By Dr. Rosabel Young M.S., M.D.
Sleep is controlled by the brain. The brain has designated neurons in the midbrain and medulla that control sleep onset, heart rate and breathing during sleep, and arousal to end sleep. Thus, it is not surprising that when brain injury occurs, sleep disturbances can occur. We call this Central Sleep Apnea.
In Central sleep apnea, the brain is no longer able to control sleep. Sleep disorders in brain injury can vary depending on what part of the brain is damaged. With midbrain damage, as in Parkinson’s disease, alcohol dependency, and some medication side effects, REM sleep behavior disorder occurs because the Reticular Activating System does not properly shut down movement during dreams in REM sleep.
Sleep disorders after brain injury also depend on a person’s prior history. For example, with a history of obesity, diabetes, and hypertension obstructive sleep apnea can occur along with central sleep apnea. Persons with obstructive sleep apnea generally are more aware that they have a problem than those with central sleep apnea. The fact that you had a brain injury in and of itself may prevent you from becoming aware of your own symptoms.
Excessive daytime somnolence and insomnia are common symptoms, but sleep disorder after a brain injury may only become apparent if someone observes the patient while asleep. In addition to abnormal breathing at night, persons with brain injury may have jerking movements of their arms, legs, and body, or even organized movement as if they were awake, such as attempting to get out of bed while still asleep. These symptoms occur because of abnormal brain activity and may not be detected in routine sleep studies that only measure airway breathing and cutaneous oxygen.
Therefore, it is important to do a sleep study with a full electroencephalogram that records brainwave activity as well as oxygen saturation and nasal airflow which are normally measured for obstructive sleep apnea. If you are scheduled for a sleep study, be sure that it includes a full brainwave recording as well as the obstructive apnea parameters.