Audiovisual Integration and Rehabilitation Training in Deafness and Cochlear Implantation. A Systematic Review of Speechreading and Multisensory Recovery

Abstract

Speech is heard and seen at the same time. The face carries cues that help a listener understand a talker. When hearing is reduced the value of these visual cues rises. This review gathers the evidence on audiovisual integration and on speechreading and on training in deaf people and in cochlear implant users.The aim was to synthesize studies on how vision supports speech and on how structured training can strengthen this support across the course of deafness and recovery after implantation.A systematic search framework was applied across major databases. Records were screened against defined criteria. Thirty studies formed the final corpus. Data were extracted on population and method and outcome and were synthesized through a thematic approach.The corpus ranged from classic behavioral work to modern neuroimaging. Five themes emerged. These were audiovisual speech integration and speechreading and visual speech and rehabilitation and multisensory training and cross modal plasticity and degraded speech in clinical groups. Implant users emerged as strong integrators of sound and vision and training improved performance.Vision is central to speech understanding in deafness and after cochlear implantation. Training that pairs sound and vision can build on this natural integration and it deserves a place in rehabilitation planning.