Part 8: When the Brain Changes
What Happens to “I” in Advanced Dementia?
Imagine knowing someone for many years and slowly noticing changes in the way they think, behave, and respond to the world. Their familiar personality may seem different. They may become suspicious, lose interest in activities they once enjoyed, or struggle with everyday decisions. For families, these changes can be deeply confusing. They may wonder whether the person they knew is still there.
In our previous articles, we explored memory, identity, communication, and consciousness. Now, we bring these ideas together to understand what happens when neurological conditions begin to affect the brain more widely. How does the experience of being “me” change when the brain itself changes?
When Personality Begins to Change
Personality is not stored in one small area of the brain. It develops through the interaction of many systems involved in emotion, motivation, memory, decision-making, social behaviour, and the regulation of impulses. When dementia affects these systems, a person's behaviour and personality may change in ways that seem unfamiliar.
Someone who was once patient may become easily frustrated. A person who enjoyed social gatherings may withdraw from others. Another person may become less concerned about things that once mattered deeply to them. These changes can be difficult for families to understand, especially when they appear to reflect a complete change in character.
However, such changes can be related to the disease affecting the brain. They are not necessarily deliberate choices, and they should not automatically be interpreted as evidence that the person no longer cares about others.
Why the Same Person May Seem Different
The brain helps us interpret situations, understand other people's intentions, manage emotions, and decide how to respond. When these abilities change, the same situation can be experienced differently.
For example, a person who has difficulty interpreting their surroundings may feel confused or threatened in a place that once felt familiar. They may react with anger or fear when someone tries to help them. From the outside, the reaction may seem unreasonable, but the person may be responding to a world that no longer makes sense to them.
Understanding this possibility can change how we respond. Instead of asking only, “Why are they behaving like this?”, we can also ask, “What might they be experiencing that I cannot see?”
When the Brain Struggles to Make Sense of the World
Dementia can affect more than memory. Depending on the type and stage of the condition, it may also affect attention, language, visual processing, judgment, and the ability to recognize people or interpret familiar surroundings.
These changes can make ordinary activities surprisingly difficult. A person may struggle to find their way around their own home, misunderstand an object they have used for years, or have difficulty following a conversation. What appears simple to someone else may require more mental effort than the person can comfortably manage.
As these difficulties increase, the person may become frustrated, anxious, or withdrawn. Their reactions can sometimes communicate distress even when they cannot explain what is wrong.
What I Have Learned Through Dementia Care
In my work with people living with dementia, I have learned that behaviour deserves curiosity rather than immediate judgment. When a person becomes restless, refuses assistance, or reacts unexpectedly, there may be several possible explanations. They may be uncomfortable, frightened, tired, confused, or struggling to communicate a need.
Of course, not every behaviour has an obvious explanation, and sudden changes should not automatically be attributed to dementia. Pain, infection, medication effects, dehydration, and other medical problems can also cause changes in thinking or behaviour and may require prompt assessment.
This has reinforced an important lesson for me: behaviour is information, even when we do not immediately understand its meaning. Taking time to observe, listen, and consider the person's circumstances can help us respond with greater understanding.
Is the Person Still Themselves?
This is perhaps the most difficult question for families. When someone's memories, personality, communication, and behaviour change significantly, it can feel as though the person is becoming a stranger.
Science cannot give us a simple measurement of how much of someone's identity remains. Identity is not a single object that can be weighed or located in one brain region. It involves many interacting processes, and dementia can affect those processes in different ways and at different rates.
What we can say is that changes in memory, personality, or communication do not automatically tell us everything about a person's inner experience. A person may continue to show preferences, emotional responses, familiar habits, or moments of connection even as other abilities decline. These responses vary between individuals, and we should avoid assuming that everyone with dementia experiences the same things.
The person we know may become harder to recognize through familiar words and behaviours, but that is not a reason to withdraw respect, affection, or opportunities for meaningful interaction.
Caring for the Person, Not Just the Condition
As dementia progresses, care often needs to change alongside the person's abilities. Long explanations may become difficult to follow. Familiar routines, simple choices, a calm environment, and adequate time to respond may become increasingly helpful. Activities can be adapted to the person's remaining abilities and preferences rather than expecting them to perform as they once did.
Most importantly, the person should remain involved in decisions and daily activities as much as possible. Support should protect their dignity and independence while responding to their changing needs. Dementia may alter how someone communicates or participates in life, but care should never reduce them to a diagnosis.
The Changing Brain and the Question of “I”
Our journey began with a simple question: Who am I? We then explored how the brain contributes to our sense of self, how memories shape our personal story, and how dementia can affect the way that story is remembered and shared.
Advanced dementia makes this question even more challenging because several parts of the system may change together. Memory, language, judgment, emotional regulation, and awareness can all be affected, although not necessarily in the same way or at the same time.
Perhaps the most honest conclusion is that we cannot fully understand another person's inner world simply by observing what they can no longer do. We can study the brain, recognize the effects of neurological disease, and learn from a person's responses, but we must also remain humble about what we cannot know.
When the brain changes, our understanding of the person must change too.
Next: Part 9
When the Brain Begins to Shut Down
What Happens to Consciousness Near the End of Life?
In the next article, we will explore the brain's role near the end of life, including how changes in circulation, oxygen supply, and brain activity can affect awareness and responsiveness. We will distinguish established physiological knowledge from questions that science has not yet fully answered, continuing our journey toward understanding the biological limits of the “I” we call ourselves.