Transcript M.S. a case of autobiographical amnesia and visual memory loss

M.S.: a case of autobiographical
amnesia and visual memory loss
(D.L Greenberg, M.J. Eacott, D. Brechin, and D.C. Rubin)
By Christina Schulte
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M.S. is a 60 year old, left-handed, British
male. He works at a REMPLOY factory and is
semi-independent. He scores average on
WAIS for verbal IQ (101) and above average
mental arithmetic on WAIS-R (14).
While a 23 year old police cadet in 1970 he
was diagnosed with herpes encephalitis.
Neuroimaging shows extensive damage to
the occipital and temporal lobes and some
damage to right parietal lobe.
Specific Mental Functionality
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Abnormalities:
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Associative visual agnosia
Prosopagnosia
Achromatopsia
Visual-memory-deficit amnesia (VMDA)
Retrograde amnesia
Anterograde amnesia
He does have:
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Normal visual acuity
Normal linguistic abilities
Near normal semantic memory, including personal semantic knowledge,
(although the author’s note he may have some deficits, especially with items
belonging to living categories.)
Normal executive functioning
Specifically
Right side
Left side
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Temporal: temporal pole,
para-hippocampal gyrus,
hippocampus, amygdala,
& 4th temporal gyrus
damaged.
Occipital: cortex spared
but infra- & suprcalcarine
regions are abnormal.
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Temporal: temporal pole,
2nd, 3rd, 4th temporal gyri,
anterior parahippocampal
gyrus damaged. Amydgala
& hippocampus spared.
Occipitial: cortex and
occipitotemporal junction
destroyed
Parietal: white matter
destroyed but cortex intact
Tests of Mental Imagery
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Top: M.S.’s copy of a rhinoceros
(Graded Naming task). He later failed
to recognize the object he had drawn.
Bottom: Attempts to draw items from
memory. Tree, bird, butterfly, car.
His performance on object recognition
tested by the Category-Specific
Names Test was equally poor. He
recognized 0/30 fruits and 0/30
animals. In a spontaneous naming
test he could only name 16 out of 30
household objects. He recognizes
non-living items much better than
living items.
In name recognition, he is almost at
normal levels, but he is poor at face
recognition due to his prosopagnosia.
Previous studies revealed that he
searches individual characteristics of
the face and cannot see it as a whole.
Tests of Autobiographical Memory
Table 1
MS's performance on the autobiographical memory interview
Childhood Pre-illness Post-illness Recent
Semantic:
15 (16–21) 14 (17–21) 16 (17–21) 18.5 (19–21)
Autobio- :
1 (6–9)
4 (7–9)
3 (7–9)
2 (7-9)
Graphical
(normal range listed in parenthesis)
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He was assesed by a large number of autobiographical memory tests
over the course of 3+ years
When cued with keywords tailored to his past he performed way below
controls. He recalled 31 memories (mostly anterograde) for 48 words
when asked to recall memories from anytime in his life and 17/81 when
asked to restrict his memories to retrograde.
Overall, his results show ‘a severe and global autobiographical deficit.’
Discussion
 The authors’ believe that M.S.’s deficits qualify as an
impaired access to long term visual memories because:
he can copy an image and not recognize it, has difficulty
recognizing common objects and drawing them from
memory, and he has trouble manipulating visual images,
particularly when they involve color, people or mental
rotation.
 The authors further pose that this impairment has
contributed to his loss of autobiographical knowledge.
The loss of his visual regions may disrupt the activation
for Autobiographical retrieval.
 He relies on other forms of memory, like semantic
personal memory, to retrieve information about the past,
but cannot recall specific episodes.
 M.S.’s outlook is fair, his cognitive functions have not
declined or improved over time. The paper does not
discuss the pursuit of any treatment options.
 What is not known is why his RA is different from other
patients with Medial Temporal Lobe damage. His
autobiographical memory is impaired across all
periods of his lifetime, while others usually have
poorer performance for recent past memories, and
better retrieval for older memories.