Cortical excitability in night workers with insomnia is attenuated following a night shift: an ERP study.
Gumenyuk-V; Howard-R; Roth-T; Roehrs-T; Drake-C
Sleep 2013 Jun; 36(Abstract Suppl):A194
Introduction: We previously demonstrated that insomnia in SWD (SWD-INS) is associated with cortical neuronal excitability in the central auditory system, as reflected by enhanced amplitude of the N1 ERP brain response. In this study, we tested whether cortical excitability can be attenuated by 12h of nocturnal sleep deprivation (SD) in SWD-INS. Secondarily, we compared cognitive auditory processing as measured by MMN ERP component in SWD-INS relative to asymptomatic night-workers (ANW) at 18:00 and 06:00, (i.e. beginning and end of the night shift). Methods: 5 night workers with SWD-INS (38yrs+/-10.3yrs, 1 male: ESS 7.8+/-1.2; ISI 15.5+/-3.9) and 9 ANWs (31.5+/-5.5yrs, 3 males: ESS 7.9+/-1.7; ISI 6.6+/-2.8) participated in a baseline (BL) ERP session starting at 18:00 and a SD ERP session starting at 06:00 hours (SD). Between sessions, participants were kept awake in a dimly lit room (10 lux). The N1 brain response to frequency-deviant sounds was measured at a latency of 90-110 ms. The MMN (at a latency of 130-160 ms) was elicited when the brain pre-attentively detected a frequency change in the sound-sequence. Subjects were instructed to ignore all sounds. The peak amplitude of N1 and MMN at BL was compared to that during SD in each group. Results: Sleep deprivation significantly reduced N1 amplitude over the frontal-central electrode (Fz-Cz) in SWD-INS from BL (-1.6+/-0.7 microV) to SD (-0.7+/-0.6 microV, p<0.04). The attenuation of the MMN amplitude after SD was significant in SWD-INS (-0.5+/-0.6 microV) relative to that in BL (-1.0+/-0.8 microV, p<0.03). In ANW, the amplitude of N1 was not significantly different between BL (-1.1+/-0.6 microV) and SD (-1.0+/-0. 7 microV) across Fz/Cz electrodes. The amplitude of the MMN component was similar between BL (-1.0 microV+/-0.7 microV) and SD (-0.7 microV+/-0.9 microV) in ANW. Conclusion: Cortical excitability in SWD-INS is reduced with sleep deprivation during the night shift. Sensory processing in night workers with insomnia is impacted by sleep deprivation during the night shift.
Sleep-deprivation; Sleep-disorders; Shift-work; Shift-workers; Brain-electrical-activity; Brain-function; Brain-matter; Auditory-system; Work-intervals; Humans; Men; Age-groups; Physiological-response; Sound; Sensory-perceptual-processes; Nervous-system
V. Gumenyuk, Sleep Disorders and Research Center, Henry Ford Hospital, Detroit, MI, USA
Henry Ford Health System, Detroit, Michigan