As populations around the world growing old, age-related diseases, such as Alzheimer’s disease, the most common type of dementia, will become more common. We don’t yet have any way to cure Alzheimer’s disease, so prevention is key. We study factors that put people at risk of Alzheimer’s disease to inform prevention strategies to address those risk factors.
Some people show no memory loss or other symptoms of Alzheimer’s disease during life, but after death their brains show all the signs of this disease. How do these people resist the usual consequences of an Alzheimer brain? We call this cognitive reserve. Strategies to build cognitive reserve have the potential to prevent or at least delay Alzheimer’s disease and other causes of cognitive decline, and thus increase the chance of healthy aging for all.
Investigating how some individuals age well provides us with clues on how to maximize the chances of healthy aging for all. In contrast to many age-related diseases, we do not have a standard way to define healthy aging, and we know less about what goes well in healthy aging than what goes wrong in many age-related diseases.
In our lab we investigate the impact of factors across the life course, from birth (e.g., genes) and early life (e.g., high school grades, multilingualism) through to late life (e.g., stroke). We have looked at different populations to examine different factors. For example, the Nun Study is a rich source of early-life data, such as high school grades, emotions, and linguistic ability. We are linking these factors to memory and other cognitive abilities in late life and to brain autopsies after death.
Current Projects
Stress and Cognition in Aging Refugee, Immigrant, and Non-Immigrant Canadians
The pre- and post-migratory experiences of refugees and immigrants are stressful and has been shown to lead to poor physical and mental health, increasing risk for a later dementia diagnosis. Few studies have assessed physiological stress (cortisol) or cognitive function in refugees. The purpose of this study will be to study the effects of chronic stress on cortisol and its association with cognitive function in aging refugees, immigrants, and non-immigrant Canadians in the Region of Waterloo.
Depression and Cognitive Decline
Depression is a common mood disorder and the leading cause of disability world-wide. We are investigating the association between depression and cognitive decline in Canadians aged 45 to 85 years in the Canadian Longitudinal Study on Aging. We will determine whether the impact of mid- and late-life depression on cognition differs over time, whether this impact varies by age and sex, and whether social isolation explains why individuals with depression may be more likely to develop cognitive decline.
Protective Effects of Multilingualism on Cognitive Impairment
Multilingualism is a cognitively stimulating activity that may increase cognitive reserve and reduce the risk of cognitive impairment. We will determine whether the number, type and similarity of languages reduce the risk of cognitive impairment in more than 20,000 Canadians 45 to 85 years of age. By contributing to our understanding of the impact of multilingualism on cognition, our study will help to identify protective factors to maintain cognition and promote healthy aging.
Inflammaging and Cognitive Decline
With advancing age, we become more vulnerable to the deleterious effects of chronic stress. These age-related changes result in inflammaging. Inflammaging has detrimental effects throughout the body; in particular, it may accelerate age-related cognitive decline. To support the health of older Canadians, we need to understand the factors that put them at risk for cognitive impairment. Our study will investigate the impact of stress on cognition in older adults, and the inflammatory mechanisms through which it acts.
Social Isolation and Cognitive Decline
Social interaction and cognitive function are critical to aging well, but their connection is not well understood. To understand these complex links, we will analyze information from middle-aged and older Canadians collected across two points in time, spread three years apart. Our research will explore the impact of social isolation and related factors (e.g., loneliness, social support) on cognitive function, and identify vulnerable subgroups who may benefit most from interventions to address social isolation and thereby improve cognitive function.
Anxiety, Social Support, and Cognitive Decline
Anxiety is a common but underdiagnosed condition in older adults that has been linked to lower social support and cognitive function. Using data from the Canadian Longitudinal Study on Aging, we examine whether anxiety is linked to later cognitive decline, whether individuals with anxiety may be more likely to develop cognitive decline because their anxiety reduces the availability of social support, and whether this relationship varies by age and sex.
Early-life Factors and Later-life Cognitive Reserve
Studying the relationship between early-life factors and later-life cognitive reserve on the development of dementia is essential to prevent dementia in an aging population. If individuals with Alzheimer’s neuropathology do not present clinical expression of dementia (having high cognitive reserve), then we have significantly diminished the effects of dementia on individuals and society. Utilizing already collected data from the Nun Study, we will explore the impact of early-life educational level and academic performance on cognition in later-life while also controlling for Apolipoprotein E status.
Past Projects
Cognitive Reserve and Improvement from Mild Cognitive Impairment to Normal Cognition
While mild cognitive impairment (MCI) strongly increases the risk of dementia, not all individuals with MCI end up developing dementia. What determines who progresses to dementia vs who reverts back to normal cognition? We are studying whether age and genetic risk in addition to indicators of cognitive reserve (educational level, school grades, and written language skills) determine whether individuals with MCI improve to normal cognition or decline to dementia. Identifying predictors of improvement will inform strategies to prevent dementia.
Associations between Social Isolation, Anxiety, and COVID-19 Testing
Since the beginning of the pandemic increases in social isolation have made it more difficult to cope with the anxiety surrounding the rapid changes and uncertainty that have come with COVID-19. However, little research has investigated whether those who were at increased risk for social isolation also reported higher anxiety. Further, no research has assessed whether this relationship changed for those who had to test for COVID-19 compared to those who didn't. This exploratory study will asses the relationships between social isolation, anxiety, and COVID-19 testing using the Canadian Longitudinal Study of Aging.