A new system can detect the worsening of hand function over time in people with Charcot-Marie-Tooth disease (CMT), researchers in Italy have found.
Their study, titled “Characteristics and Evolution of the Charcot-Marie-Tooth Hand: an Observational Study,” was published in the European Medical Journal.
Symptoms affecting hands and/or feet are common in people with CMT. However, because it is a rare condition, studies on hand function over time are scarce, which makes it difficult to design rehabilitation strategies for these patients. Also, validated methods to assess hand skills are still lacking, and the ones that exist have limitations.
Therefore, a team at the University of Genova, in Italy, evaluated a novel method to measure hand function, which they dubbed the Hand Test System, or HTS.
“Because hand dysfunction is an important problem for the quality of life of CMT patients, innovative tools for its evaluation are strongly needed,” the researchers wrote.
HTS consists of engineered gloves that measure hand dexterity and are connected to a computer. Individuals in the study, with their eyes closed, put the gloves on and moved their hands according to instructions — for instance, tapping fingers in a particular order as quickly as possible. These movements were then analyzed by the computer and, based on the readings, inferences were made about hand function.
The study included 105 people with CMT, all tested at the San Martino Policlinico Hospital. Each participant had their hand function measured three times, each measurement taken six months apart, so that the researchers could look for changes over time. In addition to HTS, the team also used established ways to measure hand function, such as the Sollerman hand function test and the thumb opposition test.
The results confirmed that, at baseline, people with CMT had hand function impairments compared with previously studied healthy controls. Over 20 months, HTS was the only method to detect significant worsening of hand function. A specific task found progressive impairment in both dominant (decrease from 3.5 to 2.9 Hz) and non-dominant (5.0 to 2.7 Hz) hands.
These findings suggest that the intrinsic muscles of the hand (those completely within the hand) are impaired earlier and more severely than the flexor muscles, which extend from the hand to the arm.
“This study confirms that impairment of the hands is common in CMT patients,” the scientists wrote. “Importantly, the authors’ longitudinal evaluation suggests that HTS is a responsive tool to evaluate the hand function … probably more sensitive than other outcome measures.”
The team plans to test HTS in more patients and over a longer period to validate these results.