Dynamic Visual Acuity Results in Otolith Electrical Stimulation in Bilateral Vestibular Dysfunction.

Area of Science:

• Neuroscience
• Ophthalmology
• Biomedical Engineering

Background:

• Bilateral vestibular disease (BVD) causes oscillopsia, impairing visual acuity (VA) primarily due to VOR deficits.
• Dynamic visual acuity (DVA) testing on a treadmill activates both rotational and translational VOR components.
• Current treatments for BVD and associated visual disturbances are limited.

Purpose of the Study:

• To evaluate the impact of chronic electrical stimulation of the otolith organ on DVA in BVD patients.
• To compare VA with and without a novel vestibular implant during static and dynamic walking conditions.

Main Methods:

• Five BVD patients implanted with a vestibular prototype underwent DVA testing (DIE test) on a treadmill at 0, 2, and 4 km/h.
• Oscillopsia Severity Questionnaire (OSQ) and video head impulse tests (vHIT) were administered pre- and post-implant activation.
• DVA scores were recorded as LogMAR values.

Main Results:

• Significant improvements in OSQ scores and DVA were observed, particularly in dynamic conditions.
• Vestibular implant use facilitated organized corrective saccades during vHIT, without altering gain.
• No significant changes in vHIT gain were noted.

Conclusions:

• Otolithic stimulation via a vestibular implant shows promise in restoring DVA in BVD patients.
• This technology represents a potential therapeutic alternative for managing oscillopsia.
• Further research is needed to elucidate the neurophysiological mechanisms and contributing factors.