– It is a deficit in memory caused by brain damage, disease, or psychological trauma.
– Can also be caused temporarily by the use of various sedatives and hypnotic drugs.
– Essentially, amnesia is loss of memory.
Organic or neurological causes
Functional or Psychogenic causes
– The hippocampus is a horse-shoe shaped area of the brain that plays an important role in consolidating information from short-term memory and forming long-term memory.
Damage to Hippocampal region results in a failure to remember and may loss ability to form
May also results to remember spatial layouts or landmarks.
What is Alzheimer’s disease?
It is an irreversible, progressive brain disease that slowly destroys memory and thinking skills, and eventually even the ability to carry out the simplest tasks.
It is a severe form of senility marked by advanced memory loss.
Was first identified and named after Dr. Alois Alzheimer.
Alzheimer’s Disease and the Brain
Alzheimer’s disease leads to nerve cell death and tissue loss throughout the brain. Over time, the brain shrinks dramatically, affecting nearly all its functions.
In the Alzheimer’s brain:
● The cortex shrivels up, damaging areas involved in thinking, planning and remembering.
● Shrinkage is especially severe in the hippocampus, an area of the cortex that plays a key role in formation of new memories.
● Ventricles (fluid-filled spaces within the brain) grow larger.
I. Causes of Alzheimer’s disease
Neurologically, AD is characterized by a loss of neuron and synapses in the cerebral cortex and certain sub-cortical regions of the brain.
Two abnormal structures called plaquesand tangles are prime suspects in damaging and killing new memories.
AMNESIA FOR ALZHEIMER’S DISEASE
Plaquesare deposits of a protein fragment called beta-amyloid that build up in the spaces between nerve cells.
Tanglesare twisted fibres of another protein called tau that build up inside cells.
II. Causes of Alzheimer’s disease
Reduced synthesis of the neurotransmitter Acetylcholine. May have caused the amnesia in
Acetylcholine used in the communication between neurons in the brain.
Ach secretion is considered below normal in the brains of Alzheimer’s patients.
Stages of Alzheimer’s disease
I. Earliest Alzheimer’s- In the earliest stages, before symptoms can be detected with current tests, plaques and tangles begin to form in brain areas involved in:
Learning and memory
Thinking and planning
II. Mild to Moderate Alzheimer’s Stages- Plaques and tangles also spread to areas involved in:
Speaking and understanding speech
Your sense of where your body is in relation to objects around you
As Alzheimer’s progresses, individuals may experience changes in personality and behavior and have trouble recognizing friends and family members.
III. Severe Alzheimer’s – Individuals lose their ability to communicate, to recognize family and loved ones and to care for themselves.
Alzheimer’s does not affect all memory capacities equally.