Crossed Wires is now live on OSF â an open-access white paper exploring the overlooked impact of hemispheric lateralisation in cochlear implantation for APD and early-onset deafness. đ https://osf.io/pwqr7/
Abstract Cochlear implantation is often approached as a peripheral correction of hearing loss, with ear selection guided primarily by audiological severity, device history, or anatomical constraints. Yet for individuals with prelingual deafness and auditory processing disorder (APD)âparticularly those who developed language through visual-dominant modalities such as lipreading and captioningâthis approach may overlook a crucial factor: brain lateralisation.
The auditory system is inherently asymmetrical, with each ear routing input to the opposite cerebral hemisphere. Given that the left hemisphere is typically dominant for language decoding, implanting the left ear (feeding into the right hemisphere) may, in some cases, introduce an artificial signal into a neural system ill-suited to interpret it.
This paper proposes that ear choice in cochlear implantation should consider cerebral dominance and sensory compensation history, particularly in older CI recipients with entrenched APD and visual adaptation. Drawing on findings from research on hemispheric language dominance, cortical reorganisation, unilateral vs bilateral stimulation, and cross-modal plasticity, it identifies a critical gap: current CI evaluation protocols rarely account for how early sensory deprivation and neural re-routing shape long-term comprehension.
Evidence suggests CI outcomes can vary based on implantation side (Chilosi et al., 2014) and that unilateral implants may lead to asymmetric cortical dominance with lasting consequences (Gordon et al., 2013).
This paper doesnât prescribe a universal protocol, but calls for a more personalised, neurocognitive frameworkâone that recognises that more input does not always mean more understanding, especially when the signal enters the wrong side of a rewired brain.
