Amnesia (Forgetfulness)
Amnesia is the total or partial loss of memory. Anterograde amnesia is the loss of memory for events preceding the amnesic event e.g. head injury, hanging, gas poisoning, after electro convulsive therapy.
Amnesia is a general term that describes memory loss. The loss can be temporary or permanent, but 'amnesia' usually refers to the temporary variety.
Paramnesia is characterised by falsification or distortion of memory. Confabulations are stories that are made up to fill in gaps with fabrications e.g. senile psychosis.
Infantile amnesia, or the inability to remember anything at all from the first few months or years of life, is universal. It is thought that the memory processes of the brain take time to develop. Anterograde amnesia is a form of amnesia, or memory loss, where new events are not transferred to long-term memory. After the onset of the disorder, the sufferer will not be able to remember anything that occurs after his attention is shifted away from one subject for more than a few seconds.
Symptoms of Amnesia
The symptoms of amnesia depend on the cause, but generally include:
- Memory loss
- Confusion
- Inability to recognise familiar faces or places
- Once the person recovers, they typically have no memory of their amnesia episode.
Causes of Amnesia
1. Amnesia of sudden onset, usually with gradual but incomplete recovery.
a. Cerebral infarction.
b. Cerebral embolism.
c. Head injury.
d. Hemorrhage within the meninges of the brain.
e. Carbon monoxide, cooking gas poisoning
2. Amnesia of sudden onset and brief duration with full recovery:
a. Epilepsy
b. Cerebral concussion.
3. Amnesia of slow onset with varying degrees of recovery, usually leaving a permanent
residue.
a. Chronic alcoholism.
b. Inflammation of the brain.
c. Tuberculosis of the brain.
4. Slow progressive amnesia.
a. Brain tumors
b. Old age.
c. Alzheimer's disease.
Memory loss can be caused by a wide range of conditions, including:
- Head injury
- Severe illness
- High fever
- Seizures
- Emotional shock or hysteria
- Alcohol-related brain damage
- Certain drugs, such as barbiturates or heroin
- General anaesthetics
- Electroconvulsive therapy
- Stroke
- Transient ischaemic attack (a 'mini stroke')
- Alzheimer's disease
- Brain surgery.
Different types of memory
It seems that the brain has a number of different memory forms, including:
- Short term - new information is stored for a brief time. If the information isn't further processed, it will soon be forgotten.
- Long term - information from the short term memory is shifted to the long term memory.
- Declarative - conscious memories of information and events.
- Non-declarative - once learned, habits such as driving a car are ingrained and automatic.
Diagnosis methods of Amnesia
Diagnosing the cause of amnesia involves a range of tests, including:
- Medical history
- General examination
- Tests for short and long term memory recall
- Other tests related to thought processing
- Head x-ray
- Blood tests
- Computerised tomography (CT) scan
- Cerebral angiography (scans taken after a special dye is injected).
Management of Amnesia
1. Take things slow paced.
2. Try leaving visual clues within the house.
3. Use an index card, make a list of jobs to be done for the day.
4. Use a road map to find your way around.
5. Orient yourself properly before you set off on an errand.
6. Eat a good diet, low fat, vitamin E (see Diet and Nutrition)
7. Do regular exercises.
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