Everyone has mild memory lapses from time to time. You go from the kitchen to the bedroom to get something, only to find yourself wondering what you needed. You can't find your car keys one day and your reading glasses the next.
Lapses such as these are usually just signs of a normal brain that's constantly prioritizing, sorting, storing, and retrieving all types of information. So how do you know when memory loss is abnormal and warrants evaluation by a health professional? Here are some questions to consider:
- Does the memory loss disrupt daily living? "If memory loss prevents someone from doing activities that they had no trouble handling before—like balancing a checkbook, keeping up with personal hygiene, or driving around—that should be checked," says John Hart, Jr., M.D., professor of behavioral and brain sciences at the University of Texas at Dallas and medical science director at the Center for BrainHealth.
- How often do memory lapses occur? It's one thing to occasionally forget where you parked your car, but it's not normal to forget where you parked every day or to forget appointments over and over. Frequent memory lapses are likely to be noticeable because they tend to interfere with daily living.
- What kinds of things are being forgotten? "It's normal to forget the name of someone you just met, but may not be normal to permanently forget the name of a close friend or relative," Hart says. "It also may not be normal to never remember meeting a person after you have spent a great deal of time with them." Most people have trouble remembering some details of a conversation, but forgetting whole conversations could signal a problem. Other red flags: frequently repeating yourself or asking the same questions in the same conversation.
- Are there signs of confusion? Serious memory lapses may cause individuals to get lost in a familiar place or put something in an inappropriate place because they can't remember where it goes. Putting the car keys in the refrigerator is an example.
- Is the memory loss getting worse? Memory loss that gets progressively worse over time should be evaluated by a health professional.
What Can Cause Memory Loss?
Anything that affects cognition—the process of thinking, learning, and remembering—can affect memory. Doctors use a combination of strategies to gain better insight into what's going on, says Ranjit Mani, M.D., a neurologist and medical reviewer in the Food and Drug Administration's (FDA's) Division of Neurology Products.
Doctors evaluate memory loss by taking a medical history, asking questions to test mental ability, conducting a physical and neurological examination, and performing blood and urine tests. Brain imaging, using computerized axial tomography (CAT) scans or magnetic resonance imaging (MRI), can help to identify strokes and tumors, which can sometimes cause memory loss. "The goal is to rule out factors that are potentially reversible and determine if the memory loss is due to a more serious brain disease," Mani says.
Causes of memory loss, some of which can occur together, include the following:
- Medications. Examples of medications that can interfere with memory include over-the-counter and prescription sleeping pills, over-the-counter antihistamines, anti-anxiety medications, antidepressants, some medications used to treat schizophrenia, and pain medicines used after surgery.
- Alcohol and illicit drug use. Heavy alcohol use can cause deficiencies in vitamin B1 (thiamine), which can harm memory. Both alcohol and illicit drugs can change chemicals in the brain that affect memory.
- Stress. Stress, particularly due to emotional trauma, can cause memory loss. In rare, extreme cases, a condition called psychogenic amnesia can result. "This can cause someone to wander around lost, unable to remember their name or date of birth or other basic information," Mani says. "It usually resolves on its own."
- Depression. Depression, which is common with aging, causes a lack of attention and focus that can affect memory. "Usually treating the depression will improve mood and the memory problems may then also improve," Mani says.
- Head injury. A blow to the head can cause a loss of consciousness and memory loss. "Memory loss from head trauma typically stays the same or gradually gets better, but not worse," Mani says.
- Infections. People with HIV, tuberculosis, syphilis, herpes, and other infections of the lining or substance of the brain may experience memory problems.
- Thyroid dysfunction. An underactive or overactive thyroid can interfere with remembering recent events.
- Sleep deprivation. Lack of quality sleep—whether from stress, insomnia, or sleep apnea—can affect memory.
- Nutritional deficiencies. Deficiencies of vitamins B1 and B12 can affect memory. Such deficiencies can be treated with a pill or an injection.
- Normal aging. As part of the normal aging process, it can be harder for some people to recall some types of information, such as the names of individuals.
- Mild cognitive impairment. Mild cognitive impairment (MCI) is a condition characterized by a memory deficit beyond that expected for age, which is not sufficient to impair day-to-day activities.
- Dementia. Dementia is a term used for a condition in which there is increasing impairment of memory and other aspects of thinking that are sufficiently severe to impair day-to-day activities. There are many causes of dementia, but the most common by far is Alzheimer's disease (AD), in which there is a progressive loss of brain cells accompanied by other abnormalities of the brain. A diagnosis of AD is made by confirming that a patient has dementia and by excluding other conditions, such as brain tumors, vitamin deficiencies, and hypothyroidism.
Can Memory Loss Be Prevented?
There is no conclusive evidence that the herb ginkgo biloba prevents memory loss. And research has shown that the combination of estrogen and progestin increased the risk of dementia in women older than age 65.
So what can you do to prevent memory loss? Clinical trials are under way to test specific interventions. While those tests are being conducted, you may want to consider hints from animal and observational studies of promising approaches. These steps are already beneficial in other ways and may help reduce the risk of developing memory problems.
- Lower cholesterol and high blood pressure. A number of studies in recent years have suggested that vascular diseases—heart disease and stroke—may contribute to the development of AD, the severity of AD, or the development of multi-infarct dementia (also called vascular dementia).
- Don't smoke or abuse alcohol. According to a research report from Harvard Medical School, "Improving Memory: Understanding Age-Related Memory Loss," smokers perform worse than nonsmokers in studies of memory and thinking skills. Heavy alcohol use can also impair memory.
- Get regular exercise. Physical activity may help maintain blood flow to the brain and reduce risk factors associated with dementia.
- Maintain healthy eating habits. According to a study published in the Oct. 24, 2006, issue of Neurology, eating vegetables may help slow down the rate of cognitive change in adults. Researchers studied 3,718 residents in Chicago who were older than age 65. Of the types of vegetables, green leafy vegetables had the strongest association with slowing the rate of cognitive decline. Also reducing foods high in saturated fat and cholesterol and eating fish with beneficial omega-3 fatty acids, such as salmon and tuna, may benefit brain health. An NIA-funded clinical trial to test the effects of omega-3 fatty acids in people with AD is now recruiting patients nationwide.
- Maintain social interactions. Social interaction can help reduce stress levels and has been associated with a lower risk of dementia. In the February 2007 issue of the Archives of General Psychiatry, researchers found that loneliness is associated with an increased risk of late-life dementia.
- Keep your brain active. Some experts suggest that challenging the brain with such activities as reading, writing, learning a new skill, playing games, and gardening stimulates brain cells and the connections between the cells, and may be associated with a lower risk of dementia.