Predicting Spectro-Temporal Modulation Detection Thresholds With a Functional Auditory Model

Area of Science:

• Auditory Neuroscience
• Speech Perception
• Psychoacoustics

Background:

• Spectro-temporal modulation (STM) sensitivity is crucial for speech intelligibility in noise.
• Underlying auditory mechanisms for STM detection are not fully understood.
• STM sensitivity may serve as a marker for auditory processing deficits.

Purpose of the Study:

• To measure STM detection thresholds in young normal-hearing and older hearing-impaired listeners.
• To evaluate the predictive power of the Computational Auditory Signal Processing and Perception (CASP) model for individual STM performance.
• To investigate the contribution of peripheral auditory system damage to STM deficits.

Main Methods:

• STM detection thresholds were measured across six conditions varying spectral (0, 1, 2 c/o) and temporal (4, 12 Hz) rates.
• The CASP model was individualized using audiometric and Adaptive Categorical Loudness Scaling (ACALOS) data to estimate hair cell loss.
• Group comparisons were made between young normal-hearing and older hearing-impaired listeners.

Main Results:

• Older hearing-impaired listeners exhibited significantly elevated STM thresholds compared to young normal-hearing listeners, especially at higher spectral rates.
• The CASP model simulations replicated general threshold patterns but underestimated group differences and interindividual variability.
• Model sensitivity to estimated hair cell loss was limited, suggesting the involvement of supra-threshold processing.

Conclusions:

• STM deficits are prevalent in older hearing-impaired individuals and affect speech intelligibility.
• Current auditory models like CASP show potential but require enhancements in peripheral and central processing representations to accurately predict individual STM performance.
• Supra-threshold mechanisms play a significant role in STM detection deficits beyond peripheral damage.