The relationship between clinical and pathological variables in Richardson's syndrome

In order to determine the relationship between regional neuropathology and severity of clinical features in Richardson's syndrome (PSP-RS), the following hypotheses were tested: (1) executive dysfunction relates to prefrontal pathology; (2) language difficulties to pathology in Broca's area and/or the perirhinal cortex; and (3) visuospatial impairment to pathology in the supramarginal region. A prospectively studied case series of brain donors at a specialist clinic in Addenbrooke's Hospital Cambridge, UK, were examined. All those fulfilling postmortem criteria for PSP-RS and their last cognitive assessment within 24 months of death (N = 11/25) were included. The degree of regional neuronal loss and neuronal tau deposition across a number of cortical brain regions was performed and compared to 10 age- and sex-matched controls from the Sydney Brain Bank. Stepwise multiple linear regressions were used to determine the neuropathological correlates to cognitive scores and revealed the following. Executive dysfunction, as indexed by letter fluency, related to the degree of tau deposition in the superior frontal gyrus and supramarginal cortices (p < 0.020), language deficits related to neuron loss in the perirhinal gyrus (p < 0.001) and tau deposition in Broca's area (p = 0.020), while visuospatial dysfunction and global cognitive impairment related to tau deposition in the supramarginal gyrus (p < 0.007). The severity of cognitive deficits relate to regional cortical tau deposition in PSP-RS, although language impairment related to neuronal loss in the perirhinal region. Global cognitive dysfunction related most to the severity of tau deposition in the supramarginal gyrus warranting further research on the role of this brain region in PSP-RS.