EMG Pattern Recognition Control of the DEKA Arm: Impact on User Ratings of Satisfaction and Usability.

The DEKA Arm has multiple degrees of freedom which historically have been operated primarily by inertial measurement units (IMUs). However, the IMUs are not appropriate for all potential users; new control methods are needed. The purposes of this study were: 1) to describe usability and satisfaction of two controls methods-IMU and myoelectric pattern recognition (EMG-PR) controls-and 2) to compare ratings by control and amputation level. A total of 36 subjects with transradial (TR) or transhumeral (TH) amputation participated in the study. The subjects included 11 EMG-PR users (82% TR) and 25 IMU users (68% TR). The study consisted of in-laboratory training (Part A) and home use (Part B). The subjects were administered the Trinity Amputation and Prosthesis Experience satisfaction scale and other usability and satisfaction measures. Wilcoxon rank-sum tests compared the differences by control type. The differences were compared for those who did and did not want a DEKA Arm. The preferences for features of the DEKA Arm were compared by control type. The comparisons revealed poorer ratings of skill, comfort, and weight among EMG-PR users. The TR amputees using IMUs rated usability more favorably. TH amputees rated usability similarly. The TR amputees using EMG-PR were less satisfied with weight, pinch grip, and wrist display, whereas the TH amputees were less satisfied with the full system, wires/cables, and battery. Usability and satisfaction declined after Part B for EMG-PR users. Overall, we found that the IMU users rated the DEKA Arm and the controls more favorably than the EMG-PR users. The findings indicate that the EMG-PR system we tested was less well accepted than the IMUs for control of the DEKA Arm.

EMG pattern recognition compared to foot control of the DEKA Arm.

INTRODUCTION: EMG pattern recognition control (EMG-PR) is a promising option for control of upper limb prostheses with multiple degrees of freedom (DOF). The purposes of this study were to 1) evaluate outcomes of EMG-PR and inertial measurement units (IMU) control of the DEKA Arm as compared to personal prosthesis; and 2) compare outcomes of EMG-PR to IMU control of DEKA Arm. METHODS: This was a quasi-experimental, multi-site study with repeated measures that compared non-randomized groups using two types of controls: EMG-PR and IMUs. Subjects (N = 36) were transradial (TR) and transhumeral (TH) amputees. Outcomes were collected at Baseline (using personal prosthesis), and after in-laboratory training (Part A), and home use (Part B). Data was compared to personal prosthesis, stratified by amputation level and control type. Outcomes were also compared by control type. RESULTS: The EMG-PR group had greater prosthesis use after Part A, but worse dexterity, lower satisfaction, and slower activity performance compared to Baseline; the IMU group had slower activity performance. After Part B, the EMG-PR group had less perceived activity difficulty; the IMU group had improved activity performance, improved disability and activity difficulty, but slower performance. No differences were observed for TH group by control type in Part A or B. The TR group using EMG-PR had worse dexterity (Parts A & B), and activity performance (Part A) as compared to IMU users. DISCUSSION/CONCLUSION: Findings suggest that for the TR group that IMUs are a more effective control method for the DEKA Arm as compared to the EMG-PR prototypes employed in this study. Further research is needed to refine the EMG-PR systems for multi-DOF devices. Future studies should include a larger sample of TH amputees. TRIAL REGISTRATION: ClinicalTrials.gov NCT01551420.

The role of exercise testing in predicting successful ambulation with a lower extremity prosthesis: a systematic literature review and clinical practice guideline.

BACKGROUND: Growing discontent with the k-level system for functional classification of patients with limb loss and movement of healthcare toward evidence-based practice has resulted in the need for alternative forms of functional classification and development of clinical practice guidelines to improve access to quality prosthetic interventions. The purpose of this project was to develop and present a clinical practice recommendation for exercise testing in prosthetic patient care based on the results and synthesis of a systematic literature review. METHODS: Database searches of PubMed, Google Scholar, Web of Science, and Cochrane were conducted and articles reviewed. Of the potential 1386 articles 10 met the criteria for inclusion. These articles were assessed using the critical appraisal tool of the United Kingdom National Service Framework for Long-Term Conditions. Of the 10 included articles eight were of high, one of medium, and one of low, quality. Data from these articles were synthesized into 6 empirical evidence statements, all qualifying for research grade A. These statements were used to develop the proposed clinical practice guideline. RESULTS: While the results of this systematic review were not able to support the direct connection between cardiorespiratory performance and K-levels, the literature did support the ability of exercise testing results to predict successful prosthetic ambulation in some demographics. Both continuous maximum-intensity single lower extremity ergometer propelled by a sound limb and intermittent submaximal upper extremity ergometer protocols were found to be viable evaluation tools of cardiorespiratory fitness and function in the target population. CONCLUSION: The ability to sustain an exercise intensity of ≥50% of a predicted VO2max value in single leg cycle ergometry testing and achievement of a sustained workload of 30 W in upper extremity ergometry testing were found to be the strongest correlates to successful ambulation with a prosthesis. VO2 values were found to increase in amputee subjects following a 6-week exercise program. These synthesized results of the systematic literature review regarding exercise testing in patients with loss of a lower extremity were used to develop and a present a clinical treatment pathway.

Function, quality of life, and community integration of DEKA Arm users after discharge from prosthetic training: Impact of home use experience.

BACKGROUND:: Research on adaptation to advanced upper limb prostheses is needed. OBJECTIVES:: To (1) examine change in function, quality of life and community integration after prosthetic training, (2) determine whether change in outcomes varied by prosthesis complexity, and (3) compare patterns of change at 1 month for those who withdrew from the study and those who did not. STUDY DESIGN:: Quasi-experimental time series. METHODS:: Data were analyzed for 22 participants (18 completers). Performance and self-report outcome measures were collected after in-laboratory training (Part A) and every 4 weeks of home use (Part B). Outcomes from End of A to End of B were compared statistically. Outcomes across assessments and by configuration level were compared graphically. Changes in scores were compared graphically for completers and non-completers. RESULTS:: Quality of life scores did not change between End of A and End of B, whereas scores improved for one activity measure, two measures of self-reported function, and three dexterity measures ( p < 0.05). Outcomes of community integration, self-reported function, four dexterity measures, and one activity measure varied by prosthesis level. For participants who withdrew early, dexterity and activity scores worsened, perceived disability increased, and prosthesis satisfaction decreased after 4 weeks of home use. CONCLUSION:: Study completers adapted to the DEKA Arm. CLINICAL RELEVANCE: Findings suggest that for the majority of upper limb amputees discharged from prosthetic rehabilitation, function continues to improve with home use. However, a minority experience a decline in function, greater perceived disability, and greater dissatisfaction after 4 weeks, suggesting a need for continued therapy after intensive prosthetic training ends.

How do the outcomes of the DEKA Arm compare to conventional prostheses?

OBJECTIVES: Objectives were to 1) compare self-reported function, dexterity, activity performance, quality of life and community integration of the DEKA Arm to conventional prostheses; and 2) examine differences in outcomes by conventional prosthesis type, terminal device type and by DEKA Arm configuration level. METHODS: This was a two-part study; Part A consisted of in-laboratory training. Part B consisted of home use. Study participants were 23 prosthesis users (mean age = 45 ± 16; 87% male) who completed Part A, and 15 (mean age = 45 ± 18; 87% male) who completed Parts A and B. Outcomes including self-report and performance measures, were collected at Baseline using participants' personal prostheses and at the End of Parts A and B. Scores were compared using paired t-tests. Wilcoxon signed-rank tests were used to compare outcomes for the full sample, and for the sample stratified by device and terminal device type. Analysis of outcomes by configuration level was performed graphically. RESULTS: At the End of Part A activity performance using the DEKA Arm and conventional prosthesis was equivalent, but slower with the DEKA Arm. After Part B, performance using the DEKA Arm surpassed conventional prosthesis scores, and speed of activity completion was equivalent. Participants reported using the DEKA Arm to perform more activities, had less perceived disability, and less difficulty in activities at the End of A and B as compared to Baseline. No differences were observed in dexterity, prosthetic skill, spontaneity, pain, community integration or quality of life. Comparisons stratified by device type revealed similar patterns. Graphic comparisons revealed variations by configuration level. CONCLUSION: Participants using the DEKA Arm had less perceived disability and more engagement of the prosthesis in everyday tasks, although activity performance was slower. After home use experience, activity performance was improved and activity speed equivalent to using conventional prostheses.

Predictors of retention and attrition in a study of an advanced upper limb prosthesis: implications for adoption of the DEKA Arm.

PURPOSE: The purpose was to identify factors associated with completion of the VA home study of the DEKA Arm. Design and methodological procedures used: Differences between groups were examined using chi-square and t-tests. A multivariable logistic regression model predicting completion was generated and odds ratios (OR) for significant variables calculated. Post-hoc analysis was performed to plot the receiver operating characteristics (ROC) curve. RESULTS: Participants who completed were more likely to be prosthesis users at study onset (p = .03), and less likely to have a history of musculoskeletal problems (p = .047). There were no statistically significant differences between groups who completed and those who did not in gender, race, veteran status, age, body mass index (BMI), weight, height, musculoskeletal pain at baseline, satisfaction with current prosthesis, type of prosthesis, or months of prosthesis use. Two variables, prosthesis use and history of musculoskeletal problems were significant at p < .10. The area under the curve (AUC) accuracy index was 0.78. CONCLUSIONS: We considered completion of the home use study a reasonable proxy for participant willingness to adopt the device; and believe that findings can be extrapolated to guide DEKA Arm prescription recommendations. Participants most likely to complete the study were already using a personal prosthesis, and without pre-existing musculoskeletal problems. Implications for rehabilitation Data from the VA Study of the DEKA Arm were analysed to determine which factors were associated with likely successful adoption of the DEKA Arm. Participants most likely to complete the study were those who already using a personal prosthesis, and those without pre-existing chronic or re-occurring musculoskeletal problems. This information may be useful when attempting to identify and target the most appropriate candidates for DEKA Arm prescription.

Use of the DEKA Arm for amputees with brachial plexus injury: A case series.

OBJECTIVE: Patients with upper limb amputation and brachial plexus injuries have high rates of prosthesis rejection. Study purpose is to describe experiences of subjects with transhumeral amputation and brachial plexus injury, who were fit with, and trained to use, a DEKA Arm. METHODS: This was a mixed-methods study utilizing qualitative (e.g. interview, survey) and quantitative data (e.g. self-report and performance measures). Subject 1, a current prosthesis user, had a shoulder arthrodesis. Subject 2, not a prosthesis user, had a subluxed shoulder. Both were trained in laboratory and participated in a trial of home use. Descriptive analyses of processes and outcomes were conducted. RESULTS: Subject 1 was fitted with the transhumeral configuration (HC) DEKA Arm using a compression release stabilized socket. He had 12 hours of prosthetic training and participated in all home study activities. Subject 1 had improved dexterity and prosthetic satisfaction with the DEKA Arm and reported better quality of life (QOL) at the end of participation. Subject 2 was fit with the shoulder configuration (SC) DEKA Arm using a modified X-frame socket. He had 30 hours of training and participated in 3 weeks of home activities. He reported less functional disability at the end of training as compared to baseline, but encountered personal problems and exacerbation of PTSD symptoms and withdrew from home use portion at 3 weeks. Both subjects reported functional benefits from use, and expressed a desire to receive a DEKA Arm in the future. DISCUSSION: This paper reported on two different strategies for prosthetic fitting and their outcomes. The advantages and limitations of each approach were discussed. CONCLUSION: Use of both the HC and SC DEKA Arm for patients with TH amputation and brachial plexus injury was reported. Lessons learned may be instructive to clinicians considering prosthetic choices for future cases.

Self-reported and performance-based outcomes using DEKA Arm.

Mechanical properties of the DEKA Arm and associated engineering innovations are easy to observe. What is less clear is how these advances translate into functional benefits for the user with amputation. Study aims were to (1) quantify outcomes including dexterity, performance of daily activities, and prosthetic skill and spontaneity of users of the DEKA Arm and (2) compare outcomes when using the DEKA Arm with scores using the existing prosthesis. This was a quasi-experimental study. Descriptive analyses examined outcomes by DEKA Arm configuration level. Of the 39 subjects fit with a DEKA Arm, 32 were trained in use and completed end-of-study testing. Data from 26 prosthetic users were used to compare outcomes using existing prostheses with outcomes with the DEKA Arm. Dexterity and activity performance with the DEKA Arm varied by amputation level (p < 0.01). Self-reported function and number of activities performed using the prosthesis were similar across levels. Comparisons with existing prostheses showed the effect on dexterity varied by level. Activity performance and spontaneity of prosthetic use improved for users of the shoulder configuration level, while use of the prosthesis to perform activities and perceived difficulty performing self-selected tasks improved for all levels.

Do users want to receive a DEKA Arm and why? Overall findings from the Veterans Affairs Study to optimize the DEKA Arm.

BACKGROUND: The purposes of this article are (1) to report on the overall desirability of the DEKA Arm by prototype and by level of prosthesis, (2) to report on user-perceived benefits of the DEKA Arm as compared to their current prostheses, and (3) to summarize user concerns about taking the device home. STUDY DESIGN: Qualitative content analysis of data from a multiple case study design. METHODS: This study utilized data from 24 upper-limb amputees fit with a Gen 2 DEKA Arm and 13 fit with a Gen 3 DEKA Arm. Surveys were administered after fitting the DEKA Arm and at the end of training. Subjects recorded audiotaped comments about their experiences. All study sessions were videotaped. RESULTS: In all, 79% of Gen 2 and 85% of Gen 3 users indicated that either they wanted to receive or might want to receive a DEKA Arm. In total, 95% of Gen 2 and 91% of Gen 3 prior prosthesis users reported that they were able to perform new activities that they were unable to perform with their own device. CONCLUSIONS: A large majority of subjects wanted a DEKA Arm, although desirability varied by amputation level. CLINICAL RELEVANCE: The majority of amputees in this study expressed a desire to receive the DEKA Arm, a device which provides multiple powered degrees of freedom and is operated predominantly by foot controls. The majority reported functional advantages of the DEKA Arm over their existing prostheses.

Preferences for rehabilitation services among women with major limb amputations.

PURPOSE: We present five cases of adult females with major limb amputations, their concerns and preferences for services across the life span. DESIGN: A convenience sample of five veteran and nonveteran women aged 19-58 with major limb amputations participating in a regional VA Prosthetics Conference in 2010 took part in a panel interview. FINDINGS: The concerns identified by these women as high priorities included independence and participation in a full range of life activities, limitations in access, patient decision-making and body image concerns, and preferences for selected services. Maximizing function and quality of life for women amputees requires identifying patient preferences for rehabilitation and prosthetic services. Lessons learned could inform development of clinic-based rehabilitation care, prosthetic services, and studies of women with major limb amputations. CONCLUSIONS: As the current conflicts in Iraq and Afghanistan wind down, the number of women veterans seeking rehabilitation and prosthetic services will increase. With this information, rehabilitation and prosthetic service providers and organizations will be uniquely positioned to provide prevention and treatment of amputations for this growing population of women veterans in national care delivery systems and in communities. CLINICAL RELEVANCE: An open-ended facilitated discussion among a panel of women with major limb amputations provided insights for providers and organizations with respect to needs, concerns, and preferences for rehabilitation and prosthetic services.

Patient safety in the rehabilitation of the adult with an amputation.

This article reviews and summarizes the literature on patient safety issues in the rehabilitation of adults with an amputation. Safety issues in the following areas are discussed; the prosthesis, falls, wound care, pain, and treatment of complex patients. Specific recommendations for further research and implementation strategies to prevent injury and improve safety are also provided. Communication between interdisciplinary team members and patient and caregiver education are crucial to executing a safe treatment plan. The multidisciplinary rehabilitation team members should feel comfortable discussing safety issues with patients and be able to recommend preventive approaches to patients as appropriate.

Lessons learned in pilot testing specialty consultations to benefit individuals with lower limb loss.

Telerehabilitation technologies enable the delivery of rehabilitation services from providers to people with disabilities as well as specialty care consultations. This article discusses the barriers experienced when planning and pilot testing a telerehabilitation multi-site specialty consultation for specialists in their medical centers, and the lessons learned. The barriers included integration and participation, coordination across organizational units, and privacy and information security. Lessons learned included the need for collaboration across multiple departments, telerehabilitation equipment back-ups, and anonymous and private communication protocols. Despite delays resulting from coordination at multiple levels of a national organization, we developed a program plan and successfully implemented a pilot test of the southeast region program. Specialty consultation using telerehabilitation delivery methods requires identifying provider preferences for technological features. Lessons learned could inform development of outpatient telerehabilitation for patients with amputations and studies of patients and providers involved in telerehabilitation.