Cochlear implants (CIs) provide excellent functional hearing to most deaf individuals, but the benefits are limited when listening in noise or to complex sounds like music. To improve cochlear implant performance we need to identify the most important cues for these difficult listening situations and find ways to present these cues through the implant. Improving spectral selectivity should improve implant performance but is limited by physical, biological and perceptual factors. For an individual implant listener, spectra selectivity may be limited by poor electrode placement and/or poor nerve survival. New techniques (current focusing) have been investigated to reduce current spread and therefore improve spectral selectivity. However, data from our lab suggest that current focusing only reduces spread of excitation (SOE) in about half of the patients tested. Performance improvements from current focusing can only be expected when the SOE is actually reduced. In the proposed experiments, we will provide the first within-subject's measurements of changes in speech in noise and music tasks (Specific Aim 3) as they relate to changes in multi-channel spectral pattern discrimination (Specific Aim 2) and reduction in single-channel SOE (Specific Aim 1). We expect to find that current focusing can result in reductions in SOE, which in turn will produce improvements in speech in noise and music performance. However, because of local neural survival, electrode placement, and variable local impedances, we expect to find that a reduction in SOE will only be achievable in a subset of patients. Therefore, we will also investigate quick (and clinically relevant) methods of predicting which patients will benefit from current focusing (experiments 2 and 3). The overall goals of this research are to determine if functional spectral resolution can be improved via current focusing for some patients and to determine in a clinically relevant procedure which patients would benefit from current focusing. We hypothesize that if current focusing can reduce the spread of excitation, then spectral resolution will be increased and improve CI performance in challenging listening conditions (e.g., speech in noise, music). The proposed research is significant because it aims to: a) evaluate the relationship between changes in SOE, multi-channel discrimination, and performance in speech and music tasks, b) improve performance for CI listeners. The research is innovative as the first study to investigate within subjects the effect of single-channel SOE on multi-channel spectral and speech processor performance by directly manipulating the degree of current spread. The research approach combines objective measures (ECAPs), subjective descriptors, single- and multi-channel psychophysics, and evaluations of experimental signal processing to better understand who might benefit from current focusing, and under what circumstances.

Public Health Relevance

Cochlear implant (CI) users have difficulty in challenging listening conditions (e.g. speech in noise and music perception) presumably because of channel interactions from each electrode. We will investigate if """"""""current-focusing"""""""" will reduce the spread of excitation, increase multi-channel spectral resolution, and provide better performance in difficult listening conditions. Furthermore, we will investigate quick (i.e. clinically-relevant) methods of determining which patients would benefit from restricting the spread of excitation.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
1R01DC012152-01A1
Application #
8373787
Study Section
Auditory System Study Section (AUD)
Program Officer
Donahue, Amy
Project Start
2012-08-15
Project End
2017-07-31
Budget Start
2012-08-15
Budget End
2013-07-31
Support Year
1
Fiscal Year
2012
Total Cost
$446,250
Indirect Cost
$196,250
Name
House Research Institute
Department
Type
DUNS #
062076989
City
Los Angeles
State
CA
Country
United States
Zip Code
90057
Landsberger, David M; Marozeau, Jeremy; Mertens, Griet et al. (2018) The relationship between time and place coding with cochlear implants with long electrode arrays. J Acoust Soc Am 144:EL509
Klawitter, Silke; Landsberger, David M; Büchner, Andreas et al. (2018) Perceptual changes with monopolar and phantom electrode stimulation. Hear Res 359:64-75
Preston, Jonathan L; Holliman-Lopez, Gabriela; Leece, Megan C (2018) Do Participants Report Any Undesired Effects in Ultrasound Speech Therapy? Am J Speech Lang Pathol 27:813-818
Stupak, Natalia; Padilla, Monica; Morse, Robert P et al. (2018) Perceptual Differences Between Low-Frequency Analog and Pulsatile Stimulation as Shown by Single- and Multidimensional Scaling. Trends Hear 22:2331216518807535
Soleymani, Roozbeh; Selesnick, Ivan W; Landsberger, David M (2018) SEDA: A tunable Q-factor wavelet-based noise reduction algorithm for multi-talker babble. Speech Commun 96:102-115
Todd, Ann E; Landsberger, David M (2018) The effect of polarity order and electrode-activation order on loudness in cochlear implant users. J Acoust Soc Am 144:EL112
Landsberger, David M; Padilla, Monica; Martinez, Amy S et al. (2018) Spectral-Temporal Modulated Ripple Discrimination by Children With Cochlear Implants. Ear Hear 39:60-68
Padilla, Monica; Stupak, Natalia; Landsberger, David M (2017) Pitch ranking with different virtual channel configurations in electrical hearing. Hear Res 348:54-62
Stelmach, Julia; Landsberger, David M; Padilla, Monica et al. (2017) Determining the minimum number of electrodes that need to be pitch matched to accurately estimate pitch matches across the array. Int J Audiol 56:894-899
Nogueira, Waldo; Litvak, Leonid M; Landsberger, David M et al. (2017) Loudness and pitch perception using Dynamically Compensated Virtual Channels. Hear Res 344:223-234

Showing the most recent 10 out of 26 publications