What Is Alzheimer’s Disease?

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What Is Alzheimer’s Disease?

Pam Belluck, April 30, 2016

More than five million Americans are believed to have Alzheimer’s, two-thirds of them are women. Geri Taylor 72, is one of them. Credit Michael Kirby Smith for The New York Times. Alzheimer’s disease can seem frightening, mysterious and daunting. There are still a lot of unknowns about the disease, which afflicts more than five million Americans. Here are answers to some common questions:

Sometimes I forget what day it is or where I put my glasses. Is this normal aging, or am I developing Alzheimer’s?

Just because you forgot an item on your grocery list doesn’t mean you are developing dementia. Most people have occasional memory lapses, which increase with age. The memory problems that characterize warning signs of Alzheimer’s are usually more frequent, and they begin to interfere with safe or competent daily functioning: forgetting to turn off the stove, leaving home without being properly dressed or forgetting important appointments. Beyond that, the disease usually involves a decline in other cognitive abilities: planning a schedule, following multistep directions, carrying out familiar logistical tasks like balancing a checkbook or cooking a meal. It can also involve mood changes, agitation, social withdrawal and feelings of confusion, and can even affect or slow a person’s gait.

How is Alzheimer’s diagnosed?

Diagnosing Alzheimer’s usually involves a series of assessments, including memory and cognitive tests. Clinicians will also do a thorough medical work-up to determine whether the thinking and memory problems can be explained by other diagnoses, such as another type of dementia, a physical illness or side effects from a medication. Brain scans and spinal taps may also be conducted to check for corroborating evidence like the accumulation of amyloid, the hallmark protein of Alzheimer’s, in the brain or spinal fluid.

What causes Alzheimer’s?

The cause is unknown for most cases. Fewer than 5 percent of cases are linked to specific, rare gene mutations. Those are usually early-onset cases that develop in middle age. In the vast majority of cases, Alzheimer’s disease makes its presence known after age 65, and the older one gets, the greater the risk. Aside from age, which is the single biggest risk factor, there are health issues that can increase the chances of developing Alzheimer’s. Heart and vascular problems, including stroke, diabetes and high blood pressure, appear to increase the risk of Alzheimer’s and other dementias. Depression has also been associated with increased risk.

People with one copy of the ApoE4 gene variant have two to four times as much risk of developing Alzheimer’s as people without the variant, and people with two copies of ApoE4 have about 10 times the risk. That risk appears to be larger in women. Carriers of ApoE4 also have a greater chance of developing symptoms at a younger age. About 25 percent of people have one copy of ApoE4; about 3 percent have two copies.

Is there any way to prevent Alzheimer’s?

Many researchers have been trying to figure this out. So far there is no clear answer. There are hints that behaviors that keep us healthy and engaged—exercise, healthy diet, social activities, educational activities—may keep dementia at bay for some time, probably because those behaviors promote overall brain and body health, as well as emotional well-being. Education may promote what is called cognitive reserve, essentially the idea that the more we learn and stimulate our brains, the more brain cells we have that can temporarily compensate for some memory and thinking problems. But no vitamin, supplement or brain game has been found to be a magic wand.

What are the stages that precede Alzheimer’s?

Before developing symptoms of Alzheimer’s, some people, but not all, experience a condition called mild cognitive impairment. One type of MCI affects memory. Another type affects perception or decision-making skills. Both types involve a slight decline in these abilities, but it does not prevent the person from functioning independently. People with MCI have a greater risk of developing Alzheimer’s, but it is not inevitable.

Recently, scientists have begun to recognize an even earlier state that can precede dementia, called subjective cognitive decline. This occurs when people notice lapses in their memory or thinking that worry them, even if those around them are not really aware of the lapses. Dementia experts have found that sometimes people recognize these issues before they reach the threshold of a clinical diagnosis, and that those people may be more likely to eventually develop Alzheimer’s. Alzheimer’s itself typically involves mild, moderate and severe stages. Mild and especially moderate stages can last years, and there is often no way to predict a person’s pace and path of decline.

Are there any medications for Alzheimer’s?

There are five drugs approved to treat Alzheimer’s, sold under the names Aricept, Exelon, Namenda, Namzaric and Razadyne. These drugs either slow the breakdown of the neurotransmitter acetylcholine or block the overproduction of glutamate in the brain, but none have been shown to work very well for very long.

The search for more effective medications has been met with years of failure. One theory behind that failure is that many drugs have been tested on patients too far along in the disease; their brains may have been too damaged for the drugs to have an effect on their symptoms. Many of the drugs developed so far target the amyloid protein that forms plaques in the brains of Alzheimer’s patients, because many scientists believe that amyloid buildup is a cause of Alzheimer’s.

Recent research has found that amyloid begins accumulating 20 years or more before symptoms of dementia occur, and advancements in scans that can detect amyloid are making it possible to identify people in earlier stages, including some who have no symptoms of dementia yet. Several clinical trials are underway, including large trials testing anti-amyloid drugs at these early stages. It will be several years before solid results are known.