National Sleep Foundation

Chapter 5: Circadian Rhythm Sleep Disorders

Assessment and Diagnosis

Assessment and diagnosis of non-24 hour sleep wake disorder

All circadian rhythm sleep disorders require a similar clinical assessment that includes a complete sleep history.

Aanalysis of the patient’s sleep-wake schedule for at least one week (preferably 14 days), using a sleep log or actigraph, should be used to identify potential variations in sleep timing.  For blind patients, a longer period of sleep log and actigraph recording is useful. It will also rule out other sleep disorders, such as insomnia, that are often mistaken for circadian rhythm sleep disorders.60 Polysomnography can also be used to rule out other sleep disorders.61  

It is also important, for sighted individuals, to rule out underlying psychiatric conditions such as depression or personality disorders, which may increase the risk for Non-24.62 63

People with Non-24 show a progressive “pattern of sleep and wake times [that] typically delay each day with a period longer than 24 hours.”64

References

60. Silber MH, Krahn LE, Morgenthaler TI. Circadian rhythm disorders. In: Silber MH, Krahn LE, Morgenthaler TI, eds. Sleep medicine in clinical practice. London, Eng: Taylor and Francis; 2004:253-276.

61.Reid KJ and Zee PC. “Circadian disorders of the sleep-wake cycle,” in Kryger M, Roth T, Dement W (ed.), Principles and Practice of Sleep Medicine (5th Edition), St. Louis: Elsevier Saunders, 2011, pages 470-482.

62. Reid KJ and Zee PC. “Circadian disorders of the sleep-wake cycle,” in Kryger M, Roth T, Dement W (ed.), Principles and Practice of Sleep Medicine (5th Edition), St. Louis: Elsevier Saunders, 2011, pages 470-482.

63. National Sleep Foundation (NSF), Non-24-Hour Sleep Wake Disorder: Associations with Depression, Arlington, VA: NSF, 2014. Online at: http://sleepfoundation.org/non-24/content/associations-depression.

64.  Reid KJ and Zee PC. “Circadian disorders of the sleep-wake cycle,” in Kryger M, Roth T, Dement W (ed.), Principles and Practice of Sleep Medicine (5th Edition), St. Louis: Elsevier Saunders, 2011, pages 470-482.