Which type of brain wave would likely be seen during deep sleep on an EEG?

Delta waves are characterized by their high amplitude and low frequency, typically ranging from 0.5 to 4 Hz. These brain waves are most prominently observed during deep sleep, specifically in the slow-wave sleep stage (NREM sleep stage 3). During this deep sleep phase, the body undergoes various restorative processes, including tissue growth and repair, immune function enhancement, and energy restoration, which are essential for physical and mental health.

While beta waves are associated with alertness and active thinking, alpha waves signify a relaxed yet awake state, such as during meditation or drowsiness. Theta waves are present during lighter stages of sleep and can also occur during deep relaxation or creativity. However, it is the presence of delta waves that distinctly indicates the brain’s activity during the profound restful state of deep sleep, making them the correct choice for this question.