Causes of memory loss: CTE, Alzheimer's disease and Wernicke-Korsakoff Syndrome (WACE Year 12 Psychology Unit 3)

What this dot point is asking

For each condition you should know the cause, the effect on memory (which types and in what order), and the impacts on behaviour and emotion. Questions may ask you to compare them or to apply them to a case.

Key terms

• Anterograde amnesia: inability to form new long-term memories after the onset of damage.
• Retrograde amnesia: loss of memories formed before the onset of damage.
• Confabulation: filling gaps in memory with invented details, without intending to lie.

Trauma: Chronic Traumatic Encephalopathy (CTE)

• Cause: repeated blows to the head, including concussions and repeated smaller impacts that do not cause symptoms at the time, common in contact sports (such as Australian football, rugby and boxing) and some military service.
• What happens in the brain: a progressive degenerative disease in which an abnormal form of tau protein builds up around blood vessels and spreads through the brain, damaging neurons. It can only be confirmed by examining the brain after death.
• Effects on memory: gradually worsening memory problems, especially for recent events, along with poor concentration and, later, dementia.
• Impacts on behaviour and emotion: impulsivity, aggression and irritability, depression, anxiety, apathy and difficulty with planning and decision-making. Symptoms may appear years after the head impacts stopped.

Degeneration: Alzheimer's disease

• Cause: a progressive neurodegenerative disease and the most common form of dementia. Its main risk factor is age.
• What happens in the brain: amyloid plaques (clumps of beta-amyloid protein between neurons) and neurofibrillary tangles (twisted tau protein inside neurons) disrupt communication and kill neurons. The damage usually begins in the hippocampus and nearby areas, then spreads across the cortex, and the brain shrinks.
• Effects on memory: early difficulty forming new memories (anterograde amnesia), such as repeating questions or forgetting recent events; later loss of older memories (retrograde amnesia), language, reasoning and recognition of familiar people. Procedural memories tend to last longer.
• Impacts on behaviour and emotion: confusion, getting lost, anxiety, depression, mood swings, agitation, withdrawal from social activity, and in later stages dependence on others for daily care.

Drug induced: Wernicke-Korsakoff Syndrome (WKS)

• Cause: a severe lack of thiamine (vitamin B1), most often from long-term heavy alcohol use, which leads to poor diet and reduces the body's ability to absorb and use thiamine.
• Two stages:
  • Wernicke's encephalopathy: an acute stage with confusion, unsteady walking and abnormal eye movements. It is a medical emergency and can be treated with thiamine.
  • Korsakoff syndrome: a chronic stage with lasting memory impairment.
• What happens in the brain: damage to areas including the thalamus and mammillary bodies, which are part of the brain's memory circuits.
• Effects on memory: severe anterograde amnesia, some retrograde amnesia, and confabulation. Procedural memory and general intelligence may be relatively spared.
• Impacts on behaviour and emotion: apathy, lack of insight into the memory problem, difficulty living independently, and changes in personality.