Review medications before testing, because REM suppression can invalidate the study and obscure the diagnosis. A nocturnal polysomnogram followed by a daytime sleep latency test is the standard objective pathway when narcolepsy is suspected.

Polysomnography should usually be followed by a multiple sleep latency test when narcolepsy is suspected; Sleep-onset REM episodes support the diagnosis; SSRIs can suppress REM sleep and distort the study; Medication tapering should be considered when clinically feasible; Objective testing helps separate narcolepsy from other causes of daytime sleepiness