Perceptual-auditory and Acoustic Analysis of Air Traffic Controllers' Voices Pre- and Postshift.

OBJECTIVE: To characterize the vocal quality and acoustic parameters of voices of air traffic controllers (ATCs) without any vocal complaints before and after a shift.

METHOD: The voices of a group of 45 ATCs were recorded before and after a 2-hour shift, regardless of their operational position or number of previously worked shifts; both genders were included, participants had a mean age of 25 years, and they had a mean length of occupational experience of 4 years and 2 months. Each of these professionals was recorded phonating a sustained /a/ vowel and counting from 1 to 20, and the recordings were acoustically analyzed using the Praat software. A perceptual-auditory analysis of the recordings was then performed by three speech therapists specializing in voice, who evaluated the characteristics of each emission using a visual analog scale (VAS). The acoustic analysis was performed on the sustained /a/ vowel. The measures of intensity; frequency; maximum phonation time (MPT); and the first, second, third, and fourth formants were considered in this analysis.

RESULTS: There were no significant differences between the random pre- and postshift samples, either in the acoustic or in the perceptual-auditory analysis. The perceptual-auditory analysis revealed that 44% (n = 20) of ATCs showed alterations in vocal quality during the sustained /a/ vowel emission, and this dysphonia was also observed in connected speech in 25% (n = 5) of this group.

CONCLUSION: Perceptual-auditory analysis of the /a/ vowel revealed that a high percentage of ATCs had vocal alterations (44%), even among a group of subjects without vocal complaints.