Differences in electroencephalographic spectra during pre-sleep wakefulness, N1, and R sleep between comorbid insomnia and obstructive sleep apnea

Purpose The neuropsychobiological effects of the comorbidity of insomnia and obstructive sleep apnea are not well studied. Our objective was to compare electroencephalographic spectra of patients with comorbid insomnia and sleep apnea syndrome to those of patients with sleep apnea syndrome alone during pre-sleep wakefulness and the N1 and R sleep periods. Method We performed electroencephalography and polysomnography on 10 patients with comorbid insomnia and sleep apnea and 10 with only sleep apnea. Electroencephalography spectra analysis was performed for absolute power in clinical bands in six derivations. Results Compared to sleep apnea patients, comorbid patients had lower sleep efficiency and total sleep time, higher beta-1 power in the left frontal and central derivations during pre-sleep wakefulness, higher delta power in the left frontal and central derivations during the N1 stage, and higher beta-2 power in the left frontal and central, and right central derivations during the R stage. Conclusions Data suggest that patients with insomnia and sleep apnea, compared to patients with only sleep apnea, presented higher left high-frequency rhythms during pre-sleep wakefulness and R sleep stage, and may be for increased emotional and cognitive-related activity, while in stage N1, presented higher left delta power, which suggest some slowing after sleep deprivation.