Secondary blepharospasm, analysis and pathophysiology of blepharospasm.

PURPOSE

To localize the brain structures involved in blepharospasm.

MATERIALS AND METHODS

This is a retrospective consecutive series of brain MRI's of patients with secondary blepharospasm whose immediate past medical history included cerebrovascular accident or head trauma.

RESULTS

Six patients, including 4 with CVA with ischemic or hemorrhagic lesions of the thalamus and caudate nuclei and 2 with head trauma with contusive sequellae to the tectal plate and frontal cortical and cerebellar atrophy.

CONCLUSION

According to the literature, brain lesions associated with blepharospasm involve mainly the thalamus, head of the caudate nucleus, corpus striatum, globus pallidus, internal capsule, cerebral cortex and cerebellum. This study demonstrates that blepharospasm is associated with a lesion of a complex neural network - cortex-thalamus-globus pallidus-cortex - and does not correspond to a single, unique lesion. This network is connected with ascending and descending sensory-motor pathways and motor nuclei.