Cochlear Implants for Deaf Children With Early Developmental Impairment

BACKGROUND AND OBJECTIVES: Infants with profound hearing loss are typically considered for cochlear implantation. Many insurance providers deny implantation to children with developmental impairments because they have limited potential to acquire verbal communication. We took advantage of differing insurance coverage restrictions to compare outcomes after cochlear implantation or continued hearing aid use. METHODS: Young children with deafness were identified prospectively from 2 different states, Texas and California, and followed longitudinally for an average of 2 years. Children in cohort 1 ( n 5 138) had normal cognition and adaptive behavior and underwent cochlear implantation. Children in cohorts 2 ( n 5 37) and 3 ( n 5 29) had low cognition and low adaptive behavior. Those in cohort 2 underwent cochlear implantation, whereas those in cohort 3 were treated with hearing aids. RESULTS: Cohorts did not substantially differ in demographic characteristics. Using cohort 2 as the reference, children in cohort 1 showed more rapid gains in cognitive, adaptive function, language, and auditory skills (estimated coefficients, 0.166 to 0.403; P # .001), whereas children in cohort 3 showed slower gains ( (cid:1) 0.119 to (cid:1) 0.243; P # .04). Children in cohort 3 also had greater increases in stress within the parent-child system (1.328; P 5 .02), whereas cohorts 1 and 2 were not different. CONCLUSIONS: Cochlear implantation benefits children with deafness and developmental delays. This finding has health policy implications not only for private insurers but also for large, statewide, publicly administered programs. Cognitive and adaptive skills should not be used as a “ litmus test ” for pediatric cochlear implantation.

WHAT'S KNOWN ON THIS SUBJECT: Cochlear implantation has become the standard of care for children with deafness because it permits better speech and language acquisition.However, coexistent severe developmental delays have been used by insurance providers as a rationale to deny coverage for this treatment.

WHAT THIS STUDY ADDS:
We demonstrate in this prospective cohort study in children with deafness and severe developmental impairment substantial benefits of cochlear implantation over hearing aids.Cognitive and adaptive skills should not be used as a "litmus test" for cochlear implantation.
In the United States, 0.1% to 0.3% of newborn infants have sensorineural hearing loss. 1 A strong consensus is that early detection and appropriate treatment is essential to allow children to maximize their developmental skills, particularly in the domains of language and speech.The first step is always amplification through hearing aids, which should be provided before the children reach age 6 months. 2If children with profound hearing loss fail to develop early skills in language and speech despite hearing aids, they become eligible for cochlear implantation.[5][6] Children with profound hearing loss may have associated deficits or impairment in other developmental domains, including nonverbal cognitive skills and adaptive function.Heretofore, we refer to the combination of low cognition and adaptive function as early developmental impairment (EDI).Common causes of both hearing loss and EDI include complications of preterm birth, genetic or chromosomal abnormalities, and hypoxic-ischemic encephalopathy. 7f these children continue to show cognitive impairment and disorders in adaptive behavior into school age, they may later meet criteria for intellectual disability.The optimal therapeutic regimen for children with profound hearing loss and EDI is not straightforward because even children with normal hearing and EDI may not develop ageappropriate spoken communication skills. 8Many studies of pediatric cochlear implantation in children with additional disabilities have revealed either no effect or limited improvements in speech perception, speech production, and spoken language. 9-12][15][16][17] Thus, even though a child with severe EDI may have better hearing through a cochlear implant than through hearing aids, they are likely to have minimal improvement in speech and language. 18r this reason, some medical insurance programs may not cover cochlear implantation for a child with EDI.For example, the publicly administered California Children's Services program has excluded these children from payment for cochlear implantation, and only recently administrators have agreed to cover implantation for select patients. 19,20n contrast, the analogous Children's Health Insurance Program in Texas typically covers cochlear implantation for most children with EDI.In both California and Texas, some private insurance plans also do not cover cochlear implantation for children with severe developmental delays.This study was motivated by our impression from providing cochlear implantation to selected patients with EDI that these children also benefited from early cochlear implantation.21,22 Although authors of many other studies have compared outcomes after cochlear implantation versus hearing aids, the data regarding children with additional needs are sparse.18 Here, we took advantage of insurance coverage differences to compare the outcomes of deaf children with EDI who underwent cochlear implantation versus those who continued to use hearing aids.We hypothesized that deaf children with EDI would benefit from cochlear implantation in highly meaningful ways not exclusive to auditory and language development.

Study Design
A prospective longitudinal cohort study was performed that included all children identified with severe to profound sensorineural hearing loss managed by 2 large pediatric cochlear implant centers: All children started with hearing aids.When performed, the cochlear implantation surgery was $1 month after the baseline assessment.The only exceptions were children younger than the minimum age approved by the US Food and Drug Administration for cochlear implantation (12 months).For these patients, implantation was performed within the month after the children's first birthday.Followup evaluations were scheduled annually using the same assessment protocol.

Definition of EDI
Developmental impairment was defined on the basis of scores on nonverbal cognitive skills and adaptive functioning.To estimate cognition, we used the visual reception domain from the MSEL.To assess adaptive behavior, we used the daily living skills domain from the VABS.The other domains were excluded because of the possibility that results may not reflect actual capability due to either reduced receptive and expressive language or motor delays.Previously, we validated these 2 measures in a patient population with hearing loss and EDI, and we defined meaningful thresholds for EDI guided by standard definitions of intellectual disability. 21,23,24Children who scored 2 SDs below the mean for their age in the visual reception domain of the MSEL met the criterion for low nonverbal cognitive skills.Children who scored 1 SD below their age in the daily living skills domain of the VABS met the criterion for low adaptive behavior.Normal nonverbal cognitive skills and normal adaptive behavior were defined as being above these thresholds.Thus, children who met our definition of EDI had severe developmental delays.

Statistical Analyses
For comparing the patient characteristics, which were categorical variables (Table 1), we used the Fisher's exact test for proportions.For comparing the developmental outcomes, which were continuous variables (Table 2), we used analysis of variance followed by Tukey's post hoc subgroup comparisons.In both cases, adjusted P values were used to account for multiple comparisons.To perform linear fits for each developmental outcome for each cohort (Fig 2 ), we used least squares regression.To compare developmental trajectories among the 3 cohorts (Table 3), we used hierarchical linear modeling.Testing age and cohort number were used as fixed-effects predictors, and the subject identifier code was used as a random effect predictor.This statistical approach was chosen for these longitudinal data because the resulting models provide estimates for growth rate, which has less error than each individual data point for each child.The method is also advantageous because it is permissive regarding missing data and can account for random variations in follow-up testing age between subjects.For all analyses, we adjusted for simultaneous inference by term, and the threshold for statistical significance was set at P < .05.Confidence intervals (CIs) were calculated at 95%.Analyses were conducted in R, and figures were  5) produced using the package ggplot2. 25,26

Stratification of Cohorts
From the 297 children enrolled in this longitudinal study, 3 subgroups were formed (Fig 1 We found no differences among the cohorts on the basis of study site,

FIGURE 1
Enrollment, cohort assignment, and developmental outcome assessment.
sex, household income, race, or mother's education level (Table 1).As expected, there was a higher rate of preterm births in both cohort 2 and cohort 3 compared with cohort 1.There were also differences among the cohorts in the rates of living in an urban or rural environment, ethnicity, and preferred language, with higher rates of urban Hispanic, Spanishspeaking families in cohort 1.
Because we had no hypotheses about the interaction of these demographics with our outcome data, we assumed that the significant P values represented random statistical variability and did not include any demographic data in further analyses.

Developmental Outcomes
Baseline data were collected at the time of enrollment, with repeated evaluations performed approximately annually over the next 1 to 5 years.The final evaluation was defined as the last data point we collected before the grant ended.During the study, 39 of the children in cohort 1 and 5 of the children in cohort 2 were lost to follow-up, typically because their family moved out of town.Interestingly, none of the children in cohort 3 were lost to follow-up.The rates of attrition were acceptable for a study of this duration.Children in cohorts 1 and 2 had more follow-up evaluations than children in cohort 3 (Table 2).This difference is not surprising because insurers who were willing to cover cochlear implantation were also willing to cover repeated neurocognitive examinations.
At baseline, cohort 1 was the youngest and cohort 3 was the oldest.There were no differences in cognition, adaptive behavior, language, auditory skills, or stress within the parent-child system between cohorts 2 and 3.Because the children were all deaf, cohort 1 had language and auditory skills like cohorts 2 and 3.However, cohort 1 had less stress within the parentchild system relative to the 2 other cohorts.By the time of final testing, average developmental scores were highest for cohort 1 and lowest for cohort 3.

Developmental Trajectories
Next, we compared the developmental trajectory for each cohort by calculating a linear fit for all evaluations from birth, where all developmental ages and raw scores would be 0, with the final evaluation (Fig 2).However, to compare the growth trajectories, we did not simply compare these linear fits.
Instead, we performed hierarchical linear modeling (Table 3).This analysis permitted us to control for age of testing, differences in the number of follow-up evaluations, and random differences between individuals.The estimated coefficient values reflect the differences in the slope of either cohort 1 or 3 compared with cohort 2. Positive values mean that the slope is steeper than for cohort 2; negative values mean that the slope is shallower.
To To assess for changes in stress within the parent-child system, we plotted the PSI score versus chronological age.There were no differences between cohorts 1 and 2, but cohort 3 demonstrated more stress in the parent-child system over time.
developmental impairment who did not receive a cochlear implant and continued to use appropriately fitted hearing aids.Each dot is the test result for 1 child, the blue lines are the linear fits, and the gray-shaded region is the 95% CI.The slopes and R 2 of the fit lines are shown in the upper left quadrant of each analysis.The P values come from the interaction term between age and either cohort 1 versus 2 (age:cohort 1-2 in Table 3) or cohort 2 versus 3 (age:cohort 2-3 in Table 3) in the hierarchical linear modeling analysis.Dev, developmental.
To verify that site did not affect these findings, we repeated the hierarchical linear modeling analysis, including site as a random effect.This produced only slight changes in the values given in Table 3, and the statistical significances for every finding did not change.

DISCUSSION
In We attempted to overcome our inability to perform a controlled clinical trial by capitalizing on differences in insurance coverage to create randomization.However, we could not determine with certainty the underlying reasons for the decisions made by families of children with deafness and EDI in opting for cochlear implants or hearing aids.For most of the families in cohort 3, the decision regarding cochlear implantation was taken out of their hands by the reimbursement agency.Nevertheless, it was impossible to quantify how differing eligibility policies affected the implantation rate because neither pediatric cochlear implant team determined the care plan for any patient solely on the basis of insurance coverage.Instead, according to best practice, the teams described the risks, benefits, and typical outcomes for hearing aids and for cochlear implantation.The parents then decided how they wished to proceed.Interestingly, none of the families whose child was denied by insurance was adamant about receiving a cochlear implant.Over time and repeated visits, most parents ultimately determined for themselves that cochlear implantation would not be best for their child.In contrast, parents who did not have this eligibility issue tended to make the decision to proceed with implantation.
Another caveat is that these children were only followed for an average of 2 years after their initial evaluation.We know that in children with normal intelligence, cochlear implantation produces better longterm outcomes than hearing aids. 31lthough we found that children with EDI treated with hearing aids have a slower developmental trajectory than those treated with cochlear implantation, it is possible that both cohorts will ultimately end up with similar developmental outcomes.
To conclude, our data are supportive of the value of cochlear implantation in children with multiple disabilities/ developmental delays and provide an argument against insurance plans requiring that certain developmental milestones be met prior to authorization.Developmental impairments will adversely affect a child's outcome after cochlear implantation because the combination of hearing loss and EDI synergistically affect other developmental outcomes, with the loss of auditory input creating a cascade of higher-order neurocognitive deficits. 32This outcome should be discussed carefully with the parents to ensure that their expectations are appropriate.However, EDI should not be the deciding factor alone.Every child is an individual and has unique health and developmental limitations, together with unique family, home, and school environments.All these factors should be considered during the process of cochlear implantation candidacy.

ACKNOWLEDGMENTS
We

FIGURE 2
FIGURE 2 Developmental trajectories.Cohort 1 included children with normal cognitive skills and normal adaptive behavior who underwent cochlear implantation.Cohort 2 included children with early developmental impairment who underwent cochlear implantation.Cohort 3 included children with early

TABLE 1
Patient Characteristics
thank E. O'Brian Smith, Lane Strathearn, Ann Stark, Jody Haymond, Sue Caudle, Dian Baker, Ross Tonini, Homer Abaya, Jody Winzelberg, Barbara Bentley, Ryan Lucash, Laurie Eisenberg, and Karen Johnson for their contributions.Deidentified individual subject data (including data dictionaries) will be made available, in addition to study protocols, the statistical analysis plan, and the informed consent form.The data will be made available upon publication to researchers who provide a methodologically sound proposal for use in achieving the goals of the approved proposal.Proposals should be submitted to oghalai@usc.edu.