"Equiphasic" Natural Recordings by Native Speakers
Equiphasic refers to a pattern of brain wave activity during sleep where both delta waves (slow, high-amplitude waves associated with deep sleep) and REM (rapid eye movement) waves (fast, low-amplitude waves associated with dreaming) are present simultaneously, typically in a 50:50 ratio. This stage of sleep is also known as paradoxical sleep, as it combines the slow, peaceful activity of delta waves with the rapid, dream-like activity of REM sleep.