Dementia
Dementia is a syndrome, often associated with neurodegenerative diseases such as Alzheimer's. It is characterized by a general decline in cognitive abilities that affects a person's ability to perform everyday activities. This typically involves problems with memory, thinking, behavior, and motor control. Aside from memory impairment and a disruption in thought patterns, the most common symptoms include emotional problems, difficulties with language, and decreased motivation. The symptoms may be described as occurring in a continuum over several stages. Dementia is an incurable, progressive neurocognitive disorder, with varying degrees of severity ranging from mild to major. Many forms or subtypes exist within this broad category. The condition has a significant effect on the individual, their caregivers, and their social relationships in general. Dementia is not the same as age-related decline in cognition and memory, with no change in intelligence. The most common form of dementia is Alzheimer's. Dementia can be caused by brain injuries and stroke. It has also been described as a spectrum of disorders with subtypes based on which known disorder caused its development.
The course of dementia is often described in three major stages: early, middle, and late. These stages show a pattern of progressive cognitive and functional impairment. The Global Deterioration Scale uses seven stages in the development of dementia, with mild dementia only appearing as stage 4. Other scales used are the Brief Cognitive Rating Scale, Clinical Dementia Rating, and the Functional Assessment Staging Tool. Pre-dementia includes a pre-clinical stage before the onset of symptoms and prodromal early clinical symptoms. Sensory dysfunction, most notably the loss of the sense of smell, is claimed for the pre-clinical stage. This may precede the first clinical signs of dementia by up to ten years. Prodromal pre-dementia states considered include mild cognitive impairment and mild behavioral impairment. Signs and symptoms at the prodromal stage may be subtle, and the early signs often become apparent only in hindsight. In mild cognitive impairment that progresses to a dementia subtype, changes in the person's brain have been happening for a long time. During this stage, it is ideal to ensure that advance care planning has occurred to protect the person's wishes. Advance directives exist that are specific to people living with dementia.
Most types of dementia including Alzheimer's, Lewy body dementias, and frontotemporal dementia are neurodegenerative diseases. Protein misfolding is a cardinal feature of these conditions. The next most common type of dementia after Alzheimer's is vascular dementia, a cerebrovascular disease. These are the main primary types. Secondary types of dementia are secondary to a pre-existing condition, such as Huntington's dementia or HIV-associated dementia. Different dementias have different causes and risk factors. But all types are characterized by loss of neurons and consequent functioning. Vascular dementia accounts for at least 20% of dementia cases, making it the second most common type. It is caused by disease or injury affecting the blood supply to the brain, typically involving a series of mini-strokes. Symptoms depend on where in the brain the strokes occurred and whether the blood vessels affected were large or small. Repeated injury can cause progressive dementia over time, while a single injury located in an area critical for cognition can lead to sudden cognitive decline. Elements of vascular dementia may be present in all other forms of dementia. Brain scans may show evidence of multiple strokes of different sizes in various locations.
Diagnosis is usually based on history of the illness and cognitive testing with imaging. Imaging can help to determine the dementia subtype, and to exclude other causes. Blood tests are usually taken to rule out other possible reversible causes such as hypothyroidism. The mini-mental state examination is an often used test to screen cognitive ability. MMSE scores are set at 24 to 30 for a normal cognitive rating and lower scores reflect severity of symptoms. RUDAS, the Rowland Universal Dementia Assessment Scale, is a short dementia screening test for use in diverse multi-ethnic communities designed to overcome language and cultural differences. Other cognitive tests include the abbreviated mental test score, the modified mini-mental state examination, the Cognitive Abilities Screening Instrument, the Trail-making test, and the clock drawing test. The MoCA is a reliable screening test and is available online for free in 35 different languages. The MoCA has also been shown somewhat better at detecting mild cognitive impairment than the MMSE. People with hearing loss, which commonly occurs alongside dementia, score worse in the MoCA test, which could lead to false diagnosis. An integrated cognitive assessment called CognICA is a five-minute test that is highly sensitive to the early stages of dementia.
Fourteen risk factors for dementia, many of which are potentially modifiable, exist today. These include high blood pressure, high levels of LDL cholesterol, vision loss, hearing loss, smoking, obesity, depression, inactivity, diabetes, lower levels of education, low social contact, over-indulgence in alcohol, traumatic brain injury, and air pollution. Several of the group are known as vascular risk factors that may be possible to be reduced or eliminated. Managing these risk factors can reduce the risk of dementia in individuals in their late midlife or older age. A reduction in a number of these risk factors can give a positive outcome. The decreased risk achieved by adopting a healthy lifestyle is seen even in those with a high genetic risk. In addition to the above risk factors, other psychological features including certain personality traits like high neuroticism and low conscientiousness are also risk factors. For example, based on the English Longitudinal Study of Ageing research found that loneliness in older people can increase the risk of dementia by one-third. Not having a partner can double the risk of dementia. However, having two or three closer relationships might reduce the risk by three-fifths. The two most modifiable risk factors for dementia are physical inactivity and lack of cognitive stimulation.
There are several non-pharmacological and limited pharmacological options for treating dementia. Some types of medication are used to address the symptoms in different subtypes but the benefit is small. More than half of people with dementia may experience psychological or behavioral symptoms including agitation, sleep problems, aggression, and psychosis. Treatment for these symptoms is aimed at reducing the person's distress and keeping the person safe. Treatments other than medication appear to be better for agitation and aggression. Cognitive and behavioral interventions may be appropriate. Some evidence suggests that education and support for the person with dementia as well as caregivers and family members improves outcomes. Exercise programs are beneficial with respect to activities of daily living. As with all brain disorders, some people with dementia could potentially be a danger to themselves or others. Such behavioral symptoms might result in the person being involuntarily admitted to a mental health ward for assessment, care and treatment. However, this is a last resort, and potential alternatives could be considered by family or friends of people with dementia. Palliative care interventions may lead to improvements in the quality of life, management of symptoms, and comfort in dying.
The number of cases of dementia worldwide in 2021 was estimated at 57 million, with close to 10 million new cases each year. It is the seventh leading cause of death with some 1.8 million lost lives in 2021. By 2050, the number of people living with dementia around the world is estimated to be over 150 million. Globally, the fastest increase in serious health-related suffering by 2060 is expected to occur among people with dementia. Around 7% of people over the age of 65 have dementia, with slightly higher rates up to 10% of those over 65 in places with relatively high life expectancy. An estimated 58% of people with dementia are living in low and middle income countries. The prevalence of dementia differs in different world regions, ranging from 4.7% in Central Europe to 8.7% in North Africa Middle East. The incidence of dementia increases exponentially with age, doubling with every 6.3-year increase in age. Dementia affects 5% of the population older than 65 and 20-40% of those older than 85. Rates are slightly higher in women than men at ages 65 and greater.
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Common questions
What is dementia and how does it affect daily life?
Dementia is a syndrome characterized by a general decline in cognitive abilities that affects a person's ability to perform everyday activities. It typically involves problems with memory, thinking, behavior, and motor control alongside emotional problems and difficulties with language.
How many stages of dementia exist and what are they called?
The course of dementia is often described in three major stages: early, middle, and late. These stages show a pattern of progressive cognitive and functional impairment while the Global Deterioration Scale uses seven stages in the development of dementia.
Which types of dementia are most common after Alzheimer's disease?
Vascular dementia accounts for at least 20% of dementia cases making it the second most common type after Alzheimer's. Vascular dementia is caused by disease or injury affecting the blood supply to the brain typically involving a series of mini-strokes.
What risk factors can reduce the chance of developing dementia?
Fourteen risk factors for dementia exist today including high blood pressure smoking obesity depression and physical inactivity. The two most modifiable risk factors for dementia are physical inactivity and lack of cognitive stimulation.
How many people had dementia worldwide in 2021 and how many new cases occur each year?
The number of cases of dementia worldwide in 2021 was estimated at 57 million with close to 10 million new cases each year. It is the seventh leading cause of death with some 1.8 million lost lives in 2021.