Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Validity

Abstract

To present evidence of the reliability and validity in the Spectrographic Vocal Assessment Protocol. The sample consisted of 50 female participants, aged 25-62 years old, 24 with a otorhinolaryngological diagnosis of the normal larynx or posterior glottal gap, and 26 diagnosed with vocal fold disturbances. The emission of the vowel /a:/ was analyzed by the Real Time Spectrogram software. The spectrographs were analyzed with a protocol by two speech therapist judges. For reliability analysis, inter- and intrajudge analysis were performed using the Kendall coefficient. For criterion validity, the t test for matched samples with Bonferroni correction was used to compare the average performance of the protocol between the two groups of subjects. Protocol reliability: for broadband items, the agreement between judges ranged from moderate (0.462) to almost perfect (0.888), and it is significant for all items, and an intrajudge agreement was almost perfect and significant (0.865-1.000) for all items. For narrowband items, the agreement between judges ranged from moderate (0.469) to almost perfect (0.922), and it is significant for all items except for the presence of "subharmonics in high frequencies" where agreement was moderate (0.504), but not significant, and the intrajudge agreement was almost perfect (0.874-1.000) and significant for all items. Criterion validity: for most broadband and narrowband items, the groups with normal or altered diagnosis differed statistically. The Spectrographic Vocal Assessment Protocol presented adequate evidence in reliability and validity.