Psychophysical Tuning Curves as a Correlate of Electrode Position in Cochlear Implant Listeners

  • Lindsay DeVriesEmail author
  • Julie G. Arenberg
Research Article


Speech understanding abilities vary widely among cochlear implant (CI) listeners. A potential source of this variability is the electrode-neuron interface (ENI), which includes peripheral factors such as electrode position and integrity of remaining spiral ganglion neurons. Suboptimal positioning of the electrode array has been associated with poorer speech outcomes; however, postoperative computerized tomography (CT) scans are often not available to clinicians. CT-estimated electrode-to-modiolus distance (distance from the inner wall of the cochlea) has been shown to account for some variability in behavioral thresholds. However, psychophysical tuning curves (PTCs) may provide additional insight into site-specific variation in channel interaction. Thirteen unilaterally implanted adults with the Advanced Bionics HiRes90K device participated. Behavioral thresholds and PTCs were collected for all available electrodes with steered quadrupolar (sQP) configuration, using a modified threshold sweep procedure, used in Bierer et al. (Trends Hear 19:1–12, 2015). PTC bandwidths were quantified to characterize channel interaction across the electrode array, and tip shifts were assessed to identify possible contributions of neural dead regions. Broader PTC bandwidths were correlated with electrodes farther from the modiolus, but not correlated with sQP threshold, though a trend was observed. Both measures were affected by scalar location, and PTC tip shifts were observed for electrodes farther from the modiolus. sQP threshold was the only variable correlated with word recognition. These results suggest PTCs may be used as a site-specific measure of channel interaction that correlates with electrode position in some CI listeners.


psychophysical tuning curves cochlear implants electrode position imaging psychophysics 



The authors would like to acknowledge Kelly Jahn for assisting with data collection, Timothy Holden for analyzing the CT scans, and our subjects for their time and dedication.

Funding Information

This study received funding from RO1 DC012142 (JGA) and T32 DC 000033 (University of Washington Speech and Hearing Sciences: LAD).

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest.


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Copyright information

© Association for Research in Otolaryngology 2018

Authors and Affiliations

  1. 1.Department of Speech and Hearing SciencesUniversity of WashingtonSeattleUSA

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