Prevalence and pathology of dementia with Lewy bodies in the oldest old: a comparison with other dementing disorders.

BACKGROUND

While the prevalence of Alzheimer disease (AD) increases with age, little is known about the frequency of dementia with Lewy bodies (DLB) in the oldest old. A retrospective hospital-based study compared the relative prevalence of DLB among very old individuals.

METHODS

1,100 consecutive autopsy cases of demented patients aged over 70 years (mean age: 83.9 ± 5.4 years) were examined using standardized neuropathological methods and current diagnostic consensus criteria.

RESULTS

Evaluation of three age groups (8th-10th decade) showed a significant increase in the relative prevalence of AD with cerebrovascular lesions including mixed dementia, while AD with Lewy body (LB) pathology showed a mild but insignificant age-related increase. Both 'pure' AD and vascular dementia showed a mild but insignificant decline, while DLB (without severe AD pathology) decreased progressively. While the severity of Lewy pathology in DLB slightly decreased with age, concomitant Alzheimer-like pathology increased progressively.

CONCLUSION

Whether DLB in the oldest old represents a distinct group is a matter of discussion, but the relative prevalence of AD with LB in our sample remained fairly stable.