How Alzheimer’s disease changes the brain

June 21, 2023 Providence Neuroscience Institute


In this article: 

  • As part of Alzheimer’s & Brain Awareness Month, find out how this condition and other types of dementia change the brain. 

  • New research is looking for ways to diagnose Alzheimer’s disease early. 

  • Experts at Providence Neuroscience Institute are passionate about protecting your brain’s health as you age. 

Your healthy brain is full of billions and billions of neurons — special brain cells that communicate using chemical and electrical signals. Your neurons help you do everything from think and remember, to walk and talk. Each neuron can be connected to up to 7,000 other neurons in a huge web of communication. 

But Alzheimer’s disease and other forms of dementia disrupt this web and interrupt signals between neurons, leading to devastating effects. 

How Alzheimer’s disease and related dementia change the brain 

Alzheimer’s disease destroys neurons and their connections (synapses) to one another in a few different ways: 

  • Microglia cells in the brain that are supposed to clear away waste such as plaque and proteins stop working. 
  • Amyloid plaques, a type of protein, build up between neurons and block communication. 
  • Tau proteins, called tangles, build up between neurons involved with memory. 
  • Microglia cells begin to release chemicals that cause inflammation that damages neurons. 
  • Blood vessels in the brain become blocked or hardened, reducing how much blood, oxygen and glucose get to brain cells. 
  • Without proper oxygen and glucose, neurons die or stop working properly. 
  • All of these problems together cause brain tissue to shrink (atrophy).   

While these are microscopic changes in the brain, they cause huge changes to how a person functions. These changes typically start in specific areas of the brain. Changes begin in the temporal lobe which controls memory, but then progress to the frontal lobe (which controls behavior and judgment) and the parietal lobe (which controls language). 

Symptoms of Alzheimer’s only get worse as the disease progresses and neurons continue to die.  

Many people with Alzheimer’s disease follow a similar path of symptoms, including: 

  • Memory loss 
  • Poor judgment and decision-making skills 
  • Losing track of time or place 
  • Trouble handling money or paying bills 
  • Losing things 
  • Changes in mood or personality 
  • Depression, anxiety or aggression 
  • Trouble reading or writing 
  • Trouble sleeping 
  • Difficulty getting dressed or completing other daily tasks 
  • Hallucinations 
  • Emotional outbursts 
  • Inappropriate and impulsive behavior, such as getting undressed in public 

Eventually, Alzheimer’s affects basic functions such as speaking, walking, sleeping and swallowing. At this point, the brain is much smaller and has lost a huge number of neurons. 

New research helps detect brain changes and Alzheimer’s disease early 

More than 6 million older adults in the U.S. have Alzheimer’s disease and millions more have other dementias such as vascular dementia, dementia with lewy bodies, frontotemporal dementia or Parkinson’s disease. Ongoing research is looking for ways to help these people through treatment, prevention and early detection. 

New blood tests are looking at ways to detect Alzheimer’s years before symptoms begin. These tests look for high levels of tau proteins in the blood. Current clinical trials of these tests show that they are highly accurate in diagnosing Alzheimer’s disease. 

At Providence, we are also researching a new, faster cognitive screening to identify Alzheimer’s and dementia. This 3-minute tool helps primary care physicians screen more adults for dementia, even when their symptoms are only mild. Providence experts are also using widely available tools such as MRI and EEG together to more accurately diagnose dementia by looking for changes in brain structure. 

Early diagnosis matters when it comes to dementia and Alzheimer’s disease.  

While there is no cure for Alzheimer’s disease right now, it can be slowed down with lifestyle changes such as

  • Quitting smoking 
  • Increased exercise 
  • Controlling blood pressure 
  • Staying socially active 
  • Drinking less alcohol 

There are also a few medicines that can help slow down memory loss. Others can remove amyloid plaques from the brain, improving cognitive function. However, these medicines only work for a limited time in the early stages of the disease. People who are diagnosed early may also have the opportunity to try new medicines through clinical trials.   

Providence Neuroscience Institute can help with dementia 

Neurologists at Providence help care for Alzheimer’s disease and all types of dementia. We use the latest tools to diagnose the disease as early as possible and provide medical treatments.

We encourage you to take steps today to protect your brain in the future. Talk to your primary care physician about help with diet, exercise and quitting smoking. 


Find a doctor 

If you are looking for a neurologist, you can search for one who’s right for you in our provider directory. 

Download the Providence App 

We’re with you, wherever you are. Make Providence’s app your personalized connection to your health. Schedule appointments, conduct virtual visits, message your doctor, view your health records and more. Learn more and download the app

Related resources 

Hear Me Now podcast: Dementia and memory care 

Dementia isn’t certainty: how to modify your risk  

Piloting an innovative tool to detect cognitive decline 

This information is not intended as a substitute for professional medical care. Always follow your health care professional's instructions. 

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