Diagnosis of dementia. Methods for interpretation of scores of 5 neuropsychological tests
N. Meiran, D. T. Stuss, D. A. Guzman, G. Lafleche and J. Willmer
Rotman Research Institute of Baycrest Centre, Ontario.
OBJECTIVE: To provide methods to interpret and compare different
neurobehavioral screening tests for the diagnosis of dementia. DESIGN: Five
mental-status neuropsychological tools for dementia screening were
administered to patients in a memory disorder clinic. These included the
Mini-Mental State Examination, the Dementia Rating Scale, the 6-item
derivative of the Orientation-memory-Concentration Test, a short Mental
Status Questionnaire, and a composite tool we labeled the Ottawa Mental
Status Examination, which assessed orientation, memory, attention,
language, and visual-constructive functioning. RESULTS: To obtain z and
percentile scores, norms are for the different tests, computed separately
for patients with dementia of the Alzheimer type, vascular dementia, or no
dementia. Another set of norms is reported in which a test score is
translated directly into the posttest probability of dementia. Translation
formulas are given to allow the estimation of the score on one test from
the result on another test. CONCLUSION: The interpretation of tests used to
diagnose dementia must be based on an understanding of the meaning of an
individual score, which is based on the question asked and the population
to which the patient is referenced.