Visual and somatosensory evoked potentials in hereditary motor-sensory neuropathies

Visual (VEP) and somatosensory evoked potentials (SEP) were studied in 31 patients with hereditary motor-sensory neuropathy (HMSN)--in the absolute majority of cases HMSN type I. Prolonged P100 latency was found in the two oldest patients only, though the amplitude of that wave was significantly lower in the adult patients compared with the controls. Typical SEP findings were poorly detectable waves N9,N13 and spinal wave with prominently prolonged N20 und P40 latencies. The amplitude of these cortical components again decreased in proportion to the patients' age. Surprisingly, the greatest involvement of the peripheral sensory and motor nervous systems with the most prominent SEP alteration was found in the youngest generation while in the previous generations there was, in contrast, a more conspicuous component of central affection.