A comparative study of primary and secondary hemifacial spasm

Background: Hemifacial spasm (HFS) is a common movement disorder. Objective: To evaluate possible differences in the demographic and clinical features between primary and secondary HFS. Design: In-person interview using a standardized questionnaire to collect demographic and clinical data. Setting: A multicenter study that included patients with HFS attending 3 Italian academic centers. Patients: Two hundred fourteen patients with HFS. Main Outcome Measure: A complete neurological examination assessed the current muscle distribution of spasm and the presence of synkinetic movements between Upper and lower facial muscles. Results: The stud), sample comprised 214 patients with HFS, 81 men and 133 women, having a mean +/- SD age of 65.9 +/- 12.3 years; 1.64 patients were classified as having primary HFS and 50 patients (48 postparalytic and 2 symptomatic cases) were classified as having secondary HFS. Patients With primary and those with secondary HFS had similar meant +/- SD ages at onset (54.9 +/- 13,5 vs 57.0 +/- 12.8 years), male-female ratios (63: 101 vs 18: 32), right-sided-left-sided HFS (77:86 [1 bilateral] vs 21:28 [1 bilateral]),and frequencies of familial cases (2.9% vs 2.0%), respectively. Most patients (65.0%) with primary HFS had initial symptoms of periocular muscle contractions alone and had subsequent involvement of the lower facial muscles. Most patients (72.0%) with secondary HFS reported initial involvement of the upper and lower facial muscles simultaneously. Signs of synkinesis were present in primary (43.3%) and secondary (58.0%) HFS. Conclusions: Patients with primary and those with secondary HFS share common demographic and clinical features, including sex distribution, age at onset, affected side of HFS, synkinesis, and rarity of familial cases. Signs of synkinesis were present in significant proportions of patients with primary or secondary HFS. The 2 forms differed in clinical presentation