Contralesional High-Acceleration Vestibulo-Ocular Reflex Function in Vestibular Schwannoma

Area of Science:

• Neuroscience
• Ophthalmology
• Otolaryngology

Background:

• Vestibular schwannoma (VS) commonly causes ipsilesional vestibulo-ocular reflex (VOR) impairment.
• The mechanisms behind bilateral VOR impairment in VS patients remain unclear.
• Tumor size has been suggested to correlate with VOR gain.

Purpose of the Study:

• To investigate the impact of unilateral VS on ipsilesional and contralesional high-acceleration VOR function.
• To evaluate factors contributing to contralesional VOR impairment in VS patients.
• To assess the relationship between tumor characteristics and VOR function.

Main Methods:

• Retrospective chart review of 101 unilateral VS patients.
• Utilized video head impulse testing (vHIT) for VOR assessment.
• Correlated VOR gain with tumor size and brainstem compression (MRI).

Main Results:

• 80% of patients had ipsilesional VOR impairment; 43% had contralesional VOR impairment.
• Bilateral VOR impairment occurred in 42% of patients and correlated with tumor size.
• Brainstem compression was linked to reduced ipsilesional VOR gain but not contralesional VOR gain.

Conclusions:

• Unilateral VS frequently leads to bilateral VOR impairment, particularly with larger tumors.
• Brainstem compression influences ipsilesional VOR function.
• Further research is needed to fully elucidate the mechanisms of contralesional VOR impairment in VS.