Comprehensive Index of Vocal Fatigue (CIVF): Development and Clinical Validation

In this study, we sought to investigate whether auditory-perceptual and acoustic measures change after a passage-reading task and to develop a multidimensional index of performance fatigue in voice disorders. The clinical usefulness and cut-off scores of the newly developed index were also explored.

A total of 150 patients (age = 35.65 ± 11.44 years) with voice disorders and 100 healthy controls (age = 35.04 ± 11.26 years) were enrolled in the study. Overall severity (OS) and acoustic measures of sentence samples were obtained before and after a passage-reading task and compared between the two positions. Acoustic features included cepstral peak prominence (CPP), σCPP, L/H spectral ratio (SR), and σSR. Using the changes (Δ) in those acoustic measures and the scores of the Vocal Fatigue Index (VFI), a predictive model of the ΔOS was established. The clinical cut-off point of the index was also identified.

For the patient group, OS was higher, but CPP and σCPP were lower for the rear position (after reading the passage) compared to the front position (before reading the passage). A significant portion (adjusted R² = 77.7%) of the ΔOS was predicted by ΔCPP, tiredness score of the VFI, ΔσCPP, ΔσSR, and ΔSR. The area under the curve of the newly developed index was .864 (sensitivity, 78.67%; specificity, 78.00%), and the index's criterion was >2.6489.

The newly developed Comprehensive Index of Vocal Fatigue (CIVF) can quantify vocal fatigue in voice disorders, reflecting both acoustic and auditory perceptual changes after a passage-reading task. Further studies should explore the responsiveness of the CIVF and the impact of related factors on the CIVF in various voice disorders.