An international group of researchers* have agreed upon recommendations to revise the criteria for postmortem diagnosis of Alzheimer’s disease (AD). The meeting, convened in November 13-14, 1996, at the National Institutes of Health in Bethesda, was prompted by concerns that the present criteria, published in 1985, needed to be updated in light of advances over the past decade in the understanding of the disease.
The panel agreed to several general principles and specific recommendations regarding the diagnosis of AD. These include:
- Recognizing that, clinically and pathologically, AD is a heterogeneous disorder, and that postmortem examination alone can only yield statements of the probability of an Alzheimer's diagnosis.
- Considering as abnormal the presence any AD changes in the postmortem brain, such as diffuse or neuritic amyloid plaques and neurofibrillary tnagles. Any such changes should be considered pathological even in instances where they appear to be incidental.
- Judging a higher probability of an Alzheimer's diagnosis with increased frequency of BOTH neuritic plaques (using the scoring system currently used by CERAD, the Consortium to Establish a Registry for Alzheimer’s Disease) and neurofibrillary tangles in specified brain regions (using the staging system devised by Braak and Braak.
The panel recommended that all lesions found in the brain should be noted at autopsy and that all diagnoses present in any one patient- for example, vascular lesions and Lewy bodies-should be noted along with Alzheimer's lesions.
To improve upon the recommended criteria, the panel also called for further research aimed at a number of goals, including: to validate and refine the diagnostic procedures; to establish whether the variations observed in AD reflect genetic and gender factors; to determine the effects of age on the clinical and pathological criteria for the diagnosis of AD; to investigate the basis of milder, non-AD cognitive impairment and contrast this with both AD and normal aging; to develop and standardize iimproved diagnostic methods, reagents and quantitative techniques for postmortem diagnosis.
The Washington meeting was co-sponsored by the National Institute on Aging and the Alzheimer’s Association Ronald and Nancy Reagan Research Institute. The panel’s full recomendations, along with a complete set of position papers submitted by panel members, will be published in a future issue of the journal Neurobiology of Aging.
* The Working Group participants included: M. Ball, H. Braak, P. Coleman, D. Dickson, C. Duyckaerts, P. Gambetti, L. Hansen, B. Hyman, K. Jellinger, W. Markesbery, D. Perl, J. Powers, J. Price, J.Q. Trojanowski, H. Wisniewski. C. Phelps and Z. Khachaturian represented the NIA and the Reagan Institute, respectively. The meeting was chaired by J. Trojanwoski, and Drs. Hyman and Trojanowski co-chaired and led the concluding deliberations to formulate the consensus criteria.—June Kinoshita
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