Abstract
Lesions to Broca's area cause aphasia characterized by a severe impairment of the ability to speak, with comparatively intact speech perception. However, some studies have found effects on speech perception under adverse listening conditions, indicating that Broca's area is also involved in speech perception. While these studies have focused on auditory speech perception other studies have shown that Broca's area is activated by visual speech perception. Furthermore, one preliminary report found that a patient with Broca's aphasia did not experience the McGurk illusion suggesting that an intact Broca's area is necessary for audiovisual integration of speech. Here we describe a patient with Broca's aphasia who experienced the McGurk illusion. This indicates that an intact Broca's area is not necessary for audiovisual integration of speech. The McGurk illusions this patient experienced were atypical, which could be due to Broca's area having a more subtle role in audiovisual integration of speech. The McGurk illusions of a control subject with Wernicke's aphasia were, however, also atypical. This indicates that the atypical McGurk illusions were due to deficits in speech processing that are not specific to Broca's aphasia.
Highlights
Broca’s area has long been known to be necessary for speech production as evidenced by the severe impairment to speech production, known as expressive, non-fluent or Broca’s aphasia, caused by lesions to this area located in the ventrolateral prefrontal cortex (Broca, 1861)
The sight of the talking face influenced speech perception significantly in Patient ML with Broca’s aphasia. This was evident as a smaller proportion correct for the incongruent audiovisual stimuli relative to the auditory stimuli
This indicates that ML experienced a McGurk illusion and, that an intact Broca’s area is not required for audiovisual integration of speech
Summary
Broca’s area has long been known to be necessary for speech production as evidenced by the severe impairment to speech production, known as expressive, non-fluent or Broca’s aphasia, caused by lesions to this area located in the ventrolateral prefrontal cortex (Broca, 1861). It has long been known that expressive aphasia can be dissociated from impairment of speech perception known as receptive, fluent or Wernicke’s aphasia (Wernicke, 1874), caused by damage to Wernicke’s area in the posterior superior temporal sulcus (STS). This dissociation may, not be entirely complete as speech perception under adverse conditions can be impeded in Broca’s aphasics (Blumstein et al, 1977; Moineau et al, 2005). As changes in the excitability of motor cortex due to speech perception
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
