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3.3.1 Prevalence of voice problems in teachers

Professionals requiring effective voice use (including actors, lawyers, singers as well as teachers) are potentially at risk of voice problems due to occupational voice use [55]. Anecdotally it is often considered that teachers experience voice problems disproportionately, as a result of their occupational voice use.

There have been a number of studies to determine the prevalence of voice problems among teachers using three primary methods:

1) Voice clinic attendance. 2) Questionnaire surveys.

3) Phoniatric examination of the body systems involved in speech production.

Between studies there was considerable variation in how, or if, voice problems were defined. This is a factor when comparing data from different studies. The findings of the studies using different methodologies are summarised in the following sections.

3.3.2 Voice clinic attendance

A number of studies in different countries analysed attendance at voice clinics by occupation. The underlying assumption is that the greater the attendance by a given occupational group, the greater the prevalence in the group as a whole. However, there may also be other possible explanations if a group is over represented.

Investigations of attendees in US and Swedish voice clinics (2001) [56] looked at the prevalence of voice problems by occupation along with the proportion of the general population who had that occupation. Based on clinical attendance teachers were 19.6% of attendees but only 4.2% of the population. Teaching was not the occupation with the highest risk factor; professional singers formed 11.5% of attendees but 0.02% of the population. The numbers of individuals who work in professions identified as high risk may have a bearing on how important this is considered by society.

Research by the Voice Care Network (1992) [20] in the UK identified that teachers made up 34% of attendees at the sampled speech therapists’ clinics, a much higher percentage than their proportion of the population.

Sapir et al. (1993) [57] suggested that teachers may be reluctant to seek medical help, with fewer than 1% of respondents having sought help. This may be due to teachers being aware of small changes to their voices but not considering these serious enough to seek help.

Other researchers have suggested that even though members of a particular profession are over represented at voice clinics, voice problems may not necessarily be greater in that occupation [58]. The impact that voice problems have on that group may be problematic and disruptive to their work. Other professions with a similar prevalence of voice problems, but for which voice problems do not interfere with critical tasks, may result in less disruption to the individuals involved and a smaller proportion seeking help [58].

One additional factor that is not always considered is the relative rate of voice problems in teachers and the general population. The prevalence of voice problems in the general population is not well established [59]; estimates include 6% experiencing significant communication effects [45], and 3-4% of a population (Australia) having voice disorders [60, 71] which is lower than the apparent prevalence in teachers.

3.3.3 Questionnaires

reported and are not normally followed up by medical examinations. Some studies used selected participant and control groups, whereas others relied on self-selection which may potentially have introduced bias.

Smith et al. in the United States (1997) [61] found that 15% of primary and secondary school teachers (n = 242) had voice problems versus 6% of a control group, and 20% of the teachers had been absent from work due to voice problems compared with 0% of the control group. This gives a 2.5 times over representation, similar to the report of 4.6 times incidence of voice problems among teachers from a voice clinic attendance study [56].

Russel et al. (1998) [59] found that 35% of teachers sampled in an Australian study reported voice issues every six months or more frequently during their career. These levels were considered significant, however, the study referred to the absence of statistics for the prevalence of voice problems in the general population referring to estimates by others [45].

A survey of secondary school teachers in England (n = 200) in 2011, found that 51% of respondents had experienced voice or throat problems in the previous two years and 17% had been absent from work as a result of these voice problems. Of these 20% had been absent for between one and four weeks [62].

3.3.4 Phoniatric examination

A robust method of identifying objective voice problems is by medical examination by a phoniatrician. Phoniatrics is the medical speciality of voice, speech, language, hearing and swallowing disorders. The expense and logistical difficulties of this approach as a research method, particularly with large sample groups, means that this approach has only been employed in a small number of studies which have generally been cross- sectional in design.

Lejska (1967) [63] undertook examinations (n = 722), finding symptoms of vocal pathology in 5.7% of female, and 1.4% of male teachers. Participants had ‘weak voices’ without vocal pathology at a rate of 16.5% for female, and 7% for male teachers.

Other research found higher rates of vocal pathology in female teachers, with two studies showing vocal nodules present in 9.7% [64] and 13% [65] of female participants. This indicated that the prevalence of vocal pathology was higher in female teachers than their male counterparts. This gender differential was not present in an equivalent (control) group of non-teachers.

The examination approach may underestimate the prevalence of voice problems as it may not include those who experience voice problems but do not present with physical pathology. Mathieson (1993) [5] indicated that at least 33% of patients who reported voice problems did not have identifiable voice pathology, emphasising that voice problems can still be significant for the sufferer irrespective of vocal pathology.

3.3.5 Prevalence summary

Despite indications in various studies that teachers have a higher risk of voice problems, the nature of the various studies and a lack of statistical controls mean that overall the link cannot be confirmed and that the evidence is not definitive. This is in line with the view of other reviews of the literature such as that carried out by Mattiske et al. in 1998 [66].

There is an argument that, irrespective of definitive evidence, the size of the teaching profession globally warrants particular attention and further investigations due to the large number of individuals potentially at risk. An elevated risk of voice problems has the potential to have substantial impacts for the teachers concerned, as well as for pupils, schools and wider society, as discussed in the following section.