What is dementia?
Dementia is a generic term for various disorders associated with memory, communication and thinking problems which interfere to a significant extent with a person’s daily activities. It is not a normal part of aging and is distinguishable from the mild cognitive impairment, usually noticeable short-term memory loss, from which 5% to 20% of older people are thought to suffer but which does not interfere with their independence or daily life. A common criterion for dementia is that two or more core mental functions must be impaired.
What causes dementia?
Dementias are caused by the death of nerve cells in the brain.
Symptoms and types of dementia
About 10% of people over 65 years of age are thought have dementia but by the age of 85 this increases to over 30%. The following list of signs indicative of dementia has been published by the American Academy of Family Physicians:
- Recent memory loss – a sign of this might be asking the same question repeatedly, forgetting about already asking it.
- Difficulty completing familiar tasks – for example, making a drink or cooking a meal, but forgetting and leaving it.
- Problems communicating – difficulty with language by forgetting simple words or using the wrong ones.
- Disorientation – with time and place, getting lost on a previously familiar street close to home, for example, and forgetting how they got there or would get home again.
- Poor judgment – the AAFP says: “Even a well person might get distracted and forget to watch a child for a little while. People with dementia, however, might forget all about the child and just leave the house for the day.”
- Problems with abstract thinking – for example, dealing with money.
- Misplacing things – including putting them in the wrong places and forgetting about doing this.
- Mood changes – unlike those we all have, swinging quickly through a set of moods.
- Personality changes – becoming irritable, suspicious or fearful, for example.
- Loss of initiative – showing less interest in starting something or going somewhere.
The main types of dementia are:
This disease accounts for between 60% and 80% of dementia cases. Although the majority of people with Alzheimer’s are over 65 the early onset type often occurs when people are in their 40s or 50s. It is a progressive disease which initially affects the part of the brain concerned with learning and results in short-term memory problems. Later the symptoms become increasingly severe and can include serious memory loss, difficulty speaking, confusion about events, mood changes and mobility problems.
Alzheimer’s disease is thought to be caused by protein abnormalities in the brain – the accumulation of plaques between dying cells and the disintegration of tau protein tangles within the cells. Although treatments are available for the symptoms currently there is no cure and death usually occurs within 4 to 20 years.
Further information links:
This general term relates to memory and thinking difficulties caused by strokes and other injuries or conditions which cause damage to brain cells by impairing the blood circulation and hence the oxygen supply. Changes in behaviour, memory, speed of thought and other symptoms similar to those occurring in other forms of dementia vary from person to person depending on the extent of the brain damage as does the rate of progression.
Further information links:
Dementia with Lewy bodies
At about 10% this is the second most prevalent type of progressive dementia. Lewy bodies are small deposits of alpha-synuclein protein in the nerve cells concerned with memory, thinking and movement. Some of the symptoms may be similar to those Parkinson’s disease (e.g. slow movement and rigidity) and Alzheimer’s disease (e.g. memory and judgement problems). Hallucinations, feelings of persecution, falls, and sleep and attention disorders are typical features. Initially the symptoms can be difficult to detect but they gradually get worse and eventually intensive nursing might be required. Treating the disease is difficult and at present there is no cure.
Further information links:
Frontotemporal Dementia (FTD)
After Alzheimer’s disease, vascular dementia and Dementia with Lewy Bodies, FTD is believed to be the 4th most common type of dementia. Together these four types account for about 95% of all dementia cases.
FTD is a group of disorders caused by progressive cell degeneration in the frontal or temporal lobes of the brain and comprises the following three which have increasingly common features as they progress:-
- Behavioural Variant Frontotemporal Dementia (formerly known as Pick’s disease)
Symptoms – Initially signs of depression progressing to a loss of inhibitions, a loss of social skills and selfish, inappropriate and repetitive or compulsive behaviour.
- Primary progressive aphasia
Initially language is affected and behaviour later. The 2 main types and there symptoms are:-
(a) Semantic dementia – whilst speaking easily people increasingly use general terms and cease to understand the meaning of words.
(b) Progressive nonfluent aphasia – speech becomes hesitant and ungrammatical; some loss of ability to read and write
3. FTD movement disorders
Some muscle functions are affected which can cause problems relating to behaviour and language. The two main types are:-
(a) Corticobasal degeneration – characterised by lack of coordination, muscle rigidity, spasms and shakiness.
(b) Progressive supranuclear palsy – personified by balance problems, falls, upper body muscle stiffness and abnormal eye movements.
FTD is often diagnosed at a younger age, between 45 and 65, than Alzheimer’s disease and tends to run in families. Several genes are known to be linked to FTD and the abnormal protein deposits in brain cells which are associated with it.
Further information links:
More than 10% of people with dementia probably have more than one type – usually a combination of Alzheimer’s disease and vascular dementia but Lewy body dementia might also be present.
Up to 5% of dementias can be associated with other diseases such as:-
Prion diseases – notably Classic and Variant Creutzfeldt-Jakob Disease
Parkinson’s disease with Lewy bodies
A World Dementia Council was set up in 2014 to lead international efforts to develop new treatments and better care for people with dementia or at risk of dementia. In 2012 the US President announced a national plan with the aim of preventing and effectively treating Alzheimer’s disease and the other major types of dementia by 2025. Research is focusing on the clinical trials of new drugs, genetics, imaging, proteins, stem cells, exercise, sleep and international cooperation.
In the UK substantial funding is being invested in dementia research by the Government, Medical Research Council, Alzheimer’s Research UK, major pharmaceutical companies and other organisations. Alzheimer’s Research UK alone is funding over 700 researchers at 15 centres.
Research at the University of Nottingham & the Queen’s Medical Centre
Extensive research has been carried out at Nottingham for many years with ancillary funding and other types of support from the Neuroscience Support Group at the QMC. The March 2008 bulletin of the Society for Experimental Biology says regarding our Chairman “ Professor Mayer has a special interest in the importance of the ubiquitin-proteasome system for human chronic neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, and dementia with Lewy bodies (the second most common cause of cognitive decline in the elderly, discovered in Nottingham), motor neurone disease and all the other diseases including Huntington’s disease and frontotemporal dementias. “All these diseases are characterised neuropathologically by the occurrence of inclusion bodies (Lewy bodies) in neurones, containing ubiquitinated proteins”, says Professor Mayer”. More recently Professor Kevin Morgan and his team (see our Projects page) have directly contributed to the discovery of 21 of the 22 genes known to be linked with Alzheimer’s disease. Other examples of current or recent research at Nottingham are:
Professor Philip Bath – Vascular dementia : A clinical trial to test the effect of drugs that lower blood pressure and cholesterol on stroke patients at risk of developing dementia
Dr Virginie Sottile – Dementia : A project to investigate if stem cells within bone marrow could form brain cells which could lead to new therapies for dementia in future