According to statistics, dementia affects about 36 million people globally and about 10% of people develop the disease at some point in their lives. It becomes more common with age. As more people are living longer, dementia is becoming more common in the population as a whole. Also known as Senility, dementia is a broad category of brain diseases that causes gradual decrease in the ability to think and remember. It is a collective term that is used to describe various underlying brain disorders or damage that can lead to memory loss, language and thinking.
While the likelihood of dementia increases with age, it is not to be misunderstood with normal part of aging. Light cognitive impairments and poorer short-term memory can happen as normal part of aging and this is known as age related cognitive decline and not dementia.
Alzheimer's disease is the best known and most common form of dementia, although there are others types including Vascular Dementia, Lewy Body Dementia and Frontotemporal dementia.
The loss or damage of nerve cells or neurons in the brain can cause dementia. Alzheimer's disease is the leading cause. Dementia can also be caused by head injury, a stroke or brain tumor. Brain cell death caused by conditions such as cerebrovascular disease like stroke can cause vascular dementia. This prevents adequate blood flow, depriving brain cells of oxygen.
Post traumatic dementia is directly related to brain cell death caused by injury. Some repetitive injuries suffered by sports players are linked to certain form of dementias appearing later in life. Dementia can also be caused by diseases such as Prion disease, from certain types of proteins, HIV infection, medication interactions, depression and vitamin deficiencies. A small proportion of dementia cases run in families.
Signs and symptoms
Other than the decrease in the ability to think and remember even daily functions, some common symptoms of dementia are:
The first thing is to assess memory performance and cognitive health. A healthcare professional would ask a set of questions to test knowledge of facts that should be known to any adult to get an indication whether there is dementia or not. The patient is asked to complete the standard tests, and answers are recorded to form a diagnostic indication. Tests to assess a person's mental ability are conducted and test scores are ascertained. Questions such as 'What is your age', 'What is the time', 'What is the year', Counting 20 backward etc are asked. One task for the patient is to write the hours of a clock face around a blank circle on a piece of paper and with accurate relative spacing. These cognitive tests measure dementia symptoms and other tests help to narrow down, if for example, it is Alzheimer's disease.
As brain cell death cannot be reversed, there is no known treatment to cure a degenerative cause of dementia symptoms or fully halt its progress. The aim is to provide care and treat symptoms rather than their underlying cause and manage the disorder. If dementia symptoms are due to reversible, non-degenerative cause, treatment is possible to prevent or halt further brain tissue damage.
Symptoms of Alzheimer's can be reduced by drugs to improve the person's quality of life. Educating and providing emotional support is imperative. Exercise programs are beneficial. Treatment of behavioral problems of psychosis with antipsychotics is not usually recommended due to increased risk of death.
Other than age which is the biggest predictor of dementia, certain risk factors are modifiable. These risk factors include:
Motoric cognitive risk syndrome
Motoric Cognitive Risk Syndrome or MCR is a clinical approach to identify older adults who are at risk of converting to dementia. However, being diagnosed with MCR does not automatically mean that a person has dementia but is on the pathway.
Motoric cognitive risk (MCR) syndrome is a fairly new 'pre-dementia assessment'. It is characterized by the presence of cognitive complaints such as slow gait and cognitive complaints which are simple and easy to identify and assess in older adults.
In all, there are four subtypes of MCR defined by substituting slow gait with short stride length (MCRs1), slow swing time (MCRsW), high stride length variability (MCRslv) and high swing time variability (MCRswv). MCR subtypes are not mutually exclusive.
A simple test that measures how fast people walk and whether they have any cognitive issues can determine how likely they are to develop dementia, which can cause Alzheimer's within 12 years according to scientists at the Albert Einstein College of Medicine of Yeshiva University and Montefiore Medical Center.
Criteria for MCR
The prevalence of MCR is higher with older age, but there are no gender differences. Motoric cognitive risk in older adults is an early predictor of cognitive decline ultimately leading to Alzheimer's. As the elderly population continues to increase, the number of dementia patients are also likely to increase. MCR is a new symptom that identifies the probability of acquiring dementia. Studies reveal that those who develop MCR were approximately twice more likely to develop dementia. Those who have this disorder also appear to be at greater risk of developing cognitive impairment that leads to Alzheimer's disease among other forms of dementia. Typical symptoms include slow gait, memory lapses and instances of getting lost.
Diagnosis of MCR
Motoric cognitive risk syndrome is diagnosed by simple questions related to memory. Measuring gait speed over a fixed distance is another way of diagnosis. Independent of cognitive tests, MCR has been assessed by various study methods.
Gait speed is measured by the fixed distance that a person walks within a fixed given period of time. The average or mean gait speed is 81.8 cm/s which is slightly less than three feet traveled per second. Those with lesser walking speed than the standard deviation time are viewed as slow walkers. Those diagnosed with MCR perform very badly on most cognitive tests. Those with MCR also exhibit a higher prevalence of vascular disease. Many forms of dementia demonstrate motor issue as the disease progresses due to further damage of brain tissue.
MCR and determining risk of dementia
Diagnosing MCR is simple and can easily be implemented in a clinical setting without advanced neuro-imaging or spinal fluid examinations. Test for MCR can be done by a trained healthcare worker, not necessarily by a doctor. This way an adult at risk for dementia can be identified even without an MRI machine or the latest amyloid PET (Positron Emission Tomography) scan.
Risk factors of MCR are defined and selected risk factors are checked for in older people considering medical illnesses, lifestyle choices, activity level, weight and level of education all of which have been linked to risk of dementia. Stroke, Parkinson's disease, depression, limited activity and obesity turn out to be significant predictors of MCR. If someone meets the criteria, there is a need to investigate the causes and suggest preventive strategies. The MCR approach has been tested successfully in several countries and has been found to be a strong predictor for dementia.
Importance of MCR
MCR is important because it predicts dementia so that the goal would be to act on these risk factors. Early detection of risk factors can help reduce people's risk of stroke by getting them to exercise or putting them on aspirin. Being sedentary is a risk factor of MCR and it is therefore recommended to increase exercise levels in older people, and thus potentially reduce the risk of MCR and ultimately of dementia.
As there are no medications to prevent risk of dementia or cure it, the main intervention would be healthy lifestyle measures, increased physical activity, engaging in cognitively stimulating activities and partaking a healthy diet. Controlling medical risk factors especially vascular disease, lowering blood pressure and cholesterol, reducing weight - all these would have an impact on reducing the risk of dementia. However, it is essential to remember that identifying MCR is not the same as diagnosing that an older person has dementia. MCR is a red flag - an opportunity for clinicians and researchers to reduce the number of people who convert to dementia.
Alzheimer's disease is a progressive mental disorder that brings about changes in the brain slowly leading to dementia. Named after the German physician Alois Alzheimer, Alzheimer's disease has 2 characteristic neuronal changes : Loss of cholinergic cells in the basal forebrain and the development of neuritic plaques in the cerebral cortex. Neurofibrillary tangles can also occur due to Neuritic plaques.
Here the brain cells degenerate and die thus causing a decline in the mental functioning and memory of a person. Alzheimer's disease (AD) or Presenile dementia as it was earlier known as, is one of the primary causes of dementia. The levels of the brain neurotransmitters serotonin, norepinephrine and acetylcholine are found to be low in AD. This kind of brain disorder causes loss of social and intellectual skills of a person. In severe cases it interferes with the day-to-day activities of a person.
Alzheimer's disease causes
There are 4 major cognitive deficits arising out of AD :
1. Amnesia : Memory loss is probably the most common symptoms of Alzheimer' disease.
2. Aphasia : Loss of Language - Failure to recollect names of objects
3. Apraxia : Inability to perform voluntary movements
4. Agnosia : Inability to recognize people and places
Alzheimer's disease diagnosis
1. A physical examination and a neurological examination to check:
2. Brain imaging (CT scans, MRI) to check for tumors, etc.
3. Lab tests for thyroid etc so as to rule out other possibilities for memory loss
Treating Alzheimer's disease
As this disease is of degenerative nature, there is no permanent cure. Early diagnosis and changes in lifestyle can slow down its progression or improve the quality of life for the afflicted.
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Bibliography / Reference
Collection of Pages - Last revised Date: May 31, 2023