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Purpose: Major depressive disorder (MDD) is associated with cognitive impairment through unclear mechanisms.We examined the relationship between sleep electroencephalogram (EEG) power and attention level in MDD.Patients and Methods: Forty-seven untreated patients with MDD and forty-seven age-and sex-matched controls were included.We examined relative EEG power during non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep by fast Fourier transform.The Attention Network Test (ANT) was performed to evaluate attention levels.Results: Compared to controls, patients with MDD had lower theta power during NREM (P = 0.018) and REM (P = 0.002) sleep, while higher beta power (P = 0.050) during NREM sleep and delta power (P = 0.018) during REM sleep.Regarding attention level, patients with MDD had lower levels of accuracy (P = 0.021), longer mean reaction time (P < 0.001), poorer manifestations of the alerting effect (P = 0.038) and worse executive control (P = 0.048).Moreover, decreased theta power during NREM sleep was correlated with worsened accuracy (β = 0.329, P = 0.040), decreased theta power during REM sleep was correlated with worsened alerting effect (β = 0.355, P = 0.020), and increased delta power during REM sleep was correlated with longer mean reaction time (β = 0.325, P = 0.022) in patients with MDD.No association between ANT performance and other frequency bands was observed in patients with MDD.Conclusion: Our findings suggest that patients with MDD manifest impaired selective attention function that is associated with decreased theta power during NREM/REM sleep and increased delta power during REM sleep.
Cai et al. (Sat,) studied this question.