Lower Limb Prosthesis Users Research Articles

Cross-Cultural Adaptation and Validation of The Nepali Version of The Prosthetic Limb Users Survey of Mobility Short-Form (Plus-M™/Nepali-12Sf) In Lower Limb Prosthesis Users.

Objective mobility measurement of Nepali prosthesis users is lacking. The objective of this study was to cross-culturally adapt, translate and evaluate construct validity of the Prosthetic Limb Users Survey of Mobility (PLUS-M™/Nepali-12 Short Form (SF)) instrument in lower limb prosthesis users residing in Nepal. Two forward translations, review and reconciliation, back translation, expert review, developer review to create the PLUS-M™/Nepali-12SF. Psychometric testing for internal consistency, test-retest reliability and construct validity against the Two-Minute Walk Test (2MWT) and Amputee Mobility Predictor with Prosthesis (AMPPRO) were performed on sixty-six lower limb prosthesis users. The majority of populations were with transtibial amputation 45 (68%), with transfemoral amputation 15 (23%), with knee disarticulation 5 (7.5%) and with syme's amputation 1 (1.5%). The most common cause of amputation among the population was trauma and the least was tumor. Chronbach's alpha for the PLUS-M™/Nepali-12SF was 0.90, mean T-Score was 52.90, test-retest intraclass correlation coefficient (ICC) was 0.94 (95% confidence interval 0.90-0.96). Construct validity with the 2MWT was good (r = 0.62, p< 0.001) and moderately positive with the AMPPRO (r = 0.57, p< 0.001). Our research evidenced that the PLUS-M™/Nepali-12SF had excellent reproducibility. The significance of this work is that it may allow for the measurement of mobility in austere locations of Nepal.

Lower limb prosthesis users' perceptions of everyday life-A phenomenographic study.

A lack of understanding of personal experiences related to limb amputation and prosthetic use limits the extent to which clinicians involved in rehabilitation can support and advise their clients in a person-centered consultation. The objective of this qualitative study was to explore the personal experience of daily life as a lower limb prosthesis user. Fifteen lower limb prosthesis users participated in individual semistructured interviews. Transcripts were analyzed using a phenomenographic approach. The extent to which prosthesis users were able to adjust to their impairment and move on with their life was influenced by social interactions with other prosthesis users, access to relevant information about prosthetic solutions that may benefit them, and finding a balance between desired activities and their physical and/or cognitive capacity. After a period of existential adjustment, prosthesis users described themselves as living active, fulfilling lives. This was facilitated to a large extent by social interactions with other prosthesis users and access to information they perceived as relevant. Social media plays a particularly important role in establishing connections with other prosthesis users and is perceived as a useful source of information.

Creating Adjusted Scores Targeting mobiLity Empowerment (CASTLE 1): determination of normative mobility scores after lower limb amputation for each year of adulthood

Purpose As United States healthcare transitions from traditional fee-for-service models to value-based care, there is increased need to demonstrate quality care through clinical outcomes. Therefore, the purpose of this study was to create equations to calculate an expected mobility score for lower limb prosthesis users specific to their age, etiology, and amputation level to provide benchmarks to qualify good outcomes. Materials and Methods A retrospective cross-sectional analysis of outcomes collected during clinical care was performed. Individuals were grouped based on amputation level (unilateral above-knee (AKA) or below-knee (BKA)) and etiology (trauma or diabetes/dysvascular (DV)). The mean mobility score (PLUS-M® T-score) for each year of age was calculated. AKAs were further stratified into having a microprocessor knee (MPK) or non-microprocessor (nMPK) for secondary analysis. Results As expected, average prosthetic mobility declined with age. Overall, BKAs had higher PLUS-M T-scores compared to AKAs and trauma etiologies had higher scores compared to DV. For AKAs, those with a MPK had higher T-scores compared to those with a nMPK. Conclusions Results from this study provide average mobility for adult patients across every year of life. This can be leveraged to create a mobility adjustment factor to qualify good outcomes in lower limb prosthetic care. IMPLICATIONS FOR REHABILITATION Normative values of mobility are needed to qualify good outcomes in prosthetic care as healthcare shifts towards value-based care. Understanding where an individual is relative to others with similar characteristics (e.g., age, etiology, gender, amputation level, and device type) can provide clinicians with better benchmarks for individual goal-setting. The ability to generate predicted mobility scores specific to each individual can create a mobility adjustment factor to better qualify good outcomes.

After scaling to body size hip strength of the residual limb exceeds that of the intact limb among unilateral lower limb prosthesis users

BackgroundHip muscles play a prominent role in compensating for the loss of ankle and/or knee muscle function after lower limb amputation. Despite contributions to walking and balance, there is no consensus regarding hip strength deficits in lower limb prosthesis (LLP) users. Identifying patterns of hip muscle weakness in LLP users may increase the specificity of physical therapy interventions (i.e., which muscle group(s) to target), and expedite the search for modifiable factors associated with deficits in hip muscle function among LLP users. The purpose of this study was to test whether hip strength, estimated by maximum voluntary isometric peak torque, differed between the residual and intact limbs of LLP users, and age- and gender-matched controls.MethodsTwenty-eight LLP users (14 transtibial, 14 transfemoral, 7 dysvascular, 13.5 years since amputation), and 28 age- and gender-matched controls participated in a cross-sectional study. Maximum voluntary isometric hip extension, flexion, abduction, and adduction torque were measured with a motorized dynamometer. Participants completed 15 five-second trials with 10-s rest between trials. Peak isometric hip torque was normalized to body mass × thigh length. A 2-way mixed-ANOVA with a between-subject factor of leg (intact, residual, control) and a within-subject factor of muscle group (extensors, flexors, abductors, adductors) tested for differences in strength among combinations of leg and muscle group (α = 0.05). Multiple comparisons were adjusted using Tukey’s Honest-Difference.ResultsA significant 2-way interaction between leg and muscle group indicated normalized peak torque differed among combinations of muscle group and leg (p < 0.001). A significant simple main effect of leg (p = 0.001) indicated peak torque differed between two or more legs per muscle group. Post-hoc comparisons revealed hip extensor, flexor, and abductor peak torque was not significantly different between the residual and control legs (p ≥ 0.067) but torques in both legs were significantly greater than in the intact leg (p < 0.001). Peak hip abductor torque was significantly greater in the control and residual legs than the intact leg (p < 0.001), and significantly greater in the residual than control leg (p < 0.001).ConclusionsOur results suggest that it is the intact, rather than the residual limb, that is weaker. These findings may be due to methodological choices (e.g., normalization), or biomechanical demands placed on residual limb hip muscles. Further research is warranted to both confirm, expand upon, and elucidate possible mechanisms for the present findings; and clarify contributions of intact and residual limb hip muscles to walking and balance in LLP users.Clinical Trial RegistrationN/A.

Development of an item bank for measuring prosthetic mobility in people with lower limb amputation: The Prosthetic Limb Users Survey of Mobility (PLUS-M).

Achieving mobility with a prosthesis is a common post-amputation rehabilitation goal and primary outcome in prosthetic research studies. Patient-reported outcome measures (PROMs) available to measure prosthetic mobility have practical and psychometric limitations that inhibit their use in clinical care and research. To develop a brief, clinically meaningful, and psychometrically robust PROM to measure prosthetic mobility. A cross-sectional study was conducted to administer previously developed candidate items to a national sample of lower limb prosthesis users. Items were calibrated to an item response theory model and two fixed-length short forms were created. Instruments were assessed for readability, effective range of measurement, agreement with the full item bank, ceiling and floor effects, convergent validity, and known groups validity. Participants were recruited using flyers posted in hospitals and prosthetics clinics across the United States, magazine advertisements, notices posted to consumer websites, and direct mailings. Adult prosthesis users (N=1091) with unilateral lower limb amputation due to traumatic or dysvascular causes. Not applicable. Candidate items (N=105) were administered along with the Patient Reported Outcome Measurement Information System Brief Profile, Prosthesis Evaluation Questionnaire - Mobility Subscale, and Activities-Specific Balance Confidence Scale, and questions created to characterize respondents. A bank of 44 calibrated self-report items, termed the Prosthetic Limb Users Survey of Mobility (PLUS-M), was produced. Clinical and statistical criteria were used to select items for 7- and 12-item short forms. PLUS-M instruments had an 8th grade reading level, measured with precision across a wide range of respondents, exhibited little-to-no ceiling or floor effects, correlated expectedly with scores from existing PROMs, and differentiated between groups of respondents expected to have different levels of mobility. ThePLUS-M appearstobe well suited to measuring prosthetic mobility in people with lower limb amputation. PLUS-M instruments are recommended for use in clinical and research settings.

Prevalence of secondary prosthesis use in lower limb prosthesis users

Purpose Prostheses designed for daily use are often inappropriate for high-level activities and/or are susceptible to water damage and mechanical failure. Secondary prostheses, such as activity-specific or back-up prostheses, are typically required to facilitate uninterrupted participation in desired life pursuits. This study estimated the prevalence of secondary prosthesis use in a large, national sample of lower limb prosthesis users (LLPUs). Methods We conducted a secondary analysis of survey data from three cross-sectional studies that assessed mobility in LLPUs. Descriptive statistics were used to determine the percentage of secondary prosthesis users and percentages of LLPUs that used different type(s) of secondary prosthesis(es). Secondary prosthesis users and non-users were compared to identify differences in participant characteristics between groups. Results Of participants in the analysis (n = 1566), most (65.8%) did not use a secondary prosthesis. The most common secondary prosthesis types were back-up (19.2%) and activity-specific prostheses (13.5%). Secondary prosthesis users differed significantly from non-users with respect to gender, race, and other characteristics. Conclusions Results suggest that secondary prosthesis use for most LLPUs is limited and may differ based on users’ demographic and clinical characteristics. Future research should determine how LLPUs’ health-related quality-of-life outcomes are affected by access to and use of secondary prostheses. Implications for Rehabilitation Secondary prostheses, including activity-specific, back-up, and shower prostheses, have the potential to improve function, mobility, and participation for people who use lower limb prostheses. Most lower limb prosthesis users do not use secondary prostheses, and access to these devices may be related to users’ demographic and clinical characteristics. Rehabilitation professionals play a key role in facilitating prosthesis users’ access to secondary prostheses and should advocate for those who need them.

GGEM: Gender, Geography, and EMployment differences based on mobility levels among lower limb prosthesis users living in the United States.

For individuals with a disability, an increase in functional mobility may improve their quality of life and well-being. Greater understanding is needed on how factors such as gender, geography, and employment may play a role in mobility levels among individuals with lower limb amputation. To assess the relationship between gender, geography, and employment status on mobility among lower limb prosthesis users. A cross-sectional analysis of 7,524 patient mobility outcomes completed across the United States was performed. The regression model included the independent variables, such as age, gender, region, employment status, and amputation level. Mobility was entered as the dependent variable. Individuals who were employed had 3.6 times the odds of reaching increased mobility (Prosthetic Limb Users' Survey of Mobility ≥ 50) than those unemployed (odds ratio 3.56, 95% confidence interval 3.10-4.09). Gender and geography were significantly associated with mobility as well. Being employed is associated with greater odds of reaching increased mobility. Addressing factors such as returning to employment may aid in improving mobility levels among prosthesis users.

Modifying the five-time sit-to-stand test to allow use of the upper limbs: Assessing initial evidence of construct validity among lower limb prosthesis users.

The Five-time Sit-to-Stand (5xSTS) Test is a performance-based measure used by clinicians and researchers to assess the body functions needed to accomplish sit-to-stand transitions (e.g., lower limb strength, balance, and trunk control). The current requirements for performance of the 5xSTS Test (i.e., crossing arms over the chest) may not be appropriate for many, if not most lower limb prosthesis (LLP) users. The study aims were to (1) develop a modified five-time sit-to-stand (m5xSTS) Test protocol; (2) to examine initial evidence of known-groups construct validity among LLP users by comparing differences in performance by amputation level, amputation etiology, and functional level; and (3) to assess initial evidence of convergent construct validity by examining the correlations between m5xSTS performance with self-reported mobility (Prosthetic Limb Users Survey of Mobility (PLUS-M)), self-reported balance confidence (Activities-balance Confidence Scale (ABC)) and functional capability (comfortable walking speed). Three-hundred sixty-one LLP users participated in this cross-sectional study. The investigators developed a m5xSTS Test protocol that allows tested individuals to use different assistance strategies (i.e., use of upper limbs to push off thighs, push up from the armrests, or use a walker) when needed to perform the test. The investigators recorded m5xSTS Test times and assistance strategies. Significant differences in m5xSTS Test times were found between those who did and did not use an assistance strategy, as well as between participants grouped by different amputation level, etiology, and functional level. Significant moderate negative correlations were found between m5xSTS Test times and PLUS-M T-score (ρ = -0.42, p<0.001), ABC score (ρ = -0.42, p<0.001), and comfortable walking speed (ρ = -0.64, p<0.001), respectively. The m5xSTS Test allows LLP users to perform sit-to-stand transitions in a manner that accounts for their functional impairments, is consistent with post-amputation training, and is safe for the tested individual. Results from this study provide preliminary evidence of known groups and convergent construct validity for the m5xSTS Test with a large national sample of LLP users.

Validity and Reliability of Inertial Measurement Unit (IMU)-Derived 3D Joint Kinematics in Persons Wearing Transtibial Prosthesis.

A validity and reliability assessment of inertial measurement unit (IMU)-derived joint angular kinematics during walking is a necessary step for motion analysis in the lower extremity prosthesis user population. This study aimed to assess the accuracy and reliability of an inertial measurement unit (IMU) system compared to an optical motion capture (OMC) system in transtibial prosthesis (TTP) users. Thirty TTP users were recruited and underwent simultaneous motion capture from IMU and OMC systems during walking. Reliability and validity were assessed using intra- and inter-subject variability with standard deviation (S.D.), average S.D., and intraclass correlation coefficient (ICC). The intra-subject S.D. for all rotations of the lower limb joints were less than 1° for both systems. The IMU system had a lower mean S.D. (o), as seen in inter-subject variability. The ICC revealed good to excellent agreement between the two systems for all sagittal kinematic parameters. All joint angular kinematic comparisons supported the IMU system's results as comparable to OMC. The IMU was capable of precise sagittal plane motion data and demonstrated validity and reliability to OMC. These findings evidence that when compared to OMC, an IMU system may serve well in evaluating the gait of lower limb prosthesis users.

User-relevant factors influencing the prosthesis use of persons with a transfemoral amputation or knee-disarticulation: A meta-synthesis of qualitative literature and focus group results.

Persons with a transfemoral amputation or knee-disarticulation are heavily reliant on an adequate set of components for their prosthesis. To improve the process of adjusting the specific prosthetic properties to the expectations of the prosthesis users, it is of importance to first identify which factors have an influence on prosthesis use. Therefore, we aimed to identify factors that influence prosthesis use in adults with a transfemoral amputation or knee-disarticulation. A qualitative meta-synthesis was conducted by searching five databases (last update January 20th 2022). Studies were considered eligible if they contained qualitative data about adult persons with a transfemoral amputation or knee-disarticulation with experience in using a prosthesis and focused on the users' opinions. All eligible studies were independently screened by two reviewers. The results sections of the included studies were entered in Atlas.ti software (v8) and coded using the framework approach. The quality of the included studies was assessed using the Critical Appraisal Skills Program (CASP) qualitative research checklist. Results of the meta-synthesis were validated with prosthesis users (n = 8) in a focus group. Out of 5757 articles, 14 studies were included. An overview of seven themes ('prosthesis related'; 'rehabilitation, costs and prosthetist'; 'mental'; 'physical'; 'social'; 'activities and participation' and 'walking') containing 84 factors was created. Ten factors were added during the focus group, resulting in an overview of 94 factors that may influence the prosthesis use of lower-limb prosthesis users. Participants would like more user-involvement from the rehabilitation team. The development of a patient decision aid could help this process in the future. The large number of factors demonstrates that there is a great variety between prosthesis users and the factors that influence their prosthesis use. Therefore, it is important to take individual preferences into account for the selection of a new prosthesis.

The experience of sensorimotor integration of a lower limb sensory neuroprosthesis: A qualitative case study.

Lower limb prosthesis users often struggle to navigate uneven terrain or ambulate in low light conditions where it can be challenging to rely on visual cues for balance and walking. Sensory feedback about foot-floor interactions may allow users to reduce reliance on secondary sensory cues and improve confidence and speed when navigating difficult terrain. Our group has developed a Sensory Neuroprosthesis (SNP) to restore sensation to people with lower limb amputation by pairing electrical stimulation of nerves in the residual limb applied via implanted neurotechnology with pressure sensors in the insole of a standard prosthesis. Stimulation applied to the nerves evoked sensations perceived as originating on the missing leg and foot. This qualitative case study reports on the experiences of a 68-year-old with a unilateral trans-tibial amputation who autonomously used the SNP at home for 31 weeks. Interview data collected throughout the study period was analyzed using a grounded theory approach with constant comparative methods to understand his experience with this novel technology and its impacts on his daily life. A conceptual model was developed that explained the experience of integrating SNP-provided sensory feedback into his body and motor plans. The model described the requirements of integration, which were a combination of a low level of mental focus and low stimulation levels. While higher levels of stimulation and focus could result in distinct sensory percepts and various phantom limb experiences, optimal integration was associated with SNP-evoked sensation that was not readily perceivable. Successful sensorimotor integration of the SNP resulted in improvements to locomotion, a return to a more normal state, an enhancement of perceived prosthesis utility, and a positive outlook on the experience. These outcomes emerged over the course of the nearly 8 month study, suggesting that findings from long-term home studies of SNPs may differ from those of short-term in-laboratory tests. Our findings on the experience of sensorimotor integration of the SNP have implications for the optimal training of SNP users and the future deployment of clinical SNP systems for long-term home use.

Rasch validation of the German translation of the Prosthetic Limb Users Survey of Mobility short forms in people with lower limb amputation.

Prostheses are a primary rehabilitative intervention for people after lower limb amputation. To appropriately measure the effectiveness of prosthetic interventions, valid and reliable measures of prosthetic mobility are required. The Prosthetic Limb Users Survey of Mobility (PLUS-M) is a promising instrument for measuring prosthesis users' mobility. However, German translations of the PLUS-M short forms have not yet been validated. Rasch validation of the German translation of the PLUS-M short forms in people with lower limb amputation. This study is based on a cross-sectional survey of prosthesis-using lower limb amputees from a nation-wide cohort. PLUS-M data (the 7-item and the 12-item shortforms; PLUS-M-7 and PLUS-M-12, respectively) from 194 lower limb prosthesis users were subjected to Rasch analysis, an advanced statistical method for assessing if the measurement properties of a questionnaire comply with a wide spectrum of psychometric requirements. Analysis showed appropriate rating scale functioning, good internal construct validity (item fit), unidimensionality, and good targeting of the PLUS-M-7 and PLUS-M-12 short forms. Moreover, the greater conditional measurement precision of PLUS-M-12 (regarding higher test information and lower standard error of mobility estimates) was quantified. Rasch analysis of the German translation of both PLUS-M short forms showed good psychometric qualities. In addition, our study showed that test scores from the PLUS-M-12 are more accurate. Therefore, the PLUS-M-12 is recommended for individual-level clinical applications (e.g., classification or change assessment).

Experiences of lower limb prosthesis users in Kenya: a qualitative study to understand motivation to use and satisfaction with prosthetic outcomes

Purpose To explore the personal and system factors that motivate and enhance outcomes for patients accessing a prosthetic service and using a lower-limb prosthesis within a low resource setting. Materials and methods This study employed a qualitative approach to explore the motivations and satisfaction of individuals with lower limb loss engaging with a prosthetic service in Mombasa, Kenya. In-depth interviews were conducted over Microsoft Teams with 10 lower limb prosthesis users and thematic analysis was applied. Results Five key themes emerged: acceptance, self-determination, hope, clinician relationship and perception. These findings demonstrate the importance of hopeful thinking and a supportive community in overcoming physical and stigmatising challenges. The findings further highlight the value of the service provider relationship beyond just prescribing an assistive device. Conclusion These results have relevance in developing patient-centred services, assistive devices and personnel training that are responsive, motivating, and cognisant of the service user. This is of particular interest as assistive technology services are newly developed in low resource settings. IMPLICATIONS FOR REHABILITATION This research provides an understanding of lower-limb prosthesis users’ satisfaction of a device and motivation for engaging with a prosthetic service within a low resource setting. The relationship the rehabilitation professional has with the service user plays a significant role in facilitating motivation during rehabilitation. Rehabilitation professionals should consider how they can foster a network of support amongst service users when planning services in remote, rural locations. Rehabilitation professionals should be aware of how hopeful thinking can be facilitated during rehabilitation to support motivation. When reviewing the success of services, or designing new service models, the service users should be consulted on what they would deem as a successful outcome.

Rules-Based Real-Time Gait Event Detection Algorithm for Lower-Limb Prosthesis Users during Level-Ground and Ramp Walking.

Real-time gait event detection (GED) using inertial sensors is important for applications such as remote gait assessments, intelligent assistive devices including microprocessor-based prostheses or exoskeletons, and gait training systems. GED algorithms using acceleration and/or angular velocity signals achieve reasonable performance; however, most are not suited for real-time applications involving clinical populations walking in free-living environments. The aim of this study was to develop and evaluate a real-time rules-based GED algorithm with low latency and high accuracy and sensitivity across different walking states and participant groups. The algorithm was evaluated using gait data collected from seven able-bodied (AB) and seven lower-limb prosthesis user (LLPU) participants for three walking states (level-ground walking (LGW), ramp ascent (RA), ramp descent (RD)). The performance (sensitivity and temporal error) was compared to a validated motion capture system. The overall sensitivity was 98.87% for AB and 97.05% and 93.51% for LLPU intact and prosthetic sides, respectively, across all walking states (LGW, RA, RD). The overall temporal error (in milliseconds) for both FS and FO was 10 (0, 20) for AB and 10 (0, 25) and 10 (0, 20) for the LLPU intact and prosthetic sides, respectively, across all walking states. Finally, the overall error (as a percentage of gait cycle) was 0.96 (0, 1.92) for AB and 0.83 (0, 2.08) and 0.83 (0, 1.66) for the LLPU intact and prosthetic sides, respectively, across all walking states. Compared to other studies and algorithms, the herein-developed algorithm concurrently achieves high sensitivity and low temporal error with near real-time detection of gait in both typical and clinical populations walking over a variety of terrains.

Three Trials Are Insufficient To Capture Lower Limb Prosthesis Users' Maximum Hip Extension Strength

Three Trials Are Insufficient To Capture Lower Limb Prosthesis Users' Maximum Hip Extension Strength

A survey for characterizing details of fall events experienced by lower limb prosthesis users.

Despite their importance to fall prevention research, little is known about the details of real-world fall events experienced by lower limb prosthesis users. This gap can be attributed to the lack of a structured, population-specific fall survey to document these adverse health events. The objective of this project was to develop a survey capable of characterizing the circumstances and consequences of fall events in lower limb prosthesis users. Best practices in survey development, including focus groups and cognitive interviews with diverse samples of lower limb prosthesis users, were used to solicit input and feedback from target respondents, so survey content would be meaningful, clear, and applicable to lower limb prosthesis users. Focus group data were used to develop fall event definitions and construct a conceptual fall framework that guided the creation of potential survey questions and response options. Survey questions focused on the activity, surroundings, situation, mechanics, and consequences of fall events. Cognitive interviews revealed that with minor revisions, survey definitions, questions, and response options were clear, comprehensive, and applicable to the experiences of lower limb prosthesis users. Administration of the fall survey to a national sample of 235 lower limb prosthesis users in a cross-sectional preliminary validation study, found survey questions to function as intended. Revisions to the survey were made at each stage of development based on analysis of participant feedback and data. The structured, 37-question lower limb prosthesis user fall event survey developed in this study offers clinicians and researchers the means to document, monitor, and compare fall details that are meaningful and relevant to lower limb prosthesis users in a standardized and consistent manner. Data that can be collected with the developed survey are essential to establishing specific goals for fall prevention initiatives in lower limb prosthesis users.

Comparison of Self-Reported vs Objective Measures of Long-Term Community Ambulation in Lower Limb Prosthesis Users

ObjectiveTo determine normal variation in walking metrics in a population of lower limb amputees who use lower limb prostheses over a 6-month period and to provide a means to interpret clinically meaningful change in those community walking metrics. DesignProspective cohort study monitoring walking behavior and subjective and objective measures of activity. SettingVeterans Administration and university amputee clinics. Participants86 individuals with lower limb amputation who use protheses. InterventionsStepWatch activity monitor tracked subjects’ walking for 24 weeks; Global Mobility Change Rating collected weekly. Main Outcome MeasuresAssociation between change in Global Mobility Change Rating and change in any of the walking metrics. ResultsWalking metrics including step count, cadence, cadence variability, and walking distance in a population of lower limb prosthesis users were obtained. There was a high correlation in the walking metrics indicating higher function with higher functional classification level (K-levels) but also substantial overlap in all metrics and a very weak correlation between subject-reported activity level and objective measures of walking performance. ConclusionThe overlap in walking metrics with all K-levels demonstrates that no single metric measured by StepWatch can determine K-level with 100% accuracy. As previously demonstrated in other populations, subjects’ interpretations of their general activity level was inaccurate, regardless of their age or activity level. Objective measures of walking appear to provide a more accurate representation of patients’ activity levels in the community than self-report. Therefore, objective measures of walking are useful in supporting K-level determinations. However, clinicians cannot rely on a single metric to determine K-level.

A case study on the value of in-socket force measurements in gait monitoring of lower-limb prosthesis users.

Wearable sensors have the potential to drastically improve gait rehabilitation and assessments. This is especially the case for lower limb prosthesis users as small wearables can provide useful information about in-socket conditions. Through a simple case study, we investigated the value of measuring in-socket forces in addition to gait parameters in gauging the effectiveness of a training intervention. The results showed that the additional objective information obtained through in-socket measurements can enhance our understanding of how a particular intervention affects both gait and socket comfort.

Direction of attentional focus in prosthetic training: Current practice and potential for improving motor learning in individuals with lower limb loss.

Adopting an external focus of attention has been shown to benefit motor performance and learning. However, the potential of optimizing attentional focus for improving prosthetic motor skills in lower limb prosthesis (LLP) users has not been examined. In this study, we investigated the frequency and direction of attentional focus embedded in the verbal instructions in a clinical prosthetic training setting. Twenty-one adult LLP users (8 female, 13 male; 85% at K3 level; mean age = 50.5) were recruited from prosthetic clinics in the Southern Nevada region. Verbal interactions between LLP users and their prosthetists (mean experience = 10 years, range = 4-21 years) during prosthetic training were recorded. Recordings were analyzed to categorize the direction of attentional focus embedded in the instructional and feedback statements as internal, external, mixed, or unfocused. We also explored whether LLP users' age, time since amputation, and perceived mobility were associated with the proportion of attentional focus statements they received. We recorded a total of 20 training sessions, yielding 904 statements of instruction from 338 minutes of training. Overall, one verbal interaction occurred every 22.1 seconds. Among the statements, 64% were internal, 9% external, 3% mixed, and 25% unfocused. Regression analysis revealed that female, older, and higher functioning LLP users were significantly more likely to receive internally-focused instructions (p = 0.006, 0.035, and 0.024, respectively). Our results demonstrated that verbal instructions and feedback are frequently provided to LLP users during prosthetic training. Most verbal interactions are focused internally on the LLP users' body movements and not externally on the movement effects. While more research is needed to explore how motor learning principles may be applied to improve LLP user outcomes, clinicians should consider adopting the best available scientific evidence during treatment. Overreliance on internally-focused instructions as observed in the current study may hinder prosthetic skill learning.

Normalization alters the interpretation of hip strength in established unilateral lower limb prosthesis users

BackgroundValid comparisons of muscle strength between individuals or legs that differ in size requires normalization, often by simple anthropometric variables. Few studies of muscle strength in lower-limb prosthesis users have normalized strength data by any anthropometric variable, potentially confounding our understanding of strength deficits in lower-limb prosthesis users. The objective of this pilot study was to determine the need for as well as effectiveness and impact of normalizing hip strength in lower-limb prosthesis users. MethodsPeak isometric hip extension and abduction torques were collected from 28 lower-limb prosthesis users. Allometric scaling was used to determine if hip torque values were significantly associated with, and therefore needed to be adjusted for, body mass, thigh length, or body mass x thigh length, and whether normalization was effective in reducing any associations. Between limb differences in peak hip torque, and correlations with balance ability, were inspected pre- and post-normalization. FindingsHip torques were consistently and significantly associated with body-mass x thigh length. Associations between peak hip torque and body-mass x thigh length were reduced by normalization. After normalization by body-mass x thigh length, between limb differences in hip extension torque, as well as the correlation between hip abduction torque and balance ability, changed from non-significant to significant. InterpretationIn the absence of normalization, hip strength (i.e., peak torque) in lower-limb prosthesis users remains dependent on basic anthropometric variables, masking relationships between hip strength and balance ability, as well as between limb differences.