THE PREDEMENTIA ALZHEIMER'S DISEASE SCALE (PAS)


Introduction

The Predementia Alzheimer's disease Scale (PAS) aims to identify subjects with mild cognitive impairments (or cognitive impairment no dementia) who are in the preclinical stage of Alzheimer's disease. The PAS consist of six items: age, MMSE score, functional impairment, cognitive test performance, apolipoprotein E (apoE) genotype, and medial temporal lobe (MTL) atrophy. The selection of the variables of the PAS was based on a review and meta-analysis of 21 prospective studies of subjects with cognitive impairment no dementia. Each variable can be scored on a 3 or 4-point scale. The sum score determines the risk for AD. The cut off scores for the PAS items were determined a priori on the basis of the literature. Instructions how to use the PAS are listed below. The validation of the PAS has been done in subjects with mild cognitive impairments from the Maastricht Memory Clinic. In this validation study it was shown that a PAS score >= 6 was associated with a high risk for subsequent AD, a score of 5 with a borderline risk and a score <= 4 with a low risk for AD. Stepwise scoring of the PAS could reduce the number of subjects who need to undergo elaborate or expensive diagnostic procedures (such as cognitive testing, MRI scanning or apoE genotyping) for predicting outcome.

These data have now been published as:
Diagnostic accuracy of the Predementia AD Scale (PAS) in cognitively mildly impaired subjects (pdf: Visser et al. Journal of Neurology 2002, 249: 312-319).
Validation studies in other settings are underway.
The PAS score was shown to correlate with the level of phospho-tau and b-amyloid 1-42 in cerebrospinal fluid suggesting that the PAS indeed reflects AD pathology (see pdf of the poster) presented at the 9th International Conference on Alzheimer's Disease and associated disorders in Philadelphia, 19-23 July 2004).

The PAS has been developed at the Department of Psychiatry and Neuropsychology, Institute of Brain and Behavior, University of Maastricht, The Netherlands. The PAS and instructions how to use the PAS are on this site for free. If you want to use the PAS for research or clinical purposes please subscribe in order to receive by e-mail the PAS-news bulletin which keeps you informed about the latest developments, updates, and validation studies of the PAS. We would also greatly appreciate to hear your experiences with the PAS and any suggestions for improvements. If you want to set-up a validation study, please do not hesitate to contact us. For all information or comments please contact us by e-mail or you can send a letter to: PJ Visser, Department of Psychiatry, Academisch Ziekenhuis Maastricht, PO Box 5800, NL-6200 AZ Maaastricht, The Netherlands.

The copyright of the Predementia Alzheimer's disease Scale (PAS) and text on this site belongs to the department of Psychiatry and Neuropsychology, Institute of Brain and Behavior, University of Maastricht, The Netherlands © 2000.



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