[Diagnostic norms of RAPID neuropsychological battery tests for subjects aged 60 to 89 years with Alzheimer's disease]

Abstract

Introduction: The aim of this study was to propose diagnostic norms for the rapid neuropsychological battery, in the detection of cognitive impairment due to Alzheimer's disease.

Population and methods: Three hundred and fifty-two control subjects (mean MMSE : 27.3 ± 2.5) and 676 patients with Alzheimer's disease (mean MMSE : 22.9 ± 2.6) at a mild stage (CDR = 1) were selected according to age (60-69, 70-79 and 80-89 years) and educational level (French primary Education Certificate or lower versus Certificate of Professional Aptitude or the School Leaving Certificate versus the Baccalaureate or higher). Age and education-adjusted cut-off scores were calculated using Receiver Operating Characteristic curves so as to determine the discriminative ability (sensitivity, specificity) of each test from the RAPID neuropsychological battery. Cut-off scores with a specificity set at least at 90% were also proposed.

Results: The Free and Cued Recall Test exhibited good sensitivity (from 87% to 100% for free recall and from 85% to 98% for total recall) and specificity (from 85% to 96% for free recall and from 86% to 100% for total recall). For the other tests, sensitivities and specificities were lower.

Conclusion: The use of these two types of cut-off scores should help the clinician in the diagnosis of Alzheimer's disease by limiting the risk of false positives and false negatives. The choice of the cut-off scores will depend on the patient's individual clinical context.