The biggest risk factor for developing dementia is age. Dementia affects both men and women, with women more likely to develop Alzheimer’s disease and men more likely to develop vascular dementia. Most of these cases affect people over the age of 65 years with only 5% of cases reported below this age.
Figures 1-3: MRI brain scan of an individual with biparietal variant of AD / Periventricular white matter ischaemic changes / MRI brain scan of an individual with FTD. Please note the brain atrophy affecting the anterior part of the brain, widening of the Sylvian fissure and the dilated ventricles.
The word ‘dementia’ describes a set of symptoms that may include memory loss and difficulties with thinking, problem-solving or language. For someone with dementia these changes are significant enough to affect their daily life.
Dementia is a global health problem, seen more in developed countries with longer life expectancy. According to the Alzheimer’s Society, in 2015 there were over 850,000 people living with dementia in the UK. It is estimated this number will rise to over one million by 2025. Most of these cases affect people over the age of 65 years with only 5% of cases reported below this age.
Alzheimer’s disease is the most common form of dementia, followed by vascular dementia, dementia with Lewy bodies and frontotemporal dementia.
A person with dementia will have problems with different cognitive tasks (Box 1). They may present unusual behaviours such as asking a question repeatedly, restlessness or agitation. These behaviours can be distressing for both the person and their family.
|BOX 1: COMMON DEMENTIA SYMPTOMS|
A person with dementia can also have changes in their mood: they may become frustrated or irritable, anxious, sad or withdrawn. With some types of dementia, the person may see things that are not there (visual hallucinations).
|BOX 2: NORMAL MEMORY FAILURES|
Dementia is a progressive disease such that the symptoms are likely to get more severe over time. However, the rate of progression can vary significantly between individuals.
Memory problems are common in our busy and distracting day-to-day life. Not all memory failures are signs of dementia (Box 2).
Although everyone experiences such failures, they tend to be more commonly associated with a busy lifestyle, health anxiety, depression or in someone who experienced a severe emotional trauma (dissociative state).
Alzheimer’s disease (AD) is the most common cause of dementia worldwide. AD is caused by small abnormal proteins building up in the brain to form plaques and tangles. This eventually leads to the death of nerve cells and loss of brain tissue.
The clinical hallmark of AD is loss of episodic memory with preservation of autobiographical memory. That means that the person will have good recollection of events that happened a long time ago, but will have frequent memory lapses or difficulty in making new memories. Someone with Alzheimer’s might also develop problems with attention, orientation (losing track of the day or date, getting lost in a familiar place), visuospatial skills (eg. misjudging distances, difficulty navigating in a car park), language (losing track of a conversation, repeating themselves), concentration and planning (difficulty making decisions or carrying out a sequence of tasks such as cooking a meal).
As AD progresses in time, these problems will become more severe. In the later stages of AD someone may become much less aware of what is happening around them and become increasingly frail. Eventually they will need help with all their daily activities. People with AD usually maintain good social façade and hence the problem may not be obvious to spot. Figure 1 is a MRI brain scan of an individual with biparietal variant of AD. Please note the brain atrophy affecting the posterior part of the brain.
Vascular dementia is the second most common form of dementia. It occurs when there is atherosclerosis in the brain vasculature. This can cause problems with memory, thinking or reasoning depending on the part of brain affected. Vascular dementia can arise suddenly after a stroke or can develop progressively in people with risk factors for cerebrovascular disease. Figure 2 is MRI brain scan of an individual with vascular dementia. Please note periventricular white matter ischaemic changes.
Dementia with Lewy bodies
Dementia with Lewy bodies (DLB) is a type of dementia that shares symptoms of both Alzheimer’s disease and Parkinson’s disease. Lewy bodies are tiny deposits of a protein called alpha-synuclein that appear within neuronal cell bodies. As they accumulate within the basal ganglia, they cause movement problems similar to Parkinson’s disease. The clinical hallmark of DLB is visual hallucinations. People with DLB can also experience sleeping problems, constipation, urinary incontinence and autonomic dysfunction. The symptoms tend to get worse over several years, similar to AD. The drugs used in Parkinson’s disease tend to be less effective in DLB. It is important to recognise DLB as antipsychotics can exacerbate hallucinations and cause dystonic reactions and should therefore be avoided.
Frontotemporal dementia (FTD) is one of the less common types of dementia. The frontal lobe of the brain governs an individual’s behaviour, personality, emotions, facilitation and inhibition and problem solving. The temporal lobe deals with the meaning of words and names of objects as well recognising faces and objects.
As Broca’s area is part of the frontal lobe, language dysfunction is a prominent symptom in FTD. FTD is further classified into the behavioural variant, primary progressive aphasia and semantic dementia. Figure 3 is MRI brain scan of an individual with FTD. Please note the brain atrophy affecting the anterior part of the brain, widening of the Sylvian fissure and the dilated ventricles.
Rare causes of dementia include corticobasal degeneration, progressive supranuclear palsy, brain tumours HIV infection, Niemann-Pick type C and Creutzfeldt-Jakob disease (CJD). These tend to occur more in people under the age of 65 years and account for less than 5% of all dementia.
There are a few inherited forms of dementia caused by rare genetic mutations. These include familial Alzheimer’s disease and CADASIL syndrome. Frontotemporal dementia tends to run in families more often than the other types of dementia, with 10%-15% of people affected having a strong family history of the disease.
Memory difficulties and change in personality can sometimes be the presenting feature of brain tumours. Neuro-imaging is an essential investigation in an individual of any age presenting with change in personality, memory or behavioural difficulties. Figure 5 is the MRI brain scan of an individual presenting with symptoms of depression (Figure 4 is an MRI DWI sequence in Creutzfeldt-Jakob disease – please note the cortical ribboning).
There is no single test for dementia. Just as in any other disorder, a detailed history is required both from the patient and from family members. Much can be gained from clinical observations such as an overtly friendly person who is socially disinhibited would suggest the possibility of FTD. Detailed neurological examination can be helpful to pick up signs of vertical gaze palsy, Parkinsonism etc, but neurological examination is generally normal in people with AD.
MRI brain is an invaluable tool in diagnosing dementia. Other specialist tools such as 99mTc- HMPAO SPECT scan or amyloid PET scan for AD diagnosis are currently used mostly in research centres.
Several cognitive assessment tools are available to help with making a diagnosis, such as Mini-Mental State Examination, Montreal Cognitive Assessment or Addenbrooke’s Cognitive examination (ACE-R).
A timely diagnosis can help the person stay well for longer by improving their awareness of the condition and how they and their family can make adjustments to improve their quality of life. A diagnosis helps the person with dementia and their family to get the best treatment, support and plans in place, such as looking at finances, legal issues and making decisions for the present and future.
Although there is no cure for dementia at present, few medicines are available to enhance cognitive function. In mild to moderate Alzheimer’s disease one of the following drugs can be offered: donepezil, rivastigmine or galantamine. These may give temporary help with memory, motivation and concentration. In the moderate or severe stages of Alzheimer’s disease memantine is the drug of choice as it may ease distressing or challenging behaviours and may help with attention and daily living. For a person diagnosed with vascular dementia, drugs targeting the underlying medical condition such as high blood pressure or cholesterol, diabetes and anti-platelets may slow the progression of dementia. Other drugs can be offered to help with sleep disturbance, anxiety or depression.
Counselling and cognitive behavioural therapy can be offered if the person develops depression or anxiety. Cognitive stimulation therapy is a way to keep someone’s mind active and involves doing themed activity sessions over several weeks. Cognitive rehabilitation can help to retain skills and cope better with the challenges of dementia.
Home support ranges from devices such as pill boxes or calendar clocks to practical tips on how to develop routines or break tasks into simpler steps that are easier to follow. It is vital that people with dementia stay as active as they can—physically, mentally and socially. Taking part in meaningful activities is enjoyable and leads to increased confidence and self-esteem.
The biggest risk factor for developing dementia is age. Dementia affects both men and women, with women more likely to develop Alzheimer’s and men more likely to develop vascular dementia. A healthy lifestyle reduces some of that risk. As a general rule, what’s good for the heart is good for the brain. Giving up smoking, eating a healthy diet, regular exercise and reducing alcohol intake are all helpful in protecting the heart and brain. Keeping the mind active by engaging in new activities and learning new skills are also likely to reduce the risk of dementia.
Dr Elena Purcaru
CMT Doctor, Norfolk and Norwich University Hospitals NHS Trust
Dr Muhammad Rafiq
Consultant Neurologist, Norfolk and Norwich University Hospitals NHS Trust
Conflict of interest: none declared