Reaction time important in falls prevention: research
James Richardson, M.D.
Whether older adults who lose their balance can recover it and avoid falling depends not only on their lower limb strength and perception of where their limbs are but also on their complex and simple reaction times, or “brain speed,” according to results of new research published in the January edition of the American Journal of Physical Medicine & Rehabilitation.
James Richardson, M.D., a professor of physical medicine and rehabilitation at the University of Michigan Comprehensive Musculoskeletal Center, hopes his research ultimately will help prevent older adults from being seriously injured, disabled or killed from accidental falls.
In the study, Richardson and colleagues measured reaction times, leg strength and perception of motion in 42 study participants (average age: 69.1 years), 26 of whom had diabetic neuropathy and 16 who did not. They then looked to see how well those measures predicted one-legged balance time; the ability of a person to control his or her step width when walking on a hazardous, uneven surface in the research lab; and major fall-related injuries over the next 12 months.
Those participants with diabetic peripheral neuropathy who had good reaction times were able to balance on one leg for a longer period of time than those whose brains worked more slowly. The complex and simple reaction times also were the only predictors of good control of step width on the uneven surface.
In addition, the study found that reaction times appeared to identify those who sustained major fall-related injuries during the one-year follow up. Leg strength and motion perception had no influence on step width control on the hazardous surface, nor did they appear to predict major injury, the researchers said.
“It makes perfect sense that brains fast enough to have good complex reaction time accuracy were also fast enough to quickly pay attention to the perturbation while walking, inhibit the step that was planned and quickly execute a safer alternative,” Richardson said. “The faster your brain can oscillate between various external stimuli, or events, and your own internal thinking clutter, the better off you are. When an elderly person falls, it seems likely that their brain is not keeping up with what is happening and so it is not able to quickly, and selectively, attend to a particular stimulus, such as hitting a curb.”