Abnormal somatosensory evoked potentials in amyotrophic lateral sclerosis.

A patient with typical clinical and electromyographic features of amyotrophic lateral sclerosis (ALS) was found to have abnormal somatosensory evoked potentials (SEPs). Evoked responses are generally considered to be normal in ALS despite occasional pathological and clinical evidence of sensory involvement. Thus, abnormal SEPs are considered to argue against a diagnosis of ALS. Based on the present case and a review of the literature, we suggest that abnormal SEPs need not exclude a diagnosis of ALS.