Purpose: The aim of this study was to explore the diagnostic value of the combination of Acoustic Voice Quality Index (AVQI) and Glottal Function Index (GFI) as a screening tool for voice disorders, and to compare the AVQI measurements obtained using oral and smartphone (SP) microphones.
Methods: A study group consisted of 183 adult individuals including 86 subjects with normal voice and 97 patients with pathological voice. Voice recordings were performed simultaneously with an oral AKG Perception 220 and SP iPhone 6s microphones. To evaluate the diagnostic accuracy differentiating normal and pathological voice, the receiver-operating characteristic statistics [area under curve (AUC), positive and negative likelihood ratios (LR+ and LR-)], and correct classification rate (CCR) were used.
Results: The AVQI cut-off scores of 3.31 for oral and 3.32 for SP microphones were associated with very good test accuracy (AUC = 0.857 and AUC = 0.818), resulting in balance between sensitivity and specificity (70.0% vs 86.0% and 70% vs 87.0%). The CCR reached 78%. The combined AVQI and GFI cut-off scores of 6.65 for oral and 7.1 for SP microphones corresponded with excellent test accuracy (AUC = 0.976 and AUC = 0.965) and sensitivity and specificity (93.0% vs 93.0% and 91.0% vs 94%). Very respectable levels of LR+ and LR- both for oral microphone (13.3 and 0.08) and for SP microphone (15.6 and 0.10) voice recordings were achieved. CCRs of 93% and 92% confirmed the results of ROC statistics.
Conclusions: Combination of AVQI and GFI measurements significantly improved diagnostic accuracy in differentiating normal vs pathological voice.
Keywords: AVQI; Automated voice screening; GFI; Voice analysis.