Rasch validation of a combined measure of basic and extended daily life functioning after stroke

Background. Tools used to measure poststroke functional status must include basic and instrumental activities of daily living and reflect the patient's and the clinician's perspective of the disease and its effect on daily living performance. Objective. The authors combined the Functional Independence Measure (FIM) and the Nottingham Extended Activities of Daily Living (NEADL) to create a scale providing a comprehensive evaluation of ADLs functional status in patients with stroke. Methods. The study participants were 188 patients completing the FIM and the NEADL. The psychometric properties of the combined measure were examined with Rasch analysis. Results. A 3-point scale and a dichotomous scale were suggested for use in the FIM and the NEADL, respectively. The combined 40 items worked consistently to reflect a single construct, and "bladder management" and "bowel management" were highly related. After "bowel management" was removed from the combined scale, all but 3 items fit the model's expectations, and the 39-item scale showed reasonable item difficulty hierarchy, with high reliability. The 3 misfit items were removed, and no differences in unidimensionality, differential item functioning, and reliability were found between the 36-item and 39-item scales. Conclusions. The combined measure of the FIM and the NEADL provides a comprehensive picture of ADLs. It extends the utility of the FIM and the NEADL and is recommended for use to measure the independence of patients after discharge home.