Speechreading: advances in understanding its cortical bases and implications for deafness and speech rehabilitation

Some cortical correlates of (silent) speechreading in normal people are described and contextualized with respect both to seeing faces and to hearing speech. Some preliminary work with two people with abnormal language is described, as are some findings concerning evoked responses to seen speech. Superior temporal cortical areas (classical 'speech association' areas) are strongly and specifically implicated in seeing silent speech. In addition, primary auditory cortex can be activated by silent speechreading in hearing people. The implications of these findings for deafness and for issues of compensation and plasticity are outlined.