Forearm amputees' views of prosthesis use and sensory feedback.

STUDY DESIGN: Qualitative descriptive. INTRODUCTION: The lack of sensory feedback in today's hand prostheses has been in focus recently but the amputees' experiences need to be further investigated. PURPOSE: To explore forearm amputees' views of prosthesis use and sensory feedback. METHODS: Thirteen unilateral congenital or traumatic forearm amputees were interviewed. The transcribed text was subjected to content analysis. RESULTS: Prostheses both facilitate and limit occupational performance. Appearance is important for identity and blending into society. The feeling of agency regarding the prostheses is present but not that of body ownership. Future expectations concerned improved mobility, cosmetics, and sensory feedback. CONCLUSIONS: This study allows a deeper understanding of the complex relationship between a prosthetic device and the wearer. Today's prostheses allow the wearer to feel agency concerning the artificial limb but the lack of sensory feedback seems to be an important factor still blocking the achievement of body ownership of the prosthesis. LEVEL OF EVIDENCE: Not applicable.

A BIONIC HAND VS. A REPLANTED HAND.

Objective: Evaluation of the hand function affected when replacing a malfunctioning hand by a bionic hand. Design: Case report. Subjects: One individual that wished for a better quality of life after unsatisfying hand function following a replantation. Methods: A quantitative and qualitative evaluation of body functions as well as activity performance and participation before and after a planned amputation and prosthetic fitting is presented. Results: Improvements were seen in the patient-reported outcome measures (PROMs) that were used regarding activity (Disability of the Arm, Shoulder and Hand [DASH] and Canadian Occupational Performance Measure [COPM]), pain (Neuropathic Pain Symptom Inventory [NPSI], Brief Pain Inventory [BPI], Visual Analogue Scale [VAS]), cold intolerance (CISS) and health related quality of life (SF-36), as well as in the standardised grip function test, Southampton Hand Assessment Procedure (SHAP). No referred sensations were seen but the discriminative touch on the forearm was improved. In the qualitative interview, a relief of pain, a lack of cold intolerance, improved appearance, better grip function and overall emotional wellbeing were expressed. Conclusions: The planned amputation and subsequent fitting and usage of a hand prosthesis were satisfying for the individual with positive effects on activity and participation. Clinical relevance: When the hand function after a hand replantation does not reach satisfactory levels, a planned amputation and a prosthetic hand can be the right solution.

The concurrent validity of the Amharic version of Screening of Activity Limitation and Safety Awareness (SALSA) in persons affected by leprosy.

OBJECTIVES: Leprosy is endemic in many countries and results in activity limitations. There is a need for assessment tools to guide professionals in their evaluation and choice of intervention in order to improve conditions for leprosy-affected people. The purpose of our study was to evaluate the concurrent validity of the Amharic version of Screening of Activity Limitation and Safety Awareness (SALSA-am) scale with Amharic version of Disability of the Arm, Shoulder and Hand (DASH-am) questionnaire. DESIGN: Thirty-eight individuals with nerve damage due to leprosy completed the SALSA-am and DASH-am questionnaires. Spearman's rank correlation was used to determine relationships between SALSA and DASH scores. Specificity, sensitivity and accuracy were calculated. RESULTS: There was a good correlation 0.87 (P < 0.001) between SALSA-am and DASH-am scores. Sensitivity, specificity and accuracy were calculated with acceptable results. CONCLUSIONS: SALSA-am is considered a useful questionnaire for determining activity limitations in persons affected by leprosy, and showed good correlation with DASH-am. The concurrent validity was considered good.

The rubber hand illusion evaluated using different stimulation modalities.

Tactile feedback plays a vital role in inducing ownership and improving motor control of prosthetic hands. However, commercially available prosthetic hands typically do not provide tactile feedback and because of that the prosthetic user must rely on visual input to adjust the grip. The classical rubber hand illusion (RHI) where a brush is stroking the rubber hand, and the user's hidden hand synchronously can induce ownership of a rubber hand. In the classic RHI the stimulation is modality-matched, meaning that the stimulus on the real hand matches the stimulus on the rubber hand. The RHI has also been used in previous studies with a prosthetic hand as the "rubber hand," suggesting that a hand prosthesis can be incorporated within the amputee's body scheme. Interestingly, previous studies have shown that stimulation with a mismatched modality, where the rubber hand was brushed, and vibrations were felt on the hidden hand also induced the RHI. The aim of this study was to compare how well mechanotactile, vibrotactile, and electrotactile feedback induced the RHI in able-bodied participants and forearm amputees. 27 participants with intact hands and three transradial amputees took part in a modified RHI experiment. The rubber hand was stroked with a brush, and the participant's hidden hand/residual limb received stimulation with either brush stroking, electricity, pressure, or vibration. The three latter stimulations were modality mismatched with regard to the brushstroke. Participants were tested for ten different combinations (stimulation blocks) where the stimulations were applied on the volar (glabrous skin), and dorsal (hairy skin) sides of the hand. Outcome was assessed using two standard tests (questionnaire and proprioceptive drift). All types of stimulation induced RHI but electrical and vibration stimulation induced a stronger RHI than pressure. After completing more stimulation blocks, the proprioceptive drift test showed that the difference between pre- and post-test was reduced. This indicates that the illusion was drifting toward the rubber hand further into the session.

Outcomes of proximal interphalangeal joint pyrocarbon implants.

PURPOSE: To prospectively register and report the hand function and occupational performance of patients with proximal interphalangeal joint-pyrocarbon arthroplasty, using both objective tests and subjective outcome instruments. METHODS: From 2004 to 2008, 53 joints in 43 patients were reconstructed with a proximal interphalangeal joint-pyrocarbon prosthesis. The patients underwent a rehabilitation program allowing early motion with an extension stop to limit hyperextension. Range of motion, grip strength, and pain (Visual Analog Scale [VAS]) were recorded and the subjective outcome was evaluated using Canadian Occupational Performance Measure (COPM) and Disabilities of the Arm, Shoulder, and Hand score. RESULTS: Seven patients were reoperated on (2 infections, 2 arthrodesis, 2 tenolysis, and 1 hyperextension). Pain (VAS) at rest improved from 3.1 cm preoperatively to 0.4 cm (p < .001) and pain (VAS) at activity from 6.2 to 2.0 cm (p < .001) at the latest follow-up (mean, 24 months; minimum, 12 months [+/- 2 weeks]). Disabilities of the Arm, Shoulder, and Hand score improved from a median of 39 to 29 (p = .026). The COPM subjective measurement of occupational performance, improved from a median of 4.6 preoperatively to 5.9 (p = .013) at the latest follow-up, and the COPM, measurement of satisfaction improved from a median of 3.8 to 5.9 (p = .002). Range of motion and grip strength were unchanged. CONCLUSIONS: All patients reported decreased pain, and although we found no improvement in range of motion and grip strength, one third of patients reported a clinically significant improvement in occupational performance and satisfaction. A total of 13% of the joints required a secondary surgical procedure. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Sensory Feedback in Hand Prostheses: A Prospective Study of Everyday Use.

INTRODUCTION: Sensory feedback in hand prostheses is lacking but wished for. Many amputees experience a phantom hand map on their residual forearm. When the phantom hand map is touched, it is experienced as touch on the amputated hand. A non-invasive sensory feedback system, applicable to existing hand prostheses, can transfer somatotopical sensory information via phantom hand map. The aim was to evaluate how forearm amputees experienced a non-invasive sensory feedback system used in daily life over a 4-week period. METHODS: This longitudinal cohort study included seven forearm amputees. A non-invasive sensory feedback system was used over 4 weeks. For analysis, a mixed method was used, including quantitative tests (ACMC, proprioceptive pointing task, questionnaire) and interviews. A directed content analysis with predefined categories sensory feedback from the prosthesis, agency, body ownership, performance in activity, and suggestions for improvements was applied. RESULTS: The results from interviews showed that sensory feedback was experienced as a feeling of touch which contributed to an experience of completeness. However, the results from the questionnaire showed that the sense of agency and performance remained unchanged or deteriorated. The ability to feel and manipulate small objects was difficult and a stronger feedback was wished for. Phantom pain was alleviated in four out of five patients. CONCLUSION: This is the first time a non-invasive sensory feedback system for hand prostheses was implemented in the home environment. The qualitative and quantitative results diverged. The sensory feedback was experienced as a feeling of touch which contributed to a feeling of completeness, linked to body ownership. The qualitative result was not verified in the quantitative measurements. CLINICAL TRIAL REGISTRATION: Name: Evaluation of a Non-invasive Sensory Feedback System in Hand Prostheses. Date of registration: March 15, 2019. Date the first participant was enrolled: April 1, 2015. ClinicalTrials.gov Identifier: NCT03876405 ORCID ID: https://orcid.org/0000-0002-4140-7478.

Touch on predefined areas on the forearm can be associated with specific fingers: Towards a new principle for sensory feedback in hand prostheses.

OBJECTIVE: Currently available hand prostheses lack sensory feedback. A "phantom hand map", a referred sensation, on the skin of the residual arm is a possible target to provide amputees with non-invasive somatotopically matched sensory feedback. How-ever, not all amputees experience a phantom hand map. The aim of this study was to explore whether touch on predefined areas on the forearm can be associated with specific fingers. DESIGN: A longitudinal cohort study. SUBJECTS: A total of 31 able-bodied individuals. METHODS: A "tactile display" was developed consisting of 5 servo motors, which provided the user with mechanotactile stimulus. Predefined pressure points on the volar aspect of the forearm were stimulated during a 2-week structured training period. RESULTS: Agreement between the stimulated areas and the subjects' ability to discriminate the stimulation was high, with a distinct improvement up to the third training occasion, after which the kappa score stabilized for the rest of the period. CONCLUSION: It is possible to associate touch on intact skin on the forearm with specific fingers after a structured training period, and the effect persisted after 2 weeks. These results may be of importance for the development of non-invasive sensory feedback systems in hand prostheses.

A review of invasive and non-invasive sensory feedback in upper limb prostheses.

INTRODUCTION: The constant challenge to restore sensory feedback in prosthetic hands has provided several research solutions, but virtually none has reached clinical fruition. A prosthetic hand with sensory feedback that closely imitates an intact hand and provides a natural feeling may induce the prosthetic hand to be included in the body image and also reinforces the control of the prosthesis. Areas covered: This review presents non-invasive sensory feedback systems such as mechanotactile, vibrotactile, electrotactile and combinational systems which combine the modalities; multi-haptic feedback. Invasive sensory feedback has been tried less, because of the inherent risk, but it has successfully shown to restore some afferent channels. In this review, invasive methods are also discussed, both extraneural and intraneural electrodes, such as cuff electrodes and transverse intrafascicular multichannel electrodes. The focus of the review is on non-invasive methods of providing sensory feedback to upper-limb amputees. Expert commentary: Invoking embodiment has shown to be of importance for the control of prosthesis and acceptance by the prosthetic wearers. It is a challenge to provide conscious feedback to cover the lost sensibility of a hand, not be overwhelming and confusing for the user, and to integrate technology within the constraint of a wearable prosthesis.

Sensory qualities of the phantom hand map in the residual forearm of amputees.

OBJECTIVE: Most amputees experience referred sensations, known as a phantom hand map, on the residual forearm, where touch on specific areas is perceived as touch on the amputated hand. The aim of this study was to evaluate the sensory qualities of the phantom hand map. METHODS: In 10 traumatic forearm-amputees touch thres-holds and discriminative touch of the phantom hand map were assessed and compared with corresponding areas on the contralateral forearm. The study assessed the localization of touch on the phantom hand map, and how distinct and similar to normal touch the referred feeling was. RESULTS: Similar touch thresholds were seen in the phantom hand map and the control site. Tactile discrimination, requiring both detection of stimulus and interpretation, was significantly better in the phantom hand map. CONCLUSION: This explorative study suggests that the phantom hand map and the superior tactile discrimination seen in the phantom hand map are based on adaptations within the brain. Further studies investigating the neural basis for the phantom hand map are needed.