Assessment of voice fatigue by Vocal fatigue Index (VFI)

Ovaj rad bavi se ispitivanjem razlika između rezultata ispitanika s poremećajem glasa različite etiologije i rezultata ispitanika bez poremećaja glasa na hrvatskoj verziji upitnika Indeks vokalnog zamora (VFI). Ukupno je sudjelovalo 119 ispitanika; 69 osoba s poremećajem glasa različite etiologije i 50 osoba bez vokalnih teškoća koje su sačinjavale kontrolnu skupinu. Postavljena je pretpostavka kako će postojati statistički značajna razlika u rezultatima upitnika Indeks vokalnog zamora između skupine ispitanika s poremećajem glasa i skupine ispitanika bez poremećaja glasa (H1). Korištena je subjektivna procjena glasa koja je izvršena metodom samoprocjene glasa. U tu svrhu je s engleskog jezika, prema načelima dvostrukog prijevoda te prema standardima Svjetske zdravstvene organizacije, preveden upitnik Vocal Fatigue Index –VFI. Statističkom obradom dobivena je statistički značajna razlika između dviju skupina ispitanika na svim varijablama upitnika Indeks vokalnog zamora (VFI). Rezultati ukazuju kako je hrvatska verzija upitnika Indeks vokalnog zamora uspješno diferencirala dvije skupine ispitanika čime je potvrđena postavljena pretpostavka istraživanja. Također, koeficijentom unutarnje konzistentnosti utvrđena je visoka unutarnja pouzdanost među česticama. S obzirom na dobivene rezultate, predlaže se dorada hrvatske verzije upitnika, kroz testiranje valjanosti te testiranje na većem broju ispitanika. Takav, pouzdan i valjan upitnik dobrodošao je na polju logopedije koje je usmjereno na poremećaje glasa jer bi se na kvalitetan način koristio u raznim kliničkim uvjetima za identifikaciju pojedinaca s vokalnim zamorom, za procjenu simptoma prije terapije te za mjerenje poboljšanja simptoma nakon terapije.This thesis presents the results of a study that explores the differences in results obtained from participants with voice disorders of varying etiology, and participants with no voice disorders, who completed the Croatian version of the Vocal Fatigue Index (VFI) survey. The study had a total of 119 participants; 69 individuals with voice disorders of varying etiology and 50 individuals with no voice disorders, who made up the control group. The basic hypothesis was that there would be a statistically significant differentce in the results of the VFI survey between the group of participants with a vocal disorder and the group consisting of participants without a vocal disorder (H1). A subjective vocal evaluation was used, which was carried out via the method of self-evaluation. For this purpose, the Vocal Fatigue Index – VFI, was translated from English, in compliance with the standard of double translation, as well as the standards of the World Health Organization. The results of statistical analysis have shown a statistically significant difference between the two groups of participants on all variables of the VFI survey. The results suggest that the Croatian version of the VFI survey has successfully differentiated the two groups of participants, which confirms the initial research hypothesis. Additionally, the coefficient of internal consistency establishes a high internal reliability between items. Given the obtained results, further work on the Croatian version of the survey is suggested, both testing validity and testing on a larger sample. Once established, such a reliable and valid survey is quite welcome in the field of speech language pathology focused on vocal disorders, as it could then be qualitatively used in different clinical conditions for the identification of individuals with vocal fatigue, for estimating symptoms prior to administering therapy, as well as measuring recovery after therapy