Covert Saccade Triggers in Bilateral Vestibular Hypofunction

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.

Conditions

• Reflex, Abnormal
• Bilateral Vestibulopathy
• Healthy Volunteers

Interventions

OTHER

Covert Saccades and Virtual Reality

During this intervention, patients will undergo head impulse testing while wearing virtual reality Headsets. During the head impulse tests the visual information will be modified in order to create a conflict between head rotation and rotation of the visual scene. Recording of head and eye movement will be done during these head impulses in order to verify if visual information modifies compensatory eye movements during head impulses.

OTHER

Actives versus passives Head Impulses

Patients will undergo classic passive head rotation as well as active head rotation in order to compare latencies of covert saccades in both conditions.

OTHER

Visually guided saccades

Patients as well as healthy control subjects will undergo testing of visually guided saccades in different conditions (step, gap, overlap) in order to compare latencies of covert saccades between both groups.

Sponsors & Collaborators

• Hospices Civils de Lyon

  lead OTHER

Principal Investigators

• Caroline FROMENT, MD · Hospices Civils de Lyon

Study Design

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

90 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2020-12-15

Primary Completion

2022-03-21

Completion

2022-03-21

Countries

• France

Study Locations