[Spontaneous and evoked electroencephalograms in experimental incomplete cerebral ischemia]

In the present study changes in spontaneous EEG and somatosensory evoked potentials (SEP) under incomplete cerebral ischaemia and in the following reperfusion phase were examined in 8 goats. The neurophysiological parameters were compared with global cerebral blood flow (CBF). At CBF values below 37 ml/100 g/min significant reduction in the EEG power density occurred with a shift of the dominant frequency to lower frequencies. The cortical SEP amplitudes increased significantly with simultaneous increases in latencies. In contrast subcortical components were not affected. In the reperfusion period no complete remission of EEG and SEP changes occurred despite occasional CBF values above the baseline values. The study demonstrates that neurophysiological monitoring can show early functional changes in cases of incomplete cerebral ischaemia.