Alzheimer’s Disease

What is Alzheimer’s disease?

Alzheimer’s disease is a type of dementia. Dementia refers to a group of disorders that leads to a decline in brain functions — including memory, decision-making, and the ability to perform daily tasks. It can also affect mood, personality, and behavior. Alzheimer’s is the most common form of dementia. It accounts for around 70% of all dementia cases. 

Alzheimer’s disease was named after Dr. Alois Alzheimer, a German psychiatrist. He reported on a patient — Auguste D — who exhibited what we now know to be the symptoms of Alzheimer’s. When she died, he examined her brain tissue and noted some key findings. These included plaques on the neurons and tangles in the nerve fibers.

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Causes of Alzheimer’s disease

Researchers are still trying to understand the cause of Alzheimer’s. Under the microscope, they know that the disease results from amyloid plaques and neurofibrillary tangles in brain tissue. These changes affect communication between brain neurons. 

It’s not clear what causes these changes in the brain to happen. But studies have uncovered some risk factors for Alzheimer’s:

• Age: Alzheimer's usually affects people in their 60s and older. Early-onset Alzheimer's is much less common, making up about 10% of all cases. 

• Genetics: Several different genes increase risk for Alzheimer’s. Mutations of the genes APP, PSEN1, and PSEN2 are linked with early-onset dementia. The gene APOE-e4 increases risk for late-onset Alzheimer’s. 

• Race: Alzheimer's is more likely to affect African American and Hispanic people. 

• Sex: Alzheimer's is also more likely to affect people with female anatomy than people with male anatomy.

• Lifestyle: Lack of sleep, tobacco and alcohol use, lower educational level, diet, and exercise patterns all seem to affect dementia risk.

• Health conditions: Vascular disease, obesity, high cholesterol, diabetes, hypertension, and traumatic brain injury all increase risk of Alzheimer’s.

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Symptoms of Alzheimer’s disease

Alzheimer’s disease usually starts with subtle symptoms. These signs can be difficult to detect in the beginning stages. But symptoms become more noticeable with time:

• Memory loss: In early stages, this can look like normal forgetfulness. But if someone has Alzheimer’s, they’re more likely to forget an event or conversation that just happened.

• Difficulty with daily tasks: It can be harder to do things like pay the bills or use appliances. Eventually, this difficulty affects basic self-care like bathing and dressing. 

• Difficulty planning and organizing: People may experience more trouble with making a shopping list, keeping appointments, or taking medications. 

• Trouble with directions: A common sign of dementia is getting lost easily or making errors when following familiar routes. 

• Language problems: People with Alzheimer's often struggle to find the right word or substitute words. 

• Impaired judgment: Alzheimer's often affects executive function. This refers to higher brain functions, including decision-making, planning, and insight. 

• Misplacing items: Someone may misplace items in odd spots, such as putting keys in the refrigerator. 

• Mood changes: People with Alzheimer's are at increased risk for emotional symptoms. They may seem more depressed or withdrawn from people or activities. 

• Social withdrawal: People with Alzheimer's often self-isolate. Social settings and gatherings may feel stressful, overwhelming, or disorientating.

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How is Alzheimer’s disease diagnosed?

There’s no single test that can diagnose Alzheimer’s. Instead, it’s a clinical diagnosis. This means a healthcare professional makes the diagnosis based on:

• Symptoms: A healthcare professional will take a thorough inventory of the signs and symptoms you and those around you have noticed. 

• Family history: This will help figure out if you have genetic risk for Alzheimer’s. 

• Physical examination: A thorough physical exam — particularly of the nervous system — will help find other potential causes of the symptoms. 

• Cognitive testing: These tests assess memory and brain function. They can show certain patterns that may point to Alzheimer’s. 

• Laboratory testing: Blood tests can rule out other causes of memory loss. But, at the moment, there’s not a blood test to diagnose Alzheimer’s. 

• Brain imaging: An MRI or CT scan can’t diagnose Alzheimer’s, but they can rule out other conditions. There’s also a newer test — an amyloid positron emission tomography (PET) scan — that can see amyloid plaque on the brain. But this test is expensive, and Medicare and other insurance plans don’t always cover it. 

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Medications for Alzheimer’s disease

There are currently three classes of Alzheimer’s prescription medications available:

1. Cholinesterase inhibitors: These medications work by slowing the breakdown of acetylcholine, a chemical in the brain that helps neurons communicate. Examples include donepezil (Aricept, Adlarity), rivastigmine (Exelon), and galantamine (Razadyne ER).

2. NMDA receptor antagonists: The NMDA receptor in the brain can become overstimulated in Alzheimer's and result in faster brain cell damage. This medication decreases that nerve stimulation. Memantine (Namenda, Namenda XR) is the only one in this class. There’s also a combination available that contains both memantine and donepezil (Namzaric). 

3. Monoclonal antibodies: These are the first medications to potentially change the course of Alzheimer's by reducing amyloid plaques in brain tissue. Options include donanemab (Kisunla), lecanemab (Leqembi), and aducanumab (Aduhelm). Note that Aduhelm will no longer be available after November 1, 2024.

Studies of more medications and a potential vaccine are ongoing. There are also medications to treat Alzheimer's symptoms outside of memory loss, like agitation and insomnia. 

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Living with Alzheimer’s disease

Alzheimer’s disease can be a hard diagnosis to process — and even harder to live with — for individuals and their loved ones. People and families have many difficult considerations, including:

• Prognosis: Many people are curious about life expectancy after an Alzheimer’s diagnosis, but this can vary greatly. Estimates range from 3 to 10 years. But it can be much longer. Healthy lifestyle, especially regular exercise, may slow cognitive decline in Alzheimer’s.

• Caregiver well-being: If you’re caring for someone with Alzheimer’s, it’s important to connect with resources for education and support. This is a challenging job, and caregiver burnout can have serious implications on your own health and wellness.

• Advance directives: End-of-life planning makes sure people with Alzheimer's receive care that’s in line with their wishes. It’s best to do this before memory loss is advanced, but that’s not always possible. This includes advance care planning, documents like a living will, medical and durable power of attorney, and sometimes a do-not-resuscitate (DNR) order.

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Can Alzheimer’s disease be prevented?

There’s no medication or treatment that will prevent Alzheimer’s. But there are some habits that may lower dementia risk. The World Health Organization (WHO) recommends the following to lower your risk for Alzheimer’s:

• Exercise regularly.

• Avoid tobacco use.

• Avoid daily alcohol intake or binge drinking.

• Maintain a weight that’s comfortable for your body.

• Eat foods that help keep your brain healthy, like the Mediterranean diet.

• Maintain a healthy blood pressure.

• Maintain healthy cholesterol levels.

• Maintain healthy blood sugar levels.

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