Medically reviewed by
Dacelin St Martin, MD
Triple board-certified in Sleep Medicine,
Internal Medicine, and Pediatrics.
The Pathophysiology Of Head Trauma | Common Sleep Disturbances Associated With Head Traumas | Neurobiology Of Sleep | What’s The Link Between Head Trauma And Sleep? | Direct Factors | Indirect Factors
Sleeping problems, like insomnia and hypersomnia, are common complaints in brain trauma victims. But how can head trauma result in chronic sleep disturbances?
Brain injuries are known to cause changes in mood, memory, and learning abilities, in addition to cognitive and emotional impairment.
Researchers have also studied the direct and indirect association between head injuries and sleep difficulties.
Severe trauma to the head can disrupt the glymphatic brain system’s functions, resulting in the toxic buildup of amyloid-ꞵ and T-protein and, consequently, hypersomnia.
Moreover, a severe traumatic head injury can decrease the release of wake-promoting neurotransmitters, such as hypocretin and histamine, resulting in increased sleepiness or narcolepsy.
Conversely, an injury to a different part of the brain can stimulate the release of glutamate, which causes difficulty in initiating or maintaining sleep, known as insomnia.
Fatigue, depression, anxiety, prescribed medications, genetics, and pain are other factors that can indirectly contribute to sleeping problems following head trauma.
Continue reading to learn more about common sleep disturbances following head trauma and how a traumatic brain injury can disturb your sleeping patterns.
The Pathophysiology Of Head Trauma
A concussion or head trauma can disrupt the brain’s normal functioning and result in what is known as a traumatic brain injury (TBI).
A brain injury can happen due to the sudden acceleration, deceleration, or rotation of the head during a motor vehicle accident, falling, contact sports, assaults, and explosions.
A blow, bump, or jolt to the head can damage its internal tissues and blood vessels, leading to bruising, internal bleeding, or brain swelling.
Alterations in the normal brain functions after head trauma may manifest as:
- Amnesia (loss of memory)
- Altered state of consciousness
- Neurological deficits (Muscle weakness, loss of vision, change in speech)
- Change in sleep patterns
The link between head injury and sleep difficulties has not been studied extensively. However, difficulty initiating and maintaining sleep is a common complaint in patients with a traumatic brain injury.
Common Sleep Disturbances Associated With Head Traumas
Despite their high prevalence, sleep disorders remain an under-recognized consequence of a brain injury.
Around 46 percent of patients suffer some form of sleep disorder following a TBI, including: 
- Insomnia: Another common sleep disorder that can make it hard to fall asleep, hard to stay asleep, or cause you to wake up too early.
- Post-Traumatic Hypersomnia: Excessive daytime sleepiness or prolonged nighttime sleep.
- Narcolepsy: A chronic sleep disorder characterized by increased daytime drowsiness and sudden need for sleep. People with narcolepsy have difficulty staying awake for an extended period.
- Sleep apnea: A common sleep-related breathing disorder characterized by frequent breathless episodes that interrupt sleep.
Severe head trauma can injure different locations in the brain, including sleep-regulating brain regions such as the hypothalamus, thalamus, amygdala, brain stem, and pineal gland. The type of sleep disorder resulting from a brain injury depends on the injury site within the brain.
Neurobiology Of Sleep
The hypothalamus in your brain is a key player in regulating sleep and wakefulness. It secretes neuropeptides called hypocretins or orexins.
Studies have shown that these neuropeptides increase wakefulness from either REM or NREM and are absent in the brains of some narcoleptic patients (patients who find it hard to stay awake).
Moreover, the hypothalamus releases histamine neurons which promote wakefulness and arousal from sleep.
Research has shown hypocretins regulate sleep and promote awakeness by activating histamine-producing neurons.
Furthermore, glutamate, another neurotransmitter in the brain, affects sleep regulation. The levels of glutamate are the highest during REM sleep or when you’re awake.
Additionally, the glymphatic system is a waste-clearing system in the brain. It’s responsible for removing proteins, such as amyloid-ꞵ and T-protein, from the central nervous system and preventing their toxic buildup in the brain.
Slow-wave sleep, a vital sleep phase, helps clear amyloid-ꞵ and T-protein by the brain’s glymphatic system. As a result, sleep deprivation can lead to the toxic accumulation of these two proteins in the brain. Vice versa, the buildup of T-protein and amyloid-ꞵ can disrupt the slow-wave sleep phase.
What’s The Link Between Head Trauma And Sleep?
Different sleep disorders may arise following brain injury due to various direct and indirect factors.
- Injury within the Glymphatic System: A mechanical injury to the brain can disrupt the signals of the glymphatic clearance system of the brain. This injury may result in the toxic accumulation of amyloid-ꞵ and T-protein, which can cause sleep disturbances by disrupting slow-wave sleep. Consequently, a head injury can promote sleepiness because the brain needs to compensate for lost slow-wave sleep and maximize glymphatic drainage.
- Disruption of Neurotransmitters Involved in Sleep: A head trauma can cause injury in your brain’s hypothalamus, which controls the release of hypocretin and histamine, thus disrupting the sleep regulation system in your brain. Brain trauma victims were found to have decreased levels of hypocretin and histamine wake-promoting neurotransmitters, making it harder for the brain to promote wakefulness. These neuropathological changes can explain the prevalence of hypersomnia and narcolepsy in head trauma patients.
- Ruptured Cell Membrane: A blow to the head can rupture the cell membrane of the sleep/arousal regulation system. A ruptured cell membrane will release glutamate, which increases wakefulness and leads to sleep disturbances such as insomnia.
Other indirect factors can contribute to the development of sleep problems after a severe traumatic head injury, including:
- Fatigue: The constant feeling of tiredness or weakness, known as fatigue, is common among head trauma patients and commonly associated with sleep disturbances. Post-traumatic fatigue can be a contributing factor in causing sleep trouble after an injury to the head.
- Depression: One study showed that 63 percent of TBI patients report clinically significant symptoms of depression. Research has shown a bidirectional relationship between depression and sleeping disorders. Consequently, depression can indirectly cause sleeping problems in patients following a major head injury.
- Generalized Anxiety Disorder: Generalized anxiety disorder is common among patients after a traumatic head injury. Studies have shown that anxiety disorders can lead to sleeping difficulties, generally insomnia. Therefore, having difficulty sleeping after head trauma can be the byproduct of newly developed anxiety.
- Medication: After a severe brain injury, patients may be prescribed antidepressants, analgesics, and sedative-hypnotics. These medications can add to the sleep deficits experienced by TBI patients.
- Injury to Upper Respiratory Muscle: An accident, a fall, or a crash leading to TBI may injure the upper respiratory muscles. As a result, obstructive sleep apnea can develop after head trauma.
- Genetics: Carrying certain types of genes can make an individual vulnerable to developing or worsening sleep problems. For example, a polymorphic gene called Per3 is involved in regulating the circadian rhythm – a natural internal process regulating your sleep-wake cycle. Studies revealed that following a traumatic brain injury, only patients who did not carry the Per3 gene improved their sleep quality with time. Per3 carriers, on the other hand, had shorter sleep durations and trouble sleeping even six weeks after their injury.
- Pain: Chronic pain is a common complaint among patients after a brain injury. Constant pain can keep you up at night and prevent you from getting the adequate sleep you need.
Recognizing and managing sleep disorders in head trauma patients is vital.
Untreated sleeping problems can lead to longer hospital stays, prolonged rehabilitation periods, and more disability in patients with brain injuries.
Sleep disturbances can slow down the healing process and interfere with the ability of the patient to regain cognitive function after head trauma.
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