Asian over-representation among patients with hemifacial spasm compared to patients with cranial-cervical dystonia.

BACKGROUND AND PURPOSE Hemifacial spasm (HFS) is a common movement disorder, but its prevalence in different populations has not been elucidated. METHODS We reviewed all patients with HFS currently followed at the Baylor College of Medicine Movement Disorders Clinic and compared their demographic and clinical data with a control group of patients with cranial-cervical dystonia (CD). RESULTS In contrast to patients with CD (N=145, mean age 48.64±13.61 years), of whom 117 (80.69%) were Caucasians, 13 (8.97%) Hispanic, 10 (6.90%) African-American, and 5 (3.45%) were of Asian origin, there were 81 (61.36%) Caucasians, 24 (18.18%) Hispanic, 13 (9.85%) African-Americans, and 14 (10.61%) Asians in the HFS group (N=132, mean age 49.33±13.25). Although there was no statistical difference in the age and gender distribution between the two groups, the frequency of Asians in HFS group was 3.1 times higher than that in CD group (P<0.01). Furthermore, the prevalence of Asians among patients with HFS was nearly twice the estimated prevalence of Asians in a general Houston population (5.48%). CONCLUSION Our results support the observation that HFS is much more common in the Asian population than in other populations. Further epidemiological, genetic, imaging and anatomic studies are needed to understand the apparent difference in the prevalence of this peripherally induced movement disorder.