Browsing by Author "Mang, Cameron"

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Open Access
Cardiac cycle timing intervals in acute COVID-19 and recovered COVID-19 with sustained symptoms
(Faculty of Graduate Studies and Research, University of Regina, 2022-06) Singh, Jyotpal; Neary, Patrick; Bardutz, Holly; Bhagaloo, Lanishen; Mang, Cameron; Buttigieg, Josef; Eves, Neil D.
Research is available to show that COVID-19 can result in both acute and sustained cardiac damage. Acute cardiac damage may be due to elevated inflammatory responses and can result in ischemia, which can lead to impairments in the cardiac cycle timing events. The purpose of this project was threefold: 1) to characterise cardiac cycle timing intervals in patients with COVID-19, 2) to understand the mechanisms that compromise cardiac function in post-acute COVID-19 syndrome (PACS)/long COVID, and 3) to identify unique cardiac dysfunction which can occur due to COVID-19 as compared to cardiac and respiratory disease. First, case studies showed that daily observation of cardiac function provided detailed information about the overall dynamic changes by which cardiac dysfunction occurs, and thus can be beneficial study on a case by-case basis, day-to-day during acute infection. The literature review supports the findings of altered cardiac mechanics and suggests that right ventricular dysfunction, along with global longitudinal strain and diastolic dysfunction are common findings in patients with PACS/long COVID, and a more severe acute myocardial injury during the index hospitalization appears to exacerbate cardiac function on follow-up. Finally, a Kruskal-Wallis ANOVA showed that participants with COVID-19 and sustained symptoms present with elevated systolic time and decreased IVCT in comparison to acute COVID-19, and those with respiratory and cardiac disease. These are reflected by decreases in heart, diastolic, and systolic performance indices (HPI, DPI and SPI, respectively), thereby showcasing a unique cardiac dysfunction in patients with sustained symptoms from COVID-19. Future research must consider the details of cardiac complications during the acute infection period and relate this to the cardiac function in patients with long COVID during a mid- and long-term follow-up.
Open Access
The effect of relapsing-remitting Multiple Sclerosis on gait variability and regularity
(Faculty of Graduate Studies and Research, University of Regina, 2022-10) Kohrs, Russell Alexander; Barden, John; Bruno, Paul; Mang, Cameron; Donkers, Sarah
Multiple Sclerosis (MS) is an inflammatory and neurodegenerative autoimmune disease that destroys the myelin sheath of the central nervous system. Gait impairments are one of the most debilitating and concerning symptoms for PwMS that can significantly impact an individual’s quality of life. Gait changes in people with MS (PwMS) have often been quantified using basic spatiotemporal parameters; however, research into more complex measures of gait variability, such as the measurement of small fluctuations that occur during the gait cycle (e.g., fractal-scaling index (FSI)), and the measurement of the consistency of trunk-based acceleration waveforms (gait regularity), have been shown to provide deeper insights into gait deficits in other neurological conditions. This research has demonstrated the potential to provide better predictors for important clinical factors such as fall risk. The purpose of this study was to investigate the relationship between the aspects of gait variability and regularity in people with relapsing-remitting MS and to compare the results to a healthy, age- and sex-matched control group. Using a cross-sectional study design, thirty participants were recruited (13 MS (12F; 44.9 ± 14.0 years; Median EDSS (IQR): 2.5 (2.0 – 4.5)); 17 controls (15F; 40.3 ± 10.9 years). Each participant completed a ten-minute walking test at a self-selected speed around a 200m track. Gait patterns were assessed using a tri-axial accelerometer placed on the lower back. From the raw accelerometer data, gait variability was assessed as the coefficient of variation (COV) of step time and stride time, step regularity and stride regularity, and the FSI of stride time. PwMS were found to walk with significantly higher step time COV and lower anteroposterior (AP) step regularity and AP and mediolateral (ML) stride regularity than the control group. PwMS were also found to walk significantly slower and take shorter steps than the control group. Strong associations between the differences in speed and gait variability were also found. This association appeared to produce a powerful combined effect on the locomotor function of PwMS, but gait speed also appeared to partially influence the significant differences seen in gait regularity. The findings of this study suggest that PwMS walk with a significant amount of variability and demonstrate greater bilateral asymmetry and impairment of movement consistency during the braking and propulsive phases of gait than healthy controls. Future research is needed to better understand the relationship between MS, gait speed and measures of gait variability.
Open Access
The effects of chronic stress on allocentric versus egocentric spatial memory
(Faculty of Graduate Studies and Research, University of Regina, 2023-03) Ziemer, Julie Lianne; Sykes Tottenham, Laurie; Gordon, Jennifer; Sharpe, Donald; Mang, Cameron
Spatial navigation is a skill that is critically dependent upon an organism’s ability to remember object locations and orient themselves in an environment. Two strategies commonly examined in spatial memory research are allocentric (ALLO) and egocentric (EGO). Individuals using an ALLO strategy orient with respect to a cognitive map of distal environmental boundaries, while those using an EGO strategy orient with respect to themselves and singular proximal landmark cues. Stress affects spatial memory, but it is unclear whether one strategy more than the other enhances processing in the context of chronic stress. The present study examined the effects of chronic stress on ALLO and EGO spatial memory. A final sample of forty-two male participants completed a chronic stress measure and then a spatial memory dual-strategy navigation task with ALLO and EGO cues. Participants’ preferred strategy was determined by identifying which strategy they relied upon to guess the previously viewed location of an invisible target. Participants’ EGO and ALLO performance was determined by examining how accurate their guesses were on trials for which only one cue type was an accurate predictor. Chronic stress variables (frequency and severity) from chronic stressors that occurred during childhood as well as overall chronic stress were examined as potential predictors of visuospatial strategy performance in a series of regression analyses. Regression analyses were also used to examine chronic stress variables (frequency and severity) from chronic stressors that occurred during childhood as well as overall chronic stress as potential predictors of strategy preference scores. A greater number of chronic stress events was associated with a greater preference for EGO strategy use, but no relationships were found when examining chronic stress severity, performance, and childhood chronic stressors. The findings suggest that chronic stress—specifically overall chronic stress—may be an important factor related to visuospatial memory preference.
Open Access
The Effects of Creatine Monohydrate Supplementation and Resistance Training in Stroke Survivors
(Faculty of Graduate Studies and Research, University of Regina, 2020-06) Butchart, Sara Marie; Candow, Darren; Mang, Cameron; Forbes, Scott; Ditor, David
The purpose was to investigate the effects of progressive resistance training and creatine supplementation in individuals’ post-stroke. Participants were randomized to one of two groups: creatine (n = 5; 51 ± 15 yrs, 173.04 ± 10.75 cm, 84.74 ± 19.24 kg) or placebo (n = 3; 73 ± 8 yrs, 171.26 ± 5.31 cm, 73.33 ± 5.83 kg) during 10 weeks of supervised, progressive resistance training. Prior to and following training and supplementation, assessments were made for body composition (lean tissue, fat mass, bone mineral; dual energy x-ray absorptiometry), muscle thickness (elbow and knee flexors and extensors; ultrasound), muscle strength (1-repetition maximum leg-press, chest-press), tasks of functionality (berg balance scale, six-minute walk test), cognition (Montreal Cognitive Assessment), and symptoms of anxiety (Generalized Anxiety Disorder Assessment) and depression (Center for Epidemiological Studies Depression Scale). The creatine group experienced a significant increase (p < 0.05) in leg press (pre 170 ± 62 kg, post 230 ± 82 kg) and chest press strength (pre 51 ± 34 kg, post 74 ± 45 kg), muscle thickness of the elbow flexors (left side: pre 3.31 ± 0.68 cm, post 3.65 ± 0.53 cm; right side: 3.08 ± 0.52 cm, post 3.56 ± 0.70 cm), 6-minute walking performance (pre 598.80 ± 168.92 sec, post 638.00 ± 160.15 sec) and a decrease in anxiety over time (pre 4.80 ± 3.83, post 1.40 ± 1.51). There were no changes in the placebo group for any variable. In conclusion, creatine monohydrate supplementation and progressive resistance training is an effective lifestyle intervention for improving strength, muscle thickness, walking performance and decreasing anxiety in a very small cohort of stroke survivors.
Open Access
Exercise Effects on Consolidation of Speech Training in Post Stroke Aphasia: A Case Series Study
(2024-11-06) Hebert, Taylor; Bardutz, Holly; Mang, Cameron
Open Access
An exploratory consideration of cognition and physiology in athletes following concussion
(Faculty of Graduate Studies and Research, University of Regina, 2023-03) Lillie, Garrett Richard; Dorsch, Kim; Neary, Patrick; Mang, Cameron; Brigham, Mark
A mild traumatic brain injury (mTBI), colloquially known as a concussion, is an injury of the brain that often results in significant functional impairment for days, weeks, or even months. While the most common symptoms of concussion have been well documented and studies frequently note a deficit in either higher-level cognitive functioning and autonomic physiological control, there is a lack of research describing the effect of concussion on executive functioning and heart rate variability (HRV). The aim of this study was to address gaps in literature by describing changes in an individual’s executive functioning and physiology simultaneously following a concussion using two investigative approaches, using the theory of neurovisceral integration as a guiding framework. Secondary data from University of Regina athletes was used to examine baseline executive functioning (measured by Neurotracker®) and athlete HRV transformed from ECG. These results were subsequently compared to the same measures postinjury. Prior to review of data from the 2019-2020 academic year, there was an expectation that occurrence of a concussion would be associated with a decrease in Neurotracker® performance, Mean R-R intervals (Mean R-R), and Root-Mean-Square-Difference of successive R-R intervals (RMSSD) while also being associated with increases in Low-Frequency/High-Frequency (LF/HF) ratio and Standard Deviation 2/Standard Deviation 1 (SD2/SD1) ratios. Across a sample of eight participants, only one participant experienced the expected change in variable while the two participants that experienced symptoms the longest, featured smaller deviations from their baselines. My study was exploratory in nature and suggests directions for future research.
Open Access
Long-term Effects of Concussions on Cerebral Autoregulatory Mechanisms in Retired Contact Sport Athletes
(Faculty of Graduate Studies and Research, University of Regina, 2020-06) Sirant, Luke WIlliam; Neary, Patrick; Candow, Darren; Mang, Cameron; Wukker, Barrt
Increase in public awareness of the immediate effects of concussions has fueled researchers to better understand the injury from both a clinical and physiological standpoint in hopes to improve preventative and rehabilitation practices. However, there is very little information regarding the long-term change in the physiological systems in individuals with a history of previous concussions. Therefore, the purpose of this thesis was to explore how multiple concussions effected cerebral haemodynamics in the three major cerebral autoregulatory mechanisms in retired contact sport athletes. Specifically, three studies were conducted to focus on the different cerebral autoregulatory control mechanism. Study one (Chapter 3) focused on the neurovascular coupling mechanism (NVC), study two (Chapter 4) focused on cerebrovascular reactivity (CVR), and study three (Chapter 5) focused on dynamic cerebral autoregulation (dCA). 55 retired contact sport athletes, between the ages of 40-80 years of age (mean=59±8 yr), with a history of previous concussions were recruited with 29 non-contact athletes (mean =64±8 yr), with no history of concussion recruited as a control group. All participants underwent physiological testing using non-invasive near-infrared spectroscopy (NIRS). Each of the three protocols began with 5-minute of seated rest to determine physiological baselines. NVC was assessed using a 5-minute (20-second eyes closed:40-second eyes open x 5 repeats) object identification protocol (“Where’s Waldo”), CVR was assessed with a 5-minute hypercapnic challenge (20-second breath-hold:40-second normal breathing x 5 repeats), and dCA was assessed with a 5-minute squat-stand baroreflex maneuver (10-second squat:10-second stand; 0.05 Hz frequency). Results showed significant differences in all three mechanisms, primarily in the left prefrontal cortex between the previously concussed group (mTBI) and the healthy controls (CTRL). Similar increases were observed in HbDiff ΔMAX and O2Hb ΔMAX in the assessment of CVR and dCA but not seen in NVC. These findings provide evidence that there are autonomic nervous system dysregulation occurring in individuals with a history of multiple concussions due to evidence that cerebral autoregulation is impaired in all three autoregulatory mechanisms.
Open Access
Measures of Cardioautonomic Dysfunction as Markers of Sport Related Concussion
(Faculty of Graduate Studies and Research, University of Regina, 2020-12) Teckchandani, Taylor Arjun; Neary, Patrick; Candow, Darren; Mang, Cameron; Brigham, Mark
The field of concussion research is vast but lacking in uniformity when implementing or recommending evaluative protocols. Of the pathological characteristics associated with concussion, autonomic dysfunction includes but is not limited to a dysregulation of autonomic afferent and efferent pathways in both cortical and medullary regions, resulting in impaired intrinsic autoregulatory function influencing inotropic and chronotropic aspects of myocardial contractility, as well as vascular smooth muscle regulation (1,2). Popular methods of assessing autonomic function in the wake of a concussion include heart rate variability (HRV) analysis, blood pressure variability analysis (BPV), and spontaneous baroreceptor sensitivity (SBRS). This project aims to examine the impact of concussive trauma on cardioautonomic functioning and multilevel cardioautonomic integration across two studies in 65 otherwise healthy college-aged athletes, with a focus on heart rate variability, blood pressure variability, and the multilevel autonomic integration required for cardiac baroreflex functioning across six time epochs (baseline, days 1-3, days 4-7, days 8-11, days 12-15, and days 16+) using rest and rhythmic breathing portions (0.1 Hz) of the Neary Protocol. Two within-subject repeated-measures multilevel modelling approaches were used for statistical analysis to address non-equidistant sampling intervals present in the data set, with a Sidak post-hoc test for pairwise comparisons with alpha set at p<0.05. I conclude that rhythmic breathing is the preferred methodology to assess cardioautonomic dysfunction in the wake of a concussion, integrate heart rate variability and baroreceptor sensitivity values, and speculate about a potential mechanism responsible for patterns of cardioautonomic dysfunction to paint a picture of the multilevel autonomic integration that can be readily evaluated to diagnose concussion.
Open Access
Participation in 12 weeks of the Saskatchewan Health Authority’s Diabetes Wellness Series: Effects on appetite hormone response to a mixed meal tolerance test
(Faculty of Graduate Studies and Research, University of Regina, 2024-07) Nafisi, Raha; Totosy, Julia; Bomhof, Marc; Mang, Cameron
Food intake (FI) dysregulation in type 2 diabetes (T2D) may be due to impaired tonic satiety signals (e.g., insulin, leptin) and episodic FI signals (e.g., glucose, acyl-ghrelin [a-ghrelin; appetite-stimulating], active glucagon-like peptide-1 [aGLP-1; appetite-inhibiting]), promoting caloric overconsumption. Research has shown that regular physical activity is associated with more sensitive appetite control. The present thesis aimed to: (1) investigate the acute responsiveness of FI regulatory signals (glucose, insulin, a-ghrelin, aGLP-1) and perception of appetite to a 120-minute mixed meal tolerance test (MMTT) in individuals with T2D, and (2) assess the impact of participation in 12 weeks of the Saskatchewan Health Authority’s (SHA) Diabetes Wellness Series (DWS) program, incorporating exercise (aerobic and resistance) and education (e.g., nutrition, mental health, stress, etc.), on FI regulatory signal responsiveness and perception of appetite to an MMTT. Data from 21 participants (9M, 12F; age = 68.0±9.8 y; duration of T2D diagnosis = 11.0±10.7 y) was collected for Objective 1; values for blood glucose (6.4±1.7, 7.5±2.2, 8.8±2.2, 9.5±2.6, 9.6±3.1, 8.4±3.0mmol/L), a-ghrelin (251.9±198.5, 189.3±147.5, 151.1±124.7, 159.1±147.7, 129.3±113.2, 213.4±193.5pg/ml), aGLP-1(1.1±1.1, 3.0±2.6, 3.4±4.0, 1.8±1.6, 1.7±2.5, 1.5±1.3 pM), insulin (19.3±9.1, 28.5±19.4, 40.7±31.9, 56.6±40.9, 47.9±33.2, 36.9±28.6 ulU/mL), and average appetite (AA; via visual analog scale) (47.7±22.2, 38.6±23.2, 38.7±19.2, 36.1±17.1, 46.4±20.0, 51.5±16.7 mm) were observed before, and at 15, 30, 60, 90, and 120-mintute after consuming a 237g Boost® (240kcal [56.4% carbohydrate, 24.9% protein, and 18.7% fat]). Repeated measures General Linear Model (GLM) analyses revealed a significant effect of time for all FI regulatory signals and perception of appetite (p<0.05). Compared to the literature on metabolically healthy adults, fasted values of a-ghrelin were low while fasted values of glucose, insulin, leptin, and aGLP-1 were high, and there was an impaired responsiveness to the MMTT. No relationship between FI regulatory signals and AA suggests a disrupted association between FI signals and perception of appetite in T2D. Sixteen participants (7M, 9F; age = 69.0±11.0 y; duration of T2D diagnosis = 11.0±10.3 y) returned after the 12-weeks of SHA DWS programming. Factorial repeated GLM analyses assessed main effects of training state (pre vs. post) and time (0, 15, 30, 60, 90, 120 minutes) and their interactions; no interactions or main effects of training-state were found; however, a main effect of time was observed for all FI regulatory signals and perception of appetite (p<0.05). Incremental area under the curve (iAUC) analyses showed increased aGLP-1 (p=0.03) and a trend towards decreased a-ghrelin (p=0.07). The hormone ‘sensitivity’ did not change at post-intervention; however, no significant change in the relationships between FI regulatory signals and AA were observed. While 12 weeks of adherence to the SHA DWS had a positive influence on some aspects of FI regulation, it may not have been enough to elicit clinically significant changes. The DWS should continue to be promoted to expose individuals with T2D to exercise programming and education; however, extending the program duration beyond 12 weeks to allow more time for habit formation (i.e., positive lifestyle change), introducing more intensive and frequent exercise sessions, and adopting a more focused approach to nutrition and dietary changes may be necessary to enhance the effectiveness of the DWS. Further, future directions to address the high incidence and prevalence of T2D in Saskatchewan should include prevention in addition to management.
Open Access
The relationship between neurocognitive performance and sport-related musculoskeletal injury
(Faculty of Graduate Studies and Research, University of Regina, 2022-08) O'Neill, Erica M.B.; Bruno, Paul; Dorsch, Kim; Mang, Cameron; Lebrun, Constance
Background: The number of sport-related musculoskeletal (MSK) injuries continues to rise even with an increase in prevention programs. The potential relationship between neurocognitive performance and sport-related MSK injury has begun to emerge in the literature, with results suggesting that athletes with lower baseline neurocognition sustain more injuries compared to those with higher baseline neurocognition. Purpose: This study aims to build on the previous literature by investigating this relationship while controlling for variables that have been well-documented as predisposing factors for injury (i.e., previous MSK and brain injury). Methods: A total of 87 participants from the University of Regina Rams football team were included in the study. Baseline Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) data (Verbal Memory Composite, Visual Memory Composite, Visual Motor Speed Composite, Reaction Time Composite, and Impulse Control Composite), MSK injury history, concussion history, and number of games participated were all gathered. Acute lower extremity (LE) MSK injuries that occurred over the course of the six-game, 11-week season were recorded and included in the analysis. Two statistical analyses were conducted: linear and logistic regression. Both regression analyses used a hierarchical method with step 1 including independent variables of previous LE MSK injury and previous concussion history. Step 2 involved the addition of the number of games played as an independent variable and step 3 involved the addition of all neurocognition measures as independent variables (Verbal Memory, Visual Memory, Visual Motor, Reaction Time, and Impulse Control). The dependent variable for the linear regression was the severity of injury, measured as the number of days from time of injury to full return to sport with no restrictions. The dependent variable for the logistic regression was injury versus no injury. Results: Sixteen (18.4%) of the participants suffered an injury over the course of the season, with the average (standard deviation [SD]) injury severity being 3.77 (10.24) days. Step 2 (number of games played) had the largest impact on both regression models. Having played 1-2 games in the six-game season was the only independent variable to make a statistically significant contribution to predicting injury severity (β = .338, p = .005) and injury occurrence (OR [95%CI] = 19.880 [2.239, 176.477], Wald = 7.202, p = .007). The final logistic regression model correctly classified 18.8% of injured participants and 98.6% of non-injured participants. Conclusion: Playing in 1-2 games in a six-game season was the only statistically significant independent variable at predicting both musculoskeletal injury occurrence and severity. There are several limitations to this study affecting the generalizability of the results. The assumptions of linearity, homoscedasticity, and normality were not met in the data, and there was a small number of injuries due to the small sample size and short follow-up period. More research is needed in this area, particularly involving other populations outside of collegiate level football athletes, longer study periods, and the potential relationship between executive functioning and MSK injury.