Fundamental frequency predominantly drives talker differences in auditory brainstem responses to continuous speech

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Speech Processing

Background:

• Deriving human neural responses to natural speech is feasible.
• Differences in neural responses to male- and female-uttered speech exist.
• Talker variability can complicate speech communication research.

Purpose of the Study:

• To investigate if fundamental frequency (F0) equalization reduces neural response differences between male and female speech.
• To examine the relationship between F0 and auditory brainstem responses (ABRs) to speech.
• To compare speech ABRs with click ABRs and assess the role of acoustic processing.

Main Methods:

• Recorded auditory brainstem responses (ABRs) to natural speech from male and female talkers.
• Manipulated speech stimuli to equalize fundamental frequency (F0) between talkers.
• Recorded click ABRs at varying stimulus rates.
• Utilized computational modeling to predict ABRs based on peripheral and brainstem processing.

Main Results:

• Matched F0 in male and female speech resulted in highly similar ABRs.
• Increasing F0 in speech and stimulus rates in click trains led to smaller and later ABRs.
• Modeled responses indicated peripheral and brainstem acoustic processing predicted observed ABR differences.

Conclusions:

• Fundamental frequency is a key acoustic factor influencing neural speech encoding.
• Auditory brainstem responses to speech are sensitive to acoustic properties like F0.
• Peripheral and brainstem mechanisms adequately explain variations in neural responses to speech and non-speech stimuli.