A new study published in PLOS Biology reveals that long-term musical training may reduce age-related overactivation of brain networks involved in understanding speech in noisy environments. The findings provide compelling evidence that cognitive reserve, built through sustained musical engagement, can help older adults process speech more efficiently, mimicking the neural patterns of younger adults.
Researchers led by Lei Zhang and colleagues used functional magnetic resonance imaging (fMRI) to explore how aging and musical training impact speech-in-noise (SIN) perception. They compared three groups: older musicians (OMs), older non-musicians (ONMs), and younger non-musicians (YNMs), tasking them with identifying syllables in varying levels of background noise.
The study drew on two competing hypotheses. The “Bolster Compensation Hypothesis” posited that cognitive reserve strengthens age-related neural upregulation during tasks, increasing brain activity. The “Hold-Back Upregulation Hypothesis,” alternatively, suggested that higher cognitive reserve may prevent excessive neural recruitment, maintaining more youthful-like brain activity patterns.
Behaviorally, OMs outperformed ONMs across moderate signal-to-noise ratios, though both groups underperformed compared to younger controls. Crucially, fMRI analyses revealed that ONMs exhibited heightened task-induced functional connectivity (TiFC) in the auditory dorsal stream, comprising regions like the posterior superior temporal gyrus (pSTG), supramarginal gyrus (SMG), and supplementary motor area (SMA), compared to OMs and YNMs. In contrast, OMs demonstrated more balanced neural activity, resembling that of YNMs.
These results align with the Hold-Back Upregulation Hypothesis: musical training appears to promote neural efficiency, allowing older adults to process challenging auditory stimuli without excessive brain compensation. Musicians also displayed more youth-like spatial patterns of brain connectivity, reinforcing the concept of cognitive reserve through life-long skill development.
This work supports broader cognitive aging theories, such as the Scaffolding Theory of Aging and Cognition, which suggests that enriching life experiences like musical practice enhance neural resilience. As acoustic communication becomes increasingly demanding with age, musical training might serve as a valuable intervention to sustain listening abilities and cognitive health in older populations.
