Fractionation of Memory
in Medial Temporal Lobe
Amnesia
Chris M. Bird
Tim Shallice
Lisa Cipolotti
Who?
RH
 Female
 58-year-old housewife
 Right-sided hippocampal damage
 Intact cognitive profile apart from
selective memory impairments

What Went Wrong?

1996




Sudden onset tingling, weakness in the left arm
Impairment in remembering events, appointments,
conversations
Difficulty with her sense of direction – esp. in unfamiliar
places
However



NO difficulty in remembering names & faces
NO difficulty in recognizing familiar places or landmarks
Neurological examination - normal
Nature of the Damage

T1 weighted images



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selective atrophy of right hippocampal formation (focused
volume loss)
Enlargement of the right lateral ventricle
NO abnormalities in left hippocampus
Other temporal lobe areas appeared normal
Nature of the Damage




Brain volume calculated to be within normal
range  no evidence of widespread atrophy
Left hippocampus volume = 2654 mm3
Right hippocampus volume = 1100 mm3
Right hippocampus markedly small – 58.6%
smaller
Specific Aspects of Memory
Impaired

2 assessments, 1 year apart


March 2003 & March 2004
Results

General Cognitive Assessment


Verbal & Performance IQ – remarkably similar scores
Nominal Skills, Visual, & Visuospatial perception –
normal


GNT, Object decision, Cube analysis, Number location
Executive processing – normal

WCST, Verbal fluency
Specific Aspects of Memory
Impaired

Results

Semantic Memory Assessment



Category specific naming test – normal
Able to name all famous buildings, 9/12 famous faces
Category fluency – normal



8 semantic categories, 3 phonemic categories
3 comprehension tests – satisfactory
Intact performance on general intelligence, focal
language, perception, executive tasks, and
extensive semantic memory battery  no
cognitive decline
Specific Aspects of Memory
Impaired

Results

Anterograde memory assessment



Story recall tests – weak
Paired associate learning test – lower end of normal
range
Visual recall – clearly impaired



Rey-Osterreith complex figure
Failed at learning a spatial supraspan
Recognition Memory Test – normal

Suggests preserved recognition memory for verbal material
& unfamiliar human faces
Specific Aspects of Memory
Impaired

Results

Anterograde memory assessment cont’d

Topographical Recognition Memory Test – poor



Pictures of outdoor urban scenes
Overall, verbal recall & recognition memory
(human faces) tests – normal range
Tests of story recall - poor
Specific Aspects of Memory
Impaired

Results

Doors & People Test

Verbal Subtests




Visual Subtests


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Immediate – intact
Delayed – impaired
Recognition – satisfactory
Immediate – impaired
Intact verbal recall & recognition memory
Impaired visual recall
What can we learn from this?



Left hippocampus is sufficient to serve both
recollection & familiarity of some verbal
memoranda
Right hippocampus necessary for recollection
& familiarity for topographical materials
Recognition memory for unknown faces not
dependent on hippocampus, may depend on
other structures
Discussion

Outlook


Data from this study
appear to support earlier
studies that
hippocampus plays role
in both recollection &
familiarity
Word of caution on
drawing strong
conclusions about the
neuroanatomy of
recollection & familiarity

Unclear


Which aspects of nonverbal memory can be
mediated successfully by
areas outside the
hippocampus?
What treatments are out
there that can improve,
possibly bring back, nonverbal memory abilities in
patients with extensive
MTL damage?
Questions?