Associations between neuropsychological profile and regional brain FDG uptake in progressive supranuclear palsy

BackgroundProgressive supranuclear palsy (PSP) is a rare neurodegenerative movement disorder clinically characterized by falls, axial rigidity, vertical supranuclear gaze palsy, bradykinesia, and cognitive decline. There is a relative lack of studies on the functional neuroimaging correlates of cognitive impairment in PSP.ObjectiveThis study investigated the relationship between regional cerebral glucose metabolism as assessed by static ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) with global scaling and the profile of cognitive performance according to the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) test battery in a sample of PSP patients representative of clinical practice.Methods22 PSP patients from three tertiary movement disorder centers with CERAD testing and FDG-PET in close proximity were included retrospectively. Neuropsychological test performance was assessed for correlation with FDG uptake on a voxel-by-voxel basis with cluster-level correction for multiple testing, separately for each subtest.ResultsIn comparison to matched healthy controls, PSP patients showed reduced FDG uptake in the left inferior frontal gyrus and right angular gyrus. Reduced overall cognitive performance according to Montreal Cognitive Assessment was associated with reduced FDG uptake in the right frontal eye field. Word list learning correlated with FDG uptake in the left frontal eye field, while language fluency was linked to FDG uptake in the bilateral premotor and supplementary motor areas.ConclusionsReduction of FDG uptake in PSP primarily affects frontal brain regions and is linked to the performance in specific cognitive domains. These findings may have implications for the interpretation of FDG-PET to support the etiological diagnosis of PSP.