Often prosthesis users abandon their devices due to difficulties in prosthesis control and lack of motivation to train. To properly control a prosthesis, amputation patients must learn how to activate, isolate and sustain nerve signals to the muscles left at the stump. Results of clinical validations show that game-based training leads to an improvement in clinical parameters for prosthesis control and patient engagement.
Relevance: Many users of a myoelectric arm prosthesis do not use their device because they find it too difficult to control the prosthesis. This may be due to the fact that patients cannot contract their muscles in the residual limb in a sufficiently controlled manner. Exactly this circumstance is trained during the physiotherapy with the patients. But at home many patients lack the motivation to continue the exercises from physiotherapy. Mobile games on the smartphone can provide patients with long-term motivation to continue the repetitive exercises that prepare the muscles for controlling a prosthesis at home. Aim: The aim of this study is to support patients in training at home with a game on their smartphone. This should increase motivation and improve the ability to control a prosthesis efficiently. Design: The Smartphone App is a rhythmic, music-based game consisting of different game modes. It has not only a display for real-time bio-feedback, but also many other audiovisually motivating incentives to continue playing the game. Similar to the classical control of a commercial prosthesis, the muscle signals are measured by two surface electrodes and, in this case, transferred to the app instead of the prosthesis. With these 2 electrodes the game is controlled. Test persons receive feedback on their performance through the constantly displayed bio-feedback, but also through high scores of the various levels and user statistics. By testing the muscle coordination twice a week, the neuromuscular improvements in the control of the game can be monitored. Method/Procedure: Eight transradially (below the elbow) amputated patients participate in this study. The intervention consists of playing with the smartphone training program using the muscle signals picked up by surface electrodes. The study will run over a period of 5 weeks, with participants playing with the training program at home for 4 weeks. The program should be used 5 times per week, therefore the intervention takes place 20 times in total. In the 5th week the final assessment, a final evaluation and the return of the devices take place. All usage data, such as starting and exiting the program and the duration of use, are recorded by the program itself and treated anonymously.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
8
Training of the patient's muscle coordination, strength and ability to separately contract muscles, while holding up patient motivation. The patient is expected to follow a protocol of 4 weeks of training.
Medical University of Vienna, CD Laboratory for Restoration of Extremity Function
Vienna, Austria
RECRUITINGMaximum Voluntary Contraction
Testing the patients voluntary myoelectric (EMG) contraction strength, given in millivolt (mV). This assessment is used as a calibration of the voltage detected by the electrodes. Participants are asked to maximally contract one muscle and to hold this contraction for 1.3 seconds, of which only the last second is taken for calculating the activation baseline.
Time frame: 10 minutes
Precision Control
Testing the patient's ability to precisely control their muscle contraction, given in percentage of target deviation. The Assessment of Precision Control evaluates the participant's fine EMG control accuracy. The range of this test was adapted based on the outcome of the MVC test. The participant is asked to reach 30 randomly preselected activation levels in the range of 10-90% of maximum voluntary contraction, and sustain them for 300 milliseconds each. The required level of activation is indicated by a triangular mark on the EMG bar. A total of 30 marks (3 trials consisting of 10 levels) are performed. The percentile deviation from the mark is taken as outcome measure.
Time frame: 30 minutes
Endurance Control
The Assessment of Endurance Control assesses muscle coordination and muscle fatigue while the participants used their EMG signals to closely follow a sine curve o 1/4 hertz on the screen until they feel fatigued. The estimated force needed to reach the peaks of the sine curve corresponds to 60% maximum voluntary contraction. Electrode activation needs to be separate to reach the peaks of the sine curve. The minimum time to be reached in this test is 5 minutes. The outcome measure is the EMG signal deviation from the desired sine curve, given as correlation r².
Time frame: 15 minutes
Phantom limb pain
Evaluation if the patient's phantom limb pain has been alleviated during or after the intervention. A questionnaire will be given that includes questions from the MPI - German version of the Multidimensional Pain Inventory. Three parts of the inventory, comprised of 12 scales, examine the impact of pain on the patients' lives, the responses of others to the patients' communications of pain, and the extent to which patients participate in common daily activities. The outcome measure is a number that will represent the pain felt by the patient
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Time frame: At the beginning and at the end of the study (after 4 weeks)