Proceedings of the Annual Symposium of the American Cochlear Implant Alliance †

Speech and Language Development in ABI Candidates: Setting Expectations Lillian Henderson (with contributions from Holly F.B. Teagle, Shuman He, Craig A. Buchman, Matt Ewend) Introduction: A clinical trial of the use of the Cochlear Nucleus 24 Auditory Brainstem Implant (ABI) to demonstrate safety and efficacy for children who are unable to use a cochlear implant due to cochlear anatomy disorders has been undertaken at the University of North Carolina. A team approach to management is essential; team members include a neuro-otologist, a neurosurgeon, audiologists, speech-language pathologists and auditory physiologists. Inclusion criteria included normal cognitive abilities and the potential to develop spoken language. Five children have undergone surgery, had devices activated, and have used the devices for up to 2 years. Of the five subjects, two have CHARGE association, one has an absent cochlea (Michele Aplasia), and two have known cochlear nerve deficiency. Three of the children underwent cochlear implantation prior to receiving the ABI and two children continue to use a cochlear implant on the contra-lateral ear. Counseling parents on expectations for spoken language development through listening has been challenging given the limited long term experience with pediatric ABI as well as concomitant issues that negatively impact spoken language development in this population. Due to the uncertain prognosis for spoken language development through listening alone, it was advised that all recipients supplement with a visual communication system; one child uses Cued Speech, two use American Sign Language and two use Signed Exact English. Objective/methods: A repeated measures, single subject design has been used to quantify outcomes of individual children to describe intervention and rate of progress with ABI recipients relative to children with cochlear implants. For the purpose of comparison, speech and language data from UNC’s Childhood Development after Cochlear Implantation (CDaCI) population was used as a control group. Results: Each child is a case study with unique outcomes. All ABI users have reliable detection audiograms in the soundfield. Subjects 1 and 3 can identify duration, pitch and intensity cues, and multisyllable and mono-syllable words in a closed set listening activity. Although identification of familiar phrases has been addressed in therapy, identification of phrases through audition alone has been inconsistent. Subject 4 is 33% accurate with identification of word patterns and 16% accurate with identification of monosyllable words. Subjects 2 and 5 wear their device during all waking hours, but have not developed any discrimination or identification skills through listening at this time. All of the ABI recipients are able to vocalize on demand and change the pitch and duration patterns of their vocalizations. After 2 years of device use, early developing consonants and vowels are shown in 60% of this population. Table 1 Pediatric ABI performed at four US centers LA MEE NYU UNC Total Number 4 4 (5) 9 5 22 Previous CI 3 (1 bilateral) 0 4 3 10 Age at ABI 27–58 months 11–16 months 21 months–17 years 26–66 months 39± 26 Gender 2M and 2F 1M and 3F 2M and 7F 2M and 3F 7M and 15F Side 3R, 1L 3R, 1L 5R, 1L 3R, 2L 14R and 5L Etiology 3 CND 1 Michel 3 CND 1 Michel 4 CND 2 Michel 5 CND 2 CHARGE 1 CC 2 CND alone 15 of 19 CND eABR+ 4 of 4 4 of 4 9 of 9 4 of 5 21 of 22 Other CN stim 0 0 0 0 0 Complications 1 CSF leak 2 Device failures 1 CSF leak 1 CSF leak Aseptic meningitis 3 CSF leaks 1 meningitis 2 device Failures Sequelae None None None None None OR repeat stim 4 4 9 5 21–22 Aversive behavioral stimulation 1 of 4 Unsteady 0 of 4 4 of 9 Leg Leg, throat Chest Facial twitch 4 of 5 2 vestibular 1 cough 1 swallow 9 of 22 All de-mapped Outcome Resolved Resolved Resolved Resolved Resolved Proceedings of the Annual Symposium of the American Cochlear Implant Alliance Cochlear Implants International 2016 VOL. 17 NO. 5 216 All of the ABI recipients are developing language skills through the use of listening paired with a visual system such as Cued Speech or sign language. Conclusion: The ABI provides most children with sound awareness and increased potential to incorporate supra segmental cues for listening. Because the development of auditory skills is slow, language development must be supported by visual communication. Changes in vocal quality may indicate that spectral, intensity and temporal cues are being perceived through use of the ABI. Progress in auditory skills requires consistent, methodical and intensive therapy. Continued evaluation of this group of children is needed to understand the potential impact of ABI use on communication development. Cortical Auditory Event-Related Potentials in Patients with Auditory Brainstem Implants Shuman He The auditory brainstem implant has recently been used as a treatment option for children with either absent or abnormally small auditory nerves (e.g. Choi et al., 2011; Colletti et al., 2005, 2009; Nevison et al., 2002; Sennaroglu et al., 2011). The programming process in pediatric ABI patients can be very complicated and extremely challenging due to the lack of reliable behavioral responses. The long-term goal of our research is to develop objective tools to assist the programming process in patients with ABIs. In this study, we evaluated the feasibility of using electrically evoked auditory event-related potentials (eERPs) to optimize programming parameters in ABI patients. Specifically, we investigated the association between morphological characteristics of the eERP and nonauditory sensations evoked by electrical stimulation of the ABI. In addition, we assessed the test–retest reliability of eERPs in ABI patients. We also explored the feasibility of using the eERP to estimate the lowest stimulation level that ABI patients can detect for individual electrodes (i.e. T level). Study participants included five pediatric ABI users ranging in age between 2.8 and 10.2 years. These pediatric patients were implanted with ABIs due to cochlear nerve deficiency (CND). In addition, two adult ABI patients were included in this study. These two adult patients were diagnosed with neurofibromatosis II (NF2) and implanted with an ABI after a surgical removal of the tumors. The stimulus was a 100-ms biphasic charge-balanced pulse train. The speech processor was bypassed and the stimulus was directly delivered to individual electrodes. eERPs were recorded from multiple surface electrodes placed on the scalp using standard recording parameters. Our results showed that eERPs were recorded in both NF2 and non-NF2 patients with ABIs. Consistent with our previous study (He et al., 2015), two types of eERPs were recorded in these patients. The Type I response consisted of a single vertex-positive peak. In comparison, the Type II response showed complex waveforms and consisted of up to three groups of positive and negative peaks within a time window of 25–500 ms after stimulus onset. There was no consistent association between non-auditory sensations and the presence of Type I or Type II eERP responses in ABI patients tested in this study. However, the lack of association could be accounted by, at least partially, the lack of reliable behavioral responses and inability to discriminate auditory vs. non-auditory sensation in four pediatric ABI patients. Overall, eERPs in these ABI patients showed good test–retest reliability across test sessions. There was a robust correlation between T levels estimated using eERP measures and clinical behavioral testing procedure. Based on these results, we concluded that eERPs hold great promise to be used as a clinical tool to assist the programming process in ABI patients. However, further studies with more adult ABI patients are needed to evaluate the association between morphological characteristics of the eERP and non-auditory sensations in these patients. Details of this study and results will be reported in Ear and Hearing (He et al., 2015).