Diagnosing IH
Idiopathic Hypersomnia (IH) is a unique medical condition that is different from other disorders
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The International Classification of Sleep Disorders (3rd Edition, ICSD-III)
The ICSD-III helps objectively diagnose patients and provides more information for developing an appropriate treatment plan. For a diagnosis of IH, the following must be met1:
ICD-10-CM codes2: G47.11 (with long sleep), G47.12 (without long sleep)
Excessive daytime sleepiness
() daily for ≥3 months
is not present
shows <2 or no if the latency on the preceding was ≤15 minutes
Insufficient sleep syndrome is ruled out
At least one of the following:
- shows a mean sleep latency of ≤8 minutes
- Total 24-hour sleep time is ≥660 minutes (typically
12-14 hours ) on 24-hour monitoring (performed after correction of chronic sleep deprivation), or by wrist actigraphy in association with a sleep log (averaged over at least 7 days with unrestricted sleep)
Hypersomnolence and/or findings are not better explained by another sleep disorder, other medical or psychiatric disorders, or use of drugs or medication
- Excessive daytime sleepiness
() daily for ≥3 months - is not present
- shows <2 or no if the latency on the preceding was ≤15 minutes
- Insufficient sleep syndrome is ruled out
At least one of the following:
- shows a mean sleep latency of ≤8 minutes
- Total 24-hour sleep time is ≥660 minutes (typically
12-14 hours ) on 24-hour monitoring (performed after correction of chronic sleep deprivation), or by wrist actigraphy in association with a sleep log (averaged over at least 7 days with unrestricted sleep)
Hypersomnolence and/or findings are not better explained by another sleep disorder, other medical or psychiatric disorders, or use of drugs or medication
Additional supportive clinical features include1:
Severe and prolonged
Long, unrefreshing naps (>1 hour)
High sleep efficiency (>90%) on the preceding
Get more guidance on assessing and diagnosing IH with this guide
Knowing the key symptoms and utilizing sleep testing can increase confidence in the diagnosis of IH
Assess symptoms
is an essential feature of IH1
- Understanding key symptoms and other aspects of medical history is crucial when evaluating patients who present with
In addition to EDS, patients with IH commonly report the following symptoms:
Profound sleep inertia
Prolonged difficulty waking up, with repeated returns to sleep1
Ask your patient: Is it extremely difficult for you, or even impossible, to wake up in the morning without several alarm calls or the help of someone close?3
Long unrefreshing naps
Of the patients who do nap during the day, the majority report taking naps longer than 60 minutes and many do not find them to be restorative1,4
Ask your patient: Do you feel refreshed after you nap?3
Prolonged sleep time
≥11 hours total sleep time per 24 hours1
Ask your patient: If you had no obligations or commitments to consider, how long would you prefer to sleep at night?3
Cognitive impairment
Attention deficits, difficulty concentrating, memory loss1,5
Ask your patient: Is it hard for you to sustain focus or remember things?2,5
Initiate Sleep Testing
If no clear cause of sleepiness is found or sleepiness persists after correction of other factors, sleep testing with polysomnography
PSG
A sleep test that records sleep stages and physiologic parameters1,6
is important in the workup of patients with possible IH and is used to exclude other causes of 1
MSLT
A series of five 20-minute naps at 2-hour intervals that measure how quickly a patient falls asleep and the number of SOREMPs7
If a patient has an ≤8 min and <2 on the , consider a diagnosis of IH1
“Getting a diagnosis was a relief. I was like, oh my gosh, I finally know what is wrong with me. There's actually really something diagnosable that's wrong with me.”—Patient living with IH
Want to see how the 5 key IH symptoms can overlap with other conditions?
References:
- American Academy of Sleep Medicine. International Classification of Sleep Disorders. 3rd ed. Darien, IL: American Academy of Sleep Medicine; 2014.
- ICD-10-CM tabular list of diseases and injuries. Centers for Medicare & Medicaid Services website. https://www.cms.gov/Medicare/Coding/ICD10/2020-ICD-10-CM. Accessed October 21, 2022.
- Dauvilliers Y. Idiopathic hypersomnia severity scale. 2018. Accessed October 21, 2022. http://links.lww.com/WNL/A854.
- Arnulf I, Leu-Semenescu S, Dodet P. Precision medicine for idiopathic hypersomnia. Sleep Med Clin. 2019;14(3):333-350.
- Vernet C, Leu-Semenescu S, Buzare MA, Arnulf I. Subjective symptoms in idiopathic hypersomnia: beyond excessive sleepiness. J Sleep Res. 2010;19(4):525-534.
- Rundo, JV, Downey R. Polysomnography. In: Handbook of Clinical Neurology. Vol 160. Elsevier; 2019:381-392.
- Littner MR, Kushida C, Wise M. Practice Parameters for Clinical Use of the Multiple Sleep Latency Test and the Maintenance of Wakefulness Test: An American Academy of Sleep Medicine Report. Sleep: 2005;28(1):113-121.