1. The incidence of hemifacial spasm is approximately 0.8 per 100, 000 persons. 2. Botulinum toxin is highly effective in the treatment of hemifacial spasm . 3. Hemifacial spasm is much more common in some Asian populations.4. Patients with hemifacial spasm were shown to have decreased sweating after botulinum toxin injections. 5. MRI imaging should be the initial screening procedure in the assessment of patients with hemifacial spasm . 6. Imaging procedures should be done in all unusual cases of hemifacial spasm and when surgery is contemplated. 7. Besides hemifacial spasm , botox can help other diseases, including ones that involve involuntary muscle contractions or spasms. 8. Like blepharospasm, the frequency of contractions in hemifacial spasm may range from intermittent to frequent and constant. 9. Microvascular decompression relieves pressure on the facial nerve, which is the cause of most hemifacial spasm cases. 10. In 1977, 47 cases of hemifacial spasm underwent microvascular decompression of the facial nerve using the operating microscope.