Advanced Sleep Phase Disorder (ASPD), also known as the advanced sleep-phase type (ASPT) of circadian rhythm sleep disorder, is a condition that is characterized by a recurrent pattern of early evening (e.g. 7-9 PM) sleepiness and very early morning awakening (e.g. 2-4 AM). This sleep phase advancement can interfere with daily social and work schedules, and results in shortened sleep duration and excessive daytime sleepiness. The timing of sleep and melatonin levels are regulated by the bodys central circadian clock, which is located in the suprachiasmatic nucleus in the hypothalamus. Symptoms
Individuals with ASPD report being unable to stay awake until conventional bedtime, falling asleep early in the evening, and being unable to stay asleep until their desired waking time, experiencing early morning insomnia. When someone has advanced sleep phase disorder their melatonin levels and core body temperature cycle hours earlier than an average person. These symptoms must be present and stable for a substantial period of time to be correctly diagnosed. Diagnosis
Individuals expressing the above symptoms may be diagnosed with ASPD using a variety of methods and tests. Sleep specialists measure the patients sleep onset and offset, dim light melatonin onset, and evaluate Horne-Ostberg morningness-eveningness questionnaire results. Sleep specialists may also conduct a polysomnography test to rule out other sleep disorders like narcolepsy. Age and family history of the patient is also taken into consideration. Treatment
Once diagnosed, ASPD may be treated with bright light therapy in the evenings, or behaviorally with chronotherapy, in order to delay sleep onset and offset.
Treatment with sleep and wake scheduling and bright light therapy can be used to try to delay sleep phase to a more conventional time frame, however treatment of FASPS has proven largely unsuccessful. Bright light exposure in the evening (between 7:00 and 9:00), during the delay zone as indicated by the phase response curve to light, has been shown to delay circadian rhythms, resulting in later sleep onset and offset in patients with FASPS or other advanced sleep phase disorders. Discovery
In 1999, Louis Ptáček conducted a study at the University of Utah in which he coined the term familial advanced sleep phase disorder after identifying individuals with a genetic basis for an advanced sleep phase. The first patient evaluated during the study reported "disabling early evening sleepiness" and "early morning awakening"; similar symptoms were also reported in her family members. Consenting relatives of the initial patient were evaluated, as well as those from two additional families. The clinical histories, sleep logs and actigraphy patterns of subject families were used to define a hereditary circadian rhythm variant associated with a short endogenous (i.e. internally-derived) period. The subjects demonstrated a phase advance of sleep-wake rhythms that was distinct not only from control subjects, but also to sleep-wake schedules widely considered to be conventional. The subjects were also evaluated using the Horne-Östberg questionnaire, a structured self-assessment questionnaire used to determine morningness-eveningness in human circadian rhythms. The Horne-Östberg scores of first-degree relatives of affected individuals were higher than those of marry-in spouses and unrelated control subjects.