Types of Dementia

There are a large number of conditions which cause the symptoms of dementia, as a result of changes that happen on the brain and the ultimate loss of nerve cells (neurons). The most common causes are:

• Alzheimer's disease
• Vascular dementia
• Dementia with Lewy bodies
• Fronto-temporal dementia (including Pick's disease)

The boundaries between the different types are not necessarily distinct. Alzheimer's disease and vascular dementia are responsible for up to 90% of cases of dementia.

Alzheimer’s disease

Alzheimer's disease is the most common cause of dementia and accounts for 50% - 60% of all cases. It destroys brain cells and nerves disrupting the transmitters which carry messages in the brain, particularly those responsible for storing memories. Alzheimer's disease was first described by Alois Alzheimer in 1906.

During the course of Alzheimer's disease, nerve cells die in particular regions of the brain. The brain shrinks as gaps develop in the temporal lobe and hippocampus, which are responsible for storing and retrieving new information. This in turn affects people's ability to remember, speak, think and make decisions. The production of certain chemicals in the brain, such as acetylcholine is also affected. It is not known what causes nerve cells to die but there are characteristic appearances of the brain after death. In particular, 'tangles' and 'plaques' made from protein fragments are observed under the microscope in damaged areas of brain. This confirms the diagnosis of Alzheimer's disease.

Symptoms

Typically, Alzheimer's disease begins with lapses of memory, difficulty in finding the right words for everyday objects or mood swings. As Alzheimer's progresses, the person may:

• Routinely forget recent events, names and faces and have difficulty in understanding what is being said
• Become confused when handling money or driving a car
• Undergo personality changes, appearing to no longer care about those around them
• Experience mood swings and burst into tears for no apparent reason, or become convinced that someone is trying to harm them

In advanced cases people may also:

• Adopt unsettling behaviour like getting up in the middle of the night or wander off and become lost
• Lose their inhibitions and sense of suitable behaviour, undress in public or make inappropriate sexual advances.

Early symptoms

Every person is unique and dementia affects people differently - no two people will have symptoms that develop in exactly the same way. An individual's personality, general health and social situation are all important factors in determining the impact of dementia on him or her.
The most common early symptoms of dementia are:

Memory Loss

Declining memory, especially short-term memory, is the most common early symptom of dementia. People with ordinary forgetfulness can still remember other facts associated with the thing they have forgotten. For example, they may briefly forget their next-door neighbour's name but they still know the person they are talking to is their next-door neighbour. A person with dementia will not only forget their neighbour's name but also the context.

Difficulty performing familiar tasks

People with dementia often find it hard to complete everyday tasks that are so familiar we usually do not think about how to do them. A person with dementia may not know in what order to put clothes on or the steps for preparing a meal.

Problems with language

Occasionally everyone has trouble finding the right word but a person with dementia often forgets simple words or substitutes unusual words, making speech or writing hard to understand.

Disorientation to time and place

We sometimes forget the day of the week or where we are going but people with dementia can become lost in familiar places such as the road they live in, forget where they are or how they got there, and not know how to get back home. A person with dementia may also confuse night and day.

Poor or decreased judgment

People with dementia may dress inappropriately, wearing several layers of clothes on a warm day or very few on a cold day.

Problems with keeping track of things

A person with dementia may find it difficult to follow a conversation or keep up with paying their bills.

Misplacing things

Anyone can temporarily misplace his or her wallet or keys. A person with dementia may put things in unusual places such as an iron in the fridge or a wristwatch in the sugar bowl.
Changes in mood or behavior
Everyone can become sad or moody from time to time. A person with dementia may become unusually emotional and experience rapid mood swings for no apparent reason. Alternatively a person with dementia may show less emotion than was usual previously.

Changes in personality

A person with dementia may seem different from his or her usual self in ways that are difficult to pinpoint. A person may become suspicious, irritable, depressed, apathetic or anxious and agitated especially in situations where memory problems are causing difficulties.

Loss of initiative

At times everyone can become tired of housework, business activities, or social obligations. However a person with dementia may become very passive, sitting in front of the television for hours, sleeping more than usual, or appear to lose interest in hobbies.
If you are experiencing any of these symptoms or are concerned about a friend or relative, visit your doctor and discuss your concerns.

Diagnosis

A reasonably accurate diagnosis of dementia can be made by taking a careful history of the person's problem from a close relative or friend, together with an examination of the person's physical and mental status. There is, however, no simple test to make a diagnosis and dementia can only be confirmed with certainty by examining the brain at post mortem. When making a diagnosis, it is important to exclude other treatable conditions that cause memory loss such as depression, urinary infection, vitamin deficiency and brain tumour. An early diagnosis is helpful, because it:

• enables caregivers to be better equipped to cope with the disease progression
• provides people with dementa with an opportunity to make decisions about their financial and legal affairs before they lose the ability to do so
• gives people with dementia a better chance to benefit from existing treatments.

Early identification is important for bringing management in daily life, which would help both the person and the carer for a secured and dignified living. Further, early diagnosis would also increase timely medical and / or surgical intervention as some less common causes like chronic infections, brain tumors, hypothyroidism, subdural hemorrhage, normal pressure hydrocephalus, metabolic conditions and toxins or deficiencies or vitamin B12 and folic acid are may be treated partially.