Effect of carbamazepine on the sleep microstructure of temporal lobe epilepsy patients: a cyclic alternating pattern-based study

•Sleep microstructure was assessed in drug naïve and carbamazepine (CBZ) treated patients with temporal lobe epilepsy (TLE).•Assessment of cyclic alternating pattern (CAP) and arousal parameters was carried out.•Patients with TLE showed greater sleep microstructural disturbances compared to healthy controls.•Microstructural disturbances were worse in CBZ treated patients compared to drug naïve during non-rapid eye movement sleep.

BackgroundStudies looking at the effect of anti-epileptic drugs on the sleep microstructure of patients with epilepsy are scarce. The aim of this study was to compare the sleep microstructural characteristics of drug-naive temporal lobe epilepsy (TLE) patients and those on carbamazepine (CBZ) monotherapy.MethodsThree age-matched (p = 0.286) and sex-matched (p = 0.398) groups were studied: drug-naive TLE (n = 20); TLE on CBZ (n = 20); and healthy controls (n = 40). All groups underwent overnight polysomnography. Scoring and analysis of arousals and cyclic alternating pattern (CAP) parameters were performed. Comparison of arousal parameters and CAP parameters was performed using either one-way analysis of variance or the Kruskal−Wallis test, followed by pairwise comparisons (p ≤ 0.05).ResultsRapid eye movement (REM) arousal indices and overall CAP rates were higher in patients with TLE (group 1, p < 0.001; group 2, p < 0.001) compared to controls. Furthermore, the overall CAP rate was higher in patients on CBZ. The CAP cycle/sequences indices (group 1, p < 0.001; group 2, p < 0.001) were higher, and conversely, the average duration of CAP cycles/sequences (group 1, p = 0.018; group 2, p = 0.003) was lower in patients with TLE. Finally, an increase in A2 percentage was noted in patients with TLE (group 1, p = 0.011; group 2, p = 0.011).ConclusionWe found significant alterations in REM arousal indices and CAP parameters in patients with TLE as compared to controls. Moreover, many of these CAP alterations were greater in patients on CBZ. These findings suggest that anti-epileptic drugs such as CBZ may augment arousal instability in patients with TLE, and hence worsen sleep quality and continuity.