Amnesia Flashcards

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1
Q

Patient HM (Henry Molaison)

A

Had Bilateral removal of the hippocampus to treat epilepsy

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2
Q

What did HM suffer from?

A

Severe Amnesia
* unable to remember events since operation (anterograde amnesia)
* loss of personal memories up to 11 years prior to surgery (retrograde amnesia)

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3
Q

What aspects of HM’s memory were preserved?

A
  • short-term memory
  • knowledge of previously-acquired facts (semantic memory)
  • motor skill learning; perceptual learning; non-declarative (non-conscious) memory
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4
Q

but what was wrong with HM’s brain?

A

visually all anterior hippocampus and surround cortex removed bilaterally, plus amygdala

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5
Q

what happens when there’s damage to the hippocampus?

A

As the hippocampus is a key part of the network - damage to these associated structures cause amnesia
* there must be bilateral damage affecting these structures in both hemispheres
most patients have less specific damage than HM. This causes a broader range of deficits beyond episodic memory

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6
Q

what is the hippocampus linked to?

A

episodic memory (as decovered from specific brain removal from HM) -> image to hippocampus leads to amnesia but more / less specific damage may lead to broader deficits

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7
Q

what does anterior temporal damage lead to?

A

problems with semantic memory and language

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8
Q

what does prefrontal damage lead to?

A

problems with retrieval and personality

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9
Q

what is herpes simplex encephalitis?

A

Herpes simplex virus spreads from the face along cranial or olfactory nerves to the brain

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10
Q

who was affected by HSE?

A

Clive Wearing and Patient EP (Insausti et al., 2013) are examples of relatively pure cases of amnesia following HSE

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11
Q

what does HSE usually affect?

A

typically focussed in medial and anterior areas (including hippocampus), there is often also damage to anterior temporal and inferior medial frontal cortex.

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12
Q

what are the first symptoms of HSE?

A

fever, confusion, epileptic seizures, anterograde and retrograde amnesia

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13
Q

what are later symptoms of HSE?

A
  • semantic deficits (category-specific - trouble with knowledge and name retrieval for animals and people)
  • often wide spread damage and deficits
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14
Q

What is Hypoxic Brain Injury?

A

Brain cells start to die after 4-6 minutes of oxygen deprivation. The brain is 2% of the body’s weight yet uses 20% of its oxygen

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15
Q

What are the effects of Hypoxic Brain Injury?

A

individuals who survive an hypoxic episode often have amnesia -> contained to the hippocampus because the brain relies mostly on oxygen here -> quite similar to pure amnesia and only affects episodic memory

  • effects of hypoxia are especially severe in the hippocampus as these cells use a lot of oxygen
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16
Q

What did Zola Morgan et al., 1986 find as a result of patient RB?

A

causes of hypoxic brain injury include heart attack, respiratory failure, carbon monoxide posioning and disruption in brain flow to the brain i.e. following a haemorrhage

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17
Q

what areas does a hypoxic episode effect?

A

bilateral hippocampus

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18
Q

what do neurones in the hippocampus require oxygen

A

highly metabolically active so will be particularly affected by oxygen deprivation

19
Q

what are the effects of hypoxic episode?

A
  • pronounced anterograde and some retrograde amnesia
    BUT other mental functions are spared (incl semantic memory and language)
20
Q

What is Korsakoff’s syndrome?

A

amnesia associated with long-term alcoholism

21
Q

what is Korsakoff’s syndrome caused by?

A
  • thiamine (vitamine B1) deficiency
  • Drinkers may neglect their diet
  • Alcohol interferes with conversion of thiamine into active form
  • Alcohol reduces absorption and storage of vitamins
22
Q

What damage does Korsakoff’s syndrome cause?

A

Wide-spread damage to the brain: Mammillary bodies are severely affected, plus prefrontal cortex

PFC damage produces problems beyond ‘pure’ amnesia:
* Behavioural changes i.e. apathy
* Problem with retrieval as well as memory formation

23
Q

how can we help retrieval in Korsakoff’s syndrome?

A

retrieval can be cued

24
Q

How may we be able to treat Korsakoff’s syndrome?

A

doses of intravenous thiamine (but has to be done quickly)

25
Q

Why don’t those with Korsakoff’s syndrome usually care about treatment?

A

damaged prefrontal cortex means they have emotional issues (apathy and flat emotional effect) -> don’t really care about treatment as a result of a behavioural change

26
Q

what is Korsakoff’s syndrome often preceded by?

A

Wernicke’s Encephalopathy

27
Q

What is Wernicke’s Encephalopathy

A

state of confusion with deficits in motor control
* Anterograde and Retrograde amnesia
* Retrival problems
* Confabulation: difficulty separating real memories from imagination
* Personality changes (apathy and flat emotional affect)

28
Q

what are early symptoms of Alzheimer’s disease?

A

problems with memory, language, decision-making and planning/reasoning
* some overlap with ‘pure’ amnesia but there is also a deficit in intellectual function

29
Q

What are skills we look at when looking at amnesia?

A
  • Anterograde Amnesia
  • Retrograde Amnesia
  • Semantic Memory
  • Working Memory
30
Q

Anterograde Amnesia

A

inability to acquire new memories

31
Q

Retrograde Amnesia

A

loss of memories from before injury

32
Q

Semantic Memory

A

Factual Knowledge

33
Q

Working Memory

A

keeping information active by repeatedly think about it

34
Q

Face Recognition [From Wechsler Memory Scale]:
* Patient is shown a sequence of 60 faces, one at a time.
* They are then shown a second sequence of faces and have to decide whether they have seen each one before.
* This is a test of recognition (as opposed to recall). Both recognition and recall are normally impaired in amnesia.
Chance rate is 50%.

What skill does this tap into?

A

recognition and anterograde memory

35
Q

Picture Naming:
* Patient is shown pictures one at a time and asked to say what they are called. This is a very simple task that gives us a lot of information.
* Some patients can show different degrees of impairment for animals and man-made objects (i.e., category-specific impairment). This might reflect the fact that our knowledge of animals draws heavily on visual features (e.g., the difference between a zebra and a horse is the stripes) while man-made objects have more manipulable features that we feel and move.
* Healthy participants are typically able to name the vast majority of these sorts of pictures – their accuracy is near ceiling.

Errors can be informative:
* Semantic errors – e.g., cat à “dog”
* Phonological errors – e.g., cat à “cad”

What skill does this tap into?

A

Semantic memory

36
Q

Rey Figure Copy:
The patient first copies the complex figure at the top when it is in front of them. This is the ‘immediate’ condition. 15 minutes later, they are asked to reproduce this figure from memory. To do this, they have to remember seeing the test, so patients with severe amnesia often can’t attempt the delayed copy.

what skill does this tap into?

A

anterograde

37
Q

Corsi Blocks Test:
* The examiner sits looking at the numbers; the patient is on the other side of the desk and can’t see the numbers. The examiner taps out a sequence on the top of the blocks, such as 2-8-3. The patient then tries to tap the same blocks, in the same order. The sequences start very short (i.e., just two blocks) and get longer. Testing stops once the patient reliably makes errors, and the sequence length that they can reproduce accurately is called their “span”. Healthy participants can tap a sequence of 5-7 blocks.
* This test is often used in conjunction with digit span (repeating a sequence of numbers aloud in the same order you heard them).

What skill does this often tap into?

A

anterograde

38
Q

Paired-associate learning:
* This is a very simple test that measures verbal learning and forms a core part of the Wechsler Memory Scale (WMS). Participants hear a series of 12 word pairs and then, in the test phase, they hear one of the words and are asked to say the word that was paired with it.
* This test can also be used to distinguish between memory disorders that result from (i) encoding/storage deficits and (ii) retrieval difficulties. If encoding/storage are profoundly impaired, as in HM, the information cannot be recovered even if cues are provided (e.g., what went with Chair – it started with “card….”). However, these cues are very helpful if patients are having difficulty selectively retrieving the right word. We are using this method in our research.

What skills does this tap into?

A

Anterograde, a bit of working memory and verbal memory

39
Q

Pyramids and Palm Trees (PPT):
The patient is asked to decide which of the two items at the bottom of the page goes with the top item. The trials are presented as either pictures or words. Typically, a patient completes both versions of this test on different days.

What skill does this map into?

A

anterograde

40
Q

Autobiographical Memory Interview
* The patient is asked to describe a memory that is jogged by each word. For example, if I heard the word RIVER, I might think about the picnic I went on with my friends in Oxford a few years ago when the children were small and how we made a pretend pie with grass seeds.
* An attempt is made to work out when the memories date from – with the help of the patient’s family. The memories from different decades of the patient’s life can then be counted up.
* **The graph shows the normal pattern in red and representative data for a patient with amnesia, who is 46 years old, in blue. Healthy people also tend to report a lot of recent memories, while people with amnesia do not. Both healthy people and those with amnesia show a “reminiscence bump” – lots of memories from the teenage and early adult years; perhaps because memorable things happen in those decades, such as falling in love and leaving home.
* Researchers can also study the quality of memories. My memory about the picnic is detailed and specific, while someone with amnesia might just say “I had some nice food by the river”, which is vague and doesn’t suggest any real recollection.

What skill does this tap into?

A

Retrograde

41
Q

Which two disorders have broader intellectual problems?

A

Alzheimer’s and Kor

42
Q

What might be the best test(s) to detect anterograde amnesia and why?

A

Rey Figure Copy -> isn’t reliant on the individual having sufficient semantic knowledge

43
Q

Who has a severe semantic deficit?

A

Herpes