Abstracts

Rationale: We recently demonstrated significant differences in self-reported as well as polysomnographically confirmed sleep quality parameters among patients with refractory versus controlled epilepsy. Some reports suggest high cyclic alternating pattern (CAP) rates among patients who have seizures during sleep. Objective: To evaluate NREM sleep stability (CAP parameters) among patients with refractory epilepsy versus controlled epilepsy. Methods: Single night polysomnography (PSG) recordings scored according to AASM guidelines, for consecutive prospectively enrolled patients with medically refractory epilepsy (group-1) versus those with controlled epilepsy (group-2), were analyzed for various CAP parameters. Results: PSG recordings of 20 patients in Group-1 (mean age 19.3+6.7] and of 15 patients in Group-2(mean age 21.2+ 7), were analyzed in this study. The mean duration of epilepsy was 12.4+8 years in group-1 and 5.4 +7.7 years in group-2. Seizure frequency and number of patients on >2 AEDs were significantly different between the 2 groups. Significant differences were observed between the two groups in sleep efficiency (means 77+15] & 95+3), WASO (mean 21.8+13.6] & 5.4+3.5) and arousal indices (mean 12.9 +8 & 5.5+3.7) (p<0.05). However, on CAP analysis, no significant difference was found between the 2 groups in terms of mean CAP time (121.8 + 82 & 116.2 +118 min), CAP rate (29.2 +16.5 & 33.2 +41.3) and number of CAP cycles (298+199 & 278 + 188) respectively. No differences were also observed in terms of rates and indices of different phases (A&B) and phase subtypes (A1, A2, A3) between the 2 groups. (Table 1) Conclusions: Despite significant differences in number of awakenings and arousals between the two groups, CAP rates and other CAP parameters were found to be similar among patients with refractory versus controlled epilepsy. The non-occurrence of seizures during any of the PSG recordings as well as the blunting effect of anti-epileptic drugs may be responsible for this similarity in NREM stability.