Study Identifies the Ideal Tests to Improve Clinical Evaluation of CMT1A Patients

A new study has evaluated and identified the best tests to use as outcome measures, which help doctors track patient progress or deterioration, for those with Charcot-Marie-Tooth disease type 1A. The study’s goal was to determine which outcome measures can help improve disease assessment both in clinical practice and in trials.

Titled “Outcome measures in the clinical evaluation of ambulatory Charcot Marie Tooth 1A subjects,” the study was published in the journal European Journal of Physical and Rehabilitation Medicine.

Charcot-Marie-Tooth disease (CMT) is a group of genetic diseases caused by mutations in genes that are important for the function of peripheral nerves, which control movement, sensation, and motor coordination.

The degeneration of peripheral nerves results in muscle atrophy, muscle weakness, and reduced sensation — including touch, heat, and cold — particularly in the body’s extremities such as the forearms, hands, lower legs, or feet.

Charcot-Marie-Tooth disease type 1 is the most common type, with subtype 1A being the most frequently observed.

Patients with CMT1A often complain of problems walking, joint tightness, deformities, and difficulties in sensing the body’s position and movement, called proprioception. 

To date, no definitive treatment is available for any of the Charcot-Marie-Tooth disease subtypes, and available therapies help only to manage symptoms.

Although new clinical trials testing investigational therapies are essential, measuring a patient’s outcomes in these studies is complicated by an inadequate number of validated measures.

Most clinical studies have measured outcomes using the Charcot‐Marie‐Tooth neuropathy score (CMTNS), which includes symptoms, signs, and neurophysiological tests.

However, a few recent studies have highlighted alternative scales that could improve the quantification of disease severity and changes in patient disability.

In this study, researchers sought to identify the most useful and sensitive outcome measures to clinically evaluate CMT1A patients.

The study was part of a larger clinical trial (NCT01289704) evaluating the efficacy and safety of an innovative rehabilitation protocol called TreSPE, which combines treadmill training, stretching, and respiratory and proprioceptive exercises. A pilot study suggested that this protocol is safe and improves patients’ balance and walking capability.

In the latest study, researchers compared several measures of walking ability and balance at baseline: the 10-meter walk test, the 6-minute walk test, the short physical performance battery (SPPB), the Berg balance scale (physical performance tests), and the walking impact scale, known as Walk-12. The standard CMTNS score and patient quality of life also were evaluated.

The study enrolled 53 patients with confirmed CMT1A diagnoses who were referred to one of four specialized neuropathy centers in Italy.

As anticipated, researchers found a strong correlation between the outcomes of walking and balance tests, which confirmed the usefulness of these tests in examining functional impairment in CMT1A patients.

Specifically, scientists observed that patients with better balance control also could walk faster and had fewer limitations on physical or motor skills.

This could be due to the fact that a patient’s ankle stability is affected by impairments in body structure, muscle strength, and their sense of movement and balance.

Overall, the study identified the 10-meter walk test, the 6-minute walk test, and the SPPB “as the most useful scales, in addition to the CMTNS, to evaluate the functional impairment of CMT1A patients who retain their walking capability.”

The findings are important for clinical practice, where “it is important to evaluate patients comprehensively but rapidly,” researchers wrote. 

Among the three tests, researchers suggest the use of SPPB “because of its rapidity to assess balance and gait disorders in clinical settings.”