A case of impaired verbalization but preserved gesticulation of motion events

In most cultures, most of the time, when people talk they gesture. We took advantage of a rare opportunity to explore the relation between the verbalization and gesticulation of motion events by studying Marcel, an English speaker with a unilateral left-hemisphere lesion affecting frontal, parietal, and temporal sectors of the perisylvian cortex. Marcel has intact semantic knowledge of the three major classes of words that are commonly used in English descriptions of motion events - specifically, concrete nouns, action verbs, and spatial prepositions - as well as intact syntactic knowledge of how these word classes are typically combined in the intransitive motion construction (e.g., The ball rolled down the hill). However, his ability to retrieve the lexical-phonological structures of these words is severely impaired. Despite this profound anomia, he is still remarkably skilled at producing iconic manual depictions of motion events, as demonstrated in two experiments involving spontaneous gestures and one experiment involving elicited gestures. Moreover, the structural characteristics of Marcel's gestures are clearly sensitive to the idiosyncratic meanings of English verbs and prepositions, and they may also be sensitive to the way motion events are syntactically packaged in the intransitive motion construction. These findings improve our understanding of how some brain-damaged individuals with severe aphasia but without manual apraxia can successfully employ gesture to augment the semantic content of their speech.