Extra-auditory effects of noise exposure in school workers and preventive measures: a systematic review.

OBJECTIVE: Noise is still today one of the main causes of occupational diseases; in fact, in Italy in the three-year period 2019-2022, hearing loss represented 15% of all occupational diseases recognized by the National Institute for Insurance against Accidents at Work. The extra-auditory effects related to noise exposure also require particular attention, because they can interfere with mental activities that require concentration, memory and ability to deal with complex problems, causing sleep and learning disorders. For this reason, acoustic comfort is considered a fundamental requirement for obtaining an optimal degree of well-being in closed environments. In schools, a high degree of noise pollution not only makes it difficult for students to listen and learn, but also affects school workers. The aim of this study was to perform a systematic review of international literature and analysis of the preventive measures of extra-auditory effects among school workers. MATERIALS AND METHODS: The presentation of this systematic review is in accordance with the PRISMA statement. The methodological quality of the selected studies was assessed with specific rating tools (INSA, Newcastle Ottawa Scale, JADAD, JBI scale and AMSTAR). Only publications in English were selected. No restrictions were applied for the publication type. We excluded articles not concerned with the extra-auditory effects of noise exposure in school workers and preventive measures, findings of less academic significance, editorial articles, individual contributions, and purely descriptive studies published in scientific conferences. RESULTS: Online research indicated 4,363 references: PubMed (2,319), Scopus (1,615) and Cochrane Library (429) have been consulted; 30 studies were included in this review (5 narrative or systematic reviews and 25 original articles). Regarding the scores of narrative reviews, the INSA score showed an average and a median value of 6.5, thus indicating an intermediate/high quality of the studies. Regarding the scores of systematic reviews, the AMSTAR score showed an average of 6.7 and a median and a modal value of 6, thus indicating a high quality of the studies. The scores assigned to the original articles have an average and median value of 7 and a modal value of 6 and this demonstrates an intermediate/high quality of the studies. CONCLUSIONS: We can assume that, as it is highlighted by this study, to date these consequences are not considered at the legislative level for the protection of exposed workers. The extra-auditory effects impacting health afterward environmental noise exposure are many and widespread. Therefore, there is a need for interventions to be carried out by institutions and that the physician of the schools, during health surveillance, investigates the effects and clinical manifestations, in order to prevent disorders and deficits highlighted by our study.

[Pilot study of professional exposure and hearing functionality of orchestra musicians of a national lyric theatre]. / Studio pilota dell'esposizione professionale a rumore e della funzionalità uditiva dei musicisti di una orchestra lirica nazionale.

The sound exposure of classic orchestra musicians is not well assessed in Italy even though the protectionistic law includes all the working environments, as stated in the European Directive 2003/10/EC relative to the protection of workers against noise-induced damage. Scientific data in the literature show that the musicians are exposed to high daily personal exposure levels. These levels can systematically exceed the 85 dB(A) in the case of percussionists. In this study, preliminary results are shown relative to an experimental campaign performed in a lyric National Theatre. The aim of the study was the assessment of the risk due to high sound level in the theatre musicians and their cochlear functionality. The noise levels were measured by using wearable phonometers and multichannel sound analyzers. The signals were recorded during the whole working time in the rehearsal hall and in the fossa. The cochlear functionality was monitored before and immediately after rehearsal in a sample of volunteers by means of otoacoustic emission tests. Both TEOAE and DPOAE were measured using the ILO292 portable system. The data show that OAE-based tests can effectively discriminate between different classes of exposure. A good correlation was found between the daily exposure level and the DPOAE level.

Effect of vibration magnitude, vibration spectrum and muscle tension on apparent mass and cross axis transfer functions during whole-body vibration exposure.

Twelve seated male subjects were exposed to 15 vibration conditions to investigate the nature and mechanisms of the non-linearity in biomechanical response. Subjects were exposed to three groups of stimuli: Group A comprised three repeats of random vertical vibration at 0.5, 1.0 and 1.5 ms(-2) r.m.s. with subjects sitting in a relaxed upright posture. Group B used the same vibration stimuli as Group A, but with subjects sitting in a 'tense' posture. Group C used vibration where the vibration spectrum was dominated by either low-frequency motion (2-7 Hz), high-frequency motion (7-20 Hz) or a 1.0 ms(-2) r.m.s. sinusoid at the frequency of the second peak in apparent mass (about 10-14 Hz) added to 0.5 ms(-2) r.m.s. random vibration. In the relaxed posture, frequencies of the primary peak in apparent mass decreased with increased vibration magnitude. In the tense posture, the extent of the non-linearity was reduced. For the low-frequency dominated stimulus, the primary peak frequency was lower than that for the high-frequency dominated stimulus indicating that the frequency of the primary peak in the apparent mass is dominated by the magnitude of the vibration encompassing the peak. Cross-axis transfer functions showed peaks of about 15-20% and 5% of the magnitudes of the peaks in the apparent mass for x- and y-direction transfer functions, respectively, in the relaxed posture. In the tense posture, cross-axis transfer functions reduced in magnitude with increased vibration, likely indicating a reduced fore-aft pitching of the body with increased tension, supporting the hypothesis that pitching contributes to the non-linearity in apparent mass.

[Hand-arm vibration syndrome and upper limb disorders associated with forestry work]. / Sindrome da vibrazioni mano-braccio e patologie degli arti superiori correlate con il lavoro forestale.

BACKGROUND: Occupational exposure to hand-transmitted vibration in forestry workers is associated with an increased risk for vascular, neurological and musculo-skeletal disorders of the upper limbs. OBJECTIVES: To carry out a cross-sectional study of the hand-arm vibration syndrome and soft-tissue disorders of the upper limb in a group of forestry workers employed in the Forestry Service of the Province of Trento (Italy). In the forestry worker group, usage of anti-vibration chain-saws was intermittent over a typical work year (16 weeks/yr, on average). METHODS: To investigate vascular, neurological and musculo-skeletal disorders of the upper limbs, the forestry workers (n=159) and a control group of manual workers, unexposed to hand-transmitted vibration, employed in the same Forestry Service (n=146) underwent a structured medical interview and a complete physical examination. The clinical diagnoses of vibration-induced white finger (VWF) and carpal tunnel syndrome were made according to internationally recognised consensus criteria. Occupational exposure to hand-transmitted vibration was assessed according to the recommendations of the International Standard ISO 5349-1 (2001). RESULTS: The forestry workers showed an increased prevalence of peripheral sensory-neural disturbances (33.3%), musculo-skeletal disorders of the upper limbs (37.7%), and carpal tunnel syndrome (21.4%) compared to those observed in the control group. There was no significant difference in the prevalence ofRaynaud' sphenomenon between the forestry workers (6.3%) and the controls (4.1%). After adjustment for confounding factors (age, body mass index, tobacco and alcohol consumption), a significant association was observed between peripheral neuropathies (peripheral sensory-neural disorders, carpal tunnel syndrome) and several indices of vibration exposure such as 8-hr energy-equivalent frequency-weighted acceleration [A(8) in m/s2 r.m.s.], duration of exposure (years), and lifetime vibration dose (m2/s4 hr). An excess, although not significant, risk for VWF was observed only in the forestry workers with A(8) > or = 4 m/s2 r.m.s.. In the forestry workers, there was no significant association between VWF and sensory-neural disorders, and between VWF and carpal tunnel syndrome. This finding seems to support the hypothesis that the vascular and neurological components of the hand-arm vibration syndrome develop independently of each other. Within the forestry worker group, the variable "years of tool usage" showed the strongest association with peripheral sensory-neural symptoms, carpal tunnel syndrome, and soft-tissue disorders of the upper limbs. It is likely that in the forestry workers the variable "years of tool usage" represents an overall index of duration of exposure to several adverse ergonomic and mechanical risk factors. CONCLUSIONS: The results of this study suggest a tendency for a decrease in the occurrence of VWF among forestry workers, and this finding seems to be associated with the use of anti-vibration chain saws, the reduction of exposure duration, and the improvement of work organization. On the other hand, the forestry workers showed an increase in the occurrence of peripheral sensory neuropathies, carpal tunnel syndrome, and upper-extremity musculo-skeletal disorders. This finding seems to support the view that there is epidemiological evidence for a positive association between exposure to a combination of risk factors (segmental vibration, forcefulness, awkward posture) and the occurrence of soft-tissue disorders of the upper limb in working populations.