EEG correlates of auditory rise time processing: A systematic review.

Rise time (RT) is a critical acoustic feature of speech, implicated in typical and atypical language development. While a substantial amount of data has been accumulated on the neurophysiological evidence of RT processing across different conditions and groups of people, these data have not been systematized. This systematic review, conducted according to the PRISMA guidelines across PubMed, Web of Science and APA PsychInfo databases, focuses on studies that have investigated electroencephalographic (EEG) markers of RT sensitivity in humans. A total of 37 studies were identified that manipulated RT and examined different components of event-related potentials (ERPs), brainstem responses, and cortical rhythmic activity. The core finding is consistent across studies: RT prolongation reduces the amplitudes of brain responses and increases their latencies. However, the sensitivity of the EEG markers varied along the auditory hierarchy with the earliest components tracking subtle differences (a few tens of microseconds), while the later components coding the larger changes (up to 500 ms). Effects are further modulated by the experimental parameters, participant age, and speech-related problems, while limited pediatric research, considerable methodological heterogeneity and predominantly small sample sizes limit the clear conclusions on these modulations. Future research should prioritize understudied clinical populations and developmental ERP components such as P1 and N2, which are dominant in children.