Functional changes in the sleep-wake cycle after experimental traumatic brain injury

Abstract

Background. Chronic disturbance of the sleep-wake cycle is a frequent consequence of traumatic brain injury (TBI) with an unknown pathogenesis. Unavailability of intravital histological analysis of affected brain structures and the polymorphism of TBI complicate systematic study of posttraumatic disorders. Most of current research focuses on acute changes in brain cell activity following TBI. The issue of long-term TBI consequences is still relevant. Sleep disorders typical for the post-traumatic period considerably affect the cognitive function and cause secondary functional changes that lead to impaired working ability. In addition, TBI decreases the patients’ quality of life. Thus, the aim of the study was to evaluate disorders of the sleep-wake cycle during several weeks after TBI in rats using electroencephalographic analysis.
Methods. The polysomnography study detected electrophysiological changes at 1, 7, and 28 days after trauma.
Results. A delayed (28 days) impact of TBI on indexes of the sleep-wake cycle included an increased sleep duration due to longer sleep periods in the dark time of day, during the hours of rat active waking with a corresponding decrease in the sleep fragmentation index.
Conclusion. The identified nature of post-TBI sleep disorders provides better understanding of adequate therapy aimed at normalizing the sleep-wake cycle, which will help reduce the development of post-traumatic asthenia.