Key determinants of impaired gait performance in adults with neuromuscular diseases: a multiparametric and multimodal analysis.

Neuromuscular diseases (NMD) are associated with gait impairments affecting the quality of life. Contributing factors such as the severity of muscle weakness or kinematics alterations have mostly been studied separately. Therefore, the key determinants of impaired gait in patients with NMD remain unclear. This work aimed at investigating the major determinants of gait impairments through the assessment of muscle weakness, lower limb kinematic, muscle activation, and spatiotemporal parameters within a single session in patients and controls. Patients with NMD and controls were studied. After assessing maximal voluntary strength, subjects underwent a 2-min walk test (2MWT) while recording electromyography, kinematics, perceived exertion, dyspnea, and pain using verbal scales. A penalized regression was used to identify the main contributing variable to impaired gait performance and to build a predictive model for validation; 28 with NMD and 17 controls were included. Eight major features of 2MWT gait performance were identified by the model: toe-off, stride length, step duration, cadence, ankle angle at foot strike, knee extensors strength, and timing variability in hip flexion-extension. The LASSO model provided accurate estimation of gait performance with 5.4% of average absolute error and 0.89 of R2. Substantial alterations in muscle activation patterns and lower limb kinematics were found in patients compared with controls. This study provides insights regarding the gait impairments in patients with NMD. Identified determinants can guide targeted interventions to improve gait and quality of life. More research with larger cohorts and diverse conditions is needed to confirm and broaden these findings.NEW & NOTEWORTHY This is the first study aiming to identify the key determinants of impaired gait in patients with neuromuscular diseases using a comprehensive approach. Lower limb muscle activation, joint kinematics, spatiotemporal gait parameters, strength capacity and perceived stability, exertion, dyspnea, and pain were measured during a single gait session. Using a penalized regression model, 8 major determinants were identified among the 74 assessed. Delayed toe-off time was identified as the factor with the greatest relative importance.