3.6 Sensory and perceptual changes

One aspect of thinking that many people don’t realise can be affected by dementia is sensory perception. For some people, dementia damages the part of the brain that interprets information that comes from the senses.

For example, your eyesight might be fine (or corrected with glasses) but your brain may have difficulty converting the signals from the eyes into a meaningful picture. As a result, you might experience trouble with depth perception – i.e. judging how deep or far away something is, or you might have trouble picking out an object from its background, particularly if it’s the same colour, if there are shadows, or the background is patterned.

Erik used to set out Mary’s clothes for the day on the bed. While Mary found this helpful, she would get exasperated and tell Eric, “It isn’t helpful when there is no underwear!” Erik would get annoyed and say, “It’s there, it is right in front of you”. An occupational therapist pointed out that Mary had difficulty ‘seeing’ white clothes against the white sheet. Placing the clothes on the contrasting bedspread solved this issue.

You might 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 and needed an arm to steady her.

Perceptual changes can also affect the way you experience sound, touch, smell and taste. These changes can be quite perplexing. In the box below there is a link to a booklet written by a group of people living with dementia. They describe the types of sensory changes they experience and give ideas how to help.