Why People Fall

Researchers from the University of Michigan have delved into the question of why people—especially older individuals—fall. They now believe that the critical window of time between when the brain senses a fall and the muscles respond may help explain these falls.

The researchers, from the U-M School of Kinesiology, developed a novel way of looking at the electrical response in the brain before and during a fall by using an electroencephalogram (EEG). Their findings showed that many areas of the brain sense and respond to a fall, but that happens well before the muscles react. Lead researcher Daniel Ferris likened the study method to recording an orchestra with many microphones and then teasing out the sounds of specific instruments. In the study, researchers measured electrical activity in different regions of the brain.

“We’re using an EEG in a way others don’t, to look at what’s going on inside the brain, ” said Ferris, a professor in kinesiology, in the August 14, 2013 news release. “We were able to determine what parts of the brain first identify when you are losing your balance during walking.”

During the study, healthy young subjects with electrodes attached to their scalps walked on a balance beam mounted to a treadmill. When participants lost their balance and went off the beam, they simply continued walking on the moving treadmill, thus avoiding injury. The team then used a method called independent components analysis to separate and visualize the electrical activity in different parts of the brain. They found that people sense the start of a fall much better with both feet on the ground. Two grounded feet make it easier to determine where the ground is relative to the body.

The researchers were surprised that so many different parts of the brain activate during a fall. They also did not expect the brain to recognize a loss of balance as early as it does. Future studies comparing the elderly with younger subjects could determine if the elderly sense falls too late, in which case, pharmaceuticals might help them regain their balance. If it’s a simple motor problem such as muscles not responding properly, strengthening exercises could help.

Dr. Ferris told OTW, “New mobile EEG technologies are making it possible to monitor people during a wide range of tasks. We can get information out of the EEG that includes when they sense they are going to fall. In the near future, it may be possible to determine if elderly individuals that fall have a problem with sensing they are losing their balance or is their problem limited to being strong and powerful enough to correct their balance.”

Regarding future research, Dr. Ferris commented, “We have funding from the U.S. Army Research Laboratory that is designed to push the technology into more easily accessible and portable formats so that real-time brain monitoring can occur in activities of daily living.”