When your loved one was first diagnosed with dementia, the doctor probably spent some time explaining what kind of dementia they think it is, where it may have come from, and maybe even which parts of the brain are affected.
And if you’re like most caregivers, very little of that stuck. It’s hard to process all of that information while someone in your family is getting a dementia diagnosis. That’s totally normal.
So let’s go over the basics: what the lobes of the brain are, what each one does, and how dementia affects each of them.
Dementia Is a Category, Not a Diagnosis
Careblazer, dementia isn’t actually a specific diagnosis. It’s a category. It’s the word we use to describe a group of symptoms someone has when they’re having trouble with their thinking, to the point that it affects their daily functioning.
Trouble with memory, attention, processing speed and executive functioning are all possible symptoms of dementia.
If you’re still wondering how dementia is different from Alzheimer’s disease, I explain it in is dementia the same as Alzheimer’s disease?
There are a lot of different reasons someone might have problems with their thinking. But whatever is causing it, it comes back to how well the brain is working. So to understand what’s happening in the brain of someone with dementia, we first have to learn a little about how the brain works.
The brain is so complex, and symptoms vary depending on the type of dementia. That’s why we see people with the same diagnosis have different symptoms.
What Are the Lobes of the Brain?
The brain is divided into two hemispheres, the right and the left. Each hemisphere has four lobes:
- The frontal lobe
- The parietal lobe
- The temporal lobe
- The occipital lobe
Try saying that three times fast.
Each lobe has its own job. And all of them talk to one another.
Frontal Lobe: Planning, Judgment and Controlling Behavior
You guessed it. The frontal lobe is in the front part of the brain, right behind your forehead. It’s the largest lobe of the brain.
The frontal lobes are involved in planning, organizing, decision making and thinking ahead. They’re also involved in memory, attention, controlling behavior, managing emotions and language. So you can see why they’re so important.
No matter what type of dementia your loved one has, as it gets worse it starts to affect all areas of the brain. So even if their dementia didn’t start in the frontal lobes, that doesn’t mean it won’t start affecting them.
When dementia starts to affect the frontal lobes, this is where you may see:
- Impulsive behaviors
- Really poor judgment or decision making
- Socially inappropriate behavior, like no longer having a filter and saying things most people wouldn’t say out loud
- Hypersexual behaviors
- A hard time planning an activity
- Trouble starting a task, because the frontal lobes are also involved in initiation. They may not know how to begin.
- Difficulty controlling emotions and behaviors
A lot of the time, when we talk about difficult dementia behaviors, we’re really talking about behaviors affected by the frontal lobe.
Some types of dementia start in the frontal lobes, like frontotemporal dementia. That’s where these behavioral and emotional symptoms show up among the very first signs. Often one of the first signs of frontotemporal dementia is a significant change in personality or behavior.
But someone with another type of dementia, say Alzheimer’s disease, can start to show these symptoms too, as the disease reaches their frontal lobes.
Parietal Lobe: Touch, Navigation and Getting Dressed
The parietal lobe sits behind the frontal lobe. Its job is to process sensory information. This is where the brain makes sense of everything coming in.
The parietal lobes contain the primary sensory cortex, which controls our sense of touch. This is also the area of the brain that tells us when something is too hot, too cold or painful. It helps us walk around and navigate the world without constantly bumping into things, and know which way is up and which way is down.
When dementia affects the parietal lobe, your loved one might:
- Seem clumsy, or keep bumping into things
- Have a hard time putting on their clothes
- Mix up right and left
- Have trouble reading and writing
- Have a hard time identifying parts of their body, or in some cases not recognize parts of their own body
Temporal Lobe: Memory and Language
The temporal lobes sit behind the frontal lobes and below the parietal lobes.
This is the part of the brain primarily responsible for memory. That’s because the temporal lobes hold something called the hippocampus, which is responsible for learning new information and holding on to it.
So when dementia affects the temporal lobes, your loved one may have significant memory problems.
Why They Remember the Past but Forget Yesterday
Maybe you’ve noticed that your loved one’s memories from a long, long time ago seem to be okay, especially the ones attached to an emotion. But newer memories they forget really quickly.
Part of the reason is where those memories are stored. Long-term memories that have been around for a while, especially ones with emotional meaning, are stored throughout the brain. Newer memories that haven’t been around that long, and don’t have that emotional tie, stay mostly within the temporal lobe.
So when something is wrong with the temporal lobes, those newer memories are the ones that get damaged. Memories stored in other areas of the brain are better preserved.
The temporal lobe is also involved in creating new memories: who you talked to yesterday, what you did yesterday, what’s happening right now. So it makes sense that when the temporal lobe isn’t working properly, your loved one has a hard time remembering things that happened recently.
Trouble Finding and Understanding Words
The temporal lobe is also important for speech and language, both producing sounds and understanding them. So besides memory problems, your loved one might have:
- Trouble finding the right word
- Trouble saying words
- Trouble understanding words, so you’re telling them something and it seems like it isn’t registering at all
Occipital Lobe: Vision
The last lobe of the brain is the occipital lobe. For some reason, it’s the hardest one for me to pronounce.
It’s in the back of the brain, and ironically, it’s responsible for vision. Yet it’s the lobe furthest away from your eyeballs.
In dementia, changes here can affect someone’s ability to understand shapes, process colors, and even tell the difference between the sizes of things.
I go further into how dementia changes what your loved one sees, and how to keep them safe, in how dementia changes vision.
Why Understanding the Brain Helps With Dementia Behaviors
The brain is very complicated. This isn’t an in-depth look at all things brain. It’s an introduction to the different lobes of the brain, what they’re mainly responsible for, and how that can affect someone who has dementia.
In a lot of my videos, you’ve heard me say that the person with dementia is not intentionally trying to do things that don’t make sense, or to give you a hard time.
A lot of the time, their brain isn’t functioning properly. Something is happening in the lobes that’s causing that behavior, that challenge, that difficulty.
My hope is that understanding a bit more about the brain helps you understand how this disease can lead to the really confusing behaviors you sometimes see in your loved one.
For more on how the brain works and what changes in dementia, read fascinating brain facts: how does it work in dementia?
When those confusing behaviors keep coming, it helps to have someone explain what’s behind them. Inside the Care Collective, we talk through exactly that every week: what’s happening in the brain, how to respond in real life, and how to take care of yourself while you’re caring for your loved one. You can learn more here.
