Use of Item Response Analysis to Investigate Measurement Properties and Clinical Validity of Data for the Dynamic Gait Index

Background and Purpose. The Dynamic Gait Index (DGI) is a standardized clinical assessment that aids in evaluating a subject’s ability to modify gait in response to changing demands. The purpose of this study was to use Rasch measurement theory to examine whether the DGI rating scale meets suggested psychometric guidelines, whether the hierarchical order of DGI tasks is consistent with a clinically logical testing procedure, and whether the DGI represents a unidimensional construct. Subjects. Subjects were 84 community-dwelling male veterans (age range=64–88 years; mean±SD=75±6.47 years). Methods. Data were retrieved retrospectively from the participants’ clinical records. The Rasch measurement model with the WINSTEPS program was used in this study because it offers distinct advantages over traditional psychometric approaches. Results. Overall, the DGI showed sound item psychometric properties. Each of the original 4 rating scale categories appeared to distinctly identify subjects at different ability levels. The analysis revealed a clear item difficulty hierarchical order that is generally consistent with clinical expectations. In addition, fit statistics and principal components analysis indicated that the 8 items of the DGI appear to represent a single construct. Discussion and Conclusion. The results suggest that the rating scale of the DGI is used appropriately for community-dwelling older subjects with balance problems. The findings support the continued use of this well-constructed scale for clinical and research assessment in a community-dwelling population of older subjects. [Chiu YP, Fritz SL, Light KE, Velozo CA. Use of item response analysis to investigate measurement properties and clinical validity of data for the Dynamic Gait Index. Phys Ther. 2006;86:778–787.

Creation of a short form Boston Naming Test for Individuals with Aphasia

A short form Boston Naming Test (Kaplan, Goodglass, & Weintraub, 1983) has been created using Rasch analysis and responses from neurologically-healthy individuals and individuals with dementia (Graves, Bezeau, Fogarty, & Blair, 2004). Given the differences in the basis of anomia for dementia and aphasia, it cannot be assumed that this form is suitable for both populations. Thus, this study addresses 2 aims: 1) to determine if the Graves et al., (2004) short form is valid in the aphasia population and 2) based on the outcome, to create a 15-item short form with Rasch analysis using data from individuals with aphasia

Stakeholder Recommendations to Refine the Fitness-to-Drive Screening Measure

In developing the web-based Fitness-to-Drive Screening Measure (FTDS) and keyform (results output) for use to identify at-risk older drivers, we examined the needs, perspectives, and suggestions of three stakeholders groups: occupational therapy practitioners, certified driver rehabilitation specialists (CDRSs), and family members/caregivers. We conducted three focus groups, which were moderated, recorded, transcribed, and analyzed using directed content analysis. Respondents in two focus groups also rated FTDS aspects (e.g., ease of use, format, and relevance), using a visual analog scale (VAS, 0-10 scale with 10 being excellent). All three stakeholder groups contributed to the development of the web-based FTDS. Results from occupational therapy practitioners addressed face validity, appearance, wording, and usability; CDRSs informed follow-up recommendations; and family members/caregivers provided keyform feedback. High VAS ratings (\u3e 7 on 1-10 scale) from the CDRSs (8.4, SD+0.8) and family members/caregivers (9.01, SD+1.02) indicated FTDS acceptability. Overall, our findings support the measure’s utility and acceptability among these users. As such, the FTDS may position family members/caregivers to identify at-risk older drivers, facilitate targeted discussions of driving difficulty among occupational therapists and their clients, and afford OT-CDRS an entry point for intervention and clinical decision making

The development of a standardized assessment of phonology in aphasia

The purpose of this paper is to present the conceptual foundation and methodology for the development of the Standardized Assessment of Phonology in Aphasia (SAPA). Item Response Theory (IRT) formed the basis for test construction. A model of phonology was identified, constructs within the model were delineated and items were developed. The SAPA was field tested with 47 individuals with chronic aphasia and IRT statistics were generated to answer research questions. Aphasic performance on the SAPA showed reasonable fit to the Rasch measurement model and results will be discussed in detail

Development of a Social Communication construct for a Computerized Adaptive Measure of Functional Cognition for Traumatic Brain Injury

The study investigated the item-level psychometrics of the Social Communication (SC) construct, one of six constructs that comprise the Computer Adaptive Measure of Functional Cognition for Traumatic Brain Injury (TBI) (CAMFC-TBI). Sixty-nine individuals with TBI (outpatients and 1-year post injury) and 68 caregivers participated. Rasch analysis demonstrated that the SC had sound psychometrics for both groups. Items conformed to the theoretical difficulty hierarchy. Person reliability (comparable to Cronbach’s alpha) was high. Respondents were separated into at least 3 significantly different ability levels. Differential item functioning showed no statistically significant differences between patients and caregivers. These results are promising for inclusion of the SC items in the CAMFC-TBI

The Development of a Standardized Assessment of Phonology in Aphasia: Creating Items to Test Repetition

We are constructing a standardized assessment of phonology in aphasia based on four domains of phonologic processes: concept representation, reading, repetition, and perception. The aim of this paper is to present the results of item development for the repetition domain. Item response theory was the basis of item development and statistical analysis. The final item bank consisted of 113 items which demonstrated sound psychometric properties and adequately measured the range of abilities of our participants with aphasia. The next step in finalizing this domain will focus on shortening the length of the test to include the most salient items

Measurement Properties of the Functional Outcomes Questionnaire for Aphasia

Aphasia often results in negative social, emotional, and financial consequences endorsing rehabilitation efforts that influence communication beyond the level of impairment. The FOQ-A assesses the impact of aphasia treatment on functional communication, extending measurement into activity and participation. The purpose of this study is to evaluate the measurement properties of the FOQ-A in a sample of 127 individuals with moderate to severe aphasia subsequent to stroke. Results of Rasch analysis indicate that the FOQ-A is unidimensional, has good internal consistency, and contains adequate person separation for measuring change after rehabilitation; however, revisions to the scale may improve its usefulness

The Development of a Standardized Assessment of Phonology in Aphasia

The long-term goal of this research is to develop a valid and reliable impairment level measure of phonology in aphasia. The short-term goal, and focus of this abstract, is to present data collected from individuals with aphasia for 3 domains (or subtests) of this assessment: reading, repetition and perception. From the perspective of Item response theory (IRT), procedures will be presented on the development of the item bank. Results pertaining to the psychometric properties of the items when tested on individuals with aphasia show a reasonable fit to the Rasch model. Further research will validate and refine existing items