What is frontal lobe dementia?
The frontal lobes of the brain are located as the name suggests at the front of the brain. Loosely speaking, it contains what we call the higher functions of the brain. These are the areas of the brain responsible for emotions, understanding, speech; some types of movement, planning and judgement in other words the things which make you a person, and personality. Like all dementias the people who develop symptoms face a slow loss of self and those who care for them, losing the person they care for by slow degrees.
Frontal lobe dementia is also known as frontotemporal dementia (FTD), or frontotemporal degeneration, it is an overarching term for several categories of a loss of brain function. The changes to the brain are caused by an abnormal build-up of tau proteins, which stop the brain cells from functioning properly, so they die. In frontal lobe dementia parts of the frontal and temporal lobes of the brain are damaged. It was previously known as ‘Pick’s disease’ after the doctor Arnold Pick who identified and first documented the symptoms in a patient over a hundred years’ ago in 1892.
Unlike the most widely diagnosed form of dementia, Alzheimer’s disease, frontal lobe dementia occurs at a much younger age and is partly genetic. That means while there is no certainty that if you have had a close blood relative with FLD you will get it too, your chances of developing it are much higher than for other members of the population.
There are several genes that appear to link with frontal lobe dementia, which ties in with a family history of the disease being the only known risk factor. Approximately 15% of people diagnosed have a family member with the disease. However there is no single cause for the disease.
There are three predominant forms of frontal lobe dementia:
- Behavioural variant frontotemporal dementia, affecting approximately two thirds of people with the disease. Besides changes in behaviour, people with this form will find it difficult to control, plan or organise their actions.
- Progressive non-fluent aphasia, where the areas controlling speech in the temporal lobe are damaged. People will find it difficult to speak and eventually become mute.
- Semantic dementia, where the areas of the temporal lobe responsible for the understanding of language and knowledge are damaged. People will have problems with thinking and language.
In approximately 20% of cases, there is frontotemporal dementia also associated with motor neurone disease (MND), where in addition the nerve cells that control voluntary movement in the body are destroyed, resulting in people with the disease gradually losing the ability to move. Professor Steven Hawking is perhaps the most well-known personality to have developed a form of MND.
Signs and symptoms?
As with other forms of dementia, frontal lobe dementia is progressive, increasingly affecting behaviour and emotion, language, and ability to think or problem solve. People with the disease may have problems with speaking or understanding speech. Depending upon which parts of the frontal lobe are damaged first they may become very enthusiastic or display apathy. When the centres responsible for control of decision making are affected first they may also display inappropriate behaviour. There are other causes of these changes which are not FTL dementia related, but these are usually a result of injury or trauma which have affected the same part of the brain, the most well-known case being Phineas Gage a railway engineer who suffered left frontal lobe damage as a result of being impaled on a spike following an explosion.
NHS Choices lists the following signs for frontotemporal dementia:
- inappropriate behaviour in public
- loss of inhibitions
- overeating, a change in food preferences (such as suddenly liking sweet foods), poor table manners
- neglect of personal hygiene
- repetitive or obsessional behaviours, such as humming, hand-rubbing and foot-tapping, or complex routines such as walking exactly the same route repetitively
- seeming more selfish
- inability to empathise with others, seeming cold and uncaring
- being tactless or rude
- being less or more outgoing than in the past
- being lethargic, lacking enthusiasm
Whilst the tau protein build-up and damage seen at post mortem, a magnetic resonance imaging scan (MRI) will show the shrinkage in the lobes to assist diagnosis. Diagnosis is normally made after a series of physical and mental assessments, and diagnostic tests to rule out other causes.
Life expectancy and Treatment
About 10 – 15% of dementia cases are thought to be frontal lobe dementia, the disease affecting 1 in 5000 of the population. However in those under 65 it is believed to be 20 – 50% of cases. Onset of frontal lobe dementia is normally identified when the patient is between 45 and 65 years of age, although it has been seen in people aged 20 to 30 years of age. Only 10% of cases are identified in those 70 years and over.
The disease takes from three to ten years to progress, although there are instances of much shorter or longer times. The average life expectancy of a person diagnosed with frontal lobe dementia is eight years. Approximately 50% of deaths are as a result of pneumonia, following complications associated with inability of the person to move or care for themselves.
As with other forms of dementia there is no current cure for the disease, but there are a range of treatments that can help to manage and deal with the symptoms, and to help people to regain some of their lost functions.
These include drugs such as SSRI antidepressants to help control the symptoms like obsession, over-eating and depression. Antipsychotics may be given to address challenging and inappropriate behaviours. Psychological treatments such as cognitive stimulation and behavioural therapy can help maintain memory function address anxiety. Rehabilitative practices such as, occupational therapy, physiotherapy and speech therapy can help the brain to learn new ways to do things.
At the time of writing, the best hope for a cure or enhanced length of life, lies with stem cell research but this is still at an early stage and a long way from clinical trials.
People with the disease will need a range of services as it progresses and a multi-disciplinary care plan needs to be established soon after diagnosis and revised as the person experiences more symptoms.
The distinction between the various forms of the disease becomes less obvious as the disease progresses. For example all people with the disease will lose some or all of their speech. In the latter stages the symptoms are very similar to those of Alzheimer’s disease and the person will need full time care.