Clinical Correlation Between Vertical Gaze Palsy and Midbrain Volume in Progressive Supranuclear Palsy

Area of Science:

• Neuro-ophthalmology
• Neuroimaging
• Neurology

Background:

• Progressive supranuclear palsy (PSP) is characterized by vertical gaze palsies and slowed vertical saccades.
• Midbrain atrophy, indicated by the "hummingbird sign," is a classic radiographic finding in PSP.
• The clinical utility of correlating midbrain structure with ocular-motor disturbances for diagnosing PSP remains unclear.

Purpose of the Study:

• To investigate the correlation between midbrain structure and ocular-motor disturbances in patients with progressive supranuclear palsy.
• To determine if this correlation can assist neuro-ophthalmologists in diagnosing difficult cases.

Main Methods:

• Retrospective study of patients diagnosed with probable PSP.
• Neuroradiologist calculated brainstem volumes (midbrain, tegmentum, tectum, medulla) from MRI scans.
• Spearman correlations assessed the relationship between eye movement limitations and brainstem volumes.

Main Results:

• PSP patients showed significantly reduced midbrain, tegmentum, tectum, and medulla volumes compared to controls.
• Midbrain atrophy significantly correlated with the PSP rating scale.
• Midbrain atrophy severity correlated significantly with the extent of upward gaze limitation.

Conclusions:

• The severity of upward gaze limitation is directly related to the degree of midbrain atrophy in PSP patients.
• Recognizing this correlation can aid in resolving diagnostic uncertainties and guiding further investigations in PSP.