Simulation study of activities of daily living functions using online computerized adaptive testing

BACKGROUND: Computer adaptive testing (CAT) of the activities of daily living (ADL) functions is required (i) to reveal the advantages of using an efficient and accurate estimation method, (ii) to determine the cutpoint for classifying ADL strata in patients with stroke, and (iii) to evaluate the feasibility of online CAT used in clinical settings for smartphones. METHODS: Normally standardized distributions of ADL measurements were simulated using item parameters from published papers. We retrieved item parameters of the combined Barthel Index and Frenchay Activities Index from the literature (the 23-item comprehensive ADL [CADL] and 34-item ADL scales) and simulated three 1000-person measures from a normal standard CAT distribution: [i] CADL (CADL-CAT), [ii] ADL (ADL-CAT), and [iii] NAT (Non-Adaptive Testing). The cutpoints of ADL person strata were determined using a norm-reference method. Maximum a posteriori estimation, expected a posteriori estimation, and maximum likelihood estimation (MAP) were used to compare the Pearson correlation coefficients and different number ratios of paired measures yielded by CAT and NAT. The number of items and the cutpoints for the scale were separately determined. RESULTS: We found that (i) correlation coefficients for the three CAT-estimated measures were 0.77 (CADL), 0.93 (Male ADL), and 0.93 (Female ADL) compared with their NAT counterparts. Different number ratios of person-paired measures between CAT and NAT for the three scales were all less than 5 %, indicating no difference exists between CAT and NAT. However, CAT might be 66 % more efficient than NAT. (ii) The estimated cutpoints of T scores (i.e., with a mean of 50 and a standard deviation of 10) were 45, 55, and 65 (e.g., separating person ADL function to four strata with not active, fairly active, active, and very active). (iii) An available-for-download online ADL-CAT APP for clinical practice was demonstrated. CONCLUSIONS: An online ADL-CAT APP using the MAP method was created and used on smartphones to classify ADL strata in patients with stroke. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12911-016-0370-8) contains supplementary material, which is available to authorized users.