Definition

1. Noun:
   • A specific type of brain wave: "delta rhythm" refers to the pattern of electrical activity in the brain characterized by high amplitude and very low frequency, typically between 1 to 4 cycles per second (hertz). It is the dominant brainwave observed in an electroencephalogram (EEG) during deep, dreamless sleep.

Usage Examples

• Noun:
  • The presence of delta rhythm on the EEG is a key indicator of stage 3 non-REM sleep.
  • As the patient entered a deeper state of unconsciousness, the monitor showed a clear delta rhythm.

Advanced Usage

• "To exhibit/show a delta rhythm": to display this specific brainwave pattern.
  • The sleeping infant's EEG began to exhibit a strong delta rhythm.

Variants and Related Words

• Delta wave (n): a synonym for delta rhythm, referring to a single cycle of this brainwave pattern.
  • Each large, slow wave on the readout was identified as a delta wave.

Synonyms

• Slow-wave sleep activity: brain activity associated with deep sleep stages.
• Delta activity: a broader term for neural oscillations in the delta frequency range.

Related Terms

• Theta rhythm: a brainwave pattern (4-8 Hz) associated with light sleep or drowsiness.
• Alpha rhythm: a brainwave pattern (8-12 Hz) associated with relaxed wakefulness.
• Beta rhythm: a brainwave pattern (12-30 Hz) associated with active, alert states.

Noun

1. the normal brainwave in the encephalogram of a person in deep dreamless sleep; occurs with high voltage and low frequency (1 to 4 hertz)