idiopathic hypersomnia (IH)« Back to Glossary IndexIdiopathic hypersomnia (IH) is a neurological disorder characterized by excessive daytime sleepiness (often with associated cognitive dysfunction), despite getting a full night’s sleep or longer. People with IH may also experience difficulty awakening, sleep drunkenness, automatic behaviors, and symptoms related to the autonomic nervous system, such as feeling lightheaded when standing up quickly. Read more About IH.Related Articles: Hypersomnia Foundation Hosted the Largest Patient-Centered Sleep Conference Ever This JuneIn Case You Missed It! – June 2022Top HF ResourcesVirtual HF Conference Is Now Free. Register Today!In Case You Missed It! – May 2022CHARLOTTE, NC: Accredited Continuing Education Dinner SymposiumNews From World Sleep 2022 in Rome!In Case You Missed It! – April 2022In Case You Missed It! – March 2022Guide to Survey DesignGuide for ResearchersGuide for Sleep & Research Study CentersConsiderations for ProfessionalsIn Case You Missed It! – January 2022CHARLOTTE, NC - HF ConferenceIn Case You Missed It! – December 2021VIRTUAL MEET & GREET - "We're in This Together!"Let’s Kick Off Giving Tuesday Together!In Case You Missed It! – November 2021Our Partners