Long-lasting deviation of the subjective visual horizontal after complete unilateral vestibular deafferentation by subtotal resection of the temporal bone

This study examined whether subjective visual horizontal (SVH) could be compensated in patients with complete loss of unilateral vestibular function. Patients comprised two men and three women who underwent subtotal resection of the unilateral temporal bone due to squamous cell carcinoma of the middle or external ear. Mean patient age was 63.2 years (range, 59-69 yr). Diagnostic. Patients were tested postoperatively (mean, 4 yr 5 mo after the surgery; range, 2 yr 9 mo to 8 yr 6 mo). The task for patients involved adjusting a laser projection bar four times to SVH in darkness. All patients displayed marked deviation of SVH toward the operated side-down. Mean deviation from four trials for each subject was 4.5, 2.9, 3.7, 3.0, and 3.4 degrees. Deviation of SVH in patients with definite unilateral vestibular deafferentation can be long term, lasting more than 2 years at least.