University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

288

Pages:

4
Author:

Mariam A.

Aphasia     Symptoms include: o Problems with fluency, articulation, word-finding and repetition. o Problems producing and comprehending complex grammatical structures, both orally and in writing. o Patients with more severe pathology can only articulate the same recurring sounds, words or phrases that are uttered each time they attempt to speak. Clinical syndromes in language processing reflect disorders in cognitive processes, brought about by an underlying pathology at various sites within the brain. Due to the interconnections between various brain sites involved in language, damage to one area can have effects on other areas. Be wary of interpretation of direct electrical stimulation; electrical stimulation of the same site can produce positive as well as negative behavioural responses. Models of speech  State feedback control model: o Typically include a motor controller that sends commands to a motor effectors, which in turn results in a change of state detected by sensory systems. o An internal forward model receives a copy of the motor command, generates a prediction of the sensory consequences of the command and compares it to the measured sensory consequence.  Psycholinguistic models: o Two major linguistic stages of processing. o Word (or lemma) state: abstract word form without phonological specification is coded. o Phonological stage: phonological form of the word is coded.  Combining both makes the hierarchical state feedback control. Classification of aphasias  Expressive (motor) or receptive (sensory)  However, deemed to be overly simplistic and inaccurate. Assessment of aphasias  A picture can be used to elicit conversation.  Patient can be asked to read a text passage to assess comprehension. Acute aphasia  Broca’s aphasia (left inferior frontal infarction): inability to produce motor commands that control muscles of speech.  Wernicke’s aphasia (left temporo-parietal infarction): inability to comprehend language. Progressive aphasia    Semantic dementia: common words are often forgotten. Progressive nonfluent aphasia: know what it is, but trouble finding the word for it. Alzheimer’s disease (logopenic aphasia): slow speech, and impaired syntactic comprehension and naming.