Quantitative on-line analysis of physiological data for lesion placement in pallidotomy

A computerized method of determining the focal point of electrical activity in the pallidum of parkinsonian patients was developed using on-line quantitative physiological data analysis. Thirty patients in a series of 70 were studied in depth. Neuronal activity was recorded from the pallidum using a semi-microelectrode. The signal is inspected visually while its average power, characteristic frequency and complexity are computed. The target locus was indicated by the highest level of global activity in the vicinity of the electrode (signal power maximum), maximal signal complexity and minimal characteristic frequency. Most often, the vertical coordinate required correction. The postoperative clinical and imaging results have indicated the effectiveness of this method.