Department of Neurology

The 1st Hospital.The methods of analysing power spectrum with multichannel and its brain e-lectric activity mapping(BEAM)were investigated firstly by us and were used to evaluate quantitative EEG(qEEG)changes after MCA-o in rats.A off-line computer analysis was carried out to calculate the relative power spectrum(percentage power spectrum). Discrete Fourier Transformation using FFT based on the Bartlett’s averagcd periodograms esijmate was used. Delta focus was found in the ischemic region accompanied by an asymmetrical distribution of the Alpha with power reduction.Some parameters such as percentage of Delta.Alpha and its relative asymme-try ratio(R-L)/(R-L)will be of great value for us in locating the focus of ischemia after experimental cerebral ischemia in rats