Table 3.

Primary Neuropathological Diagnoses for the 38 National Alzheimer's Disease Coordinating Center Subjects with Moderate or Frequent Neuritic Plaque Densities But Not Meeting Neuropathological Definition of Alzheimer Disease

Primary Neuropathological Findings	Number of subjects
Primary neuropathological diagnosis of AD despite low level of AD histopathology	9
Frontotemporal lobar degeneration	12
Lewy body disease	11
Hippocampal sclerosis	1
Progressive supranuclear palsy	1
AD pathology present but insufficient for diagnosis	2
“Extreme depopulation of substantia nigra”	1
Normal brain	1

Subjects had moderate or frequent CERAD neuritic plaque densities but did not meet neuropathological definition of Alzheimer Disease because of a Braak neurofibrillary stage less than III (based on majority read data).

AD, Alzheimer disease; CERAD, Consortium to Establish a Registry for Alzheimer's Disease; NACC, National Alzheimer's Coordinating Center, University of Washington, Seattle, WA.