After REM debt is accumulated enough, it's common to have SOREM in the beginning of naps or cores, especially close to the REM peak during the dawn hours, which is done by brain to alleviate REM pressure. SOREM is also common for hypersomniac and narcoleptic patients, who generally have excessive REM requirements.
- "Sleep-onset REM Period". Encyclopedia of Neuroscience. 2009. doi:10.1007/978-3-540-29678-2_5445.
- Mosko SS, Shampain DS, Sassin JF (1984). "Nocturnal REM Latency and Sleep Disturbance in Narcolepsy". Sleep. 7 (2): 115–125.