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Retired NFL players have slightly higher rate of cognitive impairment and depression

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Football has always been a dangerous game. Now researchers are learning more about the long-term effects professional players may be experiencing from career-related head injuries.

A recent small study compared the cognitive skills and brain features of a group of retired NFL players and healthy individuals of similar ages.

The study found that the rate of dementia among the NFL players was approximately the same as the rate in the general population. However, they had a higher rate of cognitive impairment than the general population.

The ones with cognitive impairment also had significant differences in the white matter and blood flow of their brains compared to the healthy individuals.

This research adds to what scientists have been learning about the risks of repeated head trauma and offers new ways to identify possible cognitive problems through brain scans.

"Protect your head."

The study, led by John Hart, Jr, MD, of the Center for BrainHealth at The University of Texas at Dallas, aimed to see whether aging NFL players had different rates of cognitive impairment or depression than the general population.

The researchers assessed neurological symptoms in 34 retired NFL players and then compared the brain images of 26 of these players with brain images of 26 healthy individuals. Eight players did not have their brains imaged due to claustrophobia.

The retired players had been in the NFL anywhere from 2 to 15 years, and their ages ranged overall from 41 to 79, with an average age of 61 for the group. Eighteen had played offense, 16 played defense.

Most of the players (29 of them) exercised at least three times a week or more, and as a group they had an average of 4.5 operations in their lifetime that required general anesthesia.

All but two of the players had experienced at least one concussion, with reports ranging from one concussion to 13 in their lifetimes. The average was four concussions. Some players were out only a few seconds, and some had been unconscious for several hours.

In addition to looking at the participants' cognitive skills and symptoms of depression, the researchers studied brain images for the blood flow and amount of white matter in the brain.

Twenty of the 34 NFL players had normal cognitive skills for their age. Two had dementia, four had a cognitive deficiency, and eight had mild cognitive impairment. Eight were depressed.

While the rate of dementia in this group is about average compared to the general population, the rate of mild cognitive impairment in this group was higher than average. The depression rate (24 percent in this small group) was also higher than average for this age group (usually about 15 percent).

Past studies have shown higher rates of dementia among older retired NFL players. The researchers said the smaller percentage might have been because the participants had volunteered to participate (instead of being randomly selected) and/or because they had a higher average IQ than seen in past studies.

The players in this study who had a history of concussion showed poorer memory and other cognitive skills, including slower motor skills, suggesting that concussion might contribute to brain problems that later lead to cognitive impairment.

However, the researchers did not have data on these players' cognitive skills before their concussions, and the sample size of the study was very small, so they could not draw broad conclusions about this correlation between concussion and cognitive impairment.

When the researchers looked at the brains of those who underwent magnetic resonance imaging (MRI), they found notable differences in the number of abnormalities in the white matter of players with cognitive impairment and depression, compared to the white matter in brains of healthy comparison individuals.

They also saw differences in these cognitively impaired and depressed players' brains in terms of the blood flow. The areas related to memory, naming and word finding had increased or decreased blood flow compared to what was seen in the healthy individuals' brains, depending on the part of the brain they looked at.

The healthy participants for comparison had been recruited from another study on aging. They were similar to the football players in terms of age, educational background and estimated IQ.

The individuals in the healthy comparison group had no history of psychiatric or cognitive problems, had not had a concussion (to their knowledge) and had not played college or professional football.

In a commentary about this study, published in the same journal, Ramon Diaz-Arrastia, MD, PhD, and Daniel Perl, MD, wrote that the "the main value of the study is that it potentially identifies a novel target for measuring disease progression and developing therapies."

In other words, learning about the differences in white matter and blood flow on the MRI scans may help healthcare professionals identify possible cognitive problems earlier on for individuals. So far, differences in white matter have not been considered typical for chronic traumatic encephalopathy, in which a head sustains repeated injury.

Another value of the study is that it shows what kind of shift is needed in the culture of the NFL, said Daniel Clearfield, DO, a sports medicine doctor at the Ben Hogan Bone & Joint Institute in Fort Worth, Texas, and a dailyRx expert.

"This study helps further strengthen the case for the NFL (and other sporting organizations) to have a better reformation of how the game is played, to avoid multiple head injuries and lessen the chances of developing CTE and other [disease symptoms from] multiple concussions," Dr. Clearfield said.

The study was published January 6 in JAMA Neurology. The research was funded by the BrainHealth Institute for Athletes at The University of Texas at Dallas and by a grant from the National Institute on Aging. No conflicts of interest were reported.

Reviewed by: 
Review Date: 
January 6, 2013
Last Updated:
August 14, 2013