Hans Rietman

Myoelectric forearm prostheses: State of the art from a user-centered perspective

User acceptance of myoelectric forearm prostheses is currently low. Awkward control, lack of feedback, and difficult training are cited as primary reasons. Recently, researchers have focused on exploiting the new possibilities offered by advancements in prosthetic technology. Alternatively, researchers could focus on prosthesis acceptance by developing functional requirements based on activities users are likely to perform. In this article, we describe the process of determining such requirements and then the application of these requirements to evaluating the state of the art in myoelectric forearm prosthesis research. As part of a needs assessment, a workshop was organized involving clinicians (representing end users), academics, and engineers. The resulting needs included an increased number of functions, lower reaction and execution times, and intuitiveness of both control and feedback systems. Reviewing the state of the art of research in the main prosthetic subsystems (electromyographic [EMG] sensing, control, and feedback) showed that modern research prototypes only partly fulfill the requirements. We found that focus should be on validating EMG-sensing results with patients, improving simultaneous control of wrist movements and grasps, deriving optimal parameters for force and position feedback, and taking into account the psychophysical aspects of feedback, such as intensity perception and spatial acuity.

Gait in children with cerebral palsy : observer reliability of Physician Rating Scale and Edinburgh Visual Gait Analysis Interval Testing scale

The aim of this study was to test the inter- and intraobserver reliability of the Physician Rating Scale (PRS) and the Edinburgh Visual Gait Analysis Interval Testing (GAIT) scale for use in children with cerebral palsy (CP). Both assessment scales are quantitative observational scales, evaluating gait. The study involved 24 patients ages 3 to 10 years (mean age 6.7 years) with an abnormal gait caused by CP. They were all able to walk independently with or without walking aids. Of the children 15 had spastic diplegia and 9 had spastic hemiplegia. With a minimum time interval of 6 weeks, video recordings of the gait of these 24 patients were scored twice by three independent observers using the PRS and the GAIT scale. The study showed that both the GAIT scale and the PRS had excellent intraobserver reliability but poor interobserver reliability for children with CP. In the total scores of the GAIT scale and the PRS, the three observers showed systematic differences. Consequently, the authors recommend that longitudinal assessments of a patient should be done by one observer only.

Lower limb amputation Part 2: Rehabilitation - a 10 year literature review

Ten years after the ISPO consensus conference on amputation surgery, a search of relevant publications in the Rehabilitation-prosthetics-literature over the years 1990–2000 was performed. The main key-words in this research were: “lower limb, amputation, human and rehabilitation”. One hundred and four (104) articles were assessed by reading and from these the authors selected 24 articles. These articles are summarised, under several subheadings in this review article, focussing especially on quality of life, functional outcome and predictive factors.

Quality of Life After Sentinel Lymph Node Biopsy or Axillary Lymph Node Dissection in Stage I/II Breast Cancer Patients: A Prospective Longitudinal Study

BackgroundBreast cancer patients’ quality of life (QoL) after surgery has been reported to improve significantly over time. Little is known about QoL recovery after sentinel lymph node biopsy (SLNB) in comparison to axillary lymph node dissection (ALND).Methods175 of 195 stage I/II breast cancer patients completed the EORTC QLQ-C30: one day before surgery (T0) and after 6 (T1), 26 (T2), 52 (T3) and 104 (T4) weeks. Of these, 54 patients underwent SLNB, 56 SLNB+ALND and 65 ALND. General linear models and paired T-tests between T0–T4 and T1–T4 were computed. Complications, radiotherapy and systemic therapy were added to the model.ResultsSignificant time effects were found on physical, role and emotional functioning. Physical and role functioning decreased between T0 and T1. At T4, SLNB patients’ functioning had increased to their T0 level; ALND (+/– SLNB) patients’ functioning had increased, but had not improved to T0 level. Emotional functioning increased linearly between T0 and T4. At T4, emotional functioning was significantly higher in all groups as compared with T0. No significant group or interaction (time × group) effects were found. Complications and chemotherapy had a significant negative effect on role, emotional and cognitive functioning. Complications had a significant effect on social functioning also. Effect sizes varied between 0.00 and 0.06.ConclusionTwo years post surgery, breast cancer patients’ QoL is comparable to that shortly before surgery. Women rated their emotional functioning as even better. SLNB is not associated with a better QoL than ALND. However, undergoing systemic therapy and/or experiencing complications affects QoL negatively.

Vibrotactile grasping force and hand aperture feedback for myoelectric forearm prosthesis users

Background: User feedback about grasping force and hand aperture is very important in object handling with myoelectric forearm prostheses but is lacking in current prostheses. Vibrotactile feedback increases the performance of healthy subjects in virtual grasping tasks, but no extensive validation on potential users has been performed. Objectives: Investigate the performance of upper-limb loss subjects in grasping tasks with vibrotactile stimulation, providing hand aperture, and grasping force feedback. Study design: Cross-over trial. Methods: A total of 10 subjects with upper-limb loss performed virtual grasping tasks while perceiving vibrotactile feedback. Hand aperture feedback was provided through an array of coin motors and grasping force feedback through a single miniature stimulator or an array of coin motors. Objects with varying sizes and weights had to be grasped by a virtual hand. Results: Percentages correctly applied hand apertures and correct grasping force levels were all higher for the vibrotactile feedback condition compared to the no-feedback condition. With visual feedback, the results were always better compared to the vibrotactile feedback condition. Task durations were comparable for all feedback conditions. Conclusion: Vibrotactile grasping force and hand aperture feedback improves grasping performance of subjects with upper-limb loss. However, it should be investigated whether this is of additional value in daily-life tasks. Clinical relevance This study is a first step toward the implementation of sensory vibrotactile feedback for users of myoelectric forearm prostheses. Grasping force feedback is crucial for optimal object handling, and hand aperture feedback is essential for reduction of required visual attention. Grasping performance with feedback is evaluated for the potential users.

Dutch evidence-based guidelines for amputation and prosthetics of the lower extremity: Rehabilitation process and prosthetics. Part 2

Background: A structured, multidisciplinary approach in the rehabilitation process after amputation is needed that includes a greater focus on the involvement of both (para)medics and prosthetists. There is considerable variation in prosthetic prescription concerning the moment of initial prosthesis fitting and the use of replacement parts. Objectives: To produce an evidence-based guideline for the amputation and prosthetics of the lower extremities. This guideline provides recommendations in support of daily practice and is based on the results of scientific research and further discussions focussed on establishing good medical practice. Part 2 focuses on rehabilitation process and prosthetics. Study design: Systematic literature design. Methods: Literature search in five databases and quality assessment on the basis of evidence-based guideline development. Results: An evidence-based multidisciplinary guideline on amputation and prosthetics of the lower extremity. Conclusion: The best care (in general) for patients undergoing amputation of a lower extremity is presented and discussed. This part of the guideline provides recommendations for treatment and reintegration of patients undergoing amputation of a lower extremity and can be used to provide patient information. Clinical relevance This guideline provides recommendations in support of daily practice and is based on the results of scientific research and further discussions focussed on establishing good medical practice.

Dutch evidence-based guidelines for amputation and prosthetics of the lower extremity: Amputation surgery and postoperative management. Part 1

Background: Surgeons still use a range of criteria to determine whether amputation is indicated. In addition, there is considerable debate regarding immediate postoperative management, especially concerning the use of ‘immediate/delayed fitting’ versus conservative elastic bandaging. Objectives: To produce an evidence-based guideline for the amputation and prosthetics of the lower extremities. This guideline provides recommendations in support of daily practice and is based on the results of scientific research and further discussions focussed on establishing good medical practice. Part 1 focuses on amputation surgery and postoperative management. Study design: Systematic literature design. Methods: Literature search in five databases. Quality assessment on the basis of evidence-based guideline development. Results: An evidence-based multidisciplinary guideline on amputation and prosthetics of the lower extremity. Conclusion: The best care (in general) for patients undergoing amputation of a lower extremity is presented and discussed. This part of the guideline provides recommendations for diagnosis, referral, assessment, and undergoing amputation of a lower extremity and can be used to provide patient information. Clinical relevance This guideline provides recommendations in support of daily practice and is based on the results of scientific research and further discussions focussed on establishing good medical practice.

Feasibility of error-based electrotactile and auditive feedback in prosthetic walking.

Background and aim: Several studies have shown that feedback in upper-leg prostheses is possible, but slow or difficult to interpret. In this study, electrotactile and auditive error-based feedback, only giving feedback when an undesired event occurs, were tested for its use in upper-leg prosthesis when provided during a perturbation. Technique: A total of nine healthy subjects walked on a prosthetic simulator which was disturbed at the end of the swing phase. They received either no feedback, electrotactile feedback, or auditive feedback at the time of the perturbation. Discussion: The reaction time of the subjects only improved by 40 ms when using auditory feedback, compared to the no-feedback condition. No changes in reaction time were found in the electrotactile feedback condition. Considering perturbation detection was not taken into account in this study, this improvement is not enough for practical applications in upper-leg prosthesis. Clinical relevance Many transfemoral amputees are insecure about their prosthesis, are afraid of falling, or actually fall. Providing feedback specifically during a perturbation may prevent them from falling, or at least give them a chance to react.

Pushing the Limits: A Novel Tape Spring Pushing Mechanism to be Used in a Hand Orthosis

A device that supports hand function may significantly improve the quality of life of patients with muscular weakness. Since tight constraints such as size and weight are placed upon the device, complexity of the hardware and functional performance should be carefully balanced. A novel force transmission mechanism based on tape springs is presented for use in a hand orthosis. The actuator force is transmitted to the finger by a system consisting of a tape spring, two slider blocks and an end stop per finger. The tape spring allows for bending in one direction, and resists bending in the other direction. A prototype with the new mechanism is constructed. The low profile together with the ability to transmit large forces makes this mechanism suitable for hand orthoses.

Hoofdstuk 10 Amputatie en prothesiologie van de onderste extremiteit

Het amputeren van een voet, onderbeen of bovenbeen is voor veel chirurgen een teleurstellende ingreep, omdat de amputatie gezien wordt als het resultaat van (eigen) medische falen. Voor veel patienten met een vasculaire aandoening en soms ook met een oncologische aandoening, betekent een amputatie afscheid nemen van (een deel van) het been, maar ook afscheid nemen van een leefpatroon met veel pijn en problemen.