Dementia doesn’t change what people think about, but it does change the way people think. Most people who have dementia continue to be interested in the same things they were interested in before their diagnosis. The way they express their interests may be different, and they may not be able to remember as much. But they likely think about the same things they did before they were diagnosed. Understanding how people who have dementia think can help you be a more effective caregiver and take better care of yourself.
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Dementia affects every aspect of the thought process.[01,02,03] While it’s easy to take the process of thinking for granted, it’s more complicated than it may seem. There are several steps involved, and each step depends on our ability to do something else. For example, to pay our electric bill, we need to:
It’s well-known that dementia makes it difficult to remember things, including the sequence of actions required to complete a task. But dementia also affects a person’s motivation. In the later stages of the disease, people who have dementia often develop what’s called apathy. They become uninterested or unconcerned about things they used to care about.
So, a person who has dementia may still think about their household bills. But the way they think about them, and what they’re able to do with those thoughts, is different because dementia has caused their “nerve cells, or neurons, to stop working properly, and eventually die.”[04]
For people who have dementia, most or all steps in the thought process are delayed or blocked in some way. In the early stages of dementia, many people can still complete activities of daily living (ADLs) without help. They can still dress themselves, feed themselves, and clean themselves. The instrumental activities of daily living (IADLs), such as managing money, medications, or a social calendar are more difficult than basic tasks in the early stages of the disease.
In later stages, even basic actions and processes become difficult. People begin to struggle with ADLs because their brains have forgotten what seem like simple things to do.
While scientists are still working to fully understand how dementia affects the brain, the cognitive and behavioral symptoms of dementia are well-recorded.
People who have dementia experience increasing moments of confusion or inability to remember things. Your loved one may become disoriented while shopping and accidentally take unpurchased merchandise from a store because they forgot to check out. Or they may ask you to give them the car keys because they’ve forgotten that they no longer own a car or drive. People who have dementia also forget:
As their brains change, people who have dementia continue to try to make sense of their own actions and surroundings, but the damage done to their brains makes this more difficult.[05] For example, if your loved one previously worked in a doctor’s office, and is now going to their own doctor’s appointment, their mind may tell them that they’re at work rather than visiting their own doctor.
Read more:Dementia and Paranoia: Triggers and Tips
Accepting a diagnosis of dementia can be especially difficult. Your loved one may express denial as they are processing this new information.
Being unable to easily perform normal tasks may cause your loved one to exhibit what may seem to you like outsized frustration. As they forget basic processes that you may take for granted, their experience of having dementia can build on itself.
“As dementia begins and progresses, the person will notice their increasing memory difficulties and will be aware that they’re struggling to cognitively function as they used to,” explains Erin Martinez, Ph.D., Associate Professor of Gerontology at Kansas State University.
In situations where your loved one struggles to do something they used to know how to do, fear and frustration — coupled with a new difficulty in verbally expressing confusion — can result in aggression. “It’s entirely normal and common to experience a range of complex emotions in response to these challenges, including frustration, anger, sadness, and denial,” Dr. Martinez says.
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Dementia causes changes in the brain that affect how people experience the world through their senses. These sensory changes can be very disorienting and may cause even more confusion, delusions, or aggression. For example, a person with dementia may experience vision changes, mobility issues, and loss of hearing, smell, and taste.
Lewy body dementia causes a build-up of Lewy bodies in the parts of the brain that process visual information.[06] People with this condition may perceive things differently or not see them at all. People who have dementia caused by other conditions, such as Alzheimer’s, may be able to perceive visually as they used to, but their brains may not be able to process the information. For example, they may see a person’s face, but may not recognize that the face is their daughter’s.
Hearing loss and dementia are more common as we age. If someone simply can’t hear, hearing aids can help. But if someone’s brain can’t make sense of what they’re hearing, their thought process will be negatively affected.[01] Dementia makes it harder for a person to understand purpose and relationships.[02] It also makes it more difficult to concentrate. In conversations, a person with dementia can easily become confused because their brains aren’t able to stay focused or grasp the meaning of the discussion.[07,08]
Also, not being able to hear can be very isolating. Your loved one may avoid social situations altogether because they’re embarrassed to tell others they can’t hear.
Dr. Martinez explains, “Many people hesitate to acknowledge their hearing loss, and a common but harmful response is to withdraw from social interactions. This social withdrawal carries serious consequences, because social isolation and loneliness are linked to numerous health problems.”
“What starts out as untreated hearing difficulties can escalate into higher risks for heart disease, stroke, depression, anxiety, and even earlier mortality,” she says.
Losing the ability to smell — also known as olfactory dysfunction — is common among people who have dementia. The ability to taste is closely connected to the ability to smell, so people who can’t smell also often can’t taste either.[09]
People who have dementia also lose interest in things that used to motivate them.[03] Even if they can still smell or taste food, they may lose interest in eating altogether.
Dr. Martinez notes, “Sensory changes significantly affect our nutritional habits. With diminished taste and smell perception, people often overcompensate by adding too much salt and sugar. This behavior raises the risk of high blood pressure, complicates diabetes management, and negatively impacts overall health.”
Dementia often affects a person’s ability to perform multiple actions in a specific sequence.[02] An activity as simple as getting up from a chair and walking to the mailbox can be difficult for a person who has dementia. They must first think of going to the mailbox, remember where the mailbox is, get up from the chair, and walk to the mailbox. Dementia makes it difficult for them to stay focused so they can accomplish each step in that process.[02]
It’s common for older adults who have cognitive impairments to experience a decline in mobility and an increase in disability.[10] They may trip over objects or a pet, slow their walking speed to compensate for unsteadiness, or find it difficult to hold and use utensils when eating. Dementia symptoms can look similar, so if you see these occurrences in your loved one’s daily life, you may want to take them to a doctor.
Most people who have early-to-middle-stage dementia are aware of their own memory deficits. They may forget what seem like minor things, such as a favorite recipe. As the disease progresses into later stages, your loved one may not remember that they have the condition.
Some people who have Alzheimer’s disease may experience anosognosia, which means they truly don’t understand that they have a disease or deficit.[11] If your loved one is experiencing anosognosia, talk with their doctor about specific things you can do to help.[12]
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As a caregiver, you’re better equipped to understand your loved one’s experience when you can empathize with how they’re experiencing the world. Understanding this can help you:
“The most effective and satisfied caregivers recognize that maintaining their own health is not optional – it’s essential,” Dr. Martinez says.
“When caregivers neglect their own well-being, they risk compromising the quality of care they strive to provide to their loved one,” she explains.
Paranoia is a common symptom of dementia. Brain damage, hallucinations, memory problems, fear and anxiety, or changes in the environment or in a person’s routine can all cause someone to feel like other people are a threat.
A delusion is a strongly held belief that doesn’t change even when evidence proves it’s untrue. In people who have dementia, delusions can be caused by brain damage, changes in a person’s routine and environment, or changes in caregivers.
If your loved one believes that a deceased person is still alive, try to understand that their mind truly can’t tell the difference between the past and the present. Rather than trying to force them to acknowledge reality, validate their feelings and gently redirect their focus to the present.
Gently and respectfully acknowledge their reality. Offer to investigate their concerns and report what you found. But don’t push them to accept reality – that can cause them to become more agitated. Accepting your loved one’s confusion is one way you can cope with dementia.
Rather than argue with your loved one about where they are, reassure them that they’re safe. They may be feeling unhappy or lonely and may be interpreting those feelings as being away from home, where they felt happy and engaged. Help them connect with a positive long-term memory of home.
Yokoi T. (2012). Why do dementia patients become unable to lead a daily life with decreasing cognitive function? Dementia.
Cipriani G, Danti S, Picchi L, et al. (2021, June). Daily functioning and dementia. Dementia Neuropsychology.
Dening KH. (2019, June 21). Evidence-based practice in dementia for nurses and nursing students. Jessica Kingsley Publishers.
National Institute on Aging. (2025, April 1). What is dementia?
Örulv L, Hydén LC. (2006, October). Confabulation: sense-making, self-making and world-making in dementia. Discourse Studies.
Assil, K. (2023, August 22). Eyesight problems linked to dementia: what that means for you. Assil Gaur Eye Institute of Los Angeles.
Ray M, Dening T, Crosbie B. (2019, August 5). Dementia and hearing loss: A narrative review. Maturitas.
Johns Hopkins Bloomberg School of Public Health. Hearing loss and the dementia connection.
Laukka EJ, Ekstrom I, Larsson M, et al. Markers of olfactory dysfunction and progression to dementia: A 12-year population-based study. (2023, January 23). Alzheimer’s & Dementia.
Jayakody O, Breslin M, Ayers E, et al. (2022, June) Relative trajectories of gait and cognitive decline in aging. The Journals of Gerontology Series A.
Cleveland Clinic. (2022, April 21). Anosognosia.
Alzheimer’s Foundation. (2021) Why can’t my loved one see that they need help? Alzheimer’s Today.
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