TractLearn: A geodesic learning framework for quantitative analysis of brain bundles.

Deep learning-based convolutional neural networks have recently proved their efficiency in providing fast segmentation of major brain fascicles structures, based on diffusion-weighted imaging. The quantitative analysis of brain fascicles then relies on metrics either coming from the tractography process itself or from each voxel along the bundle. Statistical detection of abnormal voxels in the context of disease usually relies on univariate and multivariate statistics models, such as the General Linear Model (GLM). Yet in the case of high-dimensional low sample size data, the GLM often implies high standard deviation range in controls due to anatomical variability, despite the commonly used smoothing process. This can lead to difficulties to detect subtle quantitative alterations from a brain bundle at the voxel scale. Here we introduce TractLearn, a unified framework for brain fascicles quantitative analyses by using geodesic learning as a data-driven learning task. TractLearn allows a mapping between the image high-dimensional domain and the reduced latent space of brain fascicles using a Riemannian approach. We illustrate the robustness of this method on a healthy population with test-retest acquisition of multi-shell diffusion MRI data, demonstrating that it is possible to separately study the global effect due to different MRI sessions from the effect of local bundle alterations. We have then tested the efficiency of our algorithm on a sample of 5 age-matched subjects referred with mild traumatic brain injury. Our contributions are to propose: 1/ A manifold approach to capture controls variability as standard reference instead of an atlas approach based on a Euclidean mean. 2/ A tool to detect global variation of voxels' quantitative values, which accounts for voxels' interactions in a structure rather than analyzing voxels independently. 3/ A ready-to-plug algorithm to highlight nonlinear variation of diffusion MRI metrics. With this regard, TractLearn is a ready-to-use algorithm for precision medicine.

Changes in resting-state functional brain connectivity associated with head impacts over one men's semi-professional soccer season.

Soccer, as a contact sport, exposes players to repetitive head impacts, especially through heading the ball. The question of a long-term brain cumulative effect remains. Our objective was to determine whether exposure to head impacts over one soccer season was associated with changes in functional brain connectivity at rest, using magnetic resonance imaging (MRI). In this prospective cohort study, 10 semi-professional men soccer players, aged 18-25 years, and 20 age-matched men athletes without a concussion history and who do not practice any contact sport were recruited in Bordeaux (France). Exposure to head impacts per soccer player during competitive games over one season was measured using video analysis. Resting-state functional magnetic resonance imaging data were acquired for both groups at two times, before and after the season. With a seed-based analysis, resting-state networks that have been intimately associated with aspects of cognitive functioning were investigated. The results showed a mean head impacts of 42 (±33) per soccer player over the season, mainly intentional head-to-ball impacts and no concussion. No head impact was found among the other athletes. The number of head impacts between the two MRI acquisitions before and after the season was associated with increased connectivity within the default mode network and the cortico-cerebellar network. In conclusion, our findings suggest that the brain functioning changes over one soccer season in association with exposure to repetitive head impacts.

Video analysis of concussion mechanisms and immediate management in French men's professional football (soccer) from 2015 to 2019.

In this study, the concussion mechanisms were analyzed in male professional competition football, with the main objective to specify the frequency of head-to-head impact, and immediate management of the concussed players was described in order to check its compliance with the recommendations of football's governing bodies. Based on continuously recorded data from the French Football Federation (FFF), a retrospective database of all reported concussions during matches in the 1st and 2nd French Male leagues was generated comprising seasons 2015/16-2018/19. Injury mechanisms, playing action, immediate medical assessment and management of concussed players, and foul play-referee's decision, were analyzed from video recordings. In total, 41 concussions were reported (incidence rate of 0.44/1000 hours of match exposure [95% CI: 0.40 to 0.49]) of which 36 were identified and analyzed on video sequences. The commonest playing action leading to concussion was aerial challenge (61%), and the main mechanism was head-to-head impact (47%). Following the head impact, 28% of concussed players were not medically assessed on pitch and 53% returned to play the same match. Head-to-head impact was not associated with systematic medical assessment, nor with foul play. In conclusion, the main cause of concussions involved head-to-head impact occurring when two players challenge for heading the ball in the air. The detection of potential concussive head impacts and the immediate management of players possibly concussed during matches remain insufficient according to the international recommendations. Some rules changes, with particular vigilance in case of head-to-head impact, should be discussed.

Head impacts in semiprofessional male Soccer players: a prospective video analysis over one season of competitive games.

Soccer exposes players to head injuries and involves repeated intentional head impacts through heading the ball. Our objective was to investigate the rate of both intentional headers and involuntary head impacts in semiprofessional male soccer players during one season. In this prospective cohort study, we followed 54 men (16-35 years) playing in two soccer clubs participating in the same regional French championship throughout the 2017-2018 season. All head impacts that occurred in competitive games were analyzed using video recordings. Player position, game exposure, referee's decision were also reported. Head impact incidence rate (IR) per 1000 player-hours, with the 95% confidence intervals (CIs) were calculated. Results: Headers IR was 3584.7 per 1000 player-hours (95% CI = 3431.9, 3737.5). Forwards and center-backs performed a higher number of headers. Involuntary head impacts IR was 44.1/1000 player-hours (95% CI = 27.1, 60.9). Just under half led the referee to stop playing time for a caregiver examination. Three concussions with a loss of consciousness after a head-to-head impact in a heading duel were recorded. Conclusions: Intentional headers were relatively common, contrary to involuntary head impacts that were however mainly due to heading duels. Head-to-head impact should lead to a systematic exit from the game for suspicion of concussion.

Could trochanteric pelvic stabilization be removed from the adolescent idiopathic scoliosis brace? A prospective pilot study.

BACKGROUND: Idiopathic scoliosis is the most common musculoskeletal deformity in children. There is a dose-response relationship between compliance and improvement in scoliosis. The literature revealed that esthetic considerations have negative consequences on the quality of life (QOL) of patients and consequently on wearing time of the brace. To minimize esthetic problems and then increase QOL and wearing time, we proposed a new relay brace named "corset Collerette" without a pelvic-trochanteric base. METHODS: A prospective cohort study was conducted in the rehabilitation department of Bordeaux University Hospital. Patients consulting for adolescent idiopathic scoliosis were registered in a prospective hospital database. The patients expressing unwillingness to wear the usual brace or who had decreased compliance were offered the corset Collerette and were included in a 3-month follow-up. Outcome measures assessed at baseline and at 3 months were Scoliosis Research Society Outcomes Questionnaire (SRS-22) and Brace Questionnaire scales and wearing time. Cobb's angle evolution since the start of bracing was also collected. The primary end point was the QOL assed by the SRS-22 scale at 3 months of follow-up. RESULTS: The first 38 patients agreeing to wear the corset Collerette were included in the study. The QOL assessed by the SRS-22 was significantly improved with the corset Collerette ( p < 0.05). There was no significant increase in wearing time and thoracic Cobb's angles between baseline and follow-up ( p > 0.05). CONCLUSION: The switch to the corset Collerette allowed an improvement in the QOL of the patients and avoid a decrease in compliance with wearing the brace and maintain the same in-brace Cobb's angles.

A systematic review of repetitive transcranial magnetic stimulation in aphasia rehabilitation: Leads for future studies.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive tool that induces neuromodulation in the brain. Several studies have shown that rTMS improves language recovery in patients with post-stroke aphasia. OBJECTIVE: This systematic review summarizes the role of rTMS in aphasia rehabilitation. METHODS: We searched MEDLINE via PubMed and Scopus on 30October, 2020, for English articles (1996-2020). Eligible studies involved post-stroke aphasia rehabilitation with rTMS. In some of these studies, rTMS was also combined with speech therapy. RESULTS: In total, seven meta-analyses and 59studies (23randomized clinical trials) were included in this systematic review. The methods used in these studies were heterogeneous. Only six studies did not find that rTMS had a significant effect on language performance. CONCLUSIONS: The evidence from the peer-reviewed literature suggests that rTMS is an effective tool in post-stroke aphasia rehabilitation. However, the precise mechanisms that underlie the effects of rTMS and the reorganization of language networks in patients who have had a stroke remain unclear. We discuss these crucial challenges in the context of future studies.

Effects of robotic gait training after stroke: A meta-analysis.

BACKGROUND: Robotic devices are often used in rehabilitation and might be efficient to improve walking capacity after stroke. OBJECTIVE: First to investigate the effects of robot-assisted gait training after stroke and second to explain the observed heterogeneity of results in previous meta-analyses. METHODS: All randomized controlled trials investigating exoskeletons or end-effector devices in adult patients with stroke were searched in databases (MEDLINE, EMBASE, CENTRAL, CINAHL, OPENGREY, OPENSIGLE, PEDRO, WEB OF SCIENCE, CLINICAL TRIALS, conference proceedings) from inception to November 2019, as were bibliographies of previous meta-analyses, independently by 2 reviewers. The following variables collected before and after the rehabilitation program were gait speed, gait endurance, Berg Balance Scale (BBS), Functional Ambulation Classification (FAC) and Timed Up and Go scores. We also extracted data on randomization method, blinding of outcome assessors, drop-outs, intention (or not) to treat, country, number of participants, disease duration, mean age, features of interventions, and date of outcomes assessment. RESULTS: We included 33 studies involving 1466 participants. On analysis by subgroups of intervention, as compared with physiotherapy alone, physiotherapy combined with body-weight support training and robot-assisted gait training conferred greater improvement in gait speed (+0.09m/s, 95% confidence interval [CI] 0.03 to 0.15; p=0.002), FAC scores (+0.51, 95% CI 0.07 to 0.95; p=0.022) and BBS scores (+4.16, 95% CI 2.60 to 5.71; p=0.000). A meta-regression analysis suggested that these results were underestimated by the attrition bias of studies. CONCLUSIONS: Robot-assisted gait training combined with physiotherapy and body-weight support training seems an efficient intervention for gait recovery after stroke.

Evaluation of a virtual agent to train medical students conducting psychiatric interviews for diagnosing major depressive disorders.

BACKGROUND: A psychiatric diagnosis involves the physician's ability to create an empathic interaction with the patient in order to accurately extract semiology (i.e., clinical manifestations). Virtual patients (VPs) can be used to train these skills but need to be evaluated in terms of accuracy, and to be perceived positively by users. METHODS: We recruited 35 medical students who interacted in a 35-min psychiatric interview with a VP simulating major depressive disorders. Semiology extraction, verbal and non-verbal empathy were measured objectively during the interaction. The students were then debriefed to collect their experience with the VP. RESULTS: The VP was able to simulate the conduction of a psychiatric interview realistically, and was effective to discriminate students depending on their psychiatric knowledge. Results suggest that students managed to keep an emotional distance during the interview and show the added value of emotion recognition software to measure empathy in psychiatry training. Students provided positive feedback regarding pedagogic usefulness, realism and enjoyment in the interaction. LIMITATIONS: Our sample was relatively small. As a first prototype, the measures taken by the VP would need improvement (subtler empathic questions, levels of difficulty). The face-tracking technique might induce errors in detecting non-verbal empathy. CONCLUSION: This study is the first to simulate a realistic psychiatric interview and to measure both skills needed by future psychiatrists: semiology extraction and empathic communication. Results provide evidence that VPs are acceptable by medical students, and highlight their relevance to complement existing training and evaluation tools in the field of affective disorders.

New factors that affect quality of life in patients with aphasia.

BACKGROUND: Aphasia severity is known to affect quality of life (QoL) in stroke patients, as is mood disorders, functional limitations, limitations on activities of daily life, economic status and level of education. However, communication limitation or fatigue has not been explored in this specific population. OBJECTIVE: We aimed to investigate whether these factors were associated with QoL in patients with aphasia after stroke. METHODS: Patients with aphasia were included from April 2014 to November 2017 after a first stroke and were followed for 2 years post-stroke. QoL was assessed at follow-up by the French Sickness Impact Profile 65 (SIP-65). We explored predictors such as mood disorders, communication impairment, fatigue, limitations on activities of daily life, and aphasia severity in addition to socio-demographic factors. RESULTS: We included 32 individuals (22 men; mean age 60.7 [SD 16.6] years) with aphasia after a first stroke. Poor QoL as assessed by the SIP-65 was significantly associated (Pearson correlations) with increased severity of aphasia initially (P=0.008) and at follow-up (P=0.01); increased communication activity limitations at follow-up (P<0.001); increased limitations on activities of daily life at baseline (P=0.008) and follow-up (P<0.001); increased fatigue at follow-up (P=0.001); and increased depression symptoms at follow-up (P=0.001). On multivariable analysis, QoL was associated with communication activity limitations, limitations on activities of daily life, fatigue and depression, explaining more than 75% of the variance (linear regression R2=0.756, P<0.001). The relative importance in predicting the variance was 32% for limitations on activities of daily life, 21% fatigue, 23% depression and 24% communication activity limitations. CONCLUSION: Aphasia severity, mood disorders and functional limitations may have a negative effect on QoL in patients with aphasia. Also, for the first time, we show that fatigue has an important impact on QoL in this population. Specific management of this symptom might be beneficial and should be explored in future studies.

Transcranial direct current stimulation in post-stroke aphasia rehabilitation: A systematic review.

BACKGROUND: Transcranial direct current stimulation (tDCS) is a non-invasive tool that induces neuromodulation in the brain. Several studies have shown the effectiveness of tDCS in improving language recovery in post-stroke aphasia. However, this innovative technique is not currently used in routine speech and language therapy (SLT) practice. OBJECTIVE: This systematic review aimed to summarise the role of tDCS in aphasia rehabilitation. METHODS: We searched MEDLINE via PubMed and Scopus on October 5, 2018 for English articles published from 1996 to 2018. Eligible studies involved post-stroke aphasia rehabilitation with tDCS combined or not with SLT. RESULTS: We retained 5 meta-analyses and 48 studies. Among the 48 studies, 39 were randomised controlled trials (558 patients), 2 prospective studies (56 patients), and 5 case studies (5 patients). Two articles were sub-analyses of a randomised clinical trial. Methods used in these studies were heterogeneous. Only 6 studies did not find a significant effect of tDCS on language performance. As compared with earlier meta-analyses, the 2 latest found significant effects. CONCLUSION: Evidence from published peer reviewed literature is effective for post-stroke aphasia rehabilitation at the chronic stages. tDCS devices are easy to use, safe and inexpensive. They can be used in routine clinical practice by speech therapists for aphasia rehabilitation. However, further studies should investigate the effectiveness in the subacute post-stroke phase and determine the effect of the lesion for precisely identifying the targeted brain areas. We discuss crucial challenges for future studies.