One of the consequences of epilepsy is impairment of cognitive function and memory impairments, mental slowing and attentional deficits are the most frequent disorders (Aldenkamp et al., 1995a; Dodson and Trimble, 1994). Sometimes such cognitive consequences are more debilitating for the individual patients than the seizures.
The exact causes of cognitive impairment in epilepsy have not been explored fully, but clearly three factors are involved: aetiology, the seizures and the ‘central’ side effects of treatment (Dodson and Pellock, 1993). Aetiology-related factors are often clear, are separate from epilepsy or concern a small group; especially in the age-dependent encephalopathies, such as the West syndrome (Berg and Shinnar, 1997).
We concentrate here on the cognitive effects of seizures and antiepileptic drug treatment. When evaluating these factors it is imperative to realize that in practice most cognitive problems have a multifactorial origin and the three aforementioned factors combined are responsible for most of the ‘make-up’ of a cognitive problem in an individual patient. Moreover the factors are related, which causes therapeutic dilemmas when seizure control can only be achieved with treatments that are associated with cognitive side effects. Nonetheless, these factors are discussed here separately and sequentially. In the last paragraph the overall impact of the factors combined is discussed.
Cognitive side effects of antiepileptic drugs
Treatment of seizures requires antiepileptic drug (AED) treatment for the large majority of patients and may be accompanied by unwanted effects on cognitive function.