The influence of Task-Related Training combined with Transcutaneous Electrical Nerve Stimulation on paretic upper limb muscle activation in patients with chronic stroke

OBJECTIVES: This study investigated the efficacy of Task-Related Training (TRT) Combined with Transcutaneous Electrical Nerve Stimulation (TENS) on the improvement of upper limb muscle activation in chronic stroke survivors with mild or moderate paresis. METHODS: A single-blind, randomized clinical trial was conducted with 46stroke survivors with chronic paresis. They were randomly allocated two groups: the TRT+ TENS group (n = 23) and the TRT+ placebo TENS (TRT+ PLBO) group (n = 23). The TRT+ TENS group received 30 minutes of high-frequency TENS on wrist and elbow extensors, while the TRT+ PLBO group received placebo TENS that was not real ES. Both groups did 30 minutes of TRT after TENS application. Intervention was given five days a week for four weeks. The primary outcomes of upper limb muscle activation were measured by integrated EMG (IEMG), a digital manual muscle tester for muscle strength, active range of motion (AROM) and Fugl-Meyer Assessment of the upper extremity (FMA-UE). The measurements were performed before and after the 4 weeks intervention period. RESULTS: Both groups demonstrated significant improvements of outcomes in IEMG, AROM, muscle strength and FMA-UE during intervention period. When compared with the TRT+ PLBO group, the TRT+ TENS group showed significantly greater improvement in muscle activation (wrist extensors, P = 0.045; elbow extensors, P = 0.004), muscle strength (wrist extensors, P = 0.044; elbow extensors, P = 0.012), AROM (wrist extension, P = 0.042; elbow extensors, P = 0.040) and FMA-UE (total, P < 0.001; shoulder/elbow/forearm, P = 0.001; wrist, P = 0.002; coordination, P = 0.008) at the end of intervention. CONCLUSIONS: Our findings indicate that TRT Combined with TENS can improve paretic muscle activity in upper limb paresis, highlighting the benefits of somatosensory stimulation from TENS.