One of the most common questions patients and their loved ones ask is: What are the different types of dementia?

Dementia causes problems with a person’s memory, thinking, and ability to reason properly. Dementia occurs when parts of the brain, which are in charge of how we learn and retain information, holding our memories and making decisions, as well as our ability to speak and understand language, are damaged or diseased. 

It is common for people to think Alzheimer’s disease is separate from dementia, or that dementia is a disease in and of itself. When in fact, Alzheimer’s is a disease that causes those affected to suffer from dementia. Dementia causes memory loss, among other symptoms, but dementia is not a disease in and of itself. Various diseases can cause dementia, but a person wouldn’t have “dementia” alone. They’d had a disease that causes dementia to occur as a side-effect.

In this article, we will discuss the various types of dementia, and how they can be treated.


What is Dementia?

Another name for dementia is neurocognitive disorder, and as mentioned before, it is not a disease itself. Instead, it is a grouping of systems that are caused by other conditions.

Alzheimer’s disease is the most common cause of dementia in the U.S. Approximately 60% to 80% of people with dementia have Alzheimer’s. That said, there are as many as 50 other causes of dementia. Unfortunately, most of the diseases that cause symptoms of dementia are incurable, but they the symptoms can improve with the right treatments.


What Causes Dementia?

As mentioned above, dementia is a term that is used to describe severe changes in the brain, usually resulting in memory loss, changes in personality and mood swings. Dementia can cause a person to no longer be able to perform daily activities. 

Dementia can affect three areas of the functioning brain:

  • Language
  • Decision making
  • Memory

With those areas of the brain in mind, most cases of dementia are caused by a non-curable disease. That said, there are a few circumstances where dementia can be reversed, due to its underlying cause. Below, we’ve listed the most common causes of dementia: 

Nurse supporting the charge at nursing home

  • Degenerative Neurological Diseases – Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and some of the types of sclerosis. All of these diseases get worse with time.
  • Vascular Disorders – These are the types of diseases that affect one’s blood circulation to the brain.
  • Traumatic brain injuries that can result from accidents, falls, concussions, etc.
  • Infections that harm one’s central nervous system. These can include meningitis, HIV, and Creutzfeldt-Jakob disease. 
  • Long-time use of drugs or alcohol, especially excessively
  • Certain types of hydrocephalus, which is a build-up of fluid in the brain


Types of Dementia

Dementia can be divided into two groups, based on which part of one’s brain is affected by it.

Cortical Dementia

Cortical dementias occur when a problem with the cerebral cortex, the outer layer of the brain, is affected by certain diseases. This type of dementia affects one’s ability to remember or hold memories, as well as properly communicate. Generally speaking, people with cortical dementia usually have a severe loss of memory and are unable to remember words or understand language that they once knew and could speak and understand fluently. Alzheimer’s disease and Creutzfeldt-Jakob disease are two forms of cortical dementia.

Subcortical Dementia

Subcortical dementias happen due to problems in parts of the brain beneath the cortex. People who suffer from the effects of subcortical dementia tend to show changes in their thinking, and ability to use common sense. It may also cause those who suffer from the effects of subcortical dementia to have a difficult time starting or completing activities. That said, those who suffer from subcortical dementia effects will not have a hard time remembering things, and won’t suffer from language problems like those who suffer from the effects of cortical dementias. Parkinson’s disease, HIV, and Huntington’s disease will suffer from the effects of subcortical dementia.

There are some types of dementia, and stages of dementia, which affect both parts of a person’s brain. 


Most Common Causes of Dementia

Alzheimer’s Disease

Group of elderly people recalling old times together

Alzheimer’s disease is the most common type of dementia, and it falls under the frontotemporal dementia category. The exact cause of Alzheimer’s dementia is unknown. Alzheimer’s patients have amyloid plaques (an accumulation of an abnormal protein) that’s identified in certain areas of their brain, but it is unclear how much these plaques play a role in the disease or result of the disease. Although the majority of Alzheimer’s disease cases occur in patients over 65 years of age, there are some rare cases where the symptoms of alzheimer’s can occur in a persons 40s or 50s. This early onset Alzheimer’s disease may progress more rapidly than in cases diagnosed at a later age.

Vascular Dementia

Vascular dementia is the second most common cause of dementia, and it occurs due to multiple strokes within the brain. Usually these strokes go unnoticed, and the patient may not have associated symptoms such as weakness, visual loss or numbness. Patients with high blood pressure or heart disease, who go untreated, may be at an increased risk of developing vascular dementia. 

Frontotemporal Dementia

This type of dementia is associated with a pronounced atrophy or shrinkage of one’s frontal and temporal lobes within the brain. Forgetfulness and problems finding words and language are often associated with this type of dementia. Patients may have significant personality changes, impulsive behaviors, and poor judgement. Stiffness of ones muscles is often associated with frontotemporal dementia patients.

Normal Pressure Hydrocephalus

Normal pressure hydrocephalus is an abnormal enlargement of the ventricles, or fluid filled spaces within the brain, which cause pressure on areas of the brain. This can lead to problems with memory, walking, and often increase incontinence (inability to control urine flow). This may be identified with imaging of the brain through MRI or CT scams, and further testing may be required in order to confirm the diagnosis. Once diagnosed, this condition can be treated with placement of a shunt, used to drain the extra fluid. 

Huntington’s Disease

Huntington’s disease causes characteristic abnormal movements, called chorea, in affected individuals. Generally, these movements are the hallmark of the diagnosis. That said, problems with memory can precede the development of chorea by many years in some cases. Some of the most common symptoms of Huntington’s disease include:

  • Having a difficult time focusing on tasks
  • Problems with impulse control
  • Inability to speak clearly 
  • Extremely difficult time learning new things

Wernicke-Korsakoff Syndrome

Wernicke’s disease, also known as Wernicke’s encephalopathy, is a brain disorder caused by a lack of vitamin B-1, resulting in bleeding of the lower sections of the brain. This type of brain disorder may cause physical symptoms, such as double vision and/or a loss of one’s muscle and balance coordination. When Wernicke’s disease goes untreated for a long period of time, physical symptoms usually decrease, but the signs of Korsakoff syndrome will start to appear.

medicine, healthcare and old people concept – sad senior woman sitting on bed at hospital ward

Korsakoff syndrome is a memory disorder that occurs in people who’ve had Wernicke’s disease for a long time. People who are diagnosed with Korsakoff syndrome are likely to have trouble with the following:

  • Clearly processing information and/or understanding it
  • Learning new skills 
  • Remembering things and grasping both past and present information

Both of these conditions are usually grouped together as one condition, which is known as Wernicke-Korsakoff syndrome. Technically, it is not a form of dementia. That said, the symptoms that are associated with these conditions are similar to dementia, so they are often categorized as so. Wernicke-Korsakoff syndrome can be caused by malnutrition or a chronic infection of some sort. The most common cause of this condition is vitamin deficiency and alcoholism.

Alcoholic Dementia

This type of dementia is caused when patients drink heavily, causing a development in deficiency of one of the B vitamins. When this occurs, brain cells are unable to function normally and memory loss may take place. Often referred to as Korsakoff syndrome. Although this is commonly seen in alcoholics, patients who are malnourished from other causes may also be at risk for developing this disorder.

Traumatic Brain Injury

Concussion dementia can lead to memory problems, and this has been learned in recent years. In some cases, recurrent brain injuries or repeated concussions may contribute to the underlying changes which are identified in Alzheimer’s disease.

Normal Pressure Hydrocephalus

Normal pressure hydrocephalus (NPH) is a condition that causes a person to build up excess fluid in their brain’s ventricles. The job of ventricles are to cushion the area between the brain and spinal cord. There needs to be the exact right amount of fluid in order to cushion that space properly, without putting too much pressure on the brain or spine. That said, fluid can build up excessively, causing additional pressure placed against the brain. Damage occurs as a result of this pressure, and that damage causes dementia symptoms to develop. An estimated 5% of dementia cases are due to NPH, according to John Hopkins Medicine.

In some cases, doctors are able to determine the cause of a patient developing NPH. These cases are usually situations of injury, excessive bleeding, infections, brain tumor, or previous brain surgeries. Some symptoms of normal pressure hydrocephalus include poor balance, changes in one’s mood, memory problems and/or forgetfulness, depression, increase in falls, and loss of bladder or bowel control.

If you think you may have normal pressure hydrocephalus, talk to your doctor as soon as possible. The longer you wait, the more damage this condition cause your brain. NPH is a cause of dementia that can sometimes be cured with surgery, so the sooner you are diagnosed, the better your chances are.

Lewy Body Dementia

Lewy body disease or dementia is caused by Lewy bodies, which are abnormal clumps of certain proteins, which accumulate inside of one’s neurons. Signs of cognitive decline and forgetfulness are the primary features of this condition, yet patients may also develop prominent visual hallucinations, which seem incredibly real to them. There are some patients who develop Lewy body disease and experience symptoms that appear to be Parkinson’s disease, such as slowness or tremors. 

Creutzfeldt-Jakob Disease

Creutzfeldt-Jakob disease is a very rare condition where an abnormal protein leads to the destruction of brain cells and causes dementia. While most cases will occur without any underlying cause, some patients can develop this disease due to a family history of it. Patients may be exposed to the abnormal protein, causing them to develop Creutzfeldt-Jakob disease. For example, Mad Cow disease may be caused by external exposure of this protein. Usually, the condition will progress rapidly, over the course of only a few years, and is often associated with abnormal muscle movements in patients.

Mixed Dementia

Mixed dementia referred to patients who show evidence of two or more types of dementia. Believe it or not, mixed dementia is very common. They usually describe mixed dementia as a patient experiencing the effects of dementia in more than one area of the brain. Alzheimer’s disease and vascular dementia are the most common causes of mixed dementia symptoms.

According to the Jersey Alzheimer’s Association, more than 45% of people diagnosed with dementia, have mixed dementia, but don’t know it. 



When a loved one begins to exhibit signs of a disease which causes symptoms of dementia to develop, it is imperative to have them seen by a specialist as soon as possible. Early-onset Alzheimer’s, short-term memory loss, and other cognitive problems can be prevented, or at least put off for a longer period of time if a diagnosis is made earlier, rather than later. Signs of Alzheimer’s are quite prominent, as are many other diseases that cause dementia, and should be diagnosed as early as possible so that a care plan can be put in place before the patient’s memory is too far gone for them to have a say in their long-term care plan.

Being a caregiver for someone with a form of dementia means more than supervising them. There are financial and legal issues to manage, as well as planning for the future stages of the disease. If caregiver stress becomes too overwhelming, you may have to consider making the transition to a full-time care facility equipped to support the needs of patients with dementia.