Evaluation of muscle strength, balance and functionality of individuals with type 2 Charcot-Marie-Tooth Disease

Background: Charcot-Marie-Tooth (CMT) disease is part of a group of genetically determined neuropathies. The intrinsic muscles of the feet and legs are affected early in the disease, impacting balance and mobility. Research question: The purpose of this study was to evaluate individuals with type 2 Charcot-Marie-Tooth disease to understand how motor changes interfere in balance and function. Methods: The sample comprised 15 individuals with CMT2 from the same family (CMT2G) and a control group (CG) of healthy individuals matched for age and gender. The CMT individuals were classified using the Charcot-Marie-Tooth Neuropathy Score (CMTNS). Muscle strength of the ankle was assessed using a manual dynamometer. Balance was measured using a stabilometer and Berg's Balance Scale (BBS). Functional performance was measured by the Timed Up and Go Test (TUG). Results: There was a statistically significant difference between the CMT2G and the CG for right side (RS) and left side (LS) muscle strength (dorsiflexors-RS and LS: p < 0,0001; invertors-RS and LS: p < 0.0001; plantar-flexors-RS: p < 0.0001; plantarflexors-LS: p = 0.0019; evertors-RS: p = 0.0016; evertors-LS: p < 0.0001) in the parameters for the velocity and displacement of center of pressure (CoP) anterior-posterior (AP) in the stabilometry tests with eyes open (EO) and closed (EC) (VCoPAP-EO and VCoPAP-EC: p = 0.0123; DCoPAP-OE: p = 0.0183 and DCoPAP-EC: p = 0.0129), the Berg Balance Scale (p = 0.0066) and the TUG test (p = 0.0003). Significance: Thus when the severity of the disease is mild the instability is caused by the weakness of the dorsiflexors and plantarflexors. In patients considered moderate/severe, in addition to weakness of the leg muscles, loss of proprioception will contribute to impaired balance.