Long-term exposure to noise is being linked to an increased risk for Alzheimer’s and other forms of dementia.
“Ten decibels more daytime neighbourhood noise is associated with 36 per cent higher odds of mild cognitive impairment and 30 per cent higher odds of Alzheimer’s disease, according to a new study,” reports futurity.org.
Dementia Australia defines Alzheimer’s disease as “the most common form of dementia, affecting up to 70 per cent of all people with dementia”. It damages the brain, resulting in impaired memory, thinking and behaviour.
Study author Jennifer Weuve, associate professor of epidemiology at Boston University’s School of Public Health, says research into noise and dementia is in its early stages, but the “signals so far” suggest we should pay more attention to the possibility that noise affects cognitive risk as we age.
“If that turns out to be true, we might be able to use policy and other interventions to lower the noise levels experienced by millions of people,” she says.
Her study has tested the cognitive function of 5227 Chicago adults every three years since the 1990s. The researchers analysed the relationship between participants’ cognitive function and the noise levels in the neighbourhoods where they had lived over a 10-year period, factoring in date of birth, sex, race, education level, household income, alcohol intake, smoking status, physical activity and neighbourhood socioeconomic status.
Residential noise levels experienced by participants varied from 51 to 78 decibels, or from “the level of a relatively quiet suburban neighbourhood to that of an urban setting near a busy highway”.
Senior author Sara D. Adar, associate professor of epidemiology at the University of Michigan School of Public Health, says the study’s findings, published in the journal Alzheimer’s & Dementia, suggest that in typical urban communities “higher levels of noise may impact the brains of older adults and make it harder for them to function without assistance”.
“This is an important finding since millions of Americans are currently impacted by high levels of noise in their communities,” she says. “Although noise has not received a great deal of attention in the United States to date, there is a public health opportunity here as there are interventions that can reduce exposures both at the individual and population level.”
Low frequency noise common to urban areas is known to trigger negative physiological reactions, such as “changes to blood pressure, vertigo and breathing difficulties”, even when the noise is not audible. Most currently commercially available noise-cancelling devices and constructions focus on high frequency noise.
Assoc. Prof. Weuve says community noise level guidelines were last set in the US by its Environmental Protection Agency in the 1970s, to protect against hearing loss.
She has been granted $6 million from the National Institute on Ageing for two dementia studies, one which investigates air pollution and community noise exposure.
Britain’s Social Care Institute for Excellence says the impact that noise has on people with dementia is rarely considered in the management or design of aged care environments.
“And yet, noise that is acceptable to care staff may be particularly distressing and disorientating for a person with dementia, especially at busy times of day such as shift change-over and mealtimes.
“Of all the senses, hearing is the one that has the most significant impact on people with dementia in terms of quality of life. This is because dementia can worsen the effects of sensory changes by altering how the person perceives external stimuli, such as noise and light. As hearing is linked to balance, this also leads to a greater risk of falls either through loss of balance or through an increase in disorientation as a result of people trying to orientate themselves in an environment that is overstimulating and noisy.”
People with dementia respond better to body language or tone than to words because they have a reduced ability to understand their sensory environment. When this is combined with age-related deterioration in hearing, “people react to their environment rather than being supported or enabled by it”.
“If other senses are overloaded at the same time as hearing (such as sight, touch, smell and taste) the effect can be a dramatic change in the behaviour of a person with dementia. For this reason, care staff often identify mealtimes as being especially problematic. Research highlights the importance of appropriate background noise for maximum enjoyment at mealtimes, even for people who do not have dementia.”
The right environment for a person with dementia
When communicating with a person with dementia, try to:
- avoid competing noises, such as TV or radio
- stay still while you are talking – this makes it easier for the person with dementia to follow what you are saying
- maintain regular routines – this helps to minimise confusion and can assist communication
- keep a consistent approach – it is much less confusing for the person with dementia if everyone uses the same style of communication. Repeating the message in the same way is important for all the family and carers.
Does urban noise worry you? Are you comforted by the extent of the research dedicated to understanding Alzheimer’s and dementia?
If you enjoy our content, don’t keep it to yourself. Share our free eNews with your friends and encourage them to sign up.