Seeing is a complex process that involves multiple stages. The eyes transmit visual information to the brain, where it is processed alongside input from other senses, thoughts, and memories. This intricate process culminates in what we recognise as visual perception. However, when this system is disrupted, particularly in individuals with dementia, it can lead to visuoperceptual difficulties—issues that involve both vision and perception. In dementia, the brain’s ability to accurately interpret visual information is often compromised, leading to a range of visual and perceptual errors that can significantly impact daily life. Given the complexity of the visual system and the cognitive changes associated with dementia, a variety of errors can arise, further complicating the challenges faced by those living with this condition.
Ageing and Visual Challenges
As we age, various visual challenges become more prevalent, including reduced visual acuity, difficulties with depth perception, and smaller pupils. Additionally, common eye conditions such as cataracts, glaucoma, macular degeneration, and diabetic retinopathy can exacerbate these issues. For individuals with dementia, these visual challenges can be even more pronounced, often leading to a distorted perception of reality.
Distortion of Reality
Individuals with dementia may experience visual distortions due to various factors, including insufficient contrast, excessive shininess, or misinterpretation of colours and shapes. For example, a person with dementia may become frightened by a patterned carpet or a busy wallpaper design, perceiving them as something threatening or unfamiliar.
Misinterpretation
Misinterpretation occurs when the brain makes a “best guess” based on distorted or incomplete visual information received from the eyes. This is often due to damage to the visual system itself, rather than the interpretative processes. For instance, shadows may be mistaken for holes in the ground, causing confusion and anxiety.
Misidentification
Damage to the brain areas responsible for recognising objects and familiar faces can lead to misidentification. This could also be compounded by expressive aphasia, where the person struggles to express what they see accurately. As a result, a person with dementia might confuse a husband for a son or fail to recognise everyday objects, such as a tap or a chair, which can be disorienting.
Motion Blindness
Some individuals with Alzheimer’s disease may experience motion blindness, a condition where they perceive the world as a series of still frames rather than continuous motion. This can cause them to become disoriented or lost, even in familiar environments, as they struggle to make sense of their surroundings.
Everyday Challenges
People with dementia may have difficulty interacting with their environment due to these visual perception issues. For example, they might struggle to reach for a cup of tea, mistaking its position, or they might perceive images on television as real people. Shiny flooring can appear wet or slippery, leading them to avoid walking on it. Additionally, some may no longer recognise their own reflection in a mirror, further contributing to their confusion and distress.
Suggested Guidelines
- Safety First: Lock away hazardous materials and liquids. Use childproof locks on cupboards containing dangerous items, and hide the locks to prevent access.
- Simplify the Environment: Remove rugs, wallpaper, or objects that could be misinterpreted as stairs, holes, or other dangers. Avoid patterns that could confuse or frighten.
- Control Lighting: Diffuse sharp light by removing mirrors and glass tabletops that can create disorienting reflections or glare.
- Personal Interaction: Always introduce yourself to a person with dementia, especially if they have visuoperceptual problems. Approach them from within their visual field to avoid startling them.
- Familiarity and Comfort: When in a new environment, guide your loved one with physical touch or allow them to follow closely for reassurance. Ensure that everyday objects are kept in consistent, specific places to help them navigate their surroundings.
- Guidance: Install strips of lights to guide the person to important areas, such as the bathroom, particularly during the night.
By understanding and accommodating the visuoperceptual challenges associated with dementia, we can create a safer and more supportive environment for our loved ones, helping to alleviate some of the confusion and fear they may experience.