Intermediate
Technical
In the Industry Vocabulary Test
theta rhythm
Pronunciation: THEE-ta
EEG activity in the 4-7 Hz range, normally present during drowsiness and light sleep in adults.
Full Definition
Theta rhythm encompasses EEG frequencies between 4-7 Hz, physiologically present during states of drowsiness, light sleep, and deep meditation in healthy adults. In children and adolescents, theta activity is more prominent during wakefulness and decreases with age. Pathological theta may indicate underlying encephalopathy, metabolic disorders, or structural brain lesions when present excessively during full wakefulness in adults.
Usage
Usage note: Greek letter theta (θ) represents this frequency band in neurophysiology.
In Context
- "Excessive theta rhythm during wakefulness suggested possible encephalopathy." — EEG diagnostic report
- "Normal theta rhythm emerged as the patient transitioned to stage 1 sleep." — Sleep study interpretation
Also known as
theta activity
theta waves
Contrasted with
beta rhythm
gamma rhythm
Don't confuse with
delta rhythm
alpha rhythm