A randomized trial of scapular exercises with electromyography biofeedback in oral cancer patients with accessory nerve dysfunction

Abstract Purpose: This study aims to investigate the effects of electromyography (EMG) biofeedback on scapular positions and muscle activities during scapular-focused exercises in oral cancer patients with accessory nerve dysfunction.Methods: Twenty-four participants were randomly allocated to the motor-control with biofeedback group (N=12) or the motor-control group (N=12) immediately after neck dissection. Each group performed scapular-focused exercises with conscious control of scapular orientation for three months. EMG biofeedback of upper trapezius (UT), middle trapezius (MT), and lower trapezius (LT) were provided in the motor-control with biofeedback group. Scapular symmetry measured by modified lateral scapular slide test; shoulder pain; active range of motion (AROM) of shoulder abduction; upper extremity function; maximal isometric muscle strength of UT, MT, and LT; and muscle activities during arm elevation/lowering in the scapular plane were evaluated at baseline and the end of the intervention.Results: After the 3-month intervention, only the motor-control with biofeedback group showed improving scapular symmetry. Although both groups did not show significant improvement in shoulder pain, increased AROM of shoulder abduction and muscle strength of the UT and MT were observed in both groups. In addition, only the motor-control with biofeedback group had improved LT muscle strength, upper extremity function, and reduced UT and MT muscle activations during arm elevation/lowering.Conclusions: Early interventions for scapular control training significantly improved shoulder mobility and trapezius muscle strength. Furthermore, by adding EMG biofeedback to motor-control training, oral cancer patients demonstrated greater effectiveness in stabilizing scapular position, muscle efficiency, and upper extremity function than motor-control training alone.Trial registration: Institutional Review Board: This study was approved by the Chang Gung Medical Foundation Institutional Review Board (Approval No: 201901788A3. Approval Date: 2 January, 2020). Clinical trial Registration: This trial was registered at ClinicalTrials.gov (ClinicalTrials.gov ID: NCT04476004. Initial released Date: 16 July, 2020).