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.

Feasibility of Electromyography-Triggered Neuromuscular Stimulation as an Adjunct to Constraint-Induced Movement Therapy

Background and Purpose. The purpose of this case report is to explore the feasibility of electromyography-triggered neuromuscular stimulation (EMG-stim) as an adjunct to constraint-induced movement therapy (CIMT). Case Description. The patient was a 72-year-old man, 10 years poststroke, who did not meet traditional CIMT criteria. The EMG-stim was applied to the wrist extensors of the patient\u27s weaker arm for one half of the CIMT training hours. Outcomes. The intervention was feasible for this individual. Improvements were observed in motor behavior, quality and amount of use, muscle activity, wrist range of motion, and reaction time of the more-affected extremity. These improvements were paralleled by a change in the size and location of the extensor digitorum communis muscle representation in the primary motor cortex, as measured by transcranial magnetic stimulation mapping. Discussion. These changes suggest that using EMG-stim as an adjunct to CIMT should be further investigated in individuals who have low functional abilities following stroke

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.