Speech and language development following ... - ResearchGate

C. Ouellet, H. Cohen / Journal of Neurolinguistics 12 (1999) 271±288 273Language development appears to be based on relatively plastic neural systemsthat are also used for other cognitive and perceptual functions [4]. But childrenand adults do not necessarily use the same neural resources for languageperception and production and some parts of the brain may be more active incertain kinds of linguistic activities over time. Locke [37] assigns early vocallearning and utterance acquisition to the right hemisphere whereas, in oldersubjects, the left hemisphere is dominant for everything related to lexicalcomprehension, expression, syntax and grammar tasks. One follow-up study hasshown that the linguistic abilities of a left-hemispherectomized child were similarto those of language-impaired children whereas the linguistic competencies of aright-hemispherectomized child resembled those of language-normal children [75].In the same way, school-age children with left hemisphere lesions show morediculties with language than those with right hemisphere lesions, althoughproblems in language development may occur in both groups. These resultsprovide indirect support for innate specialization and plasticity as well as for theinvolvement of the right hemisphere in language acquisition and verbal cognition[49].Experience may also in¯uence cerebral organization and activity. Dehaene et al.[17] found some anatomical variability in the cortical representation of ®rst andsecond languages. Subjects who listened to stories in their ®rst language showedactivation of the left temporal lobe, especially in the areas along the left superiortemporal sulcus, whereas those who listened to stories in their second languageshowed activity in varying left and right temporal and frontal areas, sometimesrestricted to right hemisphere regions.The central auditory system may also experience a functional reorganizationfollowing changes in auditory stimuli, leading to linguistic improvement [70].Volumetric measurements of the planum temporale, contained in the perisylvianarea, which has been implicated in language development, have revealed that thisarea is already larger on the left than on the right side in the fetal brain.Following auditory deprivation, which results in inactivation of the neurolinguisticmechanisms, a compensatory hypertrophy of the homologous right hemispherestructures may develop as a result of a general neuromaturational delay. The righthemisphere would then control linguistic parameters that were previously underthe left hemisphere's domination. There is a functional shift to intact brainstructures at that time. According to Locke [37], this adaptive but unusual brainorganization produces a functional but imperfect command of language. Pontonet al. [61] suggest instead that the auditory system does not mature withoutstimulation. They showed that the maturational processes of the cortical auditorysystem, which do not progress during a period of deafness, resume after acousticstimulation is reintroduced. However, Truy et al. [80] found that the ascendingauditory pathways remain operational long after prelingual deafness and that theauditory cortex can be activated by electrical stimulations of the cochlea evenwithout perception of environmental sounds. In their study, subjects showedincreased auditory cortex activity during electrical cochlear stimulation.

3. Cochlear implantsC. Ouellet, H. Cohen / Journal of Neurolinguistics 12 (1999) 271±288 275Cochlear implants are computerized devices that restore speci®c functions to thecochlea. They are designed for patients with bilateral profound to total deafnesswho receive little or no bene®t from sound ampli®cation [10]. They are also usefulfor the rehabilitation of patients with residual hearing and some speechunderstanding [67]. These electronic devices enable the stimulation of thevestibulocochlear nerve via the electrical current they generate from the acousticvibrations [81]. This electrical stimulation of undamaged ®bres of the cochlearnerve can restore hearing when all hair cell function is lost and there is nopossibility of speech discrimination with hearing aids. The device consists of (1) amicrophone that picks up and sends auditory stimuli to (2) an external processorthat transforms the mechanical acoustic wave into an electric signal and (3) anelectrode array implanted near the auditory nerve [46]. A system of induction coilsallows for the electrical connection across the skin between the implantedelectrodes and the processor. Fig. 1 is a schematic representation of the cochlearimplant and auditory system.Cochlear implants may be single- or multichannel. The latter enhance lipreadingand permit discrimination of speech without vision in the majority ofcases [24]. A comparison of implant systems showed that the multichannelprostheses permitted correct transmission of a larger number of acoustic stimuliand enabled greater speech reading abilities as well as open-set speech recognition.The implant systems most used by deaf patients nowadays are the Nucleusdevice, the Ineraid and the Clarion system. The ®rst two are second-generationimplants whereas the Clarion device is a more modern, third-generation system.The 22-channel Nucleus implant is the only intracochlear device licensed for use inchildren by the American Food and Drug Administration [23]. Children withmeningitis or cochlear ossi®cation who become deaf between the ages of 18 and23 months can be implanted with the Clarion system. This third-generation device,introduced in 1993, contains 16 electrodes arranged into 8 bipolar pairs thatoperate simultaneously or sequentially. It is also the ®rst device to o€er a choiceof processing strategies in one processor [11]. Moreover, Tyler and Summer®eld[86] found better performance in word identi®cation with a Clarion group of deafpatients than with Ineraid and Nucleus groups; the latter two groups performed ata comparable level. Other devices have also been developed (e.g. the AustrianMed-El multichannel prostheses and the Digisonic and Laura multichanneldevices developed in France and Belgium, respectively) which can apparentlyenhance speech understanding without lip-reading [11].The external speech processor hardware and software of a cochlear implant canbe adjusted to suit an implant user's preferred speech-processing strategies. Thesedi€erences in usage of an identical device may be due to di€erences in the etiologyof the patients' deafness or in the way their central nervous system originallylearned to decode the cues necessary to discriminate speech sounds [38]. Speechcoding strategies are thus parameters of implant systems that may a€ect thelinguistic performance of both adult and child users. The single-channel cochlear

C. Ouellet, H. Cohen / Journal of Neurolinguistics 12 (1999) 271±288 277system and language acquisition development [34] and the negative correlationbetween age at onset of deafness and the development of speech perception,speech production and language competence following an implantation, it is clearthat younger children can derive signi®cant bene®ts from an implant [44]. Despiteobjections concerning biosafety problems such as head and temporal bone growth,otitis media, device extrusion or migration and the diculty of estimating theresidual hearing, or any other handicap, of young patients [34], clinical experienceand laboratory data strongly suggest that cochlear implantation is possible beforethe age of two [25]. Implantation may also result in better speech perception andoverall linguistic performance in children as young as 16 months [58], probablybecause it reduces the language development delay.Although there are no age restrictions in terms of onset of deafness, the issue ofan upper age limit for this surgical operation is often debated. It has been arguedthat the decision to implant should be based solely on whether the patient's healthallows such a surgical intervention [44]. It has been shown that there are nosigni®cant di€erences in performance on closed-set tests of speech perceptionability between prelingually deafened children implanted before or after the age of®ve Ð even though the former performed better on open-set word recognition[19]. However, prelingually deaf children implanted after 12 years of age, whohave practiced and established a manual communication system, may show alower response following implantation. Although the procedure should not bedenied, Tyler et al. [84] do not recommend it for such patients.The criteria for implantation candidacy have relaxed since the establishment ofthe ®rst national clinical trial of single-channel cochlear implants in 1979 [5].Initially, only deaf patients with bilateral profound sensorineural hearing loss whowere not able to perform open-set listening were considered for such an operation.Until 1991, no patients performing over 20% correct with conventionalampli®cation on open-set tests were implanted [91]. Recently, the US Food andDrug Administration approved the candidacy of hearing-impaired adults withbinaural open-set sentence recognition scores no greater than 30% correct for theNucleus device [11]. According to Yaremko and Gibson [91], good hearing aidusers obtaining correct scores of between 30% and 50% on open-set tests shouldnot be automatically rejected. However, patients must be aware that any residualhearing in the implanted ear will likely be destroyed by the electrode insertion,thus precluding future use of a hearing aid in that ear.Patient selection is ®nally determined through audiological, medical andpsychological assessments. During the audiological evaluation, the unaided andaided thresholds using conventional ampli®cation are established [44], giving ameasure of the functional hearing aid bene®t and allowing one to choose the earto be implanted - which is often the most a€ected one. The medical examinationincludes the otological history, the physical examination and the radiologicalevaluation of the cochlea. The etiology of the deafness may be determined in thisway. An otologically stable condition must be present to consider the feasibility ofthis surgical operation, which means an intact tympanic membrane and theabsence of infection or otitis media. Medical or surgical treatment prior to the

278C. Ouellet, H. Cohen / Journal of Neurolinguistics 12 (1999) 271±288intervention may be required to meet these conditions. The cochlea is alsoexamined to detect any malformation or intracochlear ossi®cation. Finally,exclusionary factors may be identi®ed in the psychological assessment, such asundetected psychosis, organic brain dysfunction or mental retardation.5. Mediating factorsSeveral factors appear to in¯uence the bene®ts of a cochlear implantation andhelp explain, alone or in combination, the large between-subject di€erences inimplant outcome and the variance in patients' linguistic improvement. Amadori etal. [1] de®ned a number of predictors concerning a broad range of linguisticperformances: (1) age at onset of deafness, with postlingual patients being moreecient than prelingual ones; (2) duration of deafness, with better results beingassociated with a shorter period of deafness; and (3) length of electrode insertionand activation, with poorer performance usually being associated with fewer than10 active electrodes. For other researchers, the most important predictive factorsare auditory nerve survival [44] and responsiveness of the central nervous system[86].A moderate correlation between speech recognition performance in adults andelectrical thresholds, dynamic ranges and the number of active electrodes has beennoted [20,28], whereas patients' willingness and motivation were also found to bestrongly associated with speech understanding [20,30]. Visual informationprocessing skills, knowledge of nonverbal communication strategies and activemanagement of one's healthcare are further factors, alone or in combination, thatcould account for the variability in postoperative scores [21]. Finally, there isapparently no relationship between IQ alone and implant outcome.It might be expected that post-implant linguistic abilities would depend uponthe age at which someone went deaf. However, Osberger et al. [55] did not ®nddi€erences in speech perception performance between children born deaf(congenitally deafened) and those deafened before the age of 3 (prelinguallydeafened children). They only ®nd signi®cantly better skills on tests of stresspattern, closed- and open-set discrimination in children deafened after the age of5. In contrast to these results, Nikolopoulos et al. [50] found lower scores inprelingually deaf children compared to congenitally deaf children on a scaleassessing the developing use of post-implant audition. Ito et al. [27] demonstrateda delayed speech comprehension performance in prelingually deaf patientscompared with postlingually deaf ones; nevertheless, the former group alsoprogress in the ®rst years after implantation, at a slower but still continuous rate[33].The age at which patients are implanted is also a critical variable. Prelinguallydeafened candidates implanted in adolescence or adulthood do not score abovechance levels on word and sentence identi®cation tests without lip-reading. Thismay be due to their lifestyle and manual communication experience, to social andcultural in¯uences and/or to the e€ects of longer auditory deprivation since birth

C. Ouellet, H. Cohen / Journal of Neurolinguistics 12 (1999) 271±288 279[8,14]. There may also be a trend towards non-use of the device in patientsimplanted during adolescence [46]. However, Summer®eld and Marshall [76] failedto replicate this association between age at implantation and performance.Duration of deafness has been found to have the most robust association withperipheral (the number of ganglion cells) and central determinants (responsivenessof the nervous system, potential for relearning and memory for sounds of speech)of good performance with the device [86]. Subjects with a shorter duration ofauditory deprivation tended to perform better on tests of speech perception thanthose with longer periods of deafness [72,73]. However, this factor has been foundto account for only about 20% of the speech understanding variance [86].Finally, experience with implant usage will also determine the course ofimprovement of response to the device over time. Implant performance is usuallymeasured between one week and one month after device activation Ð this is thetime required to program the processor optimally [86]. Speech perception maysigni®cantly improve after 6, 12 and 24 months of implant use [89]. Recognitionperformance generally increases over the ®rst 9 months of implant experience andabout half of this improvement occurs within one month of implantation. Thetime frame for improvements in performance with second-generation implantsystems may extend over 2 or 3 years, with large individual di€erences observed inthe pattern of performance evolution [86]. For instance, data suggest thatimprovements in closed-set recognition do not occur before 1 year of implant usein prelingually deafened children; open-set speech recognition takes even longer[18,45,88] because of the complex linguistic and auditory processes involved.However, Staller et al. [74] found signi®cant improvements in speech perceptionskills after only 6 months of device experience. As for speech production, it mayincrease throughout the ®rst 4 months but progress slows down at 1 year.However, the possible rapid improvements from day 1 to days 30 and 120 in aprelingually deaf group suggest that cochlear implants allow immediate bene®ts inspeech production [79] Ð but these discrete changes do not increase the listener'scapacity to understand an implanted child's speech until after about 2.5 yr ormore of device use [64].6. Linguistic consequences of cochlear implantationCochlear implants enable di€erent degrees of improvement for deaf patients inthe areas of speech and language perception, production and comprehension,depending upon the extent of their hearing loss and other variables. These areasinclude several subskills, which develop in a relatively hierarchical order. Althoughthe immediate response following activation of the device is not always clear,subsequent progress in auditory discrimination is soon evident, with voweldiscrimination reaching 100% in 8 months in certain circumstances. Articulationand intonation also improve, as well as reception of sounds from the environment[51]. Gains in receptive and expressive language may exceed those predicted frommaturation alone in children after 12 months of device use, with a language

280C. Ouellet, H. Cohen / Journal of Neurolinguistics 12 (1999) 271±288development rate similar to that observed in normal hearing children [65]. Thepatient's response therefore progresses from a phase of sound detection, to speechdiscrimination, to the ability to repeat fragments of speech and ®nally to trueunderstanding of speech [90]. Cochlear implants can help in improving vocabularyacquisition for prelingually deaf subjects, as demonstrated in a study whereperformance at various postoperative intervals was higher than mean preoperativeperformance. Furthermore, the postoperative rate of improvement was alsogreater than the preoperative rate [15]. These implant devices can improvecommunication ability in most adults as well [52] and may also prove to be anecient auditory substitute for deaf±blind people, enabling telephonicconversation [2].Surgical implantation can also help in the evaluation of pitch in musicalintervals, in both interval estimation and interval production, but over a limitedrange of about two octaves. This suggests that, as the interval increases, thejudgment of the implanted subjects diverged from that of normal-hearingindividuals [41].Cochlear implants can also give access to auditory perceptual informationotherwise unavailable. Speech perception is enhanced by increasing the auditorysignal. Research results on speech perception tests, one year followingimplantation, were signi®cantly higher than pre-implantation observations in amajority of prelingually deaf children, even when preoperative levels suggested alimited verbal ability. Pattern perception, spondee and monosyllable identi®cationall increased. Pattern perception appeared to be the easiest task whereasmonosyllable identi®cation was the most dicult [79]. Miyamoto et al. [45] alsoshowed a pattern of word identi®cation development in their implanted children,with no great changes in performance after 6 months of experience; the largestperformance increase occurred one year after the operation, followed by steadyimprovement. Usually, the least dicult tests assess identi®cation ofenvironmental sounds and recognition of the prosodic characteristics of speech(e.g. temporal or intonation patterns) and the most dicult tests are those ofword or sentence recognition in an open-set condition. This type of speechrecognition, in auditory-only conditions, is the ultimate goal of the cochlearimplant procedure [44].Geers and Moog [22] proposed a hierarchy of speech perception abilitiesfollowing implantation: (1) no pattern perception, (2) consistent patternperception, (3) inconsistent word identi®cation, (4) consistent word identi®cationand (5) open-set word recognition. Using this classi®cation system, Staller et al.[72] found that the percentage of children reaching categories 3, 4 and 5 (i.e.closed- or open-set recognition) increased from 12% to 80% after the operation,with about 50% of their subjects showing open-set speech recognition. In anotherstudy, 100% of phoneme detection (a ceiling performance) was achieved threemonths after implantation in children with prelingual deafness, whereas bothclosed-set word and sentence identi®cation and open-set recognition increasedgradually, reaching 100% and 80%, respectively, by 48 months Ð with progresson the latter task not observed until 12 months after implantation [48]. However,

C. Ouellet, H. Cohen / Journal of Neurolinguistics 12 (1999) 271±288 281Uziel et al. [87] demonstrated that modi®ed open-set recognition was quite evident12 months following the implantation and got even better three years later.Regardless of the percentage of success, open-set discrimination always appearspossible with multichannel implants in most children born deaf or with acquireddeafness, even in hearing-alone conditions [23]. This increased response to soundsin everyday life makes children more alert to interactions with their environment.Three months after wearing the device, children can respond to their names up to63% of the time [53].Although there is generally some improvement in speech perception until 4 or 5years post-implantation, some subjects may, on occasion, show decreased speechperception performance over time, apparently due to a cognitive regressionassociated with age [85]. As was suggested earlier, postoperative performanceappears in¯uenced by the level of preoperative linguistic abilities. In e€ect,patients possessing some preoperative open-set recognition abilities obtainedsigni®cantly higher scores on all recognition measures, at 12 months postimplantation,whereas those with no open-set speech recognition skills before theoperation improved on only half of the measures in the same post-implant period[92]. Speech identi®cation also varies according to word frequency, lexical densityand word length. Lexically easy words (high frequency with few neighbors) arebetter identi®ed than more dicult words (low frequency with many neighbors);word recognition is also better for polysyllabic than monosyllabic stimuli [29].The primary role of cochlear implants is to enable speech perception. Animportant secondary role is to permit speech production and help patients acquireand produce consonant and vowel features which are dicult for individuals withprofound hearing loss (e.g. high vowels, diphthongs, alveolar consonants andfricatives [54]. Language development in implanted prelingually deaf children maybe signi®cantly faster than predictions based only on maturation of unimplantedpeers would suggest. At the 12-month postoperative interval, expressive languagescores have been shown to be higher than the corresponding scores predictedbased on non-operated peers Ð this e€ect was not seen at the 6-month interval.Although implanted children were delayed compared to normal-hearing subjectsat each interval tested, their rate of language growth matched that of hearingcontrols. The gains made by implanted children in expressive language weresimilar to those expected from hearing children and superior to those expectedfrom unimplanted deaf children, at each testing interval from 6 months to 2.5years after implantation. There is, however, signi®cant inter-subject variability inlinguistic abilities following the operation, with some patients reaching nearnormallanguage levels, whereas others remain delayed and show a wide gapbetween linguistic age and chronological age [47].Implant users may exceed their preoperative performance for both intelligibilityand articulation, after experience with a device for from 1 to 4.5 years. Theseimprovements occur for front, middle and back consonants, for stops, fricativesand glides and for voiceless and voiced consonants [16]. The intelligibility ofprelingually deaf children's speech may increase steadily over time, becomingsigni®cantly better than the preoperative performance level after only 6 months.

282C. Ouellet, H. Cohen / Journal of Neurolinguistics 12 (1999) 271±288However, despite some positive changes in the discrete elements of speech (e.g.vowel and consonant production), the improvement remains rather weak for the®rst 2 post-implant years and gradually reaches 40% after 3.5 years of implantexperience. Open-set speech intelligibility is the most dicult measure of speechproduction to master [64]. Mondain et al. [48], however, showed that the averagespeech intelligibility for prelingually deaf children, after 4 years of experience withthe implanted device, reached 74% correct. Te et al. [79] found a di€erent patternof improvement in prelingually deaf children, with immediate correct speechscores as early as the ®rst day of implant use. Speech production then improvedquickly for the ®rst 4 months, with rapid improvement from day 1 to days 30 and120, providing evidence for immediate gains in speech production with cochlearimplants. Vowel production was the easiest task to master and word-patternrecognition and consonant voicing tasks were of intermediate diculty. Thehardest skills to achieve were consonant placing and manner of consonantproduction. Speech production may reach a plateau by 1.5 years followingimplantation with single-electrode devices, but no plateau has yet been observedwith the Nucleus multichannel device after 2 or more years of use [45].Children who gain some speech intelligibility, regardless of their degree ofimprovement, do not show any degradation in their speech production abilitiesafter switching o€ their cochlear implant for several hours. No di€erence in vowelheight, vowel place, initial consonant place, initial consonant voicing, or ®nalconsonant voicing was found between the device-on and -o€ conditions in theseimplanted children. When the device was turned on, there was sometimes atendency for nasalization of vowels and inappropriate aspiration of consonants,suggesting an e€ort to increase proprioceptive feedback [83]. After at least 2 yearsof implant use, prelingually deaf children can produce consonants varying on thefeature of place of articulation with greater accuracy than those that contrast onvoicing, duration and frication. Moreover, implanted subjects who were likely todiscriminate place of articulation, nasality and voicing features in audition-onlyconditions also produced these features more correctly [82]. However, goodperceivers are not always good producers [60].Finally, a case study reported by Robinshaw [66] showed signi®cantimprovements in the ability to imitate prosody and speech sounds following theimplantation procedure. In this particular case, speech production occurredshortly before word comprehension and the patient followed a pattern ofdevelopment predicted by Ling 1 [35,36]. The pattern and timing of spoken wordacquisition was delayed but nevertheless similar to that of normal-hearing controlsof the same hearing age. Soon after the switch-on, the subject's phonetic and1 This order, proposed by Ling [35,36], suggests that speech development in prelingually deaf childrenwith cochlear implants follows a succession of seven stages, from lower to higher skills: (1) vocalizationfreely and on demand, (2) suprasegmental patterns, (3) all vowels and diphthongs with voice control,(4) production of consonants by manner of articulation with all vowels, (5) consonants by place withmost vowels, (6) consonants by voicing with most vowels and (7) initial and ®nal blends (intelligiblespeech and natural voice patterns), with this ®nal level reached after 2 yr of implant experience.

C. Ouellet, H. Cohen / Journal of Neurolinguistics 12 (1999) 271±288 283phonological skills developed and phonetic/articulatory skills emerged beforeextending to everyday speech. The phonological level followed the phonetic one.This is in agreement with Miller [42], who found that the impairment caused byprelingual deafness may be restricted to the phonological aspects of language.7. Psychosocial impactsTait [77] reported an increase in eye contact and vocal turn-taking, as well as adecrease in gesture in 10 children after 12 months of cochlear implant experience.This enhancement of attention and involvement apparently permitted better verbalcommunication. Tait and Lutman [78] also found a propensity towards a vocal/auditory communication style in implantees. However, despite these changes incommunication modality, implanted children may continue to use signs incombination with vocalizations to communicate [62].Cochlear implants can also in¯uence the social behavior and social competenceof hearing-impaired people, who may lack peer acceptance and have lessdeveloped social abilities. Although some data suggest that young implantees maysometimes remain immature in their social interactions with hearing peers [31],other results show that cochlear implants improve interpersonal communicationskills and social con®dence and also reduce the user's social anxiety [26]. Severalpositive impacts of cochlear implants on the behavior of deaf children, whofrequently have behavior problems and are often impulsive and rigid [69], havebeen noted [13,40]. These improvements, however, may not always be maintainedover time and systematic investigations are still needed [62]. Good performers withcochlear implants will still encounter some linguistic diculties a€ecting theirinterpersonal interactions [46], despite changes in their communication mode.Cochlear implantation also has varied in¯uences on how parents communicatewith their implanted children. Six months after the operation, some mothers mayno longer use signs with their implanted child ([62], but see [31]). No matter how,cochlear implants do a€ect communication practices and not alwayssystematically. Nevertheless, these implants favor a variety of communicationstrategies and thus an enhanced mutual understanding. However, they have notbeen found to be e€ective in reducing parental anxiety. Parenting stress does notnecessarily decrease postoperatively Ð it may even increase. This may be due tounrealized expectations, the necessity of parental involvement in auralrehabilitation and restrictions in the pursuit of the parent's personal activities [63].8. RehabilitationSupport from home and school, training, (re)habilitation and education areessential factors that determine linguistic improvement [11] and permit theachievement of adequate phonetic and phonological competencies. Animplantation should be performed only if the cochlear implant center can o€er

284C. Ouellet, H. Cohen / Journal of Neurolinguistics 12 (1999) 271±288multidisciplinary team support before the operation, as well as immediate andintensive speech rehabilitation in which both parents and teachers must cooperate[6]. These education and (re)habilitation services, which are important for adultsbut critical for children, should include technical and pedagogical training [32].This rehabilitation may take months [24] and lasts longer for prelingually thanpostlingually deaf patients [27]. Individual sessions of about 1.5 h at regular preandpostoperative intervals may be one way to provide language habilitation andeducational training [15]. Ling [35,36], however, advocates three-minute sessions,several times a day, to reach a level of automatic speech, thus permitting thetransfer of acquired speech patterns to everyday situations. No matter how thesetraining sessions are provided to patients, the techniques must be adapted tochildren and made available to parents or other individuals supporting youngcochlear implant users.To develop hearing and speech abilities, patients must receive adequatestimulation. The habilitation should focus on the use of audition to optimizelanguage development, including the improvement of speech and languageperception and production skills. Parents are encouraged to preferentially useaudition in their interactions with children [15] and guide them into auditoryverbaleducation and linguistic interactions on a daily basis [7]. Finally, either oral(speech plus listening) or total (signs plus speech and listening) modes ofcommunication may be applied.References[1] Amadori M, Pantano N, Cestaro A, Babighian G, et al. Considerations on the rehabilitation ofthe hearing in cochlear implant patients. Acta Otorhinolaryngologica Italia 1996;16:324±33.[2] Arauz SL, Aronson L, Mastroianni-Pinto SN, Preti MC, Pallante SA, Estienne PA, Ortega M.Multichannel cochlear implant in a deaf±blind patient. Audiology 1997;36:109±16.[3] Barthelemy P. The very young deaf child and his body: The relationship between the body withdevelopment of cognition, language, motor skills. Revue de Laryngologie Otologie Rhinologie1996;117:277±83.[4] Bates E. Language development. Current Opinions in Neurobiology 1992;2:180±5.[5] Berliner KI. Selection of cochlear implant patients. In: Schindler RA, Merzenich MM, editors.Cochlear Implants. New York: Raven Press, 1985.[6] Bertram B. Pedagogic aspects of rehabilitation of children with a cochlear implant. Report fromHannover Cochlear Implant Center. Wiener Medizinische Wochenschrift 1994;144:3±7.[7] Bertram B, Pad D. Importance of auditory-verbal education and parents' participation aftercochlear implantation of very young children. Annals of Otology, Rhinology and Laryngology1995;166(Supplement):97±100.[8] Chute PM. Cochlear implants in adolescents. Advances in Otorhinolaryngology 1993;48:210±5.[9] Clark G, Blamey PJ, Brown AM, Gusby PA, Dowell RC, Franz BK, Pyman BC, Shepherd RK,Tong YC, Webb RL, et al. The University of Melbourne-nucleus multi-electrode cochlear implant.Advances in Otology, Rhinology and Laryngology 1987;38:1±181.[10] Cohen NL. Cochlear implants. In: Bluestone CD, Stool SE, editors. Atlas of PediatricOtolaryngology, 1995.[11] Cohen NL, Waltzman SB. Cochlear implants: an overview and update. Otolaryngology Ð Headand Neck Surgery 1995;116:146±52.[12] Cohen NL, Waltzman SB, Roland Jr. JT, Bromberg B, Cambron N, Gibbs L, Parkinson W,

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