Agnosia in dementia is the loss of ability to recognize and understand information from the 5 senses of sight, hearing, touch, taste, and smell. Read on to learn more about this loss, how it affects the daily experiences of someone who has dementia, and draw on tips on how to help someone with these losses.
What is agnosia?
Imagine not being able to recognize or understand information coming from your five senses. This loss of ability is technically known as agnosia.
Faces, objects, places, sounds, voices, odours, or tastes are often perceived but not recognized due to a disconnection between the senses and memory. This disconnection may lead to problems with personal interactions, sensory misinterpretations, safety issues and/or responsive behaviours.
Deficits of sense recognition in dementia may also be experienced in more than one of the senses such as having impaired recognition in both smelling and tasting.
Visual agnosia (seeing): “I see him, but I don’t know him”
Visual agnosia is the most common and better understood agnosia. Visual agnosia involves loss of recognition of faces, objects, even the person’s environment around the person. Forgetting who you are seems to cause the most distress for the person with dementia and family caregivers. What follows are some examples, with tips on how to help manage this loss:
Protective reactions can happen when care involves the use of objects no longer familiar (e.g. Mom facing resistance trying to help Dad brush his teeth)
Tip: Demonstrate the use of an object (such as toothbrush or face cloth) prior to handing it to the person or engaging with other personal care like bathing.
Mirrors and television
The person may no longer recognize their own reflected image in the mirror and may even enjoy talking to their reflection. On the other hand, the person may not feel safe and be frightened if he thinks the image in the mirror is an intruder that suddenly showed up
Tip: It may be a good idea to remove, reverse of cover up the mirror if the reflected image is disturbing to the person
A person may also engage with people or events on TV believing they are real.
Tip: Turn off the TV when upsetting programs are on. Someone with dementia may think the people or events are real and happening in the room.
A loss of recognition of family and others in the time they came into the person’s life (e.g., grandchildren are forgotten first)
Tip: Displaying and labelling pictures of family and friends can help cue the person to people in the photos without making them guess.
Perceiving a family member as a stranger (e.g., a son becomes an imposter)
Tip: Make it clear who you are when interacting with the person with dementia. For example, “Hi Mom, it’s me John; your son. I’m here to visit with you today.” You may probably have to say this more than once to reassure Mom or even consider leaving if your presence is making her uncomfortable as she may not recognize you.
A belief that the person is much younger than their actual age (e.g., a spouse confused over why they have an “older” spouse in their home)
Tip: Provide reassurance that you are the person’s spouse and are someone who cares and is rightly there to help and support them.
“Inappropriate” touches of affection due to misidentification (e.g., Dad mistakes his adult daughter as his wife and rubs her thigh)
Tip: Inappropriate touching may be caused not only by changes in the brain but by a need to feel intimacy or touch, needing comfort, or being bored. Distract the person and redirect to a positive activity. To distract, ask a question, turn on the TV, or offer something to eat or drink. To redirect, play music they enjoy, go outside for a walk, or bring out a favourite hobby.
Auditory agnosia (hearing): “I can hear it but I don’t recognize the sound”
Auditory agnosia is a form of agnosia where the person lacks the ability to recognize or differentiate between sounds. This deficit can be seen in environmental sounds, spoken words and music (amusia). This is where the ears and the brain do not work well together even though normal hearing is intact. A recent study suggests that an interaction between peripheral hearing loss and physical changes in the brain produces problems with environmental sound recognition. For instance, a cat meowing may be thought to be a crying baby.
Strategy to deal with auditory agnosia
The relationship between hearing and dementia is complex. According to the 2020 Lance report on risk factors, untreated hearing loss in midlife remains the largest modifiable risk factor of dementia. The report further recommends the use of hearing aids as a way to protect against cognitive decline.
Tactile agnosia (touch): “I am not sure what this feels like”
Whenever we retrieve keys from the bottom of a pocket or purse or awake at night to switch on a lamp or answer a phone, we identify these objects as distinct from other objects because of touch. Tactile agnosia (also known as somatosensory agnosia) is characterized by the loss of ability to recognize objects by touch. People find it difficult to recognize objects by touch based on its texture, size, and weight. However, some may be able to describe it verbally or recognize the same kind of objects from pictures or drawings.
How to deal with tactile agnosia
The person uses another sense to compensate for tactile agnosia. For example, a person holding a ball with tactile agnosia would not be able to identify the ball by touch alone without looking at it. When the person is able to see the ball, the more likely they are to name the object.
Taste: “I don’t know what it tastes like, maybe sweet?”
There are five basic tastes that the tongue is sensitive to: bitter (coffee, cocoa), sweet (sugar, candy), salty (salt), sour (lemon, yogourt) and umami (tomatoes, cheese, mushrooms). Various studies have investigated the taste function in persons with dementia. Researchers found that persons with dementia had trouble identifying flavors, appeared to have lost the ability to remember tastes or one taste was more prevalent than other tastes for example, sweet tastes. When taste recognition (also known as gustatory agnosia,) is lost, it may show up as changes in appetite, food preferences and/or eating behaviours.
Changing tastes can be a challenge for the caregiver. There great tips and hints that can help the person with dementia adapt to the changes in their eating and drinking abilities. Why not conduct your own informal taste test to determine what, if any, foods and drinks your family member still are able to taste and enjoy. Make a list of those foods and keep it updated.
Ofactory agnosia (smell): “I can still smell, but can’t tell you what I smell”
Olfactory agnosia is the inability to classify, contrast, or identify odour sensations verbally. Even though the ability to distinguish between smells may be normal, impaired odour perception and identification happens. For example, your Mom is adamant on wearing a smelly dress and eating spoiled food. She gets quite upset when you bring the bad smells to her attention and tell her what she should do. Mom may have olfactory agnosia as a cognitive impairment.
How to approach olfactory agnosia
- To comfort Mom in this situation, it’s all about the approach. Avoid confronting Mom or trying to convince her she needs to change her smelly clothes and throw away her food. Instead of telling, ask her: “Hey Mom, how about you put on this pretty dress, I can help. I’ll even make us some breakfast” With this alternative approach, there is no mention that the dress is dirty and smelly. Additionally, inviting her to breakfast may distract her from wanting the spoiled food.
- For a more fun activity, create an aromatherapy kit and enjoy sharing the smells of essential oils with your family member.
We have looked at how the brain and the senses can be affected in dementia by examining agnosia. Use these supportive strategies to help you and the person you care for adapt to losses of recognition.
Do you have any caregiving experiences to share about loss of recognition?