• Kleine-Levin syndrome (recurrent hypersomnia), which is
seen in teens and young adults, mostly males; between
periods of hypersomnia, patients experience typical
sleeping patterns
In patients with neuromuscular disorders, such as cerebral
palsy or muscular dystrophy, daytime sleepiness also can
be a symptom of hypercarbia. Hypercarbia is caused by
restrictive lung disease, muscle weakness and difficulty
managing secretions.
More often, primary-care providers will see hypersomnia
resulting from secondary causes, such as brain injuries
(see next section) and disorders that fragment nighttime
sleep. Disorders that fragment sleep include restless leg
syndrome, sleep apnea, nocturnal seizures, and periodic limb
movement disorder.