Vision serves two purposes: it allows us to consciously perceive our surroundings (e.g. recognize an object) and to act upon this environment (e.g. reach for the object). However, one or the other of these capabilities is often impaired in people with brain disorders, such as dementia or schizophrenia. While a wealth of research has been conducted on visual perception, less is known about visually guided actions, or how perception and action work together. The dual systems theory of vision allows for the possibility that there are separate attention systems for action and perception in the brain. Geniva Liu’s research focuses on improving understanding of how perception and action interact in vision. Results from the research could contribute to the design of strategies to help people with attention deficits capitalize on alternative resources for visually guided action or perception.
Research Pillar: Clinical
Spine biomechanics in osteoporotic thoracic vertebrae: investigating the safety of manual therapy
People with spinal osteoporosis often suffer back pain that cannot be relieved by exercise or medication. Physiotherapists with advanced training can use manual spinal joint mobilization techniques, also called manual therapy, to relieve the pain. However, there are questions about how safe the therapy is and whether the techniques pose a risk of causing fractures. Meena Sran is using bioengineering techniques to determine if manual therapy creates a risk of fracture in people with spinal osteoporosis. Besides assessing the spine’s ability to resist fracture during manual therapy by determining the pressure required to fracture vertebrae, she is also examining whether or not x-rays and CT scans can detect these fractures. The study will provide insights into the safety of manual therapy and ultimately help improve treatment of back pain in older adults with spinal osteoporosis.
The value of cardiac specific troponin in predicting cardiac outcomes in an asymptomatic chronic kidney disease population
Chronic kidney disease is associated with a high risk for heart attack, even after accounting for traditional cardiac risk factors such as smoking and high cholesterol. The risk increases as kidney function deteriorates. Elevated levels of a cardiac enzyme called cardiac specific troponin (cTn) have been shown to predict heart attack or death in people with acute coronary conditions. Some studies also suggest that elevated cTn can predict cardiac outcomes in patients with chronic kidney disease who do not present cardiac risk factors. Nadia Khan is researching whether elevated levels of cTn can be used to accurately predict heart attack and death in patients with different levels of chronic kidney disease. The results could help clinicians identify patients with chronic kidney disease who are at high risk of heart disease, and also provide the foundation for developing therapies that prevent cardiac disability and death in this patient population.
The effects of a community-based exercise program on cognitive function and falls in older women with a history of falls: a 12-month randomized controlled trial
Falls are the most frequent cause of injuries and injury-related death in older people. Recent guidelines on preventing falls recognize cognitive impairment as a leading risk factor. People with cognitive impairment have 2.2 times greater risk for falls causing injuries and 1.7 times the mortality rate of older adults with regular cognitive function. Research on falls has not determined which domains of cognition — including attention, memory and perception — figure most significantly in this increased risk. Dr. Teresa Liu-Ambrose is investigating the specific dimensions of cognition most strongly associated with falls in older women. She is also examining the impact of a 12-month exercise program on these dimensions, and the relationship between changes in cognitive function and incidence of falls. Results from the study could contribute to the design of exercise programs to help prevent falls in older people.
The development of a method to study biomechanics of bronchial smooth muscle obtained from endobronchial biopsy
Dr. Brent McParland believes the key to improving care for asthma lies in understanding the underlying mechanisms that cause airway narrowing. In asthma, the airways narrow too much and too easily when exposed to stimuli such as pollens and cat hair. The amount of airway smooth muscle (ASM) is increased in people with asthma, which should mean that asthmatic airways develop more force than non-asthmatic airways. Yet studies have not shown more force in asthmatic airways, as might be expected with more muscle. However, these studies did not assess the ability of the muscle to shorten, which causes the airway to narrow. Dr. McParland is developing a method of obtaining very small airway tissue samples from lung surgeries for use in measuring smooth muscle shortening. He will use the method to compare the airway smooth muscle in normal and asthmatic tissues. This research could result in a better understanding of the nature of exaggerated airway narrowing in asthma.
Synaesthesia: A window into abnormal perceptual experiences
Synaesthesia is a fascinating condition in which individuals can experience tactile sensations when they taste foods or perceive colours when they hear sounds. Very little is known about the brain activity underlying this condition. Although synaesthesia occurs in healthy people, synaesthetic experiences are reminiscent of the abnormal perceptions that occur in other disorders such as schizophrenia. Dr. Daniel Smilek is using neuroimaging techniques to investigate the brain activity associated with this condition. Results from the research could provide insight into the brain processes involved with abnormal perception in various syndromes, such as schizophrenia, as well as the processes underlying perception in normal individuals.
Baseline HIV RNA and mortality after the initiaton of HARRT: Exploring the mechanism that explains the association
Before triple-drug antiretroviral therapy was developed to treat HIV, certain levels of HIV ribonucleic acid (RNA) in the blood were strongly associated with progression of the disease. However, there has been a great deal of uncertainty about the clinical relevance of HIV RNA levels since the therapy was introduced. Recent studies have produced conflicting results about the association of HIV RNA levels with survival or death for individuals with HIV. But these studies did not assess patient adherence to triple-therapy treatment. Dr. Evan Wood is using data from the BC Centre for Excellence in HIV/AIDS Drug Treatment Program to research the association between HIV RNA levels and survival after beginning triple-drug antiretroviral therapy. He is also investigating the relationship between HIV RNA levels and factors such as non-compliance with triple therapy treatment. The findings could be used to adapt provincial guidelines for HIV/AIDS treatment.
Muscle metaboreflex during exercise in chronic obstructive pulmonary disease
Chronic Obstructive Pulmonary Disease is a progressive lung disease that causes breathing difficulties and chronic cough. Those affected often have weak arm and leg muscles that are easily fatigued, which can cause them to avoid exercise and adopt an inactive lifestyle. Dr. A. William Sheel’s research is directed at understanding how reduction in blood flow and oxygen during exercise leads to muscle fatigue and how different types of exercise affect the amount of fatigue. Results from his study will help explain why people with chronic lung disease become prematurely fatigued and could be used to design exercise rehabilitation programs to improve their health.
Chronic psychological stress and immune system dysregulation
Research has shown that chronic stress negatively affects health. One model suggests that chronic stress suppresses immune function, leaving people more vulnerable to infectious diseases and cancers. However, it doesn’t explain how stress affects conditions that result from over-activation of the immune system, such as autoimmune, arthritic and cardiovascular disorders. To investigate how stressors interfere with the immune system’s ability to turn itself off once activated, Dr. Miller is comparing the immune responses of two groups: parents with a severe chronic stressor (a child undergoing cancer treatment), and parents of healthy children. Results from the research could increase knowledge about the ways stressors affect health, including confirmation that one of the effects is interference with the immune system’s ability to turn off responses against bacteria. As part of this study, Dr. Miller is also examining whether supportive personal relationships act as a buffer against chronic stress.
CHIPS (control of hypertension in pregnancy study): a pilot trial
Almost 10 per cent of women who become pregnant develop hypertension (high blood pressure). Experts agree that pregnant women with severe hypertension should receive blood pressure medication to protect them from stroke. However, it is not clear if or how much the medication would benefit pregnant women with mild to moderate hypertension. A complicating factor is that the medication may also contribute to poorer growth and lower birth weight in babies, placing them at increased risk for health problems as newborns, children and adults. According to a national survey, Canadian obstetricians are unsure about prescribing blood pressure medication to women with mild to moderate hypertension. To help clarify the issue, Dr. Laura Magee and her research team have designed a Control of Hypertension in Pregnancy Study (CHIPS), aimed at determining if it is better for the baby (i.e. better growth before birth and better health thereafter) to allow a mother’s blood pressure to be higher than normal during pregnancy or to prescribe blood pressure medication to lower it. To begin, Dr. Magee is conducting a pilot trial to assess whether or not physicians would adhere to the treatment protocols in a full trial and to confirm if sufficient patients could be enrolled. If the pilot study indicates that CHIPS is feasible, the full trial will be conducted at major maternity centres across Canada.