Post-traumatic hypersomnia is excessive sleepiness that occurs after a traumatic brain injury (TBI), and that is not directly related to loss of consciousness. Hypersomnia after a TBI is common, but the exact causes of it are unclear.
A recent case study of a young woman who had suffered a TBI after a car accident provided some insight into potential causes of hypersomnia. The woman had hypersomnia, sleeping an average of 18 hours a day. She also had difficulty concentrating, and showed signs of apathy She had no personal or family history of illness or substance abuse; and her blood, toxicology and endocrine test results were in normal range. An MRI scan, however, showed damage at the left temporal lobe, and no additional damage to other areas of the brain.
The researchers suggest that damage to the left temporal lobe may have had a direct relationship with the patient's hypersomnia. It may be helpful for clinicians to consider the injured area when assessing and diagnosing hypersomnia.
Farisse J, Guedj E, Richieri R, et al. Left temporopolar impairment in a case of posttraumatic hypersomnia. Journal of Head Trauma Rehabilitation. (December 2013).