Sleep disorders affect an individual's ability to sleep well on a regular and natural basis. Inadequate sleep can have adverse outcomes for health and safety. Electroencephalogram (EEG) has been presented as an authentic indicator to monitor brain activities. In this review paper, different procedures of EEG tests for recording and monitoring brain activity during sleep such as the EEG electrodes system and the Dreem headband (DH) have been introduced. Also, the processes of recording and analyzing the data have been discussed and compared with each other. The results of various stages of sleep from EEG tests help sleep specialists diagnose or evaluate sleep disorders accurately and choose appropriate strategies. Sleep disorder management is integral to provide patients with a safe sleeping environment.