Alzheimer’s Disease: Causes, Stages, Treatment, Prognosis
With the increase in life expectancy of people, various geriatric problems are coming into spotlight. Alzheimer's disease, a type of dementia is one of them. In spite of the fact that patients present with the complaint of 'not remembering', the nature of the problem differs. While some individuals forget names of people (Anomia) some others forget new events. Because of the increasing number of people who are coming in with complaints of this 'forgetfulness' a lot of research is being conducted in the field of dementia.
What is Dementia?
Dementia can be defined as a progressive degeneration of the brain which leads to deterioration in memory and other cognitive functions. Generally, dementia affects a person at an advanced age. It must be differentiated from cognitive decline due to old age.
Some of the common types of dementia are as follows:
- Alzheimer's disease (about 50% to 70% of patients)
- Vascular dementia (25% of the cases)
- Lewy body dementia (15%)
- Frontotemporal dementia
- Parkinson's dementia,
- Creutzfeldt–Jakob disease etc.
Dementia of any form is irreversible. No known definite cure has been found. Certain drugs are used for symptom alleviation (like anti-depressants, anxiolytics, anti-psychotics etc.)
Alzheimer's Disease (AD)
The history of Alzheimer's Disease dates back to 1906 when German physician Dr. Alois Alzheimer's patient died after suffering from severe memory problems, acute confusion, difficulty in understanding what is being asked etc. Autopsy of the brain revealed dense deposits of neuritic plaques surrounding the nerve cells. Twisted bands of neurofibrillary tangles inside the nerve cells were found. This disorder which is referred to by his name has almost become synonymous with dementia to the lay person.
Alzheimer's Disease in Women
Epidemiological studies have shown that women tend to suffer more from Alzheimer's disease than men. This cannot simply be attributed to the greater life expectancy of women which makes women live longer and thus there must be some other explanation. It has been found that mitochondria in younger females are protected against amyloid-beta toxicity and they tend to generate oxygen that is less reactive. Oxidation is reduced. Apoptosis among them is less. However, these advantages are lost in mitochondria of older females probably because of lower estrogens levels.
Stages of Alzheimer's Disease Progression
Alzheimer's Disease generally progresses through stages. They are described below:
Pre-clinical/Pre-symptomatic Stage of Alzheimer's Disease:
'Biomarker' tests can reveal beta-amyloid and tau proteins in blood and cerebrospinal fluid of a high-risk patient long before any form of cognitive decline sets in. Specialized Positron Emission Tests and Magnetic Resonance Imaging scans can also show subtle changes in the brain.
Pre-dementia/ Mild Cognitive Impairment Stage of Alzheimer's Disease
The earliest symptoms of Alzheimer can be mistaken for effects of ageing or stress. Neuropsychological testing can reveal mild cognitive deficits. The most noticeable deficit is in recalling new information. Apathy, which can be mistaken for depression, can be noticed even in this early stage, and remains the most constant neuropsychiatric symptom throughout the disease. The diagnosis at this stage can be mild cognitive impairment (MCI)
Mild Stage of Alzheimer's Disease
Loss of energy and spontaneity, minor memory loss, mood swings, difficulty in learning, increased reaction time etc. can be present in this stage. They start to prefer the familiar to anything new. Even though they can perform day-to-day tasks independently, they may need help with more complicated tasks. Speech becomes logopenic (slow speech, with impaired syntactic comprehension, and naming). Loss of sense of direction can set in. Patients might forget events. As they become aware of this forgetfulness, they may become depressed, anxious, and irritable.
Moderate Stage of Alzheimer's Disease
Disability increases as patients forget according to the Ribot's Law (newly learned information is lost earlier than older memories). Orientation of time and place is lost. A person can get lost even in familiar surroundings. Confabulation sets in to fill in blanks in memory. New words may be invented and alternate words are used to compensate for words which are difficult to find. Memory for faces might begin to be lost.
Severe Stage of Alzheimer's Disease
The patient becomes more unresponsive. Bowel and bladder control might be lost. Faces cannot be recognised. Chewing and swallow pose problems which pave the way for pneumonia, infections, and other illnesses. Eventually it leads to coma and death.
Causes of Alzheimer's Disease
- Genetic – Family and twin studies have lent support to heritability of Alzheimer's disease
- Cholinergic – This hypothesis states that reduced synthesis of acetylcholine leads to Alzheimer's disease
- Amyloid beta protein deposits form plaques in the brains of Alzheimer's disease patients
- Tau protein leads to the formation of neurofibrilary tangles that cause neural degeneration
Diagnosis of Alzheimer's Disease
Only a probable diagnosis can be arrived upon by studying the history and symptomatology of the illness.
The National Institute of Neurological and Communicative Disorders and Stroke (NINCDS) and the Alzheimer's Disease and Related Disorders Association (ADRDA, now known as the Alzheimer's Association) established the NINCDS-ADRDA Alzheimer's Criteria for diagnosis in 1984. This was later updated in 2007. The criteria specify that Alzheimer's disease must be confirmed by neuropsychological testing to arrive at a probable diagnosis.
Nuclear medical imaging and blood tests can help with the diagnosis by ruling out other forms of dementia. Moreover, only the examination of brain tissue can confirm diagnosis.
Neuropsychological Examination for Alzheimer Patients
A detailed neuropsychological examination can reveal the following:
- Word finding difficulty
- Neologisms (or finding new words)
- Echolalia (repeating words being heard)
- Poor sense of direction
- Fluent but incoherent expressive speech
- Difficulty in understanding commands
- Anomia (not able to name objects)
- Agnosia (not able to recognise objects)
- Apraxia (impaired knowledge of how to perform certain tasks)
- Short term memory impairment
- Poor performance in construction tests
- Poor handwriting.
Treatment and Management of Alzheimer's Disease
Although there is no cure for Alzheimer's disease, a symptomatic management is what is done. The treatments available aim at slowing down the progression of the disease.
- Medication For Treating Alzheimer's Disease- Cholinesterase inhibitors are used a lot in the treatment of Alzheimer's disease. Symptomatic management of problems like anxiety, depression, restlessness, aggression, psychosis can be done using medicines.
- Memory Aids To Help Patients With Alzheimer's Disease - Aids to help recognition and recall can be very helpful for Alzheimer's disease patients. A picture book can help in reminding familiar faces. Arrows and fluorescent markers can help them find their way around the house. GPS can help them locate their house when they get lost. Alarms can ensure that they perform tasks at the regular times.
- Cognitive Training- Because of recent findings about brain plasticity, training programmes have been developed for Alzheimer's disease patients to help them improve and practice the lost cognitive functions. Regular brain exercise has been found to slow down disease progression.
- Behavioural Intervention- This can help to treat incontinence and other behavioural abnormality like anger outbursts etc.
- Psychosocial support- It is a very important aspect in case of Alzheimer's disease. Alzheimer's disease patients often suffer from mental health problems like depression and anxiety. Many times, they are ignored. Counselling and support can help reduce caregiver burden.
Prognosis of Alzheimer's Disease
Prognosis or the course of the disease is very poor for Alzheimer's disease. As Alzheimer's disease is a progressive neurodegenerative disease, the ultimate fate of the patient is coma or death. However, active interventions can help to slow down the process.
Not much is known about the exact reason as to why Alzheimer's disease is more frequent in women, researchers indicate menopause to be a cause. A recent study has found that two-third of the American population suffering from Alzheimer's disease are women. According to the Alzheimer's Association (2014), women in their 60s are twice as likely to develop Alzheimer's disease as to develop breast cancer. Nevertheless, there are more awareness campaigns for breast cancer than for AD. Thus an increased awareness is needed which will help in earlier detection, greater care, and slower progress of the disease. However, much in-depth studies are required in field.