Cognitive disorders are common in patients with epilepsy. Their aetiology is multifactorial, being affected by the type and location of the epileptogenic lesion, epileptic syndrome, type of seizures, age of onset, frequency and severity. Timely diagnosis and treatment can help to reduce their impact on the patient's quality of life.
The most significant cognitive deficits are associated with focal epilepsy, although some, usually mild, neuropsychological disorders can be found in idiopathic generalized epilepsy. The use of antiepileptic drugs (AEDs) can cause additional neuropsychological disorders that are of particular concern in learning-age children and elderly patients with cognitive disorders before the start of treatment. Recent studies have raised the concern that the use of some AEDs during pregnancy may cause cognitive disorders in the child exposed to them in utero. Cognitive disorders can also present as a complication of surgery for refractory epilepsy. Some risk factors for significant memory loss after surgery for temporal lobe epilepsy have been described. They include intervention in the dominant hemisphere, good preoperative function and poor functional reserve in the contralateral hippocampus.
The heterogeneity of different types of epilepsy makes case–control studies difficult; however, thanks to the growing interest in the neuropsychological deficits associated with epilepsy, we now know some factors that could lead to the appearance of these disorders and their prognosis. Special care must be taken to detect cognitive side effects associated with AEDs, which seem to be more common with classic than with new AEDs, and in those patients receiving polytherapy. Neuropsychological assessment should be routinely performed before epilepsy surgery to predict possible postsurgical cognitive deficits.