Case Study: Amnesia
anterograde and retrograde
amnesia in a person with bilateral
fornix lesions following removal
of a colloid cyst
AD’s Story
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45-year-old male
no reports of memory loss
complained about severe headaches
discovery of cyst
surgery without complication
woke up confused
Lesions
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bilateral fornix
small spot on basal
forebrain
no damage to
hippocampus
localized and
generally small
Amnesia
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anterograde: LTM
not STM
retrograde:
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lifelong
autobiographical
episodic memory
personal semantic
memory partially
impaired
Dissociation
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remote episodic and semantic memory
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recollection of episodic memories
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recovery of semantic memories
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the role of context
Testing
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WAIS-R: high in average range
WMS-R story recall:
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immediate: impaired
delayed: what test?
AMI:
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episodic severely impaired
semantic slightly impaired
Research
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anterograde: consistent with past studies
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retrograde:
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confirms selective contribution
new evidence for dissociation
contradicts claim regarding lateral neocortex
Outlook & Critique
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some minimal improvement (3 to 9 mo.)
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contribution of basal forebrain lesion?
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lesions avoidable?