Recent neuropathologic autopsy studies found that 15 to 25% of elderly demented patients have Lewy bodies (LB) in their brainstem and cortex, and in hospital series this may constitute the most common pathologic subgroup after pure Alzheimer's disease (AD). The Consortium on Dementia with Lewy bodies met to establish consensus guidelines for the clinical diagnosis of dementia with Lewy bodies (DLB) and to establish a common framework for the assessment and characterization of pathologic lesions at autopsy. The importance of accurate antemortem diagnosis of DLB includes a characteristic and often rapidly progressive clinical syndrome, a need for particular caution with neuroleptic medication, and the possibility that DLB patients may be particularly responsive to cholinesterase inhibitors. We identified progressive disabling mental impairment progressing to dementia as the central feature of DLB. Attentional impairments and disproportionate problem solving and visuospatial difficulties are often early and prominent. Fluctuation in cognitive function, persistent well-formed visual hallucinations, and spontaneous motor features of parkinsonism are core features with diagnostic significance in discriminating DLB from AD and other dementias. Appropriate clinical methods for eliciting these key symptoms are described. Brainstem or cortical LB are the only features considered essential for a pathologic diagnosis of DLB, although Lewy-related neurites, Alzheimer pathology, and spongiform change may also be seen. We identified optimal staining methods for each of these and devised a protocol for the evaluation of cortical LB frequency based on a brain sampling procedure consistent with CERAD. This allows cases to be classified into brainstem predominant, limbic (transitional), and neocortical subtypes, using a simple scoring system based on the relative distribution of semiquantitative LB counts. Alzheimer pathology is also frequently present in DLB, usually as diffuse or neuritic plaques, neocortical neurofibrillary tangles being much less common. The precise nosological relationship between DLB and AD remains uncertain, as does that between DLB and patients with Parkinson's disease who subsequently develop neuropsychiatric features. Finally, we recommend procedures for the selective sampling and storage of frozen tissue for a variety of neurochemical assays, which together with developments in molecular genetics, should assist future refinements of diagnosis and classification.

The authors report a patient with Alzheimer disease (AD) without encephalitis who was immunized with AN-1792 (an adjuvanted formulation of Abeta-42). There were no amyloid plaques in the frontal cortex and abundant Abeta-immunoreactive macrophages, but tangles and amyloid angiopathy were present. The white matter appeared normal and minimal lymphocytic infiltration in the leptomeninges was observed. This case illustrates the effects of an Abeta-based immunization on AD pathogenesis in the absence of overt meningoencephalitis and leukoencephalopathy.

A dinucleotide repeat polymorphism in a tau intron was identified and used in a case-control study to analyze the genetic association of tau with several neurodegenerative diseases with tau pathology. Subjects with the homozygous tau AO alleles were excessively represented in the progressive supranuclear palsy (PSP) group, compared with the age-matched healthy control group. Consequently, this allele is more frequently found in PSP than in a group of healthy subjects. This trend was not found in Alzheimer's disease or parkinsonism-dementia complex of Guam, both of which are accompanied by major tau pathology. The result suggests a possible involvement of tau in the pathogenesis of PSP.

This report summarizes the neuropathologic findings in the first 106 autopsies of CERAD (Consortium to Establish a Registry for Alzheimer's Disease) dementia patients diagnosed clinically as having Alzheimer's disease (AD). In 92 (87%) of the 106 cases, neuropathologists confirmed Alzheimer's disease (AD) as the primary dementing illness. Coexistent Parkinson's disease (PD) changes were present in 19 (21%) and vascular lesions of varying nature and size in 26 (28%) of these 92 AD cases. The 14 cases in which AD was not interpreted as the primary dementing illness can be divided into four major subgroups based on their neuropathology findings: PD and related pathology (n = 5), hippocampal sclerosis (n = 3), miscellaneous neurodegenerative and other disorders (n = 3), and no significant changes (n = 3). Despite the relatively high level of clinical diagnostic accuracy, further refinement of assessment batteries may facilitate distinction of non-AD dementias from AD.

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