Clinical Symptoms and Differential Diagnosis of Hemifacial Spasm

Hemifacial spasm (HFS) is characterized by brief, repetitive, and involuntary tonic–clonic contraction of unilateral facial expression muscles. The diagnosis of HFS should be made based on the clinical history and typical symptoms of the disease. Visible symptoms of HFS often initiate with twitching of the lower eyelid and spreads to the upper and lower facial areas. Occasionally, misdiagnosis of HFS as another hyperkinetic facial movements, including blepharospasm, post-paralytic facial synkinesis, facial motor tics, facial myokymia, oromandibular dystonia, facial myoclonus, hemimasticatory spasm, myorhythmia, and functional facial spasm can occur. The presence of “the other Babinski sign” and synchronous contraction of the upper and lower facial muscles are considered specific to HFS. And the absence of red-flag signs of HFS, provocation maneuvers, and taking home videos are useful to facilitate precise initial diagnosis. In this chapter, we reviewed the clinical features and the differential diagnoses of HFS to ensure a precise diagnosis.