Memoire Online - Contrainte Psycho-Physiques et Electrophysiologiques sur le codage de la stimulation électrique chez les sujets porteurs d'un implant cochléaire

J. Wable, T. van den Abbeele, S. Gallégo, B. Frachet
Accepté dans Electroencephalography and clinical Neurophysiology

Cette étude met en évidence un effet de la cadence de stimulation sur l'amplitude des potentiels évoqués de latence tardive avec une réponse P1N1 plus ample pour les stimuli déviants que pour les stimuli standards.

Une onde de discordance est obtenue lors de la stimulation de deux électrodes différentes, l'une de manière fréquente, l'autre de manière rare. Une négativité est observée lorsque la différence des potentiels est effectuée entre celui évoqué par le stimulus déviant et celui évoqué par le stimulus standard lorsqu'ils sont physiquement différents mais également lorsqu'ils sont physiquement identiques. Aucun effet sur la latence ou l'amplitude de la négativité en fonction de l'éloignement à l'électrode de référence n'est mis en évidence, ce qui suggère que les différentes taches présentent la même difficulté. La latence de la MMN est précoce comparée aux données de Kraus et al. (1993b), ce qui peut s'expliquer par les différences de stimulation (champ libre / stimulation directe de l'implant) ou par un traitement central moins complexe dans le cas de stimulations localisées que dans le cas de sons de parole.

Mismatch negativity: a tool for the assessment of stimuli discrimination in cochlear implant subjects.

Jocelyne Wable ¹, Thierry van den Abbeele ², Stéphane Gallégo ³, Bruno Frachet ¹

Centre de Recherche et d'Ingénierie des Sciences et Techniques de l'Audition et du Langage (CRISTAL),

Université Paris 13, Hôpital Avicenne, Service ORL, 125 rue de Stalingrad, 93009 Bobigny.

² Hôpital Robert Debré, service ORL, 48 Boulevard Serurier, 75019 Paris, France.

Jocelyne Wable, CRISTAL, Hôpital Avicenne, Service ORL, 125 rue de Stalingrad, 93009 Bobigny. Tel: (33) 1 48 95 59 07, fax: (33) 1 48 95 52 02, e-mail
· jocelyne.wable@avc.ap-hop-paris.fr

keywords: event-related electrically evoked auditory potentials, mismatch negativity, cochlear implant, electrical stimulation, discrimination, speech perception, human.

Among cochlear implant users performance vary a lot. Cognitive abilities may be involved in this variability. The mismatch negativity should provide an index of discrimination in cochlear implantees (Kraus et al., 1993b). Our aim was to analyze MMN in cochlear implant (Digisonic) subjects to assess electrode discrimination and to study the relationship between MMN and speech performance. The mismatch was elicited by stimulating three pairs of different electrodes. Two sessions were performed with both standard and deviant stimuli reversed. Speech recognition abilities were evaluated using four speech tests. The statistics included the results of 6 subjects. They indicated that MMN may be obtained when stimulating two different electrodes. A difference occurred between standard and deviant stimuli within a session but also when the response to the deviant stimulus was compared to the response of the same stimulus in a standard condition, validating the discrimination process. MMN latency was about 140 ms, and amplitude about --2.8 i.tV. No differences were shown in respect to the electrodes spacing. No relationship between MMN and speech performance was found. The clinical application of this method might be to assess the auditory processing of electrical stimuli in congenitally deaf subjects at a preimplantation stage.

A cochlear implant consists of an electrode array placed in the scala tympani. It delivers electrical stimulation to the remaining auditory nerve fibers of deaf patients. Non-invasive and objective tools have been developed to assess auditory nerve and central auditory system functioning before and after implantation. Auditory evoked potentials have been widely used as much for evaluating the excitability of the auditory nerve before implantation and the integrity of the implant, as for facilitating the device parameters setting (Pelizone et al., 1989; Oviatt and Kileny, 1991).

Cochlear implantation success lies on speech intelligibility and speech production abilities of the patient. Implant users vary greatly in their performance. The poorer performers could benefit from parameters setting optimization at an individual level. Differences between subjects may not be entirely explained in ternis of device, ear status or number of surviving neurons. Abilities to adapt to electrical

stimulation, discrimination of stimuli, as well as cognitive capacities may be involved. Recently, relationships were found between electrically evoked brainstem responses (EABR) and speech performances (Hermann and Thornton, 1990 ; Gallégo et al., 1998 ; Groenen et al., 1997). The ability in discriminating small acoustic differences is very important for the perception and processing of speech signais. The Mismatch Negativity (MMN) method is an objective tool that provides a measure of automatic stimuli discrimination. (Nit âtânen et al., 1978; Nââtânen and Michs 1979; Nââtânen and Picton, 1987; Sams et al., 1985). This method seems likely to be interesting in the study of neurophysiologic processes of stimulus change occurring during normal perception or in pathological situations (Kraus et ai, 1993a, 1995a). MMN should provide an index of discrimination abilities.

Kraus et al. (1993b) demonstrated that MMN may be obtained in patients with cochlear implant. With 100 ms synthesized speech stimuli /da/ and /ta/, they observed some response patterns similar to those obtained in normal-hearing subjects. Ponton and Don (1995) demonstrated that the activation of two clifferent electrode pairs along the implant array elicited an MMN response. They found, with a 1-pulse stimulation, a larger and earlier MMN response for the apical electrodes than for the basal ones. Kileny et al. (1997) investigated late and cognitive evoked potentials in children with cochlear implants. They found that for the frequency contrast, shorter and stronger P3 and MMN were associated with high sentence recognition scores. Cochlear implantees may benefit from this technique in terms of electrode functioning, auditory system integrity, discrimination abilities (Kraus et al., 1993b; Ponton and Don, 1995). Moreover, it may assess evolution of capacities along training (Tremblay et al, 1997 ; Kraus et al., 1998, 1995b).

Our aim was to put forward and analyze MMN in cochlear implant subjects to assess electrode discrimination along the implant array. The main objectives were to compare event-related auditoryevoked potentials (ERPs) waves and difference waves as a fonction of the following experimental parameters: occurrence of the stimulus and stimulated electrodes. A second objective was to study the relationship between MMN and speech perception performance.

Our experiments were performed with users of Digisonic DX10 multi-electrode cochlear implant.

Eight subjects were included in the experiment, ranging in age from 40 to 71 years, having been deaf from 1 to 13 years, and having been implanted from 4 to 36 months. They were all post-lingually deafened. Details concerning etiologies, length of deafness, implant experience and stimulus parameters used in this study are displayed in Table I. All subjects wore a DIGISONIC DX 10 cochlear implant (MXM).

The DX 10 Digisonic processor signal processing consists (Beliaeff et al., 1994) in assigning to the 15 implanted electrodes 15 frequency bands ranging from 100 to 7800 Hz. The signal spectral analysis relies on a Fast Fourier Transform. Each sweep, six electrodes are stimulated, corresponding to the louder bands of the spectral analysis. The amplitude of the spectral peaks determines the amount of current delivered to the corresponding electrode, i.e., the pulse duration. The frequency bands assigned to these electrodes are spaced with a linear or a logarithmic scale. Overlapping or reassigning the frequency bands is possible. The highest pitch corresponds to the first electrode and the lowest one to the 15`^h.

During measurements the subjects were seated in a comfortable chair and were asked to relax with their eyes closed, but not to go to sleep. They were instructed not to pay attention to the stimuli. Stimulation

The stimuli did not go through the implant processor but were directly delivered through a Digisonic interface, the Digistim. Stimuli were presented using a passive oddball paradigm. Attention is directed away from the acoustic stimuli with an explicit instruction to ignore all auditory stimuli. Standard (n=850) and deviant (n=150) stimuli were presented in a pseudo-random sequence with at least three standard stimuli between two deviant ones.

The mismatch was elicited by stimulating two different electrodes. Three pairs of electrodes were tested : (13, 12), (13, 10), (13, 8). In order to avoid overlapping of the MMN with the waveform

components related to the physical difference between stimuli, two sessions were performed for each pair : the first session with stimulus 1 the repetitive standard and stimulus 2 the randomly interspersed deviant one, and the contra protocol with both stimuli reversed (Ponton and Don, 1995). The order of the sessions was randomized between subjects. The order of pairs and electrodes was randomized as well.

Both stimuli were 100 ms long, with 3 ms inter-pulse duration. The stimuli interval was 1 second. Stimulus level was set at about 70 % of the dynamic range. The subjects discriminated these stimuli behaviorally. An equal level of loudness of the electrodes 13 to 8 was researched before testing at this adjusted level. At the beginning of the electrophysiological measurements it was verified that the subjects detected all stimuli and that the loudness was comfortable.

The potentials were recorded from forehead/mastoid contralateral to the implant with the ground electrode on the chin. In this work, we used only this recording position, which is known to be a good location to measure MMN. The recordings were controlled using a home-made software. The recording window included 500 ms of post-stimulus time with 250 sampang points per sweep. The responses were amplified and analog bandpass filtered on-line from 0.1 Hz to 30 Hz with a CyberAmp 320 (Axon Instruments, Foster City). Using an automatic artifact rejection algorithm, the sweeps containing activity that exceeded #177;75 jiV were excluded from subsequent averaging. ERPs from deviant and standard stimuli were averaged separately for on-line visualization of the responses. However, each ERP was also stored separately to allow off-line analysis.

Averaged ERPs from standard and from deviant stimuli were obtained from the recording. ERPs from standard stimuli following deviant ones were not included in the averaging. The MMN, which overlaps the N1 and P2 event-related potentials components, was measured from a difference wave obtained by subtracting the response evoked by the standard stimulus from the response evoked by the deviant stimulus. Two difference waveforms were obtained: the intra-session in which stimuli were physically different (two electrodes stimulated) and the inter-session involving physically identical stimuli presented in different contexts (randomized and rare in one session vs. repetitive and frequent in

the other one). The resulting waveforms should reflect stimulus-related activities and contextual differences for the first wave, and only contextual differences for the second one. However, the contextual difference means not only deviant vs. standard stimulation but also repetition rates and number of waveforms involved (Picton et al., 1974). A lower N1 amplitude is to be expected in the case of a standard stimulation compared to a deviant one.

Four tests were administered to evaluate speech recognition abilities (Table II). For each test, the stimuli were presented in random order, at a comfortable listening level with the processor set at a normal-use setting. No lip-reading help and no feedback were provided. The VCV test assesses the ability to identify consonants. Sixteen consonants were presented through a computer with a 16-bit sound card, three Urnes each, using the vowel /a/. The subject had to choose between 16 responses presented on the computer screen. The Lafon test assesses recognition of monosyllabic words. A list contants 17 words of three phonemes. A list of 75 familiar monosyllabic words was also presented. Thirty five short sentences with 119 familiar key-words was used to assess phonetic and cognitive skills. The stimuli were presented once, in an open-set condition. The percentage of consonants, phonemes, words and keywords

Statistics only concemed the 6 subjects for whom the three pair discriminations were evaluated. The P1-N1-P2 wave was identified for each evoked potential. The N1 latencies were measured at the trough. The amplitudes were evaluated based upon the difference between P1 peak and Ni trough. The MMN waves were identified in both difference waves. The MMN latencies were measured at the trough. If there were two troughs in the difference waveform, one at the Ni latency and one later, the second one was taken as the MMN (Scherg et al., 1989). The amplitudes were evaluated based upon the difference between MMN onset and MMN trough. Frequency of occurrence, session and electrode effects on latency or amplitude values were tested using ANOVAs. Moreover, the morphologies of ERP evoked by the standard and deviant stimuli were examined. Ten periods of 50 ms long were defined. In each period, the responses to standard and deviant stimuli were compared as a fonction of âme. For each electrode, for

each temporal domain, the ERPs evoked by the standard stimuli or by the deviant ones were compared using an ANOVA analysis with subjects, condition, and occurrence as factors. The factor condition represented a value of 6 dimensions (3 electrodes * 2 sessions). Correlations between MMN latency or amplitude and speech recognition were tested using a Pearson coefficient.

All subjects perceived the differences between the stimuli. The data set consisted of responses from 100 to 150 deviant stimuli and from 484 to 729 standard stimuli.

Fig 1-a shows the averaged response to the standard stimulus for a representative subject. The classic P1-N1-P2 wave is obvions, with Ni latency at about 100 ms. Fig 1-b displays the grand mean averaged responses from the stimulation of electrode 13, 12, 10 and 8 as standard stimuli.

Statistical analysis (occurrence*electrode ANOVA on repeated measures, N=6) did not show any effect of occurrence or electrode on the N1 or P2 latencies. N1 occurs around 117 ms (SD=12) and P2 around 217 ms (SD=21).

Figure 2 shows the mean P IN I amplitude (a) and the mean N1P2 amplitude (b) for the standard and deviant stimuli. As no effect of the session was found, data relative to the same electrodes were gathered between sessions. The occurrence*electrode ANOVA on repeated measures on the averaged values demonstrates an effect of occurrence (F1=19.4, p1=0.007; F2=10.7, p2=0.022) and an effect of electrode (F1=4.4, p1=0.042) with interaction (F1=5.5, p1=0.024; F2=5.4, p2=0.026) on die PiN1 and N1P2 amplitudes, respectively. The post-hoc analysis, using the Student-Newman-Keuls test shows a difference between amplitude of deviants of pairs 2 and 3 vs. pair 1. For standard stimuli no differences were found. Mean PINI amplitude equals -4.3 gV (SD 1.3), and mean N1P2 amplitude equals 4.7 (SD 1.7 p.V).

The analysis of variance with condition and occurrence as factors indicates a condition effect, above all from 100 ms to 450 ms, an occurrence effect from 100 to 300 ms with a lower value for deviant stimuli in the 100-200 ms interval and a higher value in die 200-300 ms interval, and no interaction

between the condition and the occurrence. Figure 3 displays the mean ERP gathering all condition values for the standard and deviant stimuli by 50 ms periods.

Fig 4a shows the averaged responses to the standard stimulus (stimulation of electrode 13), the averaged responses to the deviant stimulus (stimulation of electrode 12), and the difference wave for a representative subject. The MMN deflection is obvious in the response to the deviant stimulus, overlapping the N1-P2 wave.

The paired t-tests did not show any differences between sessions on MMN latency (N=16, mean=145.4 ms, SD=20.4 for the first session; mean=134.4 ms, SD=26.1 for the second session) or amplitude (N=16, mean=-3.1 SD=2.4 for the first session; mean=-2.8, SD=1.0 for the second session). However, the test power was very low. One way ANOVAs on repeated measures did not show any differences between electrodes on the latency or amplitude values. The mean MMN latency is 139 ms (SD=23). Its amplitude equals -2.911V (SD=1.8). Fig 4b displays the mean MMN infra-session difference wave (N=6) for the three pairs of electrodes.

Fig 5a shows the averaged responses to die standard stimulus (stimulation of electrode 12), the averaged responses to the deviant stimulus (stimulation of electrode 12), and the difference wave for a representative subject. A negativity is obvions in this difference wave. One way ANOVAs on repeated measures did not show any differences between electrodes on the latency or amplitude values. The mean MMN latency of 142 ms (SD=22) and amplitude ofs -2.8 (SD=1.4) are die same as the MMN in the
Mea-session difference. Fig 5b displays the mean MMN intra-session difference wave (N=6) for the three pairs of electrodes.

Table III reports the speech tests results. The correlation analysis did not emphasize a relationship between MivLN amplitude or latency and speech performance, regardless what the speech test was. However, the low power of the correlation test did not allow to conclude to an absence of relationship.

The aim of the study was to characterize MMN recorded from electrical stimulation of Digisonic cochlear implant subjects. A multi-electrode implant consists of several electrodes spaced along the cochlea. By stimulating neural ganglia at more-or-less specific location through these implanted electrodes, some sensation of pitch may be restored. Activation of adjacent electrode can be discriminated behaviorally. The recording of MMN by stimulating two different electrodes may be related to the measure of frequency discrimination in normal-hearing subjects. Ponton and Don (1995), comparing responses to electrode pair stimulation in cochlear implant subjects and responses to tone burst stimulation in normal-hearing subjects, found earlier MMN waves with electrical stimulation (169 ms and 155 ms for 2 kHz and 1 kHz stimuli, respectively, vs. 114 ms and 89 ms for the basal and apical pairs, respectively) which may be explained by a more synchronized activation of neurons in the case of electrical stimulation. The stimulation of the apically located electrode pairs lead to larger responses than stimulation of the basally located electrode pairs. We found a mean MMN latency of about 140 ms for apical electrode stimulation essentially. The difference in latency with the Ponton and Don (1995) study can be due to the difference in the stimulation characteristics between the two cochlear implants: adjacent electrode pair in the Ponton and Don study, one array electrode vs. adjacent electrodes and common electrode in the Digisonic implant concerned in the present study. The latter mode of stimulation may

lead to a larger spread of current and a less synchronized activation. We found a shorter MMN latency than Kraus et al. (1993b). With 100 ms synthesized stimuli /da/ (standard) and /ta/ (deviant), they found a MMN latency of 220 ms, a duration of 121 ms, and an amplitude from onset to trough of -1.7 jtV. A similar MMN occurs when the /ta/-alone waveform was taken as standard reference. The difference between the two studies earlier and greater MMN in the present may be explained by the differences in stimuli used: phonemes in free field presentation vs. direct and localized electrode stimulation which may provide a more synchronized and replicable activation of the neurons. Indeed, stimulating bypassing

the speech processor allows precise and replicable activation of specific electrodes along the implant array. Moreover, the delay observed in case of speech discrimination may be the consequence of a longer speech processing compared to the non speech processing. The difference in MMN amplitude may also be due to the difference in the recording electrode position: FÉearlobe in the Kraus et al. (1993b) study, forehead/mastoid in this one.

Several studies showed that MMN peak latency increases as the standard deviant discrimination becomes more difficult (Sam et a1.,1985, Kakauranta et al., 1989, Scherg et al.,1989). The absence of electrode effect on MMN latency or amplitude suggests that the three tasks were as difficult, i.e., electrode 8 is not easier to discriminate from electrode 13 than electrodel2.

The evoked potentials recordings airns are also to try to predict speech recognition performance. Using the Digisonic cohlear implant, Gallégo et al. (1998) found a correlation between brainstem evoked potential wave III to wave V delay and speech recognition score (r=0.69; p<0.005) with a shorter interval linked with a higher recognition score. Groenen et al. (1997) found a relationship between phoneme recognition and middle latency responses. Makhdoum et al. (1997) demonstrated a positive correlation between cortical response (N1P2 amplitude) and speech performance in cochlear implant users, and a negative correlation with P2 latency. Kileny et al. (1997) investigated late and cognitive evoked potentials in children with cochlear implants. They studied the relationship between amplitude and latency of the cognitive response and speech recognition abilities. The latency tended to be shorter for the frequency contrast than for the loudness contrast which in turn tended to be shorter than for the speech contrast. In frequency, the discrimination showed shorter and stronger P3 and MMN that were associated with high sentence recognition scores. However, our study failed to show a relationship between latency or amplitude of MMN and speech recognition abilities. This might be due to the low power of the statistical test.

The authors wish to thank the Assistance Publique --Hôpitaux de Paris for their grant (PHRC n° 094034) and the MXM Laboratory for their fmancial support. The authors also wish to thank D. Moyse for helping with the statistics, S. Labassi for editing the manuscript, and the patients who volunteered for the experiments.

Beliaeff M, Dubus P, Leveau J-M, Repetto J-C, and Vincent P. Sound signal processing and stimulation coding of die Digisonic DX10 15-channel cochlear implant. In Advances in Cochlear Implants. Hochmair-Desoyer I.J. and hochmair E.S. (Eds), Manz, Wien, 1994:198-203.

Gallego S, Frachet, B, Micheyl C, Truy E, and Collet L. Cochlear implant performance and electrically evoked auditory brainstem response characteristics. Electroenceph. clin. Neurophysiol. 1998;108:521-525.

Groenen P.A.P, Makhdoum M, Van Den Brink J.L, Stollman M.H.P, Snik A.F.M, and van den Broek P. The relation between electric auditory brain stem and cognitive responses and speech perception in cochlear implant users. Acta Otolaryngol. (Stockh.), 1996;116:785-790.

Groenen P.A.P, Snik A.F.M, and van den Broek P. Electrically evoked auditory middle latency responses versus perception abilities in cochlear implant users. Audiology. 1997;36:83-97.

Herman B, and Thornton A. Electrically-evoked auditory brainstem responses in cochlear implanted subjects (abstr). Second International Cochlear Implant Symposium, Iowa City, IA 1992:57.

Kaukoranta E, Sams M, Hari R, Hâmâlâinen M, and Nââtânen R. (1989) Reactions of human auditory cortex to a change in tone duration. Hear. Res.. 1989;41:15-22.

Kileny P.R, Boerst A, and Zwolan T. Cognitive evoked potentials to speech and tonal stimuli in children with implants. Otolaryngol. Head Neck Surg. 1997;117:161-169.

Kraus N, McGee T, Micco A, Sharma A, Carrel T, and Nicot T. Mismatch negativity in school-age children to speech stimuli that are just perceptibly different. Electroenceph. clin. Neurophysiol. 1993b;88:123-130.

Kraus N, Micco A.G, Koch D.B, McGee T, Carrell T, Sharma A, Wiet R.J, and Weingarten C.Z. The mismatch negativity cortical evoked potential elicited by speech in cochlear-implant users. Hear. Res. 1993a;65:118-124.

Kraus N, McGee T, Carrell T, and Sharma A. Neurophysiologie bases of speech discrimination. Ear Hear. 1995b;16:19-37.

Kraus N, McGee T, Carrel T, King C, Tremblay K, and Nicol T. Central auditory system plasticity associated with speech discrimination training. J. Cogn. Neurosci., 1995b;7(1):25-32.

Kraus N, McGee T.J, and Koch D.B. Speech sound representation, perception, and plasticity : a neurophysiologie perspective. Audiology Neuro-Otology. 1998;3:168-182.

Makhdoum M.J, Groenen P. AP, Snik A. FM, and van den Broek P. Infra- and interindividual correlation between auditory evoked potentials and speech perception in cochlear implant users. Scand. Audiol. 1997;27:13-20.

Nââtânen R, Gaillard A.W.K, and Mântysalo S. Early selective attention effect on evoked potential reinterpreted. Acta Psychologica. 1978;42:313-329.

Nââtânen R., and Michie P.T. Early selective attention effects on the evoked potential. A critical review and reinterpretation. Biol. Psychol. 1979;8:81-136.

Nââtânen R., and Picton T. The NI wave of the human electric and magnetic response to sound : a review and an analysis of the component structure. Psychophysiology. 1987;24:375-425.

Oviatt D. and Kileny P. Auditory event-related potentials elicited from cochlear implant recipients and hearing subjects. Am. J. Audiol. 1991;1:48-55.

Pelizzone M, Kasper A, and Montandon P. Electrically evoked responses in cochlear implant patients. Audiology, 1989;28:230-238.

Picton T.W., Hillyard S.A., and Krausz HI., and Galambos R. Human auditory evoked potentials. I: evaluation of components. Electroenceph. clin. Neurophysiol. 1974;36:179-190.

Ponton C. W, and Don M The mismatch negativity in cochlear implant users. Ear Hear. 1995;16:131-146.

Sams M, Hâmâlâinen M, Antervo A, Kaukoranta E, Reinikainen K, and Han R. Cerebral neuromagnetic responses evoked by short auditory stimuli. Electroenceph. clin. Neurophysiol., 1985;61:254-266.

Scherg M, Vajsar J, and Picton T.W. A source analysis of the late human auditory evoked potentials. J.Cogn. Neurosci. 1989;1:336-355.

Tremblay K, Kraus N, Carrell T.D, and McGee T. Central auditory system plasticity : generalization to novel stimuli following training. J. Acoust. Soc. Am. 1997;102:3762-3773.

Table I- Age, etiology, deprivation duration, implantation duration and electrode tested for the subjects evaluated. Pulse duration were set to deliver stimuli at about 70% of the dynamic range.

Subject	Age	Etiology	Total deaf duration (yr)	Implantation duration (mo)	Electrode pairs tested [electrode: pulse duration (ils)]
JL	59	otosclerosis	4	8	13:33, 12:35, 10:31, 8:26
AN	40	meningitis	6	4	13:64, 12:66, 10:68, 8:68
HB	69	chronic otitis	2	21	13:22, 12:26, 10:29, 8:36
SO	71	otosclerosis	1	8	13:31,10:44, 8:38
MI	55	sudden deafness	1	6	13:16, 12:18, 10:18, 8:16
AZ	53	sudden, meningitis	7	12	13::14, 12:14, 10:16, 8:18
-SP	65	sudden deafness	13	28	13:24, 12:28
AC	59	progressive deafness	3	14	13:23, 12:25, 10:24, 8:27

Table III- Speech test performance for the six subjects included in the statistical analysis.

Subject	VCV	Words	Sentences	Lafon IC
ac	42	57	80	82
an	27	20	21	50
az	48	45	58	63
hb	65	41	81	75
il	46	49	84	45
mi	42	11	21	59
S s cl) p 15. â

standard : electrode 13 deviant : electrode 12 difference : deviant-standard

deviant 12 - standard 13 -- -- -- deviant 10 - standard 13 deviant 8 - standard 13

-standard: electrode 12 deviant: électrode 12 difference : deviant - standard

100 200 300

Time (ms)

Figure 1- a- Averaged response of the standard stimulus for a representative subject. The classic PI-NI - P2 wave is obvions, with N1 at about 100 ms. b- grand mean averaged responses from stimulation of electrode 13, 12, 10 and 8 as standard stimuli.

Figure 2- Mean P1N1 amplitude (a) and mean N1P2 amplitude (b) for standard and deviant stimuli in respect to electrode pairs.

Figure 3- Mean ERP values for standard and deviant stimuli by 50 ms periods. The stars indicate the signification level of the comparison for each interval. *: p<0.05, **: p<0.01, ***: p<0.001.

Figure 4-a- Averaged responses of the stimulation of electrode 12 as standard stimulus, as deviant stimulus, and difference wave for a representative subject. The MMN deflection is obvions in the response of the deviant stimulus, overlapping the N1-P2 wave. b- Grand mean MMN intra-session difference wave (N=6) for the three pairs of electrodes.

Figure 5-a- Averaged responses of the standard stimulus (stimulation of electrode 12), of the deviant stimulus (stimulation of electrode 12), and difference wave for a representative subject. A negativity is obvions in this difference wave. b- Mean MMN nitra-session difference wave (N=6) for the three pairs of electrodes.

Abbas PJ, Brown CJ. Electrically evoked auditory brainstem response: Growth of the response with current level. Hear Res 1991a 51:123-137

Abbas PJ, Brown CJ. Electrically evoked auditory brainstem response: Refractory properties and strength duration fonctions. Hear Res1991b 51:138-148.

Abbas PJ, Brown CJ. Electrically evoked brainstem potentials in cochlear implant patients with multi-electrode stimulation. Hear Res 1988 36:153-162

Allen JB, Hall JL, Jeng PS. Loudness grwth in 1/2 octave bands (LGOB) a procedure for the assessment of loudness. J Acous Soc Am 1990, 88 745-753

Beliaeff M, Dubus P, Leveau JM, Repetto JC, Vincent P. Sound processing and stimulation coding of Digisonic DX10 15-channel cochlear implant. Hochmair IN, ed. Advances in cochlear implant. Innsbruck: Verlag. 1994 198-203

Berger-Vachon C., Gallégo S., A. Morgon, Truy E.. Analytical Importance of the coding features for the discrimination of wovels in the cochlear implant signal. An Otol Rhinol Laryngol (1995), sup.166,104,9,2, 351353

Berger-Vachon C., Gallégo S., J.C. Bera, E. Arnoux, C. Kissac. A model of vowel representation using a cochlear implant. Proc. Inter. AMSE Symposium. Regio Calabria, (Italie), Sept 11-13 1997

Bertrand O, Perrin O, Pernier J. Evidence for a tonotopic organization of the auditory cortex observed with auditory evoked potential. Acta Otolaryngol (Sotckh) 1991, 491 116-123

Blamey PJ, Dooley GJ, Parisi ESP, Clark GM. Pitch comparison of acoustically and electrically evoked auditory sensation. Hear Res, 1996, 99 139-150

Bregman AS, Levitan R, Liao C. Fusion of auditory components. Effects of frequency of amplitude modulation. Perception and Psychophysics, 1990, 47, 68-73

Brightwell A, Rothera M, Conway M, Graham J. Evaluation of status of the auditory nerve: psychophysical test and

ABR. Eds RA Schindler & MM Merzenich Cochlear Implants Raven Press New York 1985 343-9

Brimacombe JA, Eisenberg LS. Tone decay in subjects with the single channel cochlear implant. Audiology 1984,

Brown CJ, Hughes ML, Lopez SM, Abbas PJ. Relationship between EABR thresholds and levels used to program the Clarion speech processor. Ann Otol Rhinol Laryngol, 1999, 108 50-57

Brown JB, Abbas PJ, Fryauf-Bertschy H, Kelsay D, Gantz BJ. Intraoperative and Postoperative Electrically Evoked Auditory Brain Stem Responses in Nucleus Cochlear Implant Users: Implications for the Fitting Process. Ear Hear 1994 15:168-176

Busby PA, Clark GM. Electrode discrimination by early-deafened cochlear implant patients. Audiology 1996 35:8- 22

Cazal Y, Pelizzone M, Kasper A, Montandon M. Indication of a relation between speech perception and temporal resolution for cochlear implantees. Ann Otol Rhinol Laryngol 1991 100:893-895

Cazal Y, Pelizzone M, Saudan O, Boex C. Amplitude modulation transfer fonctions associated with speech recognition for Ineraid cochlear implantees. Hochmair IN, ed. Advances in cochlear implant. Innsbruck: Verlag. 1994 321-325

Clark G, Shepherd R, Franz B, Dowell R, Tong Y et al. The histopathology of the human temporal bone and auditory central nervous system following cochlear implantation in patient. Acta Otolaryngol (Stockh) 1988 (suppl 448):165

Clark GM, Tong YC, Martin LFA. A multiple-charnel cochlear implant: an evaluation using closed-set spondaic words. J Laryngol 1981 95:461-464

Cohen LT, Busby PA, Whitford LA, Clark GM. Cochlear implant place psychophysics. Audiol Neurootol 1996, 1 265-277

de Sauvage RC, da Costa DL, Erre JP, Aran JM. Electrical and physiological changes during short-terni and chronic electrical stimulation of the normal cochlea. Hea Res 1997, 110 119-134

Deguine O. Implants cochléaires. Acquisition et controverses. Thèse de médecine, 1990

Dobie RA, Kimm J Brainstem responses to electrical stimulation of the cochlea. Arch Otolaryngol 1980, 106 573577

Don M, Eggermont JJ. Analyses of click-evoked brainstem potentials in man using high-pass noise masking. J Acoust Soc Am 1978 63(4):1084-1098

Donchin E., Ritter W., & McCallum C.W. (1978). Cognitive Psychophysiology : the endogenous components of the ERP. In E. Callaway, P.

Dorman MF, Loizou PC, Fitzke J, Tu Z. The recognition of sentences in noise by normal-hearing listeners using

simulations of cochlear implant signal processors with 6-20 channels. J Ascous Soc Am 1998, 104 3583-3585
Dorman MF, Smith M, Smith L, Parkin JL. The pitch of electrically presented sinusoids. J Acous Soc Am 1994

Doumèche P. L'accès au lexique chez le sujet porteur d'un implant cochléaire. Mémoire d'orthophonie, Paris, 1997 Dynes SBC, Delgutte B. Phase-locking of auditory-nerve discharges to sinusoïdal electrical stimulation of the cochlea. Hear Res 1992, 58 79-90

Eddington DK. Speech discrimination in deaf subjects with cochlear implants. J Acoust Soc Ain 1980 51:885-891 Eggermont JJ. Peripheral auditory adaptation and fatigue : a model oriented review. Hear Res 1985, 18 57-71

Fifer RC, Novak MA. Myogenic Influences on the Electrical Auditory Brainstem Response (EABR) in Humans.

Fitzgerald P. and Picton T.W. (1983) Event-related potentials recorded during the discrimination of improbable stimuli. Biological Psychology, 17, 241-276.

Friesen LM, Shannon RV, Slattery WH. Speech recognition in noise as fonction of the number of electrodes used in the speak, SAS and CIS speech processors. Confrence on Implantable Auditory Prostheses, Asilomar, August 29 -- September 3, 1999.

Frijns JHM, Snoo SL, ten Kate JH. Spatial selectivity in a rotationally symmetric model of the electrically stimulated cochlea. Hear Res 1996, 95 33-48

Fu QJ, Shannon RV. Effects of amplitude nonlinearity on phoneme recognition by cochlear implant users and normal-hearing listeners. J Ascous Soc Am 1998, 104 2570-2577

Gallégo S. Préservation de l'enveloppe temporelle pour la compression du signal de parole. IVe C F Audiologie 7-8 décembre 1998, Clermont-Ferrand. Sous- presse

Gallégo S. Utilisation de la psycho-acoustique pour le réglage de l'implant cochléaire Digisonic. Conférencié invité au IVe C F Audiologie 7-8 décembre 1998, Clermont-Ferrand. Sous-presse

Gallégo S., B Frachet, Truy E., L Collet. Modification des seuils en fonction des caractéristiques du patient implanté cochléaire. IVe C F Audiologie 7-8 décembre 1998, Clermont-Ferrand. Sous-presse

Gallégo S., B. Frachet, Truy E., Collet L.. Cochlear implant performance and electrically auditory brainstem response characteristics. Electroencephalography & clin neurophysiol. (1998), 108:521-525

Gallégo S., Ba Lê Luu, Berger-Vachon C.. Modelling of the electrical stimulation delivered by the Digisonic Multichannel cochlear implant. AMSE (1998), 39, 1, 39-54

Gallégo S., C. Micheyl, Berger-Vachon C., Truy E., A. Morgon, Collet L.. Ipsilateral ABR with cochlear implant. Acta Oto-Laryngologica. (Stockholm) (1996), 116, 228-233

Gallégo S., C. Micheyl. Intensity discrimination and auditory brainstem responses in cochlear implant and normalhearing subjects. Behaviorial Neuroscience (1998), 112, 4, 793-799

Gallégo S., Collet L., Berger-Vachon C.. A model of electrical stimulation delivered by the Digisonic cochlear implant. World Congress on Medical Physics and Biomedical Engineering, Nice, 14-19 september, 1997. J Int Federation for Medical & Biological Engineering, 35 (suppl), 1, 300

Gallégo S., Collet L., Berger-Vachon C.. Electrically auditory brainstem responses (EABR): contribution of a filter adapted to the auditory system. World Congress on Medical Physics and Biomedical Engineering, Nice, 14-19 september, 1997. J Int Federation for Medical & Biological Engineering, 35 (suppl), 1, 304

Gallégo S., Collet L.. Les méthodes objectives: Potentiels evoqués auditifs électriques précoces pré et post implantation, test d'intégrité. Dossier Entendre n° 7: La réhabilitation des surdités profondes par l'implant cochléaire, 33-40.

Gallégo S., E. Perrin, Berger-Vachon C., Truy E.. Recognition of vowels by cochlear implant using a Fuzzy logic. Proc. Inter. AMSE Symposium `Fuzzy Systems & Neural Networks'. Lyon (France), July 4-6 1994. (AMSE Press) 103-116

Gallégo S., Garnier S., Berger-Vachon C.. Traitement du signal de parole pour sourds-profonds: L'implant cochléaire. revue d'électricité et d'électronique (1997), 8, 50-53

Gallégo S., Garnier S., C. Micheyl, Truy E., A. Morgon, Collet L.. Loudness growth functions and EABR characteristics in Digisonic cochlear implant. Acta Otolaryngol (Stocldi) (1999)

Gallégo S., J. Durrant, Collet L., Berger-Vachon C.. Numeric time-variant filters adapted to the recording of electrically auditory brainstem responses (E-ABR). soumis

Gallégo S., J. Durrant, Truy E., Berger-Vachon C., Collet L.. Effect of stimulation intensity and intracochlear site on electrical auditory brainstem responses in human using a multichannel cochlear implant with a variable duration pulse. soumis

Gallégo S., M. Beliaeff, B. Frachet, M. Ouayoun, Berger-Vachon C., Collet L.. Long-term change in threshold and comfort levels and dynamics in Digisonic cochlear implant bearers. soumis

Gallégo S., M. Beliaeff, Collet L.. EABR with Digisonic cochlear implant: an indispensable objective method for fitting children. Digisonic News, number 2, June 1996

Gallégo S., M. Beliaeff. The long-terra evolution of cochlear implant thresholds. Digisonic News, number 4

Gallégo S., Truy E., A. Morgon, Berger-Vachon C., Collet L.. Les potentiels évoqués auditifs électriques précoces

(PEAEP) sur implant cochléaire: Caractérisation et applications cliniques. 4ème congrès français d'Acoustique.

Gallégo S., Truy E., A. Morgon, Collet L.. EABRS and surface potentials with a transcutaneous multielectrode cochlear implant. Acta Oto-Laryngologica. (Stockholm) (1997), 117(2), 164-168

Gallégo S., Truy E., Berger-Vachon C., Collet L.. Electrically auditory brainstem responses in cochlear implant assessment: possibility and interest. soumis

Gallégo S., Truy E., Berger-Vachon C., Collet L.. Electrically auditory brainstem responses in cochlear implant as évoqués auditifs électriques précoces (PEAEP) sur implant cochléaire: Caractérisation et applications cliniques. 4ème congrès français d'Acoustique. 14-18 avril 1997, Marseille, Vol 1, 463-466

Gallégo S., Truy E., Berger-Vachon C., Collet L.. Electrically auditory brainstem responses in cochlear implant assessment: possibility and interest. soumis

Garnier S., Gallégo S., Berger-Vachon C., A. Morgon, Collet L.. Application des techniques de codage de l'implant cochléaire à la prothèse auditive conventionnelle. 4ème congrès français d'Acoustique. 14-18 avril 1997, Marseille, Vol 1, 551-554

Garnier S., Gallégo S., Collet L.. Simulation acoustique du message delivré par l'implant cochléaire digisonic de MXM. Cahier de l'audition, 10, 6, 22-24

Garnier S., Gallégo S., V. Ziempfer, Berger-Vachon C.. Simulaton of an hearing aid based on cochlear implant coding. AMSE (1997), 37,1-2, 37-44

Gelis C. Bases techniques et principes d'application de la prothèse auditive. Ed Sauramps. 1993

Gorga MP, Kaminski JR, Beauchaine KA, Jesteadt W. Auditory brainstem responses to tone bursts in normally hearing subjects. J Speech Hear Res 1988 31:87-97

Groen PAP, Makhdoum M, van den Brink, Stollman MHP, Snik AFM, van den Broek. The relation between electric auditory brainstem and cognitive responses and speech perception in cochlear implant users. Acta otolaryngol (Stockh) 1996, 116 786-790

Groenen P, Snik A, van den Broek P. Electrically evoked auditory middle latency responses versus perception abilities in cochlear implant users. Audiology 1997, 36 83-97

Grônfors T. Novel methods of syntactic pattern recognition for peak detection of auditory brainstem responses. Thèse de physique. Kuopio, 1994

Gyo K, Yanagihara N. Electrically and acoustically evoked brainstem responses in guinea pig. Acta Otolaryngol (Stockh) 1980 90:25-31.

Hall RD. Estimation of surviving spiral ganglion cells in the deaf rat using the electrically evoked auditory brainstem

response. Hear Res 1990 of an hearing aid based on cochlear implant coding. AMSE (1997), 37,1-2, 37-44 Hellman R, Miskiewicz A, Scharf B. Loudness adaptation and excitation patterns : effects of frequency and level. J

Herman B, Thornton A. Electrically evoked auditory brainstem responses in cochlear implanted subjects. IInd International Cochlear implant symposium, Iowa city 1992

Hinojosa R, Seligsohn R, Lerner S. Ganglion cell counts in the cochleae of patients with normal audiograms. Acta Otolaryngol (Stockh) 1985 99:8-13

Honert van den C, Stypulkowski PH. Characterization of the electrically evoked auditory brainstem response (ABR) in cats and humans. Hear Res 1986 21:109-126

Honert van den C, Stypulkowski PH. Physiological properties of the electrically stimulated auditory nerve.II. Single fiber recording. Hear Res 1984 14:225-243

House WF, Berliner K, Crary W, Graham M, Luckey R, Norton N, Selters W, Tobin H, Urban J, Wexler M. Cochlear implants. An Otol Rhinol Laryngol 1976 85(suppl 27):1-93

Jewett DL, Williston JS. Auditory evoked far-fields averaged from the scalp of humans. Brain 1971 94:681-96 Kasper A, Pelizzone M, Montandon P. Electrically Evoked Auditory Brainstem Responses in Cochlear Implant Patients. ORL 1992 54:285-294

Kiang NYS et al. Discharge patterns of single fibers in cat's auditory nerve. MIT Res monograph No 35. MIT press, Cambridge, MA, 1965

Kiang NYS, Moxon EC. Physiological considerations in artificial stimulation of the inner ear. Ann Otol Rhinol Laryngol 1972 81:714-731

Kiang NYS. Stimulus coding in the auditory nerve and cochlear nucleus. Acta Oto Laryngol 1965 59:186-200 Kohlrausch A. Comment on 'Temporal modulation transfer functions in patients with cochlear imlants'. J Acous Soc Am, 1993, 93, 1649-1650

Killian MJP, Klis SFL, Smoorenburg GF. Adaptation in the compound action potential response of the guinea pig VIIIth nerve to electrical stimulation. Hear Res 1994, 81 66-82

Kraus N., McGee T., Carrel T., King C., Tremblay K., and Nicol T. (1995) Central auditory system plasticity associated with speech discrimination training. Journal of Cognitive Neuroscience, 7, 1, 25-32.

Kraus N., McGee T., Micco A., Sharma A., Carrel T., and Nicol T. (1993a) Mismatch negativity in school-age children to speech stimuli that are just perceptibly different. Electroencephalography and Clinical Neurophysiology, 88, 123-130.

Kraus N., McGee T.J., and Koch D.B. (1998) Speech sound representation, perception, and plasticity : a neurophysiologie perspective. Audiology Neuro-Otlogy, 3, 168-182.

Kraus N., Micco A.G., Koch D.B., McGee T., Carrell T., Sharma A., Wiet R.J., and Weingarten C.Z. (1993b) The mismatch negativity cortical evoked potential elicited by speech in cochlear-implant users. Hearing Research, 65,118-124.

Liberman MC. Auditory-nerve responses from cats raised in a low-noise chamber. J Acous Soc Am 1978 63:442455

Lina-Granade G. L'adaptation du système auditif périphérique chez l'humain. Thèse de Neurosciences, Lyon, 1996 Lorenzi C., Gallégo S., R.D. Patterson. Amplitude compression in cochlear implants artificially restricts the perception of temporal asymmetry. Brit J Audiol (1999)

Lorenzi C., Gallégo S., R.D. Patterson. Discrimination of temporal asymmetry in cochlear implantees. J Acoust Soc Am (1997), 102, 482-485

Lusted H, Shelton C, Simmons S. Comparison of electrode sites in electrical stimulation of the cochlea. Laryngoscope 1984 94:878-882

Mason S, Sheppard S, Garnham C, Lutman M, O'Donoghue, Gibbin K. Improving the relationship of intraoperative EABR threshold to T-level in young children receiving the Nucleus cochlear implant. ed. Advances in cochlear implant. Innsbruck: Verlag. 1994 44-49

Mc Dermott HJ, Mc Kay CM. Pitch ranking with nonsimultaneus dual-electrode electrical stimulation of the cochlea. J Acous Soc Am 1994, 96 155-162

Michelson RP. Electrical stimulation of human cochlear: A preliminary report. Arch Otolaryngol 1971 93(3):317 Miller CA, Abbas PJ, Brown CJ. Electrically evoked auditory brainstem response to stimulation of different sites in the cochlea. Hear Res 1993 66:130-42

Miller CA, Faulkner MJ, Pfingst BE. Functional responses from guinea pigs with cochlear implants. II Changes in electrophysiological and psychophysical measures over time. Hear Res 1995, 92 100-111

Miller CA, Woodruff KE, Pfingst BE. Functional responses from guinea pigs with cochlear implants. I Electrophysiological and psychophysical measures. Hear Res 1995, 92 85-99

Miskiewicz A, Scharf B, Hellman R, Meiselman C. Loudness adaptation at high frequencies. J Acous Soc Am 1993, 94 1281-1286

Moore BCJ, Glasberg BR. Gap detection with sinusoïds and noise in normal, impaired and electrically stimulated ears. J Acous Soc Am 1988 83:1093-1101

Moore JK. The human auditory brainstem as a generator of auditory evoked potentials. Hear Res 1987b 29:33-43 Moore JK. The human auditory brainstem: A comparative view. Hear Res 1987a 29:1-32

Morgon A, Aran JM, Collet L, Dauman R, Fraysse B, Freyss G, Pujol R, Sens A, Sterkers O, Pujol R. Le traitement de du son dans l'oreille interne. Pour la science, 1990, 154, 20-29

Moxon EC. Neural and mechanical responses to electric stimulation of cat's inner ear. Thesis. MIT. Cambridge, Mass, 1971

Nââtânen R. & Picton T. (1987) The N1 wave of the human electric and magnetic response to sound : a review and an analysis of the component structure. Psychophysiology 24, 375-425.

Nââtânen R., Gaillard A. and Mântysalo S. (1978) Early selective attention effect on evoked potential reinterpreted. Acta Psychologica 42, 313-329.

Nelson DA, Scmitz JL, Donaldson GS, Veimester NF, Javel E. Intensity discrimination as a fonction of stimulus level with electrical stimulation. J Acous Soc Am 1996 100:2393-2414

Oayoun MC. Traitement phonetique de la parole pour implants cochléaires. Thèse d'automatisme et traitement du signal, Paris, 1997

Patterson RD. The sound of a sinusoid : Spectral models. J Acous Soc Am 1994, 96 1409-1418

Patterson RD. The sound of a sinusoid : Time-interval models. J Acous Soc Am 1994, 96 1419-1428

Pfmgst B, Telman S, Sutton D. Operating ranges for cochlear implants. Mn Otol Rhinol Laryngol 1980 89(sup 66): 1-4

Pfingst B. Operating ranges and intensity psychophysics for cochlear implants. Arch Otolaryngol 1984 110:140-144 Pfmgst BE, Burnett PA, Sutton D. Intensity discrimination with cochlear implants. J Acous Soc Am 1993 94(3):1287-1294

Pfmgst BE, De Han DR,Holloway LA. Stimulus features affecting psychophysical detection thresholds for electrical

stimulation of the cochlea. I : Phase duration and stimulus duration. J Acous Soc Am 1991 90 1857-1866

Pfingst BE, Morris DJ, Miller AL. Effects of electrode configuration on threshold functions for electrical stimulation

Phillips AJ, Thornton ARD. Isochronic mapping of the auditory brainstem response : normative results. Brit J Audiol 1995, 29 335-346

Popelar J, Hartmann R, Syka J, Klinde R. Middle latency responses to electrical stimulation of the cochlea in cats. Hear Res 1995, 92 63-77

Ponton C.W., and Don M (1995) The mismatch negativity in cochlear implant users. Ear & Hearing, 16, 131-146. Ponton C.W., Don M., Waring M.D., Eggermont J.J., and Masuda A. (1993) Spatio-temporal source modeling of

evoked potentials to acoustic and cochlear implant stimulation. Electroencephalography and Clinical

Raab DH, Taub HA. Click intensity discrimination with and without background masking noise. J Acous Soc Am 1969, 46, 965-968

Raab DH, Taub HA. Fluctuations in N1 amplitude in relation to click-intensity discrimination. J Acous Soc Am 1969, 46, 969-978

Rohen JW, Yokochi C. Anatomie Humaine. Atlas photographique de l'anatomie systématique et topographique. Vigot, 1991

Rose JE, Hind JE, Anderson DJ, Brugge JF. Phase-locked responses to low frequency tones in single auditory nerve fibers of squirrel monkeys. J Neurophysiol 1967 30:769-793

Sachs MB, Abbas PJ. Rate versus level functions for auditory-nerve fibers in cat: tone burst stimuli. J Acous Soc Am 1974 56:1835-1847

Sachs MB, Young ED. Encoding a stady-state vowels in the auditory-nerve :Representation in terms of discharge rate. J Acous Soc Am 1979 66, 470-479

Shallop JK, Beiter AL, Goin DW, Mischke RE. Electrically evoked auditory brain stem responses (EABR) and middle latency responses (EMLR) obtained from patient with the nucleus multichannel cochlear implant. Ear Hear 1990, 11 5-15

Shallop JK, VanDyke L, Goin DW, Mischke RE. Prediction of behavioral threshold and confort values for Nucleus 22-channel implant patients from electrical auditory brain stem response test results. Ann Otol Rhinol Laryngol 1991 100:896-898

Shallop JK. Objective electrophysiological measures from cochlear implants patients. Ear Hear 1993 14:58-63 Shannon RV, Zeng FG, Kamath V, Wygonski J, Ekelid M. Speech recognition with primarily temporal cues. Science, 1995, 270, 303-304

Shannon RV. A model of threshold for pulsatile electrical stimulation of cochlear implants. Hear Res 1989 40:197204

Shannon RV. Detection of gap in sinusoïds and biphasic pulse trains by patients with cochlear implant. J Acous Soc Am 1989 85:2587-2592

Shannon RV. Multichannel electrical stimulation of the auditory nerve in man.I. Basic psychophysics. Hear Res 1983 11:157-189

Shannon RV. Temporal modulation transfer fonctions in patients with cochlear implants. J Acous Soc Am 1991 91:1256-1264

Simmons FB. Electrical stimulation of the auditory nerve in man. Arch Otolaryngol 1966 84:2-54

Smith DW, Finley CC, Honert C van den, Olszyk VB, Konrad KEM. Behavioral and electrophysiological responses to electrical stimulation in the cat.I. Absolute thresholds. Hear Res 1994 81:1-10

Smith L, Simmons FB. Estimating eighth nerve survival by electrical stimulation. Ann Otol Rhinol Laryngol 1983 92:19-23

Sohmer H, Feinmesser M. Cochlear action potentials recorded from the external ear in man. Ann Otol Rhinol Laryngol 1967 76:427-435

Spoendlin H, Schrott A. Analysis of the human auditory nerve. Hear Res 1989 43:25-38

Spoendlin H, Schrott A. The Spiral Ganglion and the Innervation of the Human Organ of Corti. Acta Otolaryngol (Stockh) 1988 105:403-410

Starr A, Brackman DE. Brainstem potentials evoked by electrical stimulation of the cochlea in human subjects. Ann Otol Rhinol Laryngol 1979 88:550-560

Stypulkowski PH, van den Honert C. Physiological properties of ellectrically stimulated auditory nerve. I Compound action potential recording. Hear Res 1984, 14 205-223

Tong YC, Clark GM. Absolute identification of electrical pulses rates and electrode positions by cochlear implant patients. J Acous Soc Am 1985 77(5):1881-1888

Townshend B, Coter N, van Compernolle D, White RL. Pitch perception by cochlear implant subjects. J Acous Soc Am 1987, 82 106-115

Tremblay K., Kraus N., Carrell T.D., and McGee T. (1997) Central auditory system plasticity : generalization to

novel stimuli following training. The Journal of the Acoustical Society of America, 102, 3762-3773.

Truy E., Gallégo S., Berger-Vachon C., A. Morgon. Multichannel cochlear implant in patients with ossified cochlea. Interest of the optimization of frequential selectivity of speech signal with Digisonic device. Proc. of IIIrd int. Symp. Transplants and Implants in Otology. Bordeaux (France), June 10-14 1995. (M. Portmann, P. Boudard, D. Portmann) 399-402

Truy E., Gallégo S., J.M. Chanal, Collet L., A. Morgon. Correlation between electrical ABR and perceptual thresholds in Digisonic cochlear implants users. Laryngoscope (1998), 108, 554-559

Truy E., Gallégo S., J.M. Chanal, Collet L., A. Morgon. Intérêt des potentiels évoqués auditifs électriques du tronc cérébral chez les patients porteurs de l'implant cochléaire Digisonic. Ann Otolaryngol Chir Cervicofac (1997), 114, 116-124

Truy E., JM Chanal, S Gallégo. Réglage des électrodes de l'enfant et de l'adulte. Rapport sur la prothèse auditive: Suppléance instrumentale de la surdité : les aides auditives (ed. SFORL), (1998), pp 361-372

Turner CW, Zwislocki JJ, Filion PR. Intensity discrimination determined with two paradigms in normal and hearingimpaired subjects. J Acous Soc Am 1989 86:109-115

Tyler RS, Parkinson AJ, Woodworth GG, Lowder MW, Gantz BJ. Performance over time of adult patients using the Inaired or Nucleus cochlear implant. J Acous Soc Am, 1997, 102, 508-522

Viemeister NF. Temporal modulation transfer fonctions based upon modulation thresholds. J Acous Soc Am, 1979, 66, 1364-1380

Wable J., S Gallégo, AM Jonas, I Roussillon, E Truy, Y Ormezzano, B Frachet, L Collet. Existe-t-il une relation entre les potentiels évoqués de latence tardive et la reconnaissance de la parole chez les implantés cochléaires? IVe C F Audiologie 7-8 décembre 1998, Clermont-Ferrand. Sous-presse

Wable J., S Gallégo, B Frachet. Adaptation chez les sujets porteurs d'un implant Digisonic. IVe C F Audiologie 7-8 décembre 1998, Clermont-Ferrand. Sous-presse

Wable J., T van Abbele, S Gallégo, Y Ormezzano, E Harboun-Cohen, M Papermann, I Roussillon, B Frachet. Evaluation des capacités de discrimination des implantés cochléaires à l'aide des potentiels évoqués de latence tartive. Sous-presse

Wable J., T. van Abbeele, Gallégo S., B. Frachet. Mismatch negativity: a tool for the assessment of stimuli discrimination in cochlear implant subjects. Accepté dans EEG Journal.

Waring MD. Auditory brain-stem responses by electrical stimulation of the cochlear nucleus in human subjects. Electroenceph clin Neurophysiol 1995 96:338-47

Waring MD. Electrically evoked auditory brainstem response monotoring of auditory brainstem implant integrity during facial nerve tumor surgery. Laryngoscope 1992 102:1293-5

Waring MD. Properties of auditory brainstem responses evoked by intra-operative stimulation of the cochlear nucleus in human subjects. Electroenceph clin Neurophysiol 1996 100 538-548

Zeng FG, Shannon RV.Loudness coding mechanisms inferred from electrical stimulation of the auditory system. Science 1994, 264 564-566

Zeng FG, Shannon RV.Loudness Growht in electrical stimulation. ed. Advances in cochlear implant. Innsbruck: Verlag. 1994 339-341

Contrainte Psycho-Physiques et Electrophysiologiques sur le codage de la stimulation électrique chez les sujets porteurs d'un implant cochléaire

- Article 22 :

MISTMATCH NEGATIVITY : A TOOL FOR THE ASSESSMENT OF STIMULI DISCRIMINATION IN
COCHLEAR IMPLANT SUBJECTS

Contrainte Psycho-Physiques et Electrophysiologiques sur le codage de la stimulation électrique chez les sujets porteurs d'un implant cochléaire

- Article 22 :

MISTMATCH NEGATIVITY : A TOOL FOR THE ASSESSMENT OF STIMULI DISCRIMINATION INCOCHLEAR IMPLANT SUBJECTS

MISTMATCH NEGATIVITY : A TOOL FOR THE ASSESSMENT OF STIMULI DISCRIMINATION IN
COCHLEAR IMPLANT SUBJECTS