Question:

What is the difference between forgetfulness, dementia and Alzheimer’s disease?

Answered by Daniel Murman, MD, Nebraska Medicine neurologist:

It’s very common for older patients to complain of forgetfulness or what we medically call subjective cognitive complaint. Mild forgetfulness is often a normal part of aging.

However, once a person progresses beyond occasional forgetfulness, they may be experiencing symptoms of mild cognitive impairment or dementia. Mild cognitive impairment, or MCI, often precedes dementia, which is measured in three progressive stages: mild (early-stage), moderate (middle-stage) and severe dementia (late-stage). 

Mild Cognitive Impairment (MCI)

During this phase, patients have consistent but mild problems with memory or other aspects of thinking, such as coming up with names, remembering dates or appointments, or solving complex problems. However, patients with MCI are still independent in everyday activities, such as driving, handling their finances, medications, shopping and cooking. Symptoms in this stage include: 

• Consistent but mild forgetfulness.
• Less ability to remember names or appointments.
• Mild problems solving complex problems.

Early-stage dementia

During the mild or early stage of dementia, problems with memory and thinking worsen and now interfere with a patient’s ability to do more complex activities. Symptoms include:  

• Trouble driving, doing finances and cooking.
• Repeating questions, forgetting recent events, frequently misplacing things.
• Getting lost when driving in familiar locations.
• Trouble doing math, solving problems and fixing things.
• Needing reminders for medications or other tasks.

Middle-stage dementia

During moderate or middle-stage dementia, there are more severe declines in memory, decreased awareness of limitations, a clear problem with decision making and often trouble with communication. At this stage, patients need help performing basic daily tasks such as dressing and bathing. Symptoms may include:

• Very poor short-term memory, with new information rapidly lost.
• Increased confusion or poor judgment.
• Need around-the-clock supervision and assistance.
• Personality and behavioral changes, such as agitation or saying inappropriate things.

Late-stage dementia

During late-stage dementia or severe dementia, people may need full-time help at home with all activities. Severe symptoms may include:

• Inability to communicate.
• Require full-time assistance with things like eating, dressing and bathing.
• Loss of physical abilities such as walking, sitting or swallowing.

We can test a patient for MCI or dementia in our office to determine how well their brain is working using a short screening test, followed by more extensive neuropsychological testing. Neuropsychological testing accesses many areas of thinking, including memory, language, visual-spatial skills, attention, decision-making abilities and speed of processing. These test scores can then be adjusted for age, education and gender to determine which areas experience significant decline.

In many cases, patients check out just fine for their age. However, it is important to take these concerns seriously because if they should be tested and show signs of MCI or early-stage dementia, there may be disease-modifying medications available. In addition, documentation of more severe stages of dementia can help providers and families make important decisions, such as whether the patient should still be driving, whether a power of attorney should help the patient with decisions and whether additional assistance is needed in the care of the patient.

MCI and dementia are just staging categories and do not specify what is causing MCI or dementia.  Additional tests are needed to determine if it is Alzheimer's disease or if it is another cause of dementia.  If a person does show signs of dementia, this does not always mean they have Alzheimer’s disease. About 60% of dementia is caused by Alzheimer’s disease, 20% of cases are caused by vascular disease called vascular dementia, 10% to 15% by Lewy body disease, and the remaining cases are due to other causes.

There are now biomarkers available to determine if there is evidence of Alzheimer's changes in the brain. New drugs are available that can help slow the progression of Alzheimer’s disease by 30% or more in its early stages. 

Remember that experiencing frequent forgetfulness in your 50s or early 60s may not be normal and should be evaluated by your health care provider. Forgetfulness at this age can be a sign of other health issues or medication imbalances that need to be addressed. As patients get older and experience consistent forgetfulness that begins to impact their everyday activities, an evaluation is required to rule out early symptoms of degenerative dementia, such as Alzheimer's disease or related dementia.