Differential item functioning in the Patient Reported Outcomes Measurement Information System Pediatric Short Forms in a sample of children and adolescents with cerebral palsy

Fatigue experienced by people with cerebral palsy: a systematic review of assessment tools and decision tree

PURPOSE

To conduct a systematic review of self- and proxy-report fatigue assessment tools used in studies of people with cerebral palsy (CP) of all ages, and to develop a fatigue assessment tool decision tree for clinicians and researchers.

MATERIALS AND METHODS

Five electronic databases (MEDLINE, PsycInfo, CINAHL, Web of Science and Cochrane) were searched to September 2021 to identify studies assessing self-reported fatigue in people with CP of any age. The assessment tools utilised were extracted and two reviewers appraised the tool characteristics, clinical utility and psychometric properties. A decision tree for selecting fatigue assessment tools was constructed.

RESULTS

Ten assessment tools were identified across thirty-nine studies, three of which are valid and reliable for assessing fatigue severity and impact in people with CP. A four-level fatigue assessment tool decision tree was constructed. No valid and reliable tool for assessing cognitive fatigue was identified; responsiveness has not been evaluated in any tool for people with CP.

CONCLUSIONS

Physical fatigue screening and assessment tools for people with CP are available and are presented in our decision tree, however their utility as outcome measures remains unclear. Cognitive fatigue is understudied and poorly understood, further work is required in this area.

Reliability of the Gait Outcomes Assessment List questionnaire

AIM

To report the test-retest reliability of the parent version of the Gait Outcomes Assessment List (GOAL) questionnaire for item, domain, total score, and goal importance in children with cerebral palsy (CP) functioning in Gross Motor Function Classification System (GMFCS) levels I to III.

METHOD

The GOAL questionnaire was completed twice, 3 to 31 days apart, in a prospective cohort study of 112 caregivers of children aged 4 to 17 years with CP (40% unilateral; GMFCS level I = 53; II = 35; III = 24; 76 males). All had an outpatient visit over a 1-year period. The standard error of measurement (SEM), minimum detectable change, and agreement were calculated for all responses, including goal importance.

RESULTS

The SEM for the total score was 3.1 points for the cohort (GMFCS level I = 2.3, GMFCS level II = 3.8, GMFCS level III = 3.6). The standardized domain and item scores were less reliable than the total score and varied according to GMFCS level. The gait function and mobility domain exhibited the best reliability for the cohort (SEM = 4.4), whereas the use of braces and mobility aids domain exhibited the lowest (SEM = 11.9). Goal importance was reliable (cohort average agreement 73%).

INTERPRETATION

The parent version of GOAL has acceptable levels of test-retest reliability for most domains and items. Caution is advised when interpreting the least reliable scores. Essential information necessary for accurate interpretation is provided.

WHAT THIS PAPER ADDS

The standard error of measurement (SEM) of the Gait Outcomes Assessment List (GOAL) total score was approximately 3 points. The SEM of the GOAL domain score ranged from 4 to 12 points. The use of braces and mobility aids domain had the lowest reliability score. Item-level reliability varied according to domain and Gross Motor Function Classification System level. Caregivers reliably identified item importance with approximately 73% agreement.

Walking speed and patient-reported outcomes in young adults with cerebral palsy

AIM

To examine the relationship between quantitative gait measurements and self-reported physical, psychological, cognitive, and social function status in young adults with cerebral palsy (CP).

METHOD

Seventy-two adults with CP (range 18-48y; median age 23y [interquartile range 21-27y]; 34 males, 38 females), in Gross Motor Function Classification System levels I to IV, who previously underwent an instrumented gait analysis (IGA) at our center as children were recruited. Participants underwent a repeated IGA. National Institutes of Health Patient-Reported Outcomes Information System (PROMIS) instruments including the PROMIS-57, Applied Cognition - General Concerns (Short Form), and Applied Cognition - Executive Function (Short Form) were administered. Data derived from current and prior IGA were compared via non-parametric correlation analysis with PROMIS subscores.

RESULTS

Subscores for anxiety, depression, sleep, and fatigue did not significantly correlate with any IGA data. Walking speed, adjusted for stature, correlated strongly with multiple subscores: physical function (p<0.001, r_s =0.708); participation in social roles (p=0.007, r_s =0.319); executive function (p=0.005, r_s =0.335). Pain interference correlated with longitudinal change in adjusted walking speed (p=0.032, r_s =-0.259). The Applied Cognition - General Concerns (Short Form) correlated with prior absolute walking speed, but not adjusted values.

INTERPRETATION

This study underscores the importance of walking speed and its association with a variety of functional domains in adults with CP.

WHAT THIS PAPER ADDS

Patient-Reported Outcomes Information System measures provide useful clinical data in young adults with cerebral palsy. Temporospatial gait parameters have wide-reaching functional influence in this population. Walking speed is strongly correlated with physical, social, and executive function.

Linking Scores with Patient-Reported Health Outcome Instruments:A VALIDATION STUDY AND COMPARISON OF THREE LINKING METHODS

The psychometric process used to establish a relationship between the scores of two (or more) instruments is generically referred to as linking. When two instruments with the same content and statistical test specifications are linked, these instruments are said to be equated. Linking and equating procedures have long been used for practical benefit in educational testing. In recent years, health outcome researchers have increasingly applied linking techniques to patient-reported outcome (PRO) data. However, these applications have some noteworthy purposes and associated methodological questions. Purposes for linking health outcomes include the harmonization of data across studies or settings (enabling increased power in hypothesis testing), the aggregation of summed score data by means of score crosswalk tables, and score conversion in clinical settings where new instruments are introduced, but an interpretable connection to historical data is needed. When two PRO instruments are linked, assumptions for equating are typically not met and the extent to which those assumptions are violated becomes a decision point around how (and whether) to proceed with linking. We demonstrate multiple linking procedures-equipercentile, unidimensional IRT calibration, and calibrated projection-with the Patient-Reported Outcomes Measurement Information System Depression bank and the Patient Health Questionnaire-9. We validate this link across two samples and simulate different instrument correlation levels to provide guidance around which linking method is preferred. Finally, we discuss some remaining issues and directions for psychometric research in linking PRO instruments.

Measuring Health-Related Quality of Life in Pediatric Neurology

Health-related quality of life (HRQOL) is central to how clinicians and parents make choices about medical care for pediatric neurology patients. To provide parents with the information they need to make these decisions and plan for the future, it is necessary for parents and clinicians to understand how HRQOL is defined and measured in the setting of pediatric neurodevelopmental impairment. We review challenges that exist in measuring HRQOL in pediatric neurology, examine existing measures, and outline key principles to guide selection and interpretation of HRQOL measures in children with neurologic conditions.

Interview Administration of PROMIS Depression and Anxiety Short Forms

BACKGROUND

Health literacy reflects a person's reading and numeracy abilities applied to understanding health-related information. These skills may influence how patients report symptoms, leading to underestimates or overestimates of symptom severity. No prior studies have examined health literacy measurement bias.

OBJECTIVE

The purpose of the current study was to determine whether PROMIS (Patient-Reported Outcomes Measurement Information System) anxiety and depression short forms, administered by interview, capture symptoms equally across health literacy groups. We examined the psychometric properties of PROMIS anxiety and depression short forms using differential item functioning (DIF) analysis by level of health literacy.

METHODS

The sample analyzed included 888 adults, age 55 to 74 years, in Chicago, IL. Health literacy was measured using the Test of Functional Health Literacy in Adults. PROMIS short forms assessed anxiety and depression.

KEY RESULTS

DIF was present in 3 of 8 depression items, and 3 of 7 anxiety items. All items flagged for DIF had lower item-slopes for people with limited health literacy.

CONCLUSIONS

Items with DIF were less strongly related to anxiety and depression, and thus less precise. Overall, impact of DIF on PROMIS scores was negligible, likely mitigated by interview administration. Although overall test impact of health literacy was minimal, DIF analyses flagged items that were potentially too complex for people with limited health literacy. Design and validation of patient-reported surveys should incorporate respondents with a range of health literacy and methods to identify and reduce measurement bias. [HLRP: Health Literacy Research and Practice. 2019;3(3):e196-e204.].

PLAIN LANGUAGE SUMMARY

This study suggests that people with limited health literacy may respond differently to questions about depression and anxiety than people with adequate health literacy. Therefore, it is important to be aware of differences in literacy ability when creating and using questionnaires.

Development of the Pediatric Disability Inventory-Patient Reported Outcome (PEDI-PRO) measurement conceptual framework and item candidates

BACKGROUND

To address the gap in patient reported outcome measures (PROMs) of functional performance appropriate for youth and young adults with developmental disabilities (DD) we developed the Pediatric Evaluation of Disability Inventory-Patient Reported Outcome (PEDI-PRO).

AIM/OBJECTIVE

We used a participatory process to: (1) Develop the measurement conceptual framework; (2) Identify discrete functional tasks to include in the PEDI-PRO; and (3) Refine item candidates.

METHODS

We collaborated with eight youth with DD over 33 months. These youth and university researchers explored the construct of functional performance, developed and refined items, and collected and analyzed data. We also conducted focus groups with youth with DD (n = 62) and rehabilitation professionals (n = 26), and consulted with PEDI measurement experts (n = 3).

RESULTS

Youth's understanding of their functional performance is embedded in their experiences participating in everyday life situations. We developed 78 Daily Activities, 65 Social/Cognitive, and 52 Mobility item candidates that are linked to 11 everyday life situations to assess discrete functional tasks important to youth with DD and rehabilitation professionals.

CONCLUSION AND IMPLICATIONS

As a result of our participatory development process, the PEDI-PRO's proposed conceptual framework and item candidates are grounded in the lived experience of youth with DD.

Examination of psychometric properties of PROMIS®: Pediatric upper limb measures in youth with cerebral palsy

Introduction

This study examines the validity and distribution characteristics of the PROMIS® pediatric upper limb measures in a sample of young people with cerebral palsy.

Method

Data are a cross-sectional subset of a larger prospective study of the responsiveness to change of PROMIS® pediatric measures following surgery to improve functioning in young people with cerebral palsy. Ninety-three participants between the ages of eight and 21 years completed the PROMIS® pediatric mobility and upper limb computer adaptive tests and short forms in conjunction with a set of static “legacy” measures of physical functioning, including a parent-report of upper limb function.

Results

The PROMIS® Pediatric upper limb short form demonstrated acceptable internal consistency (Cronbach’s alpha = 0.85). PROMIS® pediatric upper limb computer adaptive tests and short form mean values (42.1(11) and 43(10.4), respectively) were nearly 1 SD below normal, which is appropriate when a generic measure is used in a sample of young persons with cerebral palsy. The PROMIS® pediatric upper limb computer adaptive tests had a higher frequency of ceiling effects (29.50%) compared to the short form (18.30%).

Conclusion

Results of this study suggest that the PROMIS® pediatric upper limb computer adaptive tests and the short form are valid indicators of upper limb function in young people with cerebral palsy. The item bank can be replenished to address ceiling effects.

Patient-reported outcome measures for young people with developmental disabilities: incorporation of design features to reduce cognitive demands

Use of patient-reported outcome measures (PROMs) may increase the involvement of young people with developmental disabilities in their healthcare decisions and healthcare-related research. Young people with developmental disabilities may have difficulty completing PROMs because of extraneous assessment demands that require additional cognitive processes. However, PROM design features may mitigate the impact of these demands. We identified and evaluated six pediatric PROMs of self-care and domestic life tasks for the incorporation of suggested design features that can reduce cognitive demands. PROMs incorporated an average of 6 out of 11 content, 7 out of 14 layout, and 2 out of 9 administration features. This critical review identified two primary gaps in PROM design: (1) examples and visuals were not optimized to reduce cognitive demands; and (2) administration features that support young people's motivation and self-efficacy and reduce frustration were underutilized. Because assessment demands impact the validity of PROMs, clinicians should prospectively consider the impact of these demands when selecting PROMs and interpreting scores.

WHAT THIS PAPER ADDS

Patient-reported outcome measure (PROM) design features can reduce assessment demands related to cognitive processes. Pediatric PROMs underutilize design features that decrease cognitive demands of self-reporting.

Refining the Pediatric Evaluation of Disability Inventory-Patient-Reported Outcome (PEDI-PRO) item candidates: interpretation of a self-reported outcome measure of functional performance by young people with neurodevelopmental disabilities

AIM

This study examined the item interpretability and rating scale use of the Pediatric Evaluation of Disability Inventory-Patient-Reported Outcome (PEDI-PRO) by young people with developmental disabilities. The PEDI-PRO assesses the functional performance of discrete functional tasks in the context of everyday life situations.

METHOD

A two-phase cognitive interview design was implemented with a convenience sample of 37 young people (mean age 19y, SD 2y 5mo; 13 males and 24 females; 68% with intellectual disability) with developmental disabilities. In phase I, 182 item candidates were each reviewed by an average of four young people. In phase II, 103 items were carried forward or revised and each reviewed by an average of seven additional young people. Two raters coded responses for intended item interpretation and performance quality; codes were analysed using descriptive statistics. Qualitative analysis explored young people's self-evaluation process.

RESULTS

Items were interpreted as intended by most young people (mean 86%). Young people can use PEDI-PRO response categories appropriately to describe their performance: 94% of positive performance descriptions coincided with a positive response category choice; 73% of negative descriptions coincided with a negative response category choice. Young people interpreted items in a literal manner, and their self-evaluation incorporated the use of supports that facilitate functional performance.

INTERPRETATION

The PEDI-PRO's measurement framework appears to support the self-evaluation of functional performance of young people with developmental disabilities.

Identifying Unbiased Items for Screening Preschoolers for Disruptive Behavior Problems

Objective

Efficient identification and referral to behavioral services are crucial in addressing early-onset disruptive behavior problems. Existing screening instruments for preschoolers are not ideal for pediatric primary care settings serving diverse populations. Eighteen candidate items for a new brief screening instrument were examined to identify those exhibiting measurement bias (i.e., differential item functioning, DIF) by child characteristics.

Method

Parents/guardians of preschool-aged children ( N = 900) from four primary care settings completed two full-length behavioral rating scales. Items measuring disruptive behavior problems were tested for DIF by child race, sex, and socioeconomic status using two approaches: item response theory-based likelihood ratio tests and ordinal logistic regression.

Results

Of 18 items, eight were identified with statistically significant DIF by at least one method.

Conclusions

The bias observed in 8 of 18 items made them undesirable for screening diverse populations of children. These items were excluded from the new brief screening tool.