Auditory and colored visual P300 in patients with sequelae of subacute myelo-optico-neuropathy.

To study the cognitive function in 13 patients with sequelae of subacute myelo-optico-neuropathy (SMON), event-related potentials (ERPs) were elicited with tones, clicks, and colored visual stimuli in different tasks. P300 latency was delayed, and P300 amplitude reduced or absent in 5 patients (38%), although neuropsychological assessment for dementia did not differ between patients and 21 age-matched normal controls. P300 and N200 latencies with the tone/tone auditory stimuli and N200 latency with the visual stimuli were significantly delayed, but the latencies of early components (N100 and P200) were not delayed. These findings suggest that SMON patients may have cognitive dysfunction to a slight degree.