Effects of Electromyographic Visual Feedback for Spinal Accessory Nerve Dysfunction After Neck Dissection

Patients with head and neck cancer and undergo neck dissection often suffer from spinal accessory nerve dysfunction (e.g. shoulder droop, shoulder pain, and decreased active range of motion (AROM) of the shoulder joint and scapular muscle strength), even the spinal accessory nerve is preserved during surgery. Abnormal muscle activities of scapular muscles, including upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), serratus anterior (SA) and rhomboid were reported in subsequent research articles. Particularly for the trapezius muscle, the decreased amplitudes were observed even after 9 months of neck dissection. It has been reported that conscious correction of scapular orientation during arm movement could increase trapezius muscle activities, and motor control training could change scapular kinematic such as increased posterior tilt and upward rotation during arm movement. The aim of this study is to explore the effects of electromyographic (EMG) visual feedback on scapular muscle activities and strength in oral cancer survivors with spinal accessory nerve dysfunction. Investigators will recruit 60 newly diagnosed oral cancer subjects through the plastic surgeon's referral from January 2020 to February 2021. The participants will be randomized separated into experimental or control group. Each group would receive regular physical therapy for shoulder function (e.g. transcutaneous electrical stimulation, shoulder joint range of motion exercise) and scapular-focused exercise. EMG visual feedback would be combined with scapular-focused exercise.