Contralateral Hyperactive Caloric Response in Unilateral Labyrinthine Weakness

Abstract

In a series of 600 patients, 10 showed unilateral hyperactive caloric responses without a trivial explanation such as spontaneous nystagmus or directional preponderance. All 10 had unilateral weakness on the contralateral side, which was accompanied in 9 by cochlear hearing loss. It is assumed that the phenomenon of unilateral hyperreactivity in these cases can be explained by release from commissural inhibition on the basis of temporary vestibular decompensation.

Key Words:

• velocity step test
• directional preponderance
• Meniere's disease
• vestibular decompensation