Types of Aphasia

Ling 411 – 05

Simple Functions / Complex Functions: Speaking and Understanding

• How is simplicity/complexity determined?

• What about "understanding speech“? • A simple process, localized in Wernicke's area? • Actually it is a pretty complex process

• Similarly, “speaking”• Pretty complex, not just Broca's area• Uses not just Broca’s area but also Wernicke’s area• Without a properly functioning Wernicke’s area, speech is erratic

Simple Functions / Complex Functions

Simple function

Complex function

Simple Functions / Complex Functions

Speaking vs. Phonological Production• Phonological production is one part of speaking

– located in Broca’s area• Speaking is a complex process

Phonological production plus planning what is about to be produced – involves Wernicke’s area

Understanding speech vs. phonological recognition• Phonological recognition is one part of speech

understanding – located in Wernicke’s area• Speech understanding is a complex process

Includes grammatical and semantic activity Motor activity (Broca’s area) also contributes

Basic functions and complex functions – speaking

Phonological recognition is a basic function Located in Wernicke’s area

• along with, perhaps, the area intermediate between primary auditory area and W’s area

Speaking is a complex function• It is a cooperative effort of several areas,

including Broca’s area and Wernicke’s area• Phonological recognition is a necessary

component of speaking

Major Types of Aphasia according to A. Damasio

Wernicke’s aphasia Broca’s aphasia Transcortical sensory aphasia Transcortical motor aphasia Conduction aphasia Global aphasia Anomic aphasia Alexia with agraphia Alexia without agraphia Pure word deafness

Wernicke’s Aphasia

Impaired comprehension• Result of failures in phonological discrimination

Fluent verbal output Augmented verbal output

• Extra syllables at ends of words• Extra words at ends of phrases• Extra phrases at ends of sentences

Augmentations usually nonsensical Syntax otherwise not too bad Verbal paraphasia, including neologisms

Areas of damage in Wernicke’s aphasia

Always involved:• Posterior superior temporal gyrus

The classical core of Wernicke’s area Usually also involved:

• More of superior temporal gyrus• Middle temporal gyrus• Temporal plane*

Often also involved:• Angular gyrus• Supramarginal gyrus• Temporal-occipital junction area

*can be considered part of superior temporal gyrus

Definitions of Wernicke’s area

1. Narrow definition Posterior superior temporal gyrus Including adjacent temporal plane

and superior temporal sulcus

2. Broad definition (used by some)• Includes also angular gyrus and/or

supramarginal gyrus• Better term for this broader area:

‘Posterior language area’

Principal cortical gyri (schematic)Review

Subtypes of Wernicke aphasia

Not discretely different• Rather, spans along a scale

Type I• Damage is more anterior• Phonological recognition most affected• “Word deafness”

Type II• Damage is more posterior, incl. angular gyrus• More word-blindness than word-deafness

I.e., alexia Intermediate types also occur “Obviously, all subtypes of Wernicke aphasia are

variations on a continuum…” •

(Benson&Ardila:144)

Wernicke’s Aphasia examples

http://www.youtube.com/watch?v=B-LD5jzXpLE&feature=related http://www.youtube.com/watch?v=aVhYN7NTIKU

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