Memory decline Flashcards
Age-related memory decline - general
§ Memory decline not inevitable, but generally accepted that there is a naturally occurring decline in some aspects of memory (memory can be improved or even reversed).
§ There is a decline in recall as people get older; recognition does not deteriorate with age.
§ Individuals who constantly use their memory and engage in mentally challenging activities experience less memory decline.
Effect of memory decline on LTM
§ Episodic memory is the worst affected by ageing.
- prospective memory particularly affected
§ Retrieval of declarative memories and information processing takes longer.
§ Performance on semantic memory tasks is equal to that of younger people, however, the speed of encoding and retrieval of semantic memory can decline.
§ No significant decline in procedural memory (able to learn, use and demonstrate forms of implicit memory).
§ Learning new memories can still occur, however the process may take longer.
Effect of memory declin on STM
§ Carrying out simple short-term memory tasks is generally not affected (remembering list of numbers).
§ Verbal recency memory (memory for recently learnt verbal info) is most affected by ageing.
§ Visual recency memory (memory for recent visual info) is less likely to be affected by age.
Effect of memory decline on WM
§ Elderly people more likely to perform more poorly than younger people on complex working memory tasks (e.g. saying a string of digits backwards, dividing one’s attention while ignoring distractions).
§ Aged 60+: the prefrontal cortex—responsible for working memory—is less active and efficient.
Reasons to explain memory decline
§ Lack of motivation; losing interest in trying to learn causes a higher chance of suffering from memory decline.
§ Loss of confidence in memory leads to less effort in learning and remembering new material.
§ Poor retrieval methods used.
§ The CNS slows down with age, lowering efficiency and effectiveness.
§ Size of the frontal lobe reduces with age and prefrontal cortex becomes less active.
Amnesia define
Amnesia: refers to memory loss, usually as a result of damage to the brain (injury, disease, stroke, seizures, drugs, alcohol, etc.) (known as organic amnesia is cause has physiological basis).
Retrograde amnesia
§ Retrograde amnesia: difficulty in recalling material learnt before the brain damage.
§ Causes include: strokes, brain tumours, surgery and electroconvulsive therapy.
§ Older memories are generally less affected.
§ Recovery of memory is possible especially if the amnesia was caused by head injury (e.g. trauma or stroke); recovery may be initially rapid then slowed.
§ Unlikely for memories to be recovered if amnesia was caused by Alzheimer’s disease.
§ Damage to hippocampus, parietal lobe or basal ganglia can lead to retrograde amnesia.
Anterograde amnesia
§ Anterograde amnesia: difficulty forming new memories after the brain damage.
§ New information cannot be learnt but memories prior to the trauma can typically be retrieved.
§ Commonly associated with Alzheimer’s disease.
§ Related to damage to the temporal lobe and hippocampus as these structures are responsible in the process of consolidation, particularly encoding and storage of long-term explicit memories.
§ Damage to CA1 (part of the hippocampus) is likely to cause Anterograde amnesia, but not much retrograde amnesia.
§ Often accompanied by retrograde amnesia (less common to find the reverse).
Brain trauma effect on memory
§ Brain trauma: damage to the brain which can be caused by traumatic head injury, disease, seizure, malnutrition, stroke, chemical damage due to drugs (incl. alcohol), anoxia (damage due to lack to oxygen), surgery, etc.
§ Head injuries are common forms of brain damage that lead to amnesia.
§ Concussion (loss of consciousness for a period of time) may lead to temporary or permanent memory loss, or permanent brain damage.
§ Mild concussion disrupts consolidation process, causing anterograde amnesia for the events just prior to the occurrence of the head injury.
Dementia
§ Dementia: refers to a large group of neurodegenerative diseases that causes deterioration of mental abilities in memory, language and reasoning; may be caused by disease or brain damage.
Alzheimer’s disease general
§ Alzheimer’s disease: a disease that is caused by a widespread degeneration of brain neurons, causing progressively severe deterioration of mental ability, personal skills and behaviour.
§ Incurable and primarily impairs memory and other cognitive functions.
§ No diagnostic test, an accurate diagnosis can only be made after death where the examination of the brain tissues can be conducted.
§ Causes both anterograde amnesia (hippocampus is affected) and retrograde amnesia (prefrontal cortex is affected).
Alzheimer’s structural changes
§ Presence of amyloid plaques (proteins deposits that form on axon terminals) (damages neurons).
§ Build up of neurofibrillary tangles which interrupt their communication (results in death of cells).
§ Lower levels of key neurotransmitter involved in memory (acetylcholine).
§ Hippocampus first to be affected by disease, then other areas in the temporal lobe, which then spread to the frontal lobe and the pre-frontal cortex.
§ Deterioration of neurons in the brain leading to brain tissue shrinkage and brain tissue death.
Alzheimer’s change t memory
§ Memory loss, personality and mood changes, confusion, disorientation, impaired attention and poor judgement
§ Loss of functions (e.g. ability to talk, walk and control the bladder).
§ Initially impaired declarative memory (early symptom).
§ Severe decline in working memory (STM), episodic, semantic and procedural memories.
§ Anterograde amnesia symptoms.
§ Loss of the ability to learn new tasks
§ Impaired ability to recognise close family and friends.
