Performance of an item response theory-based computer adaptive test in identifying functional decline

Arch Phys Med Rehabil. 2012 Jul;93(7):1153-60. doi: 10.1016/j.apmr.2012.02.008. Epub 2012 Feb 25.


Objective: To achieve a low respondent burden and increase the responsiveness of functional measurement by using an item response theory-based computer adaptive test (CAT), the Activity Measure for Post-Acute Care (AM-PAC) CAT.

Design: Two-year prospective cohort study.

Setting: Telephonic assessments from a quaternary medical center.

Participants: Patients (N=311) with late-stage lung cancer (LC).

Interventions: Monthly assessments for up to 2 years. Disease progression was determined via record abstraction. Anchor-based responsiveness techniques were used to compare AM-PAC-CAT score changes between global rating of change (GRC) question response levels, as well as between intervals when adverse clinical events or symptom worsening did and did not occur. Distribution-based responsiveness assessments included calculation of the standardized effect size (SES) and standardized response mean (SRM).

Main outcome measures: AM-PAC-CAT, symptom numerical rating scales, and a GRC.

Results: Administration time averaged 112 seconds over 2543 interviews. AM-PAC-CAT score changes became more positive as GRC responses reflected more improved states: a lot worse (-11.62), a little worse (-1.92), the same (-.10), a little better (1.01), and a lot better (2.82). Score changes were negative when associated with adverse clinical events. The SES and SRM for score differences between 1 to 2 and 9 to 10 months prior to death were -.87 and -1.13, respectively. The minimally important difference estimate was defined by the mean CAT session SE at 2.0.

Conclusions: The AM-PAC-CAT imposes a low, <2-minute, respondent burden, and distribution- and anchor-based methods suggest that is moderately responsive in patients with late-stage LC.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Activities of Daily Living*
  • Aged
  • Aged, 80 and over
  • Carcinoma, Non-Small-Cell Lung / diagnosis
  • Carcinoma, Non-Small-Cell Lung / mortality
  • Carcinoma, Non-Small-Cell Lung / therapy*
  • Cohort Studies
  • Continuity of Patient Care*
  • Disability Evaluation
  • Disease Progression
  • Disease-Free Survival
  • Female
  • Follow-Up Studies
  • Humans
  • Linear Models
  • Lung Neoplasms / diagnosis
  • Lung Neoplasms / mortality
  • Lung Neoplasms / therapy*
  • Male
  • Medical Records Systems, Computerized / statistics & numerical data*
  • Middle Aged
  • Monitoring, Physiologic / methods*
  • Multivariate Analysis
  • Neoplasm Invasiveness / pathology
  • Neoplasm Staging
  • Odds Ratio
  • Prospective Studies
  • Risk Assessment
  • Sickness Impact Profile
  • Survival Rate
  • Time Factors