Variations in cognitive functioning in genetic generalized epilepsy: four case studies

Abstract

Summary Introduction The traditional view of cognition in idiopathic or genetic generalized epilepsy (GGE) is that “one size fits all” i.e. only very mild generalized impairment might be detected, if any. This paper describes four case studies of cognitive functioning in GGE patients with photosensitivity and reflexive seizures. Aim The aim was to discover whether each individual’s set of cognitive deficits varied in accordance with his/her other clinical phenomena such as photosensitivity and kinds of reflexive seizures. Method Neurological and cognitive performance was assessed by comprehensive evaluation of each patient based on interviews, neurologist’s EEG reports and neuropsychological tests. Assessment of cognitive domains included estimated pre-morbid I.Q. based on reading ability and demographic norms, current I.Q., attention factors, verbal memory, visual memory and executive functions. Results Clinical signs and investigative studies indicated that two cases typically began reflexive seizure episodes with facial myoclonia which evolved into tonic-clonic convulsions or generalized myoclonic seizures. These patients had widespread attention and working memory deficits, some severe, together with lowered intelligence scores. In contrast, two other cases (with no history of myoclonus) had generalized reflexive seizures originating in the occipital lobes, very mild localized visual dysfunction and high intelligence. Conclusions The systematic variation in extent and nature of cognitive dysfunction illustrated in these cases with reflexive seizures (preceded by myoclonia or visual phenomena) would be explained by a more recent conceptualization of GGE as encompassing regional differences in variable hyperexcitability located at cortical levels or functional neural networks.