Speech perception
Agnosia is "the loss or diminution of the ability to recognize familiar objects or stimuli usually as a result of brain damage". There are several different kinds of agnosia that affect every one of our senses, but the two most common related to speech are speech agnosia and phonagnosia.
Fast mapping
Fast mapping in individuals with aphasia has gained research attention due to its effect on speaking, listening, reading, and writing. Research done by Blumstein makes an important distinction between those with Broca's aphasia, who are limited in physical speech, as compared to those with Wernicke's aphasia, who cannot link words with meaning. In Broca's aphasia, Blumstein found that whereas individuals with Wernicke's aphasia performed at the same level as the normal control group, those with Broca's aphasia showed slower reaction times for word presentations after reduced voice onset time stimuli. In short, when stimuli were acoustically altered, individuals with Broca's aphasia experienced difficulty recognizing the novel stimuli upon second presentation. Bloomstein's findings reinforce the crucial difference between one's ability to retain novel stimuli versus the ability to express novel stimuli. Because individuals with Wernicke's aphasia are only limited in their understanding of semantic meaning, it makes sense that the participant's novel stimulus recall would not be affected. On the other hand, those with Broca's aphasia lack the ability to produce speech, in effect hindering their ability to recall novel stimuli. Although individuals with Broca's aphasia are limited in their speech production, it is not clear whether they simply cannot formulate the physical speech or if they actually did not process the stimuli.