Abstracts

Rationale: Neuropsychological studies in patients with juvenile myoclonic epilepsy (JME) demonstrate cognitive deficits, mainly in functions related to the frontal lobes, with low scores in tests requiring concept formation, mental flexibility, focal attention and inhibitory response control. This study aimed to: 1) evaluate executive functions in patients with JME using a comprehensive battery of neuropsychological tests and; 2) investigate the correlation of different clinical variables with the cognitive performance of patients with JME. Methods: Methods: 26 patients (25 years ±7.3; IQ 86±7.8) with a diagnosis of JME were evaluated by applying a neuropsychological battery of tests made up by: Digit Span, Stroop Color Test (SCT), Trail Making Test (TMT), Wisconsin Card Sorting Test (WCST), Verbal Fluency (FAS), Matrix Reasoning (MR), and Vocabulary subtests from WASI. Results were compared to normative data and were correlated with the following clinical variables: age of onset, disease duration, daily dosage of sodium valproate (VPA), seizure control status, frequency of myoclonic seizures, frequency of generalized tonic-clonic seizures, presence of absence seizures, family history of epilepsy, family history of psychiatric disorders, and personal history of psychiatric disorders. The statistical method used for correlation of clinical variables and test results was Student's "t" test. Results: 24 patients (92.3%) had executive dysfunction (ED), considering that 16 (61.5%) failed in > 5 subtests (severe ED). Twenty-four patients (92.3%) presented low performances in FAS; 88.5% (n=23) in completion time for SCT and Digit Forward; 80.7% (n=21) in Digit Back-forward; 69.2% (n=18) in TMT-A, total mistakes in SCT, and failure to maintain set in WCST. 69.2% had a normal performance in WCST (categories achieved and perseverative errors). As to clinical variables, patients with longer duration of epilepsy had lower performance in FAS and in completion time of SCT; patients with refractoriness (high daily doses of VPA) had low results in MR and FAS; patients with family history for psychiatric disorders had low scores in MR and TMT-A; patients with poor seizure control had lower performance in FAS; and patients with earlier epilepsy onset showed low scores in MR. Conclusions: This study showed executive dysfunction in JME in several domains - attentional span, working memory, inhibitory control, maintenance of goals, and verbal fluency - corroborating our hypothesis of global executive dysfunction in patients with JME, and emphasizing the need for a multidimensional approach when studying the functions of such a complex brain structure as the frontal lobe. However, we observe that distinct clinical variables in JME were associated with worse performance in tests that measure attentional processes, from the most basic to more complex, but not with other frontal lobe functions, such as mental flexibility and planning. This underscores the hypothesis that other mechanisms - structural and functional - are probably implicated in this extensive executive dysfunction.