The aged: The fastest growing population in Canada — November 2010
A question of balance and touch
Three uOttawa researchers have found an interesting niche in the study of the effects of aging on mobility.
The three researchers, whose laboratories are at the Élisabeth Bruyère Research Institute in Ottawa’s Lowertown (as part of a larger centre which serves seniors) and at the 200 Lees campus, are part of a group that began working together on a semi-formal basis in 2004, with a broad mandate that included investigating sociocultural and policy factors as well as physical factors affecting the health and quality of life of older adults. Over time, the group evolved, leaving a core unit of five researchers with a shared focus on the effects of aging on mobility. Though aging is often associated with conditions such as Alzheimer’s and a decline in cognitive abilities, the unit is more interested in the impact of aging on motor control and the ability to use sensory information to produce coordi-nated actions. “Our work looks at the effects of ‘normal’ aging on a person’s capacities. We’re not necessarily looking at pathology. We look at natural decline,” says Bilodeau.
Bilodeau believes that the unit’s work can have an impact on prevention. With the relatively healthy baby boomers moving towards old age, “we have to be interested in the impact of normal aging to better understand how the body adapts to these changes.” This allows us to better anticipate and address issues relating to aging, such as why certain people are prone to falling.
While the work of the three researchers does overlap—and in conversation, they are happy to pick up on each other’s thoughts, each researcher has his own projects.
Bilodeau tends to look at the issue of balance. For example, he has studied the effect of a bout of exercise leading to muscle fatigue on seniors’ sense of balance. He notes that seniors are more susceptible to fatigue when performing postural tasks such as standing up or tasks requiring fine dexterity.
As for Tremblay, his focus has been on hand function. Using what is called a psychophysical approach, he examines tactile perceptual abilities in seniors, or what they can feel with their fingertips. For example, he found that, from the ages of 60 to 75, there is a substantial decline in seniors’ ability to recognize fine shapes or textures by touch. In fact, they often require stimuli two to four times stronger than young adults do to achieve the same level of recognition. His research has also shown that the degree of tactile loss in the fingertips with age is strongly associated with impaired manual dexterity, a discovery other researchers have picked up on.
Tremblay also uses transcranial magnetic stimulation (TMS) to explore the regions of the brain responsible for motor functions in a non-invasive manner. These investigations have shown, for instance, that motor response is greatly enhanced when participants are actively touching objects with their fingers. In seniors, this effect appears to be highly dependent on how acute their tactile sense is, as lower ability to distinguish shapes leads to decreased motor response. Such findings could have clear implications for the re-education of hand function after a stroke, for example.
Lajoie has been looking at the issues of balance, the risk of falling and locomotion. For example, he tested 150 subjects’ ability to hold a posture. He believes it is possible to train seniors to be less susceptible to falling by helping them become more aware of their physical environment.
In his work, Lajoie relies on techniques such as biofeedback and virtual reality as well as blind navigation. Through blind navigation, Lajoie can study how seniors move in space without vision, including how they compensate for the loss of vision, as well as how they respond to “attention demands,” or the cognitive resources needed to perform a task, such as standing up.
So what’s next for the group? Tremblay suggests that one benefit of their research might be more attention to seniors’ footwear. For example, perhaps seniors should pass up overly absorbent soles in favour of shoes that stimulate the foot (the same approach can be applied to special gloves). He also believes in retraining strategies for seniors, relying on their central nervous system’s adaptability to compensate for any decline. Bilodeau wants to look at the effects of both normal aging and events like a stroke, using exercise and tools such as virtual reality to expand seniors’ capabilities. But as Lajoie notes, “we still have a lot of evaluating to do. The primary goal is prevention