Alzheimer’s Disease is an irreversible, degenerative illness of the brain. How symptoms of the disease affect a particular individual and how rapidly the illness progresses, varies from person to person.
In the earliest stage of the illness, the person experiences short-term memory loss, confusion about places, loss of initiative and mood or personality changes. A person in the early stage of Alzheimer’s may take longer to complete routine chores, may display poor judgement in decision-making, may have difficulty handling money or paying bills and may avoid social contact.
As the disease progresses the person may experience the following symptoms:
At this stage, the person requires supervision.
Eventually, the person may lose the ability to communicate verbally, to recognize family members or their own image in the mirror, or to control bowels or bladder. The person may lose weight, have seizures, have difficulty swallowing, skin infections, and may demonstrate the impulse to touch everything or put things in their mouths. The person is unable to care for him or herself.
Vascular dementia occurs when blood vessels in the brain either burst or are blocked by blood clots. The onset of vascular dementia can be sudden if caused by a stroke, or gradual if caused by a series of very small strokes. Sometimes there are no obvious physical effects but often there may be typical signs of a stroke, i.e. partial or total paralysis of a limb or speech problems. Dementia occurs when areas of the brain linked to intellectual functions are damaged or destroyed. Vascular dementia progresses in a stepwise fashion: mental function deteriorates quite suddenly, then stabilizes, or even improves for a time, until the next stroke occurs. Episodes of acute confusion after each stroke are quite common.
People in the early stages of vascular dementia typically have greater awareness of their disability accompanied by a greater preservation of their personality than those with Alzheimer’s. Other features of vascular dementia are speech problems, unstable expression of emotions, depression and epileptic seizures. Hallucinations or delusions may also be experienced.
Once established, vascular dementia cannot be reversed by drug treatment but rehabilitation is possible in some cases. Persons with vascular dementia should consult a specialist doctor who may be able to decrease the risk of further strokes.
Lewy Body Disease is another form of dementia. The main features of the disease are dementia and tremor, rigidity, slow movement and abnormal gait. The dementia is often mild at the onset of the condition, with impairments of memory, visual-spatial skill, language, calculation and decision-making. Compared to Alzheimer’s Disease, people with Lewy Body disease seem to have more problems with visual-spatial activities such as drawing or copying. The degree of dementia can vary greatly, both within a day and from day to day. People in the early stages of Lewy Body Disease seem to have reasonably good short-term memory but have difficulties with attention and concentration. Many people with the disease exhibit acute confusion. Another characteristic is the presence of visual hallucinations and delusions. Hallucinations often occur when the person wakes up. Currently, there is no treatment for Lewy Body disease.
Frontotemporal dementia is the name given to any dementia caused by damage to the frontal lobe of the brain. It includes Pick’s Disease but can also be caused by other diseases. Frontotemporal dementia frequently has a slow onset. Early symptoms include a change in personality and loss of judgment, often leading to inappropriate or uninhibited behaviour. Speech is also affected in the early stages. Many individuals with Frontotemporal dementia have difficulty remembering the meaning of words. Motor skills can also be impaired.
This dementia differs from Alzheimer’s in that it has a greater impact on personality and behaviour; memory and time and place orientation to a lesser degree. The affected person may withdraw socially and begin to neglect personal appearance. People in the early stages of Frontotemporal dementia appear to be constantly irritable. Many people with Frontotemporal dementia are not aware that anything is wrong and may become very aggressive if challenged about their behaviour. Depression is common in people who have Frontotemporal dementia. The person may become obsessive, repeating patterns of movement and behaviour. Currently, there is no specific treatment for Frontotemporal dementia.
Some people who have Parkinson’s Disease develop dementia. Parkinson’s is caused by a loss of nerve cells and dopamine (a neurotransmitter) in the motor control centre of the brain. The characteristic symptoms, which arise gradually, are tremor, stiffness of limbs and posture, and slowness of movement, speech and thought. While there are treatments that address the physical symptoms of Parkinson’s Disease, these do not improve the dementia symptoms.
Excessive alcohol consumption over many years can lead to problems affecting memory and learning, although whether this is true dementia is a subject of debate. Some improvement in functioning can occur if the person stops drinking altogether.
Huntington’s Disease (also known as Huntington’s Chorea) is an inherited degenerative brain disease. The effects include twitching and jerking of limbs and facial muscles, personality changes and depression. Dementia occurs in the majority of cases. The discovery of a genetic marker has enabled scientists to predict, with a fairly high degree of certainty, who will develop the disease.
Down’s syndrome is characterized by intellectual disability. People with Down’s syndrome have an increased risk of developing dementia.
Creutzfeldt-Jacob Disease is a very rare illness, occurring in about one person in a million. It is caused by a slow virus. Symptoms do not appear for some years after infection and there is no evidence that the disease can be transmitted from person to person through normal social or sexual contact. Creutzfeldt-Jacob Disease has been diagnosed most frequently in people who have received substances extracted from the human brain (e.g. human growth hormone). While the onset of the disease is slow, the course of the disease is very rapid, lasting from one month to two years. The disease is characterized by behavioural disturbances and sudden spasmodic jerking movements.