Clinical Health Updates

Brief evaluation aids diagnosis of dementia

Clinical Question:
Can simple interviews of caregivers coupled with recall testing aid the diagnosis of dementia?

Bottom Line:
The combination of an 8-item test administered to caregivers coupled with a 10-word recall list is very good at ruling out dementia and is relatively good at diagnosing it in elderly patients with cognitive, behavioral, and mood disorders.

Reference:
Galvin JE, Roe CM, Morris JC. The evaluation of cognitive impairment in older adults: combining brief informant and performance Measures. Arch Neurol 2007;64:718-724.

Study Design:
Cross-sectional

Synopsis:
To combine the AD8, a brief informant interview, with performance measures to develop a brief screening tool to improve detection of cognitive impairment and dementia in general practice. The AD8 was administered to informants. Clinicians conducted independent patient evaluations and administered the Clinical Dementia Rating Scale and a 30-minute neuropsychological battery. Logistic regression was used to determine the best combination of brief tests to correctly classify patients as having no dementia, uncertain dementia, or dementia. The area under the receiver operator characteristic curve (AUC) evaluated the discriminative ability of the combined tests. Patients (n = 255) were consecutive referrals to a dementia clinic. Patients had a mean +/- SD age of 73.3 +/- 11.3 years, with 13.7 +/- 3.0 (mean +/- SD) years of education. The sample was 56% women; 77% of patients were white. Main Outcome Measure Dementia classification. RESULTS: A model combining the AD8 interview (odds ratio, 1.91; 95% confidence interval, 1.6-2.3) and the Consortium to Establish a Registry for Alzheimer Disease 10-item Word List Recall (odds ratio, 1.43; 95% confidence interval, 1.2-1.7) predicted dementia with 91.5% correct classification (AUC = 0.968; 95% confidence interval, 0.93-0.99). A cutoff of 2 or greater on the AD8 and less than 5 items remembered on the Word List Recall was sensitive (94%) and specific (82%). For cognitive impairments not meeting dementia criteria, combining AD8 (odds ratio, 2.31; 95% confidence interval, 1.3-4.0) and Word List Recall (odds ratio, 1.42; 95% confidence interval, 1.1-1.8) was most predictive (AUC = 0.91; 95% confidence interval, 0.8-1.0). Using the same cutoffs as those used for dementia gave the best combination of sensitivity (85%) and specificity (84%).

*A copy of the AD8 table with scoring rules may be found at

http://alzheimer.wustl.edu/About_Us/PDFs/AD8form2005.pdf.