Other names: Excessive Daytime Sleepiness; Hypersomnia; Idiopathic Hypersomnolence; IH; Somnolence
Idiopathic hypersomnia is a debilitating neurologic sleep disorder characterized by chronic excessive daytime sleepiness, making it difficult to stay awake and alert during the day.
People with idiopathic hypersomnia can sleep for adequate amounts of time each night but still feel excessively sleepy during the day. They may also experience severe sleep inertia or sleep drunkenness (difficulty waking, and grogginess and disorientation upon awakening).
The cause of idiopathic hypersomnia is not known but may be related to the presence of a substance that interacts with gamma-aminobutyric acid (GABA) in the cerebrospinal fluid, thereby enhancing the sleep promoting effects of GABA. Other possible causes of idiopathic hypersomnia include autonomic nervous system dysfunction, circadian system dysregulation, and dysfunction of energy metabolism.
Diagnosing idiopathic hypersomnia involves trying to establish a cause, and to rule out other conditions. Patients may be asked to rate their sleepiness on the Epworth Sleepiness Scale, keep a sleep diary, take a polysomnogram test, and a multiple sleep latency test to determine the cause of their sleepiness.
Treatments for idiopathic hypersomnia are aimed at easing symptoms. Xywav (calcium, magnesium, potassium, and sodium oxybates) is the first and only FDA-approved treatment for idiopathic hypersomnia. Off-label treatments include wakefulness-promoting agents (modafinil and armodafinil) and psychostimulants (amphetamines and methylphenidate).
