Cognitive and Visual Speech Contributions to Speech Perception in Challenging Listening Conditions

Speech perception routinely takes place in noisy or degraded listening environments, leading to ambiguity in the identity of the speech token. Here, I present one review paper and two experimental papers that highlight cognitive and visual speech contributions to the listening process, particularly in challenging listening environments. First, I survey the literature linking audiometric age-related hearing loss and cognitive decline and review the four proposed causal mechanisms underlying this link. I argue that future research in this area requires greater consideration of the functional overlap between hearing and cognition. I also present an alternative framework for understanding causal relationships between age-related declines in hearing and cognition, with emphasis on the interconnected nature of hearing and cognition and likely contributions from multiple causal mechanisms. I also provide a number of testable hypotheses to examine how impairments in one domain may affect the other. In my first experimental study, I examine the direct contribution of working memory (through a cognitive training manipulation) on speech in noise comprehension in older adults. My results challenge the efficacy of cognitive training more generally, and also provide support for the contribution of sentence context in reducing working memory load. My findings also challenge the ubiquitous use of the Reading Span test as a pure test of working memory. In a second experimental (fMRI) study, I examine the role of attention in audiovisual speech integration, particularly when the acoustic signal is degraded. I demonstrate that attentional processes support audiovisual speech integration in the middle and superior temporal gyri, as well as the fusiform gyrus. My results also suggest that the superior temporal sulcus is sensitive to intelligibility enhancement, regardless of how this benefit is obtained (i.e., whether it is obtained through visual speech information or speech clarity). In addition, I also demonstrate that both the cingulo-opercular network and motor speech areas are recruited in difficult listening conditions. Taken together, these findings augment our understanding of cognitive contributions to the listening process and demonstrate that memory, working memory, and executive control networks may flexibly be recruited in order to meet listening demands in challenging environments.

Energizing the Oak Ridges Moraine? Analyzing the Policy Implications of Three Wind Energy Developments on the Oak Ridges Moraine and their Potential Impact on the Coordinated Land Use Planning Review through the Involvement of First Nations and Environmental Non-governmental Organizations

This research explores the policy implications of the approval of three wind energy projects on the Oak Ridges Moraine, and their impact on the Coordinated Land Use Planning Review process. Specifically, it focuses on the involvement of First Nations and environmental non-governmental organizations (ENGOs). This research was conducted through analyzing submissions to the Coordinated Land Use Planning Review, related legislation and policy, Environmental Review Tribunal hearing documents, and interviews with key informants. This research culminates in a number of recommendations to the Coordinated Review informed by the analysis.

Weight Loss in the Chiropractic Profession

Background: Excess weight places a significant burden on health. Clinical practice guidelines advise healthcare professionals to provide weight management interventions to patients with overweight and obesity. Chiropractic practice may provide a unique opportunity to deliver weight management interventions to those with overweight and obesity. However, little has been done to address overweight and obesity within the chiropractic profession. Identifying the extent of this evidence-practice gap in chiropractic practice is the first step in addressing this issue. Objectives: This thesis was to assess the clinical practices of weight loss provided by chiropractors. The primary objectives were to 1) determine the prevalence of overweight and obesity in the adult patient population that sought chiropractic care, 2) describe the frequency and distribution of chiropractor directed weight management intervention, 3) identify associations between chiropractor directed weight management interventions and specific patient-level and chiropractor-level variables, and 4) examine the interaction between patient weight and comorbid conditions and whether chiropractors offered weight management interventions. Methods: Data from the Ontario Chiropractic Observational and Analysis Study was used (N = 42 chiropractors, N = 3523 patient encounters). Multilevel logistic regression was performed. Patient-level as well as chiropractor-level variables were investigated and associations with weight management provided by chiropractors were identified. Results: The majority of patients who sought chiropractic were overweight or obese (61.2%). Weight loss was provided to only 5.4% of patients. Chiropractors who graduated between 1995 and 2005 (OR: 0.02, 95% CI: 0.00 - 0.13) or prior to 1995 (OR: 0.08, 95% CI: 0.01 - 0.42) provided weight management significantly less than chiropractors who graduated between 2005 and 2014. No significant interaction was observed between patient adiposity and comorbid conditions with chiropractors directed weight loss. Conclusion: The majority of patients who seek chiropractic care are overweight and obese. Chiropractors are in a unique position to help improve patient health through offering weight management. However, this opportunity has not been fully realized by the chiropractic profession.

Weight Loss in the Chiropractic Profession

Background: Excess weight places a significant burden on health. Clinical practice guidelines advise healthcare professionals to provide weight management interventions to patients with overweight and obesity. Chiropractic practice may provide a unique opportunity to deliver weight management interventions to those with overweight and obesity. However, little has been done to address overweight and obesity within the chiropractic profession. Identifying the extent of this evidence-practice gap in chiropractic practice is the first step in addressing this issue. Objectives: This thesis was to assess the clinical practices of weight loss provided by chiropractors. The primary objectives were to 1) determine the prevalence of overweight and obesity in the adult patient population that sought chiropractic care, 2) describe the frequency and distribution of chiropractor directed weight management intervention, 3) identify associations between chiropractor directed weight management interventions and specific patient-level and chiropractor-level variables, and 4) examine the interaction between patient weight and comorbid conditions and whether chiropractors offered weight management interventions. Methods: Data from the Ontario Chiropractic Observational and Analysis Study was used (N = 42 chiropractors, N = 3523 patient encounters). Multilevel logistic regression was performed. Patient-level as well as chiropractor-level variables were investigated and associations with weight management provided by chiropractors were identified. Results: The majority of patients who sought chiropractic were overweight or obese (61.2%). Weight loss was provided to only 5.4% of patients. Chiropractors who graduated between 1995 and 2005 (OR: 0.02, 95% CI: 0.00 - 0.13) or prior to 1995 (OR: 0.08, 95% CI: 0.01 - 0.42) provided weight management significantly less than chiropractors who graduated between 2005 and 2014. No significant interaction was observed between patient adiposity and comorbid conditions with chiropractors directed weight loss. Conclusion: The majority of patients who seek chiropractic care are overweight and obese. Chiropractors are in a unique position to help improve patient health through offering weight management. However, this opportunity has not been fully realized by the chiropractic profession.