Allowing ad libitum sleep during overnight polysomnography affects Multiple Sleep Latency Test results in patients being assessed for hypersomnolence.

Study Objectives: The Multiple Sleep Latency Test (MSLT) is a key diagnostic component in the diagnosis of central disorders of hypersomnolence. Due to time constraints, it is common practice to wake patients at a standard time from overnight polysomnography (PSG) prior to the MSLT. This has the potential to influence MSLT results due to sleep deprivation.