FDG-PET in Different Clinical Phenotypes of Progressive Supranuclear Palsy (P04.157)

OBJECTIVE: To compare the brain glucose metabolism (FDG-PET) of the different variants of PSP. BACKGROUND: Progressive supranuclear palsy (PSP) is a clinical syndrome characterized by falls, supranuclear gaze palsy, axial rigidity, frontal dementia, and poor response to levodopa. This classical phenotype is often observed in the later stage of the disease but a clinical heterogeneity is reported in the early stage and several clinical variants are described: Richardson9s syndrome (RS), PSP-parkinsonism (PSP-P), PSP pure akinesia with gait freezing (PAGF), PSP-corticobasal syndrome (PSP-DCB), and PSP with non-fluent aphasia parkinsonism variant (PNFA). PSP is a primary tauopathy and the phenotype varies probably according to distribution of cerebral tau pathology. To the best of our knowledge, there is no study comparing the brain glucose metabolism in all different PSP phenotypes in the early stage of disease. DESIGN/METHODS: Between December 2009 and July 2011, consecutive patients with clinically suspected PSP and disease duration less than 3 years underwent FDG-PET. All patients were examined by movement disorder specialists. According to the initial clinical features, patients were divided in five sub groups: RS, PSP-P, PAGF, PSP-DCB and PNFA. FDG-PET were independently interpreted by 2 investigators. RESULTS: Thirty-two patients were included: 18 RS patients, 5 PSP-P patients, 5 PAGF patients, 3 PSP-DCB patients, and 1 PNFA patient. Median age was 72 years. Median disease duration at time of imaging was 2.5 years. The FDG-PET images, analyzed with SPM2, demonstrated a bilateral glucose metabolism in frontal cortex compared to healthy age-matched controls. No statistically significant difference in brain glucose metabolism was observed between the five PSP phenotypes. CONCLUSIONS: In our PSP patients with different clinical phenotypes, FDG-PET showed bilateral hypometabolism frontal cortex. This pattern was earlier described in the classical PSP phenotype. The similar metabolic FDG-PET pattern in patients with different clinical PSP phenotypes is in favour of a shared pathophysiological mechanism. Disclosure: Dr. De Verdal has nothing to disclose. Dr. Boudousq has nothing to disclose. Dr. Renard has nothing to disclose. Dr. Taieb has nothing to disclose. Dr. Collombier has nothing to disclose. Dr. Castelnovo has nothing to disclose.