Disorders of High Level Functions: Amnesia, Aphasia,

and Prosopagnosia

Arielle TambiniSPLASH November 21, 2004

MIT Braintrust

Memory

Explicit/semantic Implicit/episodic Long-term Short-term

Amnesia

Causes Retrograde Anterograde Transient global

HM Epilepsy treatment Anterograde amnesia

Long-term explicit memory deficits Short-term intact “You just remember 8. You see 5,

8, 4 add to 17. You remember 8; subtract from 17 and it leaves 9. Divide 9 by half and you get 5 and 4, and there you are – 584.”

Temporal-lobe Amnesia

Intact implicit memories Blinking study Motor tasks Computer programming

Role of hippocampus Imaging studies

Episodic memory deficits

Developmental Loss of blood flow Bilateral hippocampal damage

Prefrontal damage “Childhood amnesia” Aging Korsakoff’s syndrome

Aphasia

Definition Left hemisphere Causes History

Broca’s/nonfluent aphasia

Characteristics Anomia Short sentences Language comprehension

Broca’s area Theories of function

Broca’s/nonfluent aphasia“I asked Mr. Ford about his work before he entered

the hospital.‘I’m a sig… no… man… uh, well,… again.” These

words were emitted slowly, and with great effort. The sounds were not clearly articulated; each syllable was uttered harshly, explosively, in a throaty voice. With practice, it was possible to understand him, but at first I encountered considerable difficulty with this.

‘Let me help you,’ I interjected. ‘You were a signal…”

‘A signal man… right,’ ‘Were you in the Coast Guard?’‘No, er, yes, yes... Ship… Massachu… chusetts…

Coastguard… years.’ He raised his hands twice, indicating the number 19.

Wernicke’s/fluent aphasia

Characteristics Comprehension and production loss Speech

“Nothing the keesereez the, these are davereez and these and this one and these are living. This one’s right in and these are … uh… and that’s nothing, that’s nothing.”

Wernicke’s area Normal function

Aphasias

Broca’s vs. Wernicke’s Apraxia (action) Agnosia (perception)

Other areas Severity

Onset

Aphasias

Handedness Language localization Recovery

Bilingual aphasics Deafness and aphasia? Plasticity

Agnosia

Definition

Prosopagnosia Causes Intact object recognition Recognition of face

Prosopagnosia Face perception

Fusiform Face Area (FFA) Holistic processing Expertise Greeble training