A Review of: Tongue Thrust in Swallowing and Speaking, by Samuel G. Fletcher (1974)

Objective: To determine if auditory-perceptual voice ratings performed using the GRBAS scale correlate with acoustic and aerodynamic measures of voice. A secondary aim was to examine the relationship between GRBAS ratings and patient-reported quality of life measures. Methods: GRBAS ratings, acoustic, aerodynamic and patient-reported quality of life measures were collected from the University of Wisconsin Madison Voice and Swallow Outcomes Database for 508 adults with voice disorders. Acoustic measures included noise to harmonic ratio, jitter%, shimmer%, highest frequency of vocal range, lowest frequency of vocal range, maximum phonation time and dysphonia severity index (DSI). Aerodynamic measures included phonation threshold pressure, subglottal pressure, mean transglottal airflow and aerodynamic resistance. Patient-reported quality of life measures included the Vocal Handicap Index (VHI) and Glottal Function Index (GFI). Results: GRBAS ratings were significantly correlated with several acoustic and aerodynamic measures, VHI and GFI. The strongest significant correlations for overall voice quality were observed between GRBAS ratings of overall voice quality, and perturbation measures (jitter% r² = 0.24, shimmer% r² = 0.30, NHR r² = 0.24), DSI (r² = 0.29), and vocal frequency range (r² = 0.36). GRBAS ratings of over-all voice quality were also significantly correlated with transglottal airflow (r² = 0.15) and subglottal pressure (r² = 0.15), as well as both VHI (r² = 0.23) and GFI scores (r² = 0.20). Conclusions: Although GRBAS ratings were significantly correlated with multiple objective voice and patient related quality of life measures, r 2 values were in low to medium range across all correlations. These findings support the need for multiple voice measures when performing voice evaluations as no single voice measure explained high amounts of variation in voice quality as measured by the GRBAS scale.