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ICSD-2 Classification

IV. Circadian Rhythm Sleep Disorders

• Circadian Rhythm Sleep Disorder, Delayed Sleep Phase Type (Delayed Sleep Phase Disorder)

• Circadian Rhythm Sleep Disorder, Advanced Sleep Phase Type (Advanced Sleep Phase Disorder)

• Circadian Rhythm Sleep Disorder, Irregular Sleep Wake Type

• Circadian Rhythm Sleep Disorder, Free-Running Type (Nonentrained Type)

• Circadian Rhythm Sleep Disorder, Jet Lag Type

• Circadian Rhythm Sleep Disorder, Shift Work Type

• Circadian Rhythm Sleep Disorder Due to Medical Condition

• Other Circadian Rhythm Sleep Disorder (Circadian Rhythm Disorder, NOS)

• Other Circadian Rhythm Sleep Disorder Due to Drug or Substance

• Other Circadian Rhythm Sleep Disorder Due to Alcohol Use

General Criteria for CRSD

• Persistent or recurrent pattern of sleep disturbance primarily due to one of the following:

– Alterations of the circadian timekeeping system

– Misalignment between the endogenous circadian rhythm and exogenous factors that affect the timing or duration of sleep

• Leads to insomnia +/- EDS

• Associated impairment of social, occupational or other areas of functioning

Delayed Sleep Phase Disorder

• Diagnostic Criteria

– Delay in the phase of major sleep period in relation to the desired sleep and wake-up times (can’t fall asleep and wake-up at appropriate times)

– Normal sleep when allowed to choose their preferred schedule and remains entrained to 24 hr cycle

– Sleep log or actigraphy for at least 7 days demonstrates a stable delay in timing of sleep

• Delay in the core body temperature nadir and DLMO can be helpful to confirm

• Common in adolescents and young adults (7-16%)

• Attempts to fall asleep may result in conditioned insomnia

• Polymorphism of the hPer3 gene is associated

Advanced Sleep Phase Disorder

• Diagnostic Criteria

– Advance in the sleep phase of the major sleep period in relation to the desired sleep and wake-up times as evidence by inability to stay awake until the desired clock time together with an inability to remain asleep until the desired and socially accepted wake-up time

– Normal sleep quality and duration when allowed to choose their preferred schedule and remains entrained to 24 hr cycle

– Sleep log or actigraphy for at least 7 days demonstrates a stable advance in timing of habitual sleep period

• advance in the timing of the core body temperature nadir and DLMO can be helpful to confirm

• Must be distinguished from normal sleepers who advance their phase without consequence

• 1% prevalence in middle age adults and increases with age

• Several families identified, mutation in hPer2 gene in 1 family

Circadian Rhythm Sleep Disorder Irregular Sleep Wake Type

• Diagnostic Criteria

– Complaint of insomnia, EDS or both

– Sleep log or actigraphy for at least 7 days demonstrate multiple irregular sleep bouts (at least 3) during a 24 hr period

– TST for 24 hrs is normal for age

• Napping is prevalent

Circadian Rhythm Sleep Disorder Free-Running Type

• Diagnostic Criteria

– Complaint of insomnia or EDS related to abnormal synchronization between the 24 hr light-dark cycle and the endogenous circadian rhythm of sleep and wake propensity

– Sleep log or actigraphy for at least 7 days demonstrates a pattern of sleep and wake times that typically delays each day with a period > 24 hrs

– Monitoring for > 7 days is recommended to establish the pattern

• >50% of blind people (but totally blind people can have functioning retinohypothalamic tract)

Circadian Rhythm Sleep Disorder Jet Lag Type

• Diagnostic Criteria

– Complaint of insomnia or EDS associated with transmeridian travel across at least 2 time zones

– Associated impairment of daytime function, malaise, or somatic symptoms such as GI disturbance within 1-2 days of travel

• Eastward travel is more difficult to adjust to since it requires advancing the sleep phase

• Other factors related to air travel (sleep deprivation, air quality and pressure, use of etoh and caffeine) may contribute to sxs

• General rule:

– it takes 1 day to adjust for every time zone crossed

– however, traveling more than 6 time zones can lead to a circadian rhythm shift in the opposite direction causing prolonged symptoms

• If symptoms persist, jet lag may have converted into psychophysiological insomnia

Circadian Rhythm Sleep Disorder Shift Work Type

• Diagnostic Criteria

– Complaint of insomnia or EDS that is temporally associated with a recurring work schedule that overlaps the usual sleep time

– At least one month

– Sleep log or actigraphy for at least 7 days demonstrates disturbed circadian and sleep time misalignment

• Night and early morning workers typically have reduced TST by 1-4 hrs and complain of poor sleep quality

• Reduced alertness may lead to decreased job performance or accidents

• EDS appears to be a combination of reduced TST and reduction of the circadian alerting signal when working at night

• Many workers try to go back to a normal schedule when not on shift, which interferes with adjustment of the circadian rhythm

• PSG not required, but if it is done, should be performed during the patient’s habitual sleep period

Circadian Rhythm Sleep Disorder Due to Medical Condition

• Diagnostic Criteria

– Complaint of insomnia or EDS related to alterations of the circadian timekeeping system or misalignment between the endogenous circadian rhythm and exogenous factors that affect the timing or duration of sleep

– Underlying medical or neurological problem accounts for this

– Sleep log or actigraphy for at least 7 days demonstrates disturbed or low amplitude circadian rhythmicity

• Dementia, Parkinson’s, Blindness (if free-running code as that instead), hepatic encephalopathy

Reference:

The International Classification of Sleep Disorders, Second Edition. The American Academy of Sleep Medicine Press, 2005. Can be purchased at the AASM store online!