Utility of the Activity Measure for Post-acute Care (AM-PAC) as a Measure of Functional Recovery Across the TBI Rehabilitation Continuum

Research Objectives: To evaluate the efficacy of the Activity Measure for Post-Acute Care (AM-PAC) for evaluating functional recovery in patients with Traumatic Brain Injury (TBI) across inpatient and outpatient rehabilitation settings. We assessed (1) Longitudinal changes (1-year) in cognitive and physical functional recovery across the rehabilitation continuum and (2) Concurrent validity of the AM-PAC as compared to other traditional measures.

Design: A 1 year prospective repeated measures cohort study.

Setting: Setting: Suburban academic medical center with acute inpatient and outpatient rehabilitation facilities.

Participants: Participants: Adults (N=186) with mild and moderate to severe TBI receiving acute inpatient rehabilitation (N=87) and outpatient cognitive rehabilitation (N=99).

Interventions: Interventions: Not applicable.

Main Outcome Measures: Main Outcome Measures: Assessment was conducted at admission, and discharge from inpatient/outpatient rehabilitation and at 6 months and 1 year post-injury. Standardized Response Mean (SRM), Effect Size (ES), and Minimum Detectable Change (MDC) were calculated for each AMPAC domain and compared with the established measures. Additionally, score distributions were analyzed by injury severity (mild vs moderate/severe). Functional outcome measures included AM-PAC (Basic Mobility (BM), Daily Activities (DA), and Applied Cognitive (AC) domains), Neuropsychological Assessment Battery (NAB), Texas Functional Living Scale (TFLS), Functional Independence Measure (FIM), Participation Assessment with Recombined Tools-Objective (PART-O), and Mayo-Portland Adaptability Inventory (MPAI-4: self-awareness).

Results:

Results: AMPAC was sensitive to changes throughout the care continuum from acute inpatient rehabilitation to 1-year post-injury, demonstrating medium effect sizes across all three functional domains. In the acute rehabilitation setting, a strong correlation was observed between FIM and AMPAC scores. Patient-reported self-rated long-term improvement scores revealed significant improvements in the AMPAC BM and DA domains at both 6 months and 1 year (p < 0.001). No significant changes were observed between 6 months and 1 year in AC domain indicating increased awareness of deficits.

For the outpatient cohort, AMPAC reported more significant effect sizes and MDC compared to other clinical measures. MDC thresholds demonstrated significant improvements within moderate/severe TBI (p < 0.05), with predictably smaller gains in the mild TBI population (p < 0.05), underscoring the clinical relevance of these findings. The paired t-tests revealed significant improvements in all domains in mild TBI patients (p < 0.05).

Conclusions:

Conclusions: These results demonstrate that the AM-PAC is a valid, reliable and sensitive measure responsive to longitudinal functional changes in the TBI population. This analysis emphasizes AM-PAC’s strengths in evaluating treatment outcomes across rehabilitation settings, injury severity, and the continuum of care.

Author(s) Disclosures: There are no conflicts of interest.