Larger phase angle between sleep propensity and melatonin rhythms in sighted humans with non-24-hour sleep-wake syndrome.
OBJECTIVE
This study was aimed to clarify phase angle between sleep propensity and the circadian pacemaker in patients with non-24-hour sleep-wake syndrome (Non-24).


METHODS
A case-control study was underaken.


METHODS
Sighted patient with Non-24 (4 males and 1 female, aged 16 to 39 y), and sex- and age-matched healthy controls (12 males and 3 females, aged 19 to 35 y) participated the study. MEASUREMENT AND INTERVENTION: Following an actigraphic assessment of the sleep-wake cycle in their homes, the participants entered an ultra-short sleep-wake schedule together with simultaneous measurement of dim light melatonin rhythm after 24-hour sleep deprivation.


RESULTS
The period of the sleep-wake cycle observed at home was longer in the Non-24 patients (25.12 hours) than in the controls (24.02 hours, p<0.0001). The interval from sleep propensity (SP) onset to the melatonin midpoint (MLmid) was significantly shorter in the Non-24 patients than in the controls. The interval from the MLmid to the SP offset was significantly longer in the Non-24 patients than in the controls.


CONCLUSIONS
It was postulated that Non-24 sufferers' delayed SP onset relative to the circadian pacemaker may accelerate the light-induced phase-delay, leading to sleep-wake cycle that is longer than 24 hours.
Uchiyama
Makoto
M
Department of Psychophysiology, National Institute of Mental Health, National Center of Neurology and Psychiatry, Ichikawa, Japan. macoto@ncnp-k.go.jp
Shibui
Kayo
K
Hayakawa
Tatsuro
T
Kamei
Yuichi
Y
Ebisawa
Takashi
T
Tagaya
Hirokuni
H
Okawa
Masako
M
Takahashi
Kiyohisa
K
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002940:Circadian Rhythm / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008550:Melatonin / Q000097:blood / Q000378:metabolism*; D017286:Polysomnography; D020178:Sleep Disorders, Circadian Rhythm / Q000175:diagnosis / Q000453:epidemiology / Q000378:metabolism*
D008550:Melatonin