Validation of a short disease specific quality of life scale for hemifacial spasm: correlation with SF-36

BACKGROUND: A short, practical, and validated quality of life (QoL) scale for hemifacial spasm (HFS) is not currently available. OBJECTIVES: To examine the reliability and validity of a short self-rating scale (HFS-7) by comparing HFS patients with healthy controls. We also evaluated the correlation of HFS-7 with the physical and mental domains of SF-36, a generic QoL scale. METHODS: Seven self-rating items (HFS-7) were administered to HFS patients and healthy controls. In addition, HFS patients answered the SF-36 questionnaire. The validity and reliability of HFS-7 were analysed and correlation between HFS-7 and SF-36 examined. RESULTS: A total of 178 subjects were enrolled in the study, including 85 HFS patients with mean age of 54.8 (SD 11.0) years, of whom 52 (61.2%) were women, and 93 controls with mean age of 51.4 (SD 10.0) years, of whom 59 (63.4%) were women. The test-retest intraclass correlation coefficient for the seven items was between 0.75 and 0.90 and Cronbach's coefficient of reliability for the HFS-7 scale was 0.88. Every item in HFS-7 discriminated between disease and controls (p<0.0001). The HFS-7 summary index correlated with the SF-36 summary score (Spearman's correlation r = -0.28, p = 0.009), in particular the mental health summary score (r = -0.416, p<0.0001) and the emotional domain (r = -0.466, p<0.00001). CONCLUSION: HFS-7 could prove useful as a simple clinical tool to assess and monitor QoL measures in HFS patients.