Gait pattern classification may assist in clinical decision making and cluster analysis (CA) has been often adopted to this aim. The goal of this study was to identify, through CA, typical walking patterns in a group of 21 young subjects with CMT1A, a hereditary progressive neuropathy, and to study possible correlation with the disease's clinical status. The protocol included kinematic/ kinetic analysis of natural walking and more demanding locomotor tasks, i.e. toe-and heelwalking. Hierarchical cluster analysis was carried out on parameters related to primary signs (footdrop and push-off deficit) and, separately, to compensatory mechanisms at proximal (pelvis, hip and knee) or distal (ankle) level.CA on primary signs during natural walking identified three clusters: (1) pseudo-normal patients (PN), not significantly different from controls; (2) patients showing only foot-drop (FD); (3) patients with foot-drop and push-off deficit (FD&POD). Patients belonging to the PN subgroup showed distal abnormalities during heel-walking. The FD&POD subgroup was associated to a significantly worse clinical score (CMTES, p < 0.05). The main compensatory strategies, which occurred independently from primary clusterization, included augmented hip/knee flexion in swing (steppage) and early ankle plantarflexion at mid stance (vaulting). We concluded that, although a number of young CMT1A patients do not show typical primary deviations during natural walking, they do show significant abnormalities in more demanding locomotor tasks that should be therefore considered. It is also hypothesized that progression of this degenerative condition may be associated to the migration of patients to more severe clusters, with possible appearance of compensatory strategies.

Some neurodegenerative diseases at early stage may not drastically affect basic gait ability, whereas more demanding locomotor tasks are more prone to disease-induced abnormalities. In this study, we evaluated the interday test–retest reliability, 4–6 weeks apart, of instrumented movement analysis on a group of 20 subjects with Charcot–Marie–Tooth (CMT) disease considering a set of kinematic and kinetic curves and related parameters obtained during natural walking (NW) and faster walking, heel and toe-walking, step ascending and descending.Results showed that the reliability was good for NW, with the exception of trunk curves, pelvic tilt and EMG profiles (moderate reliability), and trunk ROM in sagittal/transverse plane (poor reliability). Comparing our results with literature, CMT patients did not present a greater variability during NW than healthy subjects or patients with diseases of CNS. Additional locomotor tasks showed a slight reduction of reliability, although the moderate-to-good level shown in NW was almost never reduced to poor. Most of SEM values (absolute measurement errors) were smaller than 5°, a clinically acceptable threshold. In particular THS, an ankle joint related parameter computed across heel and toe-walking tasks, showed an optimal reliability (ICC = 0.95, SEM = 2.7°) and correlation with CMT clinical scores. Toe and heel-walking and step ascending tasks maximised the number of parameters with a moderate-to-good correlation with patients’ clinical status. We concluded that, in addition to natural walking, more challenging locomotor tasks are good candidates to provide reliable and sensitive outcome measures for CMT patients.

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Charcot-Marie-Tooth (CMT) disease is the most common inherited neuromuscular disorder, presenting with symptoms often occurring since childhood, and showing a progressive course. At present, there are no valid and reliable measures for evaluation of impairment and disability in the pediatric population. The aim of this study was to determine the usefulness of outcome measures, commonly used in adult patients, in CMT children. We report the results of a comprehensive evaluation of 21 children affected with CMT type 1A, including clinical examinations, measure of hand and foot muscle strength with a hand-held dynamometer, and the following scales: CMT Neuropathy Score or its clinical component CMT Examination Score, Overall Neuropathy Limitations Scale (ONLS), Walk-12 questionnaire, and nine-hole peg test (9-HPT). Hand grip, three-point pinch, and foot dorsiflexion strength were significantly lower than age/sex equivalent in almost all cases. 9-HPT was significantly abnormal in 62% of patients and CMT Examination Score was <10 points in all cases. ONLS showed presence of minor disability in the upper limbs in 57% and mild abnormalities of gait in 71% of patients. Overall, these scales demonstrated limited potential to measure disability and severity of the disease confirming that it is necessary to identify specific scales for children with CMT.