One aspect of thinking affected by dementia is sensory perception. Sensory perception is the process where our brain interprets or understands information we get from our senses; sight, smell, taste, touch, and other less well-known senses like those in our joints that give feedback of where our body is moving, without having to look at our arms or legs. For some people, dementia damages the part of the brain that interprets information that comes from the senses.
For example, in posterior cortical atrophy, a type of dementia often affecting younger people, the eyesight of the person living with dementia might be normal or corrected with glasses, but their brain may have difficulty converting the signals from the eyes into a meaningful picture.
They might experience trouble with depth perception – i.e. judging how deep or far away something is. This can mean they have trouble walking up or down stairs and lose balance or have falls, especially when the colour of floor surfaces vary.
They may have trouble picking out an object from its background, particularly if it’s the same colour, there are shadows, or the background is patterned.
Erik used to set out Mary’s clothes for the day on the bed, and Mary would frequently get angry saying “it isn’t helpful when there is no underwear!” Erik would get exasperated and say, “it’s there, it is right in front of you”. An occupational therapist pointed out that Mary had difficulty ‘seeing’ her white underwear against the white sheet. Placing the clothes on the contrasting bedspread solved this issue.
They may also have difficulty interpreting visual information when there is a mirror, or reflections from wet or shiny surfaces or glare. Cherie found walking on the swirly patterned carpet at the club almost impossible as it made her giddy and needed an arm to steady her.
Perceptual changes may also affect the way people with dementia experience hearing, touch, smell and taste.
Learn from others and for more information
Dementia and Sensory Challenges is an informative booklet that provides insight into sensory and perceptual changes from people living with dementia who experience these perplexing symptoms and gives practical suggestions to help.
Photo: Solstice Hannan via Unsplash.
