Wavelet analysis of evoked potentials

Ischemic neurological injury has been shown to alter the temporal and spectral features of somatosensory evoked potentials. Multiresolution wavelet analysis is employed in this study to quantitate such injury-related changes. EP signals are decomposed into constituent "coarse" and "detail" components. In the frequency domain, these components correspond to the lowpass filtered and bandpass filtered signals, respectively. Somatosensory evoked potentials recorded during acute cerebral hypoxia and during subsequent recovery are analyzed. Changes in the shape of the coarse components are shown to be sensitive indicators of ischemia. Amplitude trends of the coarse and the detail components are also shown to follow the ischemic event and subsequent recovery.