Association between delayed sleep phase and hypernyctohemeral syndromes: a case study (original) (raw)

Circadian Rhythm Sleep Disorders

There have been remarkable advances in our understanding of the molecular, cellular and physiological mechanisms underlying the regulation of circadian rhythms, as well as the impact of circadian dysfunction on health and disease. This information has transformed our understanding of the effect of circadian rhythm sleep disorders (CRSD) on health, performance and safety. CRSDs are caused by alterations of the central circadian time-keeping system, or a misalignment of the endogenous circadian rhythm and the external environment. In this section, we provide a review of circadian biology and discuss the pathophysiology, clinical features, diagnosis, and treatment of the most commonly encountered CRSDs in clinical practice.

Diagnosis of circadian rhythm sleep disorders

Jornal brasileiro de pneumologia : publicaça̋o oficial da Sociedade Brasileira de Pneumologia e Tisilogia, 2008

Insomnia and excessive sleepiness are common in the investigation of sleep-disordered breathing. Circadian rhythm sleep disorders are perhaps the most often overlooked conditions in the differential diagnosis of these symptoms. Circadian rhythm sleep disorders manifest as misalignment between the sleep period and the physical/social 24-h environmental cycle. The two most prevalent circadian rhythm sleep disorders are delayed sleep phase (common in adolescents) and advanced sleep phase (common in the elderly), situations in which the sleep period is displaced to a later or earlier time, respectively. It is important to keep these two disorders in mind, since they can be confused with insomnia and excessive sleepiness. However, there are nine possible diagnoses, and all nine are of clinical interest. Since light is the principal cue used in synchronizing the biological clock, blind individuals and night-shift/swing-shift workers are more prone to develop circadian rhythm sleep disorde...

Disorders of the sleep-wake cycle in adults

Postgraduate Medical Journal, 1998

Adults have an intrinsic body clock which regulates a complex series of rhythms including sleep and wakefulness, fatigue and cognitive ability. This endogenous clock naturally runs more slowly than the solar day and is entrained to a 24-h rhythm primarily by the alternation of light and darkness. Jet lag, shift-work sleep disorder, and some of the chronic insomnias are caused by a temporal discrepancy of the body clock relative to the surrounding environment and social network. The underlying mechanisms and general management are described. Both bright light and melatonin therapy have potential in the management of these disorders. Traditionally, bright light therapy has been used to alleviate the depression associated with seasonal affective disorder. Melatonin has received much illformed publicity, it being claimed that it is a panacea and an 'antiageing' treatment. Both of these treatment approaches are reviewed.

Workshop report. Circadian rhythm sleep–wake disorders: gaps and opportunities

Sleep, 2021

This White Paper presents the results from a workshop cosponsored by the Sleep Research Society (SRS) and the Society for Research on Biological Rhythms (SRBR) whose goals were to bring together sleep clinicians and sleep and circadian rhythm researchers to identify existing gaps in diagnosis and treatment and areas of high-priority research in circadian rhythm sleep–wake disorders (CRSWD). CRSWD are a distinct class of sleep disorders caused by alterations of the circadian time-keeping system, its entrainment mechanisms, or a misalignment of the endogenous circadian rhythm and the external environment. In these disorders, the timing of the primary sleep episode is either earlier or later than desired, irregular from day-to-day, and/or sleep occurs at the wrong circadian time. While there are incomplete and insufficient prevalence data, CRSWD likely affect at least 800,000 and perhaps as many as 3 million individuals in the United States, and if Shift Work Disorder and Jet Lag are i...

Circadian rhythm sleep disorders (CRSD)

Sleep Medicine Reviews, 2002

Circadian Rhythm Sleep Disorders (CRSD) are a group of sleep disorders characterized by a malsynchronization between a person's biological clock and the environmental 24-h schedule. These disorders can lead to harmful psychological and functional difficulties and are often misdiagnosed and incorrectly treated due to the fact that doctors are unaware of their existence. In the following review we describe the characteristics of CRSD, their diagnosis, treatment as well as their relationship to psychopathology, psychotropic drugs and head trauma. 

The endogenous circadian period in delayed sleep phase disorder

Journal of Sleep Research

Study objectives: The currently assumed aetiology for Delayed Sleep Phase Disorder (DSPD) is a delay of the circadian rhythm system. Clinicians have sought to use chronotherapy or bright light therapy, which has been shown to advance the circadian rhythm to correct the disorder. However, these treatments have achieved unreliable outcomes for DSPD patients, fuelling speculation that the disorder may be caused by a longer than normal circadian rhythm period length (i.e., tau). The present study investigated this proposed explanation using a 78-hour ultradian forced de-synchrony bed rest protocol. Design: During the protocol, twenty-minute sleep opportunities continuously alternated with 40 minutes of enforced wakefulness to simulate a series of 1-hour long “days”. Core temperature was monitored across the 78-hour protocol to identify the timing of the circadian rhythm and its tau. Setting: Flinders University Sleep Laboratory, Adelaide, South Australia. Participants: Six persons who m...

Circadian rhythm sleep disorders: An update

Sleep and Biological Rhythms, 2009

The primary symptom of circadian rhythm sleep disorders (CRSDs) is the inability to sleep during the desired sleep time. CRSDs are divided into two broad classes: (i) disorders not related to forced alterations of the sleep-wake schedule or light-dark cycle (including advanced sleep phase disorder [ASPD], delayed sleep phase disorder [DSPD], non-entrained type [NET], and irregular sleep-wake rhythm [ISWR]); and (ii) disorders related to forced alterations of the sleep-wake schedule or light-dark cycle (including shift work sleep disorder [SWSD], jet lag disorder [JLD], and CRSDs related to diseases and medications). DSPD and ASPD are the common primary circadian rhythm disorders. We discuss the recent developments in the pathogenesis, diagnosis, and management of CRSDs.

Delayed sleep-wake phase disorder in a clinical population: gender and sub-population differences

Sleep Science

Objective/Background: Delayed sleep-wake phase disorder (DSWPD) is defined by a delay in the major sleep episode relative to desired or required sleep and wake times. The objectives of this study were to evaluate DSWPD in our population and to compare it with similar clinical data, to analyse gender differences, and to identify possible subpopulations based on circadian timing and alignment. Patients/Methods: 162 consecutive DSWPD patients from a sleep clinic with a median age of 35.5 (24.0) years, 85 (52.5%) males were studied. Patient data were obtained from a clinical interview composed of socio-demographic, life events, daily habits, consumptions, and comorbidities data; and from diaries, actimetry, melatonin and PSG T1. The Dim Light Melatonin Onset (DLMO) was used to define circadian alignment or misalignment. Results: In our DSWPD cohort, there were gender differences for different age groups (p=0.028). Men were more likely to be single and women more likely to be married (p=0.034). In students, school failure was higher for women (p<0.001); for workers, absenteeism was higher in women (p=0.001). In the circadian aligned (compared to misaligned group), DLMO was later (p<0.001), sleep onset time (p=0.046) was later, total sleep time (p=0.035), and number of sleep cycles (p=0.018) were lower, as measured using PSG T1. Conclusions: In this clinical population, DSWPD is more prevalent in young men and in middle age women, although with no overall significant differences between genders. There are two different phenotypes of DSWPD: circadian misaligned and circadian aligned. Depression is prevalent in both groups. Better definition, classification and diagnostic criteria for DSWPD are still needed, and targeted therapeutical intervention should be evaluated.

Circadian Rhythm Sleep Disorder: Irregular Sleep Wake Rhythm Type

Sleep Medicine Clinics, 2009

Most physiologic, hormonal, and behavioral processes, most notably the sleep-wake cycle, exhibit nearly 24-hour (circadian) rhythms. These endogenous circadian rhythms are generated by the suprachiasmatic nucleus (SCN), a paired nucleus in the hypothalamus of the brain. 1-3 In humans, light is the strongest entraining agent for the circadian clock, 4 but nonphotic stimuli such as physical activity 5 and endogenous melatonin 6 also can alter the timing of circadian rhythms. In addition to its role in the timing and synchronization of biologic rhythms, the circadian pacemaker promotes alertness during the day and thus facilitates the consolidation of nocturnal sleep and daytime wakefulness across the 24hour cycle. 7-11 Significant changes in circadian regulation occur with aging and probably contribute to the higher prevalence of irregular sleep-wake rhythm disorder (ISWRD) in older adults. ISWRD is characterized by the relative absence of a circadian pattern in an individual's sleep-wake cycle. Common age-associated changes in circadian rhythm are the decreases in the amplitude of physiologic (eg, core body temperature) and hormonal circadian rhythms. 12-16 These age-related changes may be the result of degeneration or decreased neuronal activity of SCN neurons, decreased responsiveness of the circadian clock to entraining agents such as light, and decreased exposure to bright light and structured social and physical activity during the day. 17-20 Alterations in the central regulation of circadian rhythms when combined with the decreased levels of light exposure and social/physical activity levels probably contribute to the increased prevalence of ISWRD in older adults. This tendency toward increased prevalence of ISWRD is often further exaggerated in older adults who have neurodegenerative disorders, such as Alzheimer's disease. 21 Clinical Features and Diagnosis ISWRD is characterized by the lack of a clearly defined circadian sleep-wake rhythm in which sleeping and waking periods are distributed in at