What Is Dementia?
Dementia is a broad term that describes a loss of thinking ability, memory, and other mental abilities.
Many things can cause dementia. It happens when the parts of your brain used for learning, memory, decision making, and language are damaged or diseased.
You might also hear it called major neurocognitive disorder. Dementia isn’t a disease. Instead, it's a group of symptoms caused by other conditions.
About 5%-8% of adults over age 65 have some form of dementia. This percentage doubles every 5 years after 65. As many as half of people in their 80s have some dementia.
Dementia symptoms may improve with treatment. But many of the diseases that cause dementia aren't curable.
Dementia Causes and Risk Factors
The most common causes of dementia include:
- Degenerative neurological diseases. These include Alzheimer's disease, Parkinson's disease, Huntington's disease, and some types of multiple sclerosis. These diseases get worse over time.
- Vascular disorders. These conditions affect the blood circulation in your brain.
- Traumatic brain injuries caused by car accidents, falls, concussions, etc.
- Infections of the central nervous system. These include meningitis, HIV, and Creutzfeldt-Jakob disease.
- Long-time alcohol or drug use
- Certain types of hydrocephalus, a buildup of fluid in the brain
Certain physical and lifestyle factors can put you at higher risk of having dementia, including:
- Dementia in your family
- Illnesses including diabetes, Down syndrome, heart disease, and sleep apnea
- Smoking, heavy alcohol use, poor diet, and lack of exercise
Dementia Signs and Symptoms
People with dementia have problems with thinking and remembering that affect their ability to manage their daily life. These are some signs to watch for:
- Short-term memory problems, like forgetting where you put something or asking the same question over and over
- Communication problems like not being able to come up with a word
- Getting lost
- Trouble with complex but familiar tasks, like fixing a meal or paying bills
- Personality changes, like depression, agitation, paranoia, and mood swings
Types of Dementia
Dementia can be split into two groups based on which part of the brain is affected.
- Cortical dementias happen because of problems in the cerebral cortex, the outer layer of the brain. They play a critical role in memory and language. People with these types of dementia usually have severe memory loss and can't remember words or understand language. Alzheimer's and Creutzfeldt-Jakob disease are two forms of cortical dementia.
- Subcortical dementias happen because of problems in the parts of the brain beneath the cortex. People with subcortical dementias tend to show changes in their speed of thinking and ability to start activities. Usually, people with subcortical dementia don't have forgetfulness and language problems. Parkinson's disease, Huntington's disease, and HIV can cause these types of dementia.
Some types of dementia affect both parts of the brain.
To treat dementia, doctors will treat whatever is causing it. About 20% of the causes of dementia are reversible.
Causes of dementia that may be reversible include:
- Alcohol or drug abuse
- Subdural hematomas, blood clots beneath the outer covering of the brain
- Normal-pressure hydrocephalus, a buildup of fluid in the brain
- Metabolic disorders such as a vitamin B12 deficiency
- Low levels of thyroid hormones, called hypothyroidism
- Low blood sugar, called hypoglycemia
- HIV-associated neurocognitive disorders (HAND)
These forms of dementia are partially manageable, but they aren't reversible and get worse over time:
Stages of Dementia
Usually, dementia goes through these stages. But it may vary depending on the area of the brain that’s affected.
1. No impairment. Someone at this stage will show no symptoms, but tests may reveal a problem.
2. Very mild decline. You may notice slight changes in behavior, but your loved one will still be independent.
3. Mild decline. You'll notice more changes in their thinking and reasoning. They may have trouble making plans, and they may repeat themselves a lot. They may also have a hard time remembering recent events.
4. Moderate decline. They'll have more problems with making plans and remembering recent events. They may have a hard time with traveling and handling money.
5. Moderately severe decline. They may not remember their phone number or their grandchildren's names. They may be confused about the time of day or day of the week. At this point, they’ll need assistance with some basic day-to-day functions, such as picking out clothes to wear.
6. Severe decline. They'll begin to forget the name of their spouse. They’ll need help going to the restroom and eating. You may also see changes in their personality and emotions.
7. Very severe decline. They can no longer speak their thoughts. They can't walk and will spend most of their time in bed.