with susceptibility to MS. One causal theory of MS is an asymmetry of vestibular function within or between ears. The purposes of this study, therefore, were (a) to determine if the vestibular system (oculomotor and caloric tests) in videonystagmography (VNG) is associated with susceptibility to MS and (b) to determine if these tests support the theory of an asymmetry between ears associated with MS susceptibility. Method VNG was used to measure oculomotor and caloric responses. Fifty young adults were recruited; 50 completed the oculomotor tests, and 31 completed the four caloric irrigations. MS susceptibility was evaluated with the Motion Sickness Susceptibility Questionnaire–Short Form; in this study, percent susceptibility ranged from 0% to 100% in the participants. Participants were divided into three susceptibility groups (Low, Mid, and High). Repeated-measures analyses of variance and pairwise comparisons determined significance among the groups on the VNG test results. Results Oculomotor test results revealed no significant differences among the MS susceptibility groups. Caloric stimuli elicited responses that were correlated positively with susceptibility to MS. Slow-phase velocity was slowest in the Low MS group compared to the Mid and High groups. There was no significant asymmetry between ears in any of the groups. Conclusions MS susceptibility was significantly and positively correlated with caloric slow-phase velocity. Although asymmetries between ears are purported to be associated with MS, asymmetries were not evident. Susceptibility to MS may contribute to interindividual variability of caloric responses within the normal range.

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Vestibular semicircular canal function as detected by video Head Impulse Test (vHIT) is essentially unchanged in people with Parkinson’s disease compared to healthy controls

Journal of Vestibular Research ◽

10.3233/ves-201626 ◽

2021 ◽

pp. 1-9

Author(s):

Kim E. Hawkins ◽

Elodie Chiarovano ◽

Serene S. Paul ◽

Ann M Burgess ◽

Hamish G. MacDougall ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Semicircular Canal ◽

Neurodegenerative Disorder ◽

Vestibular Function ◽

Head Impulse Test ◽

Healthy Controls ◽

Video Head Impulse Test ◽

Head Impulse ◽

Vestibulo Ocular Reflex

BACKGROUND: Parkinson’s disease (PD) is a common multi-system neurodegenerative disorder with possible vestibular system dysfunction, but prior vestibular function test findings are equivocal. OBJECTIVE: To report and compare vestibulo-ocular reflex (VOR) gain as measured by the video head impulse test (vHIT) in participants with PD, including tremor dominant and postural instability/gait dysfunction phenotypes, with healthy controls (HC). METHODS: Forty participants with PD and 40 age- and gender-matched HC had their vestibular function assessed. Lateral and vertical semicircular canal VOR gains were measured with vHIT. VOR canal gains between PD participants and HC were compared with independent samples t-tests. Two distinct PD phenotypes were compared to HC using Tukey’s ANOVA. The relationship of VOR gain with PD duration, phenotype, severity and age were investigated using logistic regression. RESULTS: There were no significant differences between groups in vHIT VOR gain for lateral or vertical canals. There was no evidence of an effect of PD severity, phenotype or age on VOR gains in the PD group. CONCLUSION: The impulsive angular VOR pathways are not significantly affected by the pathophysiological changes associated with mild to moderate PD.

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