NEUROPATHOLOGIC DIAGNOSIS OF ALZHEIMER-DISEASE - CONSENSUS BETWEEN PRACTICING NEUROPATHOLOGISTS

In an attempt to gather information on procedures, criteria, and possi ble difficulties, we have sent a detailed questionnaire on the postmor tem diagnosis of Alzheimer disease (AD) to 169 neuropathologists in th e German-speaking countries-Germany Austria, and Switzerland. Of a tot al of 104 responses, 65 completed questionnaires were evaluated statis tically. Fifty-nine percent of all respondents consider the neuropatho logic diagnosis of AD a problem. Although 38% consider themselves able to establish the diagnosis without knowledge of clinical data, 29% do not believe this is possible. Thirty-eight percent opine that the pre sence of neurofibrillary tangles is not a prerequisite for a positive diagnosis, and 3% believe that examination of the hippocampal formatio n is unnecessary. For 6% of the respondents, neither a, silver stain n or thioflavin S is necessary. Ninety-seven percent believe that the av ailability of explicit diagnostic criteria would be helpful; by contra st, only 43% have exact knowledge of the National institute of Aging c riteria, and only 29% have exact knowledge of the Consortium to Establ ish a Registry for Alzheimer's Disease (CERAD) criteria. Only every fo urth neuropathologist uses these criteria regularly and the validity o f current diagnostic criteria is challenged by a considerable number o f respondents. Many pathologists consider the quantification of plaque s and tangles problematic, are confused by a lacking correlation of th e pathology with the clinical picture, and believe that the gray zone between normal aging and full-fledged AD represents a major diagnostic problem. Our survey shows that there currently is no consensus on dia gnostic procedures and criteria used in practice. This stresses the ne ed for precise diagnostic guidelines and continuing information of act ively practicing neuropathologists to achieve higher interlaboratory r eliability of the diagnosis of AD.