Characterizing the area of significant brain activation region to spectrally-degraded music: A functional near-infrared spectroscopy study

Cochlear implants (CIs) are the only auditory prosthesis for treating deafness, yet the ability of implanted patients to music perception is inferior. The present work studied the effect of spectrally-degraded processing (via a noise-vocoding process to simulate CI speech processing) on the area of significant activation in music processing in auditory cortex using functional near-infrared spectroscopy (fNIRS). The music stimulus was processed by 32-channel and 16-channel noise-vocoders, and presented to normal-hearing listeners to perceive. The fNIRS-based results in this work showed that compared with the original music condition, spectrally-degraded processing with a large number (i.e., 32) of vocoded channels had a significant influence on the area of significant activation in the left auditory hemisphere, and further decreasing the number of vocoded channels remarkably reduced the area of significant activation in the right auditory hemisphere.