Electrophysiological assessment of neuropsychiatric disorders.

In this article the clinical usefulness and limitations of the routine electroencephalogram (EEG) are discussed. Emphasis is placed on 3 specific clinical situations where EEG can be most useful: the differential diagnosis of dementia versus pseudodementia, the evaluation of episodic behavior disorders including aggressive episodes, and acute confusional states. An atypical clinical presentation is emphasized as the most important indiction for obtaining an EEG evaluation. The issue of controversial EEG waveforms is discussed in some detail. The need for well-designed, controlled studies to further examine these EEG patterns is emphasized. Finally, the limitations of the routine EEG are discussed. The article concludes with a brief mention of the future promise of other electrophysiological testing modalities such as quantified EEG, evoked potentials, and sleep studies.