Occupational voice disorders: an analysis of diagnoses made and certificates issued in 1999-2004

It has been decided to identify the most frequent diseases of the larynx in people occupationally exposed to a considerable voice load and to assess the feasibility of using videostroboscopy to diagnose voice disorders and their organic effects in order to improve the reliability of certification of occupational vocal organ diseases as well as to evaluate the functioning of new regulations on diagnosing and certifying occupational vocal organ diseases and to assay the conformity of clinical diagnoses made at voivodeship (provincial) centers (level I) with those made at scientific research institutes (level II).

The study involved an analysis of 1261 cases (1042 women and 219 men) with the vocal organ disorders referred to the ENT Unit, Nofer Institute of Occupational Medicine, Lódź, by voivodeship centers during 1999-2004 for consultation or under the appeal procedure (if applicants were denied the right to be included in the category of patients with occupational disease of the vocal organ). The majority of the patients (65.7%) were primary school teachers, and those aged 51-60 years made 54.8%. Laryngological, phoniatric and videostroboscopic examinations, when necessary, supplemented with other testing procedures (paranasal sinus imaging, allergenic tests) were taken to assess the clinical state of the patients.

As a result of these comprehensive examinations, organic changes in the larynx were detected in 161 (12.7%) cases, including 139 (11.0%) women and 22 (1.7%) men. According to current diagnostic/certifying criteria those pathologies could be classified into the category of occupational disease of the vocal organ. Paresis of vocal folds due to the insufficiency of vocal fold adductor and tensor muscles with permanent dysphonia was found in 97 (7.6%) patients, vocal nodules in 53 (4.2%) and secondary hypertrophy changes in vocal folds in 11 (0.87%) patients. The most frequent reasons for excluding the occupational etiology of the disease were functional disorders of the voice observed in 82.3% of patients in the form of hyperfunctional dysphonia (64.3%), hypofunctional dysphonia (17.0%) and dysfunctional dysphonia (about 1.0%). In 9.0% of patients, the functional disorders of the voice were accompanied by organic changes in the larynx caused by non-occupational factors.

The analysis showed that due to new Polish regulations, the number of certified occupational disease of the vocal organ was reduced; videostroboscopic tests proved to be a very helpful tool for discriminating between the functional and organic disorders of the vocal organ; and good agreement between clinical diagnoses issued at both levels (I and II) was also revealed.