Impairment In Dementia With Lewy Bodies Research Articles

Cognitive loss in dementia with Lewy bodies and Alzheimer disease.

Dementia with Lewy bodies (DLB) is emerging as a common cause of degenerative dementia. Some preliminary evidence exists that the pattern of cognitive impairment in DLB is different from that in Alzheimer disease (AD). To delineate features of cognitive impairment of DLB on standardized neuropsychological tests. We performed neuropsychological assessments of 26 patients with probable DLB (based on criteria of the consortium on DLB international workshop) and of 52 patients with probable AD (based on criteria of the National Institute of Neurological and Communicative Disorders and Stroke [now the National Institute of Neurological Disorders and Stroke])-Alzheimer's Disease and Related Disorders Association) who were matched to the patients with DLB 2:1 by age, sex, education, and Mini-Mental State Examination score. Compared with the group with probable AD, the group with probable DLB scored significantly lower on the picture arrangement, block design, object assembly, and digit symbol substitution subtests of the Wechsler Adult Intelligence Scale-Revised and on the Raven Colored Progressive Matrices test and significantly higher on the Mini-Mental State Examination locational orientation subtest and the Alzheimer's Disease Assessment Scale word recall subtest. A discriminant analysis revealed that the word recall score on the Alzheimer's Disease Assessment Scale and the block design score on the Wechsler Adult Intelligence Scale-Revised were the best discriminant factors. The disproportionately severe visuoperceptual, visuoconstructive, and visuospatial dysfunction and the disproportionately mild memory impairment in DLB compared with AD, which likely reflect the distribution of the pathologic changes in DLB, can help to differentiate DLB from AD.

Dementia with Lewy bodies versus pure Alzheimer disease: differences in cognition, neuropathology, cholinergic dysfunction, and synapse density.

Dementia with Lewy bodies (DLB) is the second leading cause of cognitive impairment among the elderly. While it is usually accompanied by the neocortical neuritic plaques (NP) and entorhinal neurofibrillary tangles (NFT) characteristic of Alzheimer disease (AD), and so can be construed as a Lewy body variant of AD (LBV), it also occurs in pure form as diffuse Lewy body disease (DLBD). We assessed cognitive status in 17 DLB patients (12 with LBV and 5 with DLBD) and compared the results with 12 AD subjects and 5 controls. We then sought to determine which neuropathologic abnormalities correlated with cognitive impairment. Among DLB cases, neocortical Lewy body (LB) counts, modified Braak stages of NFT burden in the entorhinal cortex, neocortical NP counts, and loss of choline acetyltransferase (ChAT) activity all correlated with dementia severity. Unlike AD, neocortical NFT and anti-synaptophysin reactivity were uncorrelated with DLB dementia. Despite comparable LB counts and ChAT losses, the DLBD were significantly less demented than the LBV patients. We conclude that neocortical LB and ChAT depletion contribute to cognitive impairment in DLB and that concomitant AD pathology in LBV, represented by higher Braak stages and NP, promotes increased dementia severity compared with that encountered in DLBD.