Cognitive impairment in epileptic patients and influential factors

Objective To study the executive function impairment and the related factors in patients with epilepsy.Methods A total of 109 adult epileptic patients,who were hospitalized during January 1999 and April 2006 in epilepsy outpatient clinic of our hospital or underwent long-term follow-up,and 75 age-matched healthy controls,were recruited in this study.Both the epilepsy and control subjects were administered with a battery of neuropsychological tests,including the verbal fluency test,Digit Span Test,Digit Symbol Test,Stroop Color-Word Test(word-reading and color-naming speed)and Trail Making Test(Part A).Results The verbal fluency of epileptic patients was significantly worse than that of the control group and their digit span and symbol were both significantly lower than that of the control group;the epileptic patients took significantly more time to accomplish the Trail Making Test and Stroop Color-Word Test than the control group did and their number of errors in the Stroop Color-Word Test was significantly higher(P0.01).Digit span of patients with temporal lobe epilepsy(TLE)was lower than that with frontal lobe epilepsy(FLE).Multiple linear regression analysis indicated higher education and non-TLE were positive for verbal fluency.Higher education,single antiepileptic drug(AED)treatment,short course of the disease and being old were positive for digit span.The short course of the disease,higher education and no intracranial lesions were positive for digit symbol.Conclusion Impairments of multiple executive functions exist in the patients with epilepsy.Patients with higher education also show better executive functions.Patients with TLE show impaired verbal fluency.Digit span is affected by the course of the disease or drugs or age and digit symbol is affected with the course of the disease or existence of lesions.