Blepharospasm
Blepharospasm is often treated with botulinum toxin. The condition is classified as a focal dystonia. In Meige’s (Breugel’s) syndrome, blepharospasm is accompanied by oromandibular dystonia.
Similar movements sometimes occur as a tic, habit spasm or stereotypy, especially in adolescents. Blepharospasm may be confused with apraxia of eyelid opening and some patients with essential blepharospasm may have a component of apraxia of eyelid opening characterized by transient failure to voluntarily reopen the eyes without orbicularis spasm. (3) Rarely, the movements in hemifacial spasm are more prominent in the upper face and appear to cause unilateral blepharospasm, but subtle lower facial movements are always present in addition. Facial synkinesis (see http://neurosigns.org/wiki/Facial_synkinesis), as after Bell's palsy, may cause similar confusion (Marin Amat sign).
Video legend. Blepharospasm and blepharospasm with oromandibular dystonia (Meige’s (Breugel’s) syndrome). Video courtesy of Dr. Stephen G. Reich
References
1. Campbell WW. Barohn RJ. DeJong's the neurologic examination, 8th ed. Philadelphia: Wolters Kluwer, 2020.
2. Campbell WW. Clinical signs in neurology: a compendium. Philadelphia: Wolters Kluwer Health, 2016.
3. Defazio G, Hallett M, Jinnah HA, Conte A, Berardelli A. Blepharospasm 40 years later. Mov Disord. 2017;32:498-509