Mismatch negativity and N100 in comatose patients.

Mismatch negativity (MMN) and N100 auditory evoked potential were recorded in 52 healthy subjects and in 128 severely comatose patients. The MMN was present in 33/128 patients and N100 in 84/128. A ratio of 30/33 patients with MMN and 70/84 with N100 regained consciousness in a mean time of 6.3 +/- 4 days after the recording session. Thus, in terms of predicting return to consciousness, the MMN was more specific (90.9%) than the N100 (57.6%), but its sensitivity was lower (31.6% for MMN and 73.7% for N100, respectively). The amplitudes of MMN and N100 in comatose patients were smaller than those of healthy subjects. It is concluded that MMN and N100 can be very useful in predicting whether or not a comatose patient will regain consciousness. Copyright 2000 S. Karger AG, Basel