Dementia is a general term that refers to severe memory loss and problems with thinking, behavior, and social skills that interfere with daily life. According to the National Institutes of Health, this neurological condition affects one in seven adults over age 71.
Alzheimer’s disease is a type of dementia and makes up 60 percent to 80 percent of dementia cases, per the Centers for Disease Control and Prevention. Most cases of Alzheimer’s occur when people reach their 70s and 80s.
Although Alzheimer’s disease accounts for many dementia cases, other types of dementia are distinct from Alzheimer’s disease, such as vascular dementia and Lewy body dementia. Alzheimer’s disease differs from other diseases involving dementia when it comes to its symptoms, effect on the brain, and treatments.
The most prevalent type of dementia is Alzheimer’s disease, which is the fifth-leading cause of death for adults 65 and over. The illness is marked by difficulty remembering recent events. People with Alzheimer’s can usually recall the past, but have trouble remembering what transpired recently. An individual with Alzheimer’s disease may be able to tell you about their childhood in detail, but not about the previous day’s events. As the condition progresses, people can have challenges walking and talking, and may experience personality changes.
Physicians believe that a buildup of proteins in the brain causes Alzheimer’s disease. Alzheimer’s disease degrades neurons and their connections in parts of the brain involved in memory, and lesions form in the brain, preventing those affected from storing new memories. As the disease progresses, the brain shrinks. To treat Alzheimer’s, doctors prescribe medicine targeting the lesions in the brain.
In some cases, people can inherit a genetic predisposition for the condition. According to the Centers for Disease Control and Prevention, a parent with Alzheimer’s increases a person’s risk by between 10 percent and 30 percent. However, the Alzheimer’s Society reports that the genetic link is more robust in early-onset Alzheimer’s, where adults show symptoms beginning in their 60s.
Lewy Body Dementia
After Alzheimer’s, Lewy body dementia (LBD) is the second most common type of dementia; people with LBD often also have Alzheimer’s. LBD impairs areas of the brain involved in problem-solving and reasoning and is related to Parkinson’s disease, a neurological disorder affecting movement.
Symptoms of LBD include:
- Disruption in rapid-eye-movement (REM) sleep, where most dreaming occurs
- Poor regulation of body functions due to problems with the autonomic nervous system
- Movement difficulties, such as rigid muscles and slow movement
- Visual hallucinations
- Cognitive issues, such as confusion, diminished attention, and memory loss
In the brain, an abnormal buildup of proteins, known as Lewy bodies, causes LBD. These proteins are related to Parkinson’s. People with LBD also have the same kind of brain lesions as those with Alzheimer’s.
When individuals receive an LBD diagnosis, physicians often prescribe medications for Alzheimer’s and Parkinson’s.
Like Alzheimer’s, advanced age is the most significant predictor of LBD. However, a stroke increases a person’s risk of developing the disease.
Although vascular dementia shares symptoms with Alzheimer’s disease, such as memory loss, there are significant distinctions. The characteristic symptom of vascular dementia is slow speaking and thinking, as well as trouble with problem-solving.
Vascular dementia can happen when a stroke blocks a blood vessel in the brain. In many cases, more strokes follow, and the symptoms become more severe with each additional stroke.
Conditions that harm blood vessels and impair circulation, preventing oxygen and nutrients from reaching the brain, can also cause vascular dementia, such as diabetes, high blood pressure, and high cholesterol. Treating vascular dementia typically encompasses treating the underlying conditions. For example, a person with hypertension might focus on taking steps to lower their blood pressure.
People who have vascular dementia tend to experience symptoms earlier than those with Alzheimer’s, as the onset of vascular dementia commonly happens between ages 60 and 75.
Other Types of Dementia
In addition to Alzheimer’s, LBD, and vascular dementia, many other types of dementia exist, including:
- Frontotemporal dementia — Impairs the front and sides of the brain. People with frontotemporal dementia tend to develop the disease younger than those with other forms of dementia. The average age of onset is between 45 and 65.
- Creutzfeldt-Jakob Disease — Occurs when proteins infect the brain and cause problems with cognition, memory, balance, speech, vision, and mobility. Creutzfeldt-Jakob Disease is fatal, with most people passing away within a year of diagnosis.
- Huntington’s disease — A genetic condition that causes dementia. People can inherit Huntington’s from parents with the disease.
Check out resources for caregivers of individuals with dementia. Or, for support and to learn more about Alzheimer’s disease and related disorders, reach out to your local Alzheimer’s Association chapter.