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

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