Secondary blepharospasm, analysis and pathophysiology of blepharospasm
B Girard1, O Davoudi2, M Tatry1
1Service d'ophtalmologie, Sorbonne université, hôpital Tenon, AP-HP, 4, rue de la Chine, 75020 Paris, France.
Journal Francais D'Ophtalmologie
|December 22, 2020
Summary
Brain lesions in blepharospasm involve a complex neural network, not a single site. This study highlights the cortex-thalamus-globus pallidus-cortex pathway in blepharospasm.
Area of Science:
- Neuroscience
- Neurology
- Medical Imaging
Background:
- Blepharospasm is a focal dystonia characterized by involuntary eyelid closure.
- Previous literature suggests various brain structures are implicated in blepharospasm.
Purpose of the Study:
- To identify and localize specific brain structures associated with secondary blepharospasm.
- To elucidate the neural network underlying blepharospasm.
Main Methods:
- Retrospective analysis of brain Magnetic Resonance Imaging (MRI) scans.
- Inclusion criteria: patients with secondary blepharospasm and a history of cerebrovascular accident (CVA) or head trauma.
Main Results:
- Four patients with CVA showed ischemic or hemorrhagic lesions in the thalamus and caudate nuclei.
- Two patients with head trauma exhibited contusive sequelae affecting the tectal plate, frontal cortex, and cerebellar atrophy.
- Findings suggest lesions in the thalamus, caudate nuclei, tectal plate, frontal cortex, and cerebellum.
Conclusions:
- Blepharospasm is linked to lesions within a complex neural network, specifically the cortex-thalamus-globus pallidus-cortex circuit.
- The identified network connects with ascending and descending sensory-motor pathways and motor nuclei.
- Blepharospasm is not attributed to a single lesion but rather a disruption within this intricate neural system.
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