Objective neural indices of speech-in-noise perception.

Numerous factors contribute to understanding speech in noisy listening environments. There is a clinical need for objective biological assessment of auditory factors that contribute to the ability to hear speech in noise, factors that are free from the demands of attention and memory. Subcortical processing of complex sounds such as speech (auditory brainstem responses to speech and other complex stimuli [cABRs]) reflects the integrity of auditory function. Because cABRs physically resemble the evoking acoustic stimulus, they can provide objective indices of the neural transcription of specific acoustic elements (e.g., temporal, spectral) important for hearing speech. As with brainstem responses to clicks and tones, cABRs are clinically viable in individual subjects. Subcortical transcription of complex sounds is also clinically viable because of its known experience-dependence and role in auditory learning. Together with other clinical measures, cABRs can inform the underlying biological nature of listening and language disorders, inform treatment strategies, and provide an objective index of therapeutic outcomes. In this article, the authors review recent studies demonstrating the role of subcortical speech encoding in successful speech-in-noise perception.