Article

OBJECTIVES: To build an item response theory-based computer adaptive test (CAT)
for balance from 3 traditional, fixed-form balance measures: Berg Balance Scale
(BBS), Performance-Oriented Mobility Assessment (POMA), and dynamic gait index
(DGI); and to examine whether the CAT's psychometric performance exceeded that of
individual measures. DESIGN: Secondary analysis combining 2 existing datasets.
SETTING: Community based. PARTICIPANTS: Community-dwelling older adults (N=187)
who were aged >/=65 years (mean age, 75.2+/-6.8y, 69% women). INTERVENTIONS: Not
applicable. MAIN OUTCOME MEASURES: The BBS, POMA, and DGI items were compiled
into an initial 38-item bank. The Rasch partial credit model was used for final
item bank calibration. CAT simulations were conducted to identify the ideal CAT.
CAT score accuracy, reliability, floor and ceiling effects, and validity were
examined. Floor and ceiling effects and validity of the CAT and individual
measures were compared. RESULTS: A 23-item bank met model expectations. A 10-item
CAT was selected, showing a very strong association with full item bank scores
(r=.97) and good overall reliability (.78). Reliability was better in low- to
midbalance ranges as a result of better item targeting to balance ability when
compared with the highest balance ranges. No floor effect was noted. The CAT
ceiling effect (11.2%) was significantly lower than the POMA (40.1%) and DGI
(40.3%) ceiling effects (P<.001 per comparison). The CAT outperformed individual
measures, being the only test to discriminate between fallers and nonfallers
(P=.007), and being the strongest predictor of self-reported function.
CONCLUSIONS: The balance CAT showed excellent accuracy, good overall reliability,
and excellent validity compared with individual measures, being the only measure
to discriminate between fallers and nonfallers. Prospective examination,
particularly in low-functioning older adults and clinical populations with
balance deficits, is recommended. Development of an improved CAT based on an
expanded item bank containing higher difficulty items is also recommended.
CI - Copyright (c) 2014 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS