A 25-year-old male presented to our sleep medicine clinic with a chief complaint of difficulty falling and staying asleep present for the past couple of years. He estimated his bedtime to be between midnight and 03:00 and sleep latency of up to 3 hours, with several nighttime awakenings, and wake time of around 10:00. He took naps 2 to 3 times a week, at random times of the day. He spent his days at home playing video games and watching television, and did not go outside the house much. He also reported a history of loud snoring and witnessed apneas during sleep, as well as non-refreshing sleep and excessive daytime sleepiness, although the Epworth Sleepiness Scale (ESS) was 7/24. Past medical history included stable depression, Asperger syndrome and history of attention deficit hyperactivity disorder as a child. Current medications included sertraline. Physical exam revealed an overweight male with body mass index of 32 and a crowded oral airway (Friedman class 3).
Because actigraphy was not readily available at the time of his visit, he was asked to keep sleep logs. Due to the risk for obstructive sleep apnea, a polysomnogram was completed, which showed poor sleep efficiency of 53%, with prolonged latency to persistent sleep of 180 minutes (lights out at 22:10) and severe obstructive sleep apnea (apnea-hypopnea index = 43.0) with excessive central apneas (central apnea index = 10.3). A subsequent titration found that continuous positive airway pressure (CPAP) 8 cm water effectively treated obstructive and central sleep apnea.
At one-month follow-up he reported using CPAP every night and felt improvements in excessive daytime sleepiness (ESS decreased to 5/24), and had more energy and motivation to exercise. He did not bring his sleep logs for review, but estimated his bedtime to be 22:00 and sleep latency of 20 minutes, reduced nighttime awakenings to 1 to 2 a night, wake time between 07:00 and 11:00, and was no longer taking naps. CPAP data download was obtained, which showed use of CPAP on 100% of the nights for an average of 9 h 15 min; residual AHI was not available on his machine. Detailed view of CPAP use is shown in Figure 1.
Detailed CPAP data download.
Horizontal bars represent CPAP use.
Detailed CPAP data download. Horizontal bars represent CPAP use.
QUESTION: Based on review of the CPAP data download, you suspect this patient has a circadian rhythm sleep-wake disorder causing his chief complaint of insomnia. This disorder is MOST commonly seen in which of the following group of patients?
Healthy adolescents and young adults
Totally blind individuals
Institutionalized elderly with neurodegenerative disorders
ANSWER: B. Totally blind individuals
The detailed view of CPAP use shows a progressive delay of the sleep period by about one hour a day with relatively stable sleep duration, which is characteristic of non-24-hour sleep-wake rhythm disorder (N24SWD). In this case, CPAP use is a surrogate marker of sleep, although if sleep latency is prolonged, it may not accurately reflect sleep onset.
Previously called Free-Running Type, N24SWD is defined by the International Classification of Sleep Disorders, Third Edition (ICSD-3) as a history of insomnia, excessive daytime sleepiness, or both, which alternate with asymptomatic episodes, due to misalignment between the 24-hour light-dark cycles and the non-entrained endogenous circadian rhythm of sleep-wake propensity, with symptoms persisting for at least three months.1 ICSD-3 requires daily sleep logs and actigraphy for at least 14 days that typically demonstrate a circadian period longer than 24 hours. Our patient was asked to complete sleep logs which he did not, and the CPAP data compliance log provided reliable information as to the timing of his sleep cycle.
Most individuals with N24SWD are totally blind, due to non-functional photosensitive retinal ganglion cells resulting in an absence of photoperiod information being transmitted through the retinohypothalamic pathway. N24SWD can also be seen in sighted individuals, those with a history of intellectual disability, autism spectrum disorder, dementia, or delayed sleep-wake disorder with decreased light and social exposure or who have undergone chronotherapy.1 Our patient has a history of Asperger syndrome and reported minimal light and social exposure, predisposing him to the development of N24SWD (Answer B is correct).
Delayed Sleep-Wake Phase Disorder is more common in healthy adolescents and young adults due to a biological delay of the circadian rhythm and behavioral preference (Answer A is not correct). Irregular Sleep-Wake Rhythm Disorder is observed in institutionalized elderly and children with neurodevelopmental disorders (Answer C is not correct). Advanced age is a risk factor for Advanced Sleep-Wake Phase Disorder (Answer D is not correct).
Timed melatonin administration may be effective in entraining the circadian rhythm in blind individuals and is considered a guideline in the American Academy of Sleep Medicine (AASM) practice parameters.2 Circadian phase shifting with a combination of appropriately timed melatonin administration, timed bright light exposure, and prescribed sleep and wake scheduling may be effective in circadian phase shifting in sighted individuals, and all are considered options in the AASM practice parameters.2 Tasimelteon was recently approved for treatment of N24SWD and has been shown to improve sleep onset and maintenance in blind patients with N24SWD.3 Tasimelteon is a selective agonist at melatonin MT1 receptors (associated with sleep induction) and MT2 receptors (associated with circadian rhythm regulation). However, the cost of this drug may be prohibitive to many patients.
This was not an industry supported study. Christopher L. Drake has received funding from Merck, Teva, Pernix and Jazz. He has consulted for Teva and Merck. He has been a speaker for Teva, and Merck. Virginia Skiba has no financial conflicts of interest.
American Academy of Sleep Medicine
continuous positive airway pressure
Epworth Sleepiness Scale
International Classification of Sleep Disorders, Third Edition
Non-24-Hour Sleep-Wake Rhythm Disorder
Skiba V, Drake C. How the CPAP download unexpectedly helped a young man with a sleeping problem. J Clin Sleep Med 2015;11(9):1066–1068.
American Academy of Sleep Medicine. International classification of sleep disorders. 3rd ed. Darien, IL: American Academy of Sleep Medicine, 2014.
Morgenthaler TI, Lee-Chiong T, Alessi C, et al., authors. Standards of Practice Committee of the AASM. Practice parameters for the clinical evaluation and treatment of circadian rhythm sleep disorders. Sleep. 2007;30:1445–59. [PubMed Central][PubMed]
Johnsa JD, Neville MW, authors. Tasimelteon: a melatonin receptor agonist for non-24-hour sleep-wake disorder. Ann Pharmacother. 2014;48:1636–41. [PubMed]