Which EEG wave should not be seen in a normal awake adult?

In a normal awake adult, the presence of delta waves is not expected. Delta waves have a frequency range of 0.5 to 4 Hz and are typically associated with deep sleep stages, particularly during slow-wave sleep. They indicate a state of decreased consciousness and a high level of synchronization across the brain, which does not occur in a fully alert and awake individual.

In contrast, theta waves (4 to 8 Hz), alpha waves (8 to 12 Hz), and beta waves (12 to 30 Hz) can all be present in awake adults under various conditions. Theta waves may appear during drowsiness or relaxation, alpha waves are commonly seen during quiet, resting states with closed eyes, and beta waves are indicative of alertness, active thinking, and concentration. Therefore, the presence of delta waves in a normal awake adult would suggest either a pathological condition or atypical brain activity, as they are primarily associated with sleep states rather than wakefulness.