Occasionally, you may forget where you left your keys, or why you walked into a room. In many cases, this type of common forgetfulness is merely due to preoccupation, fatigue, stress, or normal aging.
But if it continues, it's important to know that other diseases or conditions may be responsible for more serious memory loss — and some can be treated.
"Memory is made up of many circuits in the brain, and dozens of causes can destroy these sensitive connections," says Susan Colligan, PhD, head of neuropsychology at John Muir Health.
"Memory loss can be due to a functional or emotional problem, or it may be a neuroanatomical issue," she says.
Some causes that can wreak havoc with memory include traumatic brain injury (even if mild), stroke, depression, thyroid problems, hormonal imbalances, vascular conditions, high blood pressure, or drug or alcohol use. Other causes include malnutrition and side effects from medications.
"Overall," she says, "if memory seems to be a problem, it's important to take it seriously and check with your physician. It could be secondary to something else that is reversible."
Dr. Colligan stresses, "Don't forget to tell your physician what prescription medications you take, plus over-the-counter substances. These could have major interaction effects, including memory problems."
Memory declines with normal aging. As you get older, you begin to lose brain cells and your body starts to make less of the chemicals that your brain needs to work properly.
There are many types of dementias, with Alzheimer's being the most common. Frequently, people who have the disease are not aware of it.
Typical memory problems as you grow older may include paying a bill late, losing things from time to time, or forgetting what day it is and remembering later.
However, if you become unable to manage a budget, misplace something and are unable to retrace your steps to find it, or completely lose track of the date or season — and these things interfere with your daily life — you may have a more serious problem.
When memory loss happens with a general loss of other intellectual abilities, such as judgment and abstract thinking, and these worsen over time, a brain disorder such as Alzheimer's may be the problem.
Family members or friends may notice a change in their loved one's functioning and behavior, and bring them in for an evaluation.
"Dementia is still primarily a clinical diagnosis, and there is no blood test or scan result that confirms the diagnosis," according to Dr. Stephens.
A doctor conducts basic memory tests, or more in-depth assessments, such as a neuro-psychological evaluation. Brain scans and blood tests may rule out other causes of memory loss.
Unfortunately, Alzheimer's is a fatal, long-term disease that gradually robs an individual of reason, independence, and physical ability.
According to researchers, dementias are increasing in incidence as the population ages. Currently, more than 5 million Americans have Alzheimer's.
In Alzheimer's specifically, research shows a loss of nerve cells in memory centers. Plaques, or deposits between nerve cells, and tangles, twisted bundles of protein fibers, eventually kill nerve cells in brains affected by Alzheimer's.
While scientists don’t know for certain, most believe plaques and tangles block communication between the cells.
There are currently a variety of drugs on the market that can help slow the progression of the disease process. These drugs include cholinesterase inhibitors, which prevent the breakdown of acetylcholine, and memantine, which controls glutamate.
Both types of drugs help regulate brain chemicals important to learning and memory, but may not work in all patients, and do not reverse the progressive brain damage characteristic of Alzheimer's.
"These medications are not a cure and not a home run, but they can set back the clock," says Dr. Stephens. "Still, in the past ten years, huge strides in understanding the biochemistry and pathophysiology of Alzheimer's have been made," he adds.
Many products on the market claim they can help sharpen mental abilities or work against memory loss.
Whether it’s ordinary vitamins, ginkgo biloba, omega-3 fatty acids, or coenzyme Q10: there is very little conclusive evidence that these substances can delay or alleviate the symptoms of dementia.
For example, research is contradictory when it comes to vitamin supplements. Some studies show that low levels of a B vitamin, folate, can triple the risk of dementia, yet other studies show vitamin B supplementation does not slow mental decline.
The same sort of inconclusive data exists for vitamin E.
Experts also warn that the government does not regulate, control, or inspect supplements on the market so their purity and effectiveness is unknown.
However, when it comes to lowering your risk of dementia, there are certain things you can do:
"We are gaining a much better understanding of genetic and molecular mechanisms that give rise to the disease process," says Dr. Stephens.
"Later, specific interventions may be possible: blocking enzymes that give rise to toxic proteins, identifying genetic causes (there are families with a genetic pattern for Alzheimer's), and even developing Alzheimer's or dementia vaccines."
"There is a lot of hope," confirms Dr. Colligan. "There are many more studies being done now than ever before, and new interventions may be available within the next few years."