Obligatory Broca's area modulation associated with passive speech perception.

Broca's area is crucial for speech production. Several recent studies have suggested that it has an additional role in visual speech perception. This conclusion remains tenuous, as earlier studies used tasks requiring active processing of visual speech movements, which may have elicited conscious subvocalizations. To study whether Broca's area is modulated during passive viewing of speech movements, we conducted a functional MRI experiment where participants detected rare and brief visual targets that were briefly superimposed on two task irrelevant conditions: passive viewing of silent speech versus nonspeech (gurning) facial movements. Comparison revealed Broca's area to be more active when observing speech. These findings provide further support for Broca's area in speech perception and have clear implications for rehabilitation of aphasia.

Treating visual speech perception to improve speech production in nonfluent aphasia.

BACKGROUND AND PURPOSE: Several recent studies have revealed modulation of the left frontal lobe speech areas not only during speech production but also for speech perception. Crucially, the frontal lobe areas highlighted in these studies are the same ones that are involved in nonfluent aphasia. Based on these findings, this study examined the utility of targeting visual speech perception to improve speech production in nonfluent aphasia. METHODS: Ten patients with chronic nonfluent aphasia underwent computerized language treatment utilizing picture-word matching. To examine the effect of visual speech perception on picture naming, 2 treatment phases were compared-one that included matching pictures to heard words and another in which pictures were matched to heard words accompanied by a video of the speaker's mouth presented on the computer screen. RESULTS: The results revealed significantly improved picture naming of both trained and untrained items after treatment when it included a visual speech component (ie, seeing the speaker's mouth). In contrast, the treatment phase in which pictures were only matched to heard words did not result in statistically significant improvement of picture naming. CONCLUSIONS: The findings suggest that focusing on visual speech perception can significantly improve speech production in nonfluent aphasia and may provide an alternative approach to treat a disorder in which speech production seldom improves much in the chronic phase of stroke.