TY - JOUR
T1 - Calibration of the activity inventory itembank
T2 - A patient-reported outcome measurement instrument for low vision rehabilitation
AU - Gobeille, Micaela
AU - Bradley, Chris
AU - Goldstein, Judith E.
AU - Massof, Robert
N1 - Funding Information:
Supported by grants from the National Eye Institute, National Institutes of Health (R44EY028077, R01EY026617, R01EY022322, R34EY018696, R01EY012045, U01EY015839, and T35EY007149).
Publisher Copyright:
© 2021 The Authors.
PY - 2021
Y1 - 2021
N2 - Purpose: To provide calibrated item measures and rating category thresholds for the Activity Inventory (AI), an adaptive visual function questionnaire, from difficulty ratings obtained from a large sample of new low vision patients at pre-rehabilitation baseline. Methods: Baseline AI (510 items) rating scale data from five previous low vision rehabilitation outcome studies (n = 3623) were combined, and the method of successive dichotomizations was used to estimate calibrated item measures and rating category thresholds. In fit statistics were analyzed to evaluate the fit of the data to the model. Factor analysis was applied to person measures estimated from different subsets of items (e.g., functional domains such as reading, mobility) to evaluate differential person functioning. Results: Estimated item measures were well targeted to the low vision patient population. The distribution of in fit statistics confirmed the validity of the estimated measures and the two-factor structure previously observed for the AI. Conclusions: Our calibrated item measures and rating category thresholds enable researchers to estimate changes in visual ability from low vision rehabilitation on the same scale, facilitating comparisons between studies. Translational Relevance: The work described in this paper provides calibrated item measures and rating category thresholds for a visual function questionnaire to measure patient-centered outcomes in low vision clinical research. The calibrated AI also can be used as a patient outcome measure and quality assurance tool in clinical practice.
AB - Purpose: To provide calibrated item measures and rating category thresholds for the Activity Inventory (AI), an adaptive visual function questionnaire, from difficulty ratings obtained from a large sample of new low vision patients at pre-rehabilitation baseline. Methods: Baseline AI (510 items) rating scale data from five previous low vision rehabilitation outcome studies (n = 3623) were combined, and the method of successive dichotomizations was used to estimate calibrated item measures and rating category thresholds. In fit statistics were analyzed to evaluate the fit of the data to the model. Factor analysis was applied to person measures estimated from different subsets of items (e.g., functional domains such as reading, mobility) to evaluate differential person functioning. Results: Estimated item measures were well targeted to the low vision patient population. The distribution of in fit statistics confirmed the validity of the estimated measures and the two-factor structure previously observed for the AI. Conclusions: Our calibrated item measures and rating category thresholds enable researchers to estimate changes in visual ability from low vision rehabilitation on the same scale, facilitating comparisons between studies. Translational Relevance: The work described in this paper provides calibrated item measures and rating category thresholds for a visual function questionnaire to measure patient-centered outcomes in low vision clinical research. The calibrated AI also can be used as a patient outcome measure and quality assurance tool in clinical practice.
KW - Activity Inventory
KW - Low vision
KW - Rasch analysis
KW - Visual function questionnaire
KW - Visual impairment
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U2 - 10.1167/tvst.10.6.12
DO - 10.1167/tvst.10.6.12
M3 - Article
C2 - 34111258
AN - SCOPUS:85106616783
SN - 2164-2591
VL - 10
JO - Translational Vision Science and Technology
JF - Translational Vision Science and Technology
IS - 6
M1 - 12
ER -