Particular Case of Traumatic Brain Injuries
Sleep disorders are one of the main symptoms of minor brain
trauma in children and young adults. One study found that
55 percent of patients reported daytime sleepiness one
month after a traumatic brain injury (TBI). That compares to
41 percent of people who experienced trauma without a brain
injury and 3 percent of a trauma-free control group.
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One year later, 27 percent of the TBI patients continued to
report sleepiness. The study divided groups into patients
with mild, moderate and severe brain trauma. In people with
severe brain trauma, 90 percent of respondents could not
discuss their own sleep patterns (“self-report”) because of
cognitive difficulties.
Researchers hypothesize that sleepiness following a TBI
is caused by an injury to the posterolateral hypothalamus,
which decreases levels of the excitatory hypothalamic
neuropeptide hypocretin-1 (orexin). Orexin is an alerting
neurotransmitter made in the lateral hypothalamus.
Because orexin is broadly distributed both to the cortex
and to the brainstem, it’s easy to see how the forces of a TBI
could disrupt its production. One study found deficient levels
of hypocretin in 95 percent of patients who experienced acute
moderate to severe TBIs.
Studies have shown that long-term outcomes from severe
brain injuries can be compromised when patients experience
sleep disorders. Once you eliminate sleep disorders,
cognitive deficits might improve or disappear.