I am curious about dementia and would like to learn more

What is dementia?

Dementia is not a specific disease but is an umbrella term for a variety of conditions that cause impairment to the brain. Impaired ability can impact one’s ability to remember, think, or make decisions, can affect language and interfere with normal day-to-day responsibilities. Dementia most commonly affects older people; it is not, however, considered a part of normal aging. Though dementia generally involves memory loss, memory loss has different causes. Having memory loss alone doesn’t mean an individual has dementia, although it’s often one of the early signs of the condition.

There are many types of dementia. Alzheimer’s dementia is the most common cause. Vascular dementia, dementia with Lewy bodies and Frontotemporal dementia are other causes. Some people may be diagnosed with dementia and it may not be possible to confirm if it is Alzheimer’s or another cause of dementia. In some instances, a person can present with a mix of types of dementia. Autopsy studies of the brains of older people who had dementia have shown that their dementia may have had several causes, such as Alzheimer’s disease, vascular dementia and Lewy body dementia. Studies are ongoing to determine how having mixed dementia affects symptoms and treatments.

Understanding dementia

Types of Dementia

There are many diseases that may cause dementia. The most common causes include Alzheimer’s disease, vascular dementia, dementia with Lewy bodies and Frontotemporal dementia.


Dementia symptoms vary depending on the cause, but common signs and symptoms include:

Cognitive changes

  • Memory loss, which is usually noticed by someone else
  • Difficulty communicating or finding words
  • Difficulty with visual and spatial abilities, such as getting lost while driving
  • Difficulty reasoning or problem-solving
  • Difficulty handling complex tasks
  • Difficulty with planning and organizing
  • Difficulty with coordination and motor functions
  • Confusion and disorientation

Psychological changes

  • Personality changes
  • Depression
  • Anxiety
  • Inappropriate behavior
  • Paranoia
  • Agitation
  • Hallucinations

Alzheimer’s disease

Alzheimer’s disease is the most common cause of dementia accounting for some 50% of cases. Although not all causes of Alzheimer’s disease are known it is associated with the build-up of proteins (called beta-amyloid and tau) in the brain which form clumps and tangles in and around the brain’s nerve cells (called neurons) that interfere with normal brain functioning. A small percentage of Alzheimer’s disease is related to gene mutation which can be inherited.

Short term memory loss is often one of the first symptoms of this disease; however there are a range of early signs and symptoms including

  • Getting stuck for words;
  • Misplacing things regularly;
  • Losing track of time;
  • Changes in mood and behaviour and;
  • Difficulty in finding the way, even in familiar places.

It is important to remember that symptoms vary from person to person as everyone’s experience with the disease is unique.

Vascular dementia

This type of dementia, the second most common form of dementia, is caused by damage to the vessels that supply blood to your brain. Blood vessel problems can cause small strokes (multi-infarct dementia) or small vessel disease (subcortical dementia).

As Multi-infarct dementia is caused by small strokes it is commonly described as being incremental in nature rather than gradual in progression. An affected individual worsens in steps as small strokes occur. Subcortical dementia is another type of vascular dementia and is caused by very small blood vessels that are in the inner parts of the brain.

The most common signs of vascular dementia include difficulties with communication, concentrating, problem-solving, slowed thinking, and loss of focus and organization. These tend to be more noticeable than memory loss.

Dementia with Lewy bodies

Dementia with Lewy bodies is a type of dementia that shares characteristics with both Alzheimer’s disease and Parkinson’s disease. Lewy bodies are abnormal balloon like clumps of protein that have been found in the brains of people with Lewy body dementia, Alzheimer’s disease and Parkinson’s disease.

Like Alzheimer’s disease symptoms progress gradually over several years. The person will experience many of the signs and symptoms of Alzheimer’s disease and may also experience:

  • disturbed sleep patterns – acting out one’s dreams in sleep
  • seeing things that aren’t there (visual hallucinations)
  • uncoordinated or slow movement or muscle stiffness (shuffling while walking)
  • tremors, and rigidity (parkinsonism)
  • sleepiness during the day whilst not sleeping at night

Frontotemporal dementia

Frontotemporal dementia, is a group of diseases associated with the breakdown of nerve cells and their connections in the front and sides of the brain (areas behind the ear). These areas are associated with personality, behaviour and language. This dementia often may cause a person to:

  • say and do things in inappropriate situations
  • lose their sense of sympathy or empathy
  • lose interest in things or people
  • carry out repetitive, compulsive behaviours
  • use language incorrectly e.g. errors in grammar, slow, hesitant speech or difficulty finding the right word

It is more common in younger people (45-65) but can also develop in older individuals. The progression of this dementia is unpredictable and in the later stages symptoms are similar to those of Alzheimer’s disease.

Early Onset Dementia

Early onset (also called young-onset) Alzheimer’s is an uncommon form of dementia that affects people younger than age 65. About 5% to 6% of people with Alzheimer’s disease develop symptoms before age 65.

Doctors don’t usually suspect dementia in younger people. The process of getting a diagnosis can therefore be difficult. Experts don’t fully know why some people get the disease at a younger age than others do. People who develop dementia at a younger age may have a strong family history of dementia. Genetics may have a role in the development of their condition but for most people the cause is not related to any single genetic mutation.

It’s important to understand that a family history of Alzheimer’s disease does not necessarily mean that there is a gene mutation present in an individual or family. It is possible to develop young-onset Alzheimer’s disease from causes other than changes in these three genes. Early onset dementia can affect those with another health condition such as Parkinson’s disease, multiple sclerosis, Huntington’s disease, HIV or AIDS.

When to see a doctor

See a doctor if you or a loved one has memory problems or other dementia symptoms. Some treatable medical conditions can cause dementia symptoms, so it’s important to determine the cause.

Intellectual Disability and Dementia

People with an intellectual disability, particularly people with Down syndrome, are at increased risk of developing dementia as they age.  This is due to their genetic predisposition.

Diagnosing dementia in people with an intellectual disability is complex because the person may already have difficulties in areas such as memory, language and being independent with self care needs.

The National Intellectual Disability Memory Service (NIDMS) is a centre of excellence in proactive dementia assessment and diagnosis for people with an intellectual disability (ID), particularly supporting people with Down syndrome given their increased genetic risk for dementia.

The NIDMS provides access to a Brain Health Clinic and to specialist assessment and comprehensive diagnostic work-up for memory concerns. They also have a wide range of support materials available. See the flyer opposite for further information.

Symptoms and Progression of Dementia

Early signs factsheet

Often the early signs of dementia may be difficult to detect. Some people experience changes in their short term memory early on, for others changes to mood or to language may be the early signs. Each person’s experience with dementia is unique. Dementia may last many years, sometimes progressing faster, sometimes more slowly. This means that no one can tell you exactly how the condition will progress and how long a person can live with dementia.

It can be stressful not getting direct answers to your questions but can be helpful to think about dementia as a condition that progresses in stages. Click here for further information on the symptoms and progression of dementia.

Getting a diagnosis

Diagnosis of dementia

It is important to note that memory lapses don’t always mean dementia. Other conditions may mirror the symptoms of dementia making it important to get an evaluation of the symptoms being experienced. There is no single test to determine if someone has dementia. The journey towards diagnosis usually begins with a consultation with your GP who will discuss the indications of memory loss concerning you. The first priority is to rule out other possible causes of your memory complaints. Doctors diagnose Alzheimer’s and other types of dementia based on a careful medical history, a physical examination, laboratory tests, and the characteristic changes in thinking, day-to-day function and behaviour associated with each type.

The GP may make an initial diagnosis of dementia and then refer you to a hospital-based consultant or memory service for a full assessment to identify the cause of your symptoms. It can be difficult to determine the exact type of dementia because the symptoms and brain changes of different dementias can overlap. If you are over 65, referral may be to a geriatric medicine specialist or a later life psychiatrist. If you are under 65 you may be referred to a neurologist – a doctor with expertise in disorders of the brain.
Click here for further information on taking the first steps in obtaining a diagnosis.

How can I get involved in research?

TeamUp for Dementia Research

TeamUp for Dementia Research is a service, coordinated by the Alzheimer Society of Ireland, where people living with dementia and their families can register their interest in participating in dementia research.

TeamUp connects you with researchers who are conducting studies in the area of dementia (e.g. prevention, diagnosis, treatment, care, cure).

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Dementia Research Advisory Team (PPI)

The Dementia Research Advisory Team is a group coordinated by the Alzheimer Society of Ireland (ASI). Its member’s comprise people living with dementia and carers/supporters who are involved in dementia research as co-researchers. These Experts by Experience influence, advise, and work with researchers across Ireland. In addition team members come together 3-4 times per year for capacity building workshops. Members also contribute to ASI’s research funding decisions and review process for tenders.

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Dementia Carers Campaign Network

The Dementia Carers Campaign Network (DCCN), facilitated by the Alzheimer Society of Ireland, is a group of people who have experience caring for a loved one with dementia. The DCCN aims to be a voice of, and for, dementia carers in Ireland and to raise awareness of issues affecting families living with dementia. All members of the DCCN are volunteer advocates, they meet several a year to discuss issues which affect them, and to organise campaigns and lobby for change.

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PPI Ignite Network

The PPI Ignite Network promotea public and patient involvement (PPI) in health and social care research in Ireland by getting public and patients involved in planning and doing research from start to finish and helping tell the public about the results of research. PPI Ignite work with their partners, including DTI, to develop engagement opportunities which will allow researchers and members of the public, patients or carers who share an interest in a research topic to connect up with each other.

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