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.

Cortical atrophy differentiates Richardson's syndrome from the parkinsonian form of progressive supranuclear palsy.

To determine whether brain atrophy differs between the two subtypes of progressive supranuclear palsy (PSP), Richardson's syndrome (PSP-RS), and PSP parkinsonism (PSP-P), and whether such atrophy directly relates to clinical deficits and the severity of tau deposition. We compared 24 pathologically confirmed PSP cases (17 PSP-RS and 7 PSP-P) with 22 controls from a Sydney brain donor program. Volume loss was analyzed in 29 anatomically discrete brain regions using a validated point-counting technique, and tau-immunoreactive neurons, astrocytes and oligodendrocytes/threads semiquantified. Correlations between the two pathological measures and the presence or absence of cardinal PSP symptoms were investigated. Cortical atrophy was more severe in PSP-RS than PSP-P and affected more frontal lobe regions (frontal pole, inferior frontal gyrus). The supramarginal gyrus was atrophic in both subtypes. Additionally, atrophy of the internal globus pallidus, amygdala, and thalamus was more severe in PSP-RS. As expected, more severe frontal lobe tau pathology differentiated PSP-RS from PSP-P. No correlations were found between the degree of atrophy and severity of tau pathology in any region assessed, or between the severity of atrophy or tau pathology and the presence or absence of cardinal PSP symptoms. Our study shows that thalamocortical atrophy is a defining feature of PSP-RS, but this atrophy does not correlate with the presence of any specific cardinal clinical feature. Interestingly, there is a disassociation between tau pathology and atrophy in the brain regions affected in PSP-RS that requires further investigation.

Low serum progranulin predicts the presence of mutations: a prospective study.

Serum progranulin is decreased in frontotemporal dementia (FTD) patients with progranulin gene (PGRN) mutations. We investigate the utility of prospective serum screening as a surrogate diagnostic marker for progranulin mutations. A commercial ELISA was used to measure progranulin protein concentration in serum from 63 FTD patients and 32 normal controls, and DNA screening then performed. Four patients (2/17 behavioral variant, 2/8 corticobasal syndrome) had abnormally low progranulin levels with PGRN mutations confirmed on DNA testing. Surprisingly, elevated levels were found in 6/16 patients with progressive non-fluent aphasia, the significance of which is unclear. Serum testing is an accurate and cost effective means of predicting PGRN mutations.

Staging disease severity in movement disorder tauopathies: brain atrophy separates progressive supranuclear palsy from corticobasal degeneration.

The movement disorders progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) both deposit tau in degenerating neurons and are considered to be tauopathies. The recently developed scheme for staging tissue degeneration in another tauopathy, frontotemporal dementia [Broe et al., Neurology 2003;60:1005-1011] was applied to pathologically confirmed PSP (n = 24) and CBD (n = 9) cases and correlated with clinical indices. In contrast to frontotemporal dementia, the majority of PSP cases had limited or no visible atrophy, while the pattern of atrophy in CBD cases conformed to the existing staging scheme (all but one case exhibiting substantial visible tissue atrophy). Despite similar clinical severity and disease duration between groups, there was a marked difference between the PSP and CBD cases in pathological disease stage (chi(2) = 8.86; P = 0.03). The degree of global atrophy in PSP appears to be distinct from other tauopathies, while CBD fits the same pattern as other pathological forms of frontotemporal dementia.