The Minimum Clinically Important Difference in the Repeatable Battery for the Assessment of Neuropsychological Status

Abstract

Objective: There is no established minimum clinically important difference (MCID) for the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) index and total scale scores. This study aimed to estimate the MCID for the RBANS index scores and total scale score. Method: Participants included 1,856 ethnic Chinese, older adults. Distribution- and anchor-based methods were used to estimate values for the MCID. Distribution-based estimates were calculated as the standard error of measurement (SEM) and .5 standard deviations (SD). For anchor-based estimates, we compared RBANS scores between the clinical dementia rating (CDR) scale no dementia and very mild dementia groups and between the clinical assessment of dementia (CAD) cognitively normal and mild cognitive impairment groups using regression models adjusting for demographic characteristics. Results: Estimates from the CDR anchor were 7.79, 8.63, 10.74, 9.74, 5.61, and 3.77 for the total scale score, language, immediate memory, delayed memory, visuospatial/constructional, and the attention index, respectively. Estimates from the distribution-based methods were similar to the estimates based on the CDR, except for the language and attention indexes. Estimates from the CAD anchor were larger. Conclusions: We estimated the MCID for the total scale score, language, immediate memory, delayed memory, visuospatial/constructional, and attention indexes of the RBANS as 8, 9, 10, 10, 6, and 4 points, respectively. These estimates are best suited to discriminate between patient groups, for example, in a clinical trial setting. Further research is needed using longitudinal data to assess their applicability to assess within patient differences.