Rewiring the Listening Brain: The Neuroscience of Auditory-Cognitive Plasticity

The human brain possesses an incredible, lifelong ability to change and reorganise its connections, a property known as neuroplasticity. While this concept is often applied to motor skills or memory, its application to hearing is revolutionary.

For decades, hearing loss was viewed as a passive, permanent sensory deficit. Now, advanced neuroscience confirms that through Auditory-Cognitive Training (ACT), the central auditory system can be actively optimised, leading to measurable improvements in listening skills, especially in complex environments.

This shift in understanding, from treating a damaged ear to training a malleable brain, is the scientific foundation of eargym.

The Central Auditory System: Where Hearing Happens

When a sound enters the ear, it is rapidly converted into electrical signals that travel up the auditory pathway. While the cochlea acts as the initial sensor, the true work of hearing (separating speech from noise, assigning meaning, and focusing attention) occurs in the brain’s cortical and subcortical structures.

Research has successfully tracked the neural changes that occur in these structures following structured auditory training. Using objective measures like Auditory Evoked Potentials (AEPs), studies show that training directly impacts the efficiency of the brain's encoding process:

• Cortical changes: Following training, some studies have reported changes in cortical AEPs, such as an increased amplitude of waves like the N1-P2 complex, and a decreased latency of these responses (1). These findings suggest that the brain requires less time and effort to process incoming sound after training.

• Subcortical changes: Training has also been shown to enhance the subcortical encoding of crucial cues for speech-in-noise perception, such as pitch-related cues (like the fundamental frequency) (2). This strengthening of the initial neural signal sets the stage for clearer processing higher up the pathway.

Enhanced Speech-in-Noise Perception

The ultimate goal of Auditory-Cognitive Training (ACT) is to improve Speech-in-Noise (SiN) perception, which is the functional ability that most impacts daily communication. Research has repeatedly demonstrated a direct, causal link between structured ACT and significant, lasting improvements in SiN performance.

A review of evidence for neural plasticity in adults confirmed that training-related improvements in SiN perception accompany neural changes in auditory processing (3). Specifically, training using methods that mimic real-world listening challenges, incorporate feedback, and activate higher-level cognitive skills (like working memory) are highly effective (2).

One study involving personalised auditory-cognitive training for cochlear implant patients, a population highly dependent on brain plasticity for success, found a significant improvement in their ability to understand speech in noise, highlighting the potent effect of focused training (4).

Auditory-Cognitive Training as a Brain Workout

The power of eargym's approach lies in combining auditory and cognitive challenges. This dual approach leverages two known mechanisms of plasticity:

1. Perceptual Learning

This involves the brain adapting to the specific acoustic features of sound, such as separating complex speech signals from competing maskers. This is the bottom-up sensory processing aspect of training.

2. Cognitive Resource Allocation

This is the top-down aspect. Training in a noisy environment forces the brain to enhance selective attention and working memory. So when an individual improves on SiN tasks, they are not just hearing better; they are listening smarter.

A randomized controlled trial (RCT) involving healthy older adults found that Auditory-Cognitive (AC) training significantly improved both auditory and cognitive measures, and crucially, led to changes in brain structure Specifically, the AC training group showed changes in regional gray matter volume (rGMV) in the right dorsolateral prefrontal cortex (a region tied to executive function) and increased functional connectivity in the left temporal pole (a region involved in integrating sound and memory) (5).

This finding is paramount: ACT is not just a skill practice; it is a mechanism for inducing beneficial structural and functional neural plasticity.

Validating and Scaling Auditory Rehabilitation

The scientific consensus is clear: the adult central auditory system is malleable through older adulthood (3). The evidence from electrophysiology and neuroimaging confirms that properly designed auditory training results in:

• Behavioural Gains: Measurable improvement in SiN performance.

• Neural Plasticity: Objective changes in the brain's structure and function.

The next challenge is standardising and delivering this intervention at scale. eargym provides the platform for delivering evidence-based ACT and, equally important, the medical-grade SiN test to objectively measure the resulting neuroplastic change in large patient populations and clinical trials.

The training itself is the intervention, and the measurement of SiN performance is the metric that confirms the brain has been successfully rewired.

References

1. Carcagno, S., & Plack, C. (2011). Subcortical plasticity following perceptual learning in a pitch discrimination task. Journal of the Association for Research in Otolaryngology, 12(1), 89–100. $10.1007/s10162-010-0245-1$

2. Anderson, S., White-Schwoch, T., & Kraus, N. (2013). Training to improve hearing speech in noise: biological mechanisms. Frontiers in Psychology, 4(568). $10.3389/fpsyg.2013.00568$

3. Anderson, S., & Kraus, N. (2013). Auditory Training: Evidence for Neural Plasticity in Older Adults. Perspectives on Hearing and Hearing Disorders: Research and Diagnostics, 17(1), 37–57. $10.1044/hhd17.1.37$

4. Mondel, S., Riss, D., & Honeder, M. (2025). Evaluation of a personalized auditory-cognitive training on the improvement of speech understanding in noise in cochlear implanted patients. European Archives of Oto-Rhino-Laryngology. $10.1007/s00405-024-08579-2$

5. Kawata, N. Y. S., Nouchi, R., Oba, K., Matsuzaki, Y., & Kawashima, R. (2022). Auditory Cognitive Training Improves Brain Plasticity in Healthy Older Adults: Evidence From a Randomized Controlled Trial. Frontiers in Aging Neuroscience, 14, 826672. $10.3389/fnagi.2022.826672$