Infants Born with Hearing Loss Show Disruptions in Brain Design
London-UK, November 12, 2025
Pioneering neuroimaging research conducted on infants born with hearing loss has revealed that the absence of auditory input from birth triggers measurable and significant disruptions in the brain’s fundamental architectural design.
The study, which used advanced Magnetic Resonance Imaging (MRI) on babies as young as three days old, found distinct alterations in the functional connectivity between key regions responsible for hearing, vision, and cognitive processing.
This critical finding challenges the long-held assumption that the auditory cortex simply remains dormant without sound, suggesting instead that the brain rapidly reorganises itself in response to sensory deprivation, with implications for the timing and effectiveness of early interventions like cochlear implants and hearing aids.
Key Headlines
Early Reorganisation:
The study provides the earliest evidence yet that sensory deprivation (hearing loss) initiates rapid and subtle reorganisation of neural networks within days of birth.
Connectivity Changes:
Infants with hearing loss showed weakened connectivity within the auditory pathways and, more surprisingly, heightened connectivity between visual processing regions and the auditory cortex.
Sensitive Window:
The research highlights a crucial and very sensitive developmental window in the first few months of life where the brain is most plastic and receptive to normalisation through interventions.
Optimal Timing:
The findings strongly support the push for universal newborn hearing screening and intervention within the first three to six months of life to limit the extent of cross-modal reorganisation.
The study, a collaborative effort between researchers at King’s College London and the University of Iowa, utilised quiet, highly sensitive functional MRI (fMRI) to map the brain activity of newborns.
Functional connectivity analysis measures how different regions of the brain communicate with each other—the “design” of the brain’s internal network.
In infants with typical hearing, the study confirmed a robust and independent network connecting the ears to the auditory cortex in the temporal lobe.
However, in the cohort of babies diagnosed with severe-to-profound hearing loss, the researchers found a distinct pattern of dysconnectivity. The primary auditory pathways, which rely on incoming sound to establish their connections, showed weaker, less integrated functional links.
More striking and novel was the discovery of cross-modal plasticity. The researchers observed that in the hearing-impaired infants, areas of the brain typically reserved for processing sound were being co-opted or re-wired to communicate more robustly with the visual cortex and other sensory processing centres.
This phenomenon, where one sense invades the territory of a deprived sense, is known as cross-modal reorganisation. While this process is known to happen in older children and adults who have been deaf for many years, observing it in newborns within days of birth indicates that the brain’s attempt to adapt is much more immediate and aggressive than previously understood.
The fact that the brain begins to restructure itself almost immediately after birth carries profound implications for clinical practice. The existing standard for hearing intervention often recommends fitting hearing aids or performing cochlear implant surgery by six months of age.
The new data suggests that by waiting that long, the brain has already initiated a significant rewiring process. When sound is finally introduced via an implant, the auditory cortex is no longer a blank slate ready to process sound; it has already been partially recruited to assist with other sensory tasks, such as vision.
This competitive reorganisation may partially explain why children who receive cochlear implants later often have less successful outcomes in developing spoken language compared to those implanted very early. The visual system, having taken over some of the auditory processing space, may compete with the sound information when it finally arrives, making it harder for the child to effectively map sounds to language.
The findings provide compelling neurobiological evidence to reinforce the ethical and clinical argument for the earliest possible intervention.
The sensitive developmental window for establishing normal auditory pathways is narrower than previously thought, making the successful implementation of universal newborn hearing screening and immediate referral for therapeutic action a critical public health priority.
By providing sound input as quickly as possible, clinicians can take advantage of the brain’s incredible plasticity to establish the correct neural architecture before the maladaptive, cross-modal design changes become entrenched.
