FUNCTIONAL SCALE DISCRIMINATION AT ADMISSION AND DISCHARGE - RASCH ANALYSIS OF THE LEVEL OF REHABILITATION SCALE-III

Objective: To determine the construct validity of the Level of Rehabil itation Scale-III (LORS-III) with a special focus on this instrument's capability to discriminate rehabilitation inpatient activities of dai ly living (ADL)/mobility and communication/cognition ability at admiss ion and discharge. Design: Rasch analysis of existing data sets in the LORS-III American Data System (LADS). Patients: Existing admission an d discharge data from 3056 rehabilitation inpatients (musculoskeletal injury, cerebrovascular accident, multiple injuries/diseases, brain in jury, neuromuscular disorder, and spinal cord injury) entered into LAD S between April 1992 and January 1993. Main Outcome Measure: LORS-III consists of 17 measurement areas representing abilities in ADL, mobili ty, communication, cognition, and memory. Fourteen of the measurement areas are concurrently scored by a nurse and a specified rehabilitatio n therapist, resulting in a total of 31 items. Results: Consistent wit h findings reported for other functional status measures, the analysis indicated that the LORS-m consists of two unidimensional scales, an A DL/mobility scale, and a communication/cognition scale. Although all s cales fit the Rasch measurement model, the ADL/mobility scale used at admission was most appropriately targeted to the ability level of the sample. At discharge, the ADL scale was generally too easy because the ability level of the sample moved upward towards functional independe nce. The communication/cognition scale at both admission and discharge showed a similar ''ceiling'' effect. Conclusions: These findings indi cate the importance of determining the measurement qualities of functi onal status measures for both admission and discharge ratings. Analyse s, such as Rasch, can provide a logical direction for instrument refin ement. (C) 1995 by the American Congress of Rehabilitation Medicine an d the American Academy of Physical Medicine and Rehabilitation