TY - JOUR
T1 - Non-24-hour sleep-wake syndrome in a sighted man
T2 - Circadian rhythm studies and efficacy of melatonin treatment
AU - McArthur, Angela J.
AU - Lewy, Alfred J.
AU - Sack, Robert L.
PY - 1996
Y1 - 1996
N2 - The case of a 41-year-old sighted man with non-24 hour sleep wake syndrome is presented. A 7-week baseline assessment confirmed thai the patient expressed endogenous melatonin and sleep-wake rhythms with a period of 25.1 hours. We sought to investigate the underlying pathology and to entrain the patient to a normal sleep-wake schedule. No deficiency in melatonin synthesis was found. Furthermore, normal coupling between the melatonin and sleep propensity rhythms was documented using an 'ultrashort' sleep-wake protocol. Environmental light exposure was monitored for 41 days, and the circadian timing was calculated. Sensitivity to photic input was determined with light induced melatonin-suppression tests. Three intensities (500, 1.000, and 2,500 lux) were examined during three separate trials. The 2,500-lux trial resulted in 78% suppression, but the lesser intensity exposures were without substantial effect. Thus, the patient appeared to be subsensitive to bright light. A 4-week trial of daily melatonin administration (0.5 mg at 2100 hours) stabilized the endogenous melatonin and sleep rhythms to a period of 24.1 hours, albeit at a somewhat delayed phase A 14 month follow-up interview revealed thai the patient continued to take melatonin daily, and his sleep-wake schedule was stable to a near 24-hour schedule.
AB - The case of a 41-year-old sighted man with non-24 hour sleep wake syndrome is presented. A 7-week baseline assessment confirmed thai the patient expressed endogenous melatonin and sleep-wake rhythms with a period of 25.1 hours. We sought to investigate the underlying pathology and to entrain the patient to a normal sleep-wake schedule. No deficiency in melatonin synthesis was found. Furthermore, normal coupling between the melatonin and sleep propensity rhythms was documented using an 'ultrashort' sleep-wake protocol. Environmental light exposure was monitored for 41 days, and the circadian timing was calculated. Sensitivity to photic input was determined with light induced melatonin-suppression tests. Three intensities (500, 1.000, and 2,500 lux) were examined during three separate trials. The 2,500-lux trial resulted in 78% suppression, but the lesser intensity exposures were without substantial effect. Thus, the patient appeared to be subsensitive to bright light. A 4-week trial of daily melatonin administration (0.5 mg at 2100 hours) stabilized the endogenous melatonin and sleep rhythms to a period of 24.1 hours, albeit at a somewhat delayed phase A 14 month follow-up interview revealed thai the patient continued to take melatonin daily, and his sleep-wake schedule was stable to a near 24-hour schedule.
KW - Entrainment
KW - Light suppression
KW - Melatonin
KW - Non-24-hour sleep-wake syndrome
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U2 - 10.1093/sleep/19.7.544
DO - 10.1093/sleep/19.7.544
M3 - Article
C2 - 8899933
AN - SCOPUS:0029797433
SN - 0161-8105
VL - 19
SP - 544
EP - 553
JO - Sleep
JF - Sleep
IS - 7
ER -