Covert Saccade Triggers in Bilateral Vestibular Hypofunction

Status: Completed
Location: See location...
Intervention Type: Other
Study Type: Interventional
Study Phase: Not Applicable

Patients with chronic bilateral vestibular hypofunction may suffer from a visual instability during head movement called oscillopsia. Visual consequence of vestibular deficit can lead to a severe impairment of their quality of life. However, correcting saccades during rapid head movement, called covert-saccades, have been more recently identified. These saccades, which occur during the head movement in patients with vestibular hypofunction, present a very short latency. They could compensate for the lack of vestibular-ocular reflex and greatly decrease oscillopsia and visual impairment. The triggering of these covert-saccade is still not known. They could be of visual origin but the short latency is unusual. The objective of this study is to evaluate the potential role of visual trigger in 12 patients with chronic bilateral areflexia, using different visuo-vestibular conditions. The latency of simple visually guided saccades will also be tested in the group of patients and a group of 12 healthy controls.

Participation Requirements
Sex: All
Minimum Age: 18
Maximum Age: 90
Healthy Volunteers: Accepts Healthy Volunteers

⁃ For all :

⁃ Age from 18 to 90

⁃ Understanding of the experimental instructions

⁃ Informed Consent

⁃ For Patients :

⁃ Bilateral vestibular hypofunction with regards to the criteria of the of the Barany Society A. Chronic vestibular syndrome with at least three of the following symptoms

⁃ Postural imbalance

⁃ Unsteadiness of gait

⁃ Movement-induced blurred vision or oscillopsia during walking or quick head/body movements

⁃ Worsening of postural imbalance or unsteadiness of gait in darkness and/or on uneven ground B. No symptoms while sitting or lying down under static conditions C. Bilaterally reduced or absent angular VOR function documented by

⁃ bilaterally pathological horizontal angular VOR gain < 0.6, measured by the video-HIT5or scleral-coil technique and/or

⁃ reduced caloric response (sum of bithermal max. peak SPV on each side < 6°/sec7)and/or

⁃ reduced horizontal angular VOR gain < 0.1 upon sinusoidal stimulation on a rotatorychair (0.1 Hz, Vmax = 50°/sec).

⁃ D. Not better accounted for by another disease

• For Healthy control No ENT or neurological disorders

Other Locations
Hospices Civils de Lyon
Time Frame
Start Date: December 15, 2020
Completion Date: March 21, 2022
Target number of participants: 32
Experimental: Patients
Patients suffering from chronic bilateral vestibular hypofunction
Active Comparator: healthy subject group
Ruben HERMANN, Caroline FROMENT, Caroline TILIKETE
Leads: Hospices Civils de Lyon

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