Healthcare at Internoise 2022

Tomomi Yamada: Masking effect of sounds during treatment on dental drill sound

The drill is an excellent device – except for the sound! Well, we can probably all agree to that opening statement by Tomomi Yamada.  It´s human nature to respond instantaneously to frightening sounds and this sound probably affects most people! The sound is however not very loud but we find it disturbing anyhow. What if we could do something about the perceived sound and what it evokes in us?

A dental drill has an influence on the acoustic environment in a dental clinic. Sounds of dental drills are temporarily varying and have several prominent frequency components in a wide frequency range. Many patients experienced unpleasant feelings with the sound of a dental drill. In Japan, the use of dental aerosol suction devices, of which loudness levels are high, during dental treatment has increased dramatically compared with their use before the COVID-19 pandemic. In this study, the sounds emitted by dental drills and sounds related to dental aerosol suction devices were investigated and a psychoacoustic evaluation of the stimuli combining the two noises was conducted.

The average spectra of a dental drill noise and a dental suction noise used in the experiment

The present findings suggest that reducing the sound pressure level and refining the frequency characteristics of sounds emitted by dental drill considering acoustical characteristics is important for creating a comfortable sound environment in dental clinics. The results may help to improve the discomfort feeling in the dental sound environment. Thank you for that!


Arezoo Talebzadeh: Using psychoacoustic parameters to select suitable sounds to augment soundscapes for people with dementia

Sound augmentation as an environmental intervention to improve mood and cognitive behaviour has shown promising results in recent years. The same approach has a positive effect in reducing anxiety, stress, agitation and improving sleep quality in people with cognitive disabilities. People have an interest in evaluating their sound environment, both in their homes and if they reside in a care unit.

But using this method is hardly possible when designing for people with dementia, as the disease makes communication incomprehensible in most cases. Therefore, caregivers are the best sources of evaluation; their familiarity with patients and knowledge of the patients’ behaviour and psychology is crucial to evaluate the soundscape and the environment.

During the experiment in the nursing homes, caregivers evaluated the effect of specific sounds on the participants by pressing feedback buttons

Feedback evaluation by Caregivers

This research uses caregivers’ evaluation of a designed soundscape and the possible scientific way of selecting a suitable sound. By assessing the character of the sound, and its psychoacoustic respons from the patient via the caregivers’ feedback. Using feedback data and psychoacoustic parameters of sounds, a logistic regression model with a single independent variable demonstrated the chance of a positive outcome (sound) versus continuous indicator value (psychoacoustic parameter). The preliminary result revealed a possibility of sound augmentation using psychoacoustic parameters to identify favorable sounds.

All unfamiliar sounds bear risk to add to anxiety or annoyance for a patient with dementia. Care facilities are unfamiliar compared to their homes; not only the sounds but the light, the smell and the temperature. Using psychoacoustic parameters to select proper sounds for soundscape augmentation is one way of finding a suitable method for designing soundscapes in long-term care facilities and senior housing.


Claudia Lissåker: Occupational exposure to noise and myocardial infarction risk one year later in Sweden

The objective was to explore the association between occupational noise exposure and myocardial infarction (MI) one year later. This was achieved by using data from the SNOW cohort, comprised of all individuals born between 1930 and 1990 in Sweden. Including demographic, occupational, and outcome data available from 1960 until 2017.

The study included working individuals with at least one occupational code between 1985 and 2013. These were matched to a job exposure matrix in five categories (LAeq8h): 85 dB(A). MI status in the year following exposure was ascertained using the patient register. To account for time-varying occupational data, a discrete-time proportional hazards model adjusted for individual confounders. The preliminary results indicated that exposure to over 75 dB(A) of occupational is associated with a 13-21% increased risk for MI one year later!

But after adjusting for psychosocial work exposures, physical workload, exposure to vibrations, and chemical and particle exposure, noise exposure was no longer associated with an increased risk for MI. So what to make of this?  Conclusion: exposure to noise was not associated with an increased risk for MI one year later after adjusting for other work exposures among this younger, working population. Additional in-depth analyses are ongoing. So we might say that the ‘jury is still out’ on this one. However, a difference was noticed between the sexes.

Yearly number of participants with an occupational code by sex from 1985-2013


Jeppe Christensen: Distinct influence of everyday noise on cardiovascular stress

High-intensity environmental noise is known to be detrimental to cardiovascular health. However, individual differences have not been considered, and reported effects cannot be generalized to noise levels reflecting everyday life.

In this study the relationship between daily-life sound exposure and heart rate from ten individuals across three weeks are explored. Analyzed by the daily short-term covariation between changes in heart rate and sound intensity using multi-level regression and Granger analysis.

Noisy environments are harder to listen in and therefore potentially cause a stress reaction.

Strong evidence was found that everyday sound exposure is related to heart rate in all participants. Sound intensity is linearly and positively related to heart rate. While the ambient signal-to-noise ratio has a negative association to heart rate in louder environments. Across participants a distinct temporal pattern of Granger causality with stronger influence of the sound environment on heart rate from 6:00 – 16:00 hours, than for the rest of the afternoon/evening.

We propose that sound sensitivity measures represent a combination of the amount of effort asserted to listen under noisy conditions during the active periods of a day. Also the direct physiological sound-induced stress reaction. A thorough understanding of both factors is necessary to determine the full extent to which everyday noise influence long-term health. Noisy environments are harder to listen in and therefore potentially cause a stress reaction.


More Internoise 2022:

Sustainable acoustics at Internoise 2022

Improving the acoustic conditions for children with special listening needs (Adrian James)

All proceedings can be found here


Healthcare 144

Related Blog Posts