Language Disorders

Three major types of Aphasia Rosenzweig: Table 19.1, p. 615

• Borca’s aphasia
• Nonfluent speech
• Wernicke’s aphasia
• Fluent speech but unintelligible
• Global aphasia
• Total loss of language
• Others: Conduction, Subcortical, Transcortical Motor/Sensory (see also Kandel, Table 59-1)

• Brain areas involved in Language

Broca’s Aphasia Brodmann 44, 45

• Lesions in the left inferior frontal region (Broca’s area)
• Nonfluent, labored, and hesitant speech
• Most also lost the ability to name persons or subjects (anomia)
• Can utter automatic speech (“hello”)
• Comprehension relatively intact
• Most also have partial paralysis of one side of the body (hemiplegia)
• If extensive, not much recovery over time

Wernicke’s Aphasia Brodmann 22, 30

• Lesions in posterior of the left superior temporal gyrus, extending to adjacent parietal cortex
• Fluent speech
• But contains many paraphasias
• “girl”-“curl”, “bread”-“cake”
• Syntactical but empty sentences
• Cannot repeat words or sentences
• Unable to understand what they read or hear
• Usually no partial paralysis

Wernicke-Geschwind Model 1. Repeating a spoken word

• Arcuate fasciculus is the bridge from the Wernicke’s area to the Broca’s area

Wernicke-Geschwind Model 2. Repeating a written word

• Angular gyrus is the gateway from visual cortex to Wernicke’s area
• This is an oversimplification of the issue:
• not all patients show such predicted behavior (Howard, 1997)

Sign Languages

• Full-fledged languages, created by hearing- impaired people (not by Linguists):
• Dialects, jokes, poems, etc.
• Do not resemble the spoken language of the same area (ASL resembles Bantu and Navaho)
• Pinker: Nicaraguan Sign Language
• Another evidence of the origins of language (gestures)
• Most gestures in ASL are with right-hand, or else both hands (left hemisphere dominance)
• Signers with brain damage to similar regions show aphasia as well