[Multivariate analysis of beta activity in clinical material].

Beta activity, as described by a number of parameters extracted from the power spectra, was submitted to several multivariate statistical techniques in search of interpretable subgroups. The difficulties of doing this on heterogeneous clinical material, as well as various shortcomings of the usual cluster analytical techniques, are outlined. Where longitudinal data are available, the analysis of beta activity may help in monitoring the effects of the therapy. Generally, the large variability between individuals and many sources of errors related to the processes of data collection and parameter extraction indicate that much work remains to be done before even a rough and clinically relevant typology of beta activity will become available.