Despite the cognitive and sleep abnormalities that occur after mild traumatic brain injury (TBI), sleeping benefits memory consolidation in patients with a history of TBI, according to a study published in Frontiers in Human Neuroscience.
The benefit of sleeping on memory consolidation in patients with TBI was equivalent to their non-TBI counterparts.
People who suffer from TBI often have symptoms of disturbed sleep in addition to other memory and cognitive problems. Because sleep is beneficial for forming new memories, sleep disruptions following TBI may exacerbate any issues with memory. The researchers wanted to explore whether the sleep disturbances that follow mild traumatic brain injury have negative effects on sleep-dependant declarative memory consolidation.
The study included 26 participants aged 18 to 22 years with a history of diagnosed TBI and 30 control participants. Each participant learned a list of word pairs in the morning or evening. Their recall was tested after 12 hours following either an interval awake or overnight sleep.
Each participant was assigned to one of four groups: TBI Sleep (n=14), TBI Wake (n=12), non-TBI Sleep (n=15), or non-TBI Wake (n=15). The researchers measured sleep physiology using polysomnography, and they assessed memory consolidation by comparing change in word-pair recall after 12 hours.
Participants with TBI showed differences in their polysomnography recordings compared with the controls. Specifically, the TBI participants spent a significantly greater time in deep, slow-wave sleep and less time in non-REM stage 1 sleep.
For both the TBI and non-TBI participants, recall was higher following sleep than following a period of being awake.
“It is interesting to note that despite having atypical or disturbed sleep architecture, people in our study had intact sleep-dependent memory consolidation. Supporting opportunities to sleep following a concussion may be an important factor in recovery from cognitive impairments,” said Rebecca Spencer, PhD, of the University of Massachusetts, Amherst. “The changes in sleep architecture we observed are in an optimal direction, that is, more rich, slow wave sleep and less light or Stage 1 sleep, is a shift in the positive direction.”