A mechanistic appraisal of cognitive dysfunction in epilepsy.

A strong relationship between the clinical characteristics of epilepsy and the nature of cognitive impairments associated with the condition has been found, but the nature of this relationship appears to be quite complex and not well understood. This review presents a summary of the research on the interaction between cognition and epilepsy, surveyed from a mechanistic perspective with the aim of clarifying factors that contribute to the co-existence of both disorders. The physiological basis underpinning cognitive processing is first reviewed. The physiology of epilepsy is reviewed, with emphasis placed on interictal discharges and seizures. The nature of the impact of epilepsy on cognition is described, with transient and prolonged effects distinguished. Finally, the complexity of the co-morbidity between cognitive dysfunction and epilepsy is discussed in relation to childhood and adult-onset epilepsy syndromes and severe epileptic encephalopathies. Structural and functional abnormalities exist in patients with epilepsy that may underpin both the cognitive dysfunction and epilepsy, highlighting the complexity of the association. Research, possibly of a longitudinal nature, is needed to elucidate this multifactorial relationship between cognitive dysfunction and epilepsy.