Peripheral intraneural stimulation can provide tactile information to amputees. However, efforts are still necessary to identify encoding strategy eliciting percepts that are felt as both natural and ...effective for prosthesis control. Here we compared the naturalness and efficacy of different encoding strategies to deliver neural stimulation to trans-radial amputees implanted with intraneural electrodes. Biomimetic frequency modulation was perceived as more natural, while amplitude modulation enabled better performance in tasks requiring fine identification of the applied force. Notably, the optimal combination of naturalness and sensitivity of the tactile feedback can be achieved with “hybrid” encoding strategies based on simultaneous biomimetic frequency and amplitude neuromodulation. These strategies improved the gross manual dexterity of the subjects during functional task while maintaining high levels of manual accuracy. They also improved prosthesis embodiment, reducing abnormal phantom limb perceptions (“telescoping effect”). Hybrid strategies are able to provide highly sensitive and natural percepts and should be preferred.
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•Biomimetic hybrid sensory encodings are perceived as highly natural•Biomimetic hybrid sensory encodings restore rich tactile sensitivity•Biomimetic hybrid sensory encodings improve manual dexterity and accuracy•Biomimetic hybrid sensory encodings enhance prosthesis embodiment
Sensory encoding strategies are used to convey sensory information to upper limb amputees. Valle et al. present strategies based on biomimetic approaches that improve sensation naturalness, tactile sensitivity, manual dexterity, and prosthesis embodiment.
To present population data on standardized measures of dexterity, activity performance, disability, health-related quality of life (HRQoL) and community integration for persons with upper limb ...amputation (ULA), compare outcomes to normative values, and examine differences by prosthesis type and laterality (unilateral vs. bilateral amputation).
Multi-site, cross-sectional design, with in-person evaluations, functional performance, and self-report measures. Descriptive and comparative analyses were performed by amputation level and prosthesis type, data were compared for unilateral and bilateral amputation.
One hundred and twenty-seven individuals participated; mean age 57 years, 59% percent body-powered prostheses users. All measures of dexterity differed (p < 0.05) by amputation level and by laterality. All measures of activity differed by amputation level with the best scores in transradial (TR) amputation groups. Comparisons of body-powered users with TR amputation found that dexterity was better for those with bilateral compared to unilateral amputation.
Dexterity is markedly impaired in persons with ULA. Individuals with more proximal ULA levels are most impacted. HRQoL and community participation are less impacted and more equivalent to unimpaired persons. Further research is needed to examine differences by terminal device type and determine how best to match persons with ULA to the optimal prosthesis type and componentry, based on individual characteristics.
Implications for Rehabilitation
This study provides population-based, comparative data on dexterity, activity performance, disability, quality of life, and independence in upper limb prosthesis users.
The study provides preliminary analyses comparing the effectiveness of body-powered devices, myoelectric devices with single degree of freedom and multi-degree of freedom terminal devices.
The data presented in this study can be used to benchmark outcomes in patients who are upper limb prosthesis users.
The data will also be useful to inform comparative evaluations of existing and emerging prosthetic technology.
To identify the most important health-related quality of life (HRQOL) domains and patient-reported outcomes after upper extremity transplantation (UET) in individuals with upper extremity amputation.
...Verbatim audio-recordings of individual interviews and focus groups were analyzed using qualitative, grounded theory-based methods to identify important domains of HRQOL and provide guidance for outcomes measurement after UET.
Individual interviews were conducted by phone. Focus groups were conducted at 5 upper extremity vascularized composite allotransplantation (VCA) centers in the US and at an international conference of VCA experts.
Individual phone interviews were conducted with 5 individuals with lived experience of UET. Thirteen focus groups were conducted with a total of 59 clinical professionals involved in UET.
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Twenty-eight key HRQOL domains were identified, including physical functioning and medical complications, positive and negative emotional functioning, and social participation, relations, and independence. We identified key constructs for use in evaluation of the potentially substantial physical, medical, social, and emotional effects of UET.
This study provides an overview of the most important issues affecting HRQOL after UET, including several topics that are unique to individuals with UET. This information will be used to establish systematic, comprehensive, and longitudinal measurement of post-UET HRQOL outcomes.
To develop a self-report measure of activity performance for upper limb prosthesis users that quantifies outcomes by level of amputation and prosthesis type.
Telephone survey of 423 adults with major ...upper limb amputation (ULA) who used a prosthesis. Item generation, cognitive, and pilot testing were followed by field testing. Items were categorized as one- or two-handed. Factor and Rasch analyses evaluated unidimensionality, monotonicity, item fit, differential item functioning (DIF), and reliability. Test-retest reliability was evaluated with intraclass correlation coefficients (ICCs). Known group validity was assessed with ANOVAs.
Respondents with unilateral ULA utilized prosthesis for 24% of unilateral and 38% of bilateral tasks. Those with bilateral ULA utilized prostheses for 64% of unilateral and 46% of bilateral tasks. Factor analyses identified a One-handed Task factor (CFI = 0.963, TLI = 0.950, and RMSEA = 0.064) and a Two-Handed Task factor (CFI = 0.958, TLI = 0.953, and RMSEA = 0.053). Response categories were collapsed to address monotonicity. After DIF adjustment, person reliability was 0.49 and 0.82 for One-handed and Two-handed Task scales, respectively, and ICCs were 0.88 and 0.91. Both scales differed by amputation level (p < 0.001).
The Upper Extremity Functional Scale for Prosthesis Users (UEFS-P) measure of upper limb function of prosthesis users has promising psychometric properties.
Implications for rehabilitation
Measurement of upper limb function in persons with amputation is challenging, given currently available measures which do not explicitly grade activity performance with a prosthesis.
The Upper Extremity Functional Scale for Prosthesis Users (UEFS-P) builds upon the original Orthotics and Prosthetics User Survey (OPUS) UEFS Scale with modified instructions, a revised item set, response categories and scoring algorithm.
The UEFS-P consists of two unidimensional scales, the One-handed Tasks scale and the Two-handed Tasks scale.
The UEFS-P scales have clear advantages over existing self-report measures of upper limb function that ask about difficulty with performing functional activities without accounting for prosthesis use, and do not differentiate persons who use and do not use a prosthesis.
The replacement of a missing hand by a prosthesis is one of the most fascinating challenges in rehabilitation engineering. State of art prostheses are curtailed by the physical features of the hand, ...like poor functionality and excessive weight. Here we present a new multi-grasp hand aimed at overcoming such limitations. The SSSA-MyHand builds around a novel transmission mechanism that implements a semi-independent actuation of the abduction/adduction of the thumb and of the flexion/extension of the index, by means of a single actuator. Thus, with only three electric motors the hand is capable to perform most of the grasps and gestures useful in activities of daily living, akin commercial prostheses with up to six actuators, albeit it is as lightweight as conventional 1-Degrees of Freedom prostheses. The hand integrates position and force sensors and an embedded controller that implements automatic grasps and allows inter-operability with different human-machine interfaces. We present the requirements, the design rationale of the first prototype and the evaluation of its performance. The weight (478 g), force (31 N maximum force at the thumb fingertip) and speed of the hand (closing time: <;370 ms), make this new design an interesting alternative to clinically available multi-grasp prostheses.
People with upper extremity (UE) amputations report receiving insufficient information about treatment options. Furthermore, patients commonly report not knowing what questions to ask providers. A ...question prompt sheet (QPS), or list of questions, can support patient-centered care by empowering patients to ask questions important to them, promoting patient-provider communication, and increasing patient knowledge. This study assessed information needs among people with UE amputations about UE vascularized composite allotransplantation (VCA) and developed a UE VCA-QPS.
This multi-site, cross-sectional, mixed-methods study involved in-depth and semi-structured interviews with people with UE amputations to assess information needs and develop a UE VCA-QPS. Qualitative data were analyzed by thematic analysis; quantitative data were analyzed by descriptive statistics. The initial UE VCA-QPS included 130 items across 18 topics.
Eighty-nine people with UE amputations participated. Most were male (73%), had a mean age of 46 years, and had a unilateral (84%) and below-elbow amputation (56%). Participants desired information about UE VCA eligibility, evaluation process, surgery, risks, rehabilitation, and functional outcomes. After refinement, the final UE VCA-QPS included 35 items, across 9 topics. All items were written at a ≤ 6th grade reading level. Most semi-structured interview participants (86%) reported being 'completely' or 'very' likely to use a UE VCA-QPS.
People with UE amputations have extensive information needs about UE VCA. The UE VCA-QPS aims to address patients' information needs and foster patient-centered care. Future research should assess whether the UE VCA-QPS facilitates patient-provider discussion and informed decision-making for UE VCA.
Restoring somatosensory feedback to people with limb amputations is crucial to improve prosthetic control. Multiple studies have demonstrated that peripheral nerve stimulation and targeted ...reinnervation can provide somatotopically relevant sensory feedback. While effective, the surgical procedures required for these techniques remain a major barrier to translatability. Here, we demonstrate in four people with upper-limb amputation that epidural spinal cord stimulation (SCS), a common clinical technique to treat pain, evoked somatosensory percepts that were perceived as emanating from the missing arm and hand. Over up to 29 days, stimulation evoked sensory percepts in consistent locations in the missing hand regardless of time since amputation or level of amputation. Evoked sensations were occasionally described as naturalistic (e.g. touch or pressure), but were often paresthesias. Increasing stimulus amplitude increased the perceived intensity linearly, without increasing area of the sensations. These results demonstrate the potential of SCS as a tool to restore somatosensation after amputations.
•Amputation causes the reorganization of sensory-motor areas and reshapes intra- and inter-hemispheric connectivity.•The “orphan“ cortical areas maintain hushed connections with the corresponding ...peripheral areas.•Amputees show changes in corticospinal excitability depending on amputation level.
To evaluate cortical circuits and excitability of the motor cortex in the hemisphere contralateral to the affected (AH) and to the unaffected arm (UH), in upper limb amputees.
Motor evoked potentials (MEP) were recorded in 17 subjects who had upper limb amputation: 11 trans-radial (TR) and 6 trans-humeral (TH). Motor thresholds (MT), short interval intracortical inhibition (SICI), and interhemispheric inhibition (IHI) in the available arm muscles of the stump were evaluated.
There was no significant difference in MT between hemispheres. SICI was preserved in TR but not in TH group. Additionally, in the TR group, the MEP amplitudes in AH were higher than in UH. A significant IHI was observed in the whole sample but not in each hemisphere or patient group.
In our population of TR amputees, we found increased corticospinal excitability in the AH with preserved intracortical inhibition. This finding was not observed in the TH population.
Understanding the changes in intracortical excitability in amputees may enhance knowledge of the functional reorganization of the brain in the post-amputation phase, bringing useful information for prosthetic rehabilitation.
A flail limb can be the result of a traumatic complete brachial plexus lesion. Some patients prefer retaining the flail limb, however some patients feel that a flail limb negatively affects daily ...life. In these circumstances an elective amputation is sometimes elected, however long-term follow-up, with respect to satisfaction and function is unknown. The aim of this study is to evaluate the long-term outcome of this rare and life changing operation.
8 patients with a transhumeral amputation performed in 2 specialized medical centers were included. Postoperatively, the functional- and psychological outcome and the quality of life were evaluated with standardized patient reported outcome measures (PROMs; DASH, SIP-68, EQ-5D-5L and HADS).
After a median of 9.4 (range 7.5 – 12.8) years follow-up, 7 patients (88%) stated that they would undergo the operation again and were satisfied with the results. At latest follow-up the median DASH score was 37.3 (range 8.3-61.7), the median SIP-68 score was 6.5 (range 0-43) and the median HADS score was 3.0 (range 0-14) for anxiety and 3.0 (range 1-19) for depression. In the EQ-5D-5L patients had most difficulties in self-care, usual activities and pain/discomfort. The median overall health status was 69 (range 20-95).
With the right indication a transhumeral amputation is a reasonable option for traumatic complete brachial plexus lesion with satisfying long-term results.
IV, multicenter case series.
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