Inter-hemispherical comparison of tau-pathology in the human temporal lobe

Alzheimer's disease (AD) is characterized histopathologically by hyperphosphorylated and aggregated Tau and amyloid plaques. While the latter appear in a less stringent way throughout the brain in the course of the disease, the former evolve in a highly predictable pattern as described by Braak and Braak (1991). It is, however, not clear if this pattern develops simultaneously in both hemispheres. In this study, we therefore compared Tau-pathology of both hemispheres of the same individual in 36 consecutive brain donations as they arrived in our brain bank. 26 exhibited little differences, in eight cases left hemisphere was clearly more affected and in two cases the right hemisphere. Thus, cases with evident interhemispheric Tau-pathology do exist and interhemispheric comparison in such cases may help to identify driving forces in the progression of AD.