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Restoring muscle function to patients with spinal cord injuries (SCIs) will invariably require a functioning lower motor neuron (LMN). As techniques such as nerve transfer surgery emerge, characterizing the extent of LMN damage associated with SCIs becomes clinically important. Current methods of LMN diagnosis have inherent limitations that could potentially be overcome by the development of magnetic resonance imaging (MRI) biomarkers: specific features on MRI that are indicative of LMN integrity. To identify research on MRI biomarkers of LMN damage in the acute phase after SCI, we searched PubMed, EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials for articles published from inception to April 27, 2021. Overall, 2 of 58 unique articles screened met our inclusion criteria, both of which were small studies. We therefore identify MRI biomarkers of LMN damage overlying SCI as a notable gap in the literature. Because of the lack of existing literature on this specific problem, we further our discussion by examining concepts explored in research characterizing MRI biomarkers of spinal cord and neuronal damage in different contexts that may provide value in future work to identify a biomarker for LMN damage in SCI. We conclude that MRI biomarkers of LMN damage in SCI is an underexplored, but promising, area of research as emerging, function-restoring therapies requiring this information continue to advance.

Spinal cord injury (SCI) results in severe cardiovascular dysfunction due to the disruption of supraspinal control. Autonomic dysreflexia (AD), an uncontrolled rise in blood pressure in response to peripheral stimuli including common bowel routine, digital anorectal stimulation (DARS), reduces the quality of life, and increases morbidity and mortality. Recently, spinal cord stimulation (SCS) has emerged as a potential intervention to mitigate unstable blood pressure following SCI. The objective of this case series was to test the real-time effect of epidural SCS (eSCS) at the lumbosacral spinal cord, the most common implant location, on mitigating AD in individuals with SCI. We recruited three individuals with cervical and upper thoracic motor-complete SCI who have an implanted epidural stimulator. We demonstrated that eSCS can reduce the elevation in blood pressure and prevent DARS-induced AD. The blood pressure variability analysis indicated that eSCS potentially reduced vascular sympathetic nervous system activity during DARS, compared to without eSCS. This case series provides evidence to support the use of eSCS to prevent AD episodes during routine bowel procedures, improving the quality of life for individuals with SCI and potentially reducing cardiovascular risks.

Background: People with spinal cord injuries (SCI) commonly experience pain and spasticity; limitations of current treatments have generated interest in cannabis as a possible therapy. Objectives: We conducted this systematic review to: 1) examine usage patterns and reasons for cannabinoid use, and 2) determine the treatment efficacy and safety of cannabinoid use in people with SCI. Methods: PubMed, Embase, Web of Science and Cumulative Index to Nursing and Allied Health Literature databases were queried for keywords related to SCI and cannabinoids. Results: 7,232 studies were screened, and 34 were included in this systematic review. Though 26 studies addressed cannabinoid usage, only 8 investigated its therapeutic potential on outcomes such as pain and spasticity. The most common method of use was smoking. Relief of pain, spasticity and recreation were the most common reasons for use. A statistically significant reduction of pain and spasticity was observed with cannabinoid use in 83% and 100% of experimental studies, respectively. However, on examination of randomized control trials (RCTs) alone, effect sizes ranged from - 0.82 to 0.83 for pain and -0.95 to 0.09 for spasticity. Cannabinoid use was associated with fatigue and cognitive deficits. Conclusion: Current evidence suggests that cannabinoids may reduce pain and spasticity in people with SCI, but its effect magnitude and clinical significance are unclear. Existing information is lacking on optimal dosage, method of use, composition and concentration of compounds. Long-term, double-blind, RCTs, assessing a wider range of outcomes should be conducted to further understand the effects of cannabinoid use in people with SCI.

CONTEXT: Autonomic dysreflexia (AD), characterized by a transient increase in systolic blood pressure (BP), is experienced by individuals with spinal cord injury (SCI) and can be purposefully induced (‘boosting’) to counteract autonomic dysfunction that impairs cardiovascular responses to exercise. Herein, we demonstrate the impact of unintentional boosting observed during cardiopulmonary exercise testing (CPET) in an inactive male with SCI (C5, motor-complete). FINDINGS: On two separate occasions the individual performed a standard arm-crank CPET (1-min stages, 7W increase in resistance) following by a longer CPET (4-min stages, 12W increase in resistance), both to volitional exhaustion. The second CPET was performed to confirm the accuracy of exercise intensity prescription and verify peak exercise parameters. Immediately following the second CPET on the initial visit, the individual reported symptoms of AD, verified as a 58mmHg increase in systolic BP from baseline. Relative to the first CPET, performed only 35 min earlier, there were pronounced differences in peak exercise responses. In comparison to the longer CPET performed on the second visit without a concomitant episode of AD (thereby controlling for the type of CPET protocol administered), peak exercise outcomes were considerably elevated: power output (Δ19W), oxygen uptake (Δ3.61 ml·( )kg·(−1)min(−1)), ventilation (Δ11.4 L ·min(−1)) and heart rate (Δ9 b·min(−1)). CONCLUSION/CLINICAL RELEVANCE: This case raises important considerations around the nuances of CPET in this population. In individuals susceptible to BP instability, the physiologically boosted state may explain a significant proportion of the variance in peak aerobic capacity and should be closely monitored before and after clinical CPET.

Cervical and upper-thoracic spinal cord injury (SCI) commonly results in autonomic cardiovascular impairments. These impairments can lead to alterations in blood flow, cerebral perfusion pressure and ultimately tissue perfusion, which can lead to an elevated risk of stroke and global cognitive deficits. The aim of this study was to assess cerebrovascular reactivity (CVR) in both the grey matter (GM) and brainstem using functional magnetic resonance imaging (fMRI) in participants with SCI compared to non-injured controls. CVR represents the capacity of brain parenchyma to change cerebral blood flow in response to a vasoactive stimulus (e.g. carbon dioxide, CO2) or altered metabolic demand [e.g. neurovascular coupling (NVC)]. Thirteen participants (7 chronic SCI (all male, median age of 42 years), 6 controls (all male, median age of 33 years) were studied cross-sectionally. CVR was measured by assessing the MRI-blood oxygen level–dependent signal with hypercapnic challenge (controlled CO2 inhalation). The CVR outcome measure was assessed in three ways. Initially, CVR was calculated as is standard, via the linear, least-squares fit across the whole gas challenge protocol (CVRwhole). In addition, CVR was further decomposed into its dynamic (tau) and static components (steady state CVR; ssCVR). A 24-hour ambulatory blood pressure monitor was worn to capture free-living blood pressure outcomes. Our results showed a longer tau in the GM of SCI participants compared to controls (median of the difference = 3.0 seconds; pS=-0.77, p=0.041 and RS=-0.76, p=0.049, respectively, where RS is the Spearman’s rank Correlation Coefficient. Neurological level of injury (NLI), modified into an ascending, continuous numeric variable, was positively correlated with GM CVRwhole (RS=0.85, p=0.016), GM ssCVR (RS=0.95, p=0.001) and brainstem ssCVR (RS=0.90, p=0.006). Lower CVRwhole and ssCVR in the SCI-cohort was significantly (PS≥ 0.81) and a higher frequency of hypotensive episodes (RS≥ -0.83). Thus, living with a SCI for a longer period of time, having a higher NLI and lower blood pressure are linked with poorer CVR outcomes. Our preliminary findings reveal an important difference between the cohorts in the dynamic CVR component, tau. Collectively, these results may partially explain the increased cerebrovascular health burden in individuals with SCI.HighlightsCVR is the change in blood flow in response to a vasodilatory stimulus (e.g., hypercapnia).Impaired CVR is linked with increased stroke risk and cognitive deficits.We investigated the dynamic and steady-state components of CVR using fMRI in individuals with a SCI.The dynamic component was significantly different compared to non-injured controls.CVR is significantly correlated with time since injury, level of injury and ambulatory daytime blood pressure.

The most common non-pharmacological intervention for both peripheral and cerebral vascular health is regular physical activity (e.g., exercise training), which improves function across a range of exercise intensities and modalities. Numerous non-exercising approaches have also been suggested to improved vascular function, including repeated ischemic preconditioning (IPC); heat therapy such as hot water bathing and sauna; and pneumatic compression. Chronic adaptive responses have been observed across a number of these approaches, yet the precise mechanisms that underlie these effects in humans are not fully understood. Acute increases in blood flow and circulating signalling factors that induce responses in endothelial function are likely to be key moderators driving these adaptations. While the impact on circulating factors and environmental mechanisms for adaptation may vary between approaches, in essence, they all centre around acutely elevating blood flow throughout the circulation and stimulating improved endothelium-dependent vascular function and ultimately vascular health. Here, we review our current understanding of the mechanisms driving endothelial adaptation to repeated exposure to elevated blood flow, and the interplay between this response and changes in circulating factors. In addition, we will consider the limitations in our current knowledge base and how these may be best addressed through the selection of more physiologically relevant experimental models and research. Ultimately, improving our understanding of the unique impact that non-pharmacological interventions have on the vasculature will allow us to develop superior strategies to tackle declining vascular function across the lifespan, prevent avoidable vascular-related disease, and alleviate dependency on drug-based interventions.

OBJECTIVES: This case-series investigated energy expenditure, cardiovascular responses, and psychosocial outcomes during two wheelchair dancing routines with different tempos. METHODS: Three individuals with chronic, non-traumatic spinal cord injuries [males, mean age 42 (13) years, C3-T12, AIS D, schwannoma=1, poliomyelitis=1, ependymoma=1] performed slow (rumba, 80 bpm) and fast (salsa, 170 bpm) wheelchair dance routines. Physiological [heart rate, blood pressure, relative oxygen consumption (VO2), metabolic task equivalent] and psychosocial parameters [ratings of perceived exertion, enjoyment and Brunel Mood Score] were measured pre, during, and post-dancing. RESULTS: All participants showed an elevation in heart rate and relative VO2 from rest to dancing with a subsequent decrease in these parameters post-dance for both routines. Relative to the slow dance routine, two out of three participants demonstrated greater heart rate, relative VO2, ratings of perceived exertion, and enjoyment during the fast dance routine. For all three participants, metabolic task equivalents ranged from 1.7–2.4 (slow) and 2.1–3.8 (fast), suggesting the intervention was of light to moderate intensity for slow and fast dance routines, respectively. Enjoyment ratings ranged from “quite a bit” to “extremely.” No differences in Brunel mood subscales were observed. CONCLUSION: This case-series offers a preliminary understanding of the acute cardiometabolic and psychosocial responses to wheelchair dance routines of differing intensities performed by individuals with spinal cord injury. Responsiveness observed among these participants suggests the potential use of wheelchair dance for promoting physical activity and improving psychological well-being.

To review the evidence regarding the most common practices adopted with cardiopulmonary exercise testing (CPET) in individuals with spinal cord injury (SCI), with the following specific aims to: (1) determine the most common averaging strategies of peak oxygen uptake (V̇OSearches for this scoping review were conducted in MEDLINE (PubMed), EMBASE, and Web Science.Studies were included if (1) were original research on humans published in English, (2) recruited adults with traumatic and non-traumatic SCI, and (3) V̇OExtracted data included authors, journal name, publication year, participant characteristics, and comprehensive information relevant to CPET.We extracted data from a total of 200 studies involving 4,928 participants. We found that more than 50% of studies adopted a 30-sec averaging strategy. A wide range of endpoint criteria were used to confirm the attainment of maximal effort. In the convenience sample of individuals with SCI (n=30), the mean V̇OThe adoption of accepted and standardized methods for processing and analyzing CPET data is needed to ensure high-quality, reproducible research, and inform population-specific normative values for individuals with SCI.

Objective: To determine the effects of exercise on individual cardiometabolic syndrome (CMS) risk factors in adults with chronic spinal cord injury (SCI). Data Sources: English language searches of PubMed, Web of Science, EMBASE, and Scopus (January 1, 1970, to July 31, 2019). Study Selection: Articles were included if they met the following criteria: (1) original articles with statistical analysis, (2) participants were adults with a SCI sustained ≥1 year ago, (3) exercise intervention duration ≥2 weeks, and (4) included any CMS risk factor as an outcome. Data Extraction: The methodological quality of articles was assessed using the Downs and Black score. Data Synthesis: Sixty-five studies were included for the final analysis, including 9 studies classified as high quality (≥66.7%), 35 studies classified as fair quality (50%-66.6%), and 21 studies classified as low quality (75% maximum heart rate) appears to improve waist circumference and hepatic insulin sensitivity but appears insufficient for improving fasting glucose, lipid profile, or resting blood pressure. The addition of RT to upper body aerobic exercise may elicit favorable changes in the lipid profile. More high-quality studies are needed to confirm if FES cycling is effective at improving peripheral insulin sensitivity.

Study design Cross-sectional. Objective It is known that left ventricular mass (LVM) and cardiorespiratory fitness (CRF) are associated to fat-free mass (FFM). It is unknown if these factors associated with left ventricular (LV) structure and function outcomes in individuals with spinal cord injury (SCI). Setting University-based laboratory.Vancouver, BC, Canada. Methods Thirty-two individuals (aged 40 ± 11 years) with chronic, motor-complete SCI between the fourth cervical and sixth thoracic levels were recruited. Echocardiographic LV parameters and body composition were assessed at rest, as per the recommended guidelines for each technique. CRF was assessed during an incremental arm-cycle exercise test until volitional fatigue. The appropriate bivariate correlation coefficients [i.e., Pearson’s (r) and Spearman’s rank (Rs)] tests were used for normal and non-normal distributed variables, respectively. Results LV structure and function parameters were not associated with the indexed peak oxygen consumption (V̇O2peak) [i.e., relative to body weight or FFM] (Rs values ranged from −0.168 to 0.134, all P values > 0.223). The association between peak oxygen pulse and the resting echocardiographic-obtained SV was medium sized (Rs = 0.331, P = 0.069). The LVM associations with FFM and fat mass (FM) were large and small (r = 0.614, P r = 0.266, P = 0.141, respectively). Associations of absolute V̇O2peak were medium- positive with FFM (Rs = 0.414, P = 0.021) but negative with FM (Rs = −0.332, P = 0.068). Conclusion LV parameters measured at rest are not associated with V̇O2peak in individuals with cervical and upper-thoracic SCI. Given the observed associations between LVM and V̇O2peak with FFM, future studies may consider utilizing FFM for indexing cardiovascular measures following SCI.

Study design Cross-sectional construct validation study. Objectives To test the construct validity of the Leisure Time Physical Activity Questionnaire for People with Spinal Cord Injury (LTPAQ-SCI) by examining associations between the scale responses and cardiorespiratory fitness (CRF) in a sample of adults living with spinal cord injury (SCI). Setting Three university-based laboratories in Canada. Methods Participants were 39 adults (74% male; M age: 42 ± 11 years) with SCI who completed the LTPAQ-SCI and a graded exercise test to volitional exhaustion using an arm-crank ergometer. One-tailed Pearson's correlation coefficients were computed to examine the association between the LTPAQ-SCI measures of mild-, moderate-, heavy-intensity and total minutes per week of LTPA and CRF (peak volume of oxygen consumption [VO2peak] and peak power output [POpeak]). Results Minutes per week of mild-, moderate- and heavy-intensity LTPA and total LTPA were all positively correlated with VO2peak. The correlation between minutes per week of mild intensity LTPA and VO2peak was small-medium (r = 0.231, p = 0.079) while all other correlations were medium-large (rs ranged from 0.276 to 0.443, ps 0.05), except for a medium-sized correlation between heavy-intensity LTPA and POpeak (r = 0.294, p = 0.035). Conclusions People with SCI who report higher levels of LTPA on the LTPAQ-SCI also demonstrate greater levels of CRF, with stronger associations between moderate- and heavy-intensity LTPA and CRF than between mild-intensity LTPA and CRF. These results provide further support for the construct validity of the LTPAQ-SCI as a measure of LTPA among people with SCI.

To describe the status of spinal cord stimulation (SCS) research for the improvement of motor, sensory, and autonomic function for individuals living with a spinal cord injury (SCI).This scoping review identified original research published before March 31, 2021, via literature searches using MEDLINE, Embase, PubMed, Science Direct, Cumulative Index to Nursing and Allied Health, Sport Discus, and Web of Science, as well as a targeted search for well-known principal investigators. Search terms included permutations of "spinal cord stimulation," "epidural spinal cord stimulation," "transcutaneous spinal cord stimulation," "magnetic spinal cord stimulation," and "neuromodulation."Studies were included if they (1) were in English, (2) presented original research on humans living with a SCI, and (3) investigated at least 1 of the 3 forms of SCS.Extracted data included authors, publication year, participant characteristics, purpose, study design, stimulation (device, location, parameters), primary outcomes, and adverse events.As a scoping review the extracted data were tabulated and presented descriptively. Themes and gaps in the literature were identified and reported. Of the 5754 articles screened, 103 articles were included (55 epidural, 36 transcutaneous, 12 magnetic). The primary research design was a case study or series with only a single randomized controlled trial. Motor recovery was the most common primary outcome for epidural and transcutaneous SCS studies, whereas bowel and bladder outcomes were most common for magnetic SCS studies. Seventy percent of the studies included 10 or fewer participants, and 18 articles documented at least 1 adverse event. Incomplete stimulation parameter descriptions were noted across many studies. No articles mentioned direct engagement of consumers or advocacy groups.This review identified a need for more robust study designs, larger sample sizes, comparative studies, improved reporting of stimulation parameters, adverse event data, and alignment of outcomes with the priorities of the community with SCI.

Secondary data analysis.To characterize heart rate (HR) changes during autonomic dysreflexia (AD) in daily life for individuals with chronic spinal cord injury (SCI).University-based laboratory/community-based outpatient.Cardiovascular data, previously collected during a 24-h ambulatory surveillance period in individuals with chronic SCI, were assessed. Any systolic blood pressure (SBP) increase ≥20 mmHg from baseline was identified and categorized into confirmed AD (i.e., diarized trigger), unknown (i.e., no diary entry), or unlikely AD (i.e., potential exertion driven SBP increase) groups. SBP-associated HR changes were categorized as unchanged, increased or decreased compared to baseline.Forty-five individuals [8 females, median age and time since injury of 43 years (lower and upper quartiles 36-50) and 17 years (6-23), respectively], were included for analysis. Overall, 797 episodes of SBP increase above AD threshold were identified and classified as confirmed (n = 250, 31.4%), unknown (n = 472, 59.2%) or unlikely (n = 75, 9.4%). The median number of episodes per individual within the 24-h period was 13 (8-28). HR-decrease/increase ratio was 3:1 for confirmed and unknown, and 1.5:1 for unlikely episodes. HR changes resulting in brady-/tachycardia were 34.4%/2.8% for confirmed, 39.6%/3.4% unknown, and 26.7%/9.3% for unlikely episodes, respectively.Our findings suggest that the majority of confirmed AD episodes are associated with a HR decrease. Using wearable-sensors-derived measures of physical activity in future studies could provide a more detailed characterization of HR changes during AD and improve AD identification.

Coronavirus disease 2019 (COVID-19) can lead to considerable lung damage and even death. Less is known about the effects of COVID-19 on the cardiovascular system. In their recent JAMA Cardiology article, Shi and colleagues reported an association between cardiac injury and higher risk of in-hospital mortality in patients with COVID-19. Approximately 20% (82 patients) of the study cohort presented with a cardiac injury. The investigators identified cardiac injury as an independent risk factor of mortality during hospitalization (52% with cardiac injury vs. 5% without cardiac injury, p

A narrative review describing various components of sexual dysfunction in men with spinal cord injury (SCI), as well as addressing potential therapeutic approaches. Restoration of sexual function is considered one of the most important health priorities for individuals with SCI. The purpose of this review is to provide information regarding the factors that are less appreciated when considering changes to sexual function in men with SCI. We also propose therapeutic approaches, with a focus on lifestyle modifications, which have been shown to improve sexual function. A literature search was performed and limited evidence for therapeutic approaches in individuals with SCI was supplemented by consistent findings from the able-bodied population. We evaluated the less addressed factors known to contribute to sexual dysfunction in men with SCI, including hormonal influences (i.e., testosterone deficiency, thyroid hormone, and cortisol), psychological factors (i.e., pain, fatigue, depression, and body image), and secondary SCI complications (i.e., urinary tract infection, pressure sores, and autonomic dysreflexia). To address these factors beyond standard medical treatments for sexual dysfunction, options include physical activity/exercise, diet, and specific medications for symptom relief (i.e., testosterone replacement therapy and selective serotonin reuptake inhibitors for depression). Physical activity’s potential application, efficacy across multiple aspects of sexuality, and the lack of side effects, suggests that long-term exercise is a viable solution to directly or indirectly improve sexual function in males with SCI. Diet and supplemental medications may further promote body composition changes, which more broadly affect sexuality.

Background Following spinal cord injury (SCI), up to 64% of individuals experience cognitive deficit. However, the reliability of commonly used neuropsychological tests is currently unknown in this population. Objectives To evaluate the test-retest reliability of cognitive measures in individuals with SCI. Design Cross-sectional study. Setting Vancouver General Hospital. Participants Individuals with a chronic (>2 years) SCI (n = 22). Methods Across three visits (separated by ~16 days), 22 participants with chronic SCI completed a neuropsychological battery evaluating memory (Rey Auditory-Verbal Learning Test [RAVLT]), attention/concentration/psychomotor speed (Digit Span Task, Stroop Test), and executive function (Trail Making Test A&B, Symbol Digit Modalities Test, Controlled Oral Word Association Test). Coefficients of variation (CVintra ) and intraclass correlation coefficients (ICCs) were calculated to determine the reliability of each test between visits. Linear regressions were performed to assess the associations between variability (CVintra ) and participant characteristics, such as age or highest education level attained. Repeated-measures, one-way analysis of variance (ANOVA) was conducted to determine any significant practice effects, and smallest real differences (SRDs) were calculated. Main outcome measurements Repeated scores on aforementioned neuropsychological tests. Results ICCs ranged from 0.77 to 0.93, with the exception of RAVLT recognition score (ICC = 0.27). Age showed a moderate association with CVintra in RAVLT interference recall scores (r = 0.43, P = .047), but was not a confounding factor for other measures. Education was not associated with CVintra . Significant practice effects were noted for most of the cognitive tests assessed. Conclusions Other than the RAVLT recognition score, these cognitive measures demonstrated good-to-excellent reliability. Although this is encouraging, test-retest variability should be considered when interpreting the efficacy of various cognitive training strategies to mitigate cognitive decline in this population. Thus, the SRD values presented herein will allow researchers and clinicians to identify "true" changes in cognitive function with repeated testing. Level of evidence III.

ObjectiveTo characterize heart rate (HR) changes during autonomic dysreflexia (AD) in daily life for individuals with chronic spinal cord injury (SCI).DesignData analysis of two prospective clinical studies and one cross-sectional study.SettingSingle-center study.ParticipantsForty-five individuals (including 8 females) with a chronic SCI at or above the sixth thoracic spinal segment with confirmed AD, and a median age and time since injury of 43 years (interquartile range [IQR] 36 – 50) and 17 years (IQR 6 – 23) respectively, were included for analysis.InterventionsNot applicable.Main outcome measureAny systolic blood pressure (SBP) increase ≥ 20mmHg from baseline from a 24-hour ambulatory surveillance period was identified and categorized as either confirmed (i.e. known AD trigger), unknown (i.e. no diary entry), and unlikely (i.e. potential physical activity driven SBP increase). SBP-associated HR changes were categorized as either unchanged, increased or decreased compared to baseline.ResultsA total of 797 episodes of SBP increase above AD threshold were identified and classified as confirmed (n = 250, 31.4%), unknown (n = 472, 59.2%) or unlikely (n = 75, 9.4%). Median SBP changes and median SBP-related HR changes were 37 mmHg and -8 bpm, 28 mmHg and -6 bpm, or 30 mmHg and -4 bpm for confirmed, unknown, or unlikely episodes, respectively. HR-decrease/increase ratio was 3:1 for confirmed and unknown, and 1.5:1 for unlikely episodes. HR changes resulting in brady-/tachycardia were 34.4% / 2.8% for confirmed, 39.6% / 3.4% unknown, and 26.7% / 9.3% for unlikely episodes, respectively.ConclusionsOur findings suggest that the majority of confirmed AD episodes are associated with a HR decrease. Further improvements, such as more precise participant diaries combined with the use of 24-hour Holter electrocardiogram and wearable-sensors-derived measures of physical activity could provide a better, more detailed characterization of HR changes during episodes of AD.

Spinal cord injury chronically alters cardiac structure and function and is associated with increased odds for cardiovascular disease. Here, we investigate the cardiac consequences of spinal cord injury on the acute-to-chronic continuum, and the contribution of altered bulbospinal sympathetic control to the decline in cardiac function following spinal cord injury. By combining experimental rat models of spinal cord injury with prospective clinical studies, we demonstrate that spinal cord injury causes a rapid and sustained reduction in left ventricular contractile function that precedes structural changes. In rodents, we experimentally demonstrate that this decline in left ventricular contractile function following spinal cord injury is underpinned by interrupted bulbospinal sympathetic control. In humans, we find that activation of the sympathetic circuitry below the level of spinal cord injury causes an immediate increase in systolic function. Our findings highlight the importance for early interventions to mitigate the cardiac functional decline following spinal cord injury.

Background Increasing physical activity (PA) behavior remains a public health priority, and wearable technology is increasingly being used to support behavior change efforts. Using wearables to capture and provide comprehensive, visually persuasive, multidimensional feedback with real-time support may be a promising way of increasing PA in inactive individuals. Objective This study aims to explore whether a 6-week self-monitoring intervention using composite web-based multidimensional PA feedback with real-time daily feedback supports increased PA in adults. Methods A 6-week, mixed methods, 2-armed exploratory randomized controlled trial with 6-week follow-up was used, whereby low to moderately active (PA level [PAL] Results There were no notable differences in any PA outcome immediately after the intervention; however, at 12 weeks, moderate-to-large effects were observed with a mean difference in PAL of 0.09 (95% CI 0.02-0.15; effect size [Hedges g] 0.8), daily moderate-intensity PA of 24 (95% CI 0-45; Hedges g=0.6) minutes, weekly moderate-to-vigorous intensity PA of 195 (95% CI 58-331; Hedges g=0.8) minutes, and steps of 1545 (95% CI 581-2553; Hedges g=0.7). Descriptive analyses suggested that the differences in PA at 12 weeks were more pronounced in women and participants with lower baseline PA levels. Immediately after the intervention, there were favorable differences in autonomous motivation, controlled motivation, perceived competence for PA, and barrier self-efficacy, with the latter sustained at follow-up. Qualitative data implied that the intervention was highly informative for participants and that the real-time feedback element was particularly useful in providing tangible, day-to-day behavioral support. Conclusions Using wearable trackers to capture and present sophisticated multidimensional PA feedback combined with discrete real-time support may be a useful way of facilitating changes in behavior. Further investigation into the ways of optimizing the use of wearables in inactive participants and testing the efficacy of this approach via a robust study design is warranted. Trial Registration ClinicalTrials.gov NCT02432924; https://clinicaltrials.gov/ct2/show/NCT02432924

Cross-sectional construct validation study.To test the construct validity of the Leisure Time Physical Activity Questionnaire for People with Spinal Cord Injury (LTPAQ-SCI) by examining associations between the scale responses and cardiorespiratory fitness (CRF) in a sample of adults living with spinal cord injury (SCI).Three university-based laboratories in Canada.Participants were 39 adults (74% male; M age: 42 ± 11 years) with SCI who completed the LTPAQ-SCI and a graded exercise test to volitional exhaustion using an arm-crank ergometer. One-tailed Pearson's correlation coefficients were computed to examine the association between the LTPAQ-SCI measures of mild-, moderate-, heavy-intensity and total minutes per week of LTPA and CRF (peak volume of oxygen consumption [V̇OMinutes per week of mild-, moderate- and heavy-intensity LTPA and total LTPA were all positively correlated with V̇OPeople with SCI who report higher levels of LTPA on the LTPAQ-SCI also demonstrate greater levels of CRF, with stronger associations between moderate- and heavy-intensity LTPA and CRF than between mild-intensity LTPA and CRF. These results provide further support for the construct validity of the LTPAQ-SCI as a measure of LTPA among people with SCI.

This chapter provides a brief description of the structure and function of the autonomic nervous system (ANS), which is responsible for the involuntary control of visceral organs throughout the human body. The ANS has three main divisions: sympathetic, parasympathetic, and enteric. These continuously monitor and control cardiovascular, bronchopulmonary, sexual, thermoregulatory, lower urinary, and gastrointestinal tract functions. Normally the response of these systems to exercise, environmental challenges, and emotional stress are intricately regulated. ANS dysfunction is commonly prevalent in patients with various neurodegenerative disorders. These can present due to either central or peripheral nervous system aetiologies. In order to determine a correct prognosis for these patients, accurate assessment techniques, described herein, are necessary. The underlying causes of specific autonomic system disorders are also discussed, along with descriptions of various treatment strategies. Medical advances in the field of neurorehabilitation now also provide promising alternative options to address autonomic dysfunctions.

This infographic provides a summary of the use of boosting by athletes with spinal cord injury (SCI); its causes, warning signs and dangers, and the current approach of the International Paralympic Committee (IPC) to testing. Boosting is the intentional induction of autonomic dysreflexia (AD) to enhance performance. AD is a potentially life-threatening condition experienced by many individuals with a SCI, typically at or above the T6 spinal level. It is characterised by a sudden increase in systolic blood pressure (SBP) >20 mm Hg above baseline due to a noxious or non-noxious stimuli below the level of injury, that excites sympathetic preganglionic neurons resulting in vasoconstriction of blood vessels in the lower extremities and trunk.1 Triggers include, but are not limited to, bladder distension, injury or an innocuous stimulus (eg, a tight …

Objectives: To assess; (1) differences in red blood cell distribution width between individuals with chronic (>1 year), motor-complete cervical (n = 21), upper-thoracic (n = 27) and thoracolumbar (n = 15) spinal cord injury and, (2) associations between red blood cell distribution width and cardiorespiratory fitness. Design: Prospective multi-center, cross-sectional study. Methods: Peak oxygen uptake was determined using an upper-body arm-crank exercise test to volitional exhaustion and red blood cell distribution width was measured using an automated hematology system. Results: There were significant (p < 0.009) differences between groups classified by level of injury in absolute and relative peak oxygen uptake, peak power output and red blood cell distribution width. A significant (p < 0.001) large negative association (r = −0.524) was found between relative peak oxygen uptake and red blood cell distribution width. Unbiased recursive partitioning, while revealing study site specific differences in red blood cell distribution width, identified homogenous subgroups based specifically on cardiorespiratory fitness irrespective of additional demographic and injury characteristics. Conclusion: The strong negative association between cardiorespiratory fitness and red blood cell distribution width in individuals with paraplegia parallel those previously observed in non-disabled individuals. Higher red blood cell distribution width values are an independent risk factor for increased cardiovascular mortality, heart failure, and coronary heart disease and may reflect several underlying exacerbated metabolic responses such as oxidative stress and systemic inflammation. These data emphasize the importance of maintaining a high aerobic capacity following spinal cord injury.

Objective: To examine (i) the associations between physical activity dimensions, cardiorespiratory fitness and body composition and, (ii) the associations between physical activity dimensions, cardiorespiratory fitness, body composition and biomarkers of cardiometabolic health in persons with spinal cord injury (SCI). Methods: A cross-sectional prospective cohort study with 7-day follow-up was conducted. Body composition, cardiorespiratory fitness and biomarkers of cardiometabolic health were measured in thirty-three participants with SCI (> 1 year post injury). Physical activity dimensions were objectively assessed over 7-days. Results: Activity energy expenditure (r =.43), physical activity level (r =.39), and moderate-to-vigorous physical activity (MVPA) (r =.48) were significantly (P < 0.001) associated with absolute (L/min) peak oxygen uptake (⩒O 2 peak). ⩒O 2 peak was significantly higher in persons performing ≥150 MVPA minutes/week compared to .30) associations with parameters of metabolic regulation, lipid profiles and inflammatory biomarkers. Relative ⩒O 2 peak (ml/kg/min) was moderately associated with only insulin sensitivity (r = 0.37, P = 0.03). Conclusions: Physical activity dimensions are associated with cardiorespiratory fitness; however, stronger and more consistent associations suggest that poor cardiometabolic health is associated with higher body fat content. Given these findings, the regulation of energy balance should be an important consideration for researchers and clinicians looking to improve cardiometabolic health in persons with SCI.

A narrative review describing various components of sexual dysfunction in men with spinal cord injury (SCI), as well as addressing potential therapeutic approaches.Restoration of sexual function is considered one of the most important health priorities for individuals with SCI. The purpose of this review is to provide information regarding the factors that are less appreciated when considering changes to sexual function in men with SCI. We also propose therapeutic approaches, with a focus on lifestyle modifications, which have been shown to improve sexual function.A literature search was performed and limited evidence for therapeutic approaches in individuals with SCI was supplemented by consistent findings from the able-bodied population.We evaluated the less addressed factors known to contribute to sexual dysfunction in men with SCI, including hormonal influences (i.e., testosterone deficiency, thyroid hormone, and cortisol), psychological factors (i.e., pain, fatigue, depression, and body image), and secondary SCI complications (i.e., urinary tract infection, pressure sores, and autonomic dysreflexia). To address these factors beyond standard medical treatments for sexual dysfunction, options include physical activity/exercise, diet, and specific medications for symptom relief (i.e., testosterone replacement therapy and selective serotonin reuptake inhibitors for depression).Physical activity's potential application, efficacy across multiple aspects of sexuality, and the lack of side effects, suggests that long-term exercise is a viable solution to directly or indirectly improve sexual function in males with SCI. Diet and supplemental medications may further promote body composition changes, which more broadly affect sexuality.

This study: 1) compared cognitive functioning between individuals with chronic (>1 year) spinal cord injury (SCI) and non-injured controls and, 2) assessed associations between symptoms of autonomic dysreflexia and orthostatic hypotension with cognitive functioning in SCI participants with a history of unstable blood pressure (BP). Thirty-two individuals with SCI (C4-L2, American Spinal Injury Association Impairment Scale A-D) and thirty age, sex-matched non-injured controls participated in this study. Participants completed a motor-free neuropsychological test battery assessing 1) memory, 2) attention/concentration/psychomotor speed and, 3) executive function. Nineteen participants with SCI who had injuries ≥T6 and a history of unstable BP also completed the Autonomic Dysfunction Following Spinal Cord Injury (ADFSCI) questionnaire. Cognitive function was significantly lower in people with SCI across measures of memory and executive function compared to non-injured controls. Significant, moderate-to-large associations were observed between cumulative (frequency x severity) orthostatic hypotension and total BP instability symptoms scores, with measures of attention/concentration/psychomotor speed and executive function. These data demonstrate a 10 - 65% reduced performance across specific realms of cognitive functioning in individuals with SCI relative to non-injured controls. Furthermore, cumulative subjective scores for symptoms of unstable BP were associated with diverse cognitive deficits. These findings, in individuals without co-occurring traumatic brain injury, imply cardiovascular dysregulation plays a role in cognitive deficits observed in this population.

INTRODUCTION AND OBJECTIVES:Neurogenic detrusor overactivity (NDO) is a leading trigger of autonomic dysreflexia (AD) in patients with spinal cord injury (SCI). Antimuscarinics, such as fesoterodin...

Individuals with a spinal cord injury (SCI) ≥T6 level exhibit impaired cardiovascular responses to exercise that can limit exercise capacity.1 The burgeoning field of neuromodulation has recently demonstrated that epidural spinal cord stimulation (ESCS), configured to facilitate motor function in humans with SCI, can also modulate cardiovascular function (i.e., increasing or maintaining arterial blood pressure at rest or in response to an orthostatic challenge, respectively).2–4 Here we present a unique application of ESCS to improve upper body exercise capacity in an individual with SCI, via the modulation of cardiovascular and respiratory function.

PURPOSE To assess the validity of a derived algorithm, combining tri-axial accelerometry and heart rate (HR) data, compared to a research-grade multi-sensor physical activity device, for the estimation of ambulatory physical activity energy expenditure (PAEE) in individuals with traumatic lower-limb amputation. METHODS Twenty-eight participants [unilateral (n = 9), bilateral (n = 10) with lower-limb amputations, and non-injured controls (n = 9)] completed eight activities; rest, ambulating at 5 progressive treadmill velocities (0.48, 0.67, 0.89, 1.12, 1.34m.s-1) and 2 gradients (3 and 5%) at 0.89m.s-1. During each task, expired gases were collected for the determination of [Formula: see text] and subsequent calculation of PAEE. An Actigraph GT3X+ accelerometer was worn on the hip of the shortest residual limb and, a HR monitor and an Actiheart (AHR) device were worn on the chest. Multiple linear regressions were employed to derive population-specific PAEE estimated algorithms using Actigraph GT3X+ outputs and HR signals (GT3X+HR). Mean bias±95% Limits of Agreement (LoA) and error statistics were calculated between criterion PAEE (indirect calorimetry) and PAEE predicted using GT3X+HR and AHR. RESULTS Both measurement approaches used to predict PAEE were significantly related (P

This study aimed to assess the accuracy of existing basal metabolic rate (BMR) prediction equations in men with chronic (1 yr) spinal cord injury (SCI). The primary aim is to develop new SCI population-specific BMR prediction models, based on anthropometric, body composition, and/or demographic variables that are strongly associated with BMR.Thirty men with chronic SCI (paraplegic, n = 21, tetraplegic, n = 9) 35 ± 11 yr old (mean ± SD) participated in this cross-sectional study. Criterion BMR values were measured by indirect calorimetry. Body composition (dual-energy x-ray absorptiometry) and anthropometric measurements (circumferences and diameters) were also taken. Multiple linear regression analysis was performed to develop new SCI-specific BMR prediction models. Criterion BMR values were compared with values estimated from six existing and four developed prediction equations.Existing equations that use information on stature, weight, and/or age significantly (P0.001) overpredicted measured BMR by a mean of 14%-17% (187-234 kcal·d). Equations that used fat-free mass (FFM) accurately predicted BMR. The development of new SCI-specific prediction models demonstrated that the addition of anthropometric variables (weight, height, and calf circumference) to FFM (model 3; r = 0.77), explained 8% more of the variance in BMR than FFM alone (model 1; r = 0.69). Using anthropometric variables, without FFM, explained less of the variance in BMR (model 4; r = 0.57). However, all the developed prediction models demonstrated acceptable mean absolute error ≤6%.BMR can be more accurately estimated when dual-energy x-ray absorptiometry-derived FFM is incorporated into prediction equations. Using anthropometric measurements provides a promising alternative to improve the prediction of BMR, beyond that achieved by existing equations in persons with SCI.

Background/Objectives To examine associations of different anthropometric measurements of central adiposity to visceral adipose tissue (measured via multi-axial magnetic resonance imaging; MRI) and cardiometabolic disease risk factors in men with spinal cord injury (SCI). Additionally, to determine population-specific seated/supine waist and abdominal circumference cutoffs, which may identify men at increased risk of cardiometabolic disease. Participants/Methods Twenty-two men with chronic SCI underwent MRI scans, anthropometric measurements along with assessments of various cardiometabolic risk biomarkers. Pearson/part (accounting for age as a covariate) correlation coefficients were calculated to determine the associations between study variables. Abdominal and waist circumference cutoffs were extrapolated using the slope of linear regression equations. Results Seated/supine abdominal and waist circumferences were (P < 0.01) associated with MRI visceral fat cross-sectional area (VATCSA), VAT volume and CSA:TotalCSA. Low density lipoprotein, non-high-density lipoprotein and total cholesterol were positively associated with seated/supine abdominal and waist circumferences after controlling for age; r = 0.50–0.61, r = 0.46–0.58, r = 0.52–0.58, P < 0.05, respectively. Tumor necrosis factor alpha was associated with seated/supine abdominal and waist circumferences after accounting for age; r = 0.49–0.51 and r = 0.48–0.56, P < 0.05 respectively. The population-specific cutoffs were 86.5cm and 88.3cm for supine waist and abdominal circumferences, respectively, as well as 89cm and 101cm for seated waist and abdominal circumferences, respectively. After dichotomizing VATCSA (< or ≥ 100cm2), peak oxygen uptake, triglycerides, insulin sensitivity and glycated hemoglobin were different (P < 0.05) between groups. After dichotomizing (< or ≥ 86.5cm) supine waist circumference, VATCSA, triglycerides and insulin sensitivity were different (P < 0.05) between groups. Conclusions Seated/supine circumferences are associated with both central adiposity and biomarkers of cardiometabolic disease risk in persons with SCI. Population-specific cutoffs are proposed herein to identify central adiposity and potential cardiometabolic disease risk after SCI.

CONTEXT: Hypogonadism is a male clinical condition in which the body does not produce enough testosterone. Testosterone plays a key role in maintaining body composition, bone mineral density, sexual function, mood, erythropoiesis, cognition and quality of life. Hypogonadism can occur due to several underlying pathologies during aging and in men with physical disabilities, such as spinal cord injury (SCI). This condition is often under diagnosed and as a result, symptoms undertreated. METHODS: In this mini-review, we propose that testosterone replacement therapy (TRT) might be a viable strategy to improve lean body mass (LBM) and fat mass (FM) in men with SCI. EVIDENCE SYNTHESIS: Supplementing the limited data from SCI cohorts with consistent findings from studies in non-disabled aging men, we present evidence that, relative to placebo, transdermal TRT can increase LBM and reduce FM over 3 – 36 months. The impact of TRT on bone mineral density and metabolism is also discussed, with particular relevance for persons with SCI. Moreover, the risks of TRT remain controversial and pertinent safety considerations related to transdermal administration are outlined. CONCLUSION: Further research is necessary to help develop clinical guidelines for the specific dose and duration of TRT in persons with SCI. Therefore, we call for more high-quality randomized controlled trials to examine the efficacy and safety of TRT in this population, who experience an increased risk of cardiometabolic diseases as a result of deleterious body composition changes after injury.

Background Despite obesity being highly prevalent in persons with spinal cord injury (SCI), our current understanding of the interactions between energy balance components, which may contribute to this, is limited. The primary aim of this study is to identify the intra-individual variability of physical activity dimensions across days and suggest an appropriate monitoring time frame for these constructs in adults with SCI. The secondary aim is to examine these parameters with regard to energy intake and dietary macronutrient composition. Methods Participants [33 men and women with chronic (> 1 year post injury) paraplegia; age = 44 ± 9 years (mean ± S.D.] wore an Actiheart™ PA monitor and completed a weighed food diary for 7 consecutive days. Spearman-Brown Prophecy Formulae, based on Intraclass Correlations of .80 (acceptable reliability), were used to predict the number of days required to measure energy balance components. Linear mixed-effects analyses and magnitude-based inferences were performed for all energy intake, expenditure and physical activity dimensions. Adjustments were made for age, injury level, wear time, sex, day of the week and measurement order as fixed effects. Results To reliably measure energy expenditure components; 1 day [total energy expenditure (TEE)], 2 days [physical activity energy expenditure (PAEE), light-intensity activity, moderate-to-vigorous PA (MVPA)], 3 days [physical activity level (PAL)] and 4 days (sedentary behaviour) are necessary. Device wear time (P 1 year) paraplegia and propose suitable measurement durations to achieve acceptable reliability in outcome measures. Device wear time and measurement order play a role in the quality of energy expenditure and intake data, respectively, and should be considered when designing and analysing studies of energy balance components in persons with SCI. Trial registration N/A

Purpose Spinal cord injury (SCI) creates a complex pathology, characterized by low levels of habitual physical activity and an increased risk of cardiometabolic disease. This study aimed to assess the effect of a moderate-intensity upper-body exercise training intervention on biomarkers of cardiometabolic component risks, adipose tissue metabolism, and cardiorespiratory fitness in persons with SCI. Methods Twenty-one inactive men and women with chronic (>1 yr) SCI (all paraplegic injuries) 47 ± 8 yr of age (mean ± SD) were randomly allocated to either a 6-wk prescribed home-based exercise intervention (INT; n = 13) or control group (CON; n = 8). Participants assigned to the exercise group completed 4 × 45-min moderate-intensity (60%–65% peak oxygen uptake (V˙O2peak)) arm-crank exercise sessions per week. At baseline and follow-up, fasted and postload blood samples (collected during oral glucose tolerance tests) were obtained to measure metabolic regulation and biomarkers of cardiovascular disease. Abdominal subcutaneous adipose tissue biopsies were also obtained, and cardiorespiratory fitness was assessed. Results Compared with CON, INT significantly decreased (P = 0.04) serum fasting insulin (Δ, 3.1 ± 10.7 pmol·L−1 for CON and −12.7 ± 18.7 pmol·L−1 for INT) and homeostasis model assessment of insulin resistance (HOMA2-IR; Δ, 0.06 ± 0.20 for CON and −0.23 ± 0.36 for INT). The exercise group also increased V˙O2peak (Δ, 3.4 mL·kg−1·min−1; P ≤ 0.001). Adipose tissue metabolism, composite insulin sensitivity index (C-ISIMatsuda), and other cardiovascular disease risk biomarkers were not different between groups. Conclusions Moderate-intensity upper-body exercise improved aspects of metabolic regulation and cardiorespiratory fitness. Changes in fasting insulin and HOMA2-IR, but not C-ISIMatsuda, suggest improved hepatic but not peripheral insulin sensitivity after 6 wk of exercise training in persons with chronic paraplegia.

Wearable physical activity monitors are growing in popularity and provide the opportunity for large numbers of the public to self-monitor physical activity behaviours. The latest generation of these devices feature multiple sensors, ostensibly similar or even superior to advanced research instruments. However, little is known about the accuracy of their energy expenditure estimates. Here, we assessed their performance against criterion measurements in both controlled laboratory conditions (simulated activities of daily living and structured exercise) and over a 24 hour period in free-living conditions. Thirty men (n = 15) and women (n = 15) wore three multi-sensor consumer monitors (Microsoft Band, Apple Watch and Fitbit Charge HR), an accelerometry-only device as a comparison (Jawbone UP24) and validated research-grade multi-sensor devices (BodyMedia Core and individually calibrated Actiheart™). During discrete laboratory activities when compared against indirect calorimetry, the Apple Watch performed similarly to criterion measures. The Fitbit Charge HR was less consistent at measurement of discrete activities, but produced similar free-living estimates to the Apple Watch. Both these devices underestimated free-living energy expenditure (-394 kcal/d and -405 kcal/d, respectively; P