Effects of Occupational Risk Factors on Subjective Vocal Aerodynamic Measures in Teachers

Aerodynamics, vital to voice production forms an important correlate of voice. The study aimed to compare subjective vocal aerodynamic measures in teachers and nonteachers and verify the effects of a few known occupational risk factors on the voice of teachers. Group 1 consisted 264 female and 42 male teachers, teaching languages and/or core subjects for a minimum of 5 years, between 30 and 45 years from the local schools of the city and surrounding nine taluks. Group 2 had 100 female and 33 male nonteachers aged 30-45 years. Audio-recordings were done individually during the midweek and in the middle of the day in a quiet environment at schools (school library) using portable digital audio recorder. Tasks: (a) Maximum Phonation time (MPT): maximum sustained productions of vowels /a/, /i/, /u/ and fricatives /s/, /z/ at comfortable pitch and loudness were noted in seconds, (b) s/z ratio computed from phonations of /s/ and /z/ sounds, and (c) Counts  per Breath (CPB): counting of maximum numbers either in Kannada or English languages in a single breath. Results confirmed statistically significant increased mean values for all the measured parameters in male compared to the female participants in both groups. However, Nonteachers showed better results in almost all measured parameters compared to the teachers. Effects of known ooccupational risk factors showed mixed results and the details are discussed.