Abstract
Background: Words and faces are both subjects of highly expert perceptual processing, but there is a left hemisphere dominance for reading and a right one for face perception. Nevertheless, both have some bilateral representation, raising the question of whether there is some mild word processing impairment in patients with prosopagnosia. Objective: We examined whether patients with prosopagnosia from right hemisphere or bilateral lesions were also impaired in text style discrimination, or word perception. Markers used were delayed word matching and an exaggerated word-length effect, where reading time is proportional to the number of letters in a word. Method: 9 prosopagnosic subjects participated. In the first experiment, subjects sorted handwritten and typed words by either their meaning or their style (i.e. handwriting or font), with the time taken and accuracy measured. In the second experiment we measured the word-length effect for reading single words of 3 to 9 letters, matched for linguistic frequency. The time to onset of verbal naming response was recorded. Results: In experiment 1, no subject demonstrated delayed or inaccurate sorting of words by their identity. Of 4 subjects with only right hemisphere lesions, 3 were impaired in matching for style matching, as were all of the 5 subjects with bilateral lesions. In experiment 2, no subjects with right hemisphere lesions alone showed an exaggerated word-length effect, while all but one of those who had additional left sided damage did. Conclusion: These findings provide further evidence that right hemisphere lesions impair processing of stylistic properties of text. Reductions in the efficiency of word processing appear to require additional left sided lesions in prosopagnosic patients.
Meeting abstract presented at VSS 2014