From verbal nonfluency to interactive fluency in Broca’s aphasia

Our knowledge, how the brain controls and interrelates gesture and speech, is still limited. An interesting branch of the study has been the relationship between aphasia and nonverbal behaviour. The main feature of aphasia is the impairment of communication via natural language. One of the most significant questions is, whether gestures may substitute or compensate for speech in the event of speech disturbance. Several investigators have found that aphasic speakers use more nonverbal behaviours than do normal speakers and many of these studies suggest that aphasic speakers compensate for their verbal deficit by increasing the frequency of their nonverbal behaviour (see e.g. Klippi 1996). In addition, some researchers suggest that the type of aphasia relates to the type of gestures used in communication. It is claimed that Broca’s aphasics use more simple, unelaborated nonverbal units with a high degree of referentiality, which is in accordance with their verbal output, whereas Wernicke’s aphasics have gestures that are vague and uninterpretable like their speech (see e.g. McNeill 1992). On the other hand, e.g. Glosser et al. (1986) provided evidence that aphasic speakers are impaired in their gestural communicative competence under natural conditions of communication.