fMRI reveals women suffer more memory impairment following concussion

Women with concussions, or mild traumatic brain injury (MTBI), may have more impairment in working memory processes than men with MTBI, according to a study published online April 28 in Radiology.

Concussions account for a majority of all instances of brain injury, and although most people fully recover within three months, in rare cases MTBI can result in diminished cognitive and vocational capacity, as well as a reduced quality of life for affected patients. The issue of the long-term effects of concussions has drawn considerable interest recently due to high-profile cases involving both male and female athletes involved in amateur and professional sports.

Differences in the impact of concussions according to sex have yielded inconclusive results in human subjects, as traditional methods of imaging have proven ineffective at assessing the effects of MTBI on certain brain functions including working memory, according to lead author Hui-Lin Hsu, MD, and his colleagues at Taipei Medical University Shuang-Ho Hospital in Taiwan. “Conventional anatomic imaging techniques, including MRI and CT, generally fail to show focal lesions in patients with MTBI,” wrote Hsu and colleagues. “Functional MR imaging performed with blood oxygen level–dependent signals is increasingly being used in patients with MTBI.”

The Taiwanese research team set out to assess whether or not sex differences exist in working memory function for concussion patients using functional MR imaging. To do so, they performed working memory functional MRI on a total of 30 patients (a group of 15 men and another group of 15 women) suffering from MTBI, as well as two corresponding control groups without the condition. A preliminary imaging study was performed on both groups within one month of injury resulting in MTBI, as well as a follow-up study six weeks after the initial study. Digit span and continuous performance testing were performed before functional MR imaging for each patient studied.

Their results revealed that female patients with MTBI had lower digital span scores than those in the control group and showed persistent hypoactivity in working memory function after the six-week follow-up examination. Conversely, male patients with MTBI showed hyperactivity in initial functional working memory MR exams, but that hyperactivity regressed to statistically insignificant levels compared to the control group of men at six-week follow-up. “Functional MR imaging depicted sex differences in working memory functional activation,” wrote Hsu et al. “Hypoactivation with nonrecovery of activation change at follow-up studies may suggest a worse working memory outcome in female patients with MTBI.”

While the sample size was limited and confounding factors could not be ruled out, the researchers believe their findings could have a positive impact on the future assessment and treatment of both female and male patients suffering from MTBI. “These results may change the future diagnostic work-up in patients MTBI and lead to separate management strategies for patients of different sexes,” the authors wrote. “Furthermore, multimodality imaging studies … may be helpful in understanding the underlying pathophysiology and causes of sex differences in MTBI.”