Survey of Voice Acoustic Parameters in Iranian Female Teachers

Objectives. Teachers are one of the professional voice users. Voice problems are common among them. Female teachers are known to have more voice problems than male ones. Furthermore, there are only few studies on the voice of Iranian female teachers. The present study investigated the acoustic parameters of voice in Iranian female teachers and compares them with nonteachers. Methods. In this cross-sectional study, 90 Iranian female elementary teachers, 30-50 years old, and 90 Iranian female nonteachers in the same age were assessed between May 2010 and October 2011. Data collection was carried out, using the Dr. Speech software (subprogram: vocal assessment Version 4.0 from Tiger Electronics) at the speech therapy clinic under a comfortable phonation. Normal voice in practitioners was judged by the perceptual evaluation by a voice therapist and indirect laryngoscopy examination by an otorhinolaryngologist. Voice characteristics were assessed with GRBAS scale. The speech sample was sustained /(a) over cap/ using habitual and constant vocal for 10 seconds. Three tokens from each subject were obtained. Then, each subject was asked to read a standard passage in Farsi. Eventually, the difference measures of F-0, jitter, shimmer, harmonic to noise ratio (HNR), and maximum of phonation time (MPT) between two groups were investigated by statistics software SPSS 19.0 (IBM corp.2010). Results. Results showed that the values of F0 were higher in teachers (210.03 Hz) than in nonteachers (194.11 Hz; P < 0.001). In addition, the values of perturbation measures were greater in teachers (jitter 0.32% and shimmer 4.63%) than those in the control group (jitter 0.22% and shimmer 3.15%; P < 0.001), but in HNR and MPT values, nonteachers showed higher levels (P < 0.001). The value of HNR in teachers was (18.84 +/- 1.56) but it was (21.3 +/- 1.73) in non-teachers and MPT value in teachers was (16.83 +/- 3.65) and in non-teachers was (22.5 +/- 5.2). Conclusions. It can be concluded that vocal overuse, abuse, or misuse during teaching over a period of time result in achievement of inadequate phonatory pattern with excessive musculoskeletal tension, and the possible result is tissue changes in teacher's voice. In addition, acoustic analysis of voice parameters for teachers may significantly contribute to the objective voice examination of this group.