Validation of GSLBI (Grade, Strained, Leaky, Breathy, Irregular): an Egyptian instrument for auditory perceptual assessment of voice

Abstract Background The human voice is expected to be perceived as healthy and free from noticeable deviations that may indicate dysphonia. Dysphonia, or a voice disorder, is best defined as a change in an individual’s voice accompanied by vocal complaints, functional limitations, or communication difficulties. A trained ear serves as the primary tool for detecting and describing dysphonia, making auditory-perceptual assessment (APA) a crucial component in both clinical and research settings. It is widely recognized as the first step in voice evaluation. One of the most commonly used tools for APA in voice clinics is the Grade-Roughness-Breathiness-Asthenia-Strain (GRBAS) scale, developed by the Japanese Phoniatrics and Logopedics Committee in 1981. This scale consists of five distinct parameters, each rated on a four-point Likert scale (0 = no deviation, 1 = mild, 2 = moderate, 3 = severe). However, GRBAS lacks standardization. Twenty years ago, professor Dr. Nasser Kotby, the founder of the phoniatrics specialty in Egypt and the Middle East, introduced a modified version of GRBAS known as GSLBI (Grade, Strained, Leaky, Breathy, Irregular). This adaptation also incorporated evaluations of pitch and loudness and has since been used in auditory-perceptual assessment at the Phoniatrics Unit, Faculty of Medicine, Ain Shams University. Another widely utilized perceptual voice assessment tool is the Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V), developed by the American Speech-Language-Hearing Association (ASHA) in 2002. CAPE-V introduced a more diverse and standardized protocol. The present study aims to evaluate the validity of GSLBI as an Egyptian auditory-perceptual assessment tool by incorporating a standardized protocol similar to CAPE-V, including running speech, Egyptian phonetically designed sentences, and sustained vowels. Results The findings indicate that GSLBI, when applied with the new standardized protocol, is a valid and reliable tool for auditory-perceptual voice assessment. It demonstrated good validity and acceptable reliability in the dysphonic group (Cronbach’s α = 0.758). Test-retest reliability, assessed through intra-rater agreement, showed moderate consistency across repeated evaluations by the same rater. Inter-rater reliability demonstrated moderate agreement across most categories, reflecting consistent ratings between different raters. A significant difference was observed in GSLBI ratings between dysphonic patients and healthy controls, supporting the tool’s ability to distinguish between the two groups. The only parameter that did not demonstrate either validity or reliability was “breathy,” likely due to its low occurrence in the studied dysphonic sample. Conclusion GSLBI is a validated and reliable tool for auditory-perceptual voice assessment. Its application with a structured protocol enhances its clinical utility, making it a valuable tool for dysphonia evaluation.