Scientists at Emory University have discovered important differences in how the brain and muscles work together to maintain balance in older adults and people with Parkinson's disease compared to younger individuals. The research team, led by Lena Ting, used a technique that simulates sudden balance loss by pulling a support surface out from under participants, similar to having a rug yanked away.
Previous work with young adults revealed a two-stage response system. Minor balance challenges triggered a rapid, automatic reaction controlled by the brainstem, which connects the brain to the spinal cord and manages many involuntary functions. More severe challenges activated a secondary response involving higher brain regions along with coordinated muscle activity.
The new study, published in the journal eNeuro, examined how this system functions differently in older populations. Researchers found that older adults, both with and without Parkinson's disease, showed significantly stronger brain responses and elevated muscle activity even when dealing with small balance disturbances. This indicates that their nervous systems must work harder to accomplish the same stabilizing task that younger people handle more effortlessly.
Ting explained that this increased effort comes with a trade off. When the brain must dedicate more resources to basic balance maintenance, the overall system becomes less capable of recovering from sudden disruptions. This paradox means that despite showing more activity, these individuals actually have reduced balance recovery ability.
The research also uncovered a problematic muscle coordination pattern. In older adults, when one muscle contracts to correct balance, the opposing muscle on the other side of the joint often simultaneously tightens rather than relaxing. This phenomenon, called co-contraction, creates stiffness that works against smooth, efficient movement. The added rigidity was directly correlated with worse balance performance during testing.
These findings could have practical applications for fall prevention. The research team suggests their experimental approach might eventually become a diagnostic tool to identify people at higher risk of balance problems. Rather than requiring expensive brain imaging equipment, clinicians might assess risk by measuring muscle activity patterns during controlled balance tests.
If this method can be refined and validated, it could enable earlier intervention for at risk individuals. People identified as having compromised balance systems could begin targeted exercise and balance training programs before experiencing a serious fall, potentially preventing injuries and maintaining independence longer.