Introduction:
Due to the energy and strain involved in providing oral instruction and education, teachers experience more voice problems than the general population (Calas, Verhulst, Locoq, Dalleas, & Seilean, 1989; Gotaas & Starr, 1993). Recent studies have demonstrated that prolonged voice use affects acoustic vocal parameters, often results in vocal fatigue, and may change vocal fold appearance and glottic closure patterns. In addition to excessive vocal use, teachers are considered to be at high-risk for vocal complaints because of increased speaking volume associated with background noise (Sapienza, Crandell, & Curtis, 1999).
In an effort to reduce this occupational health hazard, elementary and secondary schools have been using sound field amplification. Sound field (SF) amplification is a technology similar to high fidelity public address systems, whereby the speaker wears a microphone and his or her voice is amplified and transmitted throughout the classroom (or sound field). SF amplification has been shown to have positive effects on student learning (e.g., Rosenberg et al., 1999). However, little information has been collected regarding the effects of amplification on the vocal health of the classroom instructor. Although it has been shown that using SF amplification reduces pressure levels in speaking (Sapienza et al., 1999), it has not been determined if the use of SF amplification also results in changes in other vocal characteristics.
The purpose of this pilot study was to assess vocal characteristic information obtained from a classroom instructor in two conditions: with and without SF amplification. It was hypothesized that changes in jitter, shimmer, and harmonic-to-noise (H/N) ratio would be less when the teacher's voice was amplified compared to the nonamplified condition.