LANGUAGE

• language includes the understanding of the spoken and printed word and expressing ideas in speech and writing
• Human language functions depend more on one cerebral hemisphere than on the other
• dominant hemisphere


  concerned with categorization and symbolization
• nondominant hemisphere


  specialized in the area of spatiotemporal relations
• non dominant hemisphere


  involved in the identification of objects by their form and the recognition of musical themes and in facial recognition
• In 96% of right-handed individuals (91% of the human population), the left hemisphere is the dominant or categorical hemisphere

  
  

  The remaining 4%, the right hemisphere is dominant
• In 70% of left-handed individuals, the left hemisphere is the dominant hemisphere

  
  

  In 15% of left-handed persons, the right hemisphere is the categorical hemisphere

  
  

  In remaining 15%, there is no clear lateralization
• wernicke area


  concerned with comprehension of auditory and visual information
• wernicke area regions at the posterior end of the superior temporal gyrus
• wernicke area projects via the arcuate fasciculus to the Broca area in the frontal lobe immediately in front of the inferior end of the motor cortex.
• broca area


  processes the information received from Wernicke area into a detailed and coordinated pattern for vocalization and then projects the pattern via a speech articulation area in the insula to the motor cortex
• broca area


  initiates the appropriate movements of the lips, tongue, and larynx to produce speech
• angular gyrus


  behind the Wernicke area appears to process information from words that are read in such a way that they can be converted into the auditory forms of the words in Wernicke area
• aphasias


  abnormalities of language functions not due to defects of vision or hearing or to motor paralysis.
• aphasias


  caused by lesions in the categorical hemisphere
• A lesion of Broca area causes a nonfluent aphasia denoted as an expressive or motor aphasia
• broca's aphasia

  have slow speech and difficulty in generating verbal or written words
• In Broca's Aphasia, sometimes the words retained are those that were being spoken at the time of the injury or vascular accident that caused the aphasia
• Wernicke Area


  produces a type of fluent aphasia in which speech itself is normal but it is full of jargon and neologisms that make little sense.
• wernicke area


  patient fails to comprehend the meaning of spoken or written words, so other aspects of the use of language are compromised.
• anomic aphasia


  When a lesion damages the angular gyrus in the categorical hemisphere without affecting Wernicke or Broca areas
• In anomic aphasia, there is no difficulty with speech or the understanding of auditory information. Instead, there is trouble understanding written language or pictures, because visual information is not processed and transmitted to Wernicke
• stuttering


  associated with right cerebral dominance and widespread elevated activity in the cerebral cortex and cerebellum including increased activity in the supplementary motor area