What are the types and stages of dementia?

What are the types and stages of dementia?

What are the types and stages of dementia?

Types of dementia

The types of dementia are divided into several classifications of the condition. Dementia is classified by the following criteria:

  • Area of the brain affected
  • If the condition is progressive
  • If the dementia is the result of another disorder (primary and secondary)


The diseases mentioned in the types of dementia below are further explained later on in the article.

The types of dementia are as follows:

Cortical Dementias

These types of dementias occur due to issues with the cerebral cortex, the brain’s outer layer. The cortex plays a vital role in language and memory. Those with cortical dementias will typically experience severe memory issues and loss and struggle to remember words and find it difficult to understand language. Alzheimer’s disease (an irreversible brain disorder) and Creutzfeldt-Jakob (a rare and degenerative brain disorder that leads to dementia and can be fatal in some cases) are two different types of cortical dementia.

Subcortical Dementias

These types of dementias occur due to an issue with the area of the brain that is situated below the cortex. Subcortical dementias tend to affect one’s ability to think quickly and start activities. Issues with language and forgetfulness are not normally experienced in those with this type of dementia. Huntington’s disease (which leads to the degeneration of nerve cells), HIV (which interferes with the immune system) and Parkinson’s disease (a disorder of the central nervous system) have been known to cause subcortical dementias.

Progressive Dementia

These types of dementias will get worse over time and the patients tend to eventually lose more and more of their ability to function. Alzheimer’s disease, vascular dementia (brain damage caused by strokes), frontotemporal dementia (a group of conditions that result in the progressive damage of the brain) and Lewy body dementia are types of dementia that are progressive.

Primary Dementia

Patients with primary dementia will only show the dementia symptoms. Alzheimer’s disease accounts for 50 to 70 percent of primary dementia cases as it is a form of this kind of dementia.

Secondary Dementia

These types of dementia develop as peripheral conditions to an already existing condition or illness. Multiple sclerosis (a disease of the central nervous system), brain infections and progressive supranuclear palsy (which affects movement and speech) are examples of certain conditions that can result in secondary dementias developing.  

Stages of dementia

The dementia stages are grouped into categories of mild, moderate and severe. It is possible for patients to be categorised into two different stages at one time, this is, however, dependent on their symptoms. It is not possible to use the stages of dementia to predict how a patient’s symptoms will progress. Every person will experience dementia differently, their experience is dependent on the cause of their dementia.

Doctors will normally determine the stage of the patient’s dementia by asking several questions of the patient's caregiver or the patient themself if they are able to understand and answer these. A screening tool known as the Mini-Mental Stage Examination is used to determine the cognitive decline on a scale of zero to 30. Diagnosing the stage of dementia may aid in the doctor creating a plan of treatment.

Stages of dementia may be characterised as follows:

No Impairment

The person is able to function on their own and there are no signs that are obvious at this point.

Very Mild Impairment

Forgetfulness that is often associated with ageing is evident at this stage. However, any other symptoms are not yet obvious.

Mild Impairment

In this stage, the person is still able to complete daily tasks and go about their daily routines. Symptoms that become evident in this stage are:

  • Losing items
  • Memory loss
  • Forgetfulness
  • Confusion when driving
  • Loss of concentration
  • Issues when managing medications

Moderate Impairment

Issues with performing everyday tasks are evident here. Kinds of symptoms that become present are:

  • Difficulty holding in urine (i.e. bladder control)
  • Social withdrawal is increased
  • Difficulty in using or finding the right words
  • Difficulty in completing mental mathematic problems
  • Increased forgetfulness and memory loss

Moderately Severe Impairment

At this stage, the patient may begin to need daily assistance when completing tasks. Symptoms of this stage are the following:

  • Confusion when driving and following directions
  • Memory loss is increasing
  • Issues when completing less challenging problem solving
  • Needing assistance in picking an appropriate wardrobe for the day or special events

Severe Impairment

At this stage, the patient will need even more assistance when completing daily tasks and following a routine. Symptoms of this stage include the following:

  • Battling to sleep
  • Personality changes – including hallucinations or paranoia
  • Needing help in going to the toilet
  • Being unable to remember the names of caregivers, friends or loves ones
  • Getting lost easily
  • Battling to drive
  • Needing help in getting dressed

Very Severe Impairment

It is at this stage that the patient will need 24/7 care from either a loved one or a caregiver. Symptoms of this stage have been known to include the following:

  • Losing the ability to communicate effectively
  • Losing spatial awareness
  • Needing assistance when eating
  • Being unable to control bladder and bowel movements
  • Losing muscle control in walking, facial expressions, sitting or even swallowing
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