Dementia screening: can a second administration reduce the number of false positives?

Early diagnosis of dementia is important for medical treatment and quality-of-life interventions. The authors examine whether administering a second cognitive screening after a poor initial score can improve the accuracy of diagnosis. Of particular interest is reducing false positives that may generate an unnecessary referral for a dementia work-up.

A group of 389 Japanese men from the Honolulu-Asia Aging Study were administered the Cognitive Assessment Screening Instrument (CASI) twice within a 2-month period. A small sample received a follow-up CASI 3 years later.

Administration of a second CASI reduced the false-positive rate by 16.1% in the total sample and 20.2% in those suspected of having mild dementia. The negative predictive value for the second administration was 80% for the entire sample and 82.6% for those suspected of having mild dementia.

Administration of a second cognitive screening in patients initially scoring in the dementia range can significantly reduce the number of false positives for dementia. This technique may be useful to managed-care companies who aim to reduce unnecessary costs in medical care.