Partial sleep deprivation in patients with focal epilepsy: effect on sleep macrostructure and cyclic alternating pattern

Objectives: The potential mechanisms underlining the promoting role of sleep deprivation (SD) for epileptic seizures and interictal epileptiform abnormalities have been extensively studied, but some issues have not been completely addressed. Epileptic phenomena are deeply sensitive to fluctuations of arousal and sleep instability, that may be related to SD. Aim of our study was to evaluate the role of cyclic alternating pattern (CAP) as a potential mechanism through which SD may exert its activating effect. Methods: Eight patients with focal epilepsy (mean age 39  19 yy; 5F, 4M) underwent in-lab polysomnography (PSG) and sleep deprived diurnal PSG after partial SD, being awake from 2 AM, performed within 7 days. Sleep macrostructural and microstructural parameters were evaluated according to standard guidelines. Results: One subject had an epileptic attack recorded during the diurnal polysomnogram and was excluded from the analysis. Macrostructural analysis showed a decreased first REM latency for diurnal sleep (night vs. diurnal sleep: 207.0 + 158.3 vs. 59.2 + 42.4 min), although with a decreased REM percentage (18.0 + 7.8 vs. 10.6 + 10.3) and a trend in increased SWS. Microstructural analysis suggests a greater sleep instability for diurnal sleep, with significantly increased CAP rate (53.5 + 8.2 vs. 66.0 + 9.9), particularly for N2 (44.2 + 9.7 vs. 57.6 + 15.3) and CAP slow components, as reported by increased A1 index (46.0 + 10.0 vs. 57.7 + 17.7). Conclusions: In diurnal sleep after partial SD of subjects with focal epilepsy, CAP and its slow components, are increased and may thus offer a favorable framework through which SD modulates interictal and ictal epileptic activity