Effect of valproate on the sleep microstructure of juvenile myoclonic epilepsy patients - a cross-sectional CAP based study.

Objective: Studies looking at the effect of anti-epileptic medications on sleep microstructure of patients with epilepsy are almost non-existent. The aim of this study was to compare sleep microstructural characteristics of drug-naïve juvenile myoclonic epilepsy (JME) patients with those on valproate (VPA) monotherapy.

Methods: Three age- (p = 0.287) and gender- (p = 0.766) matched groups (N = 20 in each group): (1) drug-naïve JME (mean age: 21.2 ± 4.06 years; M : F = 9:11); (2) JME on VPA (mean age: 21.85 ± 4.28 years; M : F = 11:9); (3) healthy controls (mean age: 23.2 ± 3.82 years; M : F = 9:11) underwent overnight polysomnography. Scoring and analysis of arousals American Sleep Disorders Association (ASDA, 2002), cyclic alternating pattern (CAP) (Terzano et al., 2002) parameters were performed. Comparison of arousal and CAP parameters was performed using one-way ANOVA, followed by pairwise comparisons using Fisher's LSD test (p ≤ 0.05).

Results: Rapid eye movement (REM) arousal indices were higher in JME patients (Group 1 [p = 0.002] and Group 2 [p <0.001]), whereas the overall and NREM arousal indices were comparable between the three groups. CAP rate was higher in JME patients as compared to controls (p <0.001). Duration of phase A and its subtypes (p <0.001) was reduced in drug-naïve patients as compared to VPA group and controls. Finally, percentage of phase A1 (p = 0.003) was decreased and A3 (p = 0.045) was increased in drug-naïve patients as compared to VPA group and controls.

Conclusions: We found significant alterations in REM arousal indices and several CAP parameters in JME patients. However, many of these alterations were not seen in the valproate group. This might indicate that anti-epileptic medications such as valproate may beneficially modulate arousal instability in JME patients, and hence promote sleep quality and continuity.