title: Cortical reorganization in postlingually deaf cochlear implant users: Intra-modal and cross-modal considerations.
abstract: With the advances of cochlear implant (CI) technology, many deaf individuals can partially regain their hearing ability. However, there is a large variation in the level of recovery. Cortical changes induced by hearing deprivation and restoration with CIs have been thought to contribute to this variation. The current review aims to identify these cortical changes in postlingually deaf CI users and discusses their maladaptive or adaptive relationship to the CI outcome. Overall, intra-modal and cross-modal reorganization patterns have been identified in postlingually deaf CI users in visual and in auditory cortex. Even though cross-modal activation in auditory cortex is considered as maladaptive for speech recovery in CI users, a similar activation relates positively to lip reading skills. Furthermore, cross-modal activation of the visual cortex seems to be adaptive for speech recognition. Currently available evidence points to an involvement of further brain areas and suggests that a focus on the reversal of visual take-over of the auditory cortex may be too limited. Future investigations should consider expanded cortical as well as multi-sensory processing and capture different hierarchical processing steps. Furthermore, prospective longitudinal designs are needed to track the dynamics of cortical plasticity that takes place before and after implantation.
authors.affiliation: Neuropsychology Lab, Department of Psychology, European Medical School, Carl von Ossietzky University Oldenburg, Germany. Electronic address: maren.stropahl@uni-oldenburg.de.
authors.forename: Maren
authors.initials: M
authors.lastname: Stropahl
authors.affiliation: Neuropsychology Lab, Department of Psychology, European Medical School, Carl von Ossietzky University Oldenburg, Germany; Cluster of Excellence Hearing4all Oldenburg, Germany.
authors.forename: Ling-Chia
authors.initials: LC
authors.lastname: Chen
authors.affiliation: Neuropsychology Lab, Department of Psychology, European Medical School, Carl von Ossietzky University Oldenburg, Germany; Cluster of Excellence Hearing4all Oldenburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Debener
mesh_terms: D000222:Adaptation, Physiological; D000223:Adaptation, Psychological; D001303:Auditory Cortex / Q000503:physiopathology*; D001306:Auditory Pathways / Q000503:physiopathology; D019929:Cochlear Implantation / Q000295:instrumentation*; D003054:Cochlear Implants; D003638:Deafness / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology / Q000534:rehabilitation*; D006309:Hearing; D006801:Humans; D009473:Neuronal Plasticity; D019986:Persons with Hearing Disabilities / Q000523:psychology / Q000534:rehabilitation*; D021641:Recognition, Psychology; D020127:Recovery of Function; D013065:Speech Intelligibility; D013067:Speech Perception
keywords: Auditory deprivation; Brain plasticity; Cochlear implant (CI); Cross-modal reorganization; Intra-modal reorganization; Postlingual deafness