Why Someone With Dementia May Reach for Something That Isn’t There

We rely on depth perception constantly, often without even realizing it.

It allows us to reach for a cup, step off a curb, sit down in a chair, climb stairs, and move confidently from one type of flooring to another.

Depth perception is our ability to see the world in three dimensions.

It helps us understand an object’s size, including its length, width, and depth, and judge how close or far away it is.

This ability depends on the eyes and brain working together. The eyes gather visual information, while the brain interprets it to estimate distance, shape, location, and how objects relate to one another in space.

How Dementia Can Affect Depth Perception

Even when people with a dementia have eyes that appear healthy, changes in the brain can interfere with the way visual information is processed.

Because dementia involves damage to brain cells and the connections between them, the areas responsible for vision and spatial awareness can also be affected.

As a result, a person may be able to see something clearly but still misinterpret what they are seeing.

Dementia and challenged eyesight often go hand in hand, because the brain plays such an important role in making sense of what the eyes see.

What Changes Decreased Depth Perception Can Look Like

1. Reaching for something at the wrong distance

   A person with dementia may reach for a cup, railing, piece of furniture, or another object that is farther away than they realize. To someone watching, it may look like they are simply grabbing at the air. But from the person’s perspective, the object may appear to be within reach.

2. Sitting too far away from the table

   Depth-perception changes can make it difficult to judge where the table is in relation to the body. A person might sit down with their chair too far from their plate and not realize there is an unusual amount of space between them and the table. A caregiver may need to move the chair or table closer so the person can comfortably reach their meal.

   
   

3. Difficulty getting into a car

   Getting into a car requires several visual-spatial judgments at once: where the seat begins, how far down it is, where the doorframe is, and how the body needs to move into the space. Someone with decreased depth perception may have difficulty determining where the seat actually is. They may start lowering themselves before they are positioned over it or appear unsure of how far they need to move.

   
   

4. Not knowing how high a step is

   Stairs and curbs can become especially challenging. A person may be able to see the step but have difficulty determining its height or depth. They may lift their foot far higher than necessary, hesitate before stepping, or misjudge where their foot should land. These difficulties can contribute to falls, which is one reason changes in depth perception deserve attention.

5. Seeing a change in flooring as a step

   Imagine a carpeted living room connecting directly to a tiled kitchen. The surfaces may be completely level. They might stop at the edge, step unusually high over it, or treat the transition as though they were stepping up or down.

6. Trying to pick up flowers from a tablecloth

   Depth perception also helps the brain distinguish a three-dimensional object from something printed on a flat surface. If this processing is affected, the flowers printed on a tablecloth may appear to have shape, height, or dimension. A person may reach down and try to pick one up.

If you notice these changes in your loved one, talk with their healthcare provider.

They can help determine whether changes in eyesight or another condition may be contributing to what the person is experiencing.

Don’t wait for symptoms to become more noticeable or severe. An eye exam can help identify vision problems early and make sure treatable issues are not making everyday tasks even more difficult.

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This article was made by  Elder Love USA.

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