Comparison of Lewy body variant of Alzheimer's disease with pure Alzheimer's disease: Consortium to Establish a Registry for Alzheimer's Disease, Part XIX.

OBJECTIVE

To compare the clinical, neuropsychological, and neuropathologic findings in patients with AD alone with those in patients with the Lewy body variant of AD (LBV).

BACKGROUND

Prior studies indicate that patients with LBV not only have distinct clinical and neuropsychological differences from those with AD alone, but have a poorer prognosis with shorter survival time.

METHODS

The authors evaluated 74 patients with autopsy-confirmed AD alone and 27 patients with LBV, and compared demographic characteristics and clinical, neuropsychological, and neuropathologic findings.

RESULTS

The two groups of patients were equivalent with respect to age at time of entry into the study, years of education, and sex. Two or more extrapyramidal clinical manifestations were found in 44% of patients with LBV, compared with 16% of patients with AD alone (p = 0.02). Duration of survival after entry into the study was similar in both groups, with a mean survival of 3.6 (+/-2.1) years for AD alone versus 3.8 (+/-1.9) years for LBV. Of the various neuropsychological tests administered at the last Consortium to Establish a Registry for Alzheimer's Disease evaluation, only delayed recall of a learned word list was significantly different in the two groups, with 32% of patients with LBV versus 15% of patients with AD alone recalling any items (p = 0.04). Neuropathologic findings confirmed those of previous studies and showed that neurofibrillary tangles were significantly less frequent in the neocortex of patients with LBV than in those with AD alone.

CONCLUSION

Compared with patients with AD alone, those with LBV had a greater frequency of extrapyramidal manifestations, somewhat better recall on a selected memory task at their final evaluation, and a significantly lower frequency of neocortical neurofibrillary tangles at autopsy. There were no differences between the two groups, however, in survival time from entry into the study.