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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.

Supplemental material, sj-pdf-1-nnr-10.1177_15459683231166937 for Walking Outcome After Traumatic Paraplegic Spinal Cord Injury: The Function of Which Myotomes Makes a Difference? by Adrian Cathomen, Doris Maier, Jiri Kriz, Rainer Abel, Frank Röhrich, Michael Baumberger, Giorgio Scivoletto, Norbert Weidner, Rüdiger Rupp, Catherine R. Jutzeler, John D. Steeves, Armin Curt and Marc Bolliger in Neurorehabilitation and Neural Repair

Inertial Measurement Units (IMUs) have gained popularity in gait analysis and human motion tracking, and they provide certain advantages over stationary line-of-sight-dependent Optical Motion Capture (OMC) systems. IMUs appear as an appropriate alternative solution to reduce dependency on bulky, room-based hardware and facilitate the analysis of walking patterns in clinical settings and daily life activities. However, most inertial gait analysis methods are unpractical in clinical settings due to the necessity of precise sensor placement, the need for well-performed calibration movements and poses, and due to distorted magnetometer data in indoor environments as well as nearby ferromagnetic material and electronic devices. To address these limitations, recent literature has proposed methods for self-calibrating magnetometer-free inertial motion tracking, and acceptable performance has been achieved in mechanical joints and in individuals without neurological disorders. However, the performance of such methods has not been validated in clinical settings for individuals with neurological disorders, specifically individuals with incomplete Spinal Cord Injury (iSCI). In the present study, we used recently proposed inertial motion-tracking methods, which avoid magnetometer data and leverage kinematic constraints for anatomical calibration. We used these methods to determine the range of motion of the Flexion/Extension (F/E) hip and Abduction/Adduction (A/A) angles, the F/E knee angles, and the Dorsi/Plantar (D/P) flexion ankle joint angles during walking. Data (IMU and OMC) of five individuals with no neurological disorders (control group) and five participants with iSCI walking for two minutes on a treadmill in a self-paced mode were analyzed. For validation purposes, the OMC system was considered as a reference. The mean absolute difference (MAD) between calculated range of motion of joint angles was 5.00°, 5.02°, 5.26°, and 3.72° for hip F/E, hip A/A, knee F/E, and ankle D/P flexion angles, respectively. In addition, relative stance, swing, double support phases, and cadence were calculated and validated. The MAD for the relative gait phases (stance, swing, and double support) was 1.7%, and the average cadence error was 0.09 steps/min. The MAD values for RoM and relative gait phases can be considered as clinically acceptable. Therefore, we conclude that the proposed methodology is promising, enabling non-restrictive inertial gait analysis in clinical settings.

Supplemental material for Inclusive Trial Designs in Acute Spinal Cord Injuries: Prediction���Based Stratification of Clinical Walking Outcome and Projected Enrolment Frequencies by Adrian Cathomen, MSc, Laura Sirucek, MSc, Tim Killeen, PhD, Rainer Abel, MD, Doris Maier, MD, Norbert Weidner, MD, R��diger Rupp, PhD, Torsten Hothorn, PhD, John D. Steeves, PhD, Armin Curt, MD, and Marc Bolliger, PhD in Neurorehabilitation and Neural Repair

Additional file 1: Table S1. Extracted and chosen feature sets for recognition model generation. Table S2. Grid search results for neurons selection for different time windows and overlap rates as afunction of accuracy. Figure S1. Confusion matrices for all controls and two individuals with iSCI using LOPOCV.

Motivation: Compare and validate wearable sensor kinematic gait parameters with the existing gold standard. State of the art: • Experiment was based on known orientation and rotation in predefined speeds. • All the algorithms analysed showed reasonable results (delta rms errors < 6.4°) [1].

Supplemental material, MSJ845839_supplemental_material for Repeated assessment of key clinical walking measures can induce confounding practice effects by Christian Meyer, Tim Killeen, Lilla Lörincz, Armin Curt, Marc Bolliger, Michael Linnebank, Björn Zörner and Linard Filli in Multiple Sclerosis Journal