Some notes on Wernicke’s aphasia and Broca’s aphasia from my Neurobiology class:
Wernicke’s Aphasia (also known as receptive aphasia or fluent aphasia):
-Aphasia is the loss of ability to produce and/or comprehend language
-Wernicke’s aphasia is a fluent aphasia. With this form of aphasia, patients easily generate words, but the statements have little meaning
-Carl Wernicke identified the brain region responsible for this type of aphasia in 1874
-Wernicke’s aphasia patients speak without difficulty, but their words convey little information. Intonations during speech sound normal even though the statements are nonsensical. These patients make frequent paraphasic errors in which they substitute incorrect sounds or words. Based on their responses to simple questions, it is clear that patients with fluent aphasia have limited comprehension of spoken or written language. Wernicke’s aphasia patients are frequently unaware that their speech doesn’t make sense. With Wernicke’s aphasia, it appears as though patients are just making up words (incoherent sentences). They can use some phrases. Most Wernicke’s aphasia patients also have agraphia when they write and alexia when they read.
Broca’s Aphasia (also known as expressive aphasia or non-fluent aphasia):
-Broca’s aphasia is called motor or non-fluent aphasia.
-With this form of aphasia, patients have difficulty generating words.
-Paul Broca identified the brain region responsible for this aphasia in 1863 from a patient who could only say the word “tan”
-Patients with Broca’s aphasia use content words (nouns, verbs, adjectives) but not function words (articles, pronouns, conjunctions), they show agrammatism. They struggle to speak words, although they can generate well-practiced statements without obvious difficulty. They have difficulty finding the right noun (anomia). Comprehension is good, but not perfect.
*With Broca’s aphasia, patients have difficulty saying words. They have agraphia (trouble writing), but they can usually read. Language comprehension is easier for them than Wernicke’s patients.
-Comprehension is good but not perfect with Broca’s aphasia. For example, patients with Broca’s aphasia understand from the sentence “Bill chased Mary” (active sentence) that Bill was the chaser and Mary was the person who was chased. Broca’s aphasia patients would have difficulty, however, reaching the correct conclusion hearing the passive sentence “Bill was chased by Mary”. They understand active but not passive sentences.
-Consider the following statements:
1. The banana that the boy is eating is green
2. The boy that the banana is eating is green
You can distinguish between these 2 sentences because one is illogical. Now consider these grammatically equivalent statements:
1. The cow that the monkey is scaring is yellow
2. The monkey that the cow is scaring is yellow
Because of agrammatism, a Broca’s aphasia patient could not identify which animal was scaring the other.