Development of a Screening Algorithm for Alzheimer's Disease Using Categorical Fluency and Confrontational Naming Abilities

OBJECTIVE: Declines in naming ability and semantic memory are well-known features of early Alzheimer's disease (AD). We developed a new screening algorithm for AD using two brief language tests : the Categorical Fluency Test (CFT) and 15-item Boston Naming Test (BNT15). METHODS: We administered the CFT, BNT15, and Mini-Mental State Examination (MMSE) to 150 AD patients with a Clinical Dementia Rating of 0.5 or 1 and to their age- and gender-matched cognitively normal controls. We developed a composite score for screening AD (LANGuage Composite score, LANG-C) that comprised demographic characteristics, BNT15 subindices, and CFT subindices. We compared the diagnostic accuracies of the LANG-C and MMSE using receiver operating curve analysis. RESULTS: The LANG-C was calculated using the logit of test scores weighted by their coefficients from forward stepwise logistic regression models : logit (case)=12.608−0.107×age+1.111×gender+0.089×education−0.314×HS(1st)−0.362×HS(2nd)+0.455×perseveration+1.329×HFCR(2nd)−0.489×MFCR(1st)−0.565×LFCR(3rd). The area under the curve of the LANG-C for diagnosing AD was good (0.894, 95% confidence interval=0.853–0.926 ; sensitivity=0.787, specificity=0.840), although it was smaller than that of the MMSE. CONCLUSION: The LANG-C, which is easy to automate using PC or smart devices and to deliver widely via internet, can be a good alternative for screening AD to MMSE.

Parallel Short Forms for the Korean-Boston Naming Test (K-BNT)

BACKGROUND: The Korean-Boston Naming Test (K-BNT) is a popular measure of the confrontational naming ability. It is particularly sensitive to the early cognitive changes in Alzheimer's disease (AD) and Vascular dementia (VaD). The current study was conducted to develop parallel short forms for the K-BNT used in repeated assessments as well as in situations where the administration of the complete K-BNT is not practical. METHODS: Four 15-item short forms were newly constructed based on the item difficulties of the K-BNT measured from 565 normal elderly aged over 55. The K-BNT was administered to 130 dementia patients (75 AD, 55 VaD) and 130 healthy community-dwelling elderly whose age, sex, and education level were matched with the dementia patients. Scores for the short forms were derived by dividing up the items of the K-BNT. RESULTS: On each short form, normal elderly performed better than dementia patients, and scores on each could be extrapolated to a complete 60-item K-BNT score. Significant correlations were found between short forms and the K-BNT. To compare the probabilities of correctly identifying dementia, the areas under Receiver Operating Characteristic (ROC) curves of each form and the K-BNT were compared. It was found that all the short forms were as efficient as the 60-item K-BNT in identifying dementia. CONCLUSIONS: These results confirm that the four 15-item short forms developed in the current study are parallel and valid as the short forms of the K-BNT.