Vertical gaze palsies from medial thalamic infarctions without midbrain involvement

Area of Science:

• Neuroscience
• Ophthalmology
• Radiology

Background:

• Vertical gaze palsies are typically associated with lesions in the mesencephalic reticular formation, including specific nuclei and pathways.
• The supranuclear pathways controlling vertical gaze are not fully understood.
• Previous MRI studies have not identified isolated thalamic lesions as a cause of vertical gaze palsies.

Observation:

• This study utilized MRI to investigate three patients presenting with acute vertical gaze paralysis.
• Imaging included sagittal T1 and axial T1, T2, and proton-weighted sequences, with follow-up scans.
• Two patients had unilateral right thalamic infarcts, and one had bilateral paramedian thalamic infarction, with no midbrain involvement.

Findings:

• MRI revealed thalamic infarctions in three patients with vertical gaze palsies.
• No evidence of associated midbrain lesions was found in these patients.
• This contrasts with the established understanding linking vertical gaze palsies to midbrain structures.

Implications:

• Thalamic lesions, specifically infarctions, can lead to vertical gaze palsy.
• This suggests that interruptions in supranuclear inputs to the vertical gaze pathways may be responsible.
• The findings broaden the understanding of the neuroanatomical basis of vertical eye movement disorders.