Voice Quality of Choir Singers and the Effect of a Performance on the Voice.

BACKGROUND: The voice use of choir singers is understudied despite the imbalance of high vocal demands versus low vocal education, and consequently increased risk for voice problems. Also, there is a lack of information on the effects of a performance on choristers' voices. Available studies included performances of at least one hour. To date, no studies investigated the effects of a choir performance with a duration resembling vocal warm-ups. PURPOSE: The first purpose of this study was to determine the voice quality, capacities, symptoms and voice-related quality of life of choir singers. Secondly, the effect of a short choir performance, resembling warm-up duration (15 minutes), on the choristers' voices was investigated. METHODS: A randomized controlled trial was used. Thirty adult choir singers (25 women, 5 men; mean age: 32 years) were assigned randomly to an experimental group or a control group. Participants in the experimental group sung in choir for 15 minutes immediately after their pre voice assessment, whereas the control group was instructed to have standard voice use (one-on-one conversation with the investigator, no singing) across that time span. A second voice assessment was repeated afterwards. RESULTS: The choir singers showed excellent voice quality and capacities with mean scores on the Dysphonia Severity Index and Acoustic Voice Quality Index of 7.5 and 2.0, respectively. Auditory-perceptually, the mean grade score was 5/100 corresponding with a normal to mildly deviant voice quality. Patient-reported outcome measures showed mean deviant scores, indicating a considerable singing voice handicap. The choir singers seem vulnerable for stress with a high occurrence rate of 76.7% (23/30). Compared with the control group, the Dysphonia Severity Index significantly improved, whereas the self-perceived presence of vocal fatigue and complaints increased after 15 minutes of choir singing. Fundamental frequency increased in both groups, being more outspoken in the experimental group. CONCLUSIONS: Choir singers show excellent voice quality and capacities, that further improve after a short choir performance of 15 minutes. Vocal fatigue and complaints, on the other hand, already increased after that short time span. Realizing that vocal load is much higher in real-life rehearsals, competitions and performances, choristers deserve and need a qualitative voice training and a strict follow-up. Future research should focus on effective vocal warm-up and cool-down programs for this population.