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DOI: 10.1055/s-0040-1718701
Prediction of Behavioral T/C Levels in Cochlear Implant Patients Based Upon Analysis of Electrode Impedances
Abstract
Background Fitting cochlear implants in babies and noncooperative patients is cumbersome and time consuming. Therefore, objective parameters have been sought in order to predict the subjective threshold (T) and maximum comfort (C) levels. Measurements of the electrically evoked compound action potentials (ECAPs) have been widely used for this purpose, yet the correlation between these objective measures and the subjective T/C levels is weak to moderate.
Purpose This article aims (1) to evaluate correlations between the subjective parameters of the fitting maps such as thresholds (T level) and maximum comfort levels (C level), the impedance of the electrode contacts, and the ECAP thresholds, and (2) to compare the value of the electrode impedances and the ECAP measures for prediction of the T/C levels.
Research Design Case review study in a quaternary otologic referral center.
Study Sample Ninety-eight consecutive CI patients were enrolled. The average age of the patients was 49 years. All patients were users of the Nucleus 24RECA (Freedom, Contour Advance-of-Stylet electrode) cochlear implant.
Data Collection and Analysis Data on impedance of the electrode contacts and the behavioral T/C levels at the first fitting session (2–5 weeks after surgery) and at the 5th fitting session (4–6 months after surgery) have been retrospectively collected in 98 consecutive CI patients. Additionally, the intraoperative impedance values and the ECAP thresholds (tNRT) have been recorded.
Results Impedances of electrode contacts show significant strong negative correlations with the stabilized T/C levels at 4 to 6 months after implantation and are an important predictor for the behavioral T/C levels. They can explain R 2 = 28 to 41% of the variability of the behavioral T/C levels. In multiple regression analysis electrode contact impedances can explain twice as much of the variability of the stabilized T/C levels than the tNRT values. The electrode impedances together with the tNRT values are able to explain R 2 = 37 to 40% of the global variability of the T/C levels while the tNRT thresholds solely are able to explain only R 2 = 5 to 14% of the T/C levels variability.
Conclusion Impedances of electrode contacts correlate strongly with the stabilized behavioral T/C levels and may be used as an objective measure for fitting of cochlear implants.
* The first two authors contributed equally to this manuscript.
Publication History
Received: 02 December 2019
Accepted: 14 February 2020
Article published online:
08 February 2021
© 2021. American Academy of Audiology. This article is published by Thieme.
Thieme Medical Publishers, Inc.
333 Seventh Avenue, 18th Floor, New York, NY 10001, USA
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References
- 1 Holstad BA, Sonneveldt VG, Fears BT. et al. Relation of electrically evoked compound action potential thresholds to behavioral T- and C-levels in children with cochlear implants. Ear Hear 2009; 30 (01) 115-127
- 2 Potts LG, Skinner MW, Gotter BD, Strube MJ, Brenner CA. Relation between neural response telemetry thresholds, T- and C-levels, and loudness judgments in 12 adult nucleus 24 cochlear implant recipients. Ear Hear 2007; 28 (04) 495-511
- 3 Tao Y, Zheng Y, Wang K, Meng Z, Xu K, Xie T. Compare NRT threshold and behavior T-level in cochlear implant patients [in Chinese]. Lin Chung Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2011; 25 (04) 162-165
- 4 Vlahović S, Šindija B, Aras I, Glunčić M, Trotić R. Differences between electrically evoked compound action potential (ECAP) and behavioral measures in children with cochlear implants operated in the school age vs. operated in the first years of life. Int J Pediatr Otorhinolaryngol 2012; 76 (05) 731-739
- 5 Greisiger R, Shallop JK, Hol PK, Elle OJ, Jablonski GE. Cochlear implantees: analysis of behavioral and objective measures for a clinical population of various age groups. Cochlear Implants Int 2015; 16 (Suppl. 04) 1-19
- 6 King JE, Polak M, Hodges AV, Payne S, Telischi FF. Use of neural response telemetry measures to objectively set the comfort levels in the Nucleus 24 cochlear implant. J Am Acad Audiol 2006; 17 (06) 413-431 , quiz 462
- 7 Molisz A, Zarowski A, Vermeiren A. et al. Postimplantation changes of electrophysiological parameters in patients with cochlear implants. Audiol Neurotol 2015; 20 (04) 222-228
- 8 Schmitt H, Roemer A, Zeilinger C. et al. Heat shock proteins in human perilymph: implications for cochlear implantation. Otol Neurotol 2018; 39 (01) 37-44
- 9 Lin HC, Ren Y, Lysaght AC, Kao SY, Stankovic KM. Proteome of normal human perilymph and perilymph from people with disabling vertigo. PLoS One 2019; 14 (06) e0218292
- 10 Mittal R, Panwar SS. Correlation between intra-operative high rate neural response telemetry measurements and behaviourally obtained threshold and comfort levels in patients using Nucleus 24 cochlear implants. Cochlear Implants Int 2009; 10 (02) 103-111
- 11 Muhaimeed HA, Anazy FA, Hamed O, Shubair E. Correlation between NRT measurement level and behavioral levels in pediatrics cochlear implant patients. Int J Pediatr Otorhinolaryngol 2010; 74 (04) 356-360
- 12 McKay CM, Smale N. The relation between ECAP measurements and the effect of rate on behavioral thresholds in cochlear implant users. Hear Res 2017; 346: 62-70