The International Classification of Sleep Disorders, 3rd ed, lists the criteria needed for a diagnosis idiopathic hypersomnia.For a diagnosis of idiopathic hypersomnia, the following must be met:o excessive daytime sleepiness daily for at least 3 monthso cataplexy is not presento multiple sleep latency test (MSLT) shows <2 or no sleep-onset REM periods (SOREMPs) if the rapid eye movement (REM) latency on the preceding polysomnogram (PSG) was ≤15 minuteso insufficient sleep syndrome is ruled outAnd at least one of the following:o MSLT shows a mean sleep latency of ≤8 minuteso Total 24-hour sleep time is ≥660 minutes (typically 12-14 hours) on 24-hour PSG 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)o Hypersomnolence and/or MSLT findings are not better explained by another sleep disorder, other medical or psychiatric disorders, or use of drugs or medicationAdditional supportive features can include:o Severe and prolonged sleep inertiao High sleep efficiency (>90%)o Long, unrefreshing naps (>1 hour)This episode is produced by Sleep Review. It is episode 2 of a 5-part series sponsored by Jazz Pharmaceuticals. Visit Jazzpharma.com and SleepCountsHCP.com for more information.In episode 2, listen as Sleep Review’s Sree Roy and neurologist-sleep specialist Margaret S. Blattner, MD, PhD discuss:o What are some barriers to diagnosing idiopathic hypersomnia?o Objective sleep testing is needed to diagnosis idiopathic hypersomnia. What polysomnography and multiple sleep latency test findings support a diagnosis of idiopathic hypersomnia?o What are some best practices for conducting a PSG and MSLT for a patient with suspected idiopathic hypersomnia?o What are some of the additional commonly seen supportive features of idiopathic hypersomnia?