When Words Fail: Aphasias and language disorders

Broca’s area

in left inferior frontal gyrus - speech production, language planning and syntactic processing

aphasia

a language disorder affecting speech production or comprehension.

Broca’s aphasia

damage to Broca’s = non-fluent effortful speech. short, broken sentences with poor grammar. comprehension maintained

Wernicke’s area

left posterior superior temporal gyrus - language comprehension and semantic processing

Wernicke’s aphasia

damage to wernicke’s = fluent but meaningless speech and impaired understanding

specific language impairment

developmental disorder characterised by delayed language acquisition affecting receptive and/or expressive language, despite otherwise normal development.

• 50% comordibility with dyslexia

• treatment- speech therapy

possible cause for SLI

Auditory Temporal Sampling Hypothesis, suggesting impaired processing of rapid auditory information (also proposed in dyslexia).

stuttering

repeated movements and fixed postures of speech mechanisms. runs in families suggesting genetic component

• unknown cause - inset in childhood

• stutterers don’t differentiate in any other ways from non except for presence of social anxiety

• recovery unclear - more likely in girls and better if recovery starts soon after onset

possible causes for stuttering

• stronger activation in right motor area = interruptions in speech-motor patterns

• may fail to develop LH control (dominance) of speech - bilateral activation in stutterers

• timing and motor control by cerebellum is impaired

williams syndrome

genetic disorder - spontaneous deletion of 26-28 genes on chromosome 7

• mental retardation

• below average visuo-spatial skills

• poor social cognition

• relatively normal language skills = huge discrepancy in IQ and language skills