Mapping Regional Grey and White Matter Damage in Patients with Progressive Supranuclear Palsy Syndrome (S57.007)

OBJECTIVE: To investigate the pattern of grey matter (GM) atrophy and white matter (WM) microstructural damage in a patients with probable progressive supranuclear palsy syndrome (PSPs) using advanced magnetic resonance imaging (MRI) techniques. BACKGROUND: The PSPs falls under the umbrella of frontotemporal lobar degeneration (FTLD) clinical spectrum. Pathological and neuroimaging studies suggested that in syndromes with an underlying FTLD-tau pathology, such as PSPs, WM damage is prominent compared to GM loss. DESIGN/METHODS: We enrolled 21 patients with probable PSPs and 21 healthy controls. Patients underwent clinical and neuropsychological evaluation, and brain structural and diffusion tensor (DT) MRI. The regional patterns of brain GM atrophy and WM microstructural damage were assessed using voxel-based morphometry and tract-based spatial statistics, respectively (p<0.05 FWE). RESULTS: PSPs patients were in a moderate stage of disease (mean Hoehn and Yahr score: 3.3) and showed mild to moderate cognitive impairment involving especially attentive-executive functions. PSPs patients did not show significant GM atrophy relative to controls. On the contrary, they showed a significant reduction of fractional anisotropy and a significant increase of mean, axial and radial diffusivities in the main WM tracts bilaterally, including body and splenium of corpus callosum, cingulum, inferior fronto-occipital, superior longitudinal and uncinate fasciculi, anterior and superior corona radiata, corticospinal tract, and thalamic radiations. Superior cerebellar peduncles and internal capsules showed a significant increase of diffusivity values, but no FA changes. CONCLUSIONS: In PSPs patients, WM microstructural damage is prominent compared to GM atrophy even in the moderate stage of the disease, suggesting that diffuse WM damage in tauopathies is not merely a function of disease severity. Regional differences in DT MRI metrics might reflect a different vulnerability of WM tracts. Study Supported by: CurePSP MD505-12_001