Psychometric and neurophysiological assessment of cognitive functions in patients with epilepsy

BACKGROUND: The aim of the study was to assess cognitive functions in patients with epilepsy using the neurophysiological method and psychological tests, and analysis the relationship between clinical features of the disease and test results. MATERIAL AND METHODS: The study included 31 patients with epilepsy aged 37.3±18.4 years. The control group consisted of 40 healthy volunteers aged 33.5±12.2 years. Cognitive functions were assessed using endogenous evoked potential P300 and psychological tests - Mini-Mental State Examination (MMSE), three subtests of Wechsler Adult Intelligence Scale-Revised (WAIS-R), Trail Making Test (TMT), Benton Visual Retention Test (BVRT) and State-Trait Anxiety Inventory (STAI). RESULTS: Epileptic patients achieved significantly lower scores in all, except STAI-1, psychological tests in relation to the controls. A correlation between age and TMT-A (p<0.050) and BVRT (p<0.050) was observed. The disease duration affected results of MMSE (p<0.050), TMT-B (p<0.050) and BVRT (p<0.050). Type of seizures was related to results of MMSE (p=0.005), type of therapy - to results of STAI-1 (p=0.014) and TMT-B (p=0.008). The average latency of P300 was significantly prolonged (p=0.00003) in epileptic patients (348±38ms) in relation to the controls (324±26ms). The relationship between P300 and the duration of seizures (p=0.017) was observed. There was no correlation between P300 and age, sex, frequency and type of seizures and therapy. A correlation between P300 and TMT-B (p<0.050), BVRT-LPO(p<0.050) and STAI-1 (p<0.050) was noticed. CONCLUSION: In epileptic patients cognitive impairment is often found. It is advisable to perform regular neuropsychological testing; P300 can be used only as a preliminary assessment.