Differences in motor unit behavior during isometric contractions in patients with diabetic peripheral neuropathy at various disease severities.

Abstract

The aim of this study was to determine whether HD-sEMG is sensitive to detecting changes in motor unit behavior amongst healthy adults and type 2 diabetes mellitus (T2DM) patients presenting diabetic peripheral neuropathy (DPN) at different levels. Healthy control subjects (CON, n=8) and T2DM patients presenting no DPN symptoms (ABS, n=8), moderate DPN (MOD, n=18), and severe DPN (SEV, n=12) performed isometric ankle dorsiflexion at 30% maximum voluntary contraction while high-density surface EMG (HD-sEMG) was recorded from the tibialis anterior muscle. HD-sEMG signals were decomposed, providing estimates of discharge rate, motor unit conduction velocity (MUCV), and motor unit territory area (MUTA). As a result, the ABS group presented reduced MUCV compared to CON. The groups with diabetes presented significantly larger MUTA compared to the CON group (p<0.01), and the SEV group presented a significantly lower discharge rate compared to CON and ABS (p<0.01). In addition, the SEV group presented significantly higher CoVforce compared to CON and MOD. These results support the use of HD-SEMG as a method to detect peripheral and central changes related to DPN.