Sleep duration at night affects daytime wake EEG spectra

Sleep deprivation leads to decreased performance, alertness and degradation in the health status of a person. Often the person remains unaware of the reduced alertness and may end up taking inaccurate decisions. There was a need to study the sleep duration of college goers and to study the effect of total night-time sleep duration on daytime Electroencephalogram (EEG) characteristics.

A total of 30 asymptomatic volunteers were enrolled in a cross-sectional study. A baseline sleep diary for fourteen days was taken and one daytime recording was done while carrying out their normal daytime activity. EEG, electrooculography (EOG) and electromyography (EMG) were recorded, which were used for the scoring of their sleep-wake using the American Academy of Sleep Medicine criteria. EEG data were analysed using fast Fourier transform. Fast Fourier transform was done for sleep and wake durations using DOMINO software (©SOMNOMEDICS, Germany). A Python library was used to calculate power spectral density (PSD) in EEG frequency bands.

A beta band was significantly reduced in the first 45 min of the recording as compared to the baseline. K means cluster showed clustering of two groups with a significant reduction of daytime sleep delta PSD values with reduced total sleep time and time in bed the previous night. The study concluded that subjects with reduced night-time sleep duration generated significantly lesser sleep delta PSD values.

Reduced duration of night-time sleep was associated with worse nap time sleep delta PSD values and vice versa. Interestingly, good quality sleep at night correlated better with delta PSD values of daytime recording.