Increased activity in frontal motor cortex compensates impaired speech perception in older adults


Understanding speech in noisy environments is challenging, especially for seniors. Although$backslash$r$backslash$nevidence suggests that older adults increasingly recruit prefrontal cortices to offset reduced$backslash$r$backslash$nperiphery and central auditory processing, the brain mechanisms underlying such$backslash$r$backslash$ncompensation remain elusive. Here we show that relative to young adults, older adults show$backslash$r$backslash$nhigher activation of frontal speech motor areas as measured by functional MRI during a$backslash$r$backslash$nsyllable identification task at varying signal-to-noise ratios. This increased activity correlates$backslash$r$backslash$nwith improved speech discrimination performance in older adults. Multivoxel pattern$backslash$r$backslash$nclassification reveals that despite an overall phoneme dedifferentiation, older adults show$backslash$r$backslash$ngreater specificity of phoneme representations in frontal articulatory regions than auditory$backslash$r$backslash$nregions. Moreover, older adults with stronger frontal activity have higher phoneme specificity$backslash$r$backslash$nin frontal and auditory regions. Thus, preserved phoneme specificity and upregulation of$backslash$r$backslash$nactivity in speech motor regions provide a means of compensation in older adults for$backslash$r$backslash$ndecoding impoverished speech representations in adverse listening conditions.

Nature Communications