Outcome measures in amputation rehabilitation: ICF body functions.

PURPOSE: To identify and evaluate the lower limb amputation rehabilitation outcome measurement instruments that quantify those outcomes classified within the International classification of functioning, disability and health (ICF) category of body function or structure. This was done to summarise the current evidence base for the most commonly used outcome measurement tools and to provide clinicians with recommendations on how specific tools might be selected for use. METHOD: A systematic review of the literature associated with outcome measurement in lower limb amputation rehabilitation was conducted. Only articles containing data related to metric properties (reliability, validity or responsiveness) for an instrument were included. Articles were identified by electronic and hand-searching techniques and were subsequently classified according to the ICF. RESULTS: Sixteen instruments were identified that were classified into one of Global mental function (12), Sensory and pain (1), Cardiovascular and respiratory (1) and Neuromusculoskeletal and movement (2). Evidence about metric properties and clinical utility was summarised in tables, which formed the basis for conclusions. CONCLUSIONS: Few well-validated body function tools exist in the amputee literature, which may explain their lack of widespread use. For all scales, responsiveness to intervention has not been well established and should be the focus of future studies along with continued establishment of validity and reliability.

Selection of outcome measures in lower extremity amputation rehabilitation: ICF activities.

PURPOSE: To identify and evaluate the lower extremity amputee (LEA) rehabilitation outcome measurement instruments that quantify those outcomes that have been classified within the ICF category of activities. This was done to assist the clinicians in the selection of the most appropriate instrument based upon four determinants of successful LEA rehabilitation and outcome measurement. METHOD: A systematic review of the literature associated with outcome measurement in LEA rehabilitation was conducted. Only articles containing data related to metric properties (reliability, validity or responsiveness) for an instrument were included. Articles were identified by electronic and hand-searching techniques and were subsequently classified first according to the ICF and then by their clinical use. RESULTS: Seventeen instruments were identified that were classified into one of (A) walk tests, (B) mobility grades and (C) indices (generic and amputee-specific). Evidence about metric properties and clinical utility was summarised in tables which formed the basis for conclusions and recommendations pertaining to LEA rehabilitation. CONCLUSIONS: All instruments examined have the potential for some use within the initial rehabilitation trial following amputation. There is a universal absence of quality evidence demonstrating responsiveness and most instruments would benefit from further investigation to better define their optimal use.

Impact of Course Configuration on 6-Minute Walk Test Performance of People with Lower Extremity Amputations.

Purpose: The configuration of the 6-minute walk test (6MWT) may influence the distance walked and comparability of results among subjects and across programmes. The purpose of this study was to evaluate the relative and absolute test-retest reliability of two 6MWT configurations and to evaluate the agreement between these two configurations in users of lower extremity prosthetics. Methods: A cross-sectional design was used to analyze data from 25 subjects completing in-patient prosthetic rehabilitation (mean age 63.12 [SD 13.77] y; 72% male). Two configurations of the 6MWT were examined, and relative and absolute test-retest reliabilities were calculated. Bland-Altman plots were constructed to evaluate agreement between configurations. Results: The relative test-retest reliability was excellent for both Configuration 1 and Configuration 2: ICC 0.97, 95% CI: 0.93, 0.98, and ICC 0.97, 95% CI: 0.94, 0.99, respectively. Comparable values for absolute test-retest reliability were also found. The Bland-Altman plot demonstrated a difference of ±63.92 meters between configurations. Conclusions: The two 6MWT configurations had excellent relative and absolute test-retest reliability, but the results from each configuration do not agree sufficiently to make them interchangeable or directly comparable. This highlights the importance of explicitly indicating the test configuration for the 6MWT when reporting results.

Objectif : la configuration du test de marche de 6 minutes (TM6M) peut influencer la distance marchée et la comparabilité des résultats entre sujets et entre programmes. L'objectif de cette étude était d'évaluer la fiabilité relative et absolue test­retest de deux configurations de TM6M et d'évaluer la concordance de ces deux configurations chez des personnes portant une prothèse à un membre inférieur. Méthodologie : les chercheurs ont analysé les données de 25 sujets suivant une réadaptation prothétique à l'hôpital à l'aide d'une méthodologie transversale (âge moyen de 63,12 [ÉT 13,77] ans; 72 % d'hommes). Ils ont examiné les deux configurations du TM6M et calculé la fiabilité relative et absolue test­retest. Ils ont créé un graphique Bland­Altman pour évaluer la concordance entre les configurations. Résultats : la fiabilité relative test­retest était excellente pour les deux configurations. CIC 0,97; IC à 95 % (0,93; 0,98) et CIC 0,97; IC à 95 % (0,94; 0,99), respectivement. Ils ont aussi observé des valeurs comparables pour la fiabilité absolue test­retest. Le graphique Bland­Altman a révélé une différence de±63,92 m entre les deux configurations. Conclusions : les deux configurations du TM6M ont obtenu une excellente fiabilité relative et absolue test­retest. Cependant, les résultats de chaque configuration ne concordent pas suffisamment pour les rendre interchangeables ou directement comparables. Cette constatation fait ressortir l'importance d'indiquer explicitement la configuration du test pour le TM6M au moment de rendre compte des résultats.

Barriers to outcome measure administration and completion at discharge from inpatient rehabilitation of people with amputation.

We performed a retrospective chart review of consecutive patients discharged from an inpatient amputee rehabilitation program over a 2 yr period (January 2010-December 2011). Our objective was to determine barriers to the completion of a standardized maximum walk test (MWT) at discharge. Over the study period, there were 190 discharges. The sample had a mean age of 63.5 yr (standard deviation [SD] +/- 14.2 yr), was 71.6% male, and had a majority of transtibial amputation (67%). The average length of inpatient stay was 28.1 d (SD +/- 13.2 d). MWT including distance and time was completed in 149 (78%) of the discharges; the main factors limiting patient performance on this measure were cardiorespiratory fatigue (53%), lower-limb pain (24%), back pain (12%), and skin problems (6%). Among those patients who completed the MWT, in 31% no limiting factor was identified. Forty-one discharge MWTs were not completed as a result of nonambulatory status (34%), acute illness (17%), limb pain (7%), skin problems (12%), or other reasons. Knowing these limitations may direct care from a clinical standpoint and provides valuable data for research planning to further examine outcome measures in this population.

The L test of functional mobility: measurement properties of a modified version of the timed "up & go" test designed for people with lower-limb amputations.

BACKGROUND AND PURPOSE: Walk tests provide essential outcome information when assessing ambulation of individuals with lower-limb amputation and a prosthetic device. Existing tests have limitations such as ceiling effects or insufficient challenge. The objective of this study was to assess the reliability and validity of data for a clinical measure of basic mobility, the L Test of Functional Mobility (L Test). SUBJECTS: For this methodological study, 93 people with unilateral amputations (74% transtibial, 26% transfemoral; 78% male, 22% female; mean age=55.9 years) were consecutively recruited from an outpatient clinic. Twenty-seven subjects returned for retesting. METHODS: To assess concurrent validity, subjects completed the L Test, Timed "Up & Go" Test (TUG), 10-Meter Walk Test, and 2-Minute Walk Test, followed by the Activities-specific Balance Confidence scale, Frenchay Activities Index (FAI), and mobility subscale of the Prosthetic Evaluation Questionnaire (PEQ-MS). Amputation cause and level, walking aid use, automatic stepping, and age variables were used to assess discriminant validity. RESULTS: Intraclass correlation coefficients were .96 for interrater reliability and .97 for intrarater reliability, and minimal bias existed upon retesting. The magnitude of concurrent validity correlations (r) was very high between the L Test data and data for other walk tests and fair to moderate between the L Test data and data for self-report measures. The L Test discriminated between all groups as hypothesized. DISCUSSION AND CONCLUSION: The L Test is a 20-m test of basic mobility skills that includes 2 transfers and 4 turns. It demonstrated excellent measurement properties in this study.

Minimal clinically important difference of the L Test for individuals with lower limb amputation: A pilot study.

BACKGROUND: The L Test is a reliable/valid clinical evaluation of mobility that measures walking speed in seconds. It can be used with individuals with lower limb amputation. Responsiveness of the L Test is not yet determined. OBJECTIVES: The purpose of this pilot study was to determine how well the L Test identified individuals with a lower limb amputation who have/have not undergone a minimal clinically important difference. STUDY DESIGN: Prospective follow-up study. METHODS: In total, 33 individuals with lower limb amputation, deemed to require a major intervention, were recruited consecutively from a follow-up clinic. Participants completed the L Test at baseline and follow-up. A Global Rating Change scale was also completed at follow-up. RESULTS: The participants had a mean age ± standard deviation of 60 ± 13.0 years, and 81.8% had a transtibial amputation. The mean ± standard deviation for the L Test change scores was 6.0 ± 13.9. The area under the curve was 0.67, and the minimal clinically important difference was 4.5 s. CONCLUSIONS: The L Test identified individuals as having an important clinical change. Results must be interpreted with caution, as the accuracy, based on the Global Rating Change scale, is low. Further inquiry into the L Test is encouraged. CLINICAL RELEVANCE: The L Test can guide the clinical management of individuals with lower limb amputation. Results from this pilot study indicate that individuals with a lower limb amputation who improve by at least 4.5 s on the L Test after an intervention have likely undergone an important change. This result must be interpreted with caution given that the ability of the L Test to correctly identify individuals, who have and have not undergone an important change, using the Global Rating Change scale as the gold standard, is limited because this is a pilot study. It is plausible that the precision of the cut-point threshold could increase or decrease given a larger sample or when using a different method of identifying important clinical change.

A comparison of psychosocial functioning and personality in amputee and chronic pain populations.

OBJECTIVE: To compare two populations with disabling conditions, amputation and chronic pain, in terms of psychosocial functioning and personality factors. We hypothesized that the degree of disability of amputees would resemble that of patients with chronic musculoskeletal pain. We also examined the prevalence of personality characteristics stereotypic of chronic pain in the two samples. DESIGN: Survey. SETTING: Outpatients at the pain and amputee clinics of a teaching hospital. PATIENTS: Ninety-four patients (47.7% of the number approached) were selected in consecutive samples taken from records and clinics. MAIN OUTCOME MEASURES: Sickness Impact Profile (SIP) and the Millon Clinical Multiaxial Inventory (MCMI). RESULTS: The two groups did not differ on the SIP total score. Sixteen of 47 amputees reported significant pain, and this group showed higher levels of overall disability than did patients with chronic musculoskeletal pain (n = 47) and significantly greater disability than the 31 amputees reporting low levels of pain. Contrary to common perceptions of chronic pain patients, 25% showed no significant evidence of psychopathology. Only anxiety and dysthymia levels were clinically elevated in more than 50% of chronic pain patients. CONCLUSIONS: Results are discussed in terms of the dual disability of amputees with chronic pain and of the hazards of attributing common characteristics to heterogenous patient groups.

Hematometra as a cause of lumbar radiculopathy. A case report.

Low-back pain combined with a positive straight leg raising test (Lasègue's sign) is uncommon in children and adolescents. Reproductive tract (Mullerian) anomalies causing an accumulation of menstrual blood in the vagina, uterus, and fallopian tubes represent an unusual extraspinal cause of low-back pain. The accumulation of blood in these cavities is termed hematocolpos, hematometra, and hematosalpinx. Amenorrhea with cyclic lower abdominal pain and a presenting pelvic mass are the usual presenting features. In the current report, we describe a case of an adolescent with low-back pain, positive straight leg raising test, and signs of L5 radiculopathy that were attributable to hematometra secondary to congenital partial absence of a vagina. This appears to be the first report of this type of presentation.

Balance confidence among people with lower-limb amputations.

BACKGROUND AND PURPOSE: Confidence in a person's balance has been shown to be an important predictor of social activity among people with lower-limb amputations. The purposes of this study were to describe confidence in balance among people with transtibial or transfemoral lower-limb amputations and to compare people whose amputations were due to vascular and nonvascular causes. SUBJECTS AND METHODS: A survey of a sample of 435 community-dwelling individuals from 2 regional clinics was conducted. The sample consisted of people with unilateral transfemoral (26.7%) and transtibial (73.3%) amputations who lost their limb for vascular (53%) and nonvascular (47%) reasons. The mean age of the primarily male (71%) sample was 62.0 years (SD=15.7). RESULTS: Mean scores, using the Activities-specific Balance Confidence (ABC) Scale, were 63.8 for the total sample, 54.1 for the subjects with amputations due to vascular reasons, and 74.7 for the subjects with amputations due to nonvascular reasons. Given a maximum possible ABC Scale score of 100, the results suggest that confidence was low. A difference between the subjects with amputations due to vascular reasons and those with amputations due to nonvascular reasons was observed over each item of the ABC Scale. Variables that were statistically related to balance confidence included age, sex, etiology, mobility device use, the need to concentrate while walking, limitations in activities of daily living, depression, and fear of falling. DISCUSSION AND CONCLUSION: Balance confidence scores among the study sample were low when compared with values previously reported by other researchers. Confidence was particularly low among individuals who had their amputation for vascular reasons. Balance confidence might be an important area of clinical concern.

Rehabilitation potential of elderly patients with major amputations.

This study was undertaken to determine the rehabilitation potential of patients undergoing amputation for vascular disease. A total of 101 patients were studied with a mean age of 69 +/- 14 years, 26 of whom were over age 80. Operative indications were gangrene or ulceration in 80% with rest pain in 20%. Eighteen patients were bilateral amputees. Fifty per cent of the patient population had previous vascular operations. The operative mortality was 13% and was not affected by the age of the patients or the presence of diabetes. Most operative deaths were due to cardiac or septic respiratory complications. Twenty-four of 88 surviving patients were not considered candidates for rehabilitation and the major determining factor was the occurrence of a remote or perioperative stroke. None of these 24 patients was discharged from institutional care. Sixty-four patients were considered rehabilitation candidates with equal distribution in all age groups. Ninety-five per cent of these patients were discharged home with 80% of those patients over 80 being discharged. Eighty-seven per cent of the elderly rehabilitation candidates were fitted with prostheses which compares favourably to other age groups. Seventy-three per cent of the elderly reached their rehabilitation goals (most frequently ambulation with the aid of a walker) which is only slightly less than the younger amputation group. From this study we conclude that amputations which are done for ease of nursing care and patient comfort in debilitated patients have a high mortality rate and rehabilitation goals are unlikely to be met. We have demonstrated high success rates with rehabilitation including patients over age 80. The majority of these patients may be discharged home after a period of aggressive rehabilitation.

A technique to analyse the kinetics and energetics of cane-assisted gait.

UNLABELLED: The purpose of this study was to develop a biomechanical technique to analyse the kinetics of cane-assisted gait. Biomechanical measures such as ground reaction forces (force platforms), cane reaction forces, and kinematics have been routinely measured. However, a full kinetic analysis of both the lower limb and the cane-assisted limb has not been reported: joint reaction forces, moments of force and mechanical powers. Such estimates give the researcher and clinician insight into the levels at each of the joints and the kinetics of the muscles responsible for the altered locomotion and stability. Standard inverse dynamics techniques were employed using a three-dimensional force transducer in the tip of the cane and as the subject walked over a force platform while his movement was recorded on video. Special problems existed when both the cane and foot bore weight on the force platform; the resultant indeterminacy problem was resolved so that independent solutions could be applied to both the lower and upper limbs. RELEVANCE: A full kinetic and energetic biomechanical analysis is needed to identify motor pattern changes at each joint resulting from the use of the cane. Such information will be useful in pinpointing not only motor pattern changes at an affected joint but also adaptive motor pattern changes at other joints. Also, the contribution of the muscles at the wrist, elbow, and shoulder becomes evident not only to the stability of the gait but also to the energetics of forward propulsion.

System for routine assessment of walker-assisted gait.

Strain gauges were built into the legs of a standard aluminium walking frame to simultaneously record forces in three dimensions from all four legs. Preliminary data from six walker-dependent lower-limb amputee subjects suggests that the primary function of a walking frame during ambulation is to enlist the upper extremities to supplement the lower extremities to support body weight. The amplitude and duration of applied forces varied widely from one patient to another. However, repeated strides of individual patients were quite reproducible. Peak vertical walker forces ranged from 33 to 67% body weight and usually occurred during the swing of the least affected leg. Peaks of this magnitude suggest that proper training and evaluation are particularly important for patients whose muscles, joints, and cardiovascular systems have been compromised by disease or prolonged periods of convalescence. Vertical centres of pressure encroached from time to time upon the borders of the walking frame's base of support. Walker stability and patient safety may have been compromised during these periods. A more complete analysis of the magnitude, direction, and point of application of walking frame forces is required before more specific issues of patient safety and stability can be addressed.

Stability of walking frames.

Biomechanical tools were used to assess stability for 11 patients who, following the surgical amputation of one lower limb, required the assistance of a walking frame to ambulate. The Walker Tipping Index (WTI), as derived from the forces applied to the walking frame, was developed specifically for this study to examine the relationship between stability and walking frame height during ambulation. However, the WTI may be useful as a criterion of stability to assist clinicians in their evaluation of walker use in a variety of patient populations. Walker stability was examined as subjects, wearing their prostheses, completed 30-sec walking trials in each of the normal, high, and low walking frame height conditions. Adjusting the height of the walker to one setting (3 cm) above or below normal appears to redistribute the load of walking between the upper and lower extremities without adversely affecting stability.

A prospective study examining balance confidence among individuals with lower limb amputation.

PURPOSE: In this study we assessed whether balance confidence scores changed over a 2-year follow up period, and identified predictors of balance confidence and predictors of change in balance confidence among lower limb amputees. METHOD: A prospective follow-up survey of 245 community living adults with unilateral below and above knee lower limb amputation who used their prosthetic limb daily was conducted. Balance confidence, assessed using the 16-item Activity-specific Balance Confidence (ABC) Scale, socio-demographic, health and amputation related variables were collected at baseline and 2 years later. RESULTS: ABC scores were similar at baseline (mean = 67.6; SD = 25.7) and follow up (mean = 68.0; SD = 25.8). Lower balance confidence scores at follow up were predicted by older age, being female, use of a mobility device, poor perceived health, increased symptoms of depression, having to concentrate while walking, and fear of falling (all p < 0.05). Predictors of change in balance confidence included gender and perceived health (all p < 0.05). CONCLUSION: Balance confidence appears to be a persistent problem in the amputee population. Health professionals are encouraged to consider balance confidence as a potentially important variable that may influence function in this clinically unique group of individuals. The identified predictor variables may be useful to clinicians in targeting individuals who require attention to improve balance confidence.

Comorbidities in amputation: a systematic review of hemiplegia and lower limb amputation.

PURPOSE: The purpose of this review of the scientific literature was to investigate the incidence and prevalence of hemiplegia with lower limb amputation, and to identify outcomes following the dual disability of hemiplegia and amputation. METHODS: Electronic searching of the literature identified major studies examining the effects of hemiplegia on rehabilitation following amputation. Data were extracted and levels of evidence assigned for each subtopic area. RESULTS: The summary conclusions are Level 4 evidence. The prevalence of amputation and hemiplegia is 8-18% and amputation and hemiplegia occur most often in the same leg. Once individuals with hemiplegia and lower limb amputation are selected for prosthetic rehabilitation, rate of successful functional ambulation is greater than 58%. In general there is a lower rate of prosthetic success and independence with hemiplegia than without. Predictive factors associated with success include less severe hemiplegia, laterality of hemiplegia (ipsilateral and right side), transtibial level of amputation and absence of impaired mental function. There is wide variation in length of hospital stay, but a specialty multidisciplinary team reduces length of stay. CONCLUSIONS: Patients with dual disability of hemiplegia and amputation generally benefit from a prosthetic rehabilitation program. Further study on predictive factors for outcome would be beneficial. IMPLICATIONS FOR REHABILITATION: • The prevalence of hemiplegia with lower limb amputation ranges from 8 to 18%, most frequently affecting the same leg. • The majority of patients attain successful functional levels of ambulation with prosthetic rehabilitation, although lower rates than nonhemiplegic patients. • Predictive factors associated with greater success include less severe hemiplegia, ipsilateral hemiplegia, transtibial level of amputation and absence of impaired mental function.

The influence of balance confidence on social activity after discharge from prosthetic rehabilitation for first lower limb amputation.

BACKGROUND: Community living individuals with lower limb amputation have low balance confidence but the level of balance confidence in the first six months after discharge from prosthetic rehabilitation is not known. OBJECTIVES: To determine if balance confidence levels differ after discharge from prosthetic rehabilitation and to determine if balance confidence at discharge predicts social activity at three months post-discharge while controlling for important covariates such as walking ability. STUDY DESIGN: Prospective study. METHODS: Subjects (n = 65) experiencing their first unilateral transfemoral or transtibial amputation were recruited and followed-up one and three months post-discharge. Measures of balance confidence (Activities-specific Balance Confidence Scale) and walking ability (L Test) collected at discharge were used to predict social activity (Frenchay Activities Index) at follow-up. RESULTS: Despite a 14-second mean improvement in walking ability the mean balance confidence scores did not change significantly between discharge (71.2/100) and at three-month follow-up (69.4/100). Confidence scores and basic walking ability at discharge were the two strongest predictors of three-month social activity. Multiple regression modelling indicated that balance confidence and walking ability explained 64% of the variance (standardized beta = 0.34 and -0.37 respectively) in social activity (adjusted R(2) = 39%). CONCLUSIONS: Balance confidence after discharge from prosthetic rehabilitation for lower limb amputation is low and scores do not improve over the first three months post-discharge despite improvements in walking ability. Discharge balance scores confidence independently predicts three-month social activity scores.

Type A personality and marital intimacy in amputees.

The specific characteristics of the Type A personality have generated a great deal of recent attention due to the prevalence of these characteristics in persons suffering from coronary heart disease. Type A individuals are more likely to be involved in serious accidents and experience more secondary complications when faced with serious illness. They are also less apt to incorporate appropriate coping strategies to help deal with pain and discomfort, or to enlist the help of others for such purposes. These studies are particularly interesting for those involved in health care, as such personality characteristics may influence health and healing. The present study examines the Type A personality construct and marital intimacy in a sample of 34 lower extremity amputees. The Survey of Work Styles (SWS) was used to measure Type A behaviour patterns, and the Waring Intimacy Questionnaire (WIQ) to assess the marital relationship. When compared to a group of age- and sex-matched controls, lower extremity amputees showed higher prevalence of some Type A behaviour patterns, and, in males, lower levels of marital intimacy. The low return rate of questionnaires in this study limits its generalizability, but results remain consistent with predictions for Type A behaviour patterns.

Measurement properties of the Frenchay Activities Index among individuals with a lower limb amputation.

OBJECTIVE: To assess the reliability and validity of the original and a modified version of the Frenchay Activities Index (FAI) among individuals with a lower limb amputation. DESIGN: Two week test-retest design. SETTING: South Western Ontario Amputee Program, London, Ontario, Canada. SUBJECTS: Consecutive sample of 84 individuals, primarily men (78.6%), mean age 56.5 years with a unilateral transtibial (71.4%) or transfemoral amputation related to traumatic (59.5%) or vascular causes. INTERVENTIONS: All subjects completed a questionnaire containing the FAI and other scales, the 2-minute walk and timed up and go tests during a regularly scheduled clinic visit. Fifty-five subjects completed a second FAI which was mailed to them two weeks later. Twenty-nine others completed the second FAI upon return for testing related to another project. MAIN MEASURES: FAI, Activity-specific Balance Confidence Scale, Prosthetic Evaluation Questionnaire-Mobility Scale, 2-minute walk, timed up and go and walking device aid use. RESULTS: Relative reliability for the FAI (intraclass correlation coefficient (ICC) = 0.79) and FAI-18 (ICC = 0.78) was acceptable, however bias between measurements was detected. Hypothesized relationships (p < 0.001) between both FAI versions and the Activity-specific Balance Confidence Scale, Prosthetic Evaluation Questionnaire-Mobility Scale, 2-minute walk and timed up and go test were observed. Significant group differences were observed for amputation cause, mobility device use, age and years as an amputee. Neither version distinguished between amputee level or gender groups. CONCLUSIONS: The original and modified FAI are valid and reliable tools for unilateral amputees. Reliability is adequate to detect group but not individual level differences. Additional FAI-18 items did not substantially improve the ability to detect between-amputation-group differences.

Lower extremity prosthetic mobility: a comparison of 3 self-report scales.

OBJECTIVE: To assess and compare the reliability and validity of the Houghton Scale, the Prosthetic Profile of the Amputee Locomotor Capabilities Index (PPA-LCI), and the Prosthetic Evaluation Questionnaire (PEQ) mobility subscale, 3 disease-specific self-report measures of functional mobility for lower extremity prosthetic mobility. DESIGN: Four-week test-retest: 1 sample for reliability analyses, 1 sample for validity analyses. SETTING: University-affiliated outpatient amputee clinic, in Ontario, Canada. PARTICIPANTS: Two outpatient amputee samples (sample 1 [n = 55], for reliability analysis; sample 2 [n = 329], for validity analysis). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Test-retest of reliability and convergent validity of the 3 scales. Convergent validity and discriminative ability were also assessed after setting a priori hypotheses for 2 scales of walking performance, balance confidence, and other indicators of ambulatory ability. RESULTS: The reliability of the PPA-LCI (intraclass correlation coefficient [ICC] = .88) was slightly higher than the Houghton Scale (ICC = .85) and the PEQ mobility subscale (ICC = .77). The PPA-LCI was prone to high ceiling effects (40%) that would limit its ability to detect improvement. Evidence for convergent validity, when compared with the 2-Minute Walk Test, Timed Up and Go, and the Activity-Specific Balance Confidence Scale, was supported as hypothesized in all the scales. Each of the scales was able to discriminate between different groups for amputation cause, walking distance, mobility device use, and automatism, with each having varying strength related to relative precision. The Houghton Scale was the only scale able to distinguish between amputation levels. CONCLUSIONS: Reliability and validity of all the scales are acceptable for group level comparison. None of the scales had clearly superior psychometric properties compared with the others. Further research is required to assess responsiveness.

Psychometric properties of the Activities-specific Balance Confidence Scale among individuals with a lower-limb amputation.

OBJECTIVE: To evaluate the internal consistency, test-retest reliability, and construct validity of the Activities-specific Balance Confidence (ABC) Scale among people who have a lower-limb amputation. DESIGN: Retest design. SETTING: A university-affiliated outpatient amputee clinic in Ontario. PARTICIPANTS: Two samples of individuals who have unilateral transtibial and transfemoral amputation. Sample 1 (n=54) was a consecutive and sample 2 (n=329) a convenience sample of all members of the clinic population. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Repeated application of the ABC Scale, a 16-item questionnaire that assesses confidence in performing various mobility-related tasks. Correlation to test hypothesized relationships between the ABC Scale and the 2-minute walk (2MWT) and the timed up-and-go (TUG) tests; and assessment of the ability of the ABC Scale to discriminate among groups based on amputation cause, amputation level, mobility device use, automatic stepping ability, wearing time, stair climbing ability, and walking distance. RESULTS: Test-retest reliability (intraclass correlation coefficient) of the ABC Scale was .91 (95% confidence interval [CI], .84-.95) with individual item test-retest coefficients ranging from .53 to .87. Internal consistency, measured by Cronbach alpha, was .95. Hypothesized associations with the 2MWT and TUG test were observed with correlations of .72 (95% CI, .56-.84) and -.70 (95% CI, -.82 to -.53), respectively. The ABC Scale discriminated between all groups except those based on amputation level. CONCLUSIONS: Balance confidence, as measured by the ABC Scale, is a construct that provides unique information potentially useful to clinicians who provide amputee rehabilitation. The ABC Scale is reliable, with strong support for validity. Study of the scale's responsiveness is recommended.