Smith-Magenis syndrome (SMS) (OMIM #182290) is a rare genetic disorder with a prevalence of 1 in 25 000 live births. Approximately 90% of SMS patients have harbored a 3.7 Mb interstitial 17p11.2 deletion involving the RAI1 gene, while 10% of cases have carried pathogenic variants of the RAI1 gene. SMS is characterized by sleep disturbance, intellectual impairment, developmental delay, craniofacial and cardiovascular anomalies, obesity, self injury, aggressive and autistic-like behaviors. Most SMS patients have sleep disorders such as short total sleep time, frequent night waking, short sleep onset, and early morning waking. The sleep disturbance may aggravate with age and persist throughout life. Three mechanisms have been delineated. The first concern was the abnormal secretion of melatonin, with high levels during daytime and low levels at night. Evaluation of the integrity of the intrinsically photosensitive retinal ganglion cell (ipRGC)/melanopsin system has found that SMS patients showed dysfunction in the sustained component of the pupillary light responses to blue light. Synchronization of daily melatonin profile and its photoinhibition are dependent on the activation of melanopsin. Dysfunction of the retina-melanin system may be one of the causes of melatonin spectrum disorders. Secondly, dysregulation of circadian rhythm gene expression has also been noted in mice and SMS patients. Finally, there may be association between sleep deprivation symptoms and DNA methylation patterns, which has provided new insights for SMS-associated sleep disorders and symptoms alike. Treatment for SMS-related sleep disorders is administered primarily through medications like melatonin tablets, which can alleviate insomnia-related sleep difficulties, in particular externalizing behavior in children. Researchers are also actively exploring other treatments for SMS currently.
Animals ; Circadian Rhythm ; Humans ; Melatonin ; Mice ; Sleep ; Sleep Wake Disorders/genetics* ; Smith-Magenis Syndrome/genetics*

OBJECTIVES: It is a paradox that sleep technicians are at risk of shift work sleep disorder to help diagnose other people's sleep disorder. Until now, there have been no guidelines for scheduling shifts for sleep technicians. The purpose of this study was to survey the current shift schedule of sleep technicians. METHODS: We performed a nationwide survey of work schedules for sleep laboratories. We sent email questionnaires to sleep technicians working in university-affiliated hospitals. Information regarding starting time and duration of shift, duty on-duty off pattern for the past month, and rotation and number of sleep technicians in the sleep labs were collected. RESULTS: We received responses from 29 sleep labs. Among the 25 labs which had designated sleep technicians, three labs had night shift schedules mixed with day work on a weekly basis and the remaining 22 labs had night only shift schedule. In cases of night only shift schedules, 11 labs alternated from night shift to day shift works or vice versa every 3 months to 3 years, while the remaining 11 labs had fixed schedules without daytime rotation. Number of night shift was four or less per week, with shift durations of 9–19 hours. CONCLUSIONS: The current policies regarding scheduling shifts varied vastly depending on individual sleep labs. We found that some labs had shift schedules with long work time, quick returns, or permanent night shifts, which are generally not recommended. Further studies are needed to develop consensus guidelines for scheduling shift of sleep technicians.
Appointments and Schedules ; Consensus ; Electronic Mail ; Korea ; Sleep Disorders, Circadian Rhythm ; Sleep Wake Disorders

OBJECTIVE: This study aimed to evaluate psychometric properties of the Munich ChronoType Questionnaire (MCTQ) in a sample of Korean older adults. METHODS: One-hundred ninety two participants aged 65 and over completed interview-based questionnaires about chronotype, insomnia, depression, and anxiety. Additionally, a small subset of subjects completed a 7-day sleep diary and actigraphy measurements. RESULTS: Morningness-Eveningness Questionnaire (MEQ) scores were significantly negatively correlated with Midpoint of sleep on free days corrected for sleep debt accumulated through weekdays (MSFsc) (r=-0.45, p < 0.01) assessed by the MCTQ. MSFsc using the MCTQ was significantly positively correlated with MSFsc assessed by both the sleep diary (r=0.74, p < 0.05) and actigraphy (r=0.76, p < 0.05). Additionally, MSFsc assessed by the MCTQ was significantly positively correlated with insomnia (r=0.26, p < 0.01), depression (r=0.25, p < 0.01), and anxiety (r=0.18, p < 0.05). Finally, based on MEQ scores, we derived a cut-off score for the MCTQ that distinguishes morning type and other types (intermediate/evening types) in older adults. CONCLUSION: The results of these studies supported the validity of the MCTQ in Korean older adults. Additionally, while sleep rhythms in elder adults may be more advanced, eveningness tendency may be still important and indicative of sleep and psychological disturbance.
Actigraphy ; Adult* ; Anxiety ; Circadian Rhythm ; Depression ; Geriatric Assessment ; Geriatric Psychiatry ; Humans ; Psychometrics ; Sleep Initiation and Maintenance Disorders ; Sleep Wake Disorders

PURPOSE: The purpose of this study was to identify the factors affecting shiftwork tolerance among nurses and provide basic data, ultimately, in formulating a plan for improving their shiftwork tolerance. METHODS: The participants were 317 nurses who were working at three general hospitals in Daejeon and Seoul. Data analyzed t-test, ANOVA, correlation analysis, and regression analysis using SPSS 20.0 program. RESULTS: As for the sub-areas of shiftwork tolerance for the respondents, more than a half of nurses working at shifts suffered from insomnia, felt drowsy, complained of chronic fatigue, and were at the anxious and depressed state. Shiftwork tolerance differed by the daily intake of coffee and exercise. Shiftwork tolerance was significantly positively correlated with sleep-wake habits, hardiness, and flexibility and negatively correlated with a languidity. Regression analysis revealed that shiftwork tolerance was affected by age, sleep-wake habits, languidity, flexibility, and hardiness. CONCLUSION: To put the results, nurses had shiftwork tolerance affected by sleep-wake habits, languidity, and hardiness. It is therefore necessary to make a scheme for allowing nurses to improve hardiness and flexibility and decrease the languidity with the objective of improving their shiftwork tolerance.
Circadian Rhythm ; Coffee ; Fatigue ; Hospitals, General ; Pliability ; Seoul ; Sleep Initiation and Maintenance Disorders ; Sleep Wake Disorders ; Surveys and Questionnaires ; Work Schedule Tolerance

OBJECTIVE: Concern that disturbances of sleep and light exposures at night might increase cancer risks have been expressed, but little actual exposure data has been collected. Measurements from a representative population sample were examined to understand the magnitude of in-bed light exposure at night and possible correlates. METHODS: From 1990 to 1994, a home survey of sleep disorders among adults ages 40-64 was conducted in the City of San Diego California, using stratified representative sampling techniques. Along with questionnaires, sleep logs, and 3-night wrist activity and pulse oximetry measures, bedside illumination was measured with a computer recording system. Questionnaires included the CESD depression scale and a scale of symptoms typical of winter depression. RESULTS: Complete data were available from 286 men and women, whose mean in-bed intervals averaged 7 hours and 42 minutes. The mean room illumination during the first part of the night was mean 12.7 lux (median 3.2 lux) and during the last 2 hours in bed averaged 28.7 lux (median 18.9 lux). Nocturnal light exposure was positively correlated with age, male gender, summer season, time in bed, wake-up time, and depressive symptoms. CONCLUSION: Complex bi-directional interactions may take place between sleep disturbances, depression, time in bed, wake-up-time, and in-bed illumination. The most crucial light exposures appear to occur in the last 2 hours in bed, largely after dawn, so daylight exposure may be an important factor.
Adult ; California ; Circadian Rhythm ; Depression ; Female ; Humans ; Lighting ; Male ; Oximetry ; Photometry ; Surveys and Questionnaires ; Seasons ; Sleep Wake Disorders ; Wrist

People called night owls habitually have late bedtimes and late times of arising, sometimes suffering a heritable circadian disturbance called delayed sleep phase syndrome (DSPS). Those with DSPS, those with more severe progressively-late non-24-hour sleep-wake cycles, and those with bipolar disorder may share genetic tendencies for slowed or delayed circadian cycles. We searched for polymorphisms associated with DSPS in a case-control study of DSPS research participants and a separate study of Sleep Center patients undergoing polysomnography. In 45 participants, we resequenced portions of 15 circadian genes to identify unknown polymorphisms that might be associated with DSPS, non-24-hour rhythms, or bipolar comorbidities. We then genotyped single nucleotide polymorphisms (SNPs) in both larger samples, using Illumina Golden Gate assays. Associations of SNPs with the DSPS phenotype and with the morningness-eveningness parametric phenotype were computed for both samples, then combined for meta-analyses. Delayed sleep and "eveningness" were inversely associated with loci in circadian genes NFIL3 (rs2482705) and RORC (rs3828057). A group of haplotypes overlapping BHLHE40 was associated with non-24-hour sleep-wake cycles, and less robustly, with delayed sleep and bipolar disorder (e.g., rs34883305, rs34870629, rs74439275, and rs3750275 were associated with n=37, p=4.58E-09, Bonferroni p=2.95E-06). Bright light and melatonin can palliate circadian disorders, and genetics may clarify the underlying circadian photoperiodic mechanisms. After further replication and identification of the causal polymorphisms, these findings may point to future treatments for DSPS, non-24-hour rhythms, and possibly bipolar disorder or depression.
Bipolar Disorder ; Case-Control Studies ; Comorbidity ; Depression ; Genetics ; Haplotypes ; Humans ; Melatonin ; Phenotype ; Photoperiod ; Polymorphism, Single Nucleotide ; Polysomnography ; Sleep Wake Disorders, Circadian Rhythm ; Strigiformes*

PURPOSE: The purpose of this study was to identify quality of sleep and health-promoting behaviors in rotating-shift nurses and to explore the influence of health promoting behaviors on quality of sleep. METHOD: Participants were 161 staff nurses working in an irregular three shift system in one of three general hospitals located in Kyungpook province. Data were collected using the Pittsburgh Sleep Quality Index and the Health Promoting Lifestyle Profile-II and were analyzed using hierarchical multiple regression analysis. RESULTS: The majority of the participants had very poor quality of sleep and performed a low level of health promoting behaviors. In terms of health promoting behaviors, nutrition and stress management significantly influenced quality of sleep of these nurses. CONCLUSION: Results indicate the importance of encouraging rotating-shift nurses to enhance their health promoting behaviors in order to improve quality of sleep.
Circadian Rhythm ; Gyeongsangbuk-do ; Health Promotion ; Health Status ; Hospitals, General ; Life Style ; Sleep Wake Disorders

Alcohol has been used as sedatives historically. The effect of alcohol on sleep is different according to its dose, timing of ingestion, and drinking frequency. Sleep problems may play a role in the development and course of alcohol-related disorders. Insomnia in alcohol-dependent patients is common and early treatment of insomnia may reduce the rate of relapse. Sleep apnea, restless legs syndrome, periodic limbs movement disorder, and altered circadian rhythm may be more frequent in this patients. Management of sleep and alcohol problems is important in treating alcohol-related disorder and sleep disorders, respectively.
Alcohol-Related Disorders ; Circadian Rhythm ; Drinking ; Eating ; Extremities ; Humans ; Hypnotics and Sedatives ; Movement Disorders ; Recurrence ; Restless Legs Syndrome ; Sleep Apnea Syndromes ; Sleep Wake Disorders ; Sleep Initiation and Maintenance Disorders

A total of 85 sleep disorders are described in the International Classification of Sleep Disorders, 2nd ed. Knowledge about those sleep disorders will be essential not only for good and healthy sleep but also for maintaining adequate physical and mental function during daytime. Sleep medicine has a relatively short history compared to other medical fields, thus, many sleep disorders are not familiar to the general public and even to physicians. In this small review about various sleep disorders, I will briefly introduce basic concepts about insomnia, sleep-related breathing disorder, hypersomnia, circadian rhythm sleep disorders, parasomnia and sleep-related movement disorders. These sleep disorders are frequently encountered in clinical settings, and understanding them will give us insight about the basic mechanism of sleep-wake states.
Classification ; Diagnosis ; Disorders of Excessive Somnolence ; Movement Disorders ; Parasomnias ; Respiration ; Sleep Wake Disorders* ; Sleep Disorders, Circadian Rhythm ; Sleep Initiation and Maintenance Disorders

Sleep comprises one third of human life and is very important for maintaining healthy mental and physical states. Sleep disorders disturbing normal sleep are very common and may induce serious consequences. Sleep disorder medicine is based on the concept of two different states (waking and sleep) of the human brain. The problems of the waking conscious state affect sleep and problems during sleep also affect daytime mental and physical activities. The common symp-toms of patients with sleep disorders are excessive daytime sleepiness, a decrease in alertness, and fatigue. To detect sleep disorders, we should understand the physiology of normal sleep. Normal sleep consists of non-rapid eye movement (75% to 80%) and rapid eye movement (20% to 25%) sleep. The International Classification of Sleep Disorders second edition lists 77 different sleep disorders divided into 8 categories. Clinical approaches to sleep disorder patients should include detailed history taking including sleep history, a sleep questionnaire, sleep diary, physical examination including the nasal/oral cavities and airway, and neurological/psychological examination. The common sleep disorders are obstructive sleep apnea, insomnia, narcolepsy, restless legs syndrome, rapid eye movement sleep behavior disorder, and circadian rhythm sleep disorder. We should learn the characteristic clinical features of each sleep disorder and how to detect and treat them. We need a more active effort to educate physicians about sleep disorder medicine and should try large sample, long-term, and prospective studiesto reveal the pathophysiology and enhance the treatment of sleep disorders. Sleep disorders are common, serious, and treatable. However, most patients with sleep disorders are underdiagnosed and not treated appropriately due to lack of knowledge of sleep disorder medicine. The Ministry of Health and Welfare of South Korea should focus more attention on and provide more support for timely diagnosis and treatment of sleep disorders.
Brain ; Circadian Rhythm ; Eye Movements ; Fatigue ; Humans ; Motor Activity ; Narcolepsy ; Physical Examination ; Surveys and Questionnaires ; REM Sleep Behavior Disorder ; Republic of Korea ; Restless Legs Syndrome ; Sleep Apnea, Obstructive ; Sleep Initiation and Maintenance Disorders ; Sleep Wake Disorders ; Sleep, REM