Quality of Life and Cost-Effectiveness of Cochlear Implants: A Narrative Review.

OBJECTIVES: To review evidence regarding the health-related quality of life (HRQoL) and cost-effectiveness of unilateral and bilateral cochlear implantation (CI) among children and adults with severe-to-profound hearing loss. STUDY DESIGN: Narrative review. METHODS: Publications related to quality of life (QoL) and costs of care in CI were acquired through searches in English-language databases. Studies were included if they had identified the HRQoL attainment, cost of care, cost-utility, or cost-effectiveness associated with CI. RESULTS: 57 studies were critically reviewed. The QoL outcome metrics used in these articles were divided into 2 categories - generic and condition specific. In studies investigating children, many reported no significant difference in QoL attainment between CI recipients and normal-hearing peers. In adults, significant improvements in QoL after implantation and higher QoL than in their nonimplanted (hearing-aided) peers were frequently reported. Studies involving an older adult cohort reported significant improvement in QoL after implantation, which was often independent of audiological performance. Overall, the calculated cost-utility ratios consistently met the threshold of cost acceptance, indicating acceptable values for expenditures on CI. CONCLUSIONS: Considerable work has been done on the QoL attainment and health economic implications of CI. Unilateral CI across all age groups leads to reported sustained benefits in the recipients' overall and disease-specific QoL. With increased cost associated with bilateral CI, further study is needed to characterize its costs and benefits with respect to the recipients' health, well-being, and contributions to society.

Ultra-High-Field Magnetic Resonance Imaging of the Human Inner Ear at 11.7 Tesla.

OBJECTIVE: To evaluate the ability of ultra-high-field magnetic resonance imaging (UHF-MRI) at 11.7 T to visualize membranous structures of the human inner ear. SPECIMENS: Three temporal bones were extracted from cadaveric human heads for use with small-bore UHF-MRI. INTERVENTION: Ex vivo cadaveric temporal bone specimens were imaged using an 11.7 T magnetic resonance imaging (MRI) scanner via T1- and T2-weighted-imaging with and without contrast. MAIN OUTCOME MEASURE: Qualitative visualization of membranous components of the inner ear compared with reports of UHF-MRI at lower field strengths. RESULTS: The membranous anatomy of the inner ear was superbly visualized at 11.7 T. In the cochlea, Reissner's membrane, the scala media, and the basilar membrane were clearly shown on the scan. In the vestibular labyrinth, the wedge-shaped crista ampullaris and the maculae of both the saccule and utricle were visible. Details of the endolymphatic sac and duct were also demonstrated. CONCLUSION: To our knowledge, this report presents the first images of the ex vivo human inner ear using 11.7 T UHF-MRI, offering near-histologic resolution. Increased field strength may be particularly useful when imaging the delicate membranous anatomy of the inner ear. Further research on the use of UHF-MRI in clinical and research settings could illuminate structural changes associated with inner ear disorders.

Symbolic Play and Novel Noun Learning in Deaf and Hearing Children: Longitudinal Effects of Access to Sound on Early Precursors of Language.

In the largest, longitudinal study of young, deaf children before and three years after cochlear implantation, we compared symbolic play and novel noun learning to age-matched hearing peers. Participants were 180 children from six cochlear implant centers and 96 hearing children. Symbolic play was measured during five minutes of videotaped, structured solitary play. Play was coded as "symbolic" if the child used substitution (e.g., a wooden block as a bed). Novel noun learning was measured in 10 trials using a novel object and a distractor. Cochlear implant vs. normal hearing children were delayed in their use of symbolic play, however, those implanted before vs. after age two performed significantly better. Children with cochlear implants were also delayed in novel noun learning (median delay 1.54 years), with minimal evidence of catch-up growth. Quality of parent-child interactions was positively related to performance on the novel noun learning, but not symbolic play task. Early implantation was beneficial for both achievement of symbolic play and novel noun learning. Further, maternal sensitivity and linguistic stimulation by parents positively affected noun learning skills, although children with cochlear implants still lagged in comparison to hearing peers.

Sentence Recognition in Quiet and Noise by Pediatric Cochlear Implant Users: Relationships to Spoken Language.

OBJECTIVE: We investigated associations between sentence recognition and spoken language for children with cochlear implants (CI) enrolled in the Childhood Development after Cochlear Implantation (CDaCI) study. STUDY DESIGN: In a prospective longitudinal study, sentence recognition percent-correct scores and language standard scores were correlated at 48-, 60-, and 72-months post-CI activation. SETTING: Six tertiary CI centers in the United States. PATIENTS: Children with CIs participating in the CDaCI study. INTERVENTION (S): Cochlear implantation. MAIN OUTCOME MEASURE (S): Sentence recognition was assessed using the Hearing In Noise Test for Children (HINT-C) in quiet and at +10, +5, and 0 dB signal-to-noise ratio (S/N). Spoken language was assessed using the Clinical Assessment of Spoken Language (CASL) core composite and the antonyms, paragraph comprehension (syntax comprehension), syntax construction (expression), and pragmatic judgment tests. RESULTS: Positive linear relationships were found between CASL scores and HINT-C sentence scores when the sentences were delivered in quiet and at +10 and +5 dB S/N, but not at 0 dB S/N. At 48 months post-CI, sentence scores at +10 and +5 dB S/N were most strongly associated with CASL antonyms. At 60 and 72 months, sentence recognition in noise was most strongly associated with paragraph comprehension and syntax construction. CONCLUSIONS: Children with CIs learn spoken language in a variety of acoustic environments. Despite the observed inconsistent performance in different listening situations and noise-challenged environments, many children with CIs are able to build lexicons and learn the rules of grammar that enable recognition of sentences.

Should All Deaf Children Learn Sign Language?

Every year, 10,000 infants are born in the United States with sensorineural deafness. Deaf children of hearing (and nonsigning) parents are unique among all children in the world in that they cannot easily or naturally learn the language that their parents speak. These parents face tough choices. Should they seek a cochlear implant for their child? If so, should they also learn to sign? As pediatricians, we need to help parents understand the risks and benefits of different approaches to parent-child communication when the child is deaf [corrected].

A Prospective Longitudinal Study of U.S. Children Unable to Achieve Open-Set Speech Recognition 5 Years After Cochlear Implantation.

OBJECTIVE: To identify characteristics associated with the inability to progress to open-set speech recognition in children 5 years after cochlear implantation. STUDY DESIGN: Prospective, longitudinal, and multidimensional assessment of auditory development for 5 years. SETTING: Six tertiary cochlear implant (CI) referral centers in the United States. PATIENTS: Children with severe-to-profound hearing loss who underwent implantation before age 5 years enrolled in the Childhood Development after Cochlear Implantation study, categorized by level of speech recognition ability. INTERVENTION(S): Cochlear implantation before 5 years of age and annual assessment of emergent speech recognition skills. MAIN OUTCOME MEASURE(S): Progression to open-set speech recognition by 5 years after implantation. RESULTS: Less functional hearing before implantation, older age at onset of amplification, lower maternal sensitivity to communication needs, minority status, and complicated perinatal history were associated with the inability to obtain open-set speech recognition by 5 years. CONCLUSION: Characteristics of a subpopulation of children with CIs associated with an inability to achieve open-set speech recognition after 5 years of CI experience were investigated. These data distinguish pediatric CI recipients at risk for poor auditory development and highlight areas for future interventions to enhance support of early implantation.

Aphasia: Current Concepts in Theory and Practice.

Recent advances in neuroimaging contribute to a new insights regarding brain-behavior relationships and expand understanding of the functional neuroanatomy of language. Modern concepts of the functional neuroanatomy of language invoke rich and complex models of language comprehension and expression, such as dual stream networks. Increasingly, aphasia is seen as a disruption of cognitive processes underlying language. Rehabilitation of aphasia incorporates evidence based and person-centered approaches. Novel techniques, such as methods of delivering cortical brain stimulation to modulate cortical excitability, such as repetitive transcranial magnetic stimulation and transcranial direct current stimulation, are just beginning to be explored. In this review, we discuss the historical context of the foundations of neuroscientific approaches to language. We sample the emergent theoretical models of the neural substrates of language and cognitive processes underlying aphasia that contribute to more refined and nuanced concepts of language. Current concepts of aphasia rehabilitation are reviewed, including the promising role of cortical stimulation as an adjunct to behavioral therapy and changes in therapeutic approaches based on principles of neuroplasticity and evidence-based/person-centered practice to optimize functional outcomes.

Development of joint engagement in young deaf and hearing children: effects of chronological age and language skills.

PURPOSE: To evaluate joint engagement (JE) in age-matched children with and without hearing and its relationship to oral language skills. METHOD: Participants were 180 children with severe-to-profound hearing loss prior to cochlear implant surgery, and 96 age-matched children with normal hearing; all parents were hearing. JE was evaluated in a 10-minute videotaped free play task with parents. Engagement states ranged from the lowest (unengaged) to the highest level (symbol-infused coordinated). Standardized language measures were administered. RESULTS: Multivariate analyses were conducted between the groups, stratified by chronological and language age. Children who were deaf (Deaf) spent less time in total symbol-infused JE than children with normal hearing (NH) across all ages. The majority of the Deaf group (83%) fell in the lowest language age group, in comparison to 35% of the NH group, and spent significantly less time in symbol-infused JE than hearing children. These delays were also observed in the Deaf group, who fell into the 18-36 month language age. No children in the Deaf group had achieved a language age of > 36 months. CONCLUSIONS: Young children with and without hearing had different developmental trajectories of JE, which were related to oral language skills.

Correlation of neurocognitive processing subtypes with language performance in young children with cochlear implants.

OBJECTIVES: Test data were used to explore the neurocognitive processing of a group of children with cochlear implants (CIs) whose language development is below expectations. METHODS: This cross-sectional study examines the relationship between neurocognitive processing, as assessed by the Kaufman Assessment Battery for Children-Second Edition, and verbal language standard scores, assessed using either the Comprehensive Assessment of Spoken Language or the Clinical Evaluation of Language Fundamentals in 22 school-age children with CIs. Processing scores of CI recipients with language scores below expectations were compared to those of children meeting or exceeding language expectations. Multiple linear regression estimated the associations of simultaneous and sequential processing with language scores. RESULTS: Though simultaneous processing scores between the two groups were similar, the mean sequential processing score (91.2) in the below expectations group (n = 13) was significantly lower (P = 0.002) than that of children (n = 9) meeting expectations (110.8). After adjusting for age at implantation, a 10-point higher sequential processing score was associated with a 7.4 higher language score (P = 0.027). DISCUSSION: Simultaneous processing capacity was at least within the average range of cognitive performance, and was not associated with language performance in children with CIs. Conversely, reduced sequential processing capacity was significantly associated with lower language scores. CONCLUSION: Neurocognitive skills, specifically cognitive sequencing, serial ordering, and auditory-verbal memory may be targets for therapeutic intervention. Intensive cognitive and educational habilitation and in milieu intervention may improve language learning in children with CIs.

Robot-assisted three-dimensional registration for cochlear implant surgery using a common-path swept-source optical coherence tomography probe.

Cochlear implantation offers the potential to restore sensitive hearing in patients with severe to profound deafness. However, surgical placement of the electrode array within the cochlea can produce trauma to sensorineural components, particularly if the initial turn of the cochlea is not successfully navigated as the array is advanced. In this work, we present a robot-mounted common-path swept-source optical coherence tomography endoscopic platform for three-dimensional (3-D) optical coherence tomography (OCT) registration and preoperative surgical planning for cochlear implant surgery. The platform is composed of a common-path 600-µm diameter fiber optic rotary probe attached to a five degrees of freedom robot capable of 1 µm precision movement. The system is tested on a dry fixed ex vivo human temporal bone, and we demonstrate the feasibility of a 3-D OCT registration of the cochlea to accurately describe the spatial and angular profiles of the canal formed by the scala tympani into the first cochlear turn.

Long-term use of cochlear implants in older adults: results from a large consecutive case series.

OBJECTIVE: To investigate rates of long-term use of cochlear implants in a large, consecutive case series of older adults (≥60 yr). STUDY DESIGN: Consecutive case series. SETTING: Tertiary referral center. PATIENTS: Approximately 447 individuals 60 years or older who received their first CI from 1999 to 2011. We successfully contacted 397 individuals (89%) to ascertain data on the individual's daily CI use averaged over the past 4 weeks. INTERVENTION: Cochlear implantation. MAIN OUTCOME MEASURE: Regular CI use was defined as 8 hours or greater of use per day. We investigated the time from implantation to the date when an individual reported discontinuing regular CI use. RESULTS: The overall rate of regular CI use at 13.5 years of follow-up was 82.6% (95% CI, 72.5%-89.3%). Individuals who received a CI at 60 to 74 years had significantly higher rates of regular CI use at 13.5 years of follow-up (91.1% [95% CI, 83.2%-95.4%], n = 251) than individuals who received a CI at 75 years or older (55.7% [95% CI, 24.9%-78.1%], n = 146). The rate of discontinuing regular CI use (<8 hr/d) increased on average by 7.8% (95% CI, 3.0%-12.8%) per year of age at implantation. CONCLUSION: Rates of long-term CI use in older adults at more than 10 years of follow-up exceed 80%. The rate of discontinuing regular CI use was strongly associated with older age at implantation. These results suggest that early implantation of older adults, once critically low levels of speech recognition are present, is associated with greater usage of the device.

Assessment of health-related quality of life 6 years after childhood cochlear implantation.

PURPOSE: To examine the impact of cochlear implant (CI) intervention on health-related quality of life (HRQOL) assessed by both self- and parent-reported measures. METHODS: In this national study of children implanted between ages 6 months and 5 years, HRQOL of 129 children 6-year post-CI was compared to 62 internal study (NH1) and 185 external (NH2) samples of hearing children frequency-matched to the CI group on sociodemographic variables. HRQOL ratings of children and their parents in each group, measured using the Child Health and Illness Profile-Child Edition, were compared, and their associations with the Family Stress Scale were investigated. RESULTS: CI children reported overall and domain-specific HRQOL that was comparable to both NH1 and NH2 peers. CI parents reported worse child scores than NH1 parents in Achievement, Resilience, and Global score (p's < 0.01) but similar or better scores than socioeconomically comparable NH2 parents. Higher family stress was negatively associated with all parent-reported HRQOL outcomes (p's < 0.01). Parent-child correlations in HRQOL global scores trended higher in CI recipients (r = 0.50) than NH1 (r = 0.42) and NH2 (r = 0.35) controls. CONCLUSIONS: CI recipients report HRQOL comparable to NH peers. These results, from both child and parent perspective, lend support to the effectiveness of CI intervention in mitigating the impact of early childhood deafness. Family stress was associated with worse HRQOL, underscoring a potential therapeutic target. Parent-child agreement in HRQOL scores was higher for CI families than NH families, which may reflect higher caregiver insight and involvement related to the CI intervention.

Mitigation of informational masking in individuals with single-sided deafness by integrated bone conduction hearing aids.

OBJECTIVES: To confirm an increased susceptibility to informational masking among individuals with single-sided deafness (SSD). To demonstrate a reduction in informational masking when SSD is treated with an integrated bone conduction hearing aid (IBC). To identify the acoustic cues that contribute to IBC-aided masking release. To determine the effects of device experience on the IBC advantage. DESIGN: Informational masking was evaluated with the coordinate-response measure. Participants performed the task by reporting color and number coordinates that changed randomly within target sentences. The target sentences were presented in free field accompanied by zero to three distracting sentences. Target and distracting sentences were spoken by different talkers and originated from different source locations, creating two sources of information for auditory streaming. Susceptibility to informational masking was inferred from the error rates of unaided SSD patients relative to normal controls. These baseline measures were derived by testing inexperienced IBC users without the device on the day of their initial fitting. The benefits of IBC-aided listening were assessed by measuring the aided performance of users who had at least 3 months' device experience. The acoustic basis of the listening advantage was isolated by correlating response errors with the voice pitch and location of distracting sentences. The effects of learning on cue effectiveness were evaluated by comparing the error rates of experienced and inexperienced users. RESULTS: Unaided SSD participants (inexperienced users) performed as well as normal controls when tested without distracting sentences but produced significantly higher error rates when tested with distracting sentences. Most errors involved responding with coordinates that were contained in distracting sentences. This increased susceptibility to informational masking was significantly reduced when experienced IBC users were tested with the device. The listening advantage was most strongly correlated with the availability of voice pitch cues, although performance was also influenced by the location of distracting sentences. Directional asymmetries appear to be dictated by location-dependent cues that are derived from the distinctive transmission characteristics of IBC stimulation. Experienced users made better use of these cues than inexperienced users. CONCLUSIONS: These results suggest that informational masking is a significant source of communication impairment among individuals with SSD. Despite the lateralization of auditory function, unaided SSD subjects experience informational masking when distractors occur in either the deaf or normal spatial hemifield. Restoration of aural sensitivity in the deaf hemifield with an IBC enhances speech intelligibility under complex listening conditions, presumably by providing additional sound-segregation cues that are derived from voice pitch and spatial location. The optimal use of these cues is not immediate, but a significant listening advantage is observed after 3 months of unstructured use.

Cochlear implantation in older adults: long-term analysis of complications and device survival in a consecutive series.

OBJECTIVES: To analyze the postoperative complications associated with cochlear implant (CI) surgery in a large consecutive case series of older adults (≥ 60 yr). STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Approximately 445 individuals aged 60 years and older who received a first CI between 1999 and 2011. INTERVENTIONS: Cochlear implantation. MAIN OUTCOME MEASURE(S): Postoperative complications classified as major (meningitis, immediate postoperative facial weakness, device failure, flap dehiscence, and surgical removal) and minor (surgical site infection, balance problems, delayed postoperative facial weakness, and facial nerve stimulation). RESULTS: The mean age at implantation was 72.7 years (60-94.9 yr), and the median duration of follow-up was 4.8 years (0.1-12.5 yr). There were 42 minor complications in 41 patients (9.2%) and 36 major complications in 21 patients (4.7%). Seventeen patients (3.8%) required surgical device removal, 15 of whom underwent reimplantation. A Kaplan-Meier analysis of rates of device explantation demonstrated that at 5 and 10 years after CI, respectively, 95.4% and 93.1% of patients retained their original CI. When comparing complications between patients aged 60 to 74 years and those aged 75 years and older, there was a higher prevalence of balance problems lasting more than 1 month in the older group (9.5% versus 4.9%, p = 0.05). CONCLUSION: Our results indicate that the safety profile of cochlear implantation in an older population is comparable to that of younger adults and children. We suggest that concerns for increased postoperative complications in patients of advanced age do not need to be a primary consideration when determining CI candidacy.

Age-dependent cost-utility of pediatric cochlear implantation.

OBJECTIVES: Cochlear implantation (CI) has become the mainstay of treatment for children with severe-to-profound sensorineural hearing loss (SNHL). Yet, despite mounting evidence of the clinical benefits of early implantation, little data are available on the long-term societal benefits and comparative effectiveness of this procedure across various ages of implantation-a choice parameter for parents and clinicians with high prognostic value for clinical outcome. As such, the aim of the present study is to evaluate a model of the consequences of the timing of this intervention from a societal economic perspective. Average cost utility of pediatric CI by age at intervention will be analyzed. DESIGN: Prospective, longitudinal assessment of health utility and educational placement outcomes in 175 children recruited from six U.S. centers between November 2002 and December 2004, who had severe-to-profound SNHL onset within 1 year of age, underwent CI before 5 years of age, and had up to 6 years of postimplant follow-up that ended in November 2008 to December 2011. Costs of care were collected retrospectively and stratified by preoperative, operative, and postoperative expenditures. Incremental costs and benefits of implantation were compared among the three age groups and relative to a nonimplantation baseline. RESULTS: Children implanted at <18 months of age gained an average of 10.7 quality-adjusted life years (QALYs) over their projected lifetime as compared with 9.0 and 8.4 QALYs for those implanted between 18 and 36 months and at >36 months of age, respectively. Medical and surgical complication rates were not significantly different among the three age groups. In addition, mean lifetime costs of implantation were similar among the three groups, at approximately $2000/child/year (77.5-year life expectancy), yielding costs of $14,996, $17,849, and $19,173 per QALY for the youngest, middle, and oldest implant age groups, respectively. Full mainstream classroom integration rate was significantly higher in the youngest group at 81% as compared with 57 and 63% for the middle and oldest groups, respectively (p < 0.05) after 6 years of follow-up. After incorporating lifetime educational cost savings, CI led to net societal savings of $31,252, $10,217, and $6,680 for the youngest, middle, and oldest groups at CI, respectively, over the child's projected lifetime. CONCLUSIONS: Even without considering improvements in lifetime earnings, the overall cost-utility results indicate highly favorable ratios. Early (<18 months) intervention with CI was associated with greater and longer quality-of-life improvements, similar direct costs of implantation, and economically valuable improved classroom placement, without a greater incidence of medical and surgical complications when compared to CI at older ages.

Influence of implantation age on school-age language performance in pediatric cochlear implant users.

OBJECTIVE: This study examined specific spoken language abilities of 160 children with severe-to-profound sensorineural hearing loss followed prospectively 4, 5, or 6 years after cochlear implantation. STUDY SAMPLE: Ninety-eight children received implants before 2.5 years, and 62 children received implants between 2.5 and 5 years of age. DESIGN: Language was assessed using four subtests of the Comprehensive Assessment of Spoken Language (CASL). Standard scores were evaluated by contrasting age of implantation and follow-up test time. RESULTS: Children implanted under 2.5 years of age achieved higher standard scores than children with older ages of implantation for expressive vocabulary, expressive syntax, and pragmatic judgments. However, in both groups, some children performed more than two standard deviations below the standardization group mean, while some scored at or well above the mean. CONCLUSIONS: Younger ages of implantation are associated with higher levels of performance, while later ages of implantation are associated with higher probabilities of continued language delays, particularly within subdomains of grammar and pragmatics. Longitudinal data from this cohort study demonstrate that after 6 years of implant experience, there is large variability in language outcomes associated with modifiers of rates of language learning that differ as children with implants age.