Voice Therapy Relating To Voice Disorders Arising In the Teaching Profession - Essay Example

Introduction For teachers, their voice is their primary tool. There is a frequent need for them to speak in a loud voice for prolonged periods of time, with little rest for recovery. Voice disorders are therefore, a frequent occupational hazard for teachers. Although the true prevalence of voice disorders in teachers is undetermined, the prevalence of voice disorders among teachers at a specific time varies from 4.4% to 90%, and they constitute about 5.2% to 20% of clinical cases in voice clinics (Roy et al, 2004). Therefore there is an urgent need for voice therapy for teachers. This essay is a critical evaluation of various therapies related to voice disorders for teachers. Review of literature One of the main guiding principles for many voice therapies has been to limit or reduce a patient’s vibration dose (i.e., vocal load). One treatment method to reduce vibration dose is to provide the teacher with an electronic voice amplification (VA), which can be used in the classroom (Roy et al., 2003). By amplifying the voice, the vocal load on the larynx is reduced. Consequently, the degree of tissue injury due to collision and shearing forces is lessened, and ultimately, an improvement in voice quality results (Roy et al., 2003). Roy et al., 2002 conducted a randomized clinical trial and combined patient-based treatment outcome measures with acoustic analysis to evaluate the effectiveness of two treatment programs: VA using the ChatterVox portable voice amplifier and vocal hygiene (VH). Teachers with voice disorders were randomly assigned to one of three groups: VA using the ChatterVox portable voice amplifier, vocal hygiene (VH), and a control group. All the teachers completed the Voice Handicap Index (VHI) before and after a 6-week treatment phase. Comparisons before and after treatment revealed that significant reductions on mean VHI scores, voice severity self-ratings, and the acoustic measures of percent jitter and shimmer, were achieved only by the amplification group. This study, therefore, provided an objective evidence to support the efficacy of VA. Another treatment strategy to reduce vibration dose is to either use the voice so as to cause less trauma to the vocal fold tissue and/or to systematically exercise the voice. There are two voice therapy approaches following this method: vocal function exercises (VFEs) and resonant/resonance voice therapy (RT) (Roy et al., 2003). By following a program of systematic exercise (maximum vowel prolongations and pitch glides using specific pitch and phonetic contexts), practiced at home, VFEs supposedly strengthens and rebalances the subsystems involved in voice production (i.e., respiration, phonation, and resonance) (Roy et al., 2003). The basic principle underlying the third treatment, known as respiratory muscle training (RMT) is that compensatory laryngeal hyperfunction can occur when the respiratory pump provides an ineffective voice drive (Roy et al., 2003). This vocal hyperfunction leads to tissue injury and voice change. RMT improves the strength of the expiratory muscles and increases their ability to generate expiratory pressures (Roy et al., 2003). This lessens the burden on the larynx, with subsequent reduction in the compensatory laryngeal hyperfunction and reduced tissue trauma (Roy et al., 2003). Although VA, RT, and RMT are similar in the sense that they aim to reduce the harmful effects of vibration overdose (directly or indirectly), conceptual and procedural differences exist. While in VA, vocal loudness is the main factor that is modified, amplification does not require much of lifestyle/behavioral changes and primarily aims at voice preservation or restoration without voice restriction. RT, on the other hand, aims at teaching the patient a new default neuromuscular pattern for voice production (Roy et al., 2003). In RMT, the main focus is to improve the respiratory drive for voice production without any direct integration of phonation into the therapy (Roy et al., 2003). Roy et al., 2003, conducted a randomized clinical trial using patient-based treatment outcome measures to evaluate the effectiveness of these three treatment programs. The subjects were 64 teachers with voice disorders. They were randomly assigned to one of the three treatment groups: voice amplification using the ChatterVox portable amplifier (VA; n = 25), resonance therapy (RT; n =19), and respiratory muscle training (RMT; n = 20). All completed the Voice Handicap Index (VHI) before and after a 6-week treatment phase. Intention-to-treat and as-treated analyses revealed that only the VA and RT groups reported significant reductions in mean VHI scores and in voice severity self-ratings following treatment. A post-treatment questionnaire regarding the perceived benefits of treatment showed that teachers in the VA group noticed more overall voice improvement, greater vocal clarity, and greater ease of speaking and singing voice following treatment, when compared to RT and RMT. These results confirms the efficacy of VA observed in previous studies and gives new evidence that RT could be an effective alternative treatment for voice disorders in teachers. Since VA is associated with good efficacy, high compliance rates, and low cost associated with portable VA, it can be considered as the first modality; if required, VA can be supplemented with RT (and/or VFE) (Roy et al., 2003). It is well established that following certain vocal behaviors and patterns, lifestyle, and diet choices can either be helpful or harmful to the vocal fold tissue, and consequently, the voice production. This emphasizes the importance of proper care of vocal fold tissue. Vocal hygiene (VH) is one treatment modality, which requires the patient to eliminate potentially harmful behaviors and substitute it with more vocally hygienic practices, in order to preserve or restore normal voice (Roy, et al., 2001). In general, VH programs includes instructions regarding: the amount and type of voice use, vocal behaviors that are phonotraumatic, and a discussion regarding lifestyle and diet factors that can support or interfere with a healthy voice (Roy, et al., 2001). A second voice therapy approach is vocal function exercises (VFE). By means of a program of systematic exercise practiced at home the subsystems involved in voice production (i.e., respiration, phonation, and resonance) are supposedly strengthened and rebalanced (Roy, et al., 2001). Roy, et al., 2001, aimed to assess the effects of VH and VFE approaches in 58 teachers with voice problems. The teachers were randomly assigned to one of three groups: vocal hygiene (VH, n = 20), vocal function exercises (VFE, n = 19), and a non-treatment control group (CON, n = 19). All completed the Voice Handicap Index (VHI) before and following a 6-week treatment phase, as well as post-treatment questionnaire on the perceived benefits of treatment. The VFE group reported significant reduction in mean VHI scores, more overall voice improvement, and greater ease and clarity in their speaking and singing voice after treatment, when compared to the other two groups. This result suggests that VFE could be considered as an alternative or adjunct to vocal hygiene programs (Roy, et al., 2001). Increased sound pressure levels (SPLs) of voice can lead to various vocal complications like vocal fatigue, loss of voice, hoarseness, and/or throat pain. Christine et al., 1999, conducted a study to determine the effect of sound-field frequency modulation (FM) amplification on decreasing the sound pressure level (SPL) of voice. The subjects included 10 teachers without any history of voice problems or pathology, self-reported hearing loss, articulatory or voice difficulties or upper respiratory illness at the time of the study. All testing was conducted in an unoccupied classroom and the subjects had no knowledge of the purpose of the testing. They were asked to deliver a 15-minute lecture on a topic of their choice. Two loudspeakers located on both sides of the subject produced a multitalker babble and simulated an occupied classroom. A single speaker classroom amplification system was used as the sound-field FM amplification unit, adjusted to produce an average 8-dB to 10-dB increase in speaker SPL. In order to obtain a voice sample to measure SPL in dB (A), each speaker was asked to read a short unamplified passage prior to their talk. Data analysis of the middle 2 minutes of speech (out of the total 15-minute lecture) was used. The results showed that by using the sound-field FM amplification, a significant 2.42-dB decrease in SPL is possible. This suggests that the speed of glottal closure or the glottal area could have been modified, which may be beneficial in reducing vocal fold hyperadduction and irritation. From this study, it is clear that sound-field amplification is an effective method for reducing the SPL of a teachers voice. Discussion A critical review of the studies reveals that as a common factor in most studies (Roy, et al., 2001; Roy et al., 2002; Roy et al., 2003), the exact nature of the voice disturbance (including the presence, type, and severity of vocal fold pathology) was not mentioned. It is possible that certain types of voice disorders or voice pathologies respond better to certain types of treatment. This could have favored certain types of treatment more than the others. Most of the studies had a small sample size. A large sample size is needed to provide a representative group size and also enables to compare the efficacy of two or more treatment methods. Small numbers may have an impact on the power of statistical analysis (Polgar& Thomas, 2000.) Roy, et al., 2001, assessed the effects of VH and VFE and found that the VFE group had a significant reduction in mean VHI scores, more overall voice improvement, and greater ease and clarity in their speaking and singing voice after treatment. There is a possibility that clinicians received more training in the VFE program, leading to an inadvertent bias to favor VFE. This bias could have been passed on to the subjects of the study. At the same time, it must be said that this bias alone cannot explain the treatment outcome favoring VFE. VH treatment generally also includes activities to establish, carry forward and maintain benefits of the program, like practice of specific activities at home (Kent, 2004). The non-inclusion of such practices in this study could be one reason why the VH program was ineffective in this study. VH program also needs time to be effective (Chan, 1994); the 6-week in this study was too short for positive effects to be seen. Similarly, Roy et al., 2002 analyzed the efficacy of VA using the ChatterVox portable voice amplifier and vocal hygiene (VH). The results favored VA. As mentioned earlier, the non-inclusion of activities to establish, carry forward and maintain benefits of the program could have made VH ineffective in the study. Roy et al., 2003, evaluate the effectiveness of VA, RT, and RMT. The VA and RT groups showed the best benefits. The authors acknowledge that in the case of the RT group, there is the possibility that some of the subjects could have dropped out because they assumed that sufficient benefit was not obtained from the treatment. The results could have been biased in favor of the RT group due to the elimination of a “subset of nonresponders.” Even though the main purpose of intention-to-treat analysis is to prevent against such a bias, the authors could not collect follow-up data on 5 of the RT participants who dropped out. Christine et al., 1999, showed that sound-field amplification is an effective method for reducing the SPL of a teachers voice but they could not effectively identify the mechanisms responsible for the reductions in SPL. Conclusion An analysis of the various studies show that therapy methods like vocal function exercises (VFE), voice amplification (VA), resonant/resonance voice therapy (RT) and sound-field amplification, are more effective for teachers with voice disorders, although these findings must be interpreted against the backdrop of possible methodological flaws in the studies. Although no one method has been shown to be the most beneficial, any of these methods could be tried first. It is recommended that future studies include pretreatment laryngostroboscopic examinations to know the exact nature of the voice disturbance and to confirm the laryngeal pathology before commencing the study. Future studies should also attempt to include larger sample sizes to enable randomization, increase the statistical power and reduce the bias due to dropouts. References Chan, RW (1994). Does the voice improve with vocal hygiene education? A study of some instrumental voice measures in a group of kindergarden teachers. Journal of Voice, 8, 279- 281. Kent, RD, 2004. The Mit Encyclopedia of Communication Disorders. MIT Press. p. 55-56.  Polgar, S and Thomas, SA (2000). Introduction to research in the health sciences.  4th ed. Edinburgh, Churchill Livingstone; 22, p.278. Roy, N, Gray, SD, Simon, M, Dove, H, Corbin-Lewis, K, Stemple, JC (2001). An Evaluation of the Effects of Two Treatment Approaches for Teachers With Voice Disorders: A Prospective Randomized Clinical Trial. Journal of Speech, Language, and Hearing Research, 44, 286– 296. Roy, N, Weinrich B, Gray, SD, Tanner, K, Toledo, SW, Dove, H, Corbin-Lewis, K, Stemple, JC (2002). Voice Amplification Versus Vocal Hygiene Instruction for Teachers With Voice Disorders: A Treatment Outcomes Study. Journal of Speech, Language, and Hearing Research, 45, 625-638. Roy, N, Weinrich B, Gray, SD, Stemple JC, Sapienza CM (2003). Three Treatments for Teachers With Voice Disorders: A Randomized Clinical Trial. Journal of Speech Language and Hearing Research, 46, 670–688. Roy, N, Merrill, RM, Thibeault, S, Parsa, RA, Gray, SD, Smith, EM (2004). Prevalence of Voice Disorders in Teachers and the General Population. Journal of Speech, Language, and Hearing Research, 47, 281–293. Sapienza, CM, Crandell, CC, Curtis, B (1999). Effects of Sound-Field Frequency Modulation Amplification on Reducing Teachers Sound Pressure Level in the Classroom. Journal of Voice, 13 (3), 375-381. Read More