How Alzheimer’s Affects the Brain: A Primer for Caregivers

Everyone who cares for someone with Alzheimer’s disease (AD) knows too well that the disease is a thief who over time steals the most precious parts of those they love –their memories, ability for personal sharing and self expression, thinking and planning skills, and eventually their sense of themselves.

Caring for someone throughout the stages of AD can leave caregivers feeling powerless, unprepared, and frustrated; but understanding how Alzheimer’s affects the brain of its victim can help ease these feelings and the worry that comes naturally as the disease continues to change the behaviors and abilities of the person affected.

“Understanding how Alzheimer’s affects the brain can help caregivers know more about what to expect as their loved one progresses through the disease, and how to prepare for that progression,” says Peter Reed, Ph.D., Senior Director of Programs for the Alzheimer's Association. “Reducing the amount of surprise makes caregiving less stressful and helps caregivers to better care for themselves and their loved one.” AD often has a predicable progression; understanding the disease at every level can help caregivers assess changes to ensure appropriate medical follow-up, to implement continuing safety measures, and to plan for the future needs of their loved one.

Diagnosis by Default

“Alzheimer's disease is not natural aging. It is a progressive disease that causes the abnormal death of brain cells,” says William H. Thies, Ph.D., Vice President, Medical and Scientific Relations at the Alzheimer's Association. “The initial symptoms of Alzheimer’s often include memory loss, but as the disease progresses it kills more of the brain until the person is unable to move, swallow or breathe.” 

According to the Alzheimer’s Association as many as 5 million Americans have the disease and every 72 seconds someone develops it – over 10% of people over the age of 65 have AD and the percentages go up as age increases. The direct and indirect costs of AD and other dementia illnesses are over $148 billion dollars annually now, and that figure continues to rise as the population ages and people live longer. 

Alzheimer’s disease diagnosis is typically a default choice and there are a host of other possibilities that can cause similar symptoms, many of which can be successfully treated. Vitamin deficiencies, endocrine disorders, fluid and electrolyte imbalances, low blood sugar, infections, brain abnormalities, circulation problems, lung ailments that prevent the proper utilization of oxygen, medications, metabolism problems, and kidney failure can all cause similar symptoms and behavior changes in the elderly.

Each possibility needs to be ruled out before a definitive diagnosis of Alzheimer’s can be made and treatment begun– and when it comes to AD, time is not on the side of the person afflicted. Researchers are racing against time to understand the changes in the brains of potential AD victims as early as possible, and to develop new medicines, in the hopes of stopping or even preventing the disease.

Understanding the Normal Brain Structures

The first step to understanding the Alzheimer’s brain is to understand a little about the normal healthy brain. The human brain is nothing short of amazing; from its larger structures, down to its tiniest cells, it is arguably the most important and the least understood organ in the human body.

The larger, easily visible structures of the brain contain the cerebrum, the cerebellum and the brain stem. Scientists have been able to map the general regions, and lobes, that drive a person’s skills and reactions, allowing them to better understand the progress of Alzheimer’s. 

The cerebrum is the largest part of the organ and takes up most of the space in the skull. It holds the regions of the brain responsible for body movement, memory, problem solving, thinking skills, and feeling; no doubt you have already guessed that this is where the first Alzheimer’s afflicted brain cells begin to make their demise known.

Next, at the back of the skull just under the cerebrum, sits the cerebellum. This part of the brain is responsible for the body’s balance and coordination.

Last is the brain stem; this smallest structure of the three main regions of the brain sits beneath the cerebrum and in front of the cerebellum, and connects the spinal cord to the brain. It controls the major physical functions necessary for life: breathing, heart rate, blood pressure and digestion.

Let’s look at how all those structures communicate – in short how the work of the brain is accomplished. The adult brain contains over 1 billion neurons, or nerve cells, that interconnect at more than 1 trillion points, or synapses, like the branches of a tree. The small filament ends of the neurons also have microtubules, small structures that bring nourishment to the nerve cells. Scientists call this network of connections the neuron forest.

Electrical signals travel through this dense forest of nerve fibers to interpret, alert, feel and remind the body. The body produces small amounts of dozens of chemicals called neurotransmitters at the juncture of the neurons that are released as a result of the electrical signal. These neurotransmitters carry the signals to the other nearby nerve cells. These are the neurons that Alzheimer’s destroys: the tiny structures that individually and collectively accomplish the work of the brain.

Alzheimer’s and the Brain

By the time a person starts to show the very first symptoms of Alzheimer’s disease, the brain’s structures are already deteriorating. The plaques and tangles that characterize the illness are already spreading in a mostly predictable pattern disrupting the electrical signals and the neurotransmitters; and as the nerve cells die the brain itself begins to shrink.

Two key areas in the brain: the cortex, the outer layers covering the brain and responsible for higher level thinking, planning and memory, and the hippocampus, the brain center where new memories are formed, shrink dramatically. The normally small fluid filled ventricles, or spaces, in the brain enlarge.

So far scientists don’t yet fully understand what causes brain tissue loss and cell death in a person with Alzheimer’s disease, but two processes are always seen. The AD brain has both plaques made up of fragments of beta-amyloid protein, and tangles made up of dead and dying neurons whose fine microtubules become twisted and collapse when tau, a normal brain protein, becomes abnormal.

While the disease worsens over time in a mostly predictable fashion, the speed of progression is variable. Those diagnosed with Alzheimer’s live an average of eight years, but some have lived for as long as 20 years.

Brain Changes: a Predictable Pattern

In the earliest stages of the disease, plaques and tangles begin to form in the brain in the learning, memory, thinking and planning centers well before symptoms are noticeable--sometimes 20 years or more before diagnosis. Often people have mild to moderate Alzheimer’s symptoms before diagnosis and treatment is sought. By this time a person’s memory and thinking skills are impacted enough to interfere with work, social relationships, decision making, and in some cases personal safety.

Over time, as the plaques and tangles spread throughout the brain, individuals may begin to show changes in their personality as well as in their behaviors. Confusion can lead to angry outbursts and even violence, wandering and paranoia. There can be a loss of the sense of the space and in relation to where their body is compared to the objects around them making walking and even reaching for objects difficult. Both understanding speech and speaking can become impossible tasks. As the brain deteriorates dramatically so does the quality of life for the Alzheimer’s sufferer.

There is currently no cure or even accurate tests to predict who will get AD, but there is help and reason to be hopeful as researchers work diligently to identify changes in the brain structures of potential sufferers in the disease’s earliest stages and to develop medicines to slow and even halt its progression. It is realistic to believe that soon great strides will be made as scientists are better able to understand how AD affects the brain.

“The Alzheimer’s Association believes that we will defeat Alzheimer’s disease,” says doctor Thies. “Researchers are working diligently to find new treatments, preventions and early detection for Alzheimer’s disease and it is essential that we increase funding for more research. There are several drug treatments in Phase III clinical trials that show promise to slow or stop the progression of Alzheimer’s. 

It is essential that people with the disease and their families take part in this process by volunteering for clinical trials. Improved treatments can never become a reality without testing in volunteers.”  Knowledge is the most powerful item in the tool kit of a caregiver of a victim of Alzheimer’s disease.

Angela Butera Dickson is a Registered Nurse and freelance medical writer living in Rhode Island. She has been published over 800 times and has 25 years of practical nursing experience in hospice, acute & long term care, psyche nursing, and home care.

Related Links

The Alzheimer's Association
The website includes an online slide presentation, “Inside the Brain: an Interactive Tour.”