Neuropathological background of twenty-seven centenarian brains.

The neuropathological features of 27 centenarian brains were investigated. They were found to have no fundamental differences from the brains of younger elderly individuals. It was noted that 3 centenarian brains showed no apparent senile changes or ischemic lesions and this group was designated "supernormal" centenarians. In contrast, there were 6 centenarian brains with numerous senile plaques in the cerebral cortex, a finding resembling that seen in senile dementia of the Alzheimer type (SDAT). However, these brains had only a few neurofibrillary tangles mainly in the hippocampus and the medial temporal lobe, and therefore were not affected by SDAT. These subjects were not truly demented. It was considered that these brains showed the upper limit of normal ageing, while the "supernormal" centenarians showed the lower limit. In addition, idiopathic Parkinson's disease was diagnosed pathologically in 4 subjects who did not show any clinical symptoms of this disease. Finally, 2 out of 5 cases with dementia developed it secondary to subdural haematoma.