TY - JOUR AB - BACKGROUND: During split-belt treadmill walking, neurotypical humans exhibit adaptations characterized by a gradual decrease in step length asymmetry (SLA) toward or beyond symmetry, whereas individuals with cerebellar damage do not show these motor adaptations. Neuromusculoskeletal simulations may help to better understand individual aspects of the underlying neural control, but are currently incapable of predicting adaptations to the continuous perturbations imposed by split-belt walking. METHODS: We extend a spinal reflex model with a biologically inspired model of the cerebellum, which enables error-based motor adaptation by modulating spinal control parameters in response to mismatches between a continuously updated internal prediction and actual motor outcomes. In this work, the cerebellum modulates only a single spinal control parameter, the timing of swing initiation in each leg, which allows examining its isolated contribution to gait adaptation as all other reflex pathways are held constant. We created 80 s predictive simulations of the model walking on a split-belt treadmill with a 2:1 belt-speed ratio, and compared predicted spatiotemporal parameters and kinematics to the reflex-only model and literature. RESULTS: The reflex-only model could walk on the split-belt treadmill, but showed no step length adaptations. In contrast, the extended model adapted SLA from an initial asymmetric value toward symmetry or beyond, following an exponential time course similar to that observed in experiments. The model could adapt at varying rates and converge to different asymmetry levels. We found that, in simulation, SLA adaptation during split-belt walking is possible without changes in reflex gains, by adapting the timing of swing initiation. The modulation of timing alone also predicted the experimentally observed exponential adaptation in the temporal domain, but only a linear change in the spatial domain, indicating that additional control mechanisms are likely required to reproduce the full spatial adaptation observed in split-belt walking. CONCLUSION: We propose a computational model of the cerebellum which, when integrated into a spinal reflex model, autonomously drives feedforward gait adaptations during split-belt walking. This advances the current state of predictive simulations and may eventually help to better understand specific adaptation processes. The modular framework can be extended to test different hypotheses about motor control and adaptation during continuous perturbation tasks. AU - Fleischmann, S.* AU - Shanbhag, J.* AU - Miehling, J.* AU - Wartzack, S.* AU - Ong, C.-N.* AU - Eskofier, B.M. AU - Koelewijn, A.D.* C1 - 76161 C2 - 58441 TI - A model of the cerebellum generates gait adaptations in a reflex-based neuromusculoskeletal model during split-belt walking. JO - J. NeuroEng. Rehabil. VL - 22 IS - 1 PY - 2025 SN - 1743-0003 ER - TY - JOUR AB - BACKGROUND: Hereditary spastic paraplegias (HSPs) comprise a group of genetic movement disorders characterized by progressive spasticity and weakness of the lower limbs leading to gait deficits. Instrumented gait measures are applied to quantify gait patterns in HSP objectively. However, there is no consensus on the most relevant HSP-specific digital outcome measures for future clinical studies. AIM: This systematic review aims to summarize outcome measures of instrumented gait analysis in HSP patients, focusing on both traditional motion capture (MOCAP) and inertial sensor systems. METHODS: Following PRISMA-2020 guidelines, a comprehensive literature search was conducted in PubMed, Scopus, and Web of Science to identify studies using instrumented gait analysis in HSP. Data on participant characteristics, measurement systems, outcome measures, results, and risk of bias were systematically extracted. RESULTS: In total, 38 studies published between 2004 and 2024, including 29 observational studies and 9 interventional studies, met the inclusion criteria. Various gait parameters were used, including spatio-temporal, kinematic, kinetic, and electromyography (EMG) parameters. Walking speed and range-of-motion (ROM) knee were identified as important parameters for differentiating HSP patients from healthy controls, but these parameters are more general rather than disease-specific. Foot lift, ROM foot, and gait variability are promising, more disease-specific parameters, as they reflect disease severity and increased balance deficits. However, a deeper understanding of all gait parameter categories is necessary, particularly for the upper body. Few studies explored sub-cohorts that exhibit different HSP gait characteristics. CONCLUSION: While MOCAP provides valuable data in controlled hospital environments, there is a need for validated mobile sensor systems capturing the gait patterns of HSP patients in real-life without supervision. Future research must focus on better longitudinal multicenter studies with larger sample sizes to establish robust digital outcomes and monitor disease progression and therapeutic response in HSP. AU - Koch, V.* AU - Ibrahim, A.* AU - Winkler, J.* AU - Eskofier, B.M. AU - Regensburger, M.* AU - Gassner, H.* C1 - 74876 C2 - 57647 CY - Campus, 4 Crinan St, London N1 9xw, England TI - Outcome measures of instrumented gait analysis in hereditary spastic paraplegia: A systematic review. JO - J. NeuroEng. Rehabil. VL - 22 IS - 1 PB - Bmc PY - 2025 SN - 1743-0003 ER -