People who experience even a mild traumatic brain injury may suffer from brain damage and memory problems, a new study has found.

According to UK scientists, most studies in this area have focused on severe traumatic brain injuries, so they set out to investigate the effects of mild injuries.

"We studied patients who had suffered clinically mild injuries often from common accidents such as falling from a bicycle, or slow speed car accidents. This finding is especially important, as 90% of all traumatic brain injuries are mild to moderate," commented the study's author, Dr Andrew Blamire, of Newcastle University.

A traumatic brain injury can be classified as mild if loss of consciousness and/or confusion and disorientation lasts less than 30 minutes.

The scientists monitored 44 people who had suffered a mild traumatic brain injury and nine people who had suffered a moderate injury. These were then compared to 33 people with no brain injuries.

All of the participants underwent tests to assess their thinking and memory skills and they also had brain scans to detect any damage. One year later, 23 of the participants with injuries had another scan and underwent the cognitive tests again.

The study found that people who had suffered an injury had damage in the white matter of their brains, affecting how brain cells transmit messages to each other.

Furthermore, those with traumatic brain injuries scored 25% lower in a test of thinking and memory skills compared with people who had no brain injuries. This appeared to be strongly linked to the white matter damage.

One year later, those who had suffered a traumatic brain injury scored the same on the thinking and memory tests as those without brain injuries, however their brains still showed signs of damage.

"These results show that thinking skills were recovering over time. The areas of brain damage were not as widespread across the brain as previously, but focused in certain areas of the brain, which could indicate that the brain was compensating for the injuries," Dr Blamire noted.

Details of these findings are published in the journal, Neurology.