Louis De Beaumont

Post-concussion symptoms (PCS) affect a minority of individuals after mild traumatic brain injury (mTBI) or sport-related concussion (SRC), yet they impose a disproportionate burden (Hiploylee et a...

Background: Spinal cord injury (SCI) disrupts neuronal pathways, alters spinal reflexes, and often leads to spasticity—a condition of increased muscle tone and involuntary contractions that interfere with daily function. Spasticity typically emerges progressively after injury; however, its mechanisms remain poorly understood, particularly regarding why it develops in some individuals but not in others. Increased spinal excitability has been implicated, but prospective evidence remains scarce. Objective: This pilot, proof-of-concept study explored whether early electrophysiological markers of spinal excitability, specifically the soleus H-reflex and post-activation depression (PAD), could be linked to the subsequent development of spasticity during intensive functional rehabilitation (IFR). Methods: Seventeen individuals with traumatic SCI were assessed. The Hmax/Mmax ratio and PAD were measured prior to or shortly after IFR admission. At IFR admission and discharge, spasticity (Modified Ashworth Scale and clonus) and motor function (Lower Extremity Motor Score, LEMS) were evaluated. Each lower limb was analyzed separately to account for asymmetry. Correlations between early electrophysiological measures and clinical outcomes were examined. Results: Spasticity measures tended to increase from IFR admission to discharge, but only LEMS improved significantly, reflecting motor recovery. Several participants did not present spasticity at admission or discharge. A higher Hmax/Mmax ratio and reduced PAD at early IFR were associated with greater clonus at both admission and discharge, whereas no significant associations were found with Ashworth scores. Across injury levels and AIS grades, AIS A participants displayed the lowest Hmax/Mmax ratios and minimal spasticity, while AIS B or D participants with H/M ratios exceeding 0.2 in early IFR developed clonus. Conclusion: These exploratory findings suggest that early signs of spinal hyperexcitability reflect spasticity development, but it does not show that they precedes spasticity development, which would be required to support its prognostic value. Assessment at earlier timepoints, such as in acute care, would be necessary to validate both the Hmax/Mmax ratio and the PAD as predictive measures of spasticity in SCI. While not clinically generalizable due to the small and heterogeneous sample, this proof-of-concept study highlights the feasibility and potential value of H-reflex as early markers of spasticity. Larger, adequately powered studies stratified by injury level and severity are needed to confirm utility and clinical applicability.

Purpose: Predicting in-game heart rate (HR) in dynamic team sports remains challenging due to limitations of models developed under controlled, laboratory-based conditions. We address this by developing a context-aware framework that forecasts HR dynamics using linear time-invariant (LTI) models, and examine whether these context-sensitive parameters serve as interpretable markers of athlete-or game-level stressors. Methods: We used HR data from 72 university football players over two seasons. First-order LTI systems, with steady-state gain (SSG) and time constant (τ), modeled this data. A gradient boosting regressor predicted SSG and τ for upcoming quarters, using workload, head impact, and BMI as inputs. Model performance was assessed via R2, RMSE, and MAE, compared to population average LTI models. Associations of SSG and τ parameters with athlete- or game-level stressors were also analyzed. Results: The dynamically tuned LTI model significantly outperformed the fixed-parameter baseline in HR prediction accuracy. Furthermore, predicted LTI parameters demonstrated meaningful associations with exertion levels, head impact exposure, and athlete BMI. Conclusion: Context-aware LTI modeling offers both accurate HR forecasting and interpretable physiological insights during competition. This approach lays the groundwork for real-time athlete monitoring and autonomous decision- support systems in high-performance sports environments.

Background/Objectives: The insula is a deep, functionally heterogeneous region involved in various pathological conditions. Repetitive transcranial magnetic stimulation (rTMS) has emerged as a promising therapeutic avenue for neuromodulation, yet very few studies have directly investigated its effects on insular activity. Moreover, empirical evidence of target engagement of this region remains scarce. This study aimed to stimulate the insula with rTMS and assess blood oxygen level-dependent (BOLD) signal modulation using concurrent functional magnetic resonance imaging (fMRI). Methods: Ten participants were recruited, six of whom underwent a single session of 5 Hz high-frequency rTMS over the right insular cortex inside the MRI scanner. Stimulation was delivered using a compatible MRI-B91 TMS coil. Stimulation consisted of 10 trains of 10 s each, with a 50 s interval between trains. Frameless stereotactic neuronavigation ensured precise targeting. Paired t-tests were used to compare the mean BOLD signal obtained between stimulation trains with resting-state fMRI acquired before the rTMS stimulation session. A significant cluster threshold of q < 0.01 (False Discovery Rate; FDR) with a minimum cluster size of 10 voxels was applied. Results: Concurrent rTMS-fMRI revealed the significant modulation of BOLD activity within insular subregions. Increased activity was observed in the anterior, middle, and middle-inferior insula, while decreased activity was identified in the ventral anterior and posterior insula. Additionally, two participants reported transient dysgeusia following stimulation, which provides further evidence of insular modulation. Conclusions: These findings provide preliminary evidence that rTMS can modulate distinct subregions of the insular cortex. The combination of region-specific BOLD responses and stimulation-induced dysgeusia supports the feasibility of using rTMS to modulate insular activity.

Background/Objectives: The insula plays a role in various medical conditions, including eating disorders, addiction, and chronic pain. Repetitive transcranial magnetic stimulation (rTMS) has emerged as a promising therapeutic avenue, yet few studies have investigated its modulation effects on the insula. Moreover, direct evidence of target engagement remains scarce. This study aimed to stimulate the insula with rTMS and assess BOLD signal modulation through concurrent functional magnetic resonance imaging (fMRI). Methods: Ten participants were recruited and six underwent a single session of 5 Hz high-frequency rTMS over the right insular cortex inside the MRI scanner, using a compatible MRI-B91 TMS coil. Stimulation consisted of 10 trains of 10 seconds, with 50-second interval between trains. Frameless stereotactic neuronavigation ensured precise targeting. Paired t-tests were used to compare the mean BOLD signal obtained between stimulation trains with resting-state fMRI acquired before the rTMS stimulation session (significant cluster threshold of 10 voxels; False Discovery Rate at q < 0.01). Results: Increased activity was observed in the anterior, middle, and middle-inferior insula, while deactivations occurred in the ventral anterior and posterior insula. Two participants reported dysgeusia, providing further evidence of insular modulation. Conclusions: This study provides neuroimaging evidence for rTMS-induced insular modulation. Our results are highly relevant for future clinical applications, with potential therapeutic avenues in individuals with conditions where insular dysfunction plays a key role.

Head finite element models (hFEMs) are valuable in understanding injury mechanisms in head impacts. Personalizing hFEMs is important for capturing individualized brain responses, with brain volume scaling proving effective. However, the role of refined white matter (WM) parcellation in hFEMs for evaluating brain strain responses, particularly important in the context of subconcussive head impacts (SHIs) often assessed through changes in WM integrity, remains relatively underexplored. This study evaluated the effect of refined subject-specific WM parcellation in 34 WM segments on responses variability due to brain volume variations, using peak maximum principal strain (95MPS) and strain rate (95MPSr) as injury predictive metrics. Data from diffusion-weighted imaging of 21 Canadian varsity football players were utilized to personalize 21 hFEMs. Simulating four different head impacts, representing 50th and 99th percentile resultant accelerations in frontal and angled-top-right directions, refined player-specific WM parcellation better captured variability of strain responses compared to baseline parcellation. Up to 75.71% of 95MPS and 77.14% of 95MPSr responses were deemed different across refined WM segments for players, compared to a maximum of 16.19% of responses with baseline parcellation. These results suggest that player-specific refined WM parcellation improves the ability to capture player-specific responses. Both impact direction and intensity influenced variations in strain response, with angled-top head impacts combined with high intensity showing greater player-specificity compared to lower intensity and frontal head impacts. These findings highlight the potential benefit of model scaling along with player-specific refined WM parcellation in hFEMs for comprehensively evaluating strain responses. Detailed WM parcellation in hFEMs is important for comprehensive injury assessment, enhancing the alignment of hFEMs with imaging studies evaluating changes in WM integrity across segments. The simple and straightforward method presented herein to achieve player-specific strain response is promising for future SHI studies.

Introduction Acute pain levels following orthopaedic injury (eg, fracture) are a predictor of the onset of chronic pain, which affects nearly 50% of fracture patients and impairs functional recovery. Among current pharmacological treatments for acute pain, non-steroidal anti-inflammatory drugs have been associated with delayed bone healing, while opioids inhibit effective bone remodelling, increase the risk of pseudarthrosis and carry a high risk of addiction. In light of this, the development of new pain treatments is essential. Cannabidiol (CBD), a non-addictive and non-psychotropic cannabis component stands out as a potential therapeutic agent, given its analgesic and anti-inflammatory properties as well as its potential benefits for bone healing. This randomised controlled trial aims to investigate the effect of acute CBD treatment, compared with placebo, on patients’ self-reported pain, inflammation and well-being following a fracture injury. Methods and analysis This is a triple-blind, randomised, placebo-controlled clinical trial. A total of 225 adults aged 18–70 years, who have suffered a long bone fracture and were treated at the Hôpital du Sacré-Coeur de Montréal, will be randomly assigned within 1 week to one of three treatment arms (25 mg or 50 mg of CBD or placebo) for 1 month. The primary outcome will be the difference in the pain score between groups at 1-month follow-up. Secondary outcomes will include measures of persistent pain, inflammation, opioid usage, quality of life, sleep quality, depression, anxiety, cognition and orthopaedic function. Data will be collected at baseline, 1-month and 3-month follow-ups. Ethics and dissemination This study obtained a Health Canada licence for use of cannabis products. It has also been approved by Health Canada and the Research Ethics Board of the CIUSSS du Nord-de-l’Île-de-Montréal (Project ID 2025-2105). The findings will be published in a peer-reviewed journal and presented at local, national and international conferences. The trial’s results will be made publicly available on the ClinicalTrials.gov database. Trial registration number NCT06448923.