Unlike narcolepsy type 1 which is well characterized with established markers, little is known regarding the diagnosis, prognosis, and appropriate management of the narcoleptic borderland (NBL) disorders, and controversy among experts remains about how common these disorders are. Claudio Bassetti, MD, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland, discusses SPHYNCS (Swiss Primary Hypersomnolence and Narcolepsy Cohort Study; NCT04330963), a multicenter cohort study aiming to address unanswered questions relating to NBL. Patients with excessive daytime sleepiness (EDS) and healthy controls will be enrolled to discover and validate makers for the characterization of NBL. Clinical and electrophysiological data will be collected through questionnaires, polysomnography, sleep latency tests, maintenance of wakefulness tests, actigraphy, and wearable devices. Blood, cerebrospinal fluid, and stool will be assessed for potential markers. The study began enrollment in 2020 and participants will be followed for 36 months. This interview took place during the XXV World Congress of Neurology.