What is an aphasia?
Disturbance in language as a result of brain damage
How is a language disorder different to a speech disorder?
Speech disorders may be present when language abilities are still intact
eg. dental anaesthesia - difficult to speak
What are some of the causes of aphasia?
Acute onset: stroke, penetrating head injury, surgical resection
Insidious onset: dementia, neoplastic change
Paroxysmal-episodic: focal seizures, migraine
Describe the lateralisation of language?
Left hemispheric dominance
95% of right handers and 70% of left handers have left lateralised language
Describe the role of the right hemisphere in language?
May play a role in non-propositional speech, prososdy and paralinguistic aspects of speech
What is the arterial supply to the language areas of the brain?
Middle cerebral artery - superior and inferior divisions
What do the superior and inferior divisions of the middle cerebral artery supply?
Describe the difference between language production and language selection?
Production: producing appropriate output sequences
Selection: choosing appropriate content
Which aspects of language (production or selection) are fluent and non-fluent language disorders associated with?
Describe the major differences between fluent and non-fluent aphasias?
Which type of language disorders are Broca's and Wernicke's aphasias?
Broca's aphasia: non-fluent aphasia
Wernicke's aphasia: fluent aphasia
What is the arcuate fasiculus?
A hypothetical tract that is thought to link Broca's and Wernicke's areas
Describe the characteristics of Wernicke's aphasia?
Fluent, jargonistic language
No motor weakness
Describe the characteristics of Broca's aphasia?
Non-fluent, highly effortful language
Right face and arm weakness
What is conduction aphasia?
Fluent aphasia, but more meaningful than Wernicke's type
Intact basic auditory comprehension
Poor repetition of words
What is transcortical motor aphasia?
Muteness at most severe
Describe the mechanisms of recovery from aphasias?