Policy brief: adaptive cycling equipment for individuals with neurodevelopmental disabilities as durable medical equipment.

- Durable medical equipment (DME) policies require that the equipment be medically necessary; however, adaptive cycling equipment (bicycles and tricycles) are usually not deemed medically necessary. - Individuals with neurodevelopmental disabilities (NDD) are at high risk for secondary conditions, both physical and mental, that can be mitigated by increasing physical activity. - Significant financial costs are associated with the management of secondary conditions. - Adaptive cycling can provide improved physical health of individuals with NDD potentially reducing costs of comorbidities. - Expanding DME policies to include adaptive cycling equipment for qualifying individuals with NDD can increase access to equipment. - Regulations to ensure eligibility, proper fitting, prescription, and training can optimize health and wellbeing. - Programs for recycling or repurposing of equipment are warranted to optimize resources.

Clinical efficacy of instrumented gait analysis: Systematic review 2020 update.

BACKGROUND: This paper updates our 2011 systematic review on the clinical efficacy of three-dimensional instrumented gait analysis (3DGA). RESEARCH QUESTION: What is the current evidence base pertaining to the clinical efficacy of 3DGA? METHODS: We identified English language articles published from September 2009 to October 2019 reporting primary research that used typical motion analysis laboratory methods to study human walking. Five gait laboratory experts classified articles according to the highest type of efficacy they addressed: type 1 (technical), 2 (diagnostic accuracy), 2b (outcome prediction), 3-4 (diagnostic thinking and treatment), 5 (patient outcome), 6 (societal). Articles classified into type 3-4 and higher were rated for quality using LEGEND. RESULTS: Of 2712 articles related to the efficacy of 3DGA, over 99% addressed technical (n = 313), diagnostic (n = 1466), or outcome prediction (n = 927) efficacy. Six type 3-4 studies showed that 3DGA changes treatment plans, increases clinicians' confidence in their treatment decisions, and increases agreement among clinicians. Two type 5 articles based on a randomized controlled trial demonstrated that patient outcomes improved only when 3DGA data were available and its recommendations were followed. A population-based type 5 study found that the incidence of severe crouch gait dropped from 25% to 4% following practice changes including the addition of 3DGA. The strength of evidence was mainly 3b (lesser quality prospective cohort studies) but also included stronger studies (three level 2 controlled clinical trials). SIGNIFICANCE: Literature related to the clinical efficacy of 3DGA has grown substantially over the last decade. Thousands of articles contribute to continued improvement of data collection and interpretation, as well as understanding of gait pathology and treatment. A smaller number of studies clearly demonstrate the efficacy of 3DGA in changing and reinforcing treatment decisions, increasing clinicians' confidence in treatment planning, and increasing agreement among clinicians, as well as the potential to improve patient outcomes.

Evaluation of the treatment of pectus carinatum with compressive orthotic bracing using three dimensional body scans.

PURPOSE: The purpose of this study is to measure the effectiveness of compressive orthotic brace therapy for the treatment of pectus carinatum using an adjusted Haller Index (HI) measurement calculated from 3D body scan (BS) images. METHODS: Pediatric patients with pectus carinatum were treated with either compressive orthotic bracing or observation. An adjusted BS Haller index (HI) was calculated from serial 3D BS images obtained on all patients. Medical records were evaluated to determine treatment with bracing and brace compliance more than 12hours daily. Compliant patient measurements were compared to non-compliant and non-brace groups. RESULTS: Forty patients underwent compressive orthotic bracing, while ten were observed. Twenty-three patients were compliant with bracing, and seventeen patients were non-compliant. Compliant patients exhibited an 8.2% increase, non-compliant patients had a 1.5% increase, and non-brace patients exhibited a 2.5% increase in BS HI. The change in BS HI of compliant patients was significantly different compared to non-brace patients (p=0.004) and non-compliant patients (p<0.001). CONCLUSIONS: Three dimensional BS is an effective, radiation free, and objective means to evaluate patients treated with compressive orthotic bracing.

Gait and participation outcomes in adults with cerebral palsy: a series of case studies using mixed methods.

BACKGROUND: There is a paucity of information on long-term outcomes of adults with cerebral palsy (CP) who received orthopedic interventions in childhood. Clinical effectiveness research requires assessment of outcomes that account for personal and environmental factors that may mediate the effects of treatment, in addition to body structures & function, activity, and participation. OBJECTIVE/HYPOTHESIS: The purpose of this study is to provide a descriptive analysis of characteristics associated with gait and participation outcomes in a series of case studies of adults with CP. METHODS: Participants had follow up gait analysis and clinical evaluation in adulthood and assessment of outcomes with the FIM instrument, the SF-36 Health survey, the Canadian Occupational Performance Measure, and semi-structured questions. RESULTS: Twenty-two out of 26 participants (mean age = 25 years; GMFCS level I (n = 9); II (n = 3); III (n = 11); IV (n = 3)) maintained or improved childhood gait abilities, with levels of participation in society similar to age matched peers. Higher level of severity and personal choices impacted gait abilities in the four who declined. Majority of participants lost range of motion in hip flexion and knee extension, had pain, reported a fitness program, and increased in weight status. Personal factors and environmental factors played a role in both gait and participation outcomes. CONCLUSION: Promotion of fitness activities and social advocacy are warranted for adults with CP. Clinical effectiveness research of long-term impact of orthopedic interventions should account for treatment effects on body structures & function, activity, participation, and modifying effects of personal, and environmental factors.

Rasch analysis of items from two self-report measures of motor function: determination of item difficulty and relationships with children's ability levels.

AIM: The aim of this article was to determine item measurement properties of a set of items selected from the Gillette Functional Assessment Questionnaire (FAQ) and the Pediatric Outcome Data Collection Instrument (PODCI) using Rasch analysis, and to explore relationships between the FAQ/PODCI combined set of items, FAQ walking scale level, Gross Motor Function Classification System (GMFCS) levels, and the Gait Deviation Index on a common measurement scale. METHOD: Rasch analysis was performed on data from a retrospective chart review of parent-reported FAQ and PODCI data from 485 individuals (273 males; 212 females; mean age 9 y 10 mo, SD 3 y 10 mo) who underwent first-time three-dimensional gait analysis. Of the 485 individuals, 289 had a diagnosis of cerebral palsy (104 GMFCS level I, 97 GMFCS level II, 69 GMFCS level III, and 19 GMFCS level IV). Rasch-based person abilities and item difficulties based on subgroups defined by the FAQ walking scale level, Gait Deviation Index, and the GMFCS level were compared. RESULTS: The FAQ/PODCI item set demonstrated necessary Rasch characteristics to support its use as a combined measurement scale. Item groupings at similar difficulty levels were consistent with the mean person abilities of subgroups based on FAQ walking scale level, Gait Deviation Index, and GMFCS level. INTERPRETATION: Rasch-derived person ability scores from the FAQ/PODCI combined item set are consistent with clinical measures. Rasch analysis provides insights that may improve interpretation of the difficulty of motor functions for children with disabilities.

Accuracy, reliability, and validity of a 3-dimensional scanner for assessing torso shape in idiopathic scoliosis.

STUDY DESIGN: Prospective cohort with concurrent controls. OBJECTIVE: To establish accuracy, reliability, and validity of the Vitronic 3D Body Scanner for the evaluation of torso asymmetry in patients with idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Improved appearance is an important expectation of treatment for patients with scoliosis and their parents. Despite being the "gold standard" for quantifying outcomes, Cobb angles do not explain perception of appearance or quality of life. Surface topography is an attractive noninvasive alternative to radiography but has not been studied in the context of patient-centered outcomes. METHODS: Thirty-six adolescents with idiopathic scoliosis undergoing surgical correction had pre- and postoperative radiographs and evaluation of standing posture, torso surface shape, and responses to the Scoliosis Research Society-22 and Spinal Appearance Questionnaire. Twenty-one adolescents without scoliosis were evaluated for comparison. Scanner accuracy was assessed by scanning an object of known dimensions. Within-session reliability of body shape measures constructed from scan data was assessed. Discriminant validity was assessed by examining pre- to postoperative differences. Concurrent validity was examined through correlations of scan measures with radiographs, optoelectronic measures of posture, and self-report responses to the Scoliosis Research Society-22 and Spinal Appearance Questionnaire. RESULTS: Scan system measurement error was 1.74 ± 1.56 mm. Within-session reliability was excellent for the control (intraclass correlation coefficient = 0.83) and scoliosis (intraclass correlation coefficient = 0.94) groups. Medial/lateral torso shift, rotation, and right/left asymmetry differed significantly among the preoperative, postoperative, and control groups (analysis of variance, P < 0.05). Torso asymmetry measures correlated with radiographical measures (r = 0.43-0.51), optoelectronical measures of posture and symmetry (r = 0.33-0.75), and appearance and quality-of-life domains of the Scoliosis Research Society-22 (r = 0.35-0.64) and the Spinal Appearance Questionnaire (r = 0.48-0.67). CONCLUSION: The Vitronic 3D Body Scanner has sufficient accuracy, reliability, and validity to monitor torso asymmetry due to scoliosis. Scan-based measures differentiate between normal and pathological and between preoperative and postoperative body shape and show good correlation with measures of appearance and quality of life.

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.

Factor- and item-level analyses of the 38-item activities scale for kids-performance.

AIM: Children and adolescents highly value their ability to participate in relevant daily life and recreational activities. The Activities Scale for Kids-performance (ASKp) instrument measures the frequency of performance of 30 common childhood activities, and has been shown to be valid and reliable. A revised and expanded 38-item ASKp (ASKp38) version has been reported in recent literature and is currently used in clinical research. The aim of this paper is to assess the factor structure and item-level statistics of the ASKp38. METHOD: Our study used factor analyses and Rasch analyses to determine the item-set dimensionality and to calculate item-level statistics respectively, for existing ASKp38 data from 200 children (104 males; 96 females; mean age 12y 7mo; SD 2y 8mo; range 6-20y) with physical disabilities. The children had a variety of physical impairments including cerebral palsy (n = 105; range 8-13 y), limb salvage (n = 18; range 11-20y), arthrogryposis (n = 13; 6-17y), and other, including individuals with spina bifida and spinal cord injury (n = 64; 8-19 y). RESULTS: A two-factor model, with components of activities of daily living and play, most optimally fit the data. Item-fit statistics based on this two-factor model demonstrated adequate fit and content coverage. INTERPRETATION: The ASKp38 appears to consist of two factors, defined as (1) activities of daily living and (2) play, and may be used to measure the frequency of activity performance on two corresponding subscales.

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. METHOD: A retrospective review of parent-reported FAQ 22-item skill set data was conducted of 485 individuals (273 males, 212 females; mean age 9 y 10 mo, SD 3 y 10 mo), including 289 with cerebral palsy and 196 with a variety of other neuromusculoskeletal conditions with orthopedic impairments. Factor analyses to validate unidimensionality of the skill set and Rasch analyses to determine relative item difficulty, item and test level information, and content coverage of the item set were performed. Differential item functioning analysis of sub-groups based on sex, diagnosis grouping, and age was conducted. Precision of score estimates for the item set was analyzed. RESULTS: The FAQ 22-item skill set demonstrates unidimensional structure and good item fit statistics. No floor or ceiling effects were noted. Differential item functioning (DIF) based on age was noted for seven items, four items showed diagnosis group-related DIF, and one item sex-related DIF. Precision was adequate in the mid-range range of abilities. INTERPRETATION: Based on this analysis, the FAQ 22-item skill set is a hierarchical set of interval scaled items suitable for measuring locomotor skill ability in children.

Walking abilities of young adults with cerebral palsy: changes after multilevel surgery and adolescence.

Although there is some evidence to support the efficacy of single event multilevel surgery (SEMLS) in the short term for improving walking abilities in children with cerebral palsy (CP), long term effects are not known. It is hypothesized: (1) SEMLS improves walking abilities; (2) in young adulthood abilities deteriorate beyond pre-operative status; (3) walking abilities deteriorate from adolescence to young adulthood and are associated with weight status increase. Twenty-three young adults (mean age 25.5 years, range 20-36) with spastic CP Gross Motor Functional Classification Scale Level II (n=11) or III (n=12) returned for follow up three dimensional gait analysis (3DGA). Gillette Gait Index (GGI) was used as a general indicator of walking abilities. Eleven subjects had 3DGA prior to multilevel orthopedic surgery and 12 subjects had 3DGA after the age of 10 with no interventions in the interim. GGI(s) were graphed over time. Ten of 11 subjects (91%) who had multilevel surgery either improved (n=6) or maintained pre-operative walking abilities (n=4) based on GGI. Ten of 12 subjects (83%) who had 3DGA after the age of 10 but no interventions in the interim maintained (n=8) or improved (n=2) walking abilities. No associations were found between declines in walking abilities and increased weight status. After SEMLS, walking abilities in young adulthood were comparable to pre-operative status. A decline in walking abilities was not observed from adolescence to young adulthood.

Precision and content range of a parent-reported item bank assessing lower extremity and mobility skills in children with cerebral palsy.

AIM: The aim of this study was to determine the psychometric properties, content range, and measurement precision of a lower extremity physical functioning and mobility skills item bank (LE85) in children with cerebral palsy (CP). METHOD: Lower extremity functioning and mobility skill items were administered to 308 parents of children (169 males, 139 females; mean age 10y 8mo, SD 4y) with spastic CP (145 diplegia, 73 hemiplegia, 89 quadriplegia; [for one person type of CP was unknown]) classified using the Gross Motor Function Classification System (75 level I, 91 level II, 79 level III, 37 level IV, 26 level V). Additional legacy measures were administered to assess concurrent validity. Psychometric characteristics, differential item functioning, content range, and score precision were examined. RESULTS: The LE85 had acceptable psychometric properties. Content range matched the ability range of the sample population and exceeded legacy measures with minimal differential item functioning. The LE85 had good correlation with the Paediatric Outcomes Data Collection Instrument, Functional Independence Measure for Children, Gillette Functional Assessment Questionnaire, and Paediatric Quality of Life Inventory-CP module (range r=0.63-0.86). Precision of the LE85 and 10-item simulated computer adaptive test scores outperformed legacy measures. INTERPRETATION: The LE85 appears to be suitable to administer as a computer adaptive test to measure lower extremity physical functioning and mobility in children with CP.

Development of a parent-report computer-adaptive test to assess physical functioning in children with cerebral palsy I: lower-extremity and mobility skills.

The objective of this project was to develop computer-adaptive tests (CATs) using parent reports of physical function in children and adolescents with cerebral palsy (CP). The specific aims of this study were to (1) examine the psychometric properties of an item bank of lower-extremity and mobility skills for children with CP; (2) evaluate a CAT using this item bank; (3) examine the concurrent validity of the CAT with the Pediatric Outcomes Data Collection Instrument (PODCI) and the Functional Assessment Questionnaire (FAQ); and (4) establish the discriminant validity of simulated CATs with Gross Motor Function Classification System (GMFCS) levels and CP type (diplegia, hemiplegia, or quadriplegia). Parents (n=190) of children and adolescents with spastic diplegic (48%), hemiplegic (22%), or quadriplegic (30%) CP consisting of 108 males and 82 females with a mean age of 10 years 7 months (SD 4y 1mo, range 2-21y) and in GMFCS levels I to V participated in item pool calibration and completed the PODCI and FAQ. Confirmatory factor analyses supported a unidimensional model for the 45 basic lower-extremity and mobility items. Simulated CATs of 5, 10, and 15 items demonstrated excellent accuracy (intraclass correlation coefficients [ICCs] >0.91) with the full item bank and had high correlations with PODCI transfers and mobility (ICC = 0.86) and FAQ scores (ICC = 0.77). All CATs discriminated among GMFCS levels and CP type. The lower-extremity and mobility skills item bank and simulated CATs demonstrated excellent performance over a wide span of ages and severity levels.

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.

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.

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

PURPOSE: The 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). METHODS: Parent 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. RESULTS: Confirmatory 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. CONCLUSIONS: The 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.

Assessment of the kinematic variability among 12 motion analysis laboratories.

Variability of kinematic measurements among sites participating in a collaborative research investigation is a primary factor in determining number of subjects, level of detectable difference and statistical power of a multi-site research study. In this study, one subject was evaluated by 24 examiners at 12 motion analysis laboratories and the observed variability of nine kinematic parameters are reported. Following implementation of a standardized gait analysis protocol the same subject returned for another evaluation at each of the 12 laboratories. Additionally, system accuracy and variability of the subject within and between test days are included as factors that may affect between site variability. Marker placement among examiners is identified as the largest source of variability. A 20% decrease in variability was noted following implementation of the standardized protocol.

Using cognitive interviewing for test items to assess physical function in children with cerebral palsy.

PURPOSE: The purpose of this study was to assess the content, format, and comprehension of test items and responses developed for use in a computer adaptive test (CAT) of physical function for children with cerebral palsy (CP). METHODS: After training in cognitive interviewing techniques, investigators defined item intent and developed questions for each item. Parents of children with CP (n = 27) participated in interviews probing item meaning, item wording, and response choice adequacy and appropriateness. RESULTS: Qualitative analysis identified 3 themes: item clarity; relevance, context, and attribution; and problems with wording or tone. Parents reported the importance of delineating task components, assistance amount, and environmental context. CONCLUSION: Cognitive interviewing provided valuable information about the validity of new items and insight to improve relevance and context. We believe that the development of CATs in pediatric rehabilitation may ultimately reduce the impact of the issues identified.

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.