Phonological processing of rhyme in spoken language and location in sign language by deaf and hearing participants: A neurophysiological study

Abstract

Sign languages (SL), like oral languages (OL), organize elementary, meaningless units into meaningful semantic units. Our aim was to compare, at behavioral and neurophysiological levels, the processing of the location parameter in French Belgian SL to that of the rhyme in oral French. Ten hearing and 10 profoundly deaf adults performed a rhyme judgment task in OL and a similarity judgment on location in SL. Stimuli were pairs of pictures. As regards OL, deaf subjects' performances, although above chance level, were significantly lower than that of hearing subjects, suggesting that a metaphonological analysis is possible for deaf people but rests on phonological representations that are less precise than in hearing people. As regards SL, deaf subjects scores indicated that a metaphonological judgment may be performed on location. The contingent negative variation (CNV) evoked by the first picture of a pair was similar in hearing subjects in OL and in deaf subjects in OL and SL. However, an N400 evoked by the second picture of the non-rhyming pairs was evidenced only in hearing subjects in OL. The absence of N400 in deaf subjects may be interpreted as the failure to associate two words according to their rhyme in OL or to their location in SL. Although deaf participants can perform metaphonological judgments in OL, they differ from hearing participants both behaviorally and in ERP. Judgment of location in SL is possible for deaf signers, but, contrary to rhyme judgment in hearing participants, does not elicit any N400.