Long-latency somatosensory evoked potentials.

Theoretically, long-latency somatosensory evoked potentials (SEPs) provide information on the function of somatosensory associative cortical structures. Their potential role in clinical studies and research has been hampered by the lack of standardized methodology in the use of these SEPs. Other factors, such as drugs, simultaneous stimuli, and state of consciousness, also have far-reaching influences on the various parameters of long-latency SEPs. The knowledge of the origin of most SEP components is at best fragmentary; studies on clinical-electrophysiological correlations seem to be hopeful in this respect. As yet, clinical applications of long-latency SEPs are limited; for future research, studies of disturbances of SEPs are most promising, mainly with regard to diseases of the gray matter, the influence of drugs on the cerebral function, and psychopathology.