title: Plasticity in bilateral superior temporal cortex: Effects of deafness and cochlear implantation on auditory and visual speech processing.
abstract: While many individuals can benefit substantially from cochlear implantation, the ability to perceive and understand auditory speech with a cochlear implant (CI) remains highly variable amongst adult recipients. Importantly, auditory performance with a CI cannot be reliably predicted based solely on routinely obtained information regarding clinical characteristics of the CI candidate. This review argues that central factors, notably cortical function and plasticity, should also be considered as important contributors to the observed individual variability in CI outcome. Superior temporal cortex (STC), including auditory association areas, plays a crucial role in the processing of auditory and visual speech information. The current review considers evidence of cortical plasticity within bilateral STC, and how these effects may explain variability in CI outcome. Furthermore, evidence of audio-visual interactions in temporal and occipital cortices is examined, and relation to CI outcome is discussed. To date, longitudinal examination of changes in cortical function and plasticity over the period of rehabilitation with a CI has been restricted by methodological challenges. The application of functional near-infrared spectroscopy (fNIRS) in studying cortical function in CI users is becoming increasingly recognised as a potential solution to these problems. Here we suggest that fNIRS offers a powerful neuroimaging tool to elucidate the relationship between audio-visual interactions, cortical plasticity during deafness and following cochlear implantation, and individual variability in auditory performance with a CI.
authors.affiliation: National Institute for Health Research (NIHR) Nottingham Hearing Biomedical Research Unit, Ropewalk House, 113 The Ropewalk, Nottingham, NG1 5DU, United Kingdom; Otology and Hearing Group, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, NG7 2UH, United Kingdom. Electronic address: carly.anderson@nottingham.ac.uk.
authors.forename: Carly A
authors.initials: CA
authors.lastname: Anderson
authors.affiliation: Institut Arthur Vernes, ENT Surgery, Paris, 75006, France; Nottingham University Hospitals NHS Trust, Derby Road, Nottingham, NG7 2UH, United Kingdom. Electronic address: dianelazard@yahoo.fr.
authors.forename: Diane S
authors.initials: DS
authors.lastname: Lazard
authors.affiliation: National Institute for Health Research (NIHR) Nottingham Hearing Biomedical Research Unit, Ropewalk House, 113 The Ropewalk, Nottingham, NG1 5DU, United Kingdom; Otology and Hearing Group, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, NG7 2UH, United Kingdom; Nottingham University Hospitals NHS Trust, Derby Road, Nottingham, NG7 2UH, United Kingdom; Medical Research Council (MRC) Institute of Hearing Research, The University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom. Electronic address: douglas.hartley@nottingham.ac.uk.
authors.forename: Douglas E H
authors.initials: DE
authors.lastname: Hartley
mesh_terms: D000161:Acoustic Stimulation; D000222:Adaptation, Physiological; D000223:Adaptation, Psychological; D000818:Animals; D019929:Cochlear Implantation / Q000295:instrumentation*; D003054:Cochlear Implants; D032882:Comprehension; D003463:Cues; D003638:Deafness / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000523:psychology / Q000534:rehabilitation*; D004558:Electric Stimulation; D006309:Hearing; D006801:Humans; D059906:Neuroimaging / Q000379:methods; D009473:Neuronal Plasticity; D019986:Persons with Hearing Disabilities / Q000523:psychology / Q000534:rehabilitation*; D010775:Photic Stimulation; D019265:Spectroscopy, Near-Infrared; D013065:Speech Intelligibility; D013067:Speech Perception; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014796:Visual Perception
keywords: Audio-visual interactions; Cortical plasticity; Functional near-infrared spectroscopy; Occipital cortex; Speechreading; Superior temporal cortex