Elsevier

Gait & Posture

Volume 62, May 2018, Pages 463-467
Gait & Posture

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

https://doi.org/10.1016/j.gaitpost.2018.04.001Get rights and content

Highlights

  • Balance instability occurs due to weakness of the specific muscles of the foot.

  • The plantar flexor muscles are important for the maintenance of functional activities.

  • Postural instability is greater in the anterior-posterior direction with closed eyes.

Abstract

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; plantarflexors-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.

Introduction

Charcot-Marie-Tooth (CMT) disease is part of a group of genetically determined neuropathies with an estimated prevalence of 1:2500 and is the most prevalent hereditary neuropathy [1]. Most CMT cases can be classified into two main categories depending on the nature of the primary injury to the nerve fiber: CMT type 1 (CMT1), demyelinating pattern, presents motor conduction velocities in the upper limbs of less than 38 m/s, or CMT type 2 (CMT2), axonal pattern, which presents motor conduction velocities of more than 38 m/s. Barreto et al. [2] in a systematic review of epidemiological studies on CMT found the frequency of the main subtypes varied between 37.6 to 84% for CMT1, and 12 to 35.9% for CMT2.

Despite the great genetic heterogeneity of the disease, the phenotypes of the different CMT subtypes are similar [3]. In all forms, degeneration of the sensory and motor nerve fibers cause atrophy and muscle weakness, associated with loss of sensation, especially in the distal segments of the lower limbs [4]. The intrinsic muscles of the feet and legs are affected early in the disease, impacting balance and mobility [[5], [6]].

One sequela found in CMT disease is gait change, which is typically influenced by muscle weakness and sensory impairments [7]. In the most severe form of CMT disease respiratory disorders, such as the compromised maximum expiratory pressure (PEMax) observed in individuals with CMT2 by Garcez et al. (2015), may be present [8].

In the literature many authors note disorders of balance and functionality of patients with CMT [[4], [9], [10]]. They highlight muscle weakness and loss of proprioception as the main causes [4]. However, there is no consensus among the authors about how these variables affect balance and functionality. The focus of this study was to evaluate individuals with CMT2 in an attempt to understand how loss of strength interferes in balance and function.

Section snippets

Sample and ethical consideration

An observational cross-sectional study was conducted through anamnesis (personal data, main complaint, history of current and past illness and family history) and kinesiological-functional evaluation (assessment of tendon reflexes, muscle tone, muscular strength, static and dynamic balance and functionality) of individuals with CMT2 belonging to the same multigenerational family, in the city of Tobias Barreto, Sergipe, Brazil. All measurements were performed with the patient barefoot without

Results

The sample comprised a group of 15 adult subjects with CMT2 disease (CMT2G), 8 females, and 7 males (age: 31.33 ± 13.41, height: 158.33 ± 7 cm, weight: 56.14 ± 8.16), who underwent a neurophysiological investigation as described by Neves and Kok [9], and a control group (CG) of 15 healthy subjects matched by age and gender with the CMT2 group (age: 29.53 ± 12.88, height: 172.07 ± 10, weight: 70.10 ± 12.73). There was no significant difference between the CMT2G and CG in terms of body mass index

Discussion

The evaluation of lower limb muscle strength, balance and functionality demonstrated changes in individuals with CMT type 2 when compared to individuals without CMT. These findings have already been described in the literature. The purpose of this study was to clarify how motor changes compromise balance and functionality in individuals with CMT disease.

This study demonstrated that muscle weakness of the plantarflexor, dorsiflexor, invertor and evertor muscles was related to greater

Conclusion

In the present study, individuals with CMT2 presented less strength, poorer balance and less functional performance when compared to healthy individuals. The findings of this study allow us to conclude that, initially, when CMT is mild, balance instability occurs mainly due to weakness of the dorsiflexor and plantar flexor muscles of the foot: It is no coincidence that the initial signs and symptoms of the disease also stem from the weakness of these muscles. It is suggested that with the

Limitations of the study

The main limitation of the study was to find patients available to make the evaluations, because it is a rarer type of CMT. In addition, the variability of the clinical aspects presented by individuals with CMT hinders the understanding and more solid conclusions about the disease.

Acknowledgments

The authors wish to acknowledge the support of the Charcot–Marie–Tooth Association of Tobias Barreto in the undertaking of this research.

References (20)

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    Overall, people with HMSN show a relatively low gait speed (Newman et al., 2007), shortened step length (Don et al., 2007b) and enlarged step width (Don et al., 2007b; Nonnekes et al., 2021) compared to persons without impairments. In addition, postural instability during standing (de França Costa et al., 2018; Lencioni et al., 2014; van der Linden et al., 2010) and walking (de França Costa et al., 2018; Don et al., 2007b; Newman et al., 2007; Sabir and Lyttle, 1984), and increased risk of falling (Eichinger et al., 2016; Ramdharry et al., 2011) have been reported. To improve postural stability during standing and walking, orthopedic footwear is commonly prescribed to people with HMSN (Postema et al., 2018, 1991).

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