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Clinical Policy Bulletin:
Multiple Sleep Latency Test (MSLT)
Number: 0330


  1. Aetna considers the multiple sleep latency test (MSLT) medically necessary for either of the following 2 indications:

    1. For evaluation of symptoms of narcolepsy, to confirm the diagnosis; or
    2. For evaluation of persons with suspected idiopathic hypersomnia to help differentiate idiopathic hypersomnia from narcolepsy.

    Aetna considers MSLT experimental and investigational for all other indications because its effectiveness for indications other than the ones listed above have not been established, including (not an all-inclusive list): chronic fatigue syndrome; circadian rhythm disorders; insomnia, neurologic disorders other than narcolepsy; obstructive sleep apnea syndrome; and evaluation of the effectiveness of modafinil therapy in narcolepsy.

  2. Aetna considers repeat MSLT tests not medically necessary, unless:

    1. The initial test was invalid or uninterpretable; or
    2. The initial test is affected by extraneous circumstances or when study conditions were not present during initial testing; or
    3. The patient is suspected to have narcolepsy but earlier MSLT evaluation did not provide polygraphic confirmation.
  3. Aetna considers single nap studies experimental and investigational because a full MSLT is required for accurate diagnosis of narcolepsy.

  4. Aetna considers home MSLT experimental and investigational because home MSLT has not been proven to be equivalent to formal MSLT performed in a sleep laboratory.

See also CPB 0004 - Obstructive Sleep Apnea in Adults.


The multiple sleep latency test (MSLT) involves multiple trials during a day to objectively assess sleep tendency by measuring the number of minutes it takes the patient to fall asleep.  The patient may be instructed to lie down in a dark room, with permission or a suggestion given to sleep (MSLT) or to sit up in a dimly lit room and try to stay awake (maintenance of wakefulness test).  The MSLT is the better test for demonstration of sleep-onset rapid eye movement (REM) periods, a determination that is important in establishing the diagnosis of narcolepsy.  Parameters necessary for sleep staging (including 1 to 4 channels of EEG, EOG, and chin EMG) are recorded. 

According to AASM guidelines (Littner, et al., 2005), the MSLT is indicated as part of the evaluation of patients with suspected narcolepsy to confirm the diagnosis. The MSLT may be indicated as part of the evaluation of patients with suspected idiopathic hypersomnia to help differentiate idiopathic hypersomnia from narcolepsy. The MSLT is not routinely indicated in the initial evaluation and diagnosis of obstructive sleep apnea syndrome or in assessment of change following treatment with nasal CPAP (Littner, et al., 2005). The MSLT is not routinely indicated for evaluation of sleepiness in medical and neurological disorders (other than narcolepsy), insomnia, or circadian rhythm disorders. According to the AASM (Littner, et al., 2005), repeat MSLT testing may be indicated in the following situations: (a) when the initial test is affected by extraneous circumstances or when appropriate study conditions were not present during initial testing, (b) when ambiguous or uninterpretable findings are present, (c) when the patient is suspected to have narcolepsy but earlier MSLT evaluation(s) did not provide polygraphic confirmation.

Huang et al (2008) noted that the cause and pathogenesis of Kleine-Levin syndrome, a recurrent hypersomnia affecting mainly male adolescents, remain unknown, with only scant information on the sleep characteristics during episodes.  These investigators described findings obtained with polysomnography (PSG) and MSLT and correlation obtained between clinical and PSG findings from different episodes.  A total of 19 patients (17 males) were investigated with PSG and MSLT; 10 had data during both symptomatic episode and asymptomatic interval.  The analyses considered day of onset of symptoms and relationship between this time of onset and day of recording during the symptomatic period.  When PSG was performed early (before the end of the first half of the symptomatic period), an important reduction in slow wave sleep (SWS) was always present with progressive return to normal during the second half (with percentages very similar to those monitored during the asymptomatic period) despite persistence of clinical symptoms.  Rapid eye movement sleep remained normal in the first half of the episode but decreased in the second half: the differences between first and second half of episodes were significant for SWS (p = 0.014) and REM sleep (p = 0.027).  The overall mean sleep latency at MSLT was 9.51 +/- 4.82 mins and 7 of 17 patients had 2 or more sleep onset REM periods during the symptomatic period.  The authors concluded that important changes in sleep occur over time during the symptomatic period, with clear impairment of SWS at symptom onset.  However, MSLT is of little help in defining sleep problems and findings from the MSLT do not correlate with symptom onset.

Yeh and Schenck (2010) compared MSLT and Epworth sleepiness scale (ESS) for evaluating the effectiveness of modafinil in treating excessive daytime sleepiness in patients with narcolepsy.  A total of 10 consecutive patients with narcolepsy-with-cataplexy who were treated with 200 mg/day modafinil for more than 6 months were included in this study.  This comparative study was prompted by the requirement of the Bureau of National Health Insurance in Taiwan that modafinil users need to be followed-up with MSLTs every 6 to 12 months.  The mean age at onset of narcolepsy onset in these 10 patients was 11.8 +/- 3.3 years, and 8 (80 %) were male.  These investigators compared the differences in MSLT and ESS between baseline and follow-up at 6 to 12 months after starting modafinil therapy using paired-t tests.  Epworth Sleepiness Scale scores (p < 0.001) were considerably more sensitive than MSLT scores (p < 0.05) in documenting the effectiveness of modafinil and that improvements in MSLT scores were minimal and remained in the pathologically sleepy range.  These findings suggested that the ESS is a more sensitive and clinically meaningful tool to evaluate the effectiveness of modafinil in narcolepsy.

Mariman et al (2013) evaluated undiagnosed and co-morbid disorders in patients referred to a tertiary care center with a presumed diagnosis of chronic fatigue syndrome (CFS).  Patients referred for chronic unexplained fatigue entered an integrated diagnostic pathway, including internal medicine assessment, psychodiagnostic screening, physiotherapeutic assessment and PSG + MSLT.  Final diagnosis resulted from a multi-disciplinary team discussion.  Fukuda criteria were used for the diagnosis of CFS, DSM-IV-TR criteria for psychiatric disorders, ICSD-2 criteria for sleep disorders.  Out of 377 patients referred, 279 (74.0 %) were included in the study [84.9 % female; mean age of 38.8years (SD 10.3)].  A diagnosis of unequivocal CFS was made in 23.3 %.  In 21.1 %, CFS was associated with a sleep disorder and/or psychiatric disorder, not invalidating the diagnosis of CFS.  A predominant sleep disorder was found in 9.7 %, 19.0 % had a psychiatric disorder and 20.8 % a combination of both.  Only 2.2 % was diagnosed with a classical internal disease.  In the total sample, a sleep disorder was found in 49.8 %, especially obstructive sleep apnea syndrome, followed by psychophysiologic insomnia and periodic limb movement disorder.  A psychiatric disorder was diagnosed in 45.2 %; mostly mood and anxiety disorder.  The authors concluded that a multi-disciplinary approach to presumed CFS yielded unequivocal CFS in only a minority of patients, and revealed a broad spectrum of exclusionary or co-morbid conditions within the domains of sleep medicine and psychiatry.

However, an UpToDate review on “Clinical features and diagnosis of chronic fatigue syndrome” (Gluckman, 2014) does not mention the use of MSLT as a diagnostic tool.

CPT Codes / HCPCS Codes / ICD-9 Codes
CPT codes covered if selection criteria are met:
Other CPT codes related to the CPB:
95806 - 95807
95808 - 95811
ICD-9 codes covered if selection criteria are met:
327.11 - 327.12 Idiopathic hypersomnia with long sleep time
347.00 - 347.11 Cataplexy and narcolepsy [after obstructive sleep apnea has been ruled out by polysomnography] [MSLT is not covered for the evaluation of the effectiveness of modafinil therapy in narcolepsy]
ICD-9 codes not covered for indications listed in the CPB (not all-inclusive list):
307.42 Persistent disorder of initiating or maintaining sleep
327.23 Obstructive sleep apnea (adult)(pediatric)
327.30 - 327.39 Circadian rhythm sleep disorders
780.51 - 780.52 Insomnia
780.53 Hypersomnia with sleep apnea, unspecified
780.71 Chronic fatigue syndrome
Other ICD-9 codes related to the CPB:
327.00 – 327.10, 327.13 – 327.22, 327.24 – 327.29, 327.40 – 327.8 Organic sleep disorders
478.29 Other diseases of pharynx
780.50 Sleep disturbance, unspecified
780.55 Disruptions of 24-hour sleep-wake cycle, unspecified
780.56 Dysfunctions associated with sleep stages or arousal from sleep
780.57 Unspecified sleep apnea

The above policy is based on the following references:
  1. Thorpy MJ. The clinical use of the multiple sleep latency test. The Standards of Practice Committee of the American Sleep Disorders Association. Sleep. 1992;15(3):268-276. Available at: Accessed June 8, 2005.
  2. American Sleep Disorders Association Standards of Practice Committee, Polysomnography Task Force. Practice parameters for the indications for polysomnography and related procedures. Sleep. 1997;20(6):406-422. Available at: Accessed June 8, 2005.
  3. Chesson AL Jr, Ferber RA, Fry JM, et al. The indications for polysomnography and related procedures. An American Sleep Disorders Association Report. Sleep. 1997;20(6):423-487. Available at: Accessed June 8, 2005.
  4. Manni R, Tartara A. Evaluation of sleepiness in epilepsy. Clin Neurophysiol. 2000;111(Suppl 2):S111-S114.
  5. Guilleminault C, Pelayo R. Narcolepsy in children: A practical guide to its diagnosis, treatment and follow-up. Paediatr Drugs. 2000;2(1):1-9.
  6. Boon P, Pevernagie D, Schrans D. Hypersomnolence and narcolepsy: A pragmatic diagnostic neurophysiological approach. Acta Neurol Belg. 2002;102(1):11-18.
  7. Richert AC, Baran AS. A review of common sleep disorders. CNS Spectr. 2003;8(2):102-109.
  8. Chakravorty SS, Rye DB. Narcolepsy in the older adult: Epidemiology, diagnosis and management. Drugs Aging. 2003;20(5):361-376.
  9. Sateia MJ, Doghramji K, Hauri PJ, Morin CM. Evaluation of chronic insomnia. An American Academy of Sleep Medicine review. Sleep. 2000;23(2):243-308. Available at: Accessed June 8, 2005.
  10. American Academy of Sleep Medicine. Practice parameters for the evaluation of chronic insomnia. Sleep. 2000;23(2):237-241. Available at: Accessed June 8, 2005.
  11. Littner M, Johnson SF, McCall WV, et al. Practice parameters for the treatment of narcolepsy: An update for 2000. Sleep. 2001;24(4):451-466. Available at: Accessed June 8, 2005.
  12. Littner M, Hirshkowitz M, Kramer M, et al. Practice parameters for using polysomnography to evaluate insomnia: An update. Sleep. 2003;26(6): 754-760. Available at: Accessed June 8, 2005.
  13. Scottish Intercollegiate Guidelines Network (SIGN). Management of obstructive sleep apnoea/hypopnoea syndrome in adults. A national clinical guideline. SIGN Publication No. 73. Edinburgh, Scotland: SIGN; June 2003.
  14. Fong SY, Ho CK, Wing YK. Comparing MSLT and ESS in the measurement of excessive daytime sleepiness in obstructive sleep apnoea syndrome. J Psychosom Res. 2005;58(1):55-60.
  15. Littner MR, Kushida C, Wise M, et al. Practice parameters for clinical use of the multiple sleep latency test and the maintenance of wakefulness test. Sleep. 2005;28(1):113-121.
  16. Kushida CA, Littner MR, Morgenthaler T, et al. Practice parameters for the indications for polysomnography and related procedures: An update for 2005. Sleep. 2005;28(4):499-521.
  17. Wise MS. Objective measures of sleepiness and wakefulness: Application to the real world? J Clin Neurophysiol. 2006;23(1):39-49.
  18. Fronczek R, van der Zande WL, van Dijk JG, et al. Narcolepsy: A new perspective on diagnosis and treatment. Ned Tijdschr Geneeskd. 2007;151(15):856-861.
  19. Kasravi N, Legault G, Jewell D, Murray BJ. Minimal impact of inadvertent sleep between naps on the MSLT and MWT. J Clin Neurophysiol. 2007;24(4):363-365.
  20. Chen L, Ho CK, Lam VK, et al. Interrater and intrarater reliability in multiple sleep latency test. J Clin Neurophysiol. 2008;25(4):218-221.
  21. Huang YS, Lin YH, Guilleminault C. Polysomnography in Kleine-Levin syndrome. Neurology. 2008;70(10):795-801.
  22. Sullivan SS, Kushida CA. Multiple sleep latency test and maintenance of wakefulness test. Chest. 2008;134(4):854-861.
  23. Yeh SB, Schenck CH. Efficacy of modafinil in 10 Taiwanese patients with narcolepsy: Findings using the multiple sleep latency test and Epworth sleepiness scale. Kaohsiung J Med Sci. 2010;26(8):422-427.
  24. Mariman A, Delesie L, Tobback E, et al. Undiagnosed and comorbid disorders in patients with presumed chronic fatigue syndrome. J Psychosom Res. 2013;75(5):491-496.
  25. Gluckman SJ. Clinical features and diagnosis of chronic fatigue syndrome. Last reviewed January 2014. UpToDate Inc., Waltham, MA.

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Copyright Aetna Inc. All rights reserved. Clinical Policy Bulletins are developed by Aetna to assist in administering plan benefits and constitute neither offers of coverage nor medical advice. This Clinical Policy Bulletin contains only a partial, general description of plan or program benefits and does not constitute a contract. Aetna does not provide health care services and, therefore, cannot guarantee any results or outcomes. Participating providers are independent contractors in private practice and are neither employees nor agents of Aetna or its affiliates. Treating providers are solely responsible for medical advice and treatment of members. This Clinical Policy Bulletin may be updated and therefore is subject to change.
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