Dementia is not a specific disease but is rather a general term for the impaired ability to remember, think, or make decisions that interfere with doing everyday activities. Though dementia mostly affects older adults, it is not a part of normal aging.
Common Types of Dementia — per Centers for Disease Control and Prevention (CDC)
Alzheimer’s Disease: This is the most common cause of dementia, accounting for 60 to 80 percent of cases. It is caused by specific changes in the brain. The trademark symptom is trouble remembering recent events, such as a conversation that occurred minutes or hours ago, while difficulty remembering more distant memories occurs later in the disease. Other concerns like difficulty with walking or talking or personality changes also come later. Family history is the most important risk factor. Having a first-degree relative with Alzheimer’s disease increases the risk of developing it by 10 to 30 percent.
Vascular Dementia: About 10 percent of dementia cases are linked to strokes or other issues with blood flow to the brain. Diabetes, high blood pressure and high cholesterol are also risk factors. Symptoms vary depending on the area and size of the brain impacted. The disease progresses in a step-wise fashion, meaning symptoms will suddenly get worse as the individual gets more strokes or mini-strokes.
Lewy Body Dementia: In addition to more typical symptoms like memory loss, people with this form of dementia may have movement or balance problems like stiffness or trembling. Many people also experience changes in alertness including daytime sleepiness, confusion or staring spells. They may also have trouble sleeping at night or may experience visual hallucinations (seeing people, objects or shapes that are not actually there).
Frontotemporal Dementia: This type of dementia most often leads to changes in personality and behavior because of the part of the brain it affects. People with this condition may embarrass themselves or behave inappropriately. For instance, a previously cautious person may make offensive comments and neglect responsibilities at home or work. There may also be problems with language skills like speaking or understanding.
Mixed Dementia: Sometimes more than one type of dementia is present in the brain at the same time, especially in people aged 80 and older. For example, a person may have Alzheimer’s disease and vascular dementia. It is not always obvious that a person has mixed dementia since the symptoms of one type of dementia may be most prominent or may overlap with symptoms of another type. Disease progression may be faster than with one kind of dementia.