The role of sleep microstructure in the diagnostic yield ofEEG after sleep deprivation in temporal lobe epilepsy

Objectives: Compared to basal EEG, sleep deprivation (SD) intemporal lobe epilepsy (TLE) increases the occurrence of interictalepileptiform discharges (IEDs). We aimed to evaluate whethermorning sleep after partial nocturnal SD bears additional activatingeffects on IEDs compared with nocturnal sleep, and the potential rolefor sleep instability as measured by cyclic alternating pattern (CAP).Methods: Thirteen TLE patients underwent in-lab nocturnalpolysomnography (n-PSG) and morning SD-EEG, being awake thenight before from 2:00 am and video-EEG taking place at 8:00 am.For both recordings, we obtained, for the first NREM/REM cycles:IEDs/h (Spike Index, SI), sleep macrostructure and microstructure(NREM CAP rate; A1, A2 and A3 Index), and SI association with CAPvariables.Results: The macrostructure of the first sleep cycles was similar in n-PSG and SD-EEG, whereas CAP rate and SI were significantlyhigher in SD-EEG. SI increase was selectively associated with CAPphases.Conclusions: SD increases the instability of morning recovery sleepcompared with n-PSG, particularly enhancing A1 CAP phases, thatare associated with the major occurrence of IEDs. Higher instabilityof post-SD recovery sleep may account for the increased IEDs yieldin SD-EEG in TLE patients