Methods : A 20-year chart review of the Alzheimer’s Research Center Brain Bank identified neuropathologically diagnosed patients with Alzheimer’s Disease (AD). Clinical data was based on medical records and a standardized questionnaire answered by a family member. Neuropathologic diagnosis was established by a University of Minnesota neuropathologist.
Inclusion Criteria : Patients with onset of dementia symptoms at or before 65 years were categorized as EO-AD, and onset at 71 years or more were categorized as LO-AD.
Exclusion Criteria : Patients with onset of dementia symptoms between 66-70 years were excluded to minimize overlap. Incomplete charts or a clinical diagnosis of AD without neuropathologic evidence were also excluded.
Results : 422 of 532 identified AD cases met the inclusion criteria (137 EO-AD and 285 LO-AD). Among presenting symptoms noted, LO-AD had significantly more cognitive decline, while EO-AD presented with more combination of cognitive and behavioral change. Depression was more prominent in the EO-AD and olfactory dysfunction more prominent in LO-AD. No significant differences in family history of dementia, history of head trauma with loss of consciousness, and alcohol abuse were found identified. However, there was a higher incidence of previous smoking in the EO-AD group. Numerous co-morbid medical conditions were associated with AD. Hypertension, congestive heart failure, myocardial infarction, and arrhythmia were more prominent in LO-AD, while seizure disorder was found to be more prominent in EO-AD. There was a predominance of cerebral amyloid angiopathy in the LO-AD group. The most common associated neuropathologic finding in both EO-AD and LO-AD was cerebral atherosclerosis.