Dementia is a medical condition that affects the brain and is mostly found in the older population, though it can also occur during other stages of adulthood. This article will attempt to explain the disease in more detail, looking at its symptoms, prevalence and possible causes.

Directly translated, dementia means ‘away mind’ and is characterised by a decline in cognitive function more rapid than that which would be expected at the sufferer’s age. It occurs when parts of the brain involved in memory, decision making and language are affected by one or more abnormalities. As previously stated the problem is most common among geriatric patients but can also affect adults (this is known as early-onset dementia and has recently received publicity through Terry Pratchett OBE who at 59 was diagnosed with Alzheimer’s in 2008) and similar symptoms occurring before adulthood are classified as separate ‘developmental disorders’. This decline in ability can take many forms affecting memory, attention, language and problem solving with higher mental functions usually affected first.

While symptoms vary across incidences and individual patients, they will often be observed as memory difficulties, general confusion and disorientation with sufferers getting lost and being unsure as to the date, who people are or even who they are themselves. Also exhibited in some cases are changes of personality, restlessness, irritability, hallucinations, language difficulties, verbal outbursts and slurred speech. These effects are generally irreversible, though in less than ten percent of cases they may be curable through treatment (dementia is not to be confused with the short-term ‘delirium’ which has similar symptoms).

Diagnosis will require consulting a specialist such as a geriatric psychiatrist, neurologist, neuropsychologist etc who will listen to the patient’s symptoms and experience and pattern of decline. There are also several measures that can test for dementia with fair reliability such as the Mini-Mental State Examination and the Abbreviated Mental Test Score. Report scales designed to be filled in by relatives or carers such as the Informant Questionnaire on Cognitive Decline in the Elderly also exist and can be used in conjunction with those mentioned above. Poor performance on these or similar scales suggests the existence of a problem and will lead to more in-depth neurological testing. Blood tests can be carried out to test for treatable causes such as vitamin deficiencies or infections. Additionally, patients may undergo a CT scan or MRI. These are not sensitive enough however to detect the metabolic changes in patients who don’t also demonstrate neurological problems in neurological exams, though it can help distinguish between certain types of dementias. Functional neuroimaging techniques SPECT and PET have also been shown to be useful in this capacity.

Symptoms of dementia vary largely across many subtypes of which Alzheimer’s and Vascular dementia are the most common. The over 50 different forms of dementia are sometimes categorised under two headings – ‘cortical’ and ‘sub cortical’, with Alzheimer’s and Vascular falling under the former and dementia caused by Huntington’s disease or Syphilis falling under the latter. This distinction is controversial however and there is debate as to its usefulness and accuracy (Huber et al., 1986). It is thought however that subcortical syndromes involve less damage to the memory and cognitive skills and that only cortical cases lead to aphasia, agnosia and apraxia. A selection of the most common forms of dementia will be discussed in detail over the following few paragraphs with particular attention to the neuropathology of each.

Mack LeMouse

Copyrighted material; do not reprint without permission.

 

View all articles by Mack LeMouse