Screening for dementia: Comparison of three commonly used instruments

The sensitivity and specificity of three cognitive screening measures - the Mini-Mental State Exam (MMSE), Mattis Dementia Rating Scale (MDRS), and Neurobehavioral Cognitive Status Examination (NCSE) - were compared in a cohort of subjects with dementia as well as normal elderly individuals. Twenty-two patients met criteria for probable Alzheimer's disease (AD), 19 for vascular dementia (VaD), and 12 were normal control subjects. The use of standard cutpoints resulted in poor to good classification accuracy for the three measures, but measurable improvement in sensitivity was obtained by adjusting the cutpoints for each measure. Discriminatory power was maximized with an MMSE cutpoint of less than or equal to 26, an MDRS cutpoint of less than or equal to 134, and requiring one or more NCSE subtests to be in the impaired range. Use of age and education adjusted norms resulted in good to excellent classification accuracy for the MMSE and MDRS. The NCSE subtest score pattern failed to differentiate between AD and VaD.