P300 event-related potentials in probable dissociative generalized amnesia

1. To investigate whether abnormalities in objective neurophysiologic measu res are observable in patients with probable dissociative generalized amnes ia, the P300 and N100 event-related potentials were evaluated in six such p atients in both acute stage and after recovery from amnesia. Findings were compared with those in 12 age- and gender-matched healthy subjects. 2. While latencies did not differ from those of control subjects, P300 ampl itudes in acute-stage recordings were lower than those in controls. Repeate d recordings in the patients showed a significant increase in P300 amplitud e after recovery from amnesia. 3. Amplitude and latency of N100 did not differ between the patient and con trol groups, nor changed significantly after retrieval of memory. 4. These findings suggest that some unknown biological and/or psychologic m echanisms that cause retrograde autobiographic amnesia may impair cognitive function as reflected in an objective neurophysiologic measure such as the P300.