Poor acoustics in a building can have a detrimental impact on people with dementia. Here we look at some of the effects of noise and how the sound environment can be improved.
How dementia and ageing affects our hearing
As we become older, our hearing is often affected as part of the ageing process and we lose the ability to hear high frequency sounds. Childen can typically hear or sense sounds at 20,000 Hz, whereas many people aged 85 cannot hear 8,000 Hz and so have lost a huge part of their range of hearing. In a noisy environment it is difficult to pick out speech and understand conversation; this is isolating, increases anxiety and can become distressing.
For many people with dementia the ability to filter sound disapears. Sound is often experienced as a cocophony of constant background noise to which people are extremely sensitive. Noise has been shown to increase stress levels, anxiety, confusion, blood pressure, heart rate and fatigue. In addition people with Alzheimer’s disease can experience perceptual problems, which means they can misinterpret some things they see or hear.
However we must remember that not all sound is “bad”; whilst a recent study found a link between high noise levels and ‘unwanted behaviour’ in people with dementia, pleasant sounds were found to be ‘positively stimulating’ It concluded that good acoustics should be ‘one of the key architectural efforts in care environments for people with dementia.’
Sounds of nature are often felt to be calming, music is used to aid memory and positively affect mood. Ordinary day to day sounds can be used to gives clues to events for example the sound of laying the table reminds people that lunch is going to be served.