Objective identification of dizzy patients by vestibulo-ocular and vestibulospinal testing

To evaluate how well two new objective tests of vestibular function might help identify truly dizzy patients.

A prospective study of dizzy patients.

Department of Otolaryngology, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec.

Vestibular function (in 39 dizziness clinic patients and 30 normals) was characterized as follows: 1. While subjects sat on a rotatable chair trying to look at a wall target, vestibulo-ocular function was quantified by accuracy of ocular stabilization during brief chair turns imposed during 1-second periods of darkness. 2. While subjects stood feet together rotating their head and torso together from the knees, vestibulospinal function was quantified by the fastest comfortable torsal-head movement made without exacerbating dizziness.

After plotting ocular stabilization accuracy against fastest comfortable torsal-head velocity, patients and normals tended to separate into two groups. Statistical analysis permitted most dizzy patients (sensitivity: 87%), and most normals (specificity: 83%) to be identified.

Results are promising, since approximately 40% of patients had no abnormal vestibular signs.