Background: Many adolescents and young adults (AYAs) aged 15-39 years describe struggling with cancer-related cognitive impairment (CRCI) after treatment. CRCI (e.g., memory, concentration, and learning difficulties) often causes distress, diminishes quality of life (QoL), and impedes young adults' participation in academic, recreational, and social experiences. Yet, CRCI is poorly understood in AYAs and options to prevent or treat this burdensome side effect are lacking. Based on growing evidence suggesting that physical activity (PA) may enhance cognitive function in older adults, individuals with diseases of cognition, and breast cancer survivors, research exploring links between PA and CRCI in AYAs is warranted. Thus, the purpose of this observational, mixed methods thesis was to explore how AYA cancer survivors experience and cope with CRCI, taking into consideration potential predisposing factors (i.e., medical, psychological), interventional strategies (i.e., PA), and outcomes (i.e., QoL). Methods: Over a nine-month period, 90 AYAs who had completed primary cancer treatment self-referred; 49 were eligible and enrolled into the study. Of these, 46 participants (M_age=31.4±5.4; 91.3% female; 39.1% blood cancer) completed an online survey and three web-based neuropsychological tests; semi-structured interviews were conducted on a rolling basis with a sub-set (n=16) who reported clinically meaningful CRCI. Quantitative data were analyzed descriptively and qualitative data were analyzed thematically. Results: Overall, participants were active based on their self-reported moderate-to-vigorous intensity PA (MVPA; M=27.3±20.6) and relative to scale ranges, they reported moderate levels of depressive symptoms, stress, fatigue, and quality of life (M=12.1±5.5; M=21.1±7.2; M=25.2±11.5; M=68.8±18.3, respectively). On average, participants reported clinically meaningful CRCI (M=44.7±17.4), and as compared to normative values, their neuropsychological test scores indicated poor executive functioning and processing speed, but not working memory. Bivariate correlations between cognitive function (self-reported and objective) and medical characteristics (i.e., time since diagnosis, cancer stage, chemotherapy exposure) had small-to-moderate effect sizes. Small-to-large correlations were observed between cognitive function and psychological factors (i.e., depressive symptoms, stress, fatigue, QoL). Finally, correlations between cognitive function and MVPA were favourable, though effect sizes were small. Moreover, qualitative data provided insight into how AYAs experience and cope with their cognitive impairment, which was summarized within four themes: (1) descriptions and interpretations of the CRCI phenomenon, (2) effects of CRCI on day-to-day life and QoL, (3) cognitive-behavioural self-management strategies, and (4) recommendations for improving care. Conclusion: Results confirm that cancer can impact AYAs' cognitive function and have detrimental effects for their daily life and overall QoL. AYAs reported using various cognitive-behavioural self-management strategies, including PA; taken together with quantitative data, findings suggest that PA may be a promising strategy to cope with CRCI. However, high-quality experimental research is needed to confirm this association, test the processes by which this may occur, as well as to determine optimal PA dosages/contexts for managing CRCI.

No description available.

Parkinson’s disease (PD) is a neurodegenerative disorder associated with motor disturbance and non-motor symptoms (NMS). Although NMS such as sleep and circadian disruption, cognitive impairment, and mood disturbance are prevalent and debilitating, treatments are limited, owing to lack of knowledge about their etiologies and interactions. This project comprised two studies of NMS in mild to moderate idiopathic PD without dementia. The hypothesis of Study 1 was that disruption of rest-activity circadian rhythm contributes to cognitive impairment in PD independently of sleep disruption. Thirty-five participants underwent 7-10 days of actigraphy monitoring, which provided estimates of sleep and circadian functioning, and then neuropsychological testing. Hierarchical regression showed that circadian interdaily stability predicted executive function, visuospatial function, and psychomotor speed, though not memory, independently of sleep. Sleep efficiency independently predicted executive but not other cognitive function. Study 2 examined daily temporal associations between sleep, subjective cognition, and mood (anxiety, positive affect) in PD. Twenty participants used a smartphone app to engage in 14 days of ecological momentary assessment (EMA) of daytime symptoms and subjective sleep quantity and quality. They wore actigraphs for objective sleep assessment. The hypothesis was that sleep quality would predict cognition and mood. Multilevel modeling indicated that subjective sleep quality was bidirectionally associated with mood on a day-to-day basis (i.e., last night’s perceived sleep affected today’s mood, which in turn will affect tonight’s sleep). There was also a trend for subjective sleep quality to predict the next day’s subjective cognitive function. Objective sleep was not associated with any daytime symptoms. Study 1 provided the first evidence that circadian rhythm contributes to cognition in PD independently of sleep. Study 2 indicated that, on a daily timescale, subjective sleep is relevant to mood and possibly cognition in PD, whereas objective sleep is either insufficiently sensitive or not relevant. Together these findings support the use of EMA to investigate small-timescale interactions among NMS, and present circadian rhythms and sleep perception as intervention targets for improving cognition and mood, and ultimately for enhancing quality of life in PD. / 2020-02-15T00:00:00Z

No description available.

No description available.

No description available.

No description available.

No description available.

While the physical health benefits of exercise are well established, mental health benefits remain unclear. The literature reports reduced stress and improved cognitive function in rodent exercise studies, and improved mood scores in humans. However, though mood disorders are characterized by poor response to treatment, studies rarely evaluate difficult-to-treat patients or functional outcomes. Therefore, we evaluated the impact of 12-week, group-based exercise programs (running or yoga) on mood and functional outcomes including health-related quality of life (HRQOL) and social and cognitive functioning. Methods: Study 1 was a retrospective review of mood and stress outcomes in participants with difficult-to-treat mood disorders. In Study 2, we measured functional outcomes before and after the running program in a subsample from Study 1. Improved friendship and high injury rates in the running group inspired Study 3, a randomized control trial to evaluate mood and functional outcomes in a non-clinical sample using yoga, a low-impact exercise program that included cognitive control. Results: In Study 1 (n=46), depression (p<0.0001) and stress (p=0.01) scores improved over time, and improved friendship levels were predictive of improved mood scores (p<0.04). In Study 2 (n=18), we found improved scores on several HRQOL subscales, including social functioning (p-values<0.01) and weak improvements in working memory and processing speed (p-values<0.04). In Study 3, yoga participants (n=20) had improved stress (p=0.02), loneliness (p=0.002), and HRQOL (p-values<0.03) scores, compared to wait-list controls (n=8). Yoga participants improved on tasks reflecting hippocampal memory (p-values<0.006) and attention and inhibitory control (p=0.03). Regression and mediation analyses suggest that social support mediates the stress-reducing impact of yoga (p-values<0.0005). Discussion: Group-based exercise programs impart benefits across mental health and functional outcomes for participants with and without mood disorders. Exercise may be an effective adjunctive treatment for mood disorders, and more data is needed on how social support impacts clinical outcomes. / Thesis / Doctor of Philosophy (PhD) / This dissertation examines the impact of exercise across multiple indications of mental health and functioning including mood scores, stress, cognitive function, social function and health-related quality of life (HRQOL) in participants with and without mood disorders. Youth and adults engaged in 12-week group-based exercise interventions of running or yoga and completed comprehensive mental health and neurocognitive assessments. Results: Participation in a structured exercise program was associated with improved stress and depression, social functioning, physical and mental HRQOL domains and limited improvements in cognitive function. Results also support therapeutic benefits of structured high- and low-intensity exercise programs across multiple symptoms in patients with difficult-to-treat mood disorders, and further suggest that reduced stress and increased social functioning play key roles in the mental health benefits observed. These results represent a new standard for mood disorders research, to better understand the how lifestyle strategies are effective for the treatment of mental illness.

Concussion, defined as a functional injury with complex symptomatology, affects millions annually and has been classified as a serious public health concern. Clinical tools currently available for concussion assessment fail to objectively measure cognitive function and thus, are inadequate for proper evaluation of the cognitive dysfunctions associated with the injury. As a result, investigation into the neurological consequences associated with concussion has become a prominent focus in neuroscience research. Traditionally, neuroimaging methods have been used primarily on concussion detection, while behavioural and neuropsychological assessments have been used for both concussion detection and cognitive-performance tracking. However, to date, minimal work has explored the use of neuroimaging to track the consequences of concussion at the neurophysiological level. Accordingly, the present thesis sought to investigate the clinical applicability of electroencephalography (EEG) as an effective neuroimaging tool capable of concussion detection, as well as its ability to objectively track neurophysiological changes over time. Event-related potentials (ERPs) were used to assess specific functions, or more accurately, dysfunctions of select cognitive processes as reflected by electrophysiological changes in the brain. Specifically, the Mismatch Negativity (MMN), N2b, and P300 were investigated to evaluate memory, attention, and executive control in concussed populations. The results of this thesis demonstrated alterations in each of the aforementioned ERPs, signifying cognitive dysfunctions linked to neurophysiological abnormalities in concussed populations. Of particular importance, Chapter 2 revealed the first instance of MMN abnormalities in a concussed population, Chapter 3 was the first to assess concussed adolescents at the acute stage of their injury, and Chapter 4 demonstrates the potential of ERPs to track neurophysiological changes from the acute to post-acute stages of the injury. Ultimately, the findings presented in this dissertation support the clinical viability of using ERPs to not only detect cognitive dysfunctions associated with concussion, but also to objectively track neurophysiological changes on the path to recovery. / Dissertation / Doctor of Philosophy (PhD)