Time-efficient measures of auditory frequency selectivity

Abstract

Objective: The objective of this study was to compare two recently proposed methods for fast measurements of psychophysical tuning curves (fast-PTCs) in terms of resulting tuning curve features and training effects. Design: Fast-PTCs with swept-noise (SN) and gated-noise (GN) maskers were measured at signal frequencies of 500, 1000, 2000, and 4000 Hz. The effect of amplitude modulating the signal in the GN condition was evaluated. Two PTC runs were obtained for each condition to assess training effects. Study sample: Eight normally-hearing young adults participated in the study. Results: The SN and GN methods resulted in similar estimates of frequency selectivity when training effects were considered. Amplitude modulating the tone in the GN method reduced the effect of training. On average, SN-PTCs were most repeatable compared to the two other methods and they were not affected by training. Estimation of the shift in the PTC tip frequency was not affected by the measurement method or training effects. Fast-PTC methods resulted in similar estimates of tuning as compared to published notched-noise data. Conclusions: The SN method and the GN procedure with amplitude modulated signals allowed for time-efficient estimation of frequency selectivity that was unaffected by training.

Key Words::

• Psychophysical tuning curves
• Frequency selectivity
• Equivalent rectangular bandwidth
• Normally-hearing

Acknowledgements

This work was supported by NIDCD grant DC006014 and Northwestern University. We thank Dr. Aleksander Sęk for providing the swept-noise fast-PTC software and for help with implementing the method in our laboratory. We thank Dr. Sumitrajit Dhar, Dr. Beverly Wright, and Dr. Steven Zecker for fruitful discussions, and Kathleen Dunckley for reading the manuscript. We are also grateful to Dr. Andrew Oxenham and Dr. Christopher Shera for sharing their data. Preliminary data from this study were presented at the 34th Mid-Winter Meeting of the Association for Research in Otolaryngology in Baltimore, Maryland, USA, February 2011.

Declaration of interest: The authors report no declarations of interest.

Notes

1. For any filter, the ERB corresponds to the bandwidth of the rectangular filter that has the same center frequency and passes the same total power.

2. LOESS smoothing was utilized instead of a two-point running average (e.g. Sęk et al, 2005), because the former strategy resulted in more regular curves than the latter one without compromising the overall shape.