During the last decade, cochlear implantation has evolved into a well-established treatment of deafness, predominantly because of many improvements in speech processing and the controlled excitation of the auditory nerve. Cochlear implants now also feature telemetry, which is highly useful to monitor the proper functioning of the implanted electronics and electrode contacts. Telemetry can also support the clinical management in young children and difficult cases where neural unresponsiveness is suspected. This article will review recent advances in the telemetry of the electrically evoked compound action potential that have made these measurements simple and routine procedures in most cases. The distribution of the electrical stimulus itself sampled by “electrical field imaging” reveals general patterns of current flow in the normal cochlea and gross abnormalities in individual patients; models have been developed to derive more subtle insights from an individual electrical field imaging. Finally, some thoughts are given to the extended application of telemetry, for example, in monitoring the neural responses or in combination with other treatments of the deaf ear.
Schoonhoven R., Lamore PJ, de Laat JA, Grote JJThe prognostic value of electrocochleography in severely hearing-impaired infants. Audiology.1999;38:141-154.
5.
Klop Wmc, Hartlooper A., Briare JJ, Frijns Jhm.A new method for dealing with the stimulus artefact in electrically evoked compound action potential measurements. Acta Otolaryngol.2004;124:137-143.
Charlet deSauvage R., Cazals Y., Erre JP, Aran JMAcoustically derived auditory nerve action potential evoked by electrical stimulation: an estimation of the waveform of single unit contribution. J Acoust Soc Am.1983;73:616-627.
8.
Brown CJ, Abbas PJ, Gantz B.Electrically evoked whole-nerve action potentials: data from human cochlear implant users. J Acoust Soc Am. 1990;88:1385-1391.
9.
Brown CJ, Hughes ML, Luk B., Abbas PJ, Wolaver A., Gervais J.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.
Battmer RD, Dillier N., Lai WK, et al. Evaluation of the neural response telemetry (NRT) capabilities of the nucleus research platform 8: initial results from the NRT trial. Int J Audiol.2004;43:S10-S15.
11.
Charasse B. , Thai-Van H, Chanal JM, Berger-Vachon C, Collet L. Automatic analysis of auditory nerve electrically evoked compound action potential with an artificial neural network. Artif Intell Med.2004;31:221-229.
12.
Botros A., van Dijk B., Killian M.AutoNRT™: an automated system that measures ECAP thresholds with the Nucleus(r) Freedom™ cochlear implant via machine intelligence. Artif Intell Med.2007;40:15-28. Epub 2006 Aug 22.
13.
Marsh.A new stimulus for promonoty E-ABR. Paper presented at: 1993 Conference on implantable auditory prostheses; July 11-15, 1993; Smithfield, RI.
14.
Mason S.Electrophysiologic and objective monitoring of the cochlear implant during surgery: implementation, audit and outcomes. Int J Audiol.2004;43:S33-S38.
15.
Kreft HA, Donaldson GS, Nelson DAEffects of pulse rate on threshold and dynamic range in Clarion cochlear-implant users. J Acoust Soc Am.2004;115(5Pt1): 1885-1888.
16.
Shannon RVThreshold and loudness functions for pulsatile stimulation of cochlear implants . Hear Res. 1985; 18:135-143.
17.
Vischer M., Haenggeli A., Zhang J., Pelizzone M., Hausler R., Rouiller EMEffect of high-frequency electrical stimulation of the auditory nerve in an animal model of cochlear implants. Am J Otol.1997;18(6 Suppl.):S27-S29.
18.
Cafarelli-Dees D., Dillier N., Lai WK, et al. Normative findings of electrically evoked compound action potential measurements using the neural response telemetry of the Nucleus CI24M cochlear implant system. Audiol Neurootol.2005;10:105-116.
19.
Hughes ML, Brown CJ, Abbas PJ, Wolaver AA, Gervais JPComparison of EAP thresholds with MAP levels in the nucleus 24 cochlear implant: data from children. Ear Hear.2000;21:164-174.
20.
Mason SM, Cope Y., Garnham J., O'Donoghue GM, Gibbin KPIntra-operative recordings of electrically evoked auditory nerve action potentials in young children by use of neural response telemetry with the Nucleus CI24M cochlear implant. Br J Audiol.2001;35:225-235.
21.
Franck KHA model of a nucleus 24 cochlear implant fitting protocol based on the electrically evoked whole nerve action potential. Ear Hear.2002;23(1 Suppl):67S-71S.
22.
Zimmerling MJ, Hochmair ESEAP recordings in ineraid patients—correlations with psychophysical measures and possible implications for patient fitting . Ear Hear.2002;23:81-91.
23.
Thai-Van H. , Truy E., Charasse B., et al. Modeling the relationship between psychophysical perception and electrically evoked compound action potential threshold in young cochlear implant recipients: clinical implications for implant fitting. Clin Neurophysiol.2004;115: 2811-2824.
24.
Gordon KA, Papsin BC, Harrison RVToward a battery of behavioral and objective measures to achieve optimal cochlear implant stimulation levels in children. Ear Hear.2004;25:447-463.
25.
Smoorenburg GF, Willeboer C., van Dijk JESpeech perception in nucleus C124M cochlear implant users with processor settings based on electrically evoked compound action potential thresholds. Audiol Neurootol.2002;7:335-347.
26.
McKay CM, Fewster L., Dawson P.A different approach to using neural response telemetry for automated cochlear implant processor programming. Ear Hear. 2005 ;26(4 Suppl.):38S-44S.
27.
Brown CJClinical uses of electrically evoked auditory nerve and brainstem responses . Curr Opin Otolaryngol Head Neck Surg.2003 ;11:383-387.
28.
Seyle K., Brown CJSpeech perception using maps based on neural response telemetry measures. Ear Hear. 2002;23(1 Suppl.):72S-79S.
29.
Sun YS, Wu CM, Liu TCMandarin speech perception in nucleus CI 24 implantees using MAPs based on neural response telemetry. ORLJ Otorhinolaryngol Relat Spec . 2004;66:255-261.
30.
Kaplan-Neeman R., Henkin Y., Yakir Z., et al. NRT-based versus behavioral-based MAP: a comparison of parameters and speech perception in young children. J Basic Clin Physiol Pharmacol.2004;15:57-69.
31.
Kiefer J., Hohl S., Sturzebecher E., Pfennigdorff T., Gstoettner W.Comparison of speech recognition with different speech coding strategies (SPEAK, CIS, and ACE) and their relationship to telemetric measures of compound action potentials in the nucleus CI 24M cochlear implant system. Audiology. 2001;40:32-42.
32.
Shpak T., Berlin M., Luntz M.Objective measurements of auditory nerve recovery function in nucleus CI 24 implantees in relation to subjective preference of stimulation rate. Acta Otolaryngol.2004;124:679-683.
33.
Gantz BJ, Brown CJ, Abbas PJIntraoperative measures of electrically evoked auditory nerve compound action potential. Am J Otol.1994;15:137-144.
34.
Franck KH, Norton SJEstimation 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.
35.
Cohen LT, Saunders E., Richardson LMSpatial spread of neural excitation: comparison of compound action potential and forward-masking data in cochlear implant recipients. Int J Audiol. 2004;43:346-355.
36.
Eisen MD, Franck KHElectrode interaction in pediatric cochlear implant subjects. J Assoc Res Otolaryngol.2005;6:160-170.
37.
Hughes ML, Abbas PJThe relation between electrophysiologic channel interaction and electrode pitch ranking in cochlear implant recipients. J Acoust Soc Am. 2006;119:1527-1537.
38.
Cohen LT, Richardson LM, Saunders E., Cowan Rsc.Spatial spread of neural excitation in cochlear implant recipients: comparison of improved ECAP method and psychophysical forward masking. Hear Res. 2003; 179:72-87.
39.
Fayad JN, Linthicum FHMultichannel cochlear implants: relation of histopathology to performance . Laryngoscope.2006;116:1310-1320.
40.
Ifukube T., White RLCurrent distributions produced inside and outside the cochlea from a scala tympani electrode array. IEEE Trans Biomed Eng. 1987;34:883-890.
41.
Jolly CN, Spelman FA, Clopton BMQuadrupolar stimulation for cochlear prostheses: modeling and experimental data. IEEE Trans Biomed Eng. 1996;43: 857-865.
42.
Kral A., Hartmann R., Mortazavi D., Klinke R.Spatial resolution of cochlear implants: the electrical field and excitation of auditory afferents. Hear Res. 1998;121:11-28.
43.
O'Leary SJ, Black RC, Clark GMCurrent distributions in the cat cochlea: a modelling and electrophysiological study. Hear Res.1985;18:273-281.
44.
Kasper A., Pelizzone M., Montandon P.Intracochlear potential distribution with intracochlear and extra-cochlear electrical stimulation in humans. Ann Otol Rhinol Laryngol.1991;100:812-816.
45.
Mens Lhm, Van den Broek P.Telemetry of longitudinal current spread: does it show spatial selectivity ? Paper presented at: 1997 Conference on Implantable Auditory Prostheses; August 12-21, 1997; Pacific Grove, CA.
46.
Mens Lhm, Boyle PJ, Mulder JJThe Clarion electrode positioner: approximation to the medial wall and current focussing? Audiol Neurotol. 2003;8:166-175.
47.
Faltys M., Griffith G., Segel P., et al. Electrical field imaging methodology. Paper presented at: Conference on Implantable Auditory Prostheses; August 19-24, 2001; Asilomar, Pacific Grove, CA.
48.
Vanpoucke FJ, Zarowski AJ, Peeters SAIdentification of the impedance model of an implanted cochlear prosthesis from intracochlear potential measurements. IEEE Trans Biomed Eng. 2004;51:2174-2183.
49.
Mens Lhm, Huiskamp G, Broek Pvd, Oostendorp TF. Modelling surface potentials from intra-cochlear electrical stimulation. Scand Audiol.1999;28:249-255.
50.
Mens Lhm, Oostendorp TF, Van den Broek P.Cochlear implant generated surface potentials: current spread and side effects . Ear Hear.1994;15:339-345.
51.
Suesserman MF, Spelman FALumped-parameter model for in vivo cochlear stimulation. IEEE Trans Biomed Eng. 1993;40:237-245.
52.
Vanpoucke F. , Zarowski A., Casselman J., Frijns J., Peeters S.The facial nerve canal: an important cochlear conduction path revealed by Clarion electrical field imaging. Otol Neurotol. 2004;25:282-289.
53.
Sprögel J.Untersuchungen der elektrsichen Feldausbreitung in de Cochlea unter Berücksichtigung des Elektrodensystems. Hannover, Germany: Medizinischen Hochschule Hannover; 2006.
54.
Mens Lhm.Telemetry: features and applications. In: Cullington HE, ed. Cochlear Implants: Objective Measures . London, England: Whurr; 2003:23-39.
55.
Balkany TJ, Hodges AV, Buchman CA, et al. Cochlear implant soft failures consensus development conference statement. Otol Neurotol. 2005;26:815-818.
56.
Mauch H., Möller C., Nevison B.Diagnosing implant failures with the nucleus integrity test system. Paper presented at: Fourth International Symposium and Workshops: Objective Measures in Cochlear Implants; June 1-4, 2005; Hannover, Germany.
57.
Carter P.Determining electrode faults using different stimulation modes. Paper presented at: XVI World Congress of ORL—Head and Neck Surgery1997; Sydney, Australia.
58.
Marzella PL , Clark GMGrowth factors, auditory neurones and cochlear implants: a review. Acta Otolaryngol.1999 ; 119:407-412.
59.
Miller AL, Prieskorn DM, Altschuler RA, Miller JMMechanism of electrical stimulation-induced neuroprotection: effects of verapamil on protection of primary auditory afferents. Brain Res.2003;966:218-230.
