THE CONSORTIUM TO ESTABLISH A REGISTRY FOR ALZHEIMERS-DISEASE (CERAD).9. A PROSPECTIVE CLINICONEUROPATHOLOGICAL STUDY OF PARKINSONS FEATURES IN ALZHEIMERS-DISEASE

Although extrapyramidal signs such as rigidity, bradykinesia, and post ural impairment frequently occur in patients with Alzheimer's disease (AD), the correlation of these parkinsonian manifestations with the ne uropathologic changes of Parkinson's disease (PD) has not been well es tablished. Previous clinicopathologic studies addressing this issue ha ve been largely retrospective or have consisted of relatively small nu mbers of cases, We examined the neuropathologic correlates of clinical parkinsonism in 78 cases with autopsy-confirmed AD prospectively enro lled in the Consortium to Establish a Registry for Alzheimer's Disease . Sixteen (20.5%) of the 78 AD cases showed concomitant PD pathology ( AD/PD) as evidenced by the presence of nigral degeneration and Lewy bo dies at any site. There were neocortical Lewy bodies in eight of these 16 cases. Two or more clinical manifestations of extrapyramidal dysfu nction were present in eight (50.0%) of the 16 cases of AD/PD versus 1 1 (17.7%) of the 62 cases of AD alone (p < 0.01). Although semiquantit ative ratings of the frequency of neuritic plaques showed no differenc es between the two groups, neurofibrillary tangles in the AD/PD group were less frequent in the midfrontal (p < 0.001) and superior temporal cortex (p < 0.05). These findings support previous reports that AD/PD cases are more likely to manifest extrapyramidal dysfunction and show plaque predominance at autopsy.