title: The role of the salience network in processing lexical and nonlexical stimuli in cochlear implant users: an ALE meta-analysis of PET studies.
abstract: Previous positron emission tomography (PET) studies have shown that various cortical areas are activated to process speech signal in cochlear implant (CI) users. Nonetheless, differences in task dimension among studies and low statistical power preclude from understanding sound processing mechanism in CI users. Hence, we performed activation likelihood estimation meta-analysis of PET studies in CI users and normal hearing (NH) controls to compare the two groups. Eight studies (58 CI subjects/92 peak coordinates; 45 NH subjects/40 peak coordinates) were included and analyzed, retrieving areas significantly activated by lexical and nonlexical stimuli. For lexical and nonlexical stimuli, both groups showed activations in the components of the dual-stream model such as bilateral superior temporal gyrus/sulcus, middle temporal gyrus, left posterior inferior frontal gyrus, and left insula. However, CI users displayed additional unique activation patterns by lexical and nonlexical stimuli. That is, for the lexical stimuli, significant activations were observed in areas comprising salience network (SN), also known as the intrinsic alertness network, such as the left dorsal anterior cingulate cortex (dACC), left insula, and right supplementary motor area in the CI user group. Also, for the nonlexical stimuli, CI users activated areas comprising SN such as the right insula and left dACC. Previous episodic observations on lexical stimuli processing using the dual auditory stream in CI users were reconfirmed in this study. However, this study also suggests that dual-stream auditory processing in CI users may need supports from the SN. In other words, CI users need to pay extra attention to cope with degraded auditory signal provided by the implant.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jae-Jin
authors.initials: JJ
authors.lastname: Song
authors.forename: Sven
authors.initials: S
authors.lastname: Vanneste
authors.forename: Diane S
authors.initials: DS
authors.lastname: Lazard
authors.forename: Paul
authors.initials: P
authors.lastname: Van de Heyning
authors.forename: Joo Hyun
authors.initials: JH
authors.lastname: Park
authors.forename: Seung Ha
authors.initials: SH
authors.lastname: Oh
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ridder
mesh_terms: D001307:Auditory Perception / Q000502:physiology*; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001931:Brain Mapping; D003054:Cochlear Implants; D034381:Hearing Loss / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D016013:Likelihood Functions; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000503:physiopathology; D049268:Positron-Emission Tomography
keywords: brain; cochlear implant; meta-analysis; positron emission tomography