Diagnosing narcolepsy in the active duty military population

Narcolepsy type I and type II are central hypersomnias characterized by excessive daytime sleepiness and nocturnal sleep disruptions. These rare disorders make the diagnosis complex, as multiple sleep disorders are known to cause false-positive results on testing. There is a high incidence of sleep disorders in the military, and the diagnosis of narcolepsy can have serious career implications. This study looked to assess for the presence of confounding disorders in patients previously diagnosed with narcolepsy.

We conducted a retrospective analysis of patients aged 18-65 previously diagnosed with narcolepsy at an outside facility, referred for repeat evaluation at the Wilford Hall Sleep Disorders Center. Previous test results from the time of original diagnosis were reviewed if available and compared with repeat evaluation which included actigraphy, in-laboratory polysomnography, and multiple sleep latency testing.

Of the 23 patients, 2 (9%) retained a diagnosis of narcolepsy after repeat testing. Ten patients (43%) had insufficient sleep syndrome, five (22%) had significant circadian rhythm sleep-wake disorders, and nine (39%) patients were diagnosed with mild obstructive sleep apnea (OSA). Four of the nine patients with OSA (44%) had supine predominant OSA.

Diagnostic testing for narcolepsy may be influenced by the presence of comorbid sleep disorders including sleep-disordered breathing, insufficient sleep duration, and circadian misalignment which are common in active military personnel. This study emphasizes the importance of excluding these comorbid diagnoses in this population.