Aphasia is not simply a sensory or motor deficit. Language has 6 broad components. Fluency,Naming,Comprehension,Repetition,Reading and Writing. Fluency,comprehension and repetition has some localizing values.
1. Broca`s aphasia - fluency and repetition impaired. Comprehension intact. Of note, broca`s aphasia can have some impaired comprehension, particularly syntactically dependent sentences.For eg ." The lion was killed by the tiger" . They often incorrectly choose tiger as the dead animal. Prosody is also lost.
2.Wernicke`s aphasia - Compehension and repetiton impaired. Fluency intact.Lots of paraphasic errors. Neologism.
In Broca`s aphasia the patient is frustated, in Wernicke`s aphasia the examiner is frustated.
3.Conduction aphasia - Repetition only impaired. Comprehension and fluency intact.
4. Transcortical aphasia - resembles Broca`s, Wernicke`s but repetition is spared. Seen in watershed infarcts. Can be subdivided into Transcortical sensory aphasia if comprehension is impaired or Transcortical motor if fluency is impaired but comprehension is intact.
5. Global aphasia - Repetition,comphresion and fluency impaired.Seen in large Left MCA infarct.
Ref : Neuroanatomy - Hal Blumenfeld
