PSD Analysis of Human Different Sleeping Stages EEG Signals in Various Band on MATLAB

In recent decades, researchers have categorized sleep into four distinct stages, primarily characterized by changes in different frequency bands of EEG signals. Studying brain wave signals can provide insights into the mechanism of sleep and the treatment of sleep-related disorders. This paper presents an in-depth analysis of the power spectral density (PSD) of human sleep EEG signals, focusing on the relative power percentages of the Delta, Theta, Alpha, Beta, and Gamma frequency bands. The experimental data were obtained from the study of C.I. Acı and M. Kaya. The subjects were healthy males aged 23 and 26 years old. Using MATLAB, this study analyzed the PSD of EEG signals over various time intervals to observe changes in frequency bands and their relative power percentages. This study found that during the first 10 minutes, both subjects were in the NREM phase, and both of their Delta waves were most pronounced during the first 10 minutes. At 10-20 minutes, subject 1 gradually shifted to REM, with an increase in the high-frequency component of the EEG signal, while subject 2's did not change significantly. At 20-30 minutes, both subjects gradually moved into wakefulness, with the high-frequency component dominating. These findings lay the groundwork for future research on the PSD of EEG signals across different stages of human sleep.