CLINICAL-PATHOLOGICAL CORRELATION IN A PATIENT WITH SELECTIVE LOSS OFHAIR-CELLS IN THE VESTIBULAR ENDORGANS

We found a selective loss of vestibular hair cells in a patient follow ed for more than 10 years with imbalance and oscillopsia due to idiopa thic progressive loss of vestibular function. Hearing function and coc hlear hair cells were normal. The vestibule-ocular reflex (VOR) gain a t high frequencies was relatively maintained despite marked shortening of the dominant VOR time constant (to less than 500 ms). Ultrastructu ral examination of remaining hair cells showed mitochondrial abnormali ties. The ultrashort VOR time constant probably resulted from changes in firing patterns of the primary afferent nerves due to loss of hair cells and impaired energy metabolism in remaining hair cells.