Analysis of motor axonal damage in carpal tunnel syndrome using MScanFit MUNE

Using a motor unit number estimation (MUNE) method, MScanFit MUNE enables simple, fast, noninvasive, and automated analysis of the number of motor units in patients.

To investigate the validity of the MScanFit MUNE method (number of motor units) against the compound muscle action potential method (compound amplitude of motor units) at identifying of motor axonal damage in carpal tunnel syndrome, particularly in the early stages, thereby providing a basis for timely treatment and surgical intervention.

Electrophysiological data were collected from 170 hands of 128 patients with different stages of carpal tunnel syndrome. A further 30 healthy subjects were included. Observe the motor axonal damage at different stages.

Compound amplitude of motor units and MScanFit MUNE values were used to analyze differences in motor axonal damage between the mild, moderate, severe patient groups, and control group. Plot the ROC curves for diagnosing carpal tunnel syndrome using the two methods.

The mean MScanFit MUNE values for the mild, moderate, and severe groups were 79.4 ± 19.2, 55.2 ± 17.9, and 27.4 ± 11.7, respectively. The compound amplitude of motor units for these groups were 6.5 ± 2.4 mV, 5.2 ± 2.9 mV, and 3.1 ± 1.7 mV, respectively. The values for both methods were lower in the severe group than in the mild and moderate groups (p < 0.05). The MScanFit MUNE values were lower in the mild group than in the control group (p < 0.05), whereas this difference was not observed in another method. The respective areas under the ROC curves for diagnosis were 0.78 for compound amplitude of motor units and 0.86 for MScanFit MUNE.

The MScanFit MUNE method is more effective in identifying motor axonal damage at different stages of carpal tunnel syndrome, especially in the early stages.