VALUE OF P300 AS A SCREENING TOOL OF COGNITIVE IMPAIRMENT IN EPILEPSY: A PROSPECTIVE STUDY FROM INDIA

Objective. Preservation of cognition is essential for good quality life. Epileptic pathological processes and pharmacotherapy are thought to be responsible for the cognitive dysfunction (CDF) in persons with epilepsy (PWE). Regular monitoring of persons on antiepileptic drugs (AED) for CDF is recommended. P300, an attention dependent event related potential (ERP), is known to be abnormal in PWE. The value of P300 in monitoring cognitive functions has not been tested prospectively. Material and methods. PWE not exposed to AED in preceding 6 months were recruited and prescribed one of the three common AEDs i.e. carbamazepine, phenytoin and valproate. Subjective tests of cognition-MoCA, Trail making test, Paragraph memory tests, Stroop test in addition to P300 ERP were administered before initiating AED and repeated after three months on the prescribed AED. The significance of the change in the scores of cognitive tools and P300 latency was ascertained by paired t-test. Outcome. Thirty eight PWE (females 18, mean age mean = 22.89±9.39 yr) qualified the inclusion criterion. The values of P300 latency and deployed subjective tests of cognition at two data collection points were compared with the clinical profile of the patients. Performance of the patients deteriorated on all the cognitive batteries after exposure to AED (mean 107.84±19.2 days). The deterioration was independent of education level, type of AED and seizures. Prolongation of P300 latency from baseline was seen in 30 of 38 patients (78.94%). The sensitivity of P300 for picking cognitive dysfunction was 80.64% taking MoCA scores as a reference. Conclusions. Attention along with several other domains of cognition is affected adversely with AED exposure. The P300 could be useful for monitoring cognitive adverse effects of AED in PWE.