Myoelectric motor execution and sensory training to treat chronic pain and paralysis in a replanted arm: a case study

Following upper limb amputation, surgeries such as arm transplantation or replantation might be an option to restore function. After such surgeries, rehabilitation of the arm is needed. However, conventional rehabilitation is dependent on some volitional movement of the arm. If there is no or minimal movement of the arm, conventional rehabilitation might not be successful. The purpose of this study is to evaluate a novel combination of myoelectric motor execution (MME) and sensory training (ST) to reduce pain and improve upper limb function in a person with a highly impaired replanted arm.

The participant, a 72-year-old male, had his right arm replanted after a traumatic accident. No functional recovery was achieved following conventional rehabilitation and chronic neuropathic pain developed post-surgery. The participant then received 18 sessions of MME in which intended movements were decoded from the replanted arm's myoelectric signals using machine learning and real-time feedback was provided on a screen. Nine sessions included ST using tactile grids where the participant discriminated different sensations.

The participant regained active extension of the thumb (4 degrees) and regained active wrist movement (flex: 6 degrees, extend: 10 degrees), both of which had no active movement prior the MME interventions. He also perceived an increase in sensation in the thumb and fingers. Pain levels fluctuated throughout the study and no consistent change could be concluded.

MME is a novel virtual rehabilitation treatment which provides feedback using virtual limbs and serious games. MME combined with ST is a potential rehabilitation treatment for individuals with highly impaired arms and hands which might ameliorate chronic neuropathic pain.