Dementia is an umbrella term referring to cognitive decline. There isn’t just one type of dementia, and knowing which type a person has can help aid in treatment.
The most common form of dementia is Alzheimer’s disease, but it is definitely not the only one.
Below you will find a quick reference guide to the common types of dementia.
Types of dementia
Alzheimer’s disease: Alzheimer’s is the most common form of dementia, and close to 5.1 million Americans over the age of 65 are affected by this debilitating disease. To date, there is no definitive test to diagnose the condition in living patients. Although the progression of Alzheimer’s cannot be stopped or reversed, an accurate early diagnosis will help patients and their families plan for the future and seek symptomatic relief.
Vascular dementia: Vascular dementia is the second most common form of dementia after Alzheimer’s disease. Vascular dementia can be caused by a series of small strokes brought on by a number of factors:
- Blood flow to the brain has been interrupted due to stroke.
- Blood stops flowing to the brain for longer than a few seconds, the brain cannot receive oxygen, so brain cells start dying as a result.
- Silent strokes show no symptoms, so damage can be done without the patient realizing it.
- Large strokes can affect strength, sensation, and other parts of the nervous system, contributing to vascular dementia.
Other risk factors for vascular dementia include:
- Hardening of the arteries
- High blood pressure
Vascular dementia can be further categorized into multi-infarct dementia and Binswanger’s disease.
Dementia with Lewy bodies (DLB): Lewy body disease – or dementia with Lewy bodies – is the second most common form of dementia after Alzheimer’s disease.
Lewy bodies are deposits of protein in nerve cells, impairing neurological communication and causing cell death as a result. At this point, researchers don’t really understand why they appear in the brain or how they lead to dementia. They do know that Lewy bodies are the underlying cause of a number of progressive diseases that impact the brain and nervous system, particularly dementia and Parkinson’s disease.
When the Lewy bodies are in the outer layer of the brain, the patient tends to have more problems linked to mental abilities. As LBD progresses, many people experience hallucinations. They might see animals or objects that aren’t really there. They also can have hearing problems. They might hear sounds such as knocking or footsteps that are not real. Their own walking can be stooped and unbalanced (as commonly seen in Parkinson’s patients). Violent movements can be common at night.
Diagnosis of DLB can be a challenge, because the condition often presents itself like other illnesses with similar symptoms.
When any form of dementia is suspected, the Lewy Body Dementia Association recommends a comprehensive examination. The doctor will talk to the patient, as well as someone who knows them really well, to discuss medical history, symptoms, how their lifestyle has changed, and any medications the person is taking. The patient will undergo mental ability tests that will include visual components such as drawing. A neurological examination that looks at reflexes and balance is also part of a thorough exam.
There is currently no cure for Lewy body dementia, but treatments are available to improve the symptoms and slow down the reduction in cognitive function.
Mixed dementia: This type of dementia is caused by one or more medical conditions. The most common mixed dementia combination is Alzheimer’s disease and vascular dementia.
Parkinson’s disease: This form of dementia mainly affects the movement. It is a progressive neurological illness, meaning, it gets worse over time. Parkinson’s patients will experience tremors in their limbs, stiffness, and lack of movement, which will only aggravate with time.
Again, the damage in the nerve cells within the brain is the culprit. The neurons in the brain region called substantia nigra contain dopamine, a chemical that controls the movement. When these neurons get damaged, the levels of dopamine drop, resulting in significant motor changes characteristic of Parkinson’s disease.
Frontotemporal dementia: Frontotemporal dementia (FTD) is a group of disorders characterized by the progressive loss of nerve cells within the brain’s frontal lobes (found directly behind the forehead) or temporal lobes (behind the ears). The loss of nerve cells in these regions onsets the deterioration of behavior and personality, along with changes to speech and muscle or motor functions.
There are three major types of FTD, including behavior variant frontotemporal dementia (bvFTD), primary progressive aphasia (PPA), and disturbances of motor function. Behavior variant frontotemporal dementia mainly leads to changes in personality and behavior and generally occurs in individuals in their 50s and 60s. Nerve cell loss in bvFTD is mostly seen in the areas of the brain that control conduct, judgment, empathy, foresight, and other abilities.
Primary progressive aphasia largely affects language, speech, writing, and comprehension. PPA can be subdivided into two variants: semantic and nonfluent/agrammatic. In the semantic variant, a person’s ability to understand or formulate words is lost. In nonfluent/agrammatic variant, speaking is hesitant, labored, and ungrammatical.
Lastly, disturbances of motor function appear in three disorders which are part of the frontotemporal degeneration spectrum. These are amyotrophic lateral sclerosis (ALS), corticobasal syndrome, and progressive supranuclear palsy (PSP).
Creutzfeldt-Jakob disease: This type of dementia is associated with prions, which are infectious agents that attack the central nervous system and invade the brain, causing dementia. This type of dementia is also known as mad cow disease. Symptoms include memory loss, speech impairment, confusion, muscle stiffness, lack of coordination, and susceptibility to falls. This type of cognitive decline can progress rapidly, and there is no cure.
Normal pressure hydrocephalus: This type of dementia is characterized by an accumulation of cerebrospinal fluid in the brain’s cavities. This results in an increased pressure in the brain, impeding normal brain functioning.
Huntington’s disease: This is an inherited type of dementia affecting a person’s cognition, behavior, and movement.
Wernicke-Korsakoff Syndrome: This form is caused by a deficiency in vitamin B1, and is commonly seen in alcoholics, malnourished individuals, and some cancer patients.