Background: The effects of environmental noise on sleep are of great interest to public health. Numerous studies have been conducted to investigate these effects; however, these previous studies applied existing sound-level statistics that were not based on neurophysiology. Aims: This study aimed to develop a new night-time noise index based on neurophysiology and epidemiology. Methods: First, we derived a formula for predicting the noise effects on sleep based on a neurophysiological model of brainstem sleep regulation, where awakening was associated with greater electrical potentials in the brainstem. Second, we investigated the noise effects on sleep using the results of an epidemiological study conducted in the vicinity of the Kadena military airfield in Okinawa, Japan. Thirty volunteers participated in the study. Vibrations of whole-body movements were recorded using sheet-shaped sleep monitors for 26 consecutive nights. The onset of motility, which was defined by monitor vibrations, was used to index awakening reactions. Results: Our statistical model could properly predict the fluctuating risk of motility onset. The new index, which is the mean of the sound level above 60 dB, can be successfully used, irrespective of the duration of noise exposure. Additionally, it out-performed existing event-related noise indices. Conclusions: We derived a new night-time noise index for evaluating the noise effects on sleep. To our knowledge, this is the first study to explain the noise effects on sleep with the consideration of neurophysiology and epidemiology.

Context: The aim of this study was to verify the contributing effect in the cases of combined road traffic noise and railroad traffic noise on total noise annoyance. Materials and Methods: After opening the four-track railway of the Lower Inn Valley Route in Austria, an evaluation study was conducted by an interview survey (n=1003). The data of this survey included answers on annoyance caused by railroad, road traffic noise and total annoyance as well as self-evaluated noise sensitivity. Results: When annoyance is only related to one of these sources, a 10% share of highly annoyed persons was observed at 59 dB for road noise and 60 dB for railroad noise. The annoyance model including both noise sources with a coefficient of 0.145 for road noise, 0.034 for railroad noise and 0.431 for noise sensitivity (all p-values < 0.01) showed a regression coefficient R² of 0.299. The presence of road background noise did not influence the annoyance on railway noise. Conclusion: The combined influence of road and railway noise showed an increase of total annoyance.

Introduction: As part of an effort to enhance the efficiency of workers, experiments relating to three types of noise exposure were conducted. Previous studies have proved that pink noise can cause a brain wave to reach a lower potential. In this study, we utilized physical methods, in cognitive experiments, to understand the impacts that three colour noises have on working efficiency. Subjects and Methods: All 22 participants were exposed to a sound environment of quiet, red, pink and white noises respectively. After a laboratory experiment, details of psychomotor speed, continuous performance, executive function and working memory were recorded. Results: Red, pink and white noises were significantly positive in comparison with the quiet environment of the psychomotor speed test. As for the continuous performance test, pink noise gave the only significantly positive result. Red, pink and white noise resulted in a better executive function test. Red and pink noise showed significantly positive improvement, while white noise was significantly positive in comparison with the quiet environment of the working memory test. In addition, the results from the comfort questionnaires showed that red and pink noise increase the possibility of better judgment, implementation, and overall environment. Conclusion: At present time, it is considered that noise has negative effects on hearing and health. However, experimental results show that certain noise can enhance environmental comfort. It is feasible, in the future, to use knowledge of colour noises to improve productivity in a workplace with a healthy environment.

Introduction: Hospitals are categorized under silent zone, but noise pollution in this setup is inevitable. The noise in hospitals may have adverse effects on the patients, caregivers and professionals working in hospitals. Aim: The aim of the study was to determine awareness of public regarding noise pollution in hospitals, its health effects and mitigation measures. Method: The present study was an internet-based questionnaire survey. The questionnaire consisted of a common Section-I for all participants and an additional Section-II for participants of the study who were Audiologists. Descriptive statistical analysis was done on the acquired data. Results: 174 completed questionnaires were received and analysed, out of which 108 were general public and 66 were Audiologists. The data analysis revealed that the public is aware of the presence of noise in hospitals, some of its overt health effects and measures that can be taken to control the noise pollution in hospitals. Only 22.7% Audiologists who participated in the study were aware of the more technical aspects like permissible noise level in hospitals and their response was similar to that of the general public. Conclusion: Though the public is aware of some of the basic facts related to noise in hospitals, there is a need to create public awareness and to train Audiologists regarding hearing conservation program in hospital setups.