An fMRI study on forensic phonetic speaker recognition with blind and sighted listeners

A forensic phonetic speaker recognition experiment with spontaneous speech samples of known and unknown speakers was carried out while listeners underwent a functional magnetic resonance imaging (fMRI) scan. In sighted participants, listening to familiar in contrast to unfamiliar speakers elicited brain activations in the right frontal pole and the left part of the cerebellum. When fMRI data of the first and the second 15 seconds of listening to familiar speakers were compared, it was found that auditory areas were significantly stronger activated in the first part and visual areas showed stronger activations in the second part. In two blind participants, there were no brain activations which were stronger in the first compared to the second 15 seconds of listening to familiar speakers’ voice samples. When the second part was compared to the first, also blind listeners showed stronger activations in visual areas.