Blind people rely much more on voice cues than sighted people for person identification.
Event-related potential (ERP) and brainimaging results have suggested that voice recognition and auditory language processing involve more posterior possibly visual brain regions in the congenitally blind compared to sighted individuals.
To test whether these plastic changes in voice processing can still evolve in adulthood, we investigated a group of late-onset blind people.
In a priming paradigm two successive voices (S1 and S2) were presented. S1 and S2 belonged either to the same or to a different person. Participants made an old-young decision on the S2.
Reaction times were shorter in person-congruent trials than in person-incongruent trials for both, the late-onset blind group and for the sighted controls.
ERPs related to the person-incongruent S2 stimuli were characterized by an enhanced negativity in early (around 250 ms) and later time epochs (330 - 380 ms). While these effects reached their maximum at central and parietal electrode clusters in the sighted, the maximal amplitude of this effect was found over the occipital and parietal scalp for late-onset blind individuals.
These results provide evidence for adult plasticity of processes related to voice recognition.