Measurement Properties of the MPAI-4 in Veterans With mTBI

Objectives To determine whether the measurement properties of the Mayo-Portland Adaptability Inventory Version 4 (MPAI-4) and its participation index (M2PI), which have been adopted as 2 outcome measures in the Veterans Health Administration (VHA) National Polytrauma Rehabilitation Systems of Care, are adequate in veterans with mild traumatic brain injury (mTBI). Design Cross-sectional. Setting Outpatient rehabilitation. Participants Postdeployment veterans with blast-related mTBI (N=177). Intervention Not applicable. Main Outcome Measures Mayo-Portland Adaptability Inventory Version 4 (MPAI-4) and Community Integration Questionnaire (CIQ). Results The unidimensional factor structure of the MPAI-4 total and 3 index scores (abilities, adjustment, participation) were confirmed. Eight of the 30 items were removed for violating monotonicity (6 items) and exceeding Rasch infit (2 items). The rating scale was collapsed from 5 to 3 ratings because of structure issues. The remaining 22 MPAI-4 items demonstrated excellent item/person reliability (0.98/0.91) and separated person ability into 4 strata. Two of the MPAI-4 index scores (abilities and adjustment) had good measurement properties. The third index, M2PI, retained only 3 items that had adequate person reliability (0.75) but separated person ability into only 2 strata. A significant but fair association with the CIQ was demonstrated with the modified MPAI-4. Conclusions The MPAI-4 has been validated in moderate to severe traumatic brain injury but required modification when used in active military personnel with mTBI. We also identified the need for modification of the MPAI-4 to support adequate psychometrics when measuring outcomes in veterans with mTBI. Additional validation of the M2PI is needed in veterans and active military personnel with mTBI, to determine whether the M2PI should continue to be used as an outcome measure in the VHA polytrauma rehabilitation systems.