Sleep helps memory consolidation even in individuals who sustain mild traumatic brain injury (TBI), also known as concussion, new research has found.

After a concussion, a person can be left with disturbed sleep, memory deficits and other cognitive problems for years.

"It is interesting to note that despite having atypical or disturbed sleep architecture, people in our study had intact sleep-dependent memory consolidation," said lead researcher Rebecca Spencer from University of Massachusetts Amherst in the US.

"Supporting opportunities to sleep following a concussion may be an important factor in recovery from cognitive impairments," Spencer noted.

The researchers found that individuals who had sustained a mild TBI more than a year earlier had greater recall in a word memorisation task after they had slept than when tested after an equal period awake.

Specifically, data from participants who had a concussion more than one year before had differences in sleep as measured by polysomnography, a montage of recordings used to stage sleep.

They spent a significantly greater part of the night in deep, slow-wave sleep, a sleep stage where memories are replayed and consolidated to long-term storage.

Their memory and recall ability was not significantly different than the study subjects who had no TBI.

"Overall, sleep composition is altered following TBI but such deficits do not yield insufficiencies in sleep-dependent memory consolidation," the study noted.

For this work, the researchers recruited 26 young adults 18 to 22 years old with a history of diagnosed TBI an average three to four years earlier from various causes, and 30 others with no history of brain injury.

The study appeared in online edition of the journal Frontier in Human Neuroscience.