Midbrain atrophy in patients with presymptomatic progressive supranuclear palsy-Richardson's syndrome

Abstract Introduction In the present study, midbrain atrophy and the pons-to-midbrain area ratio (P/M ratio) were investigated as diagnostic markers for presymptomatic progressive supranuclear palsy-Richardson's syndrome (Pre-PSP-RS). Methods The present study included 27 patients with probable PSP-RS who underwent brain MRI at least twice before and after the development of clinical symptoms, age- and sex-matched participants with Parkinson's disease (PD, n = 27), and healthy controls (n = 27). The midbrain area, pons area, and P/M ratio of the Pre-PSP-RS, PD, and control subjects were measured using midsagittal images from brain MRI, and the parameters were compared among the groups. Results The midbrain area decreased and the P/M ratio increased significantly in the Pre-PSP-RS patients compared with both the PD and control subjects (midbrain, Pre-PSP-RS vs . PD = 1.01 cm 2 vs . 1.29 cm 2 , p vs . controls = 1.01 cm 2 vs . 1.29 cm 2 , p vs . PD = 5.27 vs . 4.03, p vs . controls = 5.27 cm 2 vs . 4.06 cm 2 , p vs . PD, 96.3%, vs . control, 88.9%) and specificity ( vs . PD, 81.5%, vs . control, 96.3%) in differentiating Pre-PSP-RS patients from PD and control subjects. Conclusion Midbrain atrophy precedes the clinical symptoms of PSP-RS and could be a useful diagnostic imaging biomarker for Pre-PSP-RS. Furthermore, this information could play an important role in the development of future treatment strategies.