Base rates of errors made by healthy older adults on the clock drawing and verbal fluency tests

Authors: Shayne S‐H Lin, Ashita S. Gurnani, Brandon E. Gavett

Published: 2020-12-07

Abstract

AbstractBackgroundIn the realm of neuropsychological assessment, the Boston Process Approach is a method to analyze the errors made along the process that individuals take to the solution. Considering the clinical utility of base rates in estimating the probability of an individual being cognitively normal or impaired, the present study aimed at reporting the base rates of errors on the verbal fluency test and the Clock Drawing Test.MethodData of 88 cognitively normal elder participants performing the Animal Fluency, the Letter Fluency, the Clock Command, and the Clock Copy were pulled from a larger data set and coded based on the Boston Process Approach.ResultAs shown on table 1, it was found that, on verbal fluency test, repetition error was frequently made among cognitively healthy older adults while perseverative error and set‐loss error was relatively rare. On the Clock Drawing test, on the other hand, as shown on table 2, conceptual error was quite common whereas stimulus‐bound error was quite rare.ConclusionAs illustrated in Gavett (2015), base rate data regarding errors made on neuropsychological tests from cognitively healthy older adults are crucial to construct and estimate the probability of an individual being cognitively impaired when number of errors made on a test is known. Therefore, the current data provides valuable information for the purpose of dementia diagnosis.