|delta rhythm or delta wave|
|physiol See also brain wave the normal electrical activity of the cerebral cortex during deep sleep, occurring at a frequency of 1 to 4 hertz and detectable with an electroencephalograph|
|delta wave or delta wave|
delta rhythm n.
A brain wave pattern originating from the forward portion of the brain and having a frequency of between 1.5 and 4.0 hertz; it is associated with deep sleep in normal adults. Also called delta wave.