Health-related quality of life in facial palsy: translation and validation of the Dutch version Facial Disability Index.

PURPOSE: Patient-reported outcome measures are essential in the evaluation of facial palsy. Aim of this study was to translate and validate the Facial Disability Index (FDI) for use in the Netherlands. METHODS: The FDI was translated into Dutch according to a forward-backward method. Construct validity was assessed by formulating 22 hypotheses regarding associations of FDI scores with the Facial Clinimetric Evaluation scale, the Synkinesis Assessment Questionnaire, the Short Form-12 and the Sunnybrook Facial Grading System. Validity was considered adequate if at least 75% (i.e. 17 out of 22) of the hypotheses were confirmed. Additionally, confirmatory factor analysis was performed. Cronbach's α was calculated as a measure of internal consistency. Participants were asked to fill out the FDI a second time after 2 weeks to analyse test-retest reliability. Lastly, smallest detectable change was calculated. RESULTS: In total, 19 hypotheses (86.4%) were confirmed. Confirmatory factor analysis showed acceptable fit for the two factor structure of the original FDI (root mean square error of approximation = 0.064, standardized root mean square residual = 0.081, comparative fit index = 0.925, Chi-square = 50.22 with 34 degrees of freedom). Internal consistency for the FDI physical function scale was good (α > 0.720). Internal consistency for the FDI social/well-being scale was slightly less (α > 0.574). Test-retest reliability for both scales was good (intraclass correlation coefficients > 0.786). Smallest detectable change at the level of the individual was 17.6 points for the physical function and 17.7 points for the social/well-being function, and at group level 1.9 points for both scales. CONCLUSION: The Dutch version FDI shows good psychometric properties. The relatively large values for individual smallest detectable change may limit clinical use. The translation and widespread use of the FDI in multiple languages can help to compare treatment results internationally.

Association of Socioeconomic, Personality, and Mental Health Factors With Health-Related Quality of Life in Patients With Facial Palsy.

Importance: Knowledge of factors associated with health-related quality of life in patients with facial palsy may aid in better interpreting outcomes of research and treatment. Objective: To identify factors associated with health-related quality of life in patients with facial palsy. Design, Setting, and Participants: The inclusion period for participants in this cross-sectional study at the University Medical Center Groningen, a tertiary referral center for facial reanimation surgery, was March 1 to June 1, 2019. Patients aged at least 18 years with facial palsy who had undergone surgery for facial palsy between January 1, 2007, and January 1, 2018, and patients visiting the outpatient clinic of the University of Groningen Department of Plastic Surgery for their facial palsy between March 1 and June 1, 2019, were also asked to participate. Of 276 patients invited, 145 gave informed consent. Twenty patients did not respond after consent, 3 patients withdrew from the study, and 1 patient was wrongly included. Main Outcomes and Measures: Health-related quality of life was measured using the Facial Clinimetric Evaluation Scale and the Facial Disability Index (physical score and social score). Facial function was assessed with the Sunnybrook Facial Grading System. Other variables were investigated using validated questionnaires, including the Duke University Religion Index, Ten-Item Personality Inventory, and Hospital Anxiety and Depression Scale. Multivariable linear regression analyses with stepwise backward selection were performed to identify associations with health-related quality of life. Because 44 Sunnybrook composite scores were missing, a sensitivity analysis was performed that excluded the Sunnybrook composite scores from the multivariable analysis. Results: In total, 121 patients with facial palsy were included; their median age was 62 years (interquartile range, 48-71 years), and 63 (52%) were women. Sunnybrook composite score (ß = 0.4; 95% CI, 0.2-0.5), extraversion (ß = 2.6; 95% CI, 0.4-4.8), and anxiety (ß = -2.4; 95% CI, -4.1 to -0.8) were associated with the Facial Clinimetric Evaluation Scale total score (R2 = 0.380; 95% CI, 0.212-0.548). The Sunnybrook composite score was associated with the Facial Disability Index physical score (ß = 0.2; 95% CI, 0.0-0.4) (R2 = 0.084; 95% CI, -0.037 to 0.205). Bilateral facial palsy (ß = -21.2; 95% CI, -32.3 to -10.1), extraversion (ß = 2.7; 95% CI, 1.3-4.1), conscientiousness (ß = 2.7; 95% CI, 0.2-5.2), emotional stability (ß = 3.3; 95% CI, 1.7-4.8), and depression (ß = -1.3; 95% CI, -2.5 to -0.1) were associated with the Facial Disability Index social score (R2 = 0.400; 95% CI, 0.262-0.538). In the sensitivity analysis, the Sunnybrook composite score was associated with age (Spearman ρ = -0.252). Conclusions and Relevance: Bilateral facial palsy, age, severity of facial palsy, mental distress, and personality traits should be taken into account in future research and treatment of patients with facial palsy.