What does the presence of theta waves in an adult EEG typically indicate?

Theta waves, which typically appear in the frequency range of 4 to 8 Hz, are more commonly associated with states of relaxation, drowsiness, and are often seen during light sleep. In adults, their presence in an EEG can sometimes suggest a transition from wakefulness to sleep or indicate a state of drowsiness. However, when theta waves are observed outside of typical sleep stages in an adult, they may also point towards potential pathological conditions, such as cognitive impairment or other neurological issues.

Notably, while theta waves are a normal part of an EEG in children and during specific tasks, their presence in adults is less frequent and can serve as a marker for domains of concern or a shift from a fully alert state. Thus, the correct response highlights that theta waves in adults can indicate drowsiness or underlying conditions that might warrant further investigation.