scholarly journals Restoring the High-Frequency Dynamic Visual Acuity with a Vestibular Implant Prototype in Humans

2019 ◽  
Vol 25 (Suppl. 1-2) ◽  
pp. 91-95 ◽  
Author(s):  
Dmitrii Starkov ◽  
Nils Guinand ◽  
Florence Lucieer ◽  
Maurizio Ranieri ◽  
Samuel Cavuscens ◽  
...  
Keyword(s):  
Visual Acuity ◽  
High Frequency ◽  
Horizontal Plane ◽  
Head Impulse Test ◽  
Dynamic Visual Acuity ◽  
Bilateral Vestibulopathy ◽  
Vestibular Implant ◽  
Functional Benefit ◽  
Head Impulses ◽  
Near Future

Introduction: The vestibular implant could become a clinically useful device in the near future. This study investigated the feasibility of restoring the high-frequency dynamic visual acuity (DVA) with a vestibular implant, using the functional Head Impulse Test (fHIT). Methods: A 72-year-old female, with bilateral vestibulopathy and fitted with a modified cochlear implant incorporating three vestibular electrodes (MED-EL, Innsbruck, Austria), was available for this study. Electrical stimulation was delivered with the electrode close to the lateral ampullary nerve in the left ear. The high-frequency DVA in the horizontal plane was tested with the fHIT. After training, the patient underwent six trials of fHIT, each with a different setting of the vestibular implant: (1) System OFF before stimulation; (2) System ON, baseline stimulation; (3) System ON, reversed stimulation; (4) System ON, positive stimulation; (5) System OFF, without delay after stimulation offset; and (6) System OFF, 25 min delay after stimulation offset. The percentage of correct fHIT scores for right and left head impulses were compared between trials. Results: Vestibular implant stimulation improved the high-frequency DVA compared to no stimulation. This improvement was significant for “System ON, baseline stimulation” (p = 0.02) and “System ON, positive stimulation” (p < 0.001). fHIT scores changed from 19 to 44% (no stimulation) to maximum 75–94% (System ON, positive stimulation). Conclusion: The vestibular implant seems capable of improving the high-frequency DVA. This functional benefit of the vestibular implant illustrates again the feasibility of this device for clinical use in the near future.

scholarly journals Clinical dynamic visual acuity in patients with cerebellar ataxia and vestibulopathy

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0255299
Author(s):  
Michaela Dankova ◽  
Jaroslav Jerabek ◽  
Dylan J. Jester ◽  
Alena Zumrova ◽  
Jaroslava Paulasova Schwabova ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Vestibular Function ◽  
Head Impulse Test ◽  
Dynamic Visual Acuity ◽  
Bilateral Vestibulopathy ◽  
Caloric Irrigation ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Cerebellar Ataxias ◽  
Central Adaptation

Deterioration of dynamic visual acuity (DVA) as a result of impaired vestibulo-ocular reflex (VOR) has been well described in peripheral vestibulopathies, however, changes in DVA in patients with degenerative cerebellar ataxias (CA) and its relation to VOR impairment in these patients has not yet been evaluated. Our aim was to assess the alterations of DVA in CA and to evaluate its relation to vestibular function. 32 patients with CA and 3 control groups: 13 patients with unilateral and 13 with bilateral vestibulopathy and 21 age matched healthy volunteers were examined by clinical DVA test, VOR was assessed by video Head Impulse Test and caloric irrigation. The severity of ataxia in CA was assessed by Scale for the assessment and rating of ataxia (SARA). Relationship between DVA and vestibular function in CA patients was examined by linear regressions. DVA impairment was highly prevalent in CA patients (84%) and its severity did not differ between CA and bilateral vestibulopathy patients. The severity of DVA impairment in CA was linked mainly to VOR impairment and only marginally to the degree of ataxia. However, DVA impairment was present also in CA patients without significant vestibular lesion showing that central mechanisms such as impairment of central adaptation of VOR are involved. We suggest that the evaluation of DVA should be a standard part of clinical evaluation in patients with progressive CA, as this information can help to target vestibular and oculomotor rehabilitation.

scholarly journals Bilateral vestibulopathy and age: experimental considerations for testing dynamic visual acuity on a treadmill

2020 ◽  
Vol 267 (S1) ◽  
pp. 265-272
Author(s):  
D. Starkov ◽  
M. Snelders ◽  
F. Lucieer ◽  
A. M. L. Janssen ◽  
M. Pleshkov ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Healthy Subjects ◽  
Walking Speed ◽  
Static Condition ◽  
Drop Out ◽  
Dynamic Visual Acuity ◽  
Bilateral Vestibulopathy ◽  
Drop Out Rate ◽  
Visual Acuity Loss ◽  
Walking Speeds

Abstract Introduction Bilateral vestibulopathy (BVP) can affect visual acuity in dynamic conditions, like walking. This can be assessed by testing Dynamic Visual Acuity (DVA) on a treadmill at different walking speeds. Apart from BVP, age itself might influence DVA and the ability to complete the test. The objective of this study was to investigate whether DVA tested while walking, and the drop-out rate (the inability to complete all walking speeds of the test) are significantly influenced by age in BVP-patients and healthy subjects. Methods Forty-four BVP-patients (20 male, mean age 59 years) and 63 healthy subjects (27 male, mean age 46 years) performed the DVA test on a treadmill at 0 (static condition), 2, 4 and 6 km/h (dynamic conditions). The dynamic visual acuity loss was calculated as the difference between visual acuity in the static condition and visual acuity in each walking condition. The dependency of the drop-out rate and dynamic visual acuity loss on BVP and age was investigated at all walking speeds, as well as the dependency of dynamic visual acuity loss on speed. Results Age and BVP significantly increased the drop-out rate (p ≤ 0.038). A significantly higher dynamic visual acuity loss was found at all speeds in BVP-patients compared to healthy subjects (p < 0.001). Age showed no effect on dynamic visual acuity loss in both groups. In BVP-patients, increasing walking speeds resulted in higher dynamic visual acuity loss (p ≤ 0.036). Conclusion DVA tested while walking on a treadmill, is one of the few “close to reality” functional outcome measures of vestibular function in the vertical plane. It is able to demonstrate significant loss of DVA in bilateral vestibulopathy patients. However, since bilateral vestibulopathy and age significantly increase the drop-out rate at faster walking speeds, it is recommended to use age-matched controls. Furthermore, it could be considered to use an individual “preferred” walking speed and to limit maximum walking speed in older subjects when testing DVA on a treadmill.

scholarly journals Bilateral Vestibulopathy: Vestibular Function, Dynamic Visual Acuity and Functional Impact

2018 ◽  
Vol 9 ◽  
Author(s):  
Ruben Hermann ◽  
Eugen C. Ionescu ◽  
Olivier Dumas ◽  
Stephane Tringali ◽  
Eric Truy ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Vestibular Function ◽  
Dynamic Visual Acuity ◽  
Bilateral Vestibulopathy ◽  
Functional Impact

scholarly journals Ethanol consumption impairs vestibulo-ocular reflex function measured by the video head impulse test and dynamic visual acuity

2014 ◽  
Vol 24 (4) ◽  
pp. 289-295 ◽  
Author(s):  
Thomas N. Roth ◽  
Konrad P. Weber ◽  
Vincent G. Wettstein ◽  
Guy B. Marks ◽  
Sally M. Rosengren ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Ethanol Consumption ◽  
Head Impulse Test ◽  
Video Head Impulse Test ◽  
Dynamic Visual Acuity ◽  
Head Impulse ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

Oscillopsia in Patients with Loss of Vestibular Function

1993 ◽  
Vol 109 (1) ◽  
pp. 120-125 ◽  
Author(s):  
Sanjay A. Bhansali ◽  
Charles W. Stockwell ◽  
Dennis I. Bojrab
Keyword(s):  
Visual Acuity ◽  
High Frequency ◽  
Treatment Strategies ◽  
Vestibular Function ◽  
Test Results ◽  
Dynamic Visual Acuity ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
The Absolute ◽  
Poor Relationship

Contrary to standard teaching, many patients with bilateral vestibular loss clearly deny oscillopsia or imbalance in darkness. In an attempt to characterize these patients within the larger population of all patients with bilateral vestibular loss, the rotation and posturography test results of 22 patients with bilateral vestibular loss were reviewed. In addition, dynamic visual acuity was assessed with an eye chart test. There was a poor relationship between oscillopsia and dynamic visual acuity or rotation testing. There were three patterns of response on rotation testing, and loss of high-frequency gain was seen in as many patients who reported oscillopsia as did not. There were some patients with normal gain values at all frequencies tested who reported oscillopsia. It may be that the change in the VOR, rather than the absolute VOR loss, is responsible for the production of oscillopsia. On the basis of this and other studies, treatment strategies for patients with bilateral vestibular loss are suggested.

Effect of vestibular rehabilitation on passive dynamic visual acuity

2008 ◽  
Vol 18 (2-3) ◽  
pp. 147-157
Author(s):  
Matthew Scherer ◽  
Americo A. Migliaccio ◽  
Michael C. Schubert
Keyword(s):  
Visual Acuity ◽  
Exercise Program ◽  
Home Exercise ◽  
Dynamic Visual Acuity ◽  
Gaze Stabilization ◽  
Ocular Reflex ◽  
Gaze Stability ◽  
Before And After ◽  
Vestibulo Ocular Reflex ◽  
Head Impulses

While active dynamic visual acuity (DVA) has been shown to improve with gaze stabilization exercises, we sought to determine whether DVA during {passive} head impulses (pDVA) would also improve following a rehabilitation course of vestibular physical therapy (VPT) in patients with unilateral and bilateral vestibular hypofunction. VPT consisted of gaze and gait stabilization exercises done as a home exercise program. Scleral search coil was used to characterize the angular vestibulo-ocular reflex (aVOR) during pDVA before and after VPT. Mean duration of VPT was 66 ± 24 days, over a total of 5 ± 1.4 outpatient visits. Two of three subjects showed improvements in pDVA with a mean reduction of 43% (LogMAR 0.58 to 0.398 and 0.92 to 0.40). Our data suggest improvements in pDVA may be due in part to improvements in aVOR velocity and acceleration gains or reduced latency of the aVOR. Each subject demonstrated a reduction in the ratio of compensatory saccades to head impulses after VPT. Preliminary data suggest that active gaze stability exercises may contribute to improvements in pDVA in some individuals.

scholarly journals Importance of high-frequency vestibular function in the prognosis of bilateral vestibulopathy

2020 ◽  
Author(s):  
Seonghoon Bae ◽  
Gi Sung Nam ◽  
Sang Hyun Kwak ◽  
Sung Huhn Kim
Keyword(s):  
High Frequency ◽  
Vestibular Function ◽  
Vestibular Rehabilitation ◽  
Composite Score ◽  
Head Impulse Test ◽  
Caloric Test ◽  
Bilateral Vestibulopathy ◽  
Dynamic Posturography ◽  
Vestibulo Ocular Reflex

Objective: To investigate whether preserved vestibular function in the high-frequency range influences the prognosis after vestibular rehabilitation in patients with BVP.Methods: Twenty-four patients followed up with vestibular rehabilitation were recruited. Enrolled patients were divided into two groups according to the preservation of high-frequency vestibulo-ocular reflex (VOR) based on the video head impulse test (vHIT). The results on the computerized dynamic posturography (CDP) and dizziness handicap inventory (DHI) survey collected at baseline and at the 6-month follow-up with vestibular rehabilitation therapy were analysed. Results: Both groups showed significantly increased composite and DHI scores after follow up with vestibular rehabilitation. The high-frequency VOR preserved group showed a better composite score (p = 0.064) and vestibular score (p = 0.008) than the high-frequency VOR loss group at the 6-month follow up. The DHI score was significantly decreased only in the high-frequency VOR loss group (p = 0.047). Among the three vestibular function tests (caloric test, rotary chair test, vHIT) used to diagnose BVP, only vHIT showed a significant correlation (p = 0.015) with favourable prognosis (composite score

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