Lena Ting, from Emory University, and colleagues explored how brain and muscle activity during balance recovery change due to aging and Parkinson's.
Previously, Ting's research group revealed that when they pulled a rug out from under young adults to trigger balance recovery, these individuals experienced an immediate involuntary brainstem and muscle response followed by a second wave of activity in the brain and muscle in more difficult balance disturbances. In this new study on older adults with and without Parkinson's, published in eNeuro, the researchers discovered that these populations have larger brain responses and more muscle signals even when balance disturbances are small. Says Ting, "Balance recovery takes more energy and engagement from the brain in these populations. We found that, when people require more brain activity to balance, they have less robust ability to recover their balance." The researchers also discovered that when older people activated a muscle to recover their balance, the opposing muscles would stiffen up. The degree to which people stiffened their muscles was also linked to worse balance performance.
The researchers emphasize that their technical approach could have clinical implications as a more precise way to gauge whether someone is at risk for poor balance recovery. Ting notes that they still have more work to do in optimizing the approach, but adds, "We may be able to determine whether someone has increased brain activity simply by assessing muscle activity after pulling a rug out from under you." This method could help identify at-risk people before they fall, who may benefit from balance training and exercise.
