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What is Alzheimer’s Disease?
According to the Center for Disease Control, Alzheimer’s disease is a common cause of dementia causing as many as 50 to 70% of all dementia cases. In fact, Alzheimer’s is a very specific form of dementia. Symptoms of Alzheimer’s include impaired thought, impaired speech, and confusion. Doctors use a variety of screenings to determine the cause of dementia including blood tests, mental status evaluations and brain scans.
Symptoms of Alzheimer’s
The symptoms of Alzheimer’s disease are generally mild to start with, but they get worse over time and start to interfere with daily life.
There are some common symptoms of Alzheimer’s disease, but it is important to remember that everyone is unique. Two people with Alzheimer’s are unlikely to experience the condition in exactly the same way.
For most people with Alzheimer’s, the earliest symptoms are memory lapses. In particular, they may have difficulty recalling recent events and learning new information. These symptoms occur because the early damage in Alzheimer’s is usually to a part of the brain called the hippocampus, which has a central role in day-to-day memory. Memory for life events that happened a long time ago is often unaffected in the early stages of the disease.
Memory loss due to Alzheimer’s disease increasingly interferes with daily life as the condition progresses. The person may:
- lose items (eg keys, glasses) around the house
- struggle to find the right word in a conversation or forget someone’s name
- forget about recent conversations or events
- get lost in a familiar place or on a familiar journey
- forget appointments or anniversaries.
Although memory difficulties are usually the earliest symptoms of Alzheimer’s, someone with the disease will also have or go on to develop problems with other aspects of thinking, reasoning, perception or communication. They might have difficulties with:
- language: struggling to follow a conversation or repeating themselves
- visuospatial skills: problems judging distance or seeing objects in three dimensions; navigating stairs or parking the car become much harder
- concentrating, planning or organising: difficulties making decisions, solving problems or carrying out a sequence of tasks (eg cooking a meal)
- orientation: becoming confused or losing track of the day or date.
A person in the earlier stages of Alzheimer’s will often have changes in their mood. They may become anxious, irritable or depressed. Many people become withdrawn and lose interest in activities and hobbies.
Causes of Alzheimer’s
Like all types of dementia, Alzheimer’s is caused by brain cell death. It is a neurodegenerative disease, which means there is progressive brain cell death that happens over a course of time.
The total brain size shrinks with Alzheimer’s – the tissue has progressively fewer nerve cells and connections.
How common is Alzheimer’s disease?
In the US, the most recent census has enabled researchers to give estimates of how many people have Alzheimer’s disease. In 2010, some 4.7 million people of 65 years of age and older were living with Alzheimer’s disease in the US.1
The 2013 statistical report from the Alzheimer’s Association gives a proportion of the population affected – just over a tenth of people in the over-65 age group have the disease in the US. In the over-85s, the proportion goes up to about a third.2
As our dementia page outlines, there is a handful of different types, but Alzheimer’s disease is the problem behind most cases of memory loss and cognitive decline:2
- The Alzheimer’s Association says it accounts for between 60% and 80% of all cases of dementia.
Vascular dementia, which is caused by stroke not Alzheimer’s, is the second most common type of dementia.
Who is affected Alzheimer’s disease?
Alzheimer’s disease is most common in people over the age of 65, and affects slightly more women than men.
The risk of Alzheimer’s disease and other types of dementia increases with age, affecting an estimated 1 in 14 people over the age of 65 and 1 in every 6 people over the age of 80.
However, around 1 in every 20 cases of Alzheimer’s disease affects people aged 40 to 65.
What is Dementia?
Dementia is not a single disease in itself, but a general term to describe symptoms such as impairments to memory, communication, and thinking.
While the likelihood of having dementia increases with age, it is not a normal part of aging.
Light cognitive impairments, such as poorer short-term memory, can happen as a normal part of aging. This is known as age-related cognitive decline rather than dementia because it does not cause significant problems.
Dementia describes two or more types of symptom that are severe enough to affect daily activities.
An analysis of the most recent census estimates that 4.7 million people aged 65 years or older in the United States were living with Alzheimer’s disease in 2010. The Alzheimer’s Association estimates that:
- Just over a tenth of people aged 65 years or more have Alzheimer’s disease
- This proportion rises to about a third of people aged 85 and older
- Alzheimer’s accounts for 60-80 percent of all cases of dementia
Causes of Dementia
Dementia usually occurs in older age. It is rare in people under age 60. The risk of dementia increases as a person gets older.
Most types of dementia are nonreversible (degenerative). Nonreversible means the changes in the brain that are causing the dementia cannot be stopped or turned back. Alzheimer disease is the most common type of dementia.
Another common type of dementia is vascular dementia. It is caused by many small strokes.
Lewy body disease is a common cause of dementia in the elderly. People with this condition have abnormal protein structures in certain areas of the brain.
The following medical conditions can also lead to dementia:
- Huntington disease
- Brain injury
- Multiple sclerosis
- Infections such as HIV/AIDS, syphilis, and Lyme disease
- Parkinson disease
- Pick disease
- Progressive supranuclear palsy
Some causes of dementia may be stopped or reversed if they are found soon enough, including:
- Brain injury
- Brain tumors
- Chronic alcohol abuse
- Changes in blood sugar, sodium, and calcium levels (dementia due to metabolic causes)
- Low vitamin B12 level
- Normal pressure hydrocephalus
- Use of certain medicines, including cimetidine and some cholesterol drugs
Symptoms of Dementia
Dementia symptoms vary depending on the cause, but common signs and symptoms include:
- Memory loss, which is usually noticed by a spouse or someone else
- Difficulty communicating or finding words
- Difficulty reasoning or problem-solving
- Difficulty handling complex tasks
- Difficulty with planning and organizing
- Difficulty with coordination and motor functions
- Confusion and disorientation
- Personality changes
- Inappropriate behavior
How common is Dementia?
According to the Alzheimer’s Society there are around 800,000 people in the UK with dementia. One in three people over 65 will develop dementia, and two-thirds of people with dementia are women.
The number of people with dementia is increasing because people are living longer. It is estimated that by 2021, the number of people with dementia in the UK will have increased to around 1 million.
Difference Between Alzheimer’s and Dementia
When a person is diagnosed with dementia, they are being diagnosed with a set of symptoms. This is similar to someone who has a sore throat. Their throat is sore but it is not known what is causing that particular symptom. It could be allergies, strep throat, or a common cold. Similarly, when someone has dementia they are experiencing symptoms without being told what is causing those symptoms.
Another major difference between the two is that Alzheimer’s is not a reversible disease. It is degenerative and incurable at this time. Some forms of dementia, such as a drug interaction or a vitamin deficiency, are actually reversible or temporary.
Once a cause of dementia is found appropriate treatment and counseling can begin. Until a proper diagnosis is made, the best approach to any dementia is engagement, communication and loving care.