Validity and Reliability of the Arabic Version of the Glottal Function Index in Dysphonic Patients

The Glottal Function Index (GFI) is a four-item self-administered survey suitable for the evaluation and treatment of patients with glottal dysfunction. To date, it has been translated into Lithuanian, Persian, and Hebrew. This study is intended to translate and cross-culturally adapt the GFI for use in Arabic-speaking patients with dysphonia.

This work is a cross-sectional study involving the administration of the GFI to participants with dysphonia (cases) and patients without dysphonia (controls). The validation process included reliability and validity assessments.

The GFI was translated using forward and backward translation methods from English into Arabic. The questionnaire's reliability was assessed using Cronbach's alpha and test-retest reliability (intraclass correlation coefficient, ICC). The Mann-Whitney test evaluated validity by comparing cases and controls. Finally, the Kruskal-Wallis test examined differences in the GFI across various pathologies.

The GFI demonstrated favorable internal consistency (Cronbach's alpha = 0.848) and excellent test-retest reliability (ICC = 0.993). Significant differences in the A-GFI score between the cases and controls were also observed (P < 0.001), supporting the instrument's validity. However, no statistically significant differences were found in A-GFI across different diagnoses (P = 0.712).

The A-GFI is a valid and reliable screening tool for clinicians to assess dysphonia and voice impairment in patients in Arabic-speaking countries. The tool is easy to administer in daily clinical practice given its brevity and self-administration.