I was asked that question recently. It is a good question so I have written down the key concepts.
Let’s start with defining dementia. The National Institute on Aging defines it as “an umbrella term used to describe a range of neurological conditions affecting the brain that get worse over time.”
Alzheimer’s Disease is just one example of the diseases that can lead to dementia. It is also the most common cause of dementia.
Alzheimer’s disease results from the buildup of a protein that interferes with numerous brain functions. Forgetfulness and confusion are common symptoms. As a result the person may wander, be forgetful, get lost easily, and repeat the same questions over and over again.
There are 3 other common causes of dementia that will be briefly described here. The first is Frontotemporal dementia. It results from an abnormal protein entering nerve cells in the front part of the brain (frontal lobes) and the sides of the brain (temporal lobes). This form of dementia is more likely to affect younger people than Alzheimer’s.
Damage to the frontal lobes causes impairments in planning, controlling impulses, and other “executive” functions in the brain.
Damage to the temporal lobes impairs the ability to speak and to understand speech. Such patients also tend to have disturbed emotions, be apathetic, lack sympathy, and have compulsive behavior.
The next type of dementia is Lewy Body dementia. It also results from an abnormal protein. Common symptoms include poor concentration and attention, disorganization, illogical ideas, insomnia, poor coordination, reduced movement of the facial muscles, and having detailed visual hallucinations.
Interestingly, their cognitive abilities and alertness can vary significantly throughout the day and from one day to another.
The third cause of dementia I’ll describe is Vascular Dementia. In this case blockage of blood vessels to and within the brain cause damage that affects memory, makes it difficult to learn, causes poor judgment, and they may have hallucinations or delusions.
There are many other causes of dementia such as Traumatic Brain Injury, the effects of using drugs, Huntington’s Disease, and others. Determining what type of dementia a patient has requires a careful history and physical exam and various lab and imaging tests. For example, there is a type of PET scan that can identify Alzheimer’s disease.
There are also a number of medical conditions that mimic dementia that doctors must identify because they are often treatable.
Some examples include low levels of vitamin B12, insufficient thyroid hormone, excessive alcohol use, normal pressure hydrocephalus, and others.
Alas, there is no cure for dementia, but the progression of the disease can be slowed down in some cases. See my recent blog on a new medication for Alzheimer’s disease.
There are things we can do to reduce the likelihood of getting dementia. I plan to describe these in an upcoming blog.
Peter M. Hartmann, MD
Family Medicine & Psychiatry
