Abstract
Objective: To describe the principles and operation of a new telemetry-based function test for the Nucleus® cochlear implant, known as the CS19 Intra-Cochlear Impedance Matrix (IIM) and to present results from a multicentre clinical study to establish reproducibility (test-retest reliability) and normative ranges.
Method: The IIM test measures bipolar impedances between all electrode pairs and employs a normalization procedure based on common ground impedances in order to identify abnormal current paths among electrodes. Six European clinics collected IIM data from a total of 192 devices.
Results: Reproducibility was high between initial and repeat measurements. The normative analysis demonstrated narrow ranges among devices after normalization of impedance data. The IIM is able to identify abnormal current paths that are not evident from standard impedance telemetry and may otherwise only be found utilising average electrode voltage measurements (AEV).
Conclusions: The IIM test was found to be straightforward to perform clinically and demonstrated reproducible data with narrow ranges in normally-functioning devices. Because this test uses a very low stimulation level the IIM test is well suited for children or multiply handicapped CI users who cannot reliably report on their auditory percepts. The new algorithms show potential to improve implant integrity testing capabilities if implemented in future clinical software.
Acknowledgments
This study was supported by Cochlear Europe. We would like to thank Dr Paul Boyd (Consultant with Cochlear Europe) for assistance in preparing this report. Special thanks to other staff at the clinics: Bengt Almqvist (Lund), Torsten Wohlberedt (Erlangen).
Declaration of interest: HM is an employee of Cochlear Europe, the manufacturer of the device used in the present study. For the other authors no conflicts of interest are declared. The costs of this study were covered by Cochlear.
References
[1] Balkany TJ, Hodges AV, Buchman CA, et al. Cochlear implant soft failures. Consensus Development Conference Statement. Cochlear Implants Int 2005; 6: 105–122.10.1179/cim.2005.6.3.105Search in Google Scholar
[2] Battmer RD, Backous DD, Balkany TJ, et al. International classification of reliability for implanted cochlear implant receiver stimulators. Otol Neurotol 2010; 31: 1190–1193.10.1097/MAO.0b013e3181d2798eSearch in Google Scholar
[3] Battmer RD, Gnadeberg D, Lehnhardt E, Lenarz T. An integrity test battery for the Nucleus Mini 22 cochlear implant system. Eur Arch Otorhinolaryngol 1994; 251: 205–209.10.1007/BF00628424Search in Google Scholar
[4] Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Int J Nurs Stud 2010; 47: 931–936.10.1016/j.ijnurstu.2009.10.001Search in Google Scholar
[5] Botros A, van Dijk B, Killian M. AutoNRT: an automated system that measures ECAP thresholds with the Nucleus freedom cochlear implant via machine intelligence. Artif Intell Med 2007; 40: 15–28.10.1016/j.artmed.2006.06.003Search in Google Scholar
[6] Brown CJ, Hughes ML, Luk B. The relationship between EAP and EABR thresholds and levels used to program the nucleus 24 speech processor: data from adults. Ear Hear 2000; 21: 151–163.10.1097/00003446-200004000-00009Search in Google Scholar
[7] Büchner A, Frohne-Buechner C, Stoever T, Gaertner L, Battmer RD, Lenarz T. Comparison of a paired or sequential stimulation paradigm with advanced bionics’ high-resolution mode. Otol Neurotol 2005; 26: 941–947.10.1097/01.mao.0000185069.27705.f0Search in Google Scholar
[8] Busby PA, Plant KL, Whitford LA. Electrode impedance in adults and children using the Nucleus 24 cochlear implant system. Cochlear Implants Int 2002; 3: 87–103.10.1179/cim.2002.3.2.87Search in Google Scholar
[9] Carlson ML, Archibald DJ, Dabade TS, et al. Prevalence and timing of individual cochlear implant electrode failures. Otol Neurotol 2010; 31: 893–898.10.1097/MAO.0b013e3181d2d697Search in Google Scholar
[10] Choi CT, Lai W, Lee S. A novel approach to compute the impedance matrix of a cochlear implant system incorporating an electrode-tissue interface based on finite element method. IEEE Trans Magn 2006; 42: 1375–1378.10.1109/TMAG.2006.872461Search in Google Scholar
[11] Cinar BC, Atas A, Sennaroglu G, Sennaroglu L. Evaluation of objective test techniques in cochlear implant users with inner ear malformations. Otol Neurotol 2011; 32: 1065–1074.10.1097/MAO.0b013e318229d4afSearch in Google Scholar
[12] Clark G. The multi-channel cochlear implant and the relief of severe-to-profound deafness. Cochlear Implants Int 2012; 13: 69–85.10.1179/1754762811Y.0000000019Search in Google Scholar
[13] Cullen RD, Fayad JN, Luxford WM, Buchman CA. Revision cochlear implant surgery in children. Otol Neurotol 2008; 29: 214–220.10.1097/MAO.0b013e3181635e9aSearch in Google Scholar
[14] Dillier N, Lai WK, Almqvist B, et al. Measurement of the electrically evoked compound action potential via a neural response telemetry system. Ann Otol Rhinol Laryngol 2002; 111: 407–414.10.1177/000348940211100505Search in Google Scholar
[15] Fadeeva E, Linke I, Lenarz T, Chichkov B, Paasche G. Surface patterning of cochlear implant electrode arrays. Biomed Tech 2013; 58(Suppl 1): 1–2.10.1515/bmt-2013-4048Search in Google Scholar
[16] Franck KH, Norton SJ. Estimation of psychophysical levels using the electrically evoked compound action potential measured with the neural response telemetry capabilities of Cochlear Corporation’s CI24M device. Ear Hear 2001; 22: 289–299.10.1097/00003446-200108000-00004Search in Google Scholar
[17] Garnham J, Marsden J, Mason SM. Profiles of AEVs for intra- and post-operative integrity test measurements in young children with the Nucleus mini 22 cochlear implant. Br J Audiol 2001; 35: 31–42.10.1080/03005364.2001.11742729Search in Google Scholar
[18] Gärtner L, Lenarz T, Joseph G, Büchner A. Clinical use of a system for the automated recording and analysis of electrically evoked compound action potentials (ECAPs) in cochlear implant patients. Acta Otolaryngol 2010; 130: 724–732.10.3109/00016480903380539Search in Google Scholar
[19] Goehring JL, Hughes ML, Baudhuin JL, Lusk RP. How well do cochlear implant intraoperative impedance measures predict postoperative electrode function? Otol Neurotol 2013; 34: 239–244.10.1097/MAO.0b013e31827c9d71Search in Google Scholar
[20] Gosepath J, Lippert K, Keilmann A, Mann WJ. Analysis of fifty-six cochlear implant device failures. ORL J Otorhinolaryngol Relat Spec 2009; 71: 142–147.10.1159/000212756Search in Google Scholar
[21] Grolman W, Maat A, Verdam F, et al. Spread of excitation measurements for the detection of electrode array foldovers: a prospective study comparing 3-dimensional rotational x-ray and intraoperative spread of excitation measurements. Otol Neurotol 2009; 30: 27–33.10.1097/MAO.0b013e31818f57abSearch in Google Scholar
[22] Hodges AV, Balkany TJ, Ruth RA, et al. Electrical middle ear muscle reflex: use in cochlear implant programming. Otolaryngology Head Neck Surg 1997; 117: 255–261.10.1016/S0194-5998(97)70183-9Search in Google Scholar
[23] Hughes ML, Brown CJ, Abbas PJ. Sensitivity and specificity of averaged electrode voltage measures in cochlear implant recipients. Ear Hear 2004; 25: 4314–4346.10.1097/01.aud.0000145111.92825.ccSearch in Google Scholar
[24] Lin JW, Mody A, Tonini R, et al. Characteristics of malfunctioning channels in pediatric cochlear implants. Laryngoscope 2010; 120: 399–404.10.1002/lary.20668Search in Google Scholar
[25] Mahoney MJ, Proctor LA. The use of averaged electrode voltage to assess the function of Nucleus internal cochlear implant devices in children. Ear Hear 1994; 15: 177–183.10.1097/00003446-199404000-00007Search in Google Scholar
[26] Marlowe AL, Chinnici JE, Rivas A, Niparko JK, Francis HW. Revision cochlear implant surgery in children: the Johns Hopkins experience. Otol Neurotol 2010; 31: 74–82.10.1097/MAO.0b013e3181c29fadSearch in Google Scholar
[27] Mason S. Electrophysiologic and objective monitoring of the cochlear implant during surgery: implementation, audit and outcomes. Int J Audiol 2004: 43(Suppl 1): S33–S38.Search in Google Scholar
[28] Mens LH. Advances in cochlear implant telemetry: evoked neural responses, electrical field imaging, and technical integrity. Trends Amplif 2007; 11: 143–159.10.1177/1084713807304362Search in Google Scholar
[29] Mens LH, Oostendorp T, van den Broek P. Identifying electrode failures with cochlear implant generated surface potentials. Ear Hear 1994; 15: 330–338.10.1097/00003446-199408000-00007Search in Google Scholar
[30] Monin DL, Kazahaya K, Franck KH. Routine use of the crystal device integrity testing system in pediatric patients. J Am Acad Audiol 2006; 17: 722–732.10.3766/jaaa.17.10.4Search in Google Scholar
[31] Müller-Deile J, Böhnke B. Clinical spread of excitation measurement. Presented at the 9th European Symposium on Paediatric Cochlear Implantation, Warsaw, Poland, May 2009.Search in Google Scholar
[32] Müller-Deile J, Kortmann T, Mauch H, et al. Advances in integrity testing for Nucleus implants. Presented at the 6th International Symposium on Objective Measures in Auditory Implants, St. Louis, USA, September 2010.Search in Google Scholar
[33] Neuburger J, Lenarz T, Lesinski-Schiedat A, Büchner A. Spontaneous increases in impedance following cochlear implantation: suspected causes and management. Int J Audiol 2009; 48: 233–239.10.1080/14992020802600808Search in Google Scholar
[34] Patrick JF, Busby PA, Gibson PJ. The development of the Nucleus Freedom Cochlear implant system. Trends Amplif 2006; 10: 175–200.10.1177/1084713806296386Search in Google Scholar
[35] Rotteveel LJ, Proops DW, Ramsden RT, Saeed SR, van Olphen AF, Mylanus EA. Cochlear implantation in 53 patients with otosclerosis: demographics, computed tomographic scanning, surgery, and complications. Otol Neurotol 2004; 25: 943–952.10.1097/00129492-200411000-00014Search in Google Scholar
[36] Schuettler M, Stieglitz T. Intelligent telemetric implants. Biomed Tech 2012; 57 (Suppl. 1): 967–970.10.1515/bmt-2012-4255Search in Google Scholar
[37] Trosman S, Matusik DK, Ferro L, Gao W, Saadia-Redleaf M. Presbycusis occurs after cochlear implantation also: a retrospective study of pure tone thresholds over time. Otol Neurotol 2012; 33: 1543–1548.10.1097/MAO.0b013e318271c1efSearch in Google Scholar
[38] Tykocinski M, Cohen LT, Cowan RS. Measurement and analysis of access resistance and polarization impedance in cochlear implant recipients. Otol Neurotol 2005; 26: 948–956.10.1097/01.mao.0000185056.99888.f3Search in Google Scholar
[39] van Dijk B, Botros AM, Battmer RD, et al. Clinical results of AutoNRT, a completely automatic ECAP recording system for cochlear implants. Ear Hear 2007; 28: 558–570.10.1097/AUD.0b013e31806dc1d1Search in Google Scholar
[40] Vanpoucke FJ, Zarowski AJ, Peeters SA. Identification of the impedance model of an implanted cochlear prosthesis from intracochlear potential measurements. IEEE Trans Biomed Eng 2004; 51: 2174–2183.10.1109/TBME.2004.836518Search in Google Scholar
[41] Vargas JL, Sainz M, Roldan C, Alvarez I, de la Torre A. Long-term evolution of the electrical stimulation levels for cochlear implant patients. Clin Exp Otorhinolaryngol 2012; 5: 194–200.10.3342/ceo.2012.5.4.194Search in Google Scholar
[42] Von Rohr R. Cochlear implant impedance telemetry measurements and model calculations to estimate modiolar currents. Master Thesis, Zurich: ETH and University Hospital 2011.Search in Google Scholar
[43] Zeitler DM, Lalwani AK, Roland JT Jr, Habib MG, Gudis D, Waltzman SB. The effects of cochlear implant electrode deactivation on speech perception and in predicting device failure. Otol Neurotol 2009: 30: 7–13.10.1097/MAO.0b013e31818a08baSearch in Google Scholar
[44] Zierhofer CM, Hochmair IJ, Hochmair ES. The advanced Combi 40+ cochlear implant. Am J Otol 1997;18(6 Suppl): S37–S38.Search in Google Scholar
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