This condition is suffered by patients who suffer damage to
Wernicke’s area, located in the posterior superior
temporal lobe. Patients with this condition have been found, in non-verbal tasks which require a subject to point at objects in response to a
question, to have poor comprehension of
speech.
Sufferers can still produce speech, but although words are produced fluently their utterances have no real meaning, or at least the true meaning is too garbled and disrupted to make sense. Apparently patients are unaware that they do not understand what people are saying to them, since they never display any signs of confusion, and they respond to questions, albeit in an incomprehensible way. They seem to understand the non-verbal aspects of communication such as facial expressions and intonation (they know when a question has been asked from the rising intonation of the questioner). They also follow all the rules of normal conversation, such as turn taking.
Wernicke’s area is in the auditory association cortex, which implies that it is involved with the association of the sequences of sounds which make up words. This was Wernicke’s suggestion, and it has since been corroborated with MRI and CT techniques. This means that not only are patients unable to recognise spoken words and give them meaning, they cannot associate these sounds to create meaningful speech of their own