The majority of patients who experience a concussion recover fully within three months. However, a new study suggests there may be some gender differences when it comes to this form of mild traumatic brain injury. Following a concussion, women are more likely to have trouble with their short-term memories than men.

For a minority of patients — 10 to 15 percent — a concussion will affect their mental function and quality of life. Beyond the usual three months healing time, these affected patients will continue to experience problems, including headache, sleep troubles, loss of balance, memory impairments, tiredness, and even mood disorders.

By a ratio of two to one, “more women than men seek medical attention due to persistent symptoms,” Dr. Chi-Jen Chen, Department of Diagnostic Radiology and Brain and Consciousness Research Center at Taipei Medical University Shuang-Ho Hospital, said in a press release. “We started to wonder whether there might be differences in mild traumatic brain injury outcomes between men and women.”

Chen decided to investigate gender differences and their impact on healing from a concussion through a functional magnetic resonance imaging (fMRI) study. He and his colleagues studied 30 patients with concussion and 30 control patients. Both groups contained an equal number of men and women. The researchers examined patients with fMRI within a month after injury and then followed-up with a second fMRI exam at six weeks after the first scan. (This form of brain scan allows scientists to analyze brain activation patterns.) All participants also underwent neuropsychological tests, including a digit span test and continuous performance test.

Digit span is a short-term memory test. It measures how many numbers in a sequence you can remember. A continuous performance test measures your sustained and selective attention and impulsivity.

Female participants’ total digit span scores were lower in the concussion group compared to the control group. In the initial fMRI test, increased activation in working memory brain circuits was found in the male concussion group when compared with their same sex control group, while decreased activation in working memory brain circuits was found in the female concussion group. At the six-week follow-up test, the female concussion group still showed decreased activity, whereas the male concussion group had returned to normal brain activity patterns.

The results suggest the men had healed while the women had ongoing problems with their memories. Though Chen cautions this is just a preliminary study, he suggests doctors be particularly careful when treating female patients with concussion.

Source: Chen CJ, Hsu HL, Yen-Ting D, et al. Sex Differences in Working Memory after Mild Traumatic Brain Injury: A Functional MR Imaging study. Radiology. 2015.