Dementia is the name for a group of brain disorders that make it hard to remember, think clearly, make decisions, or even control your emotions. Alzheimer’s disease is one of those disorders, but there are many different types and causes of dementia.
Dementia isn’t just about simple memory mishaps -- like forgetting someone’s name or where you parked. A person with dementia has a hard time with at least two of the following:
- Communication and speech
- Focus and concentration
- Reasoning and judgment
- Visual perception (can’t see the difference in colors or detect movement, or sees things that aren’t there)
Since some types of dementia share similar symptoms, it can be hard for a doctor to figure out which one you or your loved one has. Be sure to tell him about all symptoms, medication and alcohol use, and previous illnesses to help him make the right diagnosis.
Alzheimer’s Disease (AD)
This is the most common type of dementia. About 60% to 80% of people who have dementia have Alzheimer’s. It’s a progressive condition, which means it gets worse over time, and it usually affects people over 65 years old. There’s currently no cure.
It happens when proteins (called plaques) and fibers (called tangles) build up in your brain and block nerve signals and destroy nerve cells. Memory loss may be mild at first, but symptoms become worse over time.
It gets more difficult to carry on a conversation or perform everyday tasks. Confusion, aggression, and mood changes are other common symptoms.
A doctor can’t say you have Alzheimer’s with absolute certainty, but there are things he can do to be fairly sure. They include tests of your attention, memory, language, and vision, and looking at images of the brain. These images are taken with an MRI (magnetic resonance imaging), which uses powerful magnets and radio waves to make detailed pictures.
Other Types of Dementia
Vascular dementia: This is the second most common type. About 1 in 10 people who have dementia have vascular dementia, which happens when there’s not enough blood going to your brain. This can be caused by damage to your blood vessels or blockages that lead to mini-strokes or brain bleeding. Doctors used to call it multi-infarct or post-stroke dementia.
Unlike Alzheimer’s disease, memory loss isn’t the typical first symptom. Instead, people with vascular dementia can have different signs, depending on the area of the brain that’s affected, such as problems with planning or judgment. No drugs have been approved to treat this type of dementia, but you can do some things to keep your brain and blood vessels healthy and try to prevent future damage. These include exercising, eating well, and not smoking.
Dementia with Lewy bodies: Lewy bodies are abnormal clumps of a protein called alpha-synuclein. They build up in your cortex, the part of your brain that handles learning and memory.
This type of dementia causes problems with attention and things like driving early on, along with sleeping issues, seeing things that aren’t there (hallucinations), and slowed, unbalanced movements, similar to Parkinson’s disease symptoms. Memory loss tends to show up later in the disease.
Mixed dementia: Sometimes, a person has brain changes caused by more than one type of dementia. This is called mixed dementia. For example, you may have blocked or damaged blood vessels in your brain (vascular dementia) and brain plaques and tangles (Alzheimer’s disease) at the same time.
Frontotemporal Dementia (FTD): This form of dementia involves the loss of nerve cells in the front and side areas of your brain -- behind your forehead and ears. Personality and behavior changes and trouble with language are the main symptoms. Some people also have a hard time with writing and comprehension.
Symptoms usually show up around age 60 -- earlier than they usually start with Alzheimer’s disease. Types of frontotemporal dementia include behavioral variant FTD (bvFTD), primary progressive aphasia, Pick's disease, corticobasal degeneration, and progressive supranuclear palsy.
Creutzfeldt-Jakob Disease (CJD): This rare form of dementia happens when a protein, called a prion, folds into an abnormal shape, and other prions start to do the same. This damages brain cells and triggers a fast mental decline.
People with CJD also have mood changes, confusion, twitchy or jerky movements, and trouble walking. Sometimes, the disease is passed down through families, but it also can happen for no known reason. One type, called variant CJD (or mad cow disease, also known as bovine spongiform encephalopathy), has spread from cattle to people in certain situations.
Huntington's disease : This is caused by a problem with a gene you get from one of your parents. It affects the central part of your brain -- the area that helps you think, move, and show emotion.
Symptoms typically start between ages 30 and 50, and uncontrolled arm, leg, head, face, and upper body movements are the first signs. The brain changes also lead to problems with memory, concentration, judgment, reasoning, and planning. People with Huntington’s disease also have issues with depression, anger, and irritability. There’s no known cure for it.
Normal pressure hydrocephalus: The Alzheimer’s Association includes this buildup of spinal fluid in the brain as a form of dementia. Symptoms include slowed thinking, problems with decision making, trouble concentrating, behavior changes, difficulty walking, and loss of bladder control. It typically strikes adults in their 60s or 70s. Surgery to put a shunt in your brain to get rid of extra fluid can help.