Component P300 of acoustic evoked potential in patients with local brain lesion

The aim of the study was a comparative analysis of spatial-temporary organization of P300 acoustic evoked potential (AEP) in patients with local lesions of the brain stem, frontal and temporal structures in the situations of "passive" listening to sounds and their active recognition (a count). Specific changes of P300 AEP parameters were distinguished in each group. The peak-temporary P300 parameters - latency increase, decrease of amplitude and tendency to the decrease of half-cycle - were similarly changed, irrespective of brain damage topography. A degree of the changes correlated with a level of functional acoustic evoked potential decompensation. In relation to pathologic process location, the topographical P300 AEP features were more specified, comparing to peak-temporary parameters. An existence of two systems for P300 generation at "active" counting and "passive" listening was suggested. In "passive" listening, a response is mostly determined by intact left frontal lobe and middle-stem structures but in "active" counting - by intact right frontal lobe or lobes and limbic system structures (hippocampus).