Facilitation of inferior frontal cortex by tDCS induces perceptual learning of severely degraded speech

Introduction: Cochlear implants (CI) offer the possibility to reinstate audition in patients with severe hearing disorders. Due to the limited spectral and temporal resolution of the signal, the auditory input provided by CI is degraded and the ability to adapt to it, thus to reacquire speech comprehension is highly variable and often insufficient. Neurocognitive adaptation to the devices is afforded by perceptual learning. This process can be simulated in healthy individuals by artificially degradation of speech (noise-band vocoding) to test how efficient categorical perceptual sensitivity is generalized, a fea…