Brain FDG-PET correlates of saccadic disorders in early PSP

New diagnostic criteria of Progressive Supranuclear Palsy (PSP) have highlighted the interest of Eye Movement Records (EMR) at the early stage of the disease.

To investigate the metabolic brain correlates of ocular motor dysfunction using [18F] Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) in early PSP.

Retrospective observational descriptive study on longitudinal data with patients who underwent EMR and FDG-PET at the stage of suggestive and possible PSP according to Movement Disorders Society criteria. Longitudinal follow-up enables to confirm diagnosis of probable PSP. Using the Statistical Parametric Mapping software, we performed whole-brain voxel-based correlations between oculomotor variables and FDG-PET metabolism.

Thirty-seven patients with early PSP who fulfilled criteria of probable PSP during the follow-up were included. Decrease in the gain of vertical saccades correlated with reduced metabolism in Superior Colliculi (SC). We also found a positive correlation between mean velocity of horizontal saccades and SC metabolism as well as dorsal nuclei in the pons. Finally, increase in horizontal saccades latencies correlated with decrease of posterior parietal metabolism.

These findings suggest the early involvement of SC in saccadic dysfunction in the course of PSP.