An investigation into the link between concussions with loss of consciousness history and brain changes in retired NFL players revealed these types of injuries can lead to impaired memory performance later in life.

A team of researchers looked at the relationship between memory performance with hippocampal volume and concussion history, the JAMA Network Journals reported.

The study included 28 former athletes, eight of whom were diagnosed with mild cognitive impairment (MCI). The researchers also looked at 21 cognitively healthy control group participants with no history of concussion and six control patients with MCI but no history of concussion.

The study revealed athletes with a history of concussions but without MCI had normal scores on a verbal memory test, but their scores were generally lower than subjects who had never suffered a concussion.  Athletes with a concussion history and MCI performed worse than both the healthy controls and athletes without MCI. There was no observed difference in scores between control participants with MCI and athletes with MCI.

Athletes who did not have a history of concussion with loss of consciousness had similar hippocampal values to the control participants of all ages, but older former athletes who suffered at least one major concussion has smaller hippocampal volumes.

"Our findings suggest that a remote history of concussion with loss of consciousness is associated with both later-in-life decreases in hippocampal volume and memory performance in retired NFL players. ... Our findings further show that a history of G3 concussion in athletes with MCI was associated with greater hippocampal volume loss compared with control participants with MCI. Prospective longitudinal studies after a G3 concussion would add further insight to the mechanism of MCI development in these populations," the study concluded.

The findings were published in a recent edition of the journal JAMA Neurology.