Prominent reflexive eye-movement orienting associated with deafness

Abstract

Profound deafness affects orienting of visual attention. Until now, research focused exclusively on covert attentional orienting, neglecting whether overt oculomotor behavior may also change in deaf people. Here we used the pro- and anti-saccade task to examine the relative contribution of reflexive and voluntary eye-movement control in profoundly deaf and hearing individuals. We observed a behavioral facilitation in reflexive compared to voluntary eye movements, indexed by faster saccade latencies and smaller error rates in pro- than anti-saccade trials, which was substantially larger in deaf than hearing participants. This provides the first evidence of plastic changes related to deafness in overt oculomotor behavior, and constitutes an ecologically relevant parallel to the modulations attributed to deafness in covert attention orienting. Our findings also have implications for designers of real and virtual environments for deaf people and reveal that experiments on deaf visual abilities must not ignore the prominent reflexive eye-movement orienting in this sensory-deprived population.

Keywords:

• Deafness
• Eye movements
• Cortical plasticity

Acknowledgments

We wish to thank the Ente Nazionale Sordi (Trento) and Associazione Sordi Trenti for participation in the study. We are grateful to Prof. Massimo Turatto for initial discussion on the paradigm. This work was supported by a PRIN 2008 grant from MIUR (Italy) to F.P. This work has also been supported by the Provincia autonoma di Trento and the Fondazione Cassa di Risparmio di Trento e Rovereto.