“Good Vibrations” Sharpen Sense of Balance Among Elderly


Having the Earth move under your feet can be a very good thing, especially if your sense of balance has begun to wane.

This seemingly contradictory news comes out of recent research by James Collins, a biomedical engineer at Boston University whose investigations into how the human body works often begin with “thinking-outside-the-box” approaches that produce novel results. In their report in the October 4 issue of the British medical journal The Lancet, Collins and colleagues from Harvard Medical School and Afferent Corporation, a Providence, R.I.-based medical device firm, describe results that show that imperceptible vibrations to the soles of the human foot sharpen the body’s ability to maintain balance.

This “good vibrations” finding not only upends the traditional view that vibration or other mechanical “noise” is disruptive to systems that control the way the body works, it also offers a possible solution to a major public health problem for people over the age of 65: injury or death from accidental falls. The reason for this optimism? The sole-based vibrations improved balance control most markedly among the 70-somethings who participated in the study.

Diabetes, stroke, and failing eyesight form a short list of the many factors that can adversely affect balance in individuals over the age of 65. Whatever the cause, for an elderly person a feeling of imbalance often leads to an accidental fall. Unintended falls, in fact, are the leading cause of nonfatal injury in persons 65 or older. Such accidents also are the leading cause of mortality in this age group, accounting for slightly more than 33 percent of the deaths among elderly Americans in 2000, according to the Centers for Disease Control and Prevention (CDC).

Because impaired balance often decreases a person’s ability to function independently, its psychological cost can be high. The monetary costs are too. In 1994, the CDC’s National Center for Injury Prevention and Control estimated the cost of fall-related injuries among elderly people in the United States to be $20.2 billion. By 2020, that figure could reach $34.2 billion.

Collins’s research into the biomechanics of this critical biological system aimed to determine whether the degree of back-and-forth and side-to-side swaying that occurs when a person stands quietly could be reduced if that person’s sensory and motor functions were enhanced by mechanical stimulation of the somatosensory system. This system, which includes the skin and sensory organs other than eyes and ears, gives continual feedback to the brain and nervous system on how the body is positioned in relation to its immediate environment.

For the study, the researchers focused on stimulating touch-sensitive nerves present in the soles of the feet. The team had 27 study participants stand on gel slabs that delivered imperceptible vibrations to their soles. Sway was measured with and without the vibrations. The results among the 15 young participants (mean age of 23) showed sole-based vibrations reduced sway in seven of eight parameters measured by the researchers. In the 12 elderly participants, the vibrations reduced sway in all eight measures.

Researchers speculate that the use of “noise”-based devices, such as vibrating shoe insoles, could prove beneficial to aging individuals whose sense of balance has begun to lessen.

Afferent Corporation, established in 2000, focuses on developing medical devices that can be used to treat chronic neurological dysfunctions, such as those caused by stroke, diabetic neuropathy, or aging. Its patented devices include those developed in conjunction with researchers at Boston University.

The Biomedical Engineering Department, established in 1966 in Boston University’s College of Engineering, applies engineering, computational, and analytical techniques to biological systems from the nanoscale level of DNA to the macroscopic level of organ systems. Boston University, with an enrollment of more than 29,000 in its 17 schools and colleges, is the fourth-largest independent university in the United States.