Does a lesion in Broca's area cause apraxia?

Abstract

Background and Aim: Broca's area, which comprises the inferior frontal gyrus and its surrounding regions, is associated with language function. Recent functional imaging studies showed that it is also related to processing goal-directed actions.This study aimed to determine the types of action disorders that occur after damage to Broca's area. Methods: Here, we report four patients with left inferior frontal lesions that included Broca's area. The patients did not exhibit severe language comprehension impairment or paralysis that affected the apraxia testing. The patients were asked to perform intransitive gestures in response to verbal commands, imitate intransitive gestures, perform transitive gestures in response to verbal commands, perform transitive gestures in response to visual objects, imitate transitive gestures, and use tools. Results: All patients exhibited impaired gestures in response to verbal commands, while the performances regarding imitation and actual tool use were better. An error pattern analysis showed that the patients predominantly made spatial action errors. This pattern corresponds to the classical definitions of ideomotor apraxia. Conclusion: These results indicate that Broca's area mediates action production and that a lesion in this area can cause ideomotor apraxia. Although we should be cautious about the influence of aphasia, we believe that the comprehension deficit observed in our patients cannot account for their apraxic syndromes. Because the deficit was seen mainly for verbal commands, damage in Broca's area may have disrupted the association between verbal and action domains. © 2013 Japanese Society of Neurology and Wiley Publishing Asia Pty Ltd.