Evoked potentials in hereditary spastic paraplegia.

Pattern reversal visual evoked response (VER) and monaural stimulation of brainstem auditory evoked responses (BAER) were recorded from both sides in 25 patients (males 19; females 6) with hereditary spastic paraplegia (HSP). Their age ranged from 15-52 (mean +/- SD; 25.2 +/- 22.5) years and duration of symptoms 6 months-9 (mean +/- SD; 4.2 +/- 3.6) years. A prolonged P100 latency was seen in 6 patients and BAER abnormality in 13. None of the patients had clinical evidence of brainstem involvement. It is suggested that VER and BAER abnormalities are due to segmental demyelination and fiber loss in central conduction pathways and could serve as an important tool for the diagnosis of this disorder.