Screening by telephone in the Alzheimer's disease anti-inflammatory prevention trial

Abstract

Compared with in-person assessment methods, telephone screening for dementia and other cognitive syndromes may improve efficiency of large population studies or prevention trials. We used data from the Alzheimer's Disease Anti-Inflammatory Prevention Trial to compare performance of a four-test Telephone Assessment Battery (TAB) that included the Telephone Interview for Cognitive Status (TICS) to that of a traditional in-person Cognitive Assessment Battery. Among 1,548 elderly participants with valid telephone and in-person screening results obtained within 90 days of each other, 225 persons were referred for a full cognitive diagnostic evaluation that was completed within six months of screening. Drawing on results from this panel of 225 individuals, we used the Capture-Recapture method to estimate population numbers of cognitively impaired participants. The latter estimates enabled us to compare the performance characteristics of the two screening batteries at specified cut-offs for detection of dementia and milder forms of impairment. Although our results provide relatively imprecise estimates of the performance characteristics of the two batteries, a comparison of their relative performance suggests that, at selected cut-off points, the TAB produces results broadly comparable to in-person screening and may be slightly more sensitive in detecting mild impairment. TAB performance characteristics also appeared slightly better than those of the TICS alone. Given its benefits in time and cost when screening for cognitive disorders, telephone screening should be considered for large samples.

Figure 1

Data selection flow-chart. White boxes depict each stage of data selection and the number of participants who met each respective selection criteria; black boxes show the number of participants excluded at each stage.

Figure 2

Number of participants assigned to each diagnostic group. The Venn diagrams depict the number of subjects whose DE was triggered by the CAB only (black), TAB only (light gray), or both (dark gray). Within diagnostic categories, the size of each circle is proportionate to the size of the corresponding circle, but circle sizes are not proportionate across diagnostic groups.