Wernicke and Broca aphasia vs Conduction aphasia
How to tell Wernicke and Broca aphasia and Conduction aphasia apart when a board question makes them look alike.
Wernicke is fluent but does not understand; Broca understands but cannot speak fluently; conduction understands and speaks fluently but cannot repeat.
Side by side
Wernicke aphasia has fluent nonsensical speech with poor comprehension; Broca aphasia has nonfluent effortful speech with relatively preserved comprehension.
Conduction aphasia has fluent speech and good comprehension but markedly impaired repetition, classically from arcuate fasciculus or dominant perisylvian connection lesions.
Dominant posterior superior temporal injury impairs language comprehension in Wernicke aphasia; dominant inferior frontal injury impairs speech production in Broca aphasia.
Disconnection between comprehension and production networks impairs repetition despite preserved comprehension and fluent output.
Wernicke aphasia (fluent, poor comprehension, paraphasic errors, often with right superior visual quadrantanopia) localizes to the dominant superior temporal gyrus in the inferior MCA division; Broca aphasia (nonfluent, intact comprehension, agrammatic effortful speech, often with right hemiparesis) localizes to the dominant inferior frontal gyrus in the superior MCA division.
Conduction aphasia (fluent, intact comprehension, disproportionately impaired repetition with phonemic paraphasic errors that the patient recognizes and tries to correct) localizes to the arcuate fasciculus or supramarginal gyrus, deep to the dominant parietal cortex. The deficit is the disconnection between Wernicke and Broca areas.
The trap
Speech that sounds normal on the opening greeting does not rule out aphasia. Conduction aphasia preserves fluency and comprehension, so the defect only surfaces on repetition testing. Ask the patient to repeat 'no ifs, ands, or buts' or 'today is a sunny day in Boston' verbatim. Conduction aphasia produces phonemic paraphasic errors during repetition while the patient knows the errors are wrong and tries to correct them.
The repair move
For every aphasia stem, run three tests in fixed order: fluency (does speech flow), comprehension (can the patient follow a two-step command), and repetition (repeat a short phrase). The 2x2 grid: fluent + good comprehension + bad repetition is conduction aphasia (arcuate fasciculus); fluent + bad comprehension + bad repetition is Wernicke (posterior superior temporal gyrus); nonfluent + good comprehension + bad repetition is Broca (inferior frontal gyrus); nonfluent + bad comprehension + bad repetition is global aphasia.
Try a free question
CoreA patient speaks fluently but produces nonsensical sentences and cannot follow spoken commands after a dominant temporal stroke. Which aphasia is most likely?
Show answer and explanation
Answer: A. Wernicke aphasia. Fluent speech with poor comprehension supports Wernicke aphasia.
Why the other choices are tempting
- B. Broca aphasia is nonfluent with relatively preserved comprehension.
- C. Conduction aphasia has preserved comprehension but impaired repetition.
- D. Global aphasia impairs fluency and comprehension severely.
- E. Dysarthria is motor articulation impairment rather than language comprehension deficit.
Flashcards
Tap a card to flip it.
What pattern points to Wernicke aphasia?
Fluent nonsensical speech with poor comprehension points to Wernicke aphasia.
What pattern points to Broca aphasia?
Nonfluent effortful speech with relatively preserved comprehension points to Broca aphasia.
Quick answers
What is the fastest way to tell Wernicke and Broca aphasia from Conduction aphasia?
Wernicke is fluent but does not understand; Broca understands but cannot speak fluently; conduction understands and speaks fluently but cannot repeat.
What is the key clue for Wernicke and Broca aphasia?
Wernicke aphasia has fluent nonsensical speech with poor comprehension; Broca aphasia has nonfluent effortful speech with relatively preserved comprehension.
What is the key clue for Conduction aphasia?
Conduction aphasia has fluent speech and good comprehension but markedly impaired repetition, classically from arcuate fasciculus or dominant perisylvian connection lesions.
What is the common trap with Wernicke and Broca aphasia vs Conduction aphasia?
Speech that sounds normal on the opening greeting does not rule out aphasia. Conduction aphasia preserves fluency and comprehension, so the defect only surfaces on repetition testing. Ask the patient to repeat 'no ifs, ands, or buts' or 'today is a sunny day in Boston' verbatim. Conduction aphasia produces phonemic paraphasic errors during repetition while the patient knows the errors are wrong and tries to correct them.