Dementia is an illness of old age, usually characterized by a progressive decline in cognitive functions from the previous level. Loss of memory for the recent events is a classical feature. A number of cognitive functions including new learning, intelligence, decision making, executive functioning and language are affected, besides the memory. In the later stages, the patient may not even be able to take care of self, and the illness affects the basic personal and social skills.
One of the earliest symptoms of dementia is impairment of memory for recent events. Onset is usually slow and gradual, though it is sudden in vascular dementia. There is a progressive deterioration of various intellectual abilities. Often the family members observe that the patient starts forgetting about his daily use belongings, such as purse, pen or shoes and about recent events and whom he met the day before. He forgets about conversations, events of the day, telephone numbers, etc. A distinguishing feature is that the person himself is often not aware of this development. Interestingly, memory for remote events even going back to his early life is preserved.
In later stages, he may even forget names of close relatives, their occupations and places of stay. The patient may even have difficulty recalling the names of grandchildren. The progressive memory impairment may lead to faulty orientation to time and place. Symptoms often worsen at night. Ability to learn new tasks and skills gets impaired. In later stages, judgment also gets affected.
In the early phases, the patient may feel anxious and concerned over the memory disturbance, and may also feel depressed. But as the disturbance increases, the person does not accept memory loss. Sometimes it may progress on to suspiciousness. The patient may become impulsive and socially disinhibited. He may cut coarse jokes without caring for the consequences. In later stages, the patient may be unable to take care of his personal needs, may become sleepless and restless. He may get lost in surroundings familiar to him. In later stages, person may not even be able to take care of basic personal needs and need supervised care.
Focal neurological deficits like fits, weakness of limbs or body, aphasia or dysarthria and failing vision may appear in later stages of dementia.
Behavioural and psychological symptoms like apathy, depression, irritability, agitation/aggression are also common in subjects with dementia. Some patients may also develop paranoid symptoms and disorganized behaviour in later stages of illness.
Thus dementia often starts off with just memory problems, but later involves:
- Difficulty communicating (recognizing, identifying, naming, finding words to explain)
- Difficulty planning and carrying out day-to-day tasks (using household appliances like microwave or washing machine, leaving the gas stove on after cooking, etc)
- Ability to learn, reason, retain or recall past experience
- Changes in mood, personality and judgement
Dementia is differentiated from delirium, which is an acute illness characterized by altered sensorium or decreased level of consciousness, disorientation for time and place, fluctuating course with worsening in evening. Perceptual disturbances like illusions and hallucinations are characteristic features of delirium. Delirium is a medical emergency and is usually short lasting unlike dementia.
Dementia is a result of degenerative changes in the brain. The most common causes of dementia are Alzheimer’s disease, vascular dementia, fronto-temporal dementia, and dementia with Lewy bodies. One study from India analyzing types of dementia found Alzheimer’s disease in 38.3%, vascular dementia in 25.4%, fronto-temporal dementia in 18.7%, diffuse Lewy body disease in 8.9%, and mixed dementia in 8.6% of the patients. In dementia, the brain cells tend to degenerate and die more rapidly than the normal ageing process.
Some of the important characteristics of these different types of dementia are discussed as below:
Alzheimer’s disease: Alzheimer’s disease is the most common cause of dementia, contributing to about 40% cases of dementia in India. Loss of memory for recent events is initial manifestation, worsening slowly over time and involving other cognitive functions. Though there is difficulty in remembering the events that have happened recently, the patient is able to recall the events of remote past. The patient has also difficulty in recalling particular words and naming objects.
Family members would give history of the patient having:
- Difficulty in learning new things.
- Difficulty remembering appointments or phone messages.
- Inability to remember the names of people or places and difficulty communicating with others.
- Forgetting where they have put things of daily use like watch, purse, etc. The patient may also worry that someone has taken away.
- Denial of the memory problem, The person may attempt to cover up the deficit.
Cause lies in degenerative changes in the brain. The damaged tissue in brain builds up to form deposits called ‘plaques’ and ‘tangles’. These cause brain cells around them to die.
Vascular dementia: Vascular dementia, also called multi infarct dementia, is the second commonest cause of dementia. Compared to the West, it is more common in India. It is usually caused by blockage in the blood vessels supplying the brain, leading to ischemia or infarct. MRI of brain would reveal multiple infarcts. Sometime vascular dementia develops after an attack of stroke. Memory disturbances come in form of step ladder pattern, increasing with a fresh infarct. Risk factors include high blood pressure, smoking, diabetes or high cholesterol.
Some of the important characteristics of vascular dementia are:
- Memory loss and difficulty concentrating.
- Language problems like aphasia
- Mood swings, depression
- Episodes of confusion, aggressive behaviour, hallucinations
- Physical deficits like paralysis or weakness of limbs
Both vascular dementia and Alzheimer’s disease can also co-exist.
Lewy body dementia: Lewy body dementia is a relatively less common type of dementia, compared to the Alzheimer’s disease and vascular dementia. It is characterized by development of protein deposits (Lewy bodies) building up in the brain. Some of the symptoms overlap with Alzheimer’s disease and Parkinson’s disease.
Characteristic features of Lewy body dementia are
- Fluctuating level of attention and alertness
- Vivid visual hallucinations (seeing human or animal figures)
- Trembling of hands, muscle stiffness, falls or difficulty with walking.
Fronto-temporal dementia: In fronto- temporal dementia, the front part of the brain consisting of frontal and temporal lobes is predominantly involved. It is slightly more common than Lewy body dementia. It is seen in relatively younger people compared to Alzheimer’s disease and vascular dementia, usually starting in 50s and 60s. Personality deterioration, social disinhibition, and behavioural disorganization are common. A person, who was usually very polite and proper, might become irritable or rude. Memory may remain reasonably intact for a long time.
Any patient developing memory disturbance or personality deterioration in the age group above 50, occurring over a period of few months needs to consult the physician, psychiatrist or neurologist. The person needs to be examined in detail to rule out dementia. Mini Mental Sate Examination (MMSE) or its Hindi adaptation called Hindi Mental Status Examination (HMSE) are commonly used to screen for dementia. Both can be administered in a clinic setting and take about 10 minutes.
Detailed physical and neurological examination is conducted. The person needs to be investigated for basic haematology, liver function, kidney function, thyroid, nutritional deficiencies especially vitamin B12 and folate. Sometimes, nutritional deficiencies or hypothyroidism may be responsible for the dementing changes. Once corrected, the memory disturbance improves. Similarly chronic alcohol use can also lead to dementia.
A CT scan or magnetic resonance imaging (MRI scan) are also performed to detect the degenerative changes. Diagnosis of dementia is, however, mainly clinical.
Dementia, being a degenerative illness, is mostly untreatable. Investigations are generally performed to find out a treatable cause, which if identified (e.g., hypothyroidism, vitamin deficiency ), can be corrected. Certain measures like good nutrition, regular exercise and adequate sleep can improve the quality of life of the patient, and also help in slowing the progression of disease. Simplifying activities or modifying expectations to the cognitive and skill level of the patient can eliminate frustration. The home environment may need to be modified (lighting, positioning of bed, toilets, etc) to compensate for the patient’s deficits.
The family members caring for the patient with dementia also face tremendous stress and burden in the care giving role and also need psychological support, guidance and help. They need to be educated about the problem and guided how to deal with it.
Certain medications like donepezil, rivastigmine and galantamine (also called cholinesterase inhibitors) are useful in early stages of the Alzheimer’s disease, and slow down the progress of dementia. These increase the acetylcholine levels in the brain. Memantine is another drug which improves symptoms.
In vascular dementia, blood pressure needs to be kept under control and anticoagulant therapy is used to reduce the risk of further infarction.
A number of risk factors like advancing age, illiteracy, alcohol, hypertension, diabetes, poor socioeconomic status, trauma, familial or genetic factors, nutritional factors, and stroke have been identified. Some of these are preventable and hence can reduce the incidence of dementia.
The following strategies are helpful in preventing development of dementia and also in slowing its progress, once developed:
- Proper lifestyle
- Proper diet
- Mental activity like reading, solving puzzles, Sudoku, etc.
- Regular physical exercises