Trainee Schedule

Virtual Reality Exposure Therapy Reducing Responsive Behaviors in Nursing Home Residents with Dementia: A Case Series

OBJECTIVE: People with advanced dementia often exhibit responsive behaviors such as apathy, depression, agitation, aggression, sleep disorders, and psychosis causing physical and emotional harm to the individual and their caregivers. Non-pharmacological approaches are now a first-line strategy to manage responsive behaviours in clinical practice because of potential risks associated with the use of antipsychotic medications. The objective of this study is to evaluate whether virtual reality exposure therapy a feasible non-pharmacological approach to reduce responsive behaviors in nursing home residents with advanced dementia. METHODS: We conducted a single site case series with a convenience sample (N=24; age=85.8 ±8.6 years; Cognitive Performance Scale score=3.4 ± 0.6). Our intervention was 30 minutes of customized immersive three-dimensional virtual reality delivered using remote-controlled projectors for five days a week for two weeks. Primary outcome was feasibility and secondary outcome was change in responsive behaviours pre-and-post-intervention. RESULTS: The intervention was feasible with 0% attrition. The average length of each session was 22 minutes. Eighteen out of 24 of participants were able to complete 8/10 of the sessions. No related adverse events were registered. A clinically significant change in depression (ES= 0.4, p≤0.05) and in agitation (ES= 0.2, p<0.06) was observed with Cornell Scale for Depression in Dementia and Cohen-Mansfield Agitation Inventory. CONCLUSION: Virtual reality exposure therapy is a safe and feasible non-pharmacological approach. Our intervention is remote-controlled, does not need a headset, and is compatible with COVID-19 infection prevention policies; promising a novel approach to reduce responsive behaviors. A future RCT can confirm our results.

Retention of practice effects on a complex walking task is enhanced by a single session of prefrontal brain stimulation in older adults

Introduction: Older adults often have poor walking skills which may increase fall risk. Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulatory adjuvant shown to enhance motor skills through long-term potentiation-like plasticity. We tested the hypothesis that a single session of prefrontal tDCS during complex walking practice would facilitate greater locomotor learning and retention of practice-related gains in walking in older adults, compared to sham and no-tDCS conditions. Methods: Fifty older adults aged 65 to 92 years were randomized to receive either active (20 minutes at 2mA intensity), sham (30 seconds at 2mA) or no-tDCS. For the learning session, tDCS was administered bilaterally to the prefrontal cortex during ten trials of walking practice on a 10-meter complex obstacle course. Retention of walking gains was assessed one week later. Obstacle walking speeds were normalized as a percentage of the participants 10-meter fastest unobstructed walking speed Results: At the learning session, the active group significantly increased their obstacle walking speed from 37% to 44% of fastest unobstructed speed (p<0.01). Similarly, the learning effects were also significant for sham (35% to 50%) and no-tDCS (42% to 50%) groups. At the retention session, only the active group exhibited significant offline gains and continued improvement in obstacle walking speed (44% to 48%, p=0.004). Retention effects were not significant for sham (50% to 52%) and no-tDCS (50% to 48%) groups. Discussion: Prefrontal tDCS may facilitate the offline consolidation of practice effects to enhance the retention of walking gains between-sessions. Sham tDCS may have a placebo effect that enhanced within-session learning.

The effect of exercise on falls in older adults living with dementia: A systematic review

Introduction: Whether exercise reduces falls in people living with dementia (PWD) is not clear. We conducted a systematic review of randomized controlled trials (RCTs) examining the efficacy of exercise to reduce falls and injurious falls relative to usual care among PWD. Methods: We included peer-reviewed RCTs evaluating any mode of exercise on falls and injurious falls among PWD. We excluded studies if they did not solely involve PWD and if they were not the key publication of the RCT with falls as an outcome. We searched AgeLine (1978-Present), the ALOIS (i.e., Cochrane Dementia and Cognitive Improvement Group’s Specialized Register), and grey literature on August 19, 2020. We removed duplicates, and screened titles, abstracts, and full-texts. We evaluated the risk of bias using the Cochrane Risk of Bias Tool and study quality using the Consolidated Standards of Reporting Trials. Results: Ten studies were included (n=1713; age: 80.7±7.0 years; female: 58.1%; Mini-Mental State Examination: 19.8±4.2points; intervention duration: 27±17.8 weeks; adherence: 73.0±15.4%; attrition: 22.1±12.5%). Exercise reduced falls in 1/10 studies (incident rate ratio=0.44 [0.32,0.56]); all other studies reported null findings. No studies (0/4 studies) found an effect for injurious falls. All studies had risk of bias, notably: 1) they were not powered for falls (10 studies, 100%); 2) the assessors became unblinded (2 studies, 20%); and 3) they had short intervention durations (≤4 months; 5 studies, 50%). The quality of reporting was good (79.5±10.8%). Discussion: Exercise does not appear to prevent falls or injurious falls in PWD; higher quality research is needed.

Comparing the effects of outdoor versus indoor walking on cognitive and physical function in older adults with mild cognitive impairment

INTRODUCTION: Aerobic exercise (AE) is a promising strategy to mitigate cognitive and physical decline in older adults with mild cognitive impairment (MCI). Evidence suggests that outdoor, natural environments, as compared to indoor or built environments, may augment the health benefits of AE. However, the potential utility of green exercise among older adults requires further investigation. Objectives:• Primary: To compare the cognitive effects of 12 weeks of moderate-intensity outdoor forest walking (OUT) versus indoor treadmill walking (IN) among older adults with MCI. • Proof-of-Concept: To demonstrate recruitment rate, withdrawal rate, adherence, adverse events, and acceptability. METHODS: Study Design: A 12-week, single-blinded, 2-arm, proof-of-concept RCT: OUT and IN (1:1). Measurement will occur at baseline and at trial completion. Participants: 68 community-dwelling adults aged 65-80 years old with MCI. Interventional Arms: Both OUT and IN will involve three supervised, group-based training sessions per week for 12 weeks. Each session will comprise 10 min warm-up, 40 min moderate-intensity AE (progressing from 45% to 75% of heart rate reserve), and 10 min cool-down. AE will involve walking or jogging outdoors in an urban forest (OUT) or indoors on treadmills (IN). Outcomes: • Primary: Working memory (National Institutes of Health Toolbox (NIHTB) List Sorting Test; Verbal Digits Forward and Backward Test). • Secondary: Cognitive function (NIHTB; Digit Symbol Substitution Test); motor function (Short Physical Performance Battery; Timed Up and Go Test); affective outcomes (anxiety; depression; affective responses to exercise); blood pressure; physical activity level; sleep quality; and quality of life. DISCUSSION: We welcome suggestions for improving trial design.

Medial Temporal Lobe Cortical Changes In Response To Exercise Interventions In Women With Early Psychosis: A Randomized Controlled Trial

Objective: Exercise has been shown to induce changes in hippocampal volume in individuals with psychosis, but its ability to impact cortical regions remains equivocal. Psychosis patients are observed to have neuroanatomical deficits in the prefrontal-limbic network, associated with greater positive symptom severity and cognitive impairment. Despite the fact that women have greater potential to benefit from exercise interventions due to greater exercise-induced upregulation of brain growth factors, women with psychosis have been under-represented in exercise intervention studies. We hypothesized that women with early psychosis who complete an aerobic exercise intervention would demonstrate significant increases in prefrontal-limbic cortical regions and these neuroplastic changes would be associated with reduced symptom severity. Methods: In a cohort of 51 women with early psychosis from Hong Kong, we investigated the effects of a twelve-week exercise intervention (yoga, aerobic or waitlist group) on cortical grey matter. Clinical assessments and structural MRI were completed at the beginning and end of the intervention. Results: Increases in cortical volume and thickness were observed in the medial temporal cortical regions, primarily in the entorhinal and fusiform temporal gyrus for participants who completed the aerobic intervention. For the aerobic group only, increases in the entorhinal and fusiform temporal gyri were associated with decreasing psychosis symptom severity, particularly for the general psychopathology subscale. Conclusions: Neuroplastic increases in cortical grey matter were observed in women with early psychosis and these exercise-induced changes were associated with improvements in psychosis symptom severity. Psychosis patients may benefit from aerobic exercise interventions as a safe, adjunct treatment.

Physical activity in older adults who are cognitively impaired without dementia: what happens vs. what is possible

Introduction: Physical inactivity may increase risk of progression to dementia in people with cognitive impairment that is not severe enough to meet criteria for dementia (Cognitive Impairment, No Dementia: CIND), but little is known about the factors associated with physical inactivity in this group. Methods: We studied 1875 community dwelling adults (over age 65) with CIND in the Health and Retirement Study. Unadjusted and adjusted associations of physical inactivity (moderate vigorous physical activity [MVPA] ≤1x/week) with sociodemographic, health, and physical function variables were assessed using chi-square and modified Poisson regression adjusted for age, sex, and race/ethnicity. In participants who were physically inactive, we also determined whether they were capable of greater MVPA. Results: Mean participant age was 77 and 58% were women. The prevalence of physical inactivity was 56%. The largest adjusted risk ratios (aRR [95% CI]) for physical inactivity were self-rated health as poor (77%; aRR: 2.28[1.58–3.30]) and fair (63%; aRR: 1.88[1.29-2.74]) versus excellent (34%), and difficulty walking across the room (87%; aRR: 2.10[1.88–2.34]) and one block (79%; aRR: 1.91[1.68-2.18]) versus no difficulty (41%). Physical inactivity was also associated with older age, women, lower total assets, lower education, specific health conditions, depression, higher BMI, current smoking, not drinking alcohol, and significant pain. Sixty-one percent of physically inactive participants were capable of greater MVPA. Discussion: More than half of older adults with CIND are physically inactive, yet most are capable of greater MVPA. Study findings suggest a need for physical activity interventions for older adults with CIND.

An investigation of the relationship between hemodynamics and executive function across a continuum of exercise intensities

Executive functions are high-level cognitive processes that encompass response inhibition, task-updating and set-shifting. Importantly, a single bout of aerobic exercise has been shown to provide a transient executive benefit related to an increase in cerebral blood flow (CBF). However, whether increases in CBF are responsible for an executive improvement across a continuum of intensities is unknown. Here, participants completed four experimental sessions: a V̇O2peak test to determine cardiorespiratory fitness and lactate threshold (LT); and separate 10-min sessions of light- (i.e., 25 W), moderate- (i.e., 80% estimated LT), and heavy- (i.e., 15% of the difference between LT and V̇O2peak) intensity exercise. An estimate of CBF was achieved via transcranial Doppler ultrasound and near-infrared spectroscopy that monitored blood velocity (BV) and deoxygenated hemoglobin (HHb), respectively. Executive function was assessed before and after each session via the antisaccade task. Antisaccades are goal-directed eye-movements mirror-symmetrical to a presented target, and are mediated via executive networks that demonstrate task-dependent modulation following acute and chronic aerobic exercise. Prosaccades (i.e., non-executive saccade to veridical target location) were also included to determine whether exercise-induced increases in CBF were specific to executive-related oculomotor control. Results showed that BV increased according to exercise intensity, whereas HHb decreased by a comparable magnitude across conditions. In terms of oculomotor performance, postexercise antisaccade, but not prosaccade reaction times were reliably shortened by a similar magnitude across the continuum of intensities used here. Accordingly, our results indicate the presence of a threshold after which increased CBF becomes superfluous to a postexercise executive benefit.

Association of Physical Activity Levels and Brain White Matter in Older Latino Adults

Background: Healthy brain white matter (WM) is pivotal to cognitive health in older adults. Greater levels of physical activity (PA) is associated with healthier WM. However, older Latinos engage in less PA than non-Latino whites.  Objective: Investigate the associations between self-reported PA and WM health (i.e., volume, integrity, and hyperintensities) in older Latinos. Methods: Participants were 34 cognitively healthy older Latinos from two cohorts who self-reported demographic information and PA levels (CHAMPS), and performed MRI. High-resolution three-dimensional T1- and T2-FLAIR weighted images and diffusion tensor imaging were acquired. We performed separate hierarchical linear regression models with the addition of relevant covariates. P-values were adjusted with Benjamini-Hochberg's false discovery rate procedure. Results: Controlling for intracranial volume, higher levels of leisure-time moderate-to-vigorous PA were associated with higher WM volume of the posterior cingulate (β = 0.220, SE = 0.125, 95% CI 0.009-0.431, p = 0.047) and isthmus cingulate (β = 0.212, SE = 0.110, 95% CI 0.001-0.443, p = 0.044). Higher levels of total PA were associated with higher overall WM volume of the posterior cingulate (β = 0.220, SE = 0.125, CI 0.024-0.421, p = 0.046) and isthmus cingulate (β = 0.220, SE = 0.125, 95% CI 0.003-0.393; p = 0.040). Significant p-values did not withstand adjustments. PA was not associated with WM integrity or hyperintensities. Conclusion: In older Latinos, higher levels of PA might be associated with greater WM volume in select regions key to brain network integration of physical and cognitive functioning. Further studies are needed to confirm associations.

Sweat the Fall Stuff: Physical Activity Moderates the Association of White Matter Hyperintensities with Falls Risk in Older Adults

Background: Falls in older adults are a major public health problem. White matter hyperintensities (WMHs) are highly prevalent in older adults and are a risk factor for falls. Physical activity (PA) is a promising countermeasure to reduce both WMHs and falls risk. However, no study has yet investigated whether PA attenuates the association of WMHs with falls risk. We hypothesised that PA moderates the association between WMHs and falls risk. Methods: Seventy-six older adults (70-80 years old) were included in this cross-sectional study. We indexed PA using the Physical Activity Score for the Elderly (PASE) Questionnaire. Falls risk was assessed using the Physiological Profile Assessment (PPA), and WMH volume (mm3) was determined from T2-weighted and PD-weighted MRI scans. We examined the independent associations of WMH volume and PASE score with PPA. Subsequently, we examined whether PASE moderated the relationship between WMH volume and PPA. We plotted simple slopes to interpret the interaction effects. Age, sex, and Montreal Cognitive Assessment (MoCA) score were included as covariates in all models. Results: Both PASE (β= -0.26 ± 0.11; p= 0.022) and WMH volume (β= 0.23 ± 0.11; p= 0.043) were each independently associated with PPA score. The interaction model indicated that PASE score moderated the association between WMH volume and PPA (β= -0.27 ± 0.12; p= 0.030), whereby higher PASE score attenuated the association between WMHs and falls risk. Conclusion: PA is an important moderator of falls risk. Importantly, older adults with WMH can reduce their risk of falls by increasing their PA.

Exploring the relationship between estimated cardiorespiratory fitness and mental health in thesis-based graduate students impacted by COVID-19

The COVID-19 lockdown has significantly impacted graduate student’s mental health. Physical activity is a promising strategy to mitigate the effects of COVID-19 on mental health by increasing cardiorespiratory fitness (CRF), a physiological adaptation to routine physical activity. Heart rate variability (HRV) is the beat-to-beat variability of the heart measured over a wide range and has been established as an index of favorable neurovisceral integration in response to environmental stress. CRF is positively linked with favorable resting HRV and HRV recovery following environmental stress. It is possible then that HRV might partially mediate the relationship between CRF and mental health. The present study will examine the relationship between mental health, CRF, and HRV in graduate students experiencing academic set backs due to the COVID-19 lockdowns. Using a cross-sectional approach, graduate students with varying fitness levels (as determined by the 6-minute walk test) will report on various aspects of their mental health (anxiety, depression, and COVID-related stress). Resting HRV will be captured using a validated smartphone app. We predict that higher CRF will correlate with better mental health, and that higher resting HRV will account for significant variance between the two. Results from this study will provide insight into the relationship between physical activity and mental health to help graduate students better cope with the stress of the pandemic.

A novel non-wear algorithm using to improve accuracy of activity estimates from accelerometry

Introduction: Accelerometry is commonly used to quantify physical activity and sedentary behaviour. Accurate detection of sensor removal is important to ensure non-wear periods are not misrepresented as sedentary behaviour or sleep. Current non-wear algorithms assess parameters including bout duration and temperature that lead to undetected non-wear periods and overestimated sedentary time. This work aimed to improve the accuracy of existing non-wear algorithms. Methods Data were collected from 39 participants through the Ontario Neurodegenerative Disease Research Initiative who wore a wrist biosensor continuously for 7-days as part of a multi-sensor collection. Absolute and rate-of-change of near-body temperature, and standard deviation of the acceleration signal were used to train a decision tree classifier (depth 3, cross-validation 10) on 10 participants to detect non-wear start and stop times (5-minute minimum duration). Algorithm performance was compared to two commonly reported algorithms (1, 2) on the remaining data (n = 29) using a ‘gold standard’ visually-inspected dataset. The algorithm was evaluated using precision, recall, accuracy and F1-score. Results: The current algorithm exceeded performance metrics of both comparator algorithms: Precision Recall F1-score  Accuracy Current 0.77 0.92 0.84 0.99 Zhou (1) 0.52 0.83 0.64 0.97 Van Hees (2) 0.58 0.61 0.59 0.97 Discussion: The addition of a temperature rate-of-change threshold and focus on start and stop times improved non-wear detection. Performance outcomes existed for 5–minute minimum bout durations, which also has important implications for accurately detecting real-life non-wear events and improving activity estimates.

Individual differences in lifestyle factors and the effects of an acute exercise intervention on executive functioning in children and youth with ADHD

Attention-Deficit Hyperactivity Disorder (ADHD) is a prevalent neurodevelopmental disorder among children and youth. Individuals with ADHD typically experience executive functioning deficits that negatively impact their working memory, inhibitory control, and task-switching. Exercise interventions have been identified as a potential supplemental treatment to help ameliorate ADHD symptomology. Research has demonstrated that exercise interventions can enhance executive functioning among children and youth with ADHD. However, little to no research has investigated how individual differences in lifestyle factors may impact a child's reactivity to acute exercise interventions. The current study focused on the role of three individual difference factors (medication status, physical fitness level, physical activity behaviours), and how they impact the relationship between acute exercise and executive functioning in children and youth with ADHD. Participants diagnosed with ADHD between the ages of 10-14 engaged in two sessions, an exercise session and a control session. During the exercise condition, participants completed a 10-minute bout of moderate-intensity stationary biking in addition to a pre-post battery of executive functioning assessments. The control condition consisted of 10-minutes of silent reading. Following a 10-minute bout of exercise, we found that regardless of medication status, physical fitness level, or physical activity behaviours, all individuals performed similarly well on each measure of executive functioning. Despite similar performance across groups, the pattern of data suggests that physical fitness level may impact the relationship between acute exercise and executive functioning among children and youth with ADHD. However, further research with a greater sample size is needed to fully unravel this issue.