White matter hyperintensities are associated with neuropathological changes, according to a new study which compared antemortem brain MRI scans of deceased athletes with postmortem changes in their brains. These athletes had played contact sports and had been exposed to repetitive head impacts.

The study group involved 67 football players (professional / semi professional) and 8 non-football athletes who played contact sports like boxing and/or military veterans. All of them had donated their brains after their death for the purpose of research into the long-term effects of repetitive head impacts. They had undergone fluid attenuated inversion recovery (FLAIR) MRI scans at 62 (mean) years of age. There was no brain tumor, large vessel infarcts, hemorrhage, and/or encephalomalacia. The average age at the time of death was 67 years. White matter hyperintensities (WMH) on FLAIR MRI scans, from their medical records, were measured using log-transformed values for total lesion volume (TLV).

Around 71% (n = 53) were found to have postmortem evidence of chronic traumatic encephalopathy (CTE), which is a neurodegenerative disease occurring due to repetitive head impacts. The most common indication for MRI was found to be dementia in 64%, which was also verified by their family members.

Examination of brain MRI scans revealed that with every unit change in the volume of white matter hyperintensities, the probability of having more severe small vessel disease - white matter rarefaction (OR 2.32) and arteriolosclerosis (OR 2.38) - doubled along with a three-fold increase in accumulation of tau protein in frontal lobe (OR=3.03). Those who had longer years of playing football or had more head impacts during their careers had higher amounts of white matter hyperintensities on MRI.

The larger amounts of white matter hyperintensities showed a correlation with difficulty in performing daily tasks as evident by higher scores on the Cognitive Difficulties Scale (CDS) and Functional Activities Questionnaire (FAQ), which were filled by caregivers of the brain donors.

This study published in the journal Neurology suggests that the long-term impact of repetitive head impacts in athletes who play contact sports can be assessed by quantifying the white matter hyperintensities on MRI scans when the athlete is still living. The longer the athlete played the sport, greater was the number of white matter hyperintensities. Hence, routine brain scans can reliably detect this neuropathological evidence of repetitive trauma to the head, particularly in athletes who play contact sports.

Reference

1. Uretsky M, et al. Association between antemortem FLAIR white matter hyperintensities and neuropathology in brain donors exposed to repetitive head impacts. Neurology. 2021 Nov 24;10.1212/WNL.0000000000013012. doi: 10.1212/WNL.0000000000013012.