[Brain mapping in Parkinson disease treated by cryothalamotomy]

Brain mapping of the cerebral bioelectric activity was done by the BEAM method in 20 patients with Parkinson's disease treated by cryothalamotomy. Conventional egg examinations demonstrating relatively small changes of the type of local asymmetry of frequencies and/or amplitudes, sporadic focal changes, and sporadic generalized and disseminated generalized changes were analysed in a computer system in the domain of frequency and time. Brain mapping demonstrated very distinctly the asymmetry in the frequency bands alpha and beta. On the operated side a regular alpha rhythm of lower frequency but higher amplitude dominated in the brain hemisphere. On the intact side a quick beta rhythm prevailed and an irregular alpha rhythm was noticeable. This phenomenon described by analysis in the domain of frequency confirms the unilateral synchronizing influence of thalamotomy on the bioelectric activity of the operated brain hemisphere and may correlate with the functional motor improvement noted in the operated subjects. In three cases with a longer course of the disease analysis in the frequency domain demonstrated the presence of generalized diffused slow waves in both frontal regions. These changes correlated with mental insufficiency of the examined patients.