Consciousness as a neurological concept in epileptology: a critical review.

This essay explores the usefulness of the concept of consciousness in epileptology and concludes that it does not further the understanding of seizure mechanisms and brain function. The reasons for this are both theoretical and empirical. Consciousness cannot be adequately defined. This may explain why attempts at accounting for it in neurobiological terms have failed. Epistemological and scientific arguments are reviewed which suggest why a satisfactory explanation of consciousness is not now and may never be possible. There are, however, aspects of conscious experience such as perception, cognition, memory, affect, and voluntary motility that are open to neurobiological research. Careful observations of epileptic seizures with "loss of consciousness" often reveal that only some components of consciousness are impaired. "Loss of consciousness" during a seizure, often presenting as unresponsiveness, may be due to aphasia, inability to perform voluntary movements, ictal or postictal amnesia (sometimes with preservation of memory during the ictus itself), or to diversion of attention by a hallucinated experience. A plea is made to observe accurately and interact with the patient during an attack in order to distinguish between these various behavioral disturbances masquerading as "loss of consciousness."