Do I Have IH or NT2?

If you are uncertain whether you have idiopathic hypersomnia (IH) or narcolepsy type 2 (NT2), you are not alone. Sleep doctors are also asking this question, as sleep study results on the same patient often alternate between IH and NT2 diagnoses. Sleep researchers interested in hypersomnias are searching for more reliable ways of distinguishing between different types of hypersomnia.

Today, the number of SOREMPs in an MSLT study is the primary differentiator between an IH or an NT2 diagnosis. Unfortunately, the number of SOREMPs is not stable in many individuals, making it an unreliable test to distinguish between diagnoses. Given mounting evidence that some forms of IH are clinically indistinguishable from NT2, the idea of revising how we classify hypersomnia disorders into different diagnoses has become a topic of discussion.

In a recent article, “To split or to lump? Classifying the central disorders of hypersomnolence”, a team of global hypersomnia clinician-scientists proposes that NT2 and IH without long sleep time be combined into a single diagnostic category called “narcolepsy spectrum disorder.” Narcolepsy type 1 and idiopathic hypersomnia with long sleep time would remain distinct diagnoses. For more details on this proposal and the evidence supporting a change in classification, the free full text of the article can be found at this link.

For the proposed change to take effect, the new diagnostic criteria would have to be adopted in the next edition of the International Classification of Sleep Disorders, which will be ICSD-4. As of right now, there is no expected date for a future edition. There are likely to be additional proposals and many more discussions before any change to diagnostic criteria is adopted. For now, it is good to know that our hypersomnia community’s frustration with inconsistent diagnoses is recognized by the global clinician-researcher community and that they are trying to find a solution to the problem.

Share Post
FacebookTwitterLinkedInEmailShare

SomnusNooze Home Page

SomnusNooze Editions/Archives
Disclaimer

The contents of this website, including text, graphics and other material, are for informational purposes only. This website is not intended to be a substitute for professional legal or medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Always consult your own attorney or other legal advisor with any legal questions you may have. The Hypersomnia Foundation does not recommend or endorse any specific tests, physicians, lawyers, legal advisors, products, procedures, opinions or other information referenced on this website. Reliance on any information on this website is solely at your own risk.

The Hypersomnia Foundation makes no representations or warranties about the satisfaction of any government regulations requiring disclosure of information on prescription drug products. In no event shall The Hypersomnia Foundation be liable for any damages (including without limitation incidental and consequential damages) or costs (including without limitation attorney’s fees) based on any claim arising from the use of this website and/or its content.