Stroke is the number one cause of neurological disability in Canada. Each year, 50,000 Canadians have a stroke, and of those who survive, 76 per cent are left with a significant disability. Mobility impairment is the major problem faced by most people who have had a stroke, but there are few community exercise programs to maintain mobility and function after formal therapy ends. Poor cardiovascular fitness and a decrease in bone density put people who have experienced a stroke at greater risk for depression, cardiovascular disease, recurrent stroke, falls and fragility fractures. Dr. Maureen Ashe is investigating whether a community-based exercise and education program reduces these secondary complications, by improving balance, strength, bone density and overall level of fitness. While other research has looked at the short-term benefits of exercise in a clinical setting, this is the first Canadian study to examine if exercise improves health among people living in the community following a stroke, and to evaluate the cost-effectiveness of this approach in reducing falls.
Research Pillar: Clinical
Prevention of osteoporotic hip fractures: Linking novel clinical imaging tools to laboratory measures of bone strength
Osteoporotic fractures among the elderly are a growing public health burden worldwide. Osteoporotic fractures are associated with a high incidence of disease and disability, and high risk for long term institutionalization. They also add substantial costs to the healthcare system. The main factors that cause hip fracture include experiencing a fall, loss of protective mechanisms and reduced bone strength. Integrated methods and tools for improving prevention strategies are therefore crucially needed. Dr. Saija Kontulainen is utilizing state-of-the-art imaging tools to better detect individuals at high risk for osteoporotic fracture. She is investigating whether these new tools can more accurately measure bone size and structure than the most common diagnostic procedure, bone density testing. The current procedure measures the amount of mineral in bones and is not potent to predict fracture risk of an individual. Saija is determining if the new imaging tools can identify which bone properties are key factors in hip fracture. The tools could also be used to monitor the effectiveness of bone therapies involving medication, nutritional supplements and exercise.
Molecular pathways linking depression and inflammation
Clinical depression is a long-lasting and often recurring disease, involving feelings of oppressive sadness, fatigue, guilt, loneliness, worthlessness and helplessness. These psychological symptoms cause distress and also threaten the physical health of depressed people. Recent research has shown that people suffering from clinical depression are at greater risk of developing coronary heart disease. People who become depressed after a heart attack are three to four times more likely to die from cardiac disease. But it is unclear why this occurs. Dr. Nicolas Rohleder is studying whether the mechanisms that normally control the immune system stop functioning properly in people with depression. It’s known that the immune systems of depressed people produce more inflammatory molecules, which foster atherosclerosis (narrowing of the arteries), the inflammatory condition that is the main cause of coronary heart disease. Nicolas is investigating the molecular mechanisms that link depression with inflammation, which could ultimately lead to new therapies to reduce the risk of chronic heart disease in depressed people.
Biomechanics and prevention of vertebral fractures due to falls
Vertebral fractures in the spine are the most common type of fractures resulting from osteoporosis. These fractures cause back pain, impair physical function, reduce quality of life, increase mortality, and result in massive hospital and continuing care costs. After one vertebral fracture, the risk of a second vertebral fracture within 12 months increases fourfold. Most vertebral fractures result from a backwards fall. Dr. Meena Sran is conducting the first study to examine the forces that impact the spine during a typical backwards fall, and ways to reduce this load. Meena is investigating three promising techniques for preventing vertebral fractures during falls: having high risk fallers wear padded, shock-absorbing protective garments; installing floors that are less stiff; and using safe-landing techniques. The research could contribute new strategies to prevent vertebral fractures.
Renal function and cardiovascular outcomes in patients with atherosclerotic renal artery stenosis
Renal artery stenosis is the narrowing of the arteries that supply blood to the kidneys. Research on the progression of kidney and cardiovascular disease in patients with this condition is limited. Dr. Nadia Zalunardo is examining whether kidney disease progresses more quickly in people with renal artery stenosis. Nadia is also studying whether people with the condition have higher rates of mortality, cardiovascular events such as stroke, heart attack and heart failure, and vascular procedures such as amputations and bypass surgery. The research could increase understanding about whether treating cardiovascular risk factors, such as diabetes, high blood pressure and elevated cholesterol, slows the progression of kidney disease and improves outcomes in patients with renal artery stenosis. The findings could also enable nephrologists (physicians specializing in treating kidney disease) to better project the need for dialysis and improve care for patients with kidney disease.
Neuromuscular versus behavioral influences in control of postural stability in elderly women
Falls are the leading cause of injury and injury-related deaths in elderly people. Impaired muscle strength, joint movement, balance, gait, vision, hearing and cognition predispose people to fall. But efforts to predict and prevent falls based on these risk factors have met with limited success. Fabio Feldman is comparing how people with a history of falling and non-fallers control their movements. Motor and cognitive functions may decline as people age. Fabio is investigating whether a tendency to attempt movements that exceed motor capacities, due to an exaggerated perception of physical abilities, is an important cause of falls in the elderly. He is measuring motor capacity for balance, reaction time, flexibility and strength in fallers and non-fallers. The research could lead to better tools for predicting and reducing risk in elderly individuals at high risk for falls. The results could also be applied in other areas, such as assessing driving abilities of the elderly and physical rehabilitation following a stroke or injury.
Maternal decision making regarding initiating stimulant treatment for child ADHD
About three to five percent of school aged children have Attention-Deficit/Hyperactivity Disorder (ADHD). Children with ADHD have difficulty sustaining attention, uncontrollable hyperactivity and impulsive behaviour. They account for a significant number of referrals to children’s mental health services. Stimulant drugs, such as methylphenidate (Ritalin) and dextroamphetamine, generally reduce ADHD symptoms. However, 22 to 26 percent of parents who have children with ADHD decide against treatment using these medications. Research shows children with ADHD who are never medicated are at greater risk for substance abuse than those treated with medication. While some parents reject stimulant drugs in favour of behavioural therapy, which has also been demonstrated to be effective, other parents reject drug therapy in favour of less effective and possibly harmful treatments such as diet or vitamin therapies, or no treatment at all. Carla Seipp is studying how beliefs held by parents, teachers and friends about ADHD and information provided by physicians influence a mother’s decision about initiating stimulant drug treatment. The findings could help physicians and families address barriers to using these medications.
Attention and optic flow in dynamics scenes
The ease with which most people navigate their surroundings conceals an important fact: the brain works very hard to take in as much information as possible about the environment to plan and coordinate actions needed to get around. But how this occurs is not well understood. Vision is one of the most important sources of information for navigation. As people move, visual information continually changes in a process known as optic flow. This process helps inform the brain of actions needed to get to a certain destination, and how to avoid any obstacles along the way. Alzheimer’s disease is often associated with difficulties perceiving optic flow. As a result, people with Alzheimer’s are at significantly greater risk of injury from falls and car accidents. Christine Tipper aims to understand how optic flow is used for navigation by examining how we attend to the dynamic visual information encountered as we move through the environment. Her research goal is to gain insight into how the brain processes this visual information and uses it to coordinate effective actions. This understanding could help explain problems with navigation seen in people with Alzheimer’s, and may be an important step towards developing useful remediation or coping techniques.
Social effects on a linguistic mechanism in Autism Spectrum Disorders
Children and adults with one of the group of pervasive developmental disorders known as Autism Spectrum Disorders (ASD) have difficulties with language and social interaction. Language problems are especially disabling, as most activities rely on language. Katherine Yoshida is researching whether the ability to learn language is impaired in people with ASD because it is generally learned through social cues and interaction. Children, for example, may follow a parent’s eye movement to associate a word with an object. But children with ASD often do not make eye contact. Katherine is investigating whether reliance on social interaction to develop language impedes learning in people with ASD. The research could confirm that people with ASD learn language more effectively in non-social settings, and the results could be used to develop alternative learning strategies that improve communication abilities in people with ASD.
The control of visual attention by the demands of locomotion – implications for movement disorders and their clinical diagnosis
For sighted individuals, normal everyday activities such as walking down a busy street or through a crowded grocery store are based on using vision to identify not just where one is headed, but what obstacles and hazards need to be avoided as well. While this ability to visually guide our actions may appear effortless, the task requires a complex coupling between the visual and motor systems. When disease or brain injury compromises these links between the visual and motor systems it becomes acutely obvious how much the brain is doing behind the scenes to promote normal motor behaviour. Most research on visual attention and its role in normal cognitive function has long centered on describing how it helps to recognize and identify objects in the visual world. Dr. Todd Handy’s research examines the reverse: the effect movements and locomotion have on vision, which is a previously unexplored facet of visual-motor interactions. Using a system that provides video-simulated motion and measurements of brain activity, Dr. Handy is studying how visual attention automatically responds to the many perceptual demands of locomotion – keeping track of the direction one is heading, recognizing stationary obstacles that may be looming in the path, and noticing moving objects in the periphery that may ultimately be on a collision course without conscious attention to these elements. Dr. Handy hopes his research will contribute to a better understanding of these visual-motor interactions and may provide a promising new method of diagnosing clinical motor disorders.