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1.
Sensors (Basel) ; 21(19)2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34640956

RESUMO

Stumbling during gait is commonly encountered in patients who suffer from mild to serious walking problems, e.g., after stroke, in osteoarthritis, or amputees using a lower leg prosthesis. Instead of self-reporting, an objective assessment of the number of stumbles in daily life would inform clinicians more accurately and enable the evaluation of treatments that aim to achieve a safer walking pattern. An easy-to-use wearable might fulfill this need. The goal of the present study was to investigate whether a single inertial measurement unit (IMU) placed at the shank and machine learning algorithms could be used to detect and classify stumbling events in a dataset comprising of a wide variety of daily movements. Ten healthy test subjects were deliberately tripped by an unexpected and unseen obstacle while walking on a treadmill. The subjects stumbled a total of 276 times, both using an elevating recovery strategy and a lowering recovery strategy. Subjects also performed multiple Activities of Daily Living. During data processing, an event-defined window segmentation technique was used to trace high peaks in acceleration that could potentially be stumbles. In the reduced dataset, time windows were labelled with the aid of video annotation. Subsequently, discriminative features were extracted and fed to train seven different types of machine learning algorithms. Trained machine learning algorithms were validated using leave-one-subject-out cross-validation. Support Vector Machine (SVM) algorithms were most successful, and could detect and classify stumbles with 100% sensitivity, 100% specificity, and 96.7% accuracy in the independent testing dataset. The SVM algorithms were implemented in a user-friendly, freely available, stumble detection app named Stumblemeter. This work shows that stumble detection and classification based on SVM is accurate and ready to apply in clinical practice.


Assuntos
Atividades Cotidianas , Membros Artificiais , Marcha , Humanos , Máquina de Vetores de Suporte , Caminhada
2.
Sensors (Basel) ; 21(18)2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34577219

RESUMO

(1) Background: Semi-active prosthetic feet can provide adaptation in different circumstances, enabling greater function with less weight and complexity than fully powered prostheses. However, determining how to control semi-active devices is still a challenge. The dynamic mean ankle moment arm (DMAMA) provides a suitable biomechanical metric, as its simplicity matches that of a semi-active device. However, it is unknown how stiffness and locomotion modes affect DMAMA, which is necessary to create closed-loop controllers for semi-active devices. In this work, we develop a method to use only a prosthesis-embedded load sensor to measure DMAMA and classify locomotion modes, with the goal of achieving mode-dependent, closed-loop control of DMAMA using a variable-stiffness prosthesis. We study how stiffness and ground incline affect the DMAMA, and we establish the feasibility of classifying locomotion modes based exclusively on the load sensor. (2) Methods: Human subjects walked on level ground, ramps, and stairs while wearing a variable-stiffness prosthesis in low-, medium-, and high-stiffness settings. We computed DMAMA from sagittal load sensor data and prosthesis geometric measurements. We used linear mixed-effects models to determine subject-independent and subject-dependent sensitivity of DMAMA to incline and stiffness. We also used a machine learning model to classify locomotion modes using only the load sensor. (3) Results: We found a positive linear sensitivity of DMAMA to stiffness on ramps and level ground. Additionally, we found a positive linear sensitivity of DMAMA to ground slope in the low- and medium-stiffness conditions and a negative interaction effect between slope and stiffness. Considerable variability suggests that applications of DMAMA as a control input should look at the running average over several strides. To examine the efficacy of real-time DMAMA-based control systems, we used a machine learning model to classify locomotion modes using only the load sensor. The classifier achieved over 95% accuracy. (4) Conclusions: Based on these findings, DMAMA has potential for use as a closed-loop control input to adapt semi-active prostheses to different locomotion modes.


Assuntos
Amputados , Membros Artificiais , Tornozelo , Fenômenos Biomecânicos , Marcha , Humanos , Desenho de Prótese , Caminhada
3.
Sensors (Basel) ; 21(18)2021 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-34577443

RESUMO

Myoelectric prosthesis has become an important aid to disabled people. Although it can help people to recover to a nearly normal life, whether they can adapt to severe working conditions is a subject that is yet to be studied. Generally speaking, the working environment is dominated by vibration. This paper takes the gripping action as its research object, and focuses on the identification of grasping intentions under different vibration frequencies in different working conditions. In this way, the possibility of the disabled people who wear myoelectric prosthesis to work in various vibration environment is studied. In this paper, an experimental test platform capable of simulating 0-50 Hz vibration was established, and the Surface Electromyography (sEMG) signals of the human arm in the open and grasping states were obtained through the MP160 physiological record analysis system. Considering the reliability of human intention recognition and the rapidity of algorithm processing, six different time-domain features and the Linear Discriminant Analysis (LDA) classifier were selected as the sEMG signal feature extraction and recognition algorithms in this paper. When two kinds of features, Zero Crossing (ZC) and Root Mean Square (RMS), were used as input, the accuracy of LDA algorithm can reach 96.9%. When three features, RMS, Minimum Value (MIN), and Variance (VAR), were used as inputs, the accuracy of the LDA algorithm can reach 98.0%. When the six features were used as inputs, the accuracy of the LDA algorithm reached 98.4%. In the analysis of different vibration frequencies, it was found that when the vibration frequency reached 20 Hz, the average accuracy of the LDA algorithm in recognizing actions was low, while at 0 Hz, 40 Hz and 50 Hz, the average accuracy was relatively high. This is of great significance in guiding disabled people to work in a vibration environment in the future.


Assuntos
Membros Artificiais , Vibração , Algoritmos , Análise Discriminante , Eletromiografia , Humanos , Reconhecimento Automatizado de Padrão , Reprodutibilidade dos Testes
4.
J Neural Eng ; 18(5)2021 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-34479219

RESUMO

Objective.Supplemental sensory feedback for myoelectric prostheses can provide both psychosocial and functional benefits during prosthesis control. However, the impact of feedback depends on multiple factors and there is insufficient understanding about the fundamental role of such feedback in prosthesis use. The framework of human motor control enables us to systematically investigate the user-prosthesis control loop. In this study, we explore how different task objectives such as speed and accuracy shape the control policy developed by participants in a prosthesis force-matching task.Approach.Participants were randomly assigned to two groups that both used identical electromyography control interface and prosthesis force feedback, through vibrotactile stimulation, to perform a prosthesis force-matching task. However, the groups received different task objectives specifying speed and accuracy demands. We then investigated the control policies developed by the participants. To this end, we not only evaluated how successful or fast participants were but also analyzed the behavioral strategies adopted by the participants to obtain such performance gains.Main results.First, we observed that participants successfully integrated supplemental prosthesis force feedback to develop both feedforward and feedback control policies, as demanded by the task objectives. We then observed that participants who first developed a (slow) feedback policy were quickly able to adapt their policy to more stringent speed demands, by switching to a combined feedforward-feedback control strategy. However, the participants who first developed a (fast) feedforward policy were not able to change their control policy and adjust to greater accuracy demands.Significance.Overall, the results signify how the framework of human motor control can be applied to study the role of feedback in user-prosthesis interaction. The results also reveal the utility of training prosthesis users to integrate supplemental feedback into their state estimation by designing training protocols that encourage the development of combined feedforward and feedback policy.


Assuntos
Membros Artificiais , Eletromiografia , Retroalimentação Sensorial , Força da Mão , Humanos , Políticas , Desenho de Prótese
5.
BMC Musculoskelet Disord ; 22(1): 769, 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34503484

RESUMO

BACKGROUND: Obesity is common in persons with a lower limb amputation, an amputation can also lead to further weight gain. Data regarding the prevalence of obesity in the Dutch population with a lower limb amputation are lacking. Furthermore, the impact of obesity on skin problems of the residual limb and the need of prosthetic repairs is unknown. The aim of this study was to determine the prevalence of obesity in Dutch persons with a lower limb amputation and to investigate the relationship between body weight, body mass index and skin problems of the residual limb and the frequency of prosthetic repairs. METHODS: A survey was performed among adults with a unilateral lower limb amputation due to any cause, and who are user of a prosthesis. The survey consisted of measurement of the subjects' body height and weight, a questionnaire which assessed self-reported skin problems in the previous month and factors potentially associated with these skin problems, and assessment of the frequency of visits to the orthopedic workshop. RESULTS: In total, 413 persons were enrolled. Of them, 39% (95 % confidence interval 35;44) were overweight and 28% (95% confidence interval 24;33) were obese. A total of 77% (95% confidence interval 73;81) reported one or more skin problems in the past month. Body weight and body mass index were neither associated with the presence of skin problems in general nor with the number of prosthetic repairs. Persons with severe skin problems had a slightly lower body mass index (26.6 kg/m2 vs. 28.0 kg/m2, p = 0.012). Persons with skin problems were younger than those without (difference in means 6.0 years (95% confidence interval 3.0;8.9)). CONCLUSIONS: Our findings show that obesity is common in the Dutch ambulant population with a lower limb amputation, with a prevalence being higher than in the general Dutch adult population. However, its negative impact on the presence of skin problems and the frequency of prosthetic repairs may be limited.


Assuntos
Amputação , Membros Artificiais , Índice de Massa Corporal , Pele/patologia , Adulto , Humanos , Extremidade Inferior/cirurgia , Países Baixos , Implantação de Prótese
6.
J Bodyw Mov Ther ; 27: 634-639, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34391299

RESUMO

INTRODUCTION: Lower limb amputation impairs postural performance that could be characterized by biomechanical parameters. This study is to investigate postural performance of persons with transfemoral and transtibial amputation compared to controls without amputation. METHODS: Eight transtibial, nine transfemoral and twelve able-bodied males participated in this study. Lower limb joints, pelvis and trunk angles were obtained from an optoelectronic motion analysis system to evaluate body posture parameters. The mean, range and speed of the center of pressure (CoP) in both antero-posterior and medio-lateral axes as well as the ellipse area covered by 90% of CoP and free moment were calculated using a single force-plate. RESULTS AND DISCUSSION: Differences in body posture were only noted between the non-amputee and the transtibial groups. Transtibial amputees leaned more forwardly their trunk by 3.5° compared to able-bodied (p = 0.028). The mean CoP position in transfemoral amputees was closer to the non-amputated side than transtibial amputees (p = 0.034) and as compared to the dominant side in non-amputees (p = 0.042). Factor analysis revealed three postural performance modalities. Non-amputees postural performance was characterized solely by body posture parameters. Transfemoral amputees exclusively favored a modality associated with standing balance parameters, whereas transtibial amputees exhibited a mixed modality comprising a combination of postural and balance parameters. CONCLUSION: These findings support that the level of amputation is characterized by postural performance modalities different from non-amputees. Clinicians could apply this knowledge as part of their routine rehabilitation program to enhance postural and standing balance assessments in unilateral transfemoral and transtibial amputees.


Assuntos
Amputados , Membros Artificiais , Amputação , Fenômenos Biomecânicos , Humanos , Masculino , Equilíbrio Postural , Postura
7.
Sensors (Basel) ; 21(16)2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34451073

RESUMO

Gait analysis has many applications, and specifically can improve the control of prosthesis, exoskeletons, or Functional Electrical Stimulation systems. The use of canes is common to complement the assistance in these cases, and the synergy between upper and lower limbs can be exploited to obtain information about the gait. This is interesting especially in the case of unilateral assistance, for instance in the case of one side lower limb exoskeletons. If the cane is instrumented, it can hold sensors that otherwise should be attached to the body of the impaired user. This can ease the use of the assistive system in daily life as well as its acceptance. Moreover, Force Sensing Resistors (FSRs) are common in gait phase detection systems, and force sensors are also common in user intention detection. Therefore, a cane that incorporates FSRs on the handle can take advantage from the direct interface with the human and provide valuable information to implement real-time control. This is done in this paper, and the results confirm that many events are detected from variables derived from the readings of the FSRs that provide rich information about gait. However, a large inter-subject variability points to the need of tailored control systems.


Assuntos
Membros Artificiais , Exoesqueleto Energizado , Bengala , Marcha , Humanos , Extremidade Inferior
8.
Sensors (Basel) ; 21(16)2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34451119

RESUMO

Pattern recognition algorithms have been widely used to map surface electromyographic signals to target movements as a source for prosthetic control. However, most investigations have been conducted offline by performing the analysis on pre-recorded datasets. While real-time data analysis (i.e., classification when new data becomes available, with limits on latency under 200-300 milliseconds) plays an important role in the control of prosthetics, less knowledge has been gained with respect to real-time performance. Recent literature has underscored the differences between offline classification accuracy, the most common performance metric, and the usability of upper limb prostheses. Therefore, a comparative offline and real-time performance analysis between common algorithms had yet to be performed. In this study, we investigated the offline and real-time performance of nine different classification algorithms, decoding ten individual hand and wrist movements. Surface myoelectric signals were recorded from fifteen able-bodied subjects while performing the ten movements. The offline decoding demonstrated that linear discriminant analysis (LDA) and maximum likelihood estimation (MLE) significantly (p < 0.05) outperformed other classifiers, with an average classification accuracy of above 97%. On the other hand, the real-time investigation revealed that, in addition to the LDA and MLE, multilayer perceptron also outperformed the other algorithms and achieved a classification accuracy and completion rate of above 68% and 69%, respectively.


Assuntos
Membros Artificiais , Movimento , Algoritmos , Eletromiografia , Mãos , Humanos , Articulação do Punho
9.
BMC Musculoskelet Disord ; 22(1): 721, 2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34425821

RESUMO

BACKGROUND: The aim of this study was to compare the relative performance of total knee replacement constructs and discern if there is variability in performance in currently commonly used prostheses in the New Zealand Joint Registry (NZJR) using a noninferiority analysis. METHODS: All patients who underwent a primary total knee replacement (TKR) registered in the NZJR between 1st January 1999 to June 2020 were identified. Using a noninferiority analysis, the performance of total knee replacement prostheses were compared with the best performing contemporary construct. Construct all-cause revision rate was estimated using the 1-Kaplan Meier survival function method to estimate net failure. The difference in all-cause revision rates between the contemporary benchmark and all other constructs was tested. RESULTS: In total 110 183 TKR were recorded and 25 constructs (102 717 procedures) had > 500 procedures at risk at 3 years post-primary of which 5 were inferior by at least 20 % relative risk of which, one was inferior by at least 100 % relative risk. 14 constructs were identified with > 500 procedures at risk at 10 years with 5 inferior by at least 20 %, of which 2 were inferior by > 100 % relative risk. CONCLUSIONS: We discerned that there is great variability in construct performance and at all time points, greater than 25 % of constructs are inferior to the best performing construct by at least 20 %. These results can help inform patients, clinicians and health care funders when considering TKR surgery.


Assuntos
Artroplastia do Joelho , Membros Artificiais , Artroplastia do Joelho/efeitos adversos , Benchmarking , Humanos , Nova Zelândia/epidemiologia , Falha de Prótese , Sistema de Registros , Reoperação
10.
Sensors (Basel) ; 21(15)2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34372253

RESUMO

Sensor systems to measure pressure at the stump-socket interface of transfemoral amputees are receiving increasing attention as they allow monitoring to evaluate patient comfort and socket fit. However, transfemoral amputees have many unique characteristics, and it is unclear whether existing research on sensor systems take these sufficiently into account or if it is conducted in ways likely to lead to substantial breakthroughs. This investigation addresses these concerns through a scoping review to profile research regarding sensors in transfemoral sockets with the aim of advancing and improving prosthetic socket design, comfort and fit for transfemoral amputees. Publications found from searching four scientific databases were screened, and 17 papers were found relating to the aim of this review. After quality assessment, 12 articles were finally selected for analysis. Three main contributions are provided: a de facto methodology for experimental studies on the implications of intra-socket pressure sensor use for transfemoral amputees; the suggestion that associated sensor design breakthroughs would be more likely if pressure sensors were developed in close combination with other types of sensors and in closer cooperation with those in possession of an in-depth domain knowledge in prosthetics; and that this research would be facilitated by increased interdisciplinary cooperation and open research data generation.


Assuntos
Amputados , Membros Artificiais , Cotos de Amputação , Humanos , Desenho de Prótese , Caminhada
11.
Sensors (Basel) ; 21(15)2021 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-34372482

RESUMO

Commercial myoelectric prostheses are costly to purchase and maintain, making their provision challenging for developing countries. Recent research indicates that embroidered EMG electrodes may provide a more affordable alternative to the sensors used in current prostheses. This pilot study investigates the usability of such electrodes for myoelectric control by comparing online and offline performance against conventional gel electrodes. Offline performance is evaluated through the classification of nine different hand and wrist gestures. Online performance is assessed with a crossover two-degree-of-freedom real-time experiment using Fitts' Law. Two performance metrics (Throughput and Completion Rate) are used to quantify usability. The mean classification accuracy of the nine gestures is approximately 98% for subject-specific models trained on both gel and embroidered electrode offline data from individual subjects, and 97% and 96% for general models trained on gel and embroidered offline data, respectively, from all subjects. Throughput (0.3 bits/s) and completion rate (95-97%) are similar in the online test. Results indicate that embroidered electrodes can achieve similar performance to gel electrodes paving the way for low-cost myoelectric prostheses.


Assuntos
Membros Artificiais , Eletrodos , Eletromiografia , Mãos , Humanos , Projetos Piloto
13.
Rev Assoc Med Bras (1992) ; 67(2): 277-281, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34406253

RESUMO

OBJECTIVE: Few physical exercise programs for children with limb loss have been described in detail recently. We provided information regarding the characteristics and effectiveness of an alternative rehabilitation exercise developed for children with lower-limb amputation. METHODS: An 8-year-old boy with a below-knee amputation and a 9-year-old bilateral amputee girl performed an exercise program of one 2-h session per week for 20 weeks, aimed at developing muscular strength and coordination. Walking ability and walking speed were assessed by using the L-test of functional mobility and 10-m walk test, respectively. Mechanical and neuromuscular muscle function was assessed by using tensiomyography. RESULTS: In case 1, a decrement of 9.5% and 10.5% was found in the L-test (42 s vs. 38 s) and in the 10-m test (19 s vs. 17 s) scores, respectively. In case 2, walking ability remained unchanged (L-test score: 38 s), while a 5.2% reduction in walking speed was observed (10-m test score: 19 s vs. 18 s). No relevant changes were observed in the muscular tone in both cases. CONCLUSIONS: Practitioners should be aware that, contrary to what could be expected, a multidisciplinary training program held once per week for 5 months had a minimal impact on the gait pattern and neuromuscular function of two children with lower-limb amputation.


Assuntos
Amputados , Membros Artificiais , Amputação , Criança , Exercício Físico , Terapia por Exercício , Feminino , Humanos , Masculino , Caminhada
14.
J Neural Eng ; 18(5)2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34416740

RESUMO

Objective.The nervous system subconsciously estimates the state of the body as a weighted average of the information from various sensory sources, where the weights reflect the perceived reliability of each source. Loss of motor functions can be partially compensated using assistive systems (e.g. prostheses), which may also restore somatosensory feedback through tactile stimulation. Whether such artificial feedback is integrated in the neural state estimation process is not known.Approach.In this study, able-bodied subjects performed a grasp force matching task with supplementary non-invasive electrotactile stimulation with a frequency proportional to grasp force magnitude. Before the task, a brief training session taught the subjects to associate the sensation of electrotactile stimulation with the generated grasp force. In some trials, the force-frequency mapping was biased to introduce an unnoticeable mismatch between natural and electrotactile force feedback, thereby provoking the subject to subconsciously estimate the force as a compromise between the two sources of information.Main results.The outcome of this compromise revealed the weights assigned to each feedback type. The grasp forces were significantly affected by the biased mappings, as indicated by the average estimated relative weights (electrotactile: 0.69 ± 0.29; natural: 0.31 ± 0.29). Across subjects, this weight was correlatedr2=0.75) with the improvement in force matching precision when adding the unbiased electrotactile feedback to the natural force feedback, as predicted by maximum likelihood estimation. This shows that even after minimal training the nervous system adopts electrotactile stimulation as a highly reliable source of information that can improve the precision in the estimation of the grip force.Significance.This result has important implications for the restoration of sensory feedback in upper limb prostheses as it indicates that even non-invasive stimulation can be integrated naturally (i.e. subconsciously and effectively) in the motor controlloop.


Assuntos
Membros Artificiais , Força da Mão , Retroalimentação , Retroalimentação Sensorial , Humanos , Reprodutibilidade dos Testes , Tato
15.
Int J Rehabil Res ; 44(3): 193-199, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34356037

RESUMO

Patient's satisfaction with device is an important clinical outcome in prosthetics and orthotics. The Client Satisfaction with Device (CSD) - one of the five modules of the Orthotics and Prosthetics Users' Survey (OPUS) - has been defined as the only outcome measure specifically developed to measure user satisfaction with a prosthesis or an orthosis. The aim of this study was to provide a comprehensive review of the psychometric properties of the CSD, summarizing the present evidence on this measure, and verifying if the scoring system is consistent in the literature. A systematic literature search was conducted utilizing PRISMA guidelines. Articles were searched in PubMed and Scopus databases using search terms relating to the psychometric properties of the CSD. Thirteen articles assessing the psychometric properties of the CSD met the inclusion criteria for this review. The CSD has been translated and validated in several languages. However, these versions are not consistent across the studies since they include different number of items, with different number of response options, and scoring systems. The CSD - where used in its eight-item version, rated with a four-point rating scale - can be judged as a tool with acceptable psychometric properties for assessing satisfaction with devices in prosthesis and orthosis users. This CSD version seems the best one for optimizing coverage and psychometric quality with the fewest number of items. Further studies are warranted to assess the degree of suitability of this scale in specific populations of users of prostheses or orthoses and to analyze its psychometric properties in further cultural contexts.


Assuntos
Membros Artificiais , Satisfação do Paciente , Humanos , Satisfação Pessoal , Psicometria , Reprodutibilidade dos Testes , Inquéritos e Questionários
16.
J Med Life ; 14(3): 383-389, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34377205

RESUMO

Prosthetic rehabilitation of a partial or total maxillectomy with an obturator is the most acceptable treatment option. The hollowing of the obturator prosthesis is beneficial as it reduces the stresses over the underlying and surrounding tissues. A simple technique of fabricating a hollow bulb obturator has been discussed in this article. At the step of the packing of a denture, the hollow wax pattern of the defect area is formed with modeling wax. This hollow wax pattern is filled with water and is allowed to freeze to form an ice block. This ice block is removed from the wax pattern and is interposed between two layers for heat-cured acrylic resin and is then cured. After processing the denture, the water is retrieved by making a small hole in denture base, which is packed after hollowing with a cold cure acrylic resin. A lightweight prosthesis with a uniform thickness was achieved with a readily available and easily retrievable material, i.e., ice.


Assuntos
Membros Artificiais , Obturadores Palatinos , Humanos , Implantação de Prótese
17.
J Biomech ; 125: 110610, 2021 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-34252823

RESUMO

In prosthetic walking mediolateral balance is compromised due to the lack of active ankle control, by moments of force, in the prosthetic limb. Active control is reduced to the hip strategy, and passive mechanical stability depends on the curvature of the prosthetic foot under load. Mediolateral roll-over curvatures of prosthetic feet are largely unknown. In this study we determined the mediolateral roll-over characteristics of various prosthetic feet and foot-shoe combinations. Characteristics were determined by means of an inverted pendulum-like apparatus. The relationship between the centre of pressure (CoP) and the shank angle was measured and converted to roll-over shape and effective radius of curvature. Further, hysteresis (i.e., lagging in CoP displacement due to material compliance or slip) at vertical shank angle was determined from the hysteresis curve. Passive mechanical stability varied widely, though all measured foot-shoe combinations were relatively compliant. Mediolateral motion of the CoP ranged between 4 mm and 40 mm, thereby remaining well within each foot's physical width. Derived roll-over radii of curvature are also small, with an average of 102 mm. Hysteresis ranges between 20% and 115% of total CoP displacement and becomes more pronounced when adding a shoe. This may be due to slipping of the foot core in its cosmetic cover, or the foot in the shoe. Slip may be disadvantageous for balance control by limiting mediolateral travel of the CoP. It may therefore be clinically relevant to eliminate mediolateral slip in prosthetic foot design.


Assuntos
Membros Artificiais , Fenômenos Biomecânicos , , Marcha , Desenho de Prótese , Sapatos , Caminhada
18.
J Biomech ; 125: 110599, 2021 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-34265657

RESUMO

Amputation of a major limb, and the subsequent return to movement with a prosthesis, requires the development of compensatory strategies to account for the loss. Such strategies, over time, lead to regional muscle atrophy and hypertrophy through chronic under or overuse of muscles compared to uninjured individuals. The aim of this study was to quantify the lower limb muscle parameters of persons with transtibial and transfemoral amputations using high resolution MRI to ascertain muscle volume and to determine regression equations for predicting muscle volume using femur- and tibia-length, pelvic-width, height, and mass. Twelve persons with limb loss participated in this study and their data were compared to six matched control subjects. Subjects with unilateral transtibial amputation showed whole-limb muscle volume loss in the residual-limb, whereas minor volume changes in the intact limb were found, providing evidence for a compensation strategy that is dominated by the intact-limb. Subjects with bilateral-transfemoral amputations showed significant muscle volume increases in the short adductor muscles with an insertion not affected by the amputation, the hip flexors, and the gluteus medius, and significant volume decreases in the longer adductor muscles, rectus femoris, and hamstrings. This study presents a benchmark measure of muscle volume discrepancies in persons with limb-loss, and can be used to understand the compensation strategies of persons with limb-loss and the impact on muscle volume, thus enabling the development of optimised intervention protocols, conditioning therapies, surgical techniques, and prosthetic devices that promote and enhance functional capability within the population of persons with limb loss.


Assuntos
Amputados , Membros Artificiais , Amputação , Humanos , Extremidade Inferior , Músculo Esquelético/diagnóstico por imagem
19.
J Neural Eng ; 18(4)2021 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-34229307

RESUMO

Objective.Advanced robotic lower limb prostheses are mainly controlled autonomously. Although the existing control can assist cyclic movements during locomotion of amputee users, the function of these modern devices is still limited due to the lack of neuromuscular control (i.e. control based on human efferent neural signals from the central nervous system to peripheral muscles for movement production). Neuromuscular control signals can be recorded from muscles, called electromyographic (EMG) or myoelectric signals. In fact, using EMG signals for robotic lower limb prostheses control has been an emerging research topic in the field for the past decade to address novel prosthesis functionality and adaptability to different environments and task contexts. The objective of this paper is to review robotic lower limb Prosthesis control via EMG signals recorded from residual muscles in individuals with lower limb amputations.Approach.We performed a literature review on surgical techniques for enhanced EMG interfaces, EMG sensors, decoding algorithms, and control paradigms for robotic lower limb prostheses.Main results.This review highlights the promise of EMG control for enabling new functionalities in robotic lower limb prostheses, as well as the existing challenges, knowledge gaps, and opportunities on this research topic from human motor control and clinical practice perspectives.Significance.This review may guide the future collaborations among researchers in neuromechanics, neural engineering, assistive technologies, and amputee clinics in order to build and translate true bionic lower limbs to individuals with lower limb amputations for improved motor function.


Assuntos
Amputados , Membros Artificiais , Procedimentos Cirúrgicos Robóticos , Eletromiografia , Humanos , Locomoção , Músculo Esquelético
20.
Artigo em Inglês | MEDLINE | ID: mdl-34202488

RESUMO

The purpose of this study was to evaluate the effect of posterior occlusal support of natural teeth and artificial teeth on oral functions and standing motion. Patients who had been treated with removable prostheses were enrolled as the subjects. Their systemic conditions (body mass index (BMI) and skeletal muscle mass index (SMI)) were recorded. The subjects were classified into two groups according to a modified Eichner index: B1-3 (with posterior occlusal support) and B4C (without posterior occlusal support). Maximum occlusal force (MOF), masticatory performance (MP), and standing motion (sway and strength) were evaluated for cases with and without removable prostheses. There were no significant differences in BMI and SMI between the B1-3 group and the B4C group. The subjects with removable prostheses demonstrated significantly higher values in MOF, MP, and sway and strength than the subjects without removable prostheses. The comparison of oral functions between the B1-3 group and the B4C group revealed that the positive effect of posterior occlusal support of natural teeth and removable prostheses and the significant positive effects of posterior occlusal support on standing motion were partly observed in these comparisons. Posterior occlusal support of natural teeth and even of removable prostheses may contribute to the enhancement of oral functions and standing motion.


Assuntos
Membros Artificiais , Prótese Parcial Removível , Arcada Parcialmente Edêntula , Força de Mordida , Humanos , Mastigação
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