Dementia refers to a category of diseases that cause loss of memory and deterioration in other mental functions. Dementia occurs due to physical changes in the brain and is a progressive disease, meaning it gets worse over time. For some people, dementia progresses rapidly, while it takes years to reach an advanced stage for others. The progression of dementia depends greatly on the underlying cause of the dementia. While people will experience the stages of dementia differently, most people with dementia share some of the symptoms.
The symptoms and progression of the disease depend on the type of dementia a person has. Some of the most commonly diagnosed forms of dementia are:
Alzheimer’s disease is the most common form of dementia. It accounts for 60 to 80 percent of cases. It’s usually a slowly progressing disease. The average person lives four to eight years after receiving the diagnosis. Some people may live as many as 20 years after their diagnosis.
Alzheimer’s occurs due to physical changes in the brain, including a buildup of certain proteins and nerve damage.
Dementia with Lewy bodies
Vascular dementia, also known as post-stroke or multi-infarct dementia, accounts for about 10 percent of all cases of dementia. It’s caused by blocked blood vessels. These occur in strokes and other brain injuries.
Parkinson’s disease is a neurodegenerative condition that can produce dementia similar to Alzheimer’s in its later stages. The disease more commonly leads to problems with movement and motor control, but it also can cause dementia in some people.
Frontotemporal dementia refers to a group of dementias that often cause changes in personality and behavior. It can also cause language difficulty. Frontotemporal dementia can occur due to a range of conditions, including Pick’s disease and progressive supranuclear palsy.
Mixed dementia is dementia in which multiple types of dementia-causing brain abnormalities are present. This is most commonly Alzheimer’s and vascular dementia, but it can include other forms of dementia as well.
No single test can determine whether you have dementia. Diagnosis is based on a range of medical tests and your medical history. If you exhibit symptoms of dementia your doctor will perform:
- a physical exam
- a neurological exam
- a mental status tests
- other laboratory tests to rule out other causes of your symptoms
Not all confusion and memory loss indicate dementia, so it’s important to rule out other conditions, such as drug interactions and thyroid problems.
Some common tests used to diagnose dementia include:
Mini-mental state examination (MMSE)
The MMSE is a questionnaire for measuring cognitive impairment. The MMSE uses a 30-point scale and includes questions that test memory, language use and comprehension, and motor skills, among other things. A score of 24 or higher indicates normal cognitive function. While scores 23 and below indicate that you have some degree of cognitive impairment.
This is a short test for helping your doctor diagnose dementia. It involves these three steps:
- They’ll name three words and ask you to repeat them back.
- They’ll ask you to draw a clock.
- They’ll ask you to repeat back the words from the first step.
Clinical dementia rating (CDR)
If your doctor diagnoses you with dementia, they’ll also likely assign a CDR score. This score is based on your performance in these and other tests, as well as your medical history. The scores are as follows:
- A score of 0 is normal.
- A score of 0.5 is very mild dementia.
- A score of 1 is mild dementia.
- A score of 2 is moderate dementia.
- A score of 3 is severe dementia.
Dementia progresses differently in everyone. Many people will experience the symptoms associated with the following stages of Alzheimer’s disease:
Mild cognitive impairment (MCI)
MCI is a condition that can affect older people. Some of these people will go on to develop Alzheimer’s disease. MCI is characterized by losing things often, forgetfulness, and having trouble coming up with words.
People may still be able to function independently in mild dementia. However, they’ll experience memory lapses that affect daily life, such as forgetting words or where things are. Common symptoms of mild dementia include:
- memory loss of recent events
- personality changes, such as becoming more subdued or withdrawn
- getting lost or misplacing objects
- difficulty with problem-solving and complex tasks, such as managing finances
- trouble organizing or expressing thoughts
People experiencing moderate dementia will likely need more assistance in their daily lives. It becomes harder to perform regular daily activities and self-care as dementia progresses. Common symptoms during this stage include:
- increasing confusion or poor judgment
- greater memory loss, including a loss of events in the more distant past
- needing assistance with tasks, such as getting dressed, bathing, and grooming
- significant personality and behavior changes, often caused by agitation and unfounded suspicion
- changes in sleep patterns, such as sleeping during the day and feeling restless at night
People will experience further mental decline as well as worsening physical capabilities once the disease progresses to the point of severe dementia. Severe dementia often can cause:
- a loss of the ability to communicate
- a need for full-time daily assistance with tasks, such as eating and dressing
- a loss of physical capabilities, such as walking, sitting, and holding one’s head up and, eventually, the ability to swallow, to control the bladder, and bowel function
- an increased susceptibility to infections, such as pneumonia
People with dementia will progress through these stages at different speeds and with differing symptoms. If you suspect you may be experiencing early symptoms of dementia, talk to your doctor. While no cure is available for Alzheimer’s and other common dementias, early diagnosis can help people and their families make plans for the future. Early diagnosis also allows people to participate in clinical trials. This helps researchers develop new treatments and eventually find a cure.