Restriction to a limited set of EEG-target variables may lead to misinterpretation of pharmaco-EEG results.

The number and types of target variables quantified from the spectrally analyzed EEG used in topographic pharmaco-EEG studies are still being discussed. Drug-induced changes of target variables obtained in the alpha frequency band--four absolute and four relative powers as well as three frequency measures--were utilized to assess the effects of xantinolnicotinate in demented patients using a parallel group design and the effects of buspirone in a double-blind, placebo-controlled crossover design. We conclude that for the proper evaluation of the different drug effects on the alpha activity, all these target variables should be considered. Descriptive p values of multiple comparisons within the framework of descriptive data analyses are important tools in interpreting drug effects.