EEG abnormalities as a biomarker for cognitive comorbidities in pharmacoresistant epilepsy.

Cognitive impairment is a common and often devastating comorbidity of pharmacoresistent epilepsy. The cognitive comorbidity can be both chronic, primarily due to the underlying etiology of the epilepsy, and dynamic or evolving because of recurrent seizures or interictal spikes. There is now considerable evidence that interictal spikes can contribute to cognitive impairment. Interictal spikes in both rodents and humans result in transient impairment of memory retrieval, whereas in immature animals, interictal spikes can result in long-term adverse effects on brain development. Interictal spikes therefore contribute to the cognitive impairment in the pharmacoresistant epilepsies. Effective treatment of pharmacoresistant epilepsy needs to target not only the overt seizures but interictal electroencephalography (EEG) abnormalities as well. Wiley Periodicals, Inc.