Coherent, time-shifted patterns of microstructural plasticity during motor-skill learning.

Motor skill learning relies on neural plasticity in the motor and limbic systems. However, the spatial and temporal characteristics of these changes-and their microstructural underpinnings-remain unclear. Eighteen healthy males received 1 h of training in a computer-based motion game, 4 times a week, for 4 consecutive weeks, while 14 untrained participants underwent scanning only. Performance improvements were observed in all trained participants. Serial myelin- and iron-sensitive multiparametric mapping at 3T during this period of intensive motor skill acquisition revealed temporally and spatially distributed, performance-related microstructural changes in the grey and white matter across a corticospinal-cerebellar-hippocampal circuit. Analysis of the trajectory of these transient changes suggested time-shifted cascades of plasticity from the dominant sensorimotor system to the contralateral hippocampus. In the cranial corticospinal tracts, changes in myelin-sensitive metrics during training in the posterior limb of the internal capsule were of greater magnitude in those who trained their upper limbs vs. lower limb trainees. Motor skill learning is associated with waves of grey and white matter plasticity, across a broad sensorimotor network.

Repeated assessment of key clinical walking measures can induce confounding practice effects.

Accurate functional outcome measures are critical for both clinical trials and routine patient assessments. Many functional outcomes improve with test repetition, a phenomenon that can confound the findings of longitudinal assessments. In this viewpoint, we tackle the poorly considered issue of practice effects in prevailing clinical walking tests based on current literature, while also presenting the original data from our own work, in which we investigated practice effects in the timed 25-foot walk (T25FW), timed-up and go (TUG), and 2-minute walk test (2MWT). In these tests, performed on 3 consecutive days in 10 patients with multiple sclerosis and 40 healthy controls, we observed significant practice effects in several established walking outcomes, including a 9.0% improvement in patients' TUG performance (p = 0.0146). Pre-training in these walking tests prior to baseline measurement may mitigate practice effects, thereby improving the accuracy and value of their repeated use in research and clinical settings.

Symptomatic tension pneumocephalus following Palacos® cranioplasty in a shunted patient.

Tension pneumocephalus is an exceedingly rare complication of cerebrospinal fluid diversion occurring after surgery, trauma or spontaneous fistula formation. We report a case in a patient with a ventriculoperitoneal shunt who developed symptomatic tension pneumocephalus via a skin defect within 24 hours of undergoing bone cement cranioplasty.

Sigmund Freud-early network theories of the brain.

Since the early days of modern neuroscience, psychological models of brain function have been a key component in the development of new knowledge. These models aim to provide a framework that allows the integration of discoveries derived from the fundamental disciplines of neuroscience, including anatomy and physiology, as well as clinical neurology and psychiatry. During the initial stages of his career, Sigmund Freud (1856-1939), became actively involved in these nascent fields with a burgeoning interest in functional neuroanatomy. In contrast to his contemporaries, Freud was convinced that cognition could not be localised to separate modules and that the brain processes cognition not in a merely serial manner but in a parallel and dynamic fashion-anticipating fundamental aspects of current network theories of brain function. This article aims to shed light on Freud's seminal, yet oft-overlooked, early work on functional neuroanatomy and his reasons for finally abandoning the conventional neuroscientific "brain-based" reference frame in order to conceptualise the mind from a purely psychological perspective.

Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models.

Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs.

Fast demographic traits promote high diversification rates of Amazonian trees.

The Amazon rain forest sustains the world's highest tree diversity, but it remains unclear why some clades of trees are hyperdiverse, whereas others are not. Using dated phylogenies, estimates of current species richness and trait and demographic data from a large network of forest plots, we show that fast demographic traits--short turnover times--are associated with high diversification rates across 51 clades of canopy trees. This relationship is robust to assuming that diversification rates are either constant or decline over time, and occurs in a wide range of Neotropical tree lineages. This finding reveals the crucial role of intrinsic, ecological variation among clades for understanding the origin of the remarkable diversity of Amazonian trees and forests.

Markedly divergent estimates of Amazon forest carbon density from ground plots and satellites.

AIM: The accurate mapping of forest carbon stocks is essential for understanding the global carbon cycle, for assessing emissions from deforestation, and for rational land-use planning. Remote sensing (RS) is currently the key tool for this purpose, but RS does not estimate vegetation biomass directly, and thus may miss significant spatial variations in forest structure. We test the stated accuracy of pantropical carbon maps using a large independent field dataset. LOCATION: Tropical forests of the Amazon basin. The permanent archive of the field plot data can be accessed at: http://dx.doi.org/10.5521/FORESTPLOTS.NET/2014_1. METHODS: Two recent pantropical RS maps of vegetation carbon are compared to a unique ground-plot dataset, involving tree measurements in 413 large inventory plots located in nine countries. The RS maps were compared directly to field plots, and kriging of the field data was used to allow area-based comparisons. RESULTS: The two RS carbon maps fail to capture the main gradient in Amazon forest carbon detected using 413 ground plots, from the densely wooded tall forests of the north-east, to the light-wooded, shorter forests of the south-west. The differences between plots and RS maps far exceed the uncertainties given in these studies, with whole regions over- or under-estimated by > 25%, whereas regional uncertainties for the maps were reported to be < 5%. MAIN CONCLUSIONS: Pantropical biomass maps are widely used by governments and by projects aiming to reduce deforestation using carbon offsets, but may have significant regional biases. Carbon-mapping techniques must be revised to account for the known ecological variation in tree wood density and allometry to create maps suitable for carbon accounting. The use of single relationships between tree canopy height and above-ground biomass inevitably yields large, spatially correlated errors. This presents a significant challenge to both the forest conservation and remote sensing communities, because neither wood density nor species assemblages can be reliably mapped from space.

Extradural spinal cavernous malformation: a rare but important mimic.

Purely extradural spinal cavernous malformations (ESCMs) are rare, but the number of cases reported seems to be increasing. A 44-year-old woman presented with progressive cervicothoracic back pain, lower limb paraesthesia and hypertonia. MRI showed a well-circumscribed, convex lesion in the T1-4 extradural space causing cord compression and encroaching into the left T2/3 neural foramen. Selective spinal angiography demonstrated a vascular blush at the T2/T3 level corresponding with the mass. A feeding vessel arising from the base of the T1 spinous process was identified and successfully catheterised, but embolisation was precluded by unfavourable anatomy of the posterior spinal artery. At hemilaminectomy, the lesion was found to be an ESCM. The patient went on to make a full recovery. We reviewed 71 cases of ESCM reported in the last decade. Incidence of ESCM is unclear; the largest case series reported on nine patients, but most published accounts were single case studies. Patients presented with back pain (33%), myelopathy (56%) and/or radiculopathy (39%). Onset of symptoms was usually insidious over months to years, but 30% presented with sudden-onset neurological symptoms, often due to spontaneous haemorrhage. Mean age at diagnosis was 44 (range, 2-74; SD, 19.6) years with a 1:1 sex ratio. Lesions were found at all levels except C1-C2, but a strong predilection for the dorsal thoracic spine (68%) was shown. The lesion extended into an intravertebral foramen in at least 24 cases (34%). MRI is the investigation of choice, and angiography of ESCM has rarely been described. Most (87%) were hypo- to isointense on T1 MRI while hyperintensity on T2 (91%) and avid (89%), usually homogenous gadolinium update was almost universal. Perilesional haemosiderin, characteristic of intracranial and intramedullary cavernous malformation was rarely seen. In many cases, meningioma or nerve sheath tumour was misdiagnosed prior to surgery. All patients underwent total (95%) or subtotal (5%) microsurgical resection with excellent results; all improved (23%) or recovered fully (77%) after surgery. Those who presented acutely did worse; 38% had residual deficits.

mRNA vaccine development during the COVID-19 pandemic: a retrospective review from the perspective of the Swiss affiliate of a global biopharmaceutical company.

The coronavirus disease 2019 (COVID-19) pandemic has been the defining public health emergency of our time. In Switzerland, messenger RNA (mRNA) vaccines were and still are widely utilized as a critical component of the Federal Office of Public Health (FOPH)'s preventative mitigation strategy. The development, conditional approval and worldwide roll-out of mRNA vaccines against COVID-19 proceeded at an unprecedented pace and presented myriad challenges for manufacturers. In this review, we discuss, from the perspective of the Swiss affiliate of a global biopharmaceutical company, the clinical, regulatory, pharmacovigilance and logistical considerations of making a mRNA COVID-19 vaccine available to the Swiss population during a pandemic as rapidly as possible while ensuring strict adherence to safety and quality standards.

Corticospinal Control of a Challenging Ankle Task in Incomplete Spinal Cord Injury.

After incomplete spinal cord injury (iSCI), the control of lower extremity movements may be affected by impairments in descending corticospinal tract function. Previous iSCI studies demonstrated relatively well-preserved movement control during simple alternating dorsiflections and plantar flexions albeit with severely reduced motor strength and range of motion. This task, however, required comparably limited fine motor control, impeding the sensitivity to assess the modulatory capacity of corticospinal control. Therefore, we introduced a more challenging ankle motor task necessitating complex and dynamic feedback-based movement adjustments to modulate corticospinal drive. Nineteen individuals with iSCI and 22 control subjects performed two different ankle movement tasks: (1) a regular, auditory-guided ankle movement task at a constant frequency as baseline assessment and (2) an irregular, visually guided ankle movement task following a pre-defined trajectory as a more challenging motor task. Both tasks were performed separately and in a randomized order. Electromyography (EMG) and kinematic data were recorded. The EMG frequency characteristics were investigated using wavelet transformations. Control participants exhibited a shift of relative EMG intensity from higher (>100 Hz) to lower frequencies (20-60 Hz) comparing the regular with the irregular movement task. There is evidence that EMG activity within these lower frequencies comprise information on corticospinal drive. The EMG frequency shift was less pronounced for the less impaired leg and absent for the more impaired leg of individuals with iSCI. The precision error during the irregular task was significantly higher for individuals with iSCI (more impaired leg: 12.34 ± 11.14%; less impaired leg: 6.93 ± 2.74%) compared with control participants (4.10 ± 0.84%). These results, along with the walking performance, correlated well with the delta frequency shift between the regular and irregular movement task in the 38 Hz band (corticospinal drive frequency) in the iSCI group, suggesting that task performance is related to the capacity to modulate corticospinal control. The irregular movement task holds promise as a tool for revealing further insights into corticospinal control of single-joint movements. It may serve as a surrogate marker for the assessment of modulatory capacity and the integrity of corticospinal control in individuals with iSCI early after injury and throughout rehabilitation.

Joint-level responses to tofacitinib and methotrexate: a post hoc analysis of data from ORAL Start.

BACKGROUND: Rheumatoid arthritis (RA) has a variable impact on different synovial joints, with inflammation being more commonly observed in some joints than others. Emerging evidence suggests that the anatomical variation in pathophysiology could result in differential responses to treatments across the joints, both within and between modes of action. This analysis aimed to characterize joint-specific responses to tofacitinib and methotrexate monotherapy in patients with RA. METHODS: This was a post hoc analysis of data from the phase III trial ORAL Start (NCT01039688), in methotrexate-naïve patients with RA. A paired joint pathology score (PJPS), derived from bilateral tender/swollen joint counts, was calculated. The percentage change from baseline in PJPS (%∆PJPS) and treatment-specific responses (tofacitinib 5 and 10 mg twice daily [BID] vs methotrexate; tofacitinib 5 vs 10 mg BID) for each patient joint pair, except for those with baseline/post-baseline PJPS = 0, were calculated at month 3, month 6, and month 12. Radiographic progression was similarly assessed using the Modified Total Sharp Score at month 6 and month 12. RESULTS: In methotrexate-naïve patients, differences in %∆PJPS demonstrated greater responses with tofacitinib vs methotrexate in most joint locations. Lesser responses with tofacitinib vs methotrexate were observed in most joints of the feet, particularly at month 12. Despite this, radiographic progression at month 12 was significantly worse in the foot (and metacarpophalangeal) joints of patients receiving methotrexate vs tofacitinib. CONCLUSION: We observed variation in joint-specific responses with tofacitinib and methotrexate monotherapy. Despite a proximal-distal efficacy gradient, with better clinical responses in the feet, patients receiving methotrexate monotherapy demonstrated more radiographic progression in the foot joints compared with those receiving tofacitinib. These findings suggest that body site- and therapy-specific characteristics may interact to produce differential treatment responses. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01039688.

Prognosis of walking function in multiple sclerosis supported by gait pattern analysis.

BACKGROUND: Walking impairment is a common and highly disabling symptom in people with MS (PwMS). Ambulatory deterioration is poorly characterized in PwMS and reliable prognosis that may guide clinical decisions is elusive. This study aimed to objectively track the progression of clinical walking performance and kinematic gait patterns in PwMS over 4 years, thereby revealing potential prognostic markers for deterioration of ambulatory function. METHODS: Twenty-two PwMS (48.8 ± 9.9 years, 14 females; expanded disability status scale [EDSS]: 4.5 ± 0.9 points) with gait impairments were recruited at the University Hospital Zurich, Switzerland. Gait function was monitored over a period of 4 years using a set of standardized clinical walking tests (timed 25-foot walk [T25FW], 6 min walk test [6MWT], 12-item MS walking scale [MSWS-12]) and comprehensive 3D kinematic gait analysis. Walking decline was assessed in the full patient cohort and in patient sub-groups that were built according to MS type (relapsing-remitting [RRMS], progressive [PMS]) and subjects' pathological gait signature (cluster groups 1-3). RESULTS: In the total cohort (n = 22), we found a significant worsening in the 6MWT (BL vs. 4y: -41.1 m; P = 0.0053), while the performance in the T25FW, MSWS-12 and the EDSS remained unchanged over 4 years. Subjects with PMS (n = 12) showed a significant worsening in the EDSS (BL vs. 4y: +0.6 points; P = 0.0053), which was not observed in participants with RRMS (n = 10). Whereas deterioration of clinical walking function was not different between subjects with RRMS and PMS, we identified differences in clinical walking deterioration between PwMS with varying gait pattern pathologies: Subjects with spastic-paretic gait impairments (cluster 1; n = 9) demonstrated a marked worsening in the T25FW (BL vs. 4y: +2 s; P = 0.0020) and 6MWT (BL vs. 4y: -92.9 m; P < 0.0001) which was not seen in PwMS with an ataxia-like (cluster 2; n = 8) or unstable walking pattern (cluster 3; n = 5). Deterioration of clinical walking performance in cluster 1 was accompanied by a specific worsening of gait deficits that were characteristic of this cluster at baseline, a phenomenon not found in the other sub-groups. Accordingly, aggravation of cluster 1-specific gait impairments over 4 years predicted deterioration of the 6MWT in the total cohort (n = 22) with an accuracy of 90.9% (sensitivity: 90.9%; specificity: 90.9%; Nagelkerkes coefficient of determination R2: 0.721), unveiling key determinants of MS-related walking decline. CONCLUSIONS: Our findings highlight the potential of quantitative, functional outcomes for objective tracking of disease progression in PwMS. Gait pattern analysis can provide valuable information on the underlying pathomechanisms of gait deterioration and may represent a complementary prognostic tool for walking function in PwMS. CLINICAL TRIAL: clinicaltrials.gov, NCT01576354.

Inclusive Trial Designs in Acute Spinal Cord Injuries: Prediction-Based Stratification of Clinical Walking Outcome and Projected Enrolment Frequencies.

BACKGROUND: New therapeutic approaches in neurological disorders are progressing into clinical development. Past failures in translational research have underlined the critical importance of selecting appropriate inclusion criteria and primary outcomes. Narrow inclusion criteria provide sensitivity, but increase trial duration and cost to the point of infeasibility, while broader requirements amplify confounding, increasing the risk of trial failure. This dilemma is perhaps most pronounced in spinal cord injury (SCI), but applies to all neurological disorders with low frequency and/or heterogeneous clinical manifestations. OBJECTIVE: Stratification of homogeneous patient cohorts to enable the design of clinical trials with broad inclusion criteria. METHODS: Prospectively-gathered data from patients with acute cervical SCI were analysed using an unbiased recursive partitioning conditional inference tree (URP-CTREE) approach. Performance in the 6-minute walk test at 6 months after injury was classified based on standardized neurological assessments within the first 15 days of injury. Functional and neurological outcomes were tracked throughout rehabilitation up to 6 months after injury. RESULTS: URP-CTREE identified homogeneous outcome cohorts in a study group of 309 SCI patients. These cohorts were validated by an internal, yet independent, validation group of 172 patients. The study group cohorts identified demonstrated distinct recovery profiles throughout rehabilitation. The baseline characteristics of the analysed groups were compared to a reference group of 477 patients. CONCLUSION: URP-CTREE enables inclusive trial design by revealing the distribution of outcome cohorts, discerning distinct recovery profiles and projecting potential patient enrolment by providing estimates of the relative frequencies of cohorts to improve the design of clinical trials in SCI and beyond.

Effect of dose adjustments on the efficacy and safety of tofacitinib in patients with rheumatoid arthritis: a post hoc analysis of an open-label, long-term extension study (ORAL Sequel).

INTRODUCTION/OBJECTIVES: We assess the impact of switching versus staying on the same tofacitinib dose on efficacy and safety in patients with rheumatoid arthritis (RA). METHODS: ORAL Sequel was an open-label, long-term extension study of patients with RA receiving tofacitinib 5 or 10 mg BID for up to 9.5 years. Tofacitinib doses could be switched during the study at investigator discretion. In this post hoc analysis, data from ORAL Sequel were stratified into four groups: 5 → 10 mg BID (Dose-up); 5 mg BID (Stay-on 5); 10 → 5 mg BID (Dose-down); and 10 mg BID (Stay-on 10). Efficacy assessments over 12 months included: change from baseline in 4-component Disease Activity Score in 28 joints, erythrocyte sedimentation rate (DAS28), and DAS28 minimum clinically important difference, remission, and low disease activity (LDA) rates. Safety was assessed for the study duration. RESULTS: Generally, DAS28 improvements and minimum clinically important difference rates were significantly greater (p < 0.05) in Dose-up versus Stay-on 5 up to month 12. DAS28 remission rates were significantly greater in Dose-up versus Stay-on 5 at month 12. Change from baseline in DAS28 was similar in Dose-down and Stay-on 10. No significant differences in DAS28 LDA rates were observed between groups. Safety data were similar overall across the four groups. CONCLUSION: In patients with RA receiving open-label tofacitinib, this analysis found that some benefited from increasing dose from 5 to 10 mg BID and did not find that reducing dose from 10 to 5 mg BID affected efficacy or that dose switching in either direction affected safety. STUDY REGISTRATION: ClinicalTrials.gov number NCT00413699. Registered December 20, 2006. https://clinicaltrials.gov/ct2/show/NCT00413699 Key Points • This post hoc analysis of data from the long-term extension study, ORAL Sequel, assessed the impact of dose switching between tofacitinib 5 and 10 mg twice daily (BID), at the investigator's discretion, on efficacy and safety in patients with rheumatoid arthritis (RA). • Dosing up from tofacitinib 5 to 10 mg BID was associated with improved efficacy up to 12 months versus staying on 5 mg BID, and dosing down from 10 to 5 mg BID was not generally associated with a significant loss of efficacy. • Safety outcomes were generally consistent across dose groups and did not change markedly after switching dose in either direction. • These findings can help to inform physicians on what may be expected in terms of efficacy and safety when adjusting tofacitinib dose according to clinical need. The recommended tofacitinib dosage for the treatment of RA in most jurisdictions is 5 mg BID.

Tools and methodologies to support more sustainable biofuel feedstock production.

Increasingly, government regulations, voluntary standards, and company guidelines require that biofuel production complies with sustainability criteria. For some stakeholders, however, compliance with these criteria may seem complex, costly, or unfeasible. What existing tools, then, might facilitate compliance with a variety of biofuel-related sustainability criteria? This paper presents four existing tools and methodologies that can help stakeholders assess (and mitigate) potential risks associated with feedstock production, and can thus facilitate compliance with requirements under different requirement systems. These include the Integrated Biodiversity Assessment Tool (IBAT), the ARtificial Intelligence for Ecosystem Services (ARIES) tool, the Responsible Cultivation Areas (RCA) methodology, and the related Biofuels + Forest Carbon (Biofuel + FC) methodology.

Prospective comparative study of intraoperative balloon electronic brachytherapy versus resection with multidisciplinary adjuvant therapy for recurrent glioblastoma.

BACKGROUND: Intraoperative balloon electronic brachytherapy (IBEB) may provide potential benefit for local control of recurrent cerebral glioblastomas (GBMs). METHODS: This is a preliminary report of an open-label, prospective, comparative cohort study conducted in two neurosurgical centers with ongoing follow-up. At recurrence, patients at one center (n = 15) underwent reresection with IBEB while, at the second center (n = 15), control subjects underwent re-resection with various accepted second-line adjuvant chemoradiotherapy options. A comparative analysis of overall survival (OS) and local progression-free survival (LPFS) following re-resection was performed. Exploratory subgroup analysis based on postoperative residual contrast-enhanced volume status was also done. RESULTS: In the IBEB group, median LPFS after re-resection was significantly longer than in the control group (8.0 vs. 6.0 months; log rank χ2 = 4.93, P = 0.026, P < 0.05). In addition, the median OS after second resection in the IBEB group was also significantly longer than in the control group (11.0 vs. 8.0 months; log rank χ2 = 4.23, P = 0.04, P < 0.05). CONCLUSION: These hypothesis-generating results from a small cohort of subjects suggest putative clinical benefit in OS and LPFS associated with maximal safe re-resection of recurrent GBM with IBEB versus re-resection and standard adjuvant therapy, a hypothesis that deserves further testing in an appropriately powered clinical trial.

Drought-mortality relationships for tropical forests.

*The rich ecology of tropical forests is intimately tied to their moisture status. Multi-site syntheses can provide a macro-scale view of these linkages and their susceptibility to changing climates. Here, we report pan-tropical and regional-scale analyses of tree vulnerability to drought. *We assembled available data on tropical forest tree stem mortality before, during, and after recent drought events, from 119 monitoring plots in 10 countries concentrated in Amazonia and Borneo. *In most sites, larger trees are disproportionately at risk. At least within Amazonia, low wood density trees are also at greater risk of drought-associated mortality, independent of size. For comparable drought intensities, trees in Borneo are more vulnerable than trees in the Amazon. There is some evidence for lagged impacts of drought, with mortality rates remaining elevated 2 yr after the meteorological event is over. *These findings indicate that repeated droughts would shift the functional composition of tropical forests toward smaller, denser-wooded trees. At very high drought intensities, the linear relationship between tree mortality and moisture stress apparently breaks down, suggesting the existence of moisture stress thresholds beyond which some tropical forests would suffer catastrophic tree mortality.

Targeted Walking in Incomplete Spinal Cord Injury: Role of Corticospinal Control.

Locomotor recovery after incomplete spinal cord injury (iSCI) is influenced by spinal and supraspinal networks. Conventional clinical gait analysis fails to differentiate between these components. There is evidence that corticospinal control is enhanced during targeted walking, where each foot must be continuously placed on visual targets in randomized order. This study investigates the potential of targeted walking in the functional assessment of corticospinal integrity. Twenty-one controls and 16 individuals with chronic iSCI performed normal and targeted walking on a treadmill while electromyograms (EMGs) and kinematics were recorded. Precision (% of accurate foot placements) in targeted walking was significantly lower in individuals with iSCI (82.9 ± 14.7%, controls: 94.9 ± 4.0%). Although the overall kinematic pattern was comparable between walking conditions, controls showed significantly higher semitendinosus (ST) activity before heel-strike during targeted walking. This was accompanied by a shift of relative EMG intensity from 90-120 Hz to lower frequencies of 20-60 Hz, previously associated with corticospinal control of muscle activity. Targeted walking in individuals with iSCI evoked smaller EMG changes, suggesting that the switch to more corticospinal control is impaired. Accordingly, mildly impaired iSCI individuals revealed higher adaptations to the targeted walking task than more-impaired individuals. Recording of EMGs during targeted walking holds potential as a research tool to reveal further insights into the neuromuscular control of locomotion. It also complements findings of pre-clinical studies and is a promising novel surrogate marker of integrity of corticospinal control in individuals with iSCI and other neurological impairments. Future studies should investigate its potential for diagnosis or tracking recovery during rehabilitation.

Characterizing cognitive-motor impairments in patients with myotonic dystrophy type 1.

Myotonic Dystrophy Type 1 (DM1) is the most frequent hereditary, adult-onset muscular dystrophy. Nevertheless, DM1-associated cognitive-motor impairments have not been fully characterized so far. This study aimed at profiling cognitive and locomotor dysfunctions in these patients. In addition, cognitive-motor interactions were assessed using a dual-task paradigm. Comprehensive cognitive-motor impairment profiles were generated for 19 patients with DM1 and 19 healthy subjects by thorough clinical, biomechanical and neuropsychological examinations. Detailed gait analysis was performed using a 3D motion capture system, whereas cognitive function was assessed using a standardized neuropsychological test battery. Patients with DM1 showed impaired functional mobility, gait velocity and endurance. DM1-related gait pathology was mainly characterized by enhanced dynamic instability, gait variability, and restricted ankle dorsiflexion. Patients' cognitive impairments particularly concerned attentional functions. Dual-task conditions induced gait deviations that slightly differed between patients and controls. DM1-associated cognitive impairments correlated with reduced functional mobility and impaired ankle dorsiflexion. Patients with DM1 revealed significant impairments of walking function, balance and cognitive performance. Differential cognitive-motor interference and significant interactions between cognitive and motor dysfunctions point towards a prominent role of cognition in gait performance of patients with DM1.

Familiarization with treadmill walking: How much is enough?

Treadmill-based gait analysis is widely used to investigate walking pathologies and quantify treatment effects on locomotion. Differential sensorimotor conditions during overground vs. treadmill walking necessitate initial familiarization to treadmill walking. Currently, there is no standardized treadmill acclimatization protocol and insufficient familiarization potentially confounds analyses. We monitored initial adaptations to treadmill walking in 40 healthy adults. Twenty-six walking parameters were assessed over 10 minutes with marker-based kinematic analysis and acclimatization profiles were generated. While 16 walking parameters demonstrated initial acclimatization followed by plateau performance, ten parameters remained stable. Distal lower limb control including ankle range of motion, toe trajectory and foot clearance underwent substantial adaptations. Moreover, intralimb coordination and gait variability also demonstrated acclimatization, while measures of symmetry and interlimb coordination did not. All parameters exhibiting a plateau after acclimatization did so within 6-7 minutes (425 strides). Older participants and those naïve to treadmill walking showed adaptations with higher amplitudes but over similar timescales. Our results suggest a minimum of 6 minutes treadmill acclimatization is required to reach a stable performance, and that this should suffice for both older and naïve healthy adults. The presented data aids in optimizing treadmill-based gait analysis and contributes to improving locomotor assessments in research and clinical settings.