Other Types of Dementia

This website mostly deals with Alzheimer's disease and what to do if you are concerned about memory loss. This section, however, deals with other types of dementia, how they affect people, and where to go for further information or help.

Dementia describes a collection of symptoms that are caused by disorders affecting the brain. It is not one specific disease. Dementia affects thinking, behaviour and the ability to perform everyday tasks. Symptoms usually get worse over time.

There are over 100 different diseases that can cause dementia, but most of these are very rare. The most common by far is Alzheimer's disease, which accounts for around two-thirds or more of all cases of dementia.

Other common types of dementia include:

  • Dementia with Lewy bodies
  • Frontotemporal dementia
  • Vascular dementia

Less common causes of dementia include:

  • AIDS related dementia
  • Alcohol related dementia (Korsakoff's syndrome)
  • Creutzfeldt-Jacob disease
  • Huntington's disease
  • Parkinson's disease

Dementia with Lewy bodies

Dementia with Lewy bodies (DLB) is characterised by abnormal protein deposits in the brain, called Lewy bodies after the scientist Friederich H. Lewy who discovered them in 1912. These protein clumps damage brain cells and disrupt normal brain function.

Symptoms of DLB can include problems with attention, concentration, spatial perception, alertness, motivation, planning and reasoning. A core feature of DLB is that these symptoms fluctuate, resulting in day-to-day variability in the person's thinking and behaviour. Memory impairment might not be present in the early stages, but usually occurs as the disease progresses.

Other core features of DLB include visual hallucinations and problems with movement similar to Parkinson's disease (stiffness, slowness of movement and/or tremor).

DLB is the second most common type of dementia after Alzheimer's disease. However, because it shares so many features with Alzheimer's disease and Parkinson's disease, it is often difficult to diagnose. An accurate diagnosis is important to help determine the most appropriate treatment.

If you are concerned that you or someone close to you might be showing signs of DLB, you should discuss your concerns with your doctor.

More information about DLB is available from the following organisations:
The Lewy Body Dementia Association (US)
The Lewy Body Society (UK)

Frontotemporal dementia

Frontotemporal dementia (FTD) is characterised by progressive degeneration of the frontal and/or temporal lobes of the brain. The symptoms and clinical presentation depend on which areas of the brain are damaged. Memory often remains unaffected in FTD, especially in the early stages.

When the frontal lobes are affected first, the main changes are in personality and behaviour, and this is called Behavioural-variant FTD. Common symptoms include changes in mood and behaviour, apathy, loss of empathy, loss of normal inhibitions, changes in eating habits, decline in self-care, and difficulties in reasoning, judgement, planning and organising.

When the temporal lobes are affected first, there is a loss of language skills known as progressive aphasia (aphasia is the loss of ability to produce or understand language). There are two types of FTD where language is impaired – Progressive non-fluent aphasia and Semantic dementia.

In Semantic dementia, the ability to assign meaning to words is gradually lost, causing a decline in language abilities. Reading, spelling, comprehension and expression are usually affected.

In Progressive non-fluent aphasia, the ability to speak fluently is gradually lost. Symptoms may include speaking slowly, using the wrong word, slurred speech, difficulty following conversations, poor spelling, and subtle deficits in problem solving, mental flexibility and decision making.

FTD accounts for around 5-10% of dementia cases. It typically affects people at a younger age than Alzheimer's disease, with onset occurring in the 50s or 60s.

If you are concerned that you or someone close to you might be showing signs of FTD, you should discuss your concerns with your doctor.

More information about FTD is available from the Frontotemporal Dementia Research Group (Frontier).

Vascular dementia

Vascular dementia is caused by damage to blood vessels in the brain. It can be caused by a single stroke, or by several mini-strokes occurring over time.

Vascular dementia is diagnosed when there is evidence of blood vessel disease in the brain and impaired brain function that interferes with daily living. Symptoms of Vascular dementia can begin suddenly after a stroke, or may begin gradually as blood vessel disease worsens.

The symptoms of Vascular dementia vary depending on the location and extent of brain damage. It may affect just one or a few specific thinking functions.

When vascular damage occurs deep in the brain, symptoms can include:

  • Diminished motivation and initiative
  • Loss of insight and apathy
  • Poor planning
  • Poor concentration

When vascular damage affects the cortex (outer layer of the brain), symptoms can include:

  • Changes in sensory and motor functions
  • Language impairment
  • Memory loss
  • Confusion

Heart disease, high blood pressure, high cholesterol, diabetes, heart rhythm abnormalities and smoking all increase the risk of vascular disease and dementia. Treating these and preventing further strokes is very important to prevent Vascular dementia worsening. However, Vascular dementia often coexists with Alzheimer's disease and it can be difficult to know which contributes most to symptoms.

If you are concerned that you or someone close to you might be showing signs of Vascular dementia, you should discuss your concerns with your doctor.

More information about Vascular dementia is available from The Mayo Clinic.