Evaluation of multiple-frequency rotatory testing in patients with peripheral labyrinthine weakness.

Multiple-frequency rotatory testing was performed in a series of 12 normal subjects and 27 patients who had significant labyrinthine paralysis. Fourteen of the patients had total loss of labyrinthine function. Phase leads of the responses were much greater in the lower-frequency measurements and measured gains of the responses to ampullopetal stimulation were qualitatively greater than those of the responses to ampullofugal stimulation. However, many patients' responses continued to fall within the normal range because of the large variability of the responses of normal subjects. The value of rotatory testing in clinical diagnosis is discussed.