Carole A. Tucker

Efficacy of clinical gait analysis: A systematic review

The aim of this systematic review was to evaluate and summarize the current evidence base related to the clinical efficacy of gait analysis. A literature review was conducted to identify references related to human gait analysis published between January 2000 and September 2009 plus relevant older references. The references were assessed independently by four reviewers using a hierarchical model of efficacy adapted for gait analysis, and final scores were agreed upon by at least three of the four reviewers. 1528 references were identified relating to human instrumented gait analysis. Of these, 116 original articles addressed technical accuracy efficacy, 89 addressed diagnostic accuracy efficacy, 11 addressed diagnostic thinking and treatment efficacy, seven addressed patient outcomes efficacy, and one addressed societal efficacy, with some of the articles addressing multiple levels of efficacy. This body of literature provides strong evidence for the technical, diagnostic accuracy, diagnostic thinking and treatment efficacy of gait analysis. The existing evidence also indicates efficacy at the higher levels of patient outcomes and societal cost-effectiveness, but this evidence is more sparse and does not include any randomized controlled trials. Thus, the current evidence supports the clinical efficacy of gait analysis, particularly at the lower levels of efficacy, but additional research is needed to strengthen the evidence base at the higher levels of efficacy.

The role of technical advances in the adoption and integration of patient-reported outcomes in clinical care

Background:Patient-reported outcomes (PROs) are gaining recognition as key measures for improving the quality of patient care in clinical care settings. Three factors have made the implementation of PROs in clinical care more feasible: increased use of modern measurement methods in PRO design and validation, rapid progression of technology (eg, touchscreen tablets, Internet accessibility, and electronic health records), and greater demand for measurement and monitoring of PROs by regulators, payers, accreditors, and professional organizations. As electronic PRO collection and reporting capabilities have improved, the challenges of collecting PRO data have changed. Objectives:To update information on PRO adoption considerations in clinical care, highlighting electronic and technical advances with respect to measure selection, clinical workflow, data infrastructure, and outcomes reporting. Methods:Five practical case studies across diverse health care settings and patient populations are used to explore how implementation barriers were addressed to promote the successful integration of PRO collection into the clinical workflow. The case studies address selecting and reporting of relevant content, workflow integration, previsit screening, effective evaluation, and electronic health record integration. Conclusions:These case studies exemplify elements of well-designed electronic systems, including response automation, tailoring of item selection and reporting algorithms, flexibility of collection location, and integration with patient health care data elements. They also highlight emerging logistical barriers in this area, such as the need for specialized technological and methodological expertise, and design limitations of current electronic data capture systems.

Recovery from perturbations during paced walking

The aim of the current study was to develop a safe, standardized, stability test and to explore a set of metrics to characterize the recovery of gait stability in healthy individuals following a single mechanical perturbation during steady locomotion. Balance perturbations were mechanically applied to the right foot of 12 healthy subjects during paced walking by translating a platform embedded in a 12 m walkway diagonally (+45/-135 degrees ) relative to the direction of travel approximately 200 ms after heel strike. We examined the medio-lateral (ML) displacement of the sternum before, during and after the platform translation. Measurements of ML position of the right and left shanks in relation to the position of the sternum were used as step-by-step estimates of the moment arm controlling ML motion of the body. We hypothesized that when gait is perturbed in the single stance phase of the step cycle via a translation of the support surface, a series of steps after the perturbation input will be altered reflecting an effort by the CNS to maintain the center of mass (COM) within the base of support and to stabilize the upper body for continued gait. Specifically, if the foot is perturbed laterally during mid-stance a widening of the upcoming step will occur and if the foot is perturbed medially a narrowing of the upcoming step will occur. This behavior was frequent for most subjects. Recovery of non-perturbation behavior was achieved on the third step after the platform translation. An additional strategy was seen for some subjects during lateral perturbation inputs. Instead of widening the upcoming step, these subjects acquired the support to stabilize the body by putting their left foot down very quickly with minimal change in stance width. The recovery profiles of the sternum, though directionally asymmetric, were similar in shape among subjects and roughly proportional to the magnitude of the platform translation. Five to six steps were required for complete recovery in the subjects tested in this study.

Effects of a supported speed treadmill training exercise program on impairment and function for children with cerebral palsy

Aim  To compare the effects of a supported speed treadmill training exercise program (SSTTEP) with exercise on spasticity, strength, motor control, gait spatiotemporal parameters, gross motor skills, and physical function.

Evaluation of an Item Bank for a Computerized Adaptive Test of Activity in Children With Cerebral Palsy

Background: Contemporary clinical assessments of activity are needed across the age span for children with cerebral palsy (CP). Computerized adaptive testing (CAT) has the potential to efficiently administer items for children across wide age spans and functional levels. Objective: The objective of this study was to examine the psychometric properties of a new item bank and simulated computerized adaptive test to assess activity level abilities in children with CP. Design: This was a cross-sectional item calibration study. Methods: The convenience sample consisted of 308 children and youth with CP, aged 2 to 20 years (X=10.7, SD=4.0), recruited from 4 pediatric hospitals. We collected parent-report data on an initial set of 45 activity items. Using an Item Response Theory (IRT) approach, we compared estimated scores from the activity item bank with concurrent instruments, examined discriminate validity, and developed computer simulations of a CAT algorithm with multiple stop rules to evaluate scale coverage, score agreement with CAT algorithms, and discriminant and concurrent validity. Results: Confirmatory factor analysis supported scale unidimensionality, local item dependence, and invariance. Scores from the computer simulations of the prototype CATs with varying stop rules were consistent with scores from the full item bank (r=.93–.98). The activity summary scores discriminated across levels of upper-extremity and gross motor severity and were correlated with the Pediatric Outcomes Data Collection Instrument (PODCI) physical function and sports subscale (r=.86), the Functional Independence Measure for Children (Wee-FIM) (r=.79), and the Pediatric Quality of Life Inventory–Cerebral Palsy version (r=.74). Limitations: The sample size was small for such IRT item banks and CAT development studies. Another limitation was oversampling of children with CP at higher functioning levels. Conclusions: The new activity item bank appears to have promise for use in a CAT application for the assessment of activity abilities in children with CP across a wide age range and different levels of motor severity.

Analysis of the pediatric outcomes data collection instrument in ambulatory children with cerebral palsy using confirmatory factor analysis and item response theory methods.

Background: Traditional use of the Pediatric Outcomes Data Collection Instrument (PODCI) assumes that all items have the same structure, are measuring the intended constructs, and assess the right levels of function to show change after orthopaedic or neurological intervention. Item response theory (IRT) methods can statistically account for inherent differences in PODCI item characteristics and thus reveal attributes of the measure important to effectiveness research. Our study uses IRT methods to determine whether PODCI items fit the projected dimensional structure of the PODCI, assess function on each dimension at the right level for a population of ambulatory children with cerebral palsy (CP), and reveal changes after intervention in this population. Methods: Proxy-reported PODCI questionnaires for 570 ambulatory children with CP were randomly divided into 2 groups for model creation and model testing using exploratory and then confirmatory factor analysis. The resulting model was compared with the projected dimensional structure, tested for fit of individual items, and examined for gaps and ceiling effects. Response changes at 1 year were compared between those with (n = 91) and without (n = 284) surgical intervention using paired t tests. Results: Factor analysis reduced the projected dimensions from 5 to 4 for this population, resulting in dimensions for mobility, upper extremity function (UEF), comfort and general health, and self-worth. All but 3 items fit their respective dimensions; ceiling effects were noted in 3 dimensions. Responses showed changes in the comfort and general health, mobility, and UEF dimensions in those who had surgery; in those children who did not have surgery, only the UEF responses changed. Conclusions: The PODCI can show change after intervention when data are analyzed using IRT methods. Ceiling effects in 3 dimensions may limit the amount of change the PODCI can show in a population of ambulatory children with CP. Level of Evidence: Level II. This was a retrospective investigation of a diagnostic tool, the PODCI, using a randomized cross-sectional design for model development, and a case-control design to assess sensitivity to change.

Measuring global physical health in children with cerebral palsy: illustration of a multidimensional bi-factor model and computerized adaptive testing

PurposeThe purposes of this study were to apply a bi-factor model for the determination of test dimensionality and a multidimensional CAT using computer simulations of real data for the assessment of a new global physical health measure for children with cerebral palsy (CP).MethodsParent respondents of 306 children with cerebral palsy were recruited from four pediatric rehabilitation hospitals and outpatient clinics. We compared confirmatory factor analysis results across four models: (1) one-factor unidimensional; (2) two-factor multidimensional (MIRT); (3) bi-factor MIRT with fixed slopes; and (4) bi-factor MIRT with varied slopes. We tested whether the general and content (fatigue and pain) person score estimates could discriminate across severity and types of CP, and whether score estimates from a simulated CAT were similar to estimates based on the total item bank, and whether they correlated as expected with external measures.ResultsConfirmatory factor analysis suggested separate pain and fatigue sub-factors; all 37 items were retained in the analyses. From the bi-factor MIRT model with fixed slopes, the full item bank scores discriminated across levels of severity and types of CP, and compared favorably to external instruments. CAT scores based on 10- and 15-item versions accurately captured the global physical health scores.ConclusionsThe bi-factor MIRT CAT application, especially the 10- and 15-item versions, yielded accurate global physical health scores that discriminated across known severity groups and types of CP, and correlated as expected with concurrent measures. The CATs have potential for collecting complex data on the physical health of children with CP in an efficient manner.

Concept Analysis of the Patient Reported Outcomes Measurement Information System (PROMIS®) and the International Classification of Functioning, Disability and Health (ICF)

PurposeThe Patient Reported Outcomes Measurement Information System (PROMIS®) is a US National Institutes of Health initiative that has produced self-report outcome measures, using a framework of physical, mental, and social health defined by the World Health Organization in 1948 (WHO, in Preamble to the Constitution of the World Health Organization as adopted by the International Health Conference, New York, 1948). The World Health Organization’s International Classification of Functioning, Disability and Health (ICF) is a comprehensive classification system of health and health-related domains that was put forward in 2001. The purpose of this report is to compare and contrast PROMIS and ICF conceptual frameworks to support mapping of PROMIS instruments to the ICF classification system .MethodsWe assessed the objectives and the classification schema of the PROMIS and ICF frameworks, followed by content analysis to determine whether PROMIS domain and sub-domain level health concepts can be linked to the ICF classification.ResultsBoth PROMIS and ICF are relevant to all individuals, irrespective of the presence of health conditions, person characteristics, or environmental factors in which persons live. PROMIS measures are intended to assess a person’s experiences of his or her health, functional status, and well-being in multiple domains across physical, mental, and social dimensions. The ICF comprehensively describes human functioning from a biological, individual, and social perspective. The ICF supports classification of health and health-related states such as functioning, but is not a specific measure or assessment of health, per se. PROMIS domains and sub-domain concepts can be meaningfully mapped to ICF concepts.ConclusionsTheoretical and conceptual similarities support the use of PROMIS instruments to operationalize self-reported measurement for many body function, activity and participation ICF concepts, as well as several environmental factor concepts. Differences observed in PROMIS and ICF conceptual frameworks provide a stimulus for future research and development.

Gillette Functional Assessment Questionnaire 22-item skill set: factor and Rasch analyses

Aim  To determine dimensionality and item‐level properties of the Gillette Functional Assessment Questionnaire (FAQ) 22‐item skill set using factor and Rasch analyses.

Development of a parent-report computer-adaptive test to assess physical functioning in children with cerebral palsy II: upper-extremity skills

The specific aims of this study were to (1) examine the psychometric properties (unidimensionality, differential item functioning, scale coverage) of an item bank of upper‐extremity skills for children and adolescents with cerebral palsy (CP); (2) evaluate a simulated computer‐adaptive test (CAT) using this item bank; (3) examine the concurrent validity of the CAT with the Pediatric Outcomes Data Collection Instrument (PODCI) upper‐extremity core scale; and (4) determine the discriminant validity of the simulated CAT with Manual Ability Classification System (MACS) levels and CP type (i.e. diplegia, hemiplegia, or quadriplegia). Parents (n=180) of children and adolescents with CP (spastic diplegia 49%, hemiplegia 22%, or quadriplegia 28%) consisting of 102 males and 78 females with a mean age of 10 years 6 months (SD 4y 1mo, range 2–21y), and MACS levels I through V participated in calibration of an item pool and completed the PODCI. Confirmatory factor analyses supported a unidimensional model using 49 of the 53 upper‐extremity items. Simulated CATs of 5, 10, and 15 items demonstrated excellent accuracy (intraclass correlation coefficient [ICCs] >0.93) with the full item bank, had high correlations with the PODCI upper‐extremity core scale score (ICC 0.79), and discriminated among MACS levels. The simulated CATs demonstrated excellent overall content coverage over a wide age span and severity of upper‐extremity involvement. The future development and refinement of CATs for parent report of physical function in children and adolescents with CP is supported by our work.