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Communication Development in Children Who Receive the Cochlear Implant Younger than 12 Months: Risks versus Benefits

Dettman, Shani J.; Pinder, Darren; Briggs, Robert J. S.; Dowell, Richard C.; Leigh, Jaime R.

doi: 10.1097/AUD.0b013e31803153f8
Research Articles

Background: The advent of universal neonatal hearing screening in some countries and the availability of screening programs for at-risk infants in other countries has facilitated earlier referral, diagnosis, and intervention for infants with hearing loss. Improvements in device technology, two decades of pediatric clinical experience, a growing recognition of the efficacy of cochlear implants for young children, and the recent change in the U.S. Food and Drug Administration's age criteria to include children as young as 12 mo has led to increasing numbers of young children receiving cochlear implants. Evidence to support provision for infants younger than 12 mo is extrapolated from physiological studies, studies of children using hearing aids, and studies of children older than 12 mo of age with implants. To date, however, there are few published research findings regarding communication development in children between 6 and 12 mo of age who receive implants. The current study hypothesized that earlier implantation would lead to increased rates of language acquisition as the children were still in the critical period for their development.

Method: A retrospective review was completed for 19 infants (mean age at implantation, 0.88 yr; range, 0.61–1.07, SD 0.15) and 87 toddlers (mean age at implantation, 1.60 yr; range, 1.13–2.00, SD 0.24) who received the multichannel implant in Melbourne, Australia. Preimplantation audiological assessments for these children included aided and unaided audiograms, auditory brain stem response, auditory steady state response (ASSR), and otoacoustic emission and indicated profound to total bilateral hearing loss in all cases. Communication assessment included completion of the Rossetti Infant-Toddler Language Scale and educational psychologists' cognitive and motor assessment. Computed tomography scan, magnetic resonance imaging, and surgical records for all cases were reviewed. Postimplantation language assessments were reported in terms of the rate of growth over time on the language comprehension and language expression subscales of the Rossetti Infant-Toddler Language Scale.

Results: Results demonstrated that cochlear implantation may be performed safely in very young children with excellent language outcomes. The mean rates of receptive (1.12) and expressive (1.01) language growth for children receiving implants before the age of 12 mo were significantly greater than the rates achieved by children receiving implants between 12 and 24 mo, and matched growth rates achieved by normally hearing peers. These preliminary results support the provision of cochlear implants for children younger than 12 mo of age within experienced pediatric implantation centers.

The University of Melbourne (S.J.D., R.J.S.B., R.C.D.), Parkville, Australia; The Cooperative Research Centre for Cochlear Implant and Hearing Aid Innovation (S.J.D., R.J.S.B., R.C.D., J.R.L.), East Melbourne, Victoria, Australia; Cochlear Implant Clinic (S.J.D., R.J.S.B., R.C.D., J.R.L.), Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia; Radcliffe Infirmary (P.D.), Oxford, UK.

Address for correspondence: Dr. Shani Dettman, Cochlear Implant Clinic, The Royal Victorian Eye and Ear Hospital, 32 Gisborne Street, East Melbourne, 8002, Victoria, Australia. E-mail: sdettman@bionicear.org.

Received December 15, 2005; accepted May 17, 2006.

Widespread universal newborn hearing screening programs and increased general awareness of cochlear implants have resulted in increasing numbers of children younger than 12 mo of age being diagnosed and referred to implantation centers. The “earlier is better” argument as it relates to cochlear implants is supported by evidence from physiological studies and from studies of children using hearing aids. A younger age at implantation is also associated with optimum communication outcomes for children with cochlear implants.

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Physiological Studies

Auditory perception, that is, learning to listen, in hearing children as well as children with hearing loss, is associated with the regular occurrence of speech events coupled with the features of attention, memory, and meaning. If listening is not developed during the critical language learning years, a child's potential to use speech input is likely to deteriorate. The key feature of the developing auditory system is plasticity, which is present at birth and decreases with age (Ruben & Rapin, 1980). Evidence suggests that the myelination occurs early in life and enables stable neural connections to form so that memory and learning can develop (Ryugo, Limb, & Redd, 2000). The earlier that a child receives the cochlear implant, the greater is the child's potential to benefit from these critical periods of neural development.

Studies regarding the human fetus' ability to detect sound, neonates' preferences for their native language, fundamental frequency and prosodic cues (of the primary caregiver), coupled with a curtailing of perceptual discrimination skills toward the end of the first 12 mo suggest a phonological critical period from the 6th mo of fetal life to 12 mo chronological age (Ruben, 1997). So, from a neurolinguistic perspective, it appears possible that if phonological distinctions are not made in the first year post-implantation, long-term language processing difficulties will result. Ruben (1997) suggested “insufficient early phonological input results in flawed semantic and syntactic capacities” (p. 204).

There is also evidence from animal models and investigations of brain plasticity that suggests that auditory stimulation can facilitate preservation of auditory structures and reverse the effects of auditory deprivation (Matsushima, Shepherd, Seldon, Xu, & Clark, 1991; Shepherd, Hartmann, Heid, Hardie, & Klinke, 1997).

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Children Younger than 6 Mo Using Hearing Aids

For children using hearing aids, many of the negative effects of hearing loss on communication development can be prevented, or at least substantially minimized, if intervention and training are initiated early in life (Hayes & Northern, 1997; Yoshinaga-Itano, Sedey, Coulter, & Mehl, 1998). Studies have shown that early diagnosis and appropriate intervention for infants with hearing aids is associated with improvements in receptive and expressive language skills (Apuzzo & Yoshinaga-Itano, 1995; Markides, 1986; Robinshaw, 1995; White & White, 1987; Yoshinaga-Itano et al., 1998). Apuzzo and Yoshinaga-Itano (1995) demonstrated that children who were identified and aided in the first 2 mo of life had significantly better language development than children identified between 3 and 12 mo of age, despite significant hearing loss.

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Children Using Cochlear Implants

For children using cochlear implants, a younger age at surgery is associated with optimum speech perception, speech intelligibility (Dowell, Blamey, & Clark, 1995; Nikolopoulos, O'Donoghue, & Archbold, 1999; Waltzman & Cohen, 1998) and language outcomes (Hammes, Novak, Rotz, Wills, Edmondson, & Thomas, 2002; Kirk, Miyamoto, Lento, Ying, O'Neill, & Fears, 2002; Svirsky, Teoh, & Neuburger, 2004).

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Risks versus Benefits

Cochlear implants for infants younger than 12 mo should only be considered if the potential benefits outweigh the potential risks of the procedure. Objections to elective surgery in very young infants are sometimes raised with regard to the safety of general anesthesia in this age group. Outpatient anesthetic studies reported mortality rates of zero in healthy children for ophthalmological surgery (Petruscak, Smith, & Breslin, 1973; Romano, 1981); however, other studies reported that the risk of cardiac arrest increased with decreasing age (Cohen, Cameron, & Duncan, 1990; Tiret, Nivoche, Hatton, Desmonts, & Vourc'h, 1988). A history of anesthesia, emergency procedures, and/or fasting of less than 8 hr were risk factors for anesthetic complications (Tiret, Nivoche, Hatton, Desmonts, & Vourc'h, 1988). Initial findings of the Pediatric Perioperative Cardiac Arrest Registry* suggested that, of all cardiac arrests, 55% occurred in infants younger than 12 mo, and 43% occurred in infants younger than 5 mo. When data were analyzed according to the American Society of Anesthesiologist's physical status classification system, it was found that emergency procedures, not age alone, were predictive of infant mortality (Morray et al., 2000). Pediatric anesthesiologist's expertise was suggested as a possible factor in the incidence of critical pediatric perioperative events (Keenan, Shapiro, & Dawson, 1991), but the Pediatric Perioperative Cardiac Arrest Registry data, being from larger university-based and children's hospitals, not smaller and community hospitals, did not add support to this finding.

Waltzman and Cohen (1998) reported on the safe implantation of children between the ages of 12 and 24 mo. No additional surgical risk was reported for the younger children. The authors, however, acknowledged the difficulties inherent in documenting speech perception improvement with this young group due to the nature of the assessment materials. It was not possible to make valid comparisons with older children due to the differences in linguistic knowledge. Nikolopoulos et al. (1999) stated the need for long-term follow-up as children who were older at implantation initially performed tests better due to advanced cognitive skills, longer exposure to language, and greater familiarity with test conditions. This advantage gradually diminished over time as the children who were younger at implantation gradually overtook and outperformed them. Lesinski-Schiedat, Illg, Heermann, Bertram, and Lenarz (2004) reported there was no higher incidence of surgical complications, and higher mean speech perception scores for 27 children who were implanted under 12 months compared to 89 children implanted between 12 and 24 months (both group being tested at 2½ yr of age). The problem with reporting results in this way is that the younger group had, on average, 18 to 24 mo of device experience, whereas the older group had, on average, less than 12 mo and in some cases only 6 mo of device experience. Cochlear implantation was reported to be safe and facilitated normalization of babbling in 10 infants who underwent implantation before 12 mo (Colletti, Carner, Miorelli, Guida, Colletti, & Fiorino, 2005). Full insertions without perioperative or immediate postoperative surgical complications, and the development of auditory perception (Infant-Toddler Meaningful Auditory Integration Scale, open-set words and sentences) was reported for 18 children who received implants before 12 mo of age (Waltzman & Roland, 2005). One child underwent successful reimplantation after wound breakdown (thought to be due to eyeglass frame irritation) after 12 mo of device use. Anecdotal reports from parents and teachers indicated good development of speech production and language skill, but formal tests of language were not yet reported for this group.

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Language Outcomes

For children who were old enough to complete formal test procedures, language data are customarily reported in terms of the difference between the child's chronological and equivalent language age, gap index (El-Hakim, Levasseur, Blake, Papsin, Panesar, Mount, Steven, & Harrison, 2001), rate of growth over time, and/or developmental trajectory (Svirsky, Teoh, & Neuburger, 2004). Studies suggest that for children receiving cochlear implants during the critical language period, deficits associated with profound hearing loss may be minimized (Bollard, Shute, Popp, & Parisier, 1999; El-Hakim, Levasseur, Blake, Papsin, Panesar, Mount, Steven, & Harrison, 2001; Novak, Firszt, Rotz, Hammes, Reeder, & Willis, 2000; Robbins, Bollard, & Green, 1999; Robbins, Svirsky, & Kirk, 1997; Svirsky, Teoh, & Neuburger, 2004; Truy, Lina-Granade, Jonas, Martinon, Maison, Girard, Porot, & Morgon, 1998). Language outcomes for children with cochlear implants, however, vary considerably, and there are complex interactions between preexisting child and family characteristics, child intelligence, hearing thresholds, device used, mode of communication, and age (Connor, Hieber, Arts, & Zwolan, 2000; Dowell, Dettman, Blamey, Barker, & Clark, 2002; Geers, Nicholas, & Sedey, 2003; Musselman, Lindsay, & Wilson, 1988).

Studies examining the impact of the cochlear implant on language development need to select appropriate early indicators of language progress, rather than wait for the child to perform formal test procedures. Nott, Cowan, Brown and Wigglesworth (2003) used the Rossetti Infant-Toddler Language Scale (RI-TLS) (Rossetti, 1990) in addition to the MacArthur Communicative Developmental Inventories and parental diary entries to chart early lexical development in young children with profound hearing loss using cochlear implants and/or hearing aids. Good correlations were found between the diary entries, RI-TLS, and the Communicative Developmental Inventories.

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Rationale

The aim of the present study was to examine the receptive and expressive language growth of children who received implants before 12 mo of age compared to children who received them between 12 and 24 mo of age and to determine the prevalence of surgical and/or anesthetic complications. As most cochlear implantation centers do not routinely proceed with children younger than 6 mo, it is not yet possible to replicate the studies by Apuzzo and Yoshinaga-Itano (1995) or Yoshinaga-Itano et al. (1998), but it is possible to examine children using cochlear implants from 6 mo onward. Accurate records regarding prevalence of mapping and/or device problems are required as preverbal children may be unable to report changes in their hearing. Given potentially greater surgical and anesthetic risks in those younger than 12 mo of age, improved dissemination of appropriate evidence is required for parents trying to decide whether to proceed with cochlear implantation.

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Method

There were 106 children who received the Cochlear Ltd. multichannel implant at the Melbourne Cochlear Implant Clinic before the age of 24 mo. Each had profound bilateral sensorineural hearing loss, used the ACE or SPEAK speech-processing strategy with SPrint, ESPrit 3G, or Freedom speech processors, and used a range of communication modes. There were 19 children in group 1 (mean age at implantation, 0.88 yr; range, 0.61–1.07; SD 0.15) and 87 toddlers in group 2 (mean age at implantation, 1.60 yr; range, 1.13–2.00; SD 0.24). Individual demographic and developmental features for the 19 children who underwent implantation at younger than 12 mo of age are given in Table 1. Statistical comparisons between groups 1 and 2 for hearing level and cognitive status are given in Table 2.

TABLE 1

TABLE 1

TABLE 2

TABLE 2

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Cognitive Assessment

All children completed a standardized psychological, cognitive, and motor evaluation by an educational psychologist, using a range of assessment materials suitable for the age and developmental level of each child. There was one group 1 child with severe global delay (after meningitis), and eight group 2 children who had mild, moderate, or severe cognitive delay.

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Language Assessment

The RI-TLS (Rossetti, 1990) uses a combination of author observations, developmental hierarchies, and behaviors recognized by leading authorities in the field of infant/toddler assessment to assess the language skills of children from birth to 36 mo of age. The RI-TLS differs from other rating scales as it is appropriate for use from birth through to 3 yr of age and examines mastery or emergence of important aspects of preverbal and verbal interaction such as interaction-attachment, pragmatics, gesture, and play, in addition to 76 language comprehension and 93 language expression milestones. These milestones may be observed, elicited, or reported by the clinician and/or the primary caregiver within an interview/play interaction session.

It was desirable to obtain at least one test administration of the RI-TLS pre-implantation and at yearly intervals post-implantation, but this was not always achieved. All six subscales including Interaction-Attachment, Pragmatics, Gesture, Play, Language Comprehension (LC), and Language Expression (LE) were administered. Results are reported for 11 group 1 children and 36 group 2 children who completed two or more RI-TLS over time. The slope of the linear regression lines through the available data points for the subscales LC and LE were derived.

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Surgical

Computed tomography, magnetic resonance imaging, anesthetic, and surgical records for all 106 children were reviewed. In all cases, a minimally invasive surgical approach was used similar to that described by O'Donoghue and Nikolopoulos (2003). Before reversal of anesthesia, a plain radiograph of the mastoid was taken to check the position of the electrode. The functional status of the implant was tested with impedance and neural response telemetry. A head bandage was applied.

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Results

Rate of Language Growth

For the 11 group 1 subjects, the individual rates of growth for LC and LE are given in Figures 1 and 2, respectively. There was a significant difference between the average rate of growth for LC for group 1 (1.12) and group 2 (0.71) (t = 3.50, p < 0.001) (Table 2). There was also a significant difference between the rate of growth for LE for group 1 (1.01) and group 2 (0.68) (t = 3.38, p < 0.002) (Table 2). When data from all children with cognitive delay were removed from the analysis, the difference between the rates of growth remained statistically significant (Table 2).

Fig. 1. Individual growth rates for Language Comprehension (LC) subscale of the Rossetti Infant-Toddler Language Scale (RI-TLS); group 1 (

Fig. 1. Individual growth rates for Language Comprehension (LC) subscale of the Rossetti Infant-Toddler Language Scale (RI-TLS); group 1 (

Fig. 2. Individual growth rates for Language Expression (LE) subscale of Rossetti Infant-Toddler Language Scale (RI-TLS); group 1 (

Fig. 2. Individual growth rates for Language Expression (LE) subscale of Rossetti Infant-Toddler Language Scale (RI-TLS); group 1 (

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Surgical and Programming Considerations

Most children were discharged from the hospital 1 d after surgery and reviewed in the clinic after 1 wk. Activation of the device usually took place 2 to 3 wk after surgery. A number of children had a preimplantation history of ear infections that required careful management. One group 1 child presented with mastoiditis 6 d after discharge that resolved after readmission for intravenous antibiotics. There were three group 2 children who underwent explantation: one for infection after trauma (fall from a child's seat) at 4 mo post-implantation, one due to an unknown cause of device failure at 9 mo post-implantation, and one due to device failure (after a blow to the head) at 3 yr post-implantation. All three children underwent successful reimplantation and attended regular otological and audiological reviews.

Appropriate threshold levels were obtained for all children using visual reinforcement audiometry (Moore, Thompson, & Thompson, 1975; Moore & Wilson, 1978) and/or play audiometry (Wilson & Thompson, 1984) depending on the age, developmental stage, and response state of the child. Maximum comfort levels were obtained using language that was appropriate for each child's comprehension and were checked by eliciting an auropalpebral reflex (eye blink in response to a loudness discomfort level) and subsequently reducing levels by 30% (Rance & Dowell, 1997).

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Discussion

This study demonstrated that children who received the cochlear implant who were younger than the age of 12 mo could demonstrate language comprehension and expressive development comparable to that of their hearing peers. The rate of growth was significantly better than the rate of comprehension and expressive growth demonstrated by a group of children who received the implant between 12 and 24 mo of age.

The relationship between cognitive status and communication outcomes in previous literature suggests that children with cochlear implants who also demonstrate cognitive delays tend to progress more slowly than other children in the areas of speech perception (Dowell, Dettman, Blamey, Barker, & Clark, 2002; Isaacson, Hasenstab, Wohl, & Williams, 1996; Pyman, Blamey, Lacy, Clark, & Dowell, 2000; Tomov, Dettman, Barker, Dowell, Williams, & Hughes, 2002; Waltzman, Scalchunes, & Cohen, 2000) and language (Dettman, Tomov, Dowell, Barker, Hughes, Williams, & Saldic, 2003). As cognitive delays could potentially reduce the average rate of growth for the group 2 children, the language data from children who demonstrated mild, moderate, or severe delay were removed from the analysis. This had the effect of improving the group 2 mean rate of LC from 0.71 to 0.78 and LE from 0.68 to 0.73, but these rates were still statistically significantly poorer than the rates demonstrated by group 1 children. The poorest group 1 rates of development of LC (case 18, 0.78) and LE (case 4, 0.73) were coincidentally the same as the average group 2 rates (LC = 0.78, LE = 0.73).

Reporting of the language results in terms of the slope of the child's receptive and expressive development over a consistent time interval proved useful in this study. Making comparisons with normalized data for hearing children then enables clinicians to determine whether the gap between the children's chronological and equivalent language age is decreasing or increasing over time.

The finding that children who receive a cochlear implant at a younger age demonstrate better postimplantation language outcomes is consistent with previous research (Brackett & Zara, 1998; Hammes et al., 2002; Miyamoto, Houston, Kirk, Perdew, & Svirsky, 2003; Robbins, 2000; Yoshinaga-Itano et al., 1998). It must be noted that the average age at hearing aid fitting was also significantly different for group 1 (0.41 yr) and group 2 (0.92). Future research may consider cohorts of children matched for cognitive status, who variously receive hearing aids early/undergo implantation early, receive hearing aids late/undergo implantation early, and receive hearing aids late/undergo implantation late to examine the relative influence of these variables. It was not within the scope of this article to report on speech perception outcomes for this group of children; speech perception and emerging babble production will be the focus of subsequent publications.

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Conclusions

These preliminary comprehension and expression results obtained from this group of children, coupled with the absence of anesthetic and/or surgical complications, provides support for the consideration of cochlear implants for children younger than 12 mo of age. The children who underwent implantation at younger than 12 mo of age achieved mean rates of receptive (1.12) and expressive (1.01) language growth that were comparable to their normally hearing peers and were significantly greater than the rates achieved by children who underwent implantation between 12 and 24 mo of age. If normal rates of language acquisition can be maintained in this group, earlier cochlear implantation represents a cost benefit to the community due to improved employment opportunities and reduced reliance on specialized psychosocial and educational support.

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Acknowledgments

The authors acknowledge the Speech Pathologists and Audiologists at the Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.

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References

Apuzzo, M. L., Yoshinaga-Itano, C. (1995). Early identification of infants with significant hearing loss and the Minnesota Child Development Inventory. Seminars in Hearing, 16, 124–139.
Bollard, P. M., Chute, P. M., Popp, A., Parisier, S. C. (1999). Specific language growth in young children using the Clarion cochlear implant. Annals of Otology, Rhinology & Laryngology, 177, 119S–123S.
Brackett, D., Zara, C. (1998). Communication outcomes related to early implantation. American Journal of Otology, 19, 453–460.
Cohen, M. M., Cameron, C. B., Duncan, P. G. (1990). Pediatric anesthesia morbidity and mortality in the perioperative period. Anesthesia and Analgesia, 70, 160–167.
Colletti, V., Carner, M., Miorelli, V., Guida, M., Colletti, L., Fiorino, F. G. (2005). Cochlear implantation at under 12 months: report on 10 patients. Laryngoscope, 115, 445–449.
Connor, C., Hieber, S., Arts, H. A., Zwolan, T. A. (2000). Speech, vocabulary, and the education of children using cochlear implants: Oral or Total Communication. Journal of Speech, Language, and Hearing Research, 43, 1185–1204.
Dettman, S. J., Tomov, A. M., Dowell, R. C., Barker, E. J., Williams, S. S., Hughes, K. C., Saldic, I. (2003). Early language outcomes for children with multiple disabilities. Proceedings of the 9th Symposium on Cochlear Implants in Children, Washington, DC, April.
Dowell, R. C., Blamey, P., Clark, G. M. (1995). Potential limitations of cochlear implantations in children. In G. M. Clark & R. S. C. Cowan (Eds.), International Cochlear Implant, Speech and Hearing Symposium 1994. Annals of Otology, Rhinology and Laryngology, 166, 324S–327S.
Dowell, R. C., Dettman, S. J., Blamey, P. J., Barker, E. J., Clark, G. M. (2002). Speech perception in children using cochlear implants: prediction of long-term outcomes. Cochlear Implants International, 1, 1–18.
El-Hakim, H., Levasseur, J., Papsin, B., Panesar, J., Mount, R., Stevens, R., Harrison, R. (2001). Assessment of vocabulary development in children after cochlear implantation. Archives of Otolaryngology, Head, Neck and Surgery, 127, 153–159.
Geers, A. E., Brenner, C. (2003). Background and educational characteristics of prelingually deaf children implanted by five years of age. Ear and Hearing, 24, 2S–12S.
    Geers, A. E., Nicholas, J. G., Sedey, A. L. (2003). Language Skills of children with early cochlear implantation. Ear and Hearing, 24, 46S–58S.
    Hammes, D. M., Novak, M. A., Rotz, L. A., Wills, M., Edmondson, D. M., Thomas, J. F. (2002). Early identification and cochlear implantation: Critical factors for spoken language development. Annals of Otology Rhinology and Laryngology, 111, 74–78.
    Hayes, D., Northern, J. L. (Eds.), (1997). Infants and Hearing. San Diego: Singular Publishing Group Inc.
    Isaacson, J. E., Hasenstab, M. S., Wohl, D. L., Williams, G. H. (1996). Learning disability in children with post-meningitic cochlear implants. Archives of Otolaryngology, Head & Neck Surgery, 122, 929–936.
    Keenan, R. L., Shapiro, J. H., Dawson, K. (1991). Frequency of anaesthetic cardiac arrests in infants: effect of paediatric anaesthesiologists. Journal of Clinical Anesthesia, 3, 433–437.
    Kirk, K. I., Miyamoto, R. T., Lento, C. L., Ying, E, O'Neill, T., Fears, B. (2002). Effects of age at implantation in young children. Annals of Otology Rhinology and Laryngology, 111, 69–73.
    Lesinski-Schiedat, A., Illg, A., Heermann, R., Bertram, B., & Lenarz, T. (2004). Paediatric cochlear implantation in the first and second year of life: a comparative study. Cochlear Implants International, 5, 146–154.
    Markides, A. (1986). Age at fitting of hearing aids and speech intelligibility. British Journal of Audiology, 20, 165–7.
    Matsushima, J. I., Shepherd, R. K., Seldon, H. L., Xu, S. A., Clark, G. M. (1991). Electrical stimulation of the auditory nerve in deaf kittens: effects on cochlear nucleus morphology. Hearing Research, 51, 133–142.
    Miyamoto, R. T., Houston, D. M., Kirk, K. I., Perdew, A. E., Svirsky, M. A. (2003). Language development in deaf infants following cochlear implantation. Acta Otolaryngologica, 123, 241–244.
    Moore, J. M., Thompson, G., Thompson, M. (1975). Auditory localization of infants as a function of reinforcement conditions. Journal of Speech & Hearing Disorders, 40, 29–34.
    Moore, J. M., Wilson, W. R. (1978). Visual reinforcement audiometry (VRA) with infants. In S. Gerber & G. Mencher (Eds.), Early diagnosis of hearing loss (pp. 177–213). New York: Grune & Stratton.
    Morray, J. P., Geiduschek, J. M., Ramamoorthy, C., Haberkern, C. M., Hackel, A., Caplan, R. A., Domino, K. B., Posner, K., Cheney, F. W. (2000). Anesthesia-related cardiac arrest in children: Initial findings of the Pediatric Perioperative Cardiac Arrest (POCA) Registry. Anesthesiology, 93, 6–14.
    Musselman, C. R., Lindsay, P. H., Wilson, A. K. (1988). An evaluation of recent trends in preschool programming for hearing-impaired children. Journal of Speech and Hearing Disorders, 53, 71–88.
    Nikolopoulos, T. P., O'Donoghue, G. M., Archbold, S. (1999). Age at implantation: Its importance in pediatric cochlear implantation. Laryngoscope, 109, 595–500.
    Nott, P., Cowan, R. S. C., Brown, P. M., Wigglesworth, G. (2003). Assessment of language skills in young children with profound hearing loss under two years of age. Journal of Deaf Studies and Deaf Education, 8, 401–421.
    Novak, M. A., Firszt, J. B., Rotz, L. A., Hammes, D., Reeder, R., Willis, M. (2000). Cochlear implants in infants and toddlers. Annals of Otology, Rhinology and Laryngology, 185, 46S–49S.
    O'Donoghue, G. M., Nikolopoulos, T. P. (2003). Minimal access surgery for pediatric cochlear implantation. Otology and Neurotology, 23, 891–894.
    Petruscak, J., Smith, R. B., Breslin, P. (1973). Mortality related to ophthalmological surgery. Archives of Ophthalmology, 89, 106–109.
    Pyman, P., Blamey, P., Lacy, P., Clark, G., Dowell, R. (2000). The development of speech perception in children using cochlear implants: effects of etiological factors and delayed milestones. The American Journal of Otology, 21, 57–61.
    Rance, G., Dowell, R. C. (1997). Speech Processor Programming. In G. M. Clark, R. S. C. Cowan, & R. C. Dowell (Eds.), Cochlear Implantation for Infants & Children: Advances (pp. 147–170). San Diego: Singular Publishing Group Inc.
    Robinshaw, H. M. (1995). Early intervention for hearing impairment: Differences in the timing of communicative and linguistic development. British Journal of Audiology, 28, 315–334.
    Robbins, A. M. (2000). Language Development. In S. B. Waltzman, & N. L. Cohen, (Eds.). Cochlear Implants (pp. 269–283). New York: Thieme.
    Robbins, A. M., Bollard, P., Green, J. (1999). Language development in children implanted with the CLARION cochlear implant. Annals of Otology, Rhinology and Laryngology, 177, 113S–118S.
    Robbins, A. M., Svirsky, M., & Kirk, K. I. (1997). Children with implants can speak, but can they communicate? Otolaryngology-Head & Neck Surgery, 117, 155–160.
    Romano, P. (1981). General anesthesia morbidity and mortality in eye surgery at children's hospitals. Journal of Pediatric Ophthalmology and Strabismus, 18, 17–21.
    Rossetti, L. M. (1990). The Rossetti Infant-Toddler Language Scale. East Moline, IL: LinguiSystems.
    Ruben, R. J. (1997). A time frame of critical/sensitive periods of language development. Acta Otolaryngologica, 117, 202–205.
    Ruben, R. J., Rapin, I. (1980). Plasticity of the developing auditory system. Annals of Otolaryngology, 89, 303–311.
    Ryugo, D. K., Limb, C. J., Redd, E. E. (2000). Brain Plasticity: The impact of the environment on the brain as it relates to hearing and deafness. In J. K. Niparko, N. K. Mellon, A. M. Robbins, D. L. Tucci, & B. S. Wilson (Eds.), Cochlear Implants: Principles and Practices. (pp. 33–56). Philadelphia: Lippincott Williams & Wilkins.
    Shepherd, R. K., Hartmann, R., Heid, S., Hardie, N., Klinke, R. (1997). The central auditory system and auditory deprivation experience with cochlear implants in the congenitally deaf. Acta Otolaryngology, 532, 28S–33S.
    Svirsky, M. A., Teoh, S-W., Neuberger, H. (2004). Development of language and speech perception in congenitally, profoundly deaf children as a function of age at cochlear implantation. Audiology and Neuro-otology, 9, 224–233.
    Tiret, L., Nivoche, Y., Hatton, Y., Desmonts, J. M., Vourc'h, G. (1988). Complications related to anaesthesia in infants and children: a prospective survey of 40240 anaesthetics. British Journal of Anaesthesia, 61, 263–269.
    Tomov, A. M., Dettman, S. J., Barker, E. J., Dowell, R. C., Williams, S. S., Hughes, K. C. (2002). Cochlear implant outcomes in children with multiple disabilities. Paper presented at the 7th International Cochlear Implant Conference, Manchester, UK, September.
    Truy, E., Lina-Granade, G., Jonas, A., Martinon, G., Maison, S., Girard, J., Porot, M., Morgon, A. (1998). Comprehension of language in congenitally deaf children with and without cochlear implants. International Journal of Pediatric Otorhinolaryngology, 45, 83–89.
    Waltzman, S., Cohen, N. (1998). Evaluating implant benefit in children younger than 2 years of age. American Journal of Otolaryngology, 19, 158–162.
    Waltzman, S. B., Scalchunes, V., Cohen, N. L. (2000). Performance of multiply handicapped children using cochlear implants. The American Journal of Otology, 21, 329–335.
    Waltzman, S. B., Roland, J. T. (2005). Cochlear implantation in children younger than 12 months. Pediatrics, 116, 487–493.
    White, S. J., White, R. E. C. (1987). The effects of hearing status of the family and age of intervention on receptive and expressive oral language skills in hearing impaired infants. Monographs of the American Speech, Language and Hearing Association, 26, 9–24.
    Wilson, W. R., Thompson, G. (1984). Behavioural audiometry. In J. Jerger (Ed.), Paediatric Audiology (pp. 1–44). San Diego: College-Hill Press.
    Yoshinaga-Itano, C., Sedey, A. L., Coulter, D. K., Mehl, A. L. (1998). Language of early- and later-identified children with hearing loss. Pediatrics, 102, 1161–1171.

    *The Pediatric Perioperative Cardiac Arrest Registry is an U.S.-based registry that was established to collect data regarding pediatric cardiac arrests and deaths in the perioperative and immediate postoperative period and analyze causal relationships.
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