In my clinical work, I often test people to determine whether they might be experiencing memory changes that are due to a dementia condition. The thing is, most people seem to have little idea about what dementia actually means. Even among doctors, many assume that Alzheimer’s disease and dementia are the same thing. They are not. In this post, I’d like to clarify the difference between dementia and Alzheimer’s disease.
Let’s start with dementia.
Dementia is a term that simply refers to a category of functioning. Much like the term “learning disability”, it refers to a broad category, but not any specific disorder. When someone has dementia, they have impairment in their cognitive abilities such as memory, speed of thinking, or language, that is severe enough to cause them impairment in their daily functioning. For example, if someone’s memory is so poor that they can’t appropriately take their medication or remember to eat meals, that might qualify them for a diagnosis of dementia.
Now, there are many different things that can cause someone to have dementia. Basically any brain disorder that causes impairment significant enough to affect daily functioning could lead to a diagnosis of dementia. Some people with Parkinson’s disease go on to develop cognitive impairment that qualifies for dementia. Significant brain injuries or strokes can also lead to dementia if the damage is bad enough.
The Difference Between Dementia and Alzheimer’s Disease
The most common type of dementia is that caused by Alzheimer’s disease, making up 50-70% of dementia cases. Alzheimer’s is a degenerative condition in the brain. It breaks down neurons, which are the cells that communicate signals back and forth in your brain. The primary symptoms caused by Alzheimer’s disease are short term memory loss, trouble with verbal communication, and disorientation. In the early stages of the disease, someone will not have dementia. They might ask repetitive questions or have some trouble finding the right word to say in conversation that seem fairly normal for an elderly person. However, as time goes on, the disorder progresses and breaks down more neurons, causing further difficulties. At a certain point, when someone’s memory loss becomes severe enough, they are going to start to struggle with their daily activities such as paying their bills or appropriately bathing. This is when they would qualify for dementia. In this case, it would be dementia due to Alzheimer’s disease.
Essentially, this is all on a spectrum. When someone first develops Alzheimer’s disease, they will not have dementia. They will function relatively normally. As the disease progresses, they will start to have minor changes in their thinking abilities that would qualify them for a middle stage referred to as “mild cognitive impairment”. Once the disease causes changes that significantly disrupt the person’s daily living skills, as described above, then they would be considered to have dementia due to Alzheimer’s disease.