What is Idiopathic Hypersomnia?

What is Idiopathic Hypersomnia? “Idiopathic” means the medical profession does not know

what causes the symptom. “Hypersomnia” means you are excessively sleepy. So Idiopathic

Hypersomnia means you are excessively sleepy but we do not know why or what is causing you to be sleepy. If you consult a Sleep Medicine specialist, they will request that you undergo a night time sleep study followed by a Mean Sleep Latency Test (MSLT). The MSLT is a multiple nap test the following day after your night time sleep study that quantifies how sleepy you are by allowing you to take 4 or 5 naps each spaced by two hours. The Mean Sleep Latency (MSL) is the average of how quickly you fall asleep in each nap. A Mean Sleep Latency less than 5 minutes is considered pathologic and a MSL less than 8 minutes is considered abnormal.

Patients with Idiopathic Hypersomnia typically have Mean Sleep Latency’s longer than patient with Narcolepsy. The MSLT has recently come under more scrutiny due to lack of test- retest reliability. Patients with Idiopathic Hypersomnia do not have REM sleep documented in their naps unlike patients with Narcolepsy. These patients are less likely to have “sleep attacks” but feel unrested throughout the day. They struggle with “sleep inertia” in the mornings making it very hard to get out of bed. They have brain fog and misplace things and forget things. If they nap it typically is not refreshing and they have a hard time getting up from a nap.

Idiopathic Hypersomnia patients can also struggle with dysautonomia which is dysfunction of the autonomic nervous system presenting with orthostatic intolerance or postural orthostatic tachycardia.

Many of these symptoms above can overlap with Chronic Fatigue Syndrome/Myalgic

Encephalitis, or Long Covid all of which, including Idiopathic Hypersomnia, are commonly seen after an infection or even after a vaccination.

We spend one hour with each of our patients which gives us time to deeply explore your

complex and detailed history to help find a solution.