Clinical trial NCT04268615: Covert Saccade Triggers in Bilateral Vestibular Hypofunction
Official title: Covert Saccade Triggers in Bilateral Vestibular Hypofunction
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Reflex, Abnormal
Bilateral Vestibulopathy
Healthy Volunteers
Keywords: Saccadic Eye Movements
Bilateral Vestibulopathy
Bilateral Vestibular Hypofunction
Lead sponsor: Hospices Civils de Lyon
Sponsor class: OTHER
First posted: 2020-02-13
Enrollment: 32
Sex: ALL
Minimum age (years): 18
Maximum age (years): 90
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

Brief summary: 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.


Eligibility criteria: Inclusion Criteria:

* 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

1. Postural imbalance
2. Unsteadiness of gait
3. Movement-induced blurred vision or oscillopsia during walking or quick head/body movements
4. 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

Exclusion Criteria:

* Corrected Visual Acuity lower than 5/10
* Other conditions leading to oscillopsia or ataxia
* Oculomotor palsy, ocular instability in primary position
* Treatment that may affect ocular motility (psychotropes)
* Cervical rachis pathology with instability
* Cochlear Implants
* Non-stabilized medical disease
* Pregnant women
* Patients under tutelage
* Patient without social security

Primary outcomes:
measure: Latency of covert-saccades
timeFrame: Day 1
Secondary outcomes:
measure: Frequency of covert-saccades
timeFrame: Day 1
measure: Velocity of covert-saccades
timeFrame: day 1
measure: Amplitude of covert-saccades
timeFrame: Day 1
measure: Latency of visually-guided saccades
timeFrame: Day 1
Other outcomes:
Locations:
city: Bron
country: France
facility: Hospices Civils de Lyon
Study officials:
affiliation: Hospices Civils de Lyon
name: Caroline FROMENT, MD
role: PRINCIPAL_INVESTIGATOR
References: