Effects of Chemical Irritants on Voice and Subsytems: an Acoustic Analysis

Abstract

Good voice quality is always vital for all individual at their occupation and in their environment to accomplish communication act. Many individuals due to their occupation are at reater risk of developing voice problems and other subsystem problems. The present study investigates the long term effect of irritants on voice quality and other subsystem function. Two groups of participants were participated in the present study. Experimental group had 43 participants (mean age- 43.56 years) who were working in a latex manufacturing factory and had a minimum experience of 10 years. Control group consisted of forty three individuals (mean age- 40.5years). Subjects performed monologue, s/z ratio, phonation duration of /a/, /i/, /u/ and reading meaningful words which included /a/, /i/, and /u/ in a VCV context. Praat software was used to analyze live voice acoustically with sampling frequency 44 kHz. A stop watch was also used to measure the phonation duration and s/z ratio. Paired sample t- test was carried out and it showed that participants in the experimental group showed significantly lower values for F0, SFF and jitter indicating an affected phonatory system. This was further confirmed by significantly short MPD values in experimental group. Result confirms that exposure to irritants for a longer time will result in vocal pathologies. Effects of irritants on voice can have significant impact on individual voice which in turn causes various pathologies in larynx and other sub system. This will have direct impact on occupation and social life. The present results will help speech language pathologist to provide good vocal hygiene measures and to reduce exposure time to irritants and also to monitor the effect of therapy for this kind of voice abnormalities.