Dementia-related hallucinations happen because of changes in the brain that affect how it processes information. When someone has dementia, parts of their brain that handle memory, perception, and thinking start to break down or work differently. This can cause the brain to misinterpret signals or even create images and sounds that aren’t really there.
One key factor is damage or loss in areas like the visual cortex—the part of the brain responsible for seeing—and other regions involved in processing sensory input. When these areas receive less information from the eyes due to damage or disease, they may become overactive on their own. This overactivity can lead to vivid visual hallucinations where people see things that don’t exist around them.
In some types of dementia such as Lewy Body Dementia, abnormal protein clumps called Lewy bodies build up inside nerve cells. These proteins disrupt normal cell function and communication between neurons. The result is not only memory problems but also early and frequent visual hallucinations along with movement difficulties similar to Parkinson’s disease.
Another example is Charles Bonnet syndrome, which occurs when vision loss causes the brain’s visual centers to generate images without real input from the eyes—leading to complex hallucinations like seeing patterns, people, or animals.
Chemical imbalances also play a role. For instance, lower levels of acetylcholine—a neurotransmitter important for attention and perception—can upset how different parts of the brain communicate with each other. This imbalance may tip sensory processing toward false perceptions rather than accurate ones.
Hallucinations tend to be more common during times when a person feels tired or confused; this includes periods known as sundowning where symptoms worsen as daylight fades. Fatigue and increased confusion can make it harder for affected brains to filter out incorrect sensory signals.
Overall, dementia-related hallucinations arise because damaged brains struggle with interpreting reality correctly due to structural changes (like neuron loss), chemical shifts (neurotransmitter imbalances), and disrupted communication pathways within critical regions responsible for sensing and understanding our surroundings. These factors combine so that what a person experiences visually or auditorily does not always match what is actually present in their environment.
