Otolith Function Tests in Patients with Unilateral Vestibular Lesions

Abstract

This study was designed to assess the utility of otolith-ocular reflex testing in patients with complete unilateral peripheral vestibular deficits. Ten subjects were given a clinical vestibular test battery (ENG & vertical rotation) and research oriented tests of otolith function including dynamic posturography with head tilt and earth-horizontal axis rotation with otolith-visual interactions. Clinical tests confirmed the presence of a vestibular deficit and the side of the lesion. The results suggested the following: posturography during head tilt is not a reliable means of detecting unilateral peripheral vestibular dysfunction. while earth-horizontal axis rotation is a reliable means of assessing asymmetric otolith function. The Bias response during earth-horimntal axis rotation was significantly less during rotation ipsilateral to the lesioned ear compared to contralateral rotation while the Mod response was normal. The optokinetic test results in these subjects were normal while otolith-visual interactions were symmetrically reduced in these patients.

Key Words:

• unilateral vestihular deficit
• vestihulo-ocular reflex
• visual vestibular interactions
• otolith organs
• dynamic posturography
• optokinetic nystagmus
• electronystagmography
• vertical rotation