Mentally Overestimating Motor Tasks May Cause Cognitive Fatigue in MS

People with multiple sclerosis (MS) tend to mentally overestimate the time required to complete a short walking activity, causing cognitive fatigue that may affect their quality of life, a study reports.

The connection between cognitive fatigue and imagined motor exercises may offer a potential therapeutic approach to improve motor function and quality of life in MS patients, the researchers said.

Motor imagery (MI) is the process of mentally simulating or imagining a motor activity like walking, without physically doing the activity. Previous research suggests that the brain functions required to imagine performing a motor activity are similar to actually doing it. In healthy adults, these real and imagined activities are believed to have a temporal coupling — meaning, a similar duration between actual and mental movements.

In MS patients, however, a degree of incongruence is observed between imagined and actual motor tasks, resulting from abnormal brain activity that may indicate extra mental exertion to perform physical tasks.

MI therapy has been shown to improve walking and limit fatigue in people with MS.

“Investigating the relationship between fatigue and MI performances in [patients with] MS could be key to shedding new light on the motor representation of [MS patients] and providing insights into new rehabilitative treatments,” the investigators wrote.