What frequency range is considered typical for alpha waves in an adult?

Alpha waves are a prominent feature in the electroencephalogram (EEG) recordings of adults, especially during states of relaxation while the eyes are closed. The typical frequency range for alpha waves is between 8 and 12 Hz. This frequency range corresponds to a calm, alert state often associated with relaxation, meditation, or reduced sensory input.

Alpha waves are primarily generated in the occipital lobe when a person is awake but in a restful state, and their presence indicates that the brain is in a state of readiness to process information without actively concentrating on tasks. Thus, understanding that this specific range of 8 to 12 Hz characterizes alpha brain activity is crucial for interpreting EEG data in both clinical and research settings.