Training outcome in future professional voice users after 18 months of voice training

The goal of this study is to define the long-term influence of vocal hygiene education and the effectiveness of voice training in 46 students. Half of the subjects, called the trained group (n = 23), received vocal hygiene education during 1 school year and voice training during 2 school years (18 months). The other half, also 23 subjects, received neither vocal hygiene education nor voice training as such (called the untrained group). The voice training is made up of technical workshops (30 h a year in groups of 5-8 subjects) and vocal coaching in the radio and drama projects (30 h whole class). In the lectures (30 h) a theoretical background on breathing, articulation, voicing and vocal hygiene was discussed. A multidimensional test battery containing the GRBAS scale, videolaryngostroboscopy, maximum phonation time, jitter, lowest intensity, highest frequency, Dysphonia Severity Index (DSI) and Voice Handicap Index (VHI) was applied before and after 18 months to evaluate the effect of voice training over time. A questionnaire on daily habits was presented before the lectures, and after 18 months to detect the long-term effect of the lectures. The objectively measured voice quality (DSI) of the trained group improved significantly over time (p < 0.001) due to training (p = 0.008), which was not the case in the untrained group. The self-assessed VHI, on the other hand, changed over time (p < 0.001) in both groups. For the trained group the VHI changed from 18.4 to 14.4 and in the untrained group from 20.1 to 15.3. It is important to note that the VHI scores of both groups remained high. The interpretation of the results of the daily habit questionnaire is disturbing: the initial high degree of smoking, vocal abuse, stress and late meals was not influenced by the lectures or training and remained high. This study proves the positive outcome and emphasizes the need for a well-organized voice training program in future professional voice users. However, the lectures and training on vocal hygiene failed to improve voice-conserving habits.