Detecting inaudible vocal organ changes through glottal inverse filtering.

The aim of this study was to investigate if there were objective quantities extracted from the speech pressure waveforms that underlay inaudible changes in the symptoms of the vocal organ. This was done through analyzing 180 voice samples obtained from nine subjects (five females and four males) before and after exposure to a placebo substance (lactose) and an organic dust substance. Acoustical analysis of the voice samples was achieved by using glottal inverse filtering. Results showed that the values of primary open quotient and primary speed quotient changed significantly (P<0.05) as did the amplitude quotient (P<0.01). Exposure to lactose resulted in significant changes of secondary open quotient (P<0.05) but opposite to effects found for exposure to organic dust. Modeling of the vocal tract into cross-sectional planes revealed that the immediate plane above the vocal folds correlates inversely with the feeling that voice is tense, or feeling the need to make an effort when speaking in addition having a feeling of shortness of breath or the need to gasp for air. Such results may point to acoustically detected subclinical changes in the vocal organ that the subject him/herself feels while they remain perceptually undetected by others.

Pilot study on acute voice and throat symptoms related to exposure to organic dust: preliminary findings from a provocation test.

The aim of this pilot research was to investigate acute voice and throat symptoms related to organic dust exposure among nine subjects with suspected occupational rhinitis or asthma. Subjective voice and throat symptoms were recorded before and after an occupational exposure test. In addition, the study included perceptual assessment of subjects' voice samples recorded before and after the exposure tests. The results showed a number of (statistically) significant voice and throat changes in symptoms based on subjects' own assessments. These symptoms included a hoarse, husky, or tense voice, requiring an extra effort when speaking and difficulty in starting phonation (P < 0.05). Other significant symptoms included feeling of shortness of breath or the need to gasp for air and feeling that the voice is weak or that it does not resonate (P < 0.01). Such changes were not, however, detected by voice clinicians in the listening test of subjects' voice samples recorded before and after the exposure. These results suggest that the larynx reacts to organic dust with symptoms that are felt by the patient rather than heard by the voice clinician. The voice disorder in such cases is a diagnosis based on symptoms expressed by subjects.

Use of nasal provocation test in the diagnostics of occupational rhinitis.

OBJECTIVES: The purpose of the study was to evaluate the usefulness and clinical value of the nasal provocation test (NPT) with various allergens and non-IgE-mediated irritants in the diagnostics assessing occupational rhinitis. METHODS: A large number nasal provocation data from patients with suspected occupational rhinitis was evaluated retrospectively. The results of nasal provocation tests with different agents, as well as the correlation of nasal scoring to weighed mucus secretion, were analyzed. RESULTS: Altogether 507 NPTs were done in three years in 165 persons. In total, 39% of the allergen provocations (125/318) were positive. The most common positive reactions were against flours, animal epithelia, storage mites and various plants. Wood dusts, mainly through non-IgE-mediated reactions, gave 50% positive results. Positive NPTs to moulds were observed mainly in sensitized patients. Altogether, 10% of the control provocations were positive. The weighting of mucus secretion added sensitivity of NPT. CONCLUSIONS: The NPT is an essential standard tool in the diagnostics of allergic occupational rhinitis; however it needs to be evaluated in the context of the medical and work history and knowledge of sensitization. Although expensive and laborious, NPT is safe and easy for the patient. We still need reliable diagnostic tools for non-allergic work-related rhinitis.

Occupational respiratory hypersensitivity in dental personnel.

OBJECTIVE: The aim was to study the causes of respiratory hypersensitivity in dental personnel based on the statistics of the Finnish Register of Occupational Diseases (FROD; 1975-1998) and the patient material of the Finnish Institute of Occupational Health (FIOH; 1990-1998). METHODS: Details about the cases of respiratory hypersensitivity were compiled from the FROD. The occupational rhinitis diagnoses studied at the FIOH were based on work-related symptoms and a change in the status of the nasal mucosa during challenge testing; and the diagnosis of occupational asthma based on reactions in challenge testing, or on IgE positivity and peak flow monitoring at work and during days off. RESULTS: A total of 64 cases of occupational respiratory diseases (ORDs) was diagnosed in dental personnel during 1975 to 1998 according to the FROD; two cases in 1975 to 1989, and 62 in 1990 to 1998. Twenty-eight cases were of occupational asthma (18 caused by methacrylates), 28 occupational rhinitis (six caused by methacrylates), seven allergic alveolitis and one organic dust toxic syndrome (ODTS). The non-acrylate-material diagnosed in 1990-1998 at the FIOH comprised three cases of asthma and one of rhinitis caused by chloramine-T (sodium- N-chlorine- p-toluene sulphonamide); as well as one case of asthma, seven cases of rhinitis, and two cases of combined rhinitis and conjunctivitis caused by natural rubber latex (NRL). Furthermore, one case of occupational rhinitis caused by Nobetec containing colophony was diagnosed. The incidence rate (IR) of ORD increased from 0 in 1988 to a peak of 105.1 new cases per 100,000 working years in 1995. During the last observation year, i.e. 1998, the IR was 55 new cases per 100,000 workers. The IR in dental personnel was lower than in the whole working population in Finland up until 1992, but since then has been greater than in the whole population, peaking in 1995 when the IR of dental personnel was 2.55 times greater than in the whole population. CONCLUSION: The present study shows the increasing frequency of respiratory hypersensitivity among dental personnel. Besides methacrylates, important causes of respiratory hypersensitivity are NRL and chloramine-T.