Abstract

Rasch analysis is a statistical technique used in determining statistical properties of functional measures for use in research and treatment. The technique was used in the current study to determine the reliability and validity of the Mayo Portland Adaptability Inventory-Version 4 (MPAI-4) for use with three different acquired brain injury samples. Subjects were 777 adults (each group comprised of 259 individuals) with acquired brain injury treated in one of three rehabilitation program types: Neurorehabilitation (NR), Neurobehavioral (NB), or Supported Living (SL). The MPAI-4 was administered to each participant upon admission to program. Rasch analysis was conducted to assess item fit, reliability, and separation statistics for MPAI-4 assessments conducted within each program. Item difficulty values were examined to determine if the MPAI-4 differentiated among groups based on deficit profiles. The results revealed that for each group, fit statistics fell with appropriate levels (0.5 – 1.5) for at least 24 of 29 items. Rasch person reliability statistics were 0.89 for NR and NB, and 0.90 for SL. Item reliability was 0.99 for each of the groups. Item difficulty values accurately differentiated the three groups based on their specific deficit profiles expected. Specifically, NR participants’ greatest deficits demonstrated by the MPAI-4 were within cognitive and physical functions. For the NB participants, the greater deficits demonstrated were within the behavioral and adjustment items. Supported Living participants had the most limitation within the instrumental activities of daily living items. As in prior research findings, the current Rasch analysis supported the use of the MPAI-4 within this heterogeneous, acquired brain injury population. This unique statistical approach translates to treatment priorities that may assist clinicians with identifying treatment goals specific to unique treatment group characteristics (e.g., NR, NB, and SL).

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