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.
• Observed differences in neural responses to male- and female-uttered speech can complicate research.
• Talker variability may limit realistic communication scenario studies.

Purpose of the Study:

• To investigate if fundamental frequency equalization reduces neural response differences between male and female talkers.
• To examine the impact of fundamental frequency on 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 fundamental frequency (pitch) to match male and female voices.
• Administered click auditory brainstem response (ABR) tests at varying stimulus rates.
• Utilized computational models to predict neural responses based on acoustic properties.

Main Results:

• Auditory brainstem responses (ABRs) were highly similar between male and female talkers when their fundamental frequencies were matched.
• Increasing fundamental frequency led to smaller and delayed ABRs.
• Click ABRs showed similar decreases in amplitude and latency with increasing stimulus rates.
• Modeled responses indicated that peripheral and brainstem processing of acoustics explained observed ABR patterns.

Conclusions:

• Fundamental frequency equalization effectively minimizes neural response differences attributed to talker sex.
• Auditory brainstem responses (ABRs) are sensitive to fundamental frequency variations in speech.
• Acoustic processing in the peripheral and brainstem auditory system adequately predicts speech and click ABR characteristics.