Abstract
We investigated the use of surface electromyography with biofeedback for telerehabilitation. The aim was to investigate the therapist's point of view, and the general acceptability of the system for the patient and for the therapist. The system allowed a therapist to modulate the rehabilitation protocol remotely, by changing the configuration variables, e.g. threshold and duration. The case study focused on a patient with arm impairment following a stroke. After two weeks of daily usage, there were some differences between the patient and the therapist about the ease of use of the equipment. However, there was general agreement about the usefulness of the system, ease of the performed tasks, appropriateness of the performed tasks and overall opinion. Wireless technology would reduce the complexity of the tasks required of the patient.
Introduction
During rehabilitation in hospital, a patient is instructed by a therapist to perform certain physical exercises. During the rest of the day, the patient tries to repeat the physical exercises previously performed with the therapist. In this phase the therapist has no control of the patient while some information, mainly related to physical activity, could be useful for better modulating a patient's treatment. In this context, surface electromyography is considered valuable for quantitative evaluation of muscle activity. 1,2
We have investigated the use of surface electromyography with biofeedback for telerehabilitation. The aim of the study was to investigate the therapist's point of view. The secondary aim was to investigate the general acceptability of the system, for the patient and for the therapist.
Methods
The case study focused on a patient with arm impairment following a stroke. The outcome measures for functioning were based on the Action Research Arm test (ARA), which has a range 0–57. The patient was aged 59 years and had an ARA score of 41. The study did not require ethics approval.
The system used in the study was a commercial portable surface electromyograph (Mytron VD11, SATEM, Rome) which used audio biofeedback. 3 Its small size (158 × 95 × 45 mm) and long battery life, made it suitable for the present study (Figure 1). The system was part of a client/server application, 4 which allowed remote configuration of all system variables (e.g. duration, threshold type and values). It also permitted acquisition, visualization and storage of the surface electromyograph signals related to physical exercise.
The surface electromyography unit
The system block diagram is shown in Figure 2. The configuration files and exercise sessions are stored in the internal memory of the device. The data can be transferred to the laptop, which is connected to the therapist's workstation by the hospital LAN.
System architecture. The surface electromyography unit was connected to the laptop with an RS 232 cable. The other connections were wireless
The system compares the acquired signal with a pre-set threshold, and evaluates muscle activation and muscle relaxation. The greater the difference between the measured signal and the threshold, the more audio feedback is provided (i.e. at higher amplitude and frequency).
The occupational therapist first trained the patient to use the system. The patient was then free to use the system for defined rehabilitation exercises during the day, in addition to the traditional treatment. The exercise protocol was based on a set of isometric contractions performed during grasping, object lifting, resisted brachial biceps actions and a set of relaxation movements to be executed after previous exercise. The patient needed to perform the following tasks:
Connect and disconnect the electrodes. To simplify this task the therapist marked the correct position for the electrodes using temporary tattoo paint; Connect the electromyograph to the laptop computer by using the supplied cable. This allowed the new configuration file from the therapist's workstation to be stored in the device, and also allowed the information about the exercises performed to be transmitted to the therapist.
Once a day the therapist analysed the entire dataset and modified the biofeedback system variables, according to the patient's progress.
After two weeks of treatment, the therapist was asked to report their point of view in using the system by using the SWOT (Strengths, Weaknesses, Opportunities, Threats) framework, which is a common management technique for decision-making. 5 A survey was also conducted to assess the general acceptability for both patient and therapist. The survey focused on five aspects: ease of use, usefulness of the system, ease of the performed tasks, appropriateness of the performed tasks and general opinion. Each aspect was scored using a scale ranging from 1 = very bad to 5 = excellent.
Results
The therapist reported the following relating to use of the system:
Strengths
The capability of letting the patient train when they wanted to during the day after the traditional rehabilitative session;
More patients could be treated at the same time, by quantitatively monitoring their physical performance. It would be possible to manage multiple patients;
The patient was motivated to perform additional rehabilitation exercises by having direct feedback about performance. The patient considered the treatment to be highly personalized.
Weaknesses
The system showed poor software and hardware usability, mainly because it often required on-site therapist intervention;
The tasks for the patient were too complex for practical use. The difficulties were mainly associated with the special cable connecting the electromyograph and the laptop computer;
The electromyograph had a restricted number of electrodes for monitoring patient activity.
Opportunities
After suitable modification, the equipment could treat multiple patients simultaneously;
Treatment could be further personalized to suit the individual status of the patient.
Threats
Organizational procedures in the hospital were not adequate for managing the large quantities of information that the system could produce;
Dedicated training was required for therapists.
The survey results are shown in Table 1. The differences between the patient and the therapist about using the system were mainly concerned with its ease of use. There was general consensus on the other four aspects.
Results from the general acceptability survey. The values shown are scores on the scale ranging from 1 = very bad to 5 = excellent
After two weeks of treatment, the patient showed a slight improvement in the ARA test, but there were no significant differences with respect to the baseline.
Discussion
Most telerehabilitation applications are designed to treat patients at home, after an initial phase in hospital. 6 We have designed a telerehabilitation system for use in hospital. The experience of the present pilot study was based on a system prototype. A larger study with people in various stages of stroke disease will be needed to evaluate the clinical effectiveness and organizational impact of the system by direct comparison with traditional treatment.
Nonetheless, the results of the present study were encouraging. There were positive aspects of the work, although there were also negative aspects, mainly related to the ease of use of the system. Wireless technology would reduce the complexity of the tasks for the patient.