[PS-2.1] Face processing in congenitally deaf signers

Bednaya, E. 2 , Bottari, D. 1, 2 , Dormal, G. 1 , Villwock, A. 1, 3 , Dzhelyova, M. 4 , Grin, K. 1 , Pietrini, P. 2 , Ricciardi, E. 2 , Rossion, B. 4, 5 & Röder, B. 1

1 Biological Psychology and Neuropsychology, University of Hamburg, Hamburg, Germany
2 Molecular Mind Lab, IMT School for Advanced Studies Lucca, Lucca, Italy
3 Department of Linguistics, University of California San Diego, La Jolla, CA, USA
4 Psychological Sciences Research Institute, IONS, Université catholique de Louvain, Louvain-la-Neuve, Belgium
5 Université de Lorraine, CNRS, CRAN, Nancy, France

Studies on face processing in congenitally deaf signers have revealed alterations at both the behavioural and neural levels. Nevertheless, a systematic assessment of different aspects of face processing in this population is lacking. We tested fourteen congenitally deaf signers and fourteen matched hearing controls using fast periodic visual stimulation paradigms combined with EEG recording. Three levels of face processing were assessed: 1) face categorization (faces within a sequence of objects); 2) individual face discrimination (different vs. identical unfamiliar faces) and 3) emotional facial expression discrimination (expressive vs. neutral faces). In each experiment, stimuli were presented at a frequency of 6 Hz. Within each sequence, oddball stimuli were introduced at fixed intervals of one every 5 stimuli, resulting in an oddball frequency of 1.2 Hz (6Hz/5). Results were twofold. In Experiments 1 and 3, hearing subjects showed right-lateralized responses, whereas deaf signers displayed a left lateralized hemispheric dominance of the response. In Experiment 2, the deaf signers showed a larger amplitude at frontal and central electrodes as compared to hearing participants, possibly suggesting a cross-modal activation of auditory cortices. Our results reveal that congenitally deaf signers exhibit distinct changes for different aspects of face processing.