Impact of epilepsy duration, seizure control and EEG abnormalities on cognitive impairment in drug-resistant epilepsy patients

Cognitive impairment frequently occurs in epilepsy patients. Patients with drug-resistant epilepsy (DRE) have poor drug responsivity and higher seizure frequency which consequently lead to brain damage and may have implications on cognitive status. In the present study, we assessed a frequency and degree of cognitive impairment in 52 patients with drug-sensitive epilepsy (DSE) and 103 DRE patients at three time points (baseline, after 12 and 18 months). Degree of cognitive decline was assessed with Montreal Cognitive Assessment (MoCA) scale. We examined the possible correlation between demographic and clinical characteristics and cognitive deterioration in epilepsy patients. Patients in the DRE group had significantly lower MoCA score than patients in the DSE group at baseline (28.83 ± 2.05 vs. 29.69 ± 0.61, p = 0.003), after 12 months (27.36 ± 2.40 vs. 29.58 ± 1.22, p = 0.000) and 18 months (26.86 ± 2.73 vs. 29.33 ± 1.47, p = 0.000). Patients with DRF epilepsy had significantly lower MoCA score than patients with DSF epilepsy at three time points (28.71 ± 2.48 vs. 29.86 ± 0.35, p = 0.015; 27.22 ± 2.72 vs. 29.52 ± 1.37, p = 0.000; 26.80 ± 2.99 vs. 29.31 ± 1.56, p = 0.000). After 12 and 18 months of follow-up, patients with DRG epilepsy had significantly lower MoCA score than patients with DSG epilepsy (27.52 ± 2.01 vs. 29.65 ± 1.02, p = 0.000; 26.94 ± 2.43 vs. 29.35 ± 1.40, p = 0.000). Illness duration negatively correlated with cognitive status (p = 0.005); seizure control and EEG findings positively correlated with MoCA score (p = 0.000). Illness duration, seizure control, drug responsivity, and EEG findings are significant predictors of MoCA score (p < 0.05). Clinicians have to pay attention to patients with drug-resistant epilepsy and concepts of aggressive treatment to minimize the adverse effects of epilepsy on cognition.