Visual evoked potentials and brain stem auditory potentials in Friedreich's ataxia--a longitudinal study.

Six patients with Friedreich's ataxia, 4 males and 2 females, their ages ranging from 13 to 33 years, were studied. The early manifestations started between age 7 and 13 with an evolution time between 6 and 20 years. Serial visual and brain stem auditory evoked potential recordings were made. A progressive increase in latency, reduction in amplitude and in latency inter-ocular difference of P100 were observed. The pattern of the reversal checker-board visual evoked potential was preserved. A disorganized BAEP pattern, a well defined potential I, a very small potential V and a delay in the interpeak latency were constant findings. The assumption is made of a progressive involvement of both visual and central auditory pathways. Pathophysiological mechanisms are discussed.