Linking AM-PAC Cognition to PROMIS Cognitive Function

Abstract

Objective: To link the Activity Measure for Post-Acute Care (AM-PAC) Applied Cognition to the Patient-Reported Outcomes Measurement Information System (PROMIS) Cognitive Function, allowing for a common metric across scales.

Design: Cross-sectional survey study.

Setting: Outpatient rehabilitation clinics.

Participants: Consecutive sample of 500 participants (N=500) aged ≥18 years presenting for outpatient therapy (physical, occupation, speech).

Interventions: Not applicable.

Main outcome measures: AM-PAC Medicare and Generic Cognition short forms and PROMIS Cognitive Function items representing the PROMIS Cognitive Function item bank.

Results: The calibration of 25 AM-PAC cognition items with 11 fixed PROMIS cognitive function item parameters using item-response theory indicated that items were measuring the same underlying construct (cognition). Both scales measured a wide range of functioning. The AM-PAC Generic Cognitive assessment showed more reliability with lower levels of cognition, whereas the PROMIS Cognitive Function full-item bank was more reliable across a larger distribution of scores. Data were appropriate for a fixed-anchor item response theory-based crosswalk and AM-PAC Cognition raw scores were mapped onto the PROMIS metric.

Conclusions: The crosswalk developed in this study allows for converting scores from the AM-PAC Applied Cognition to the PROMIS Cognitive Function scale.

Keywords: Cognition; Patient-reported outcome measures; Quality of life; Rehabilitation.