Study of the Nucleus 24 and ABI541 Auditory Brainstem Implants in Pediatric Non-Neurofibromatosis Type 2
Phase: NA
Conditions: Bilateral Hearing Loss for Causes Other Than Tumors
Sponsor: Massachusetts Eye and Ear Infirmary

 
 
 
 
 
 
Title: Study of the Nucleus 24 and ABI541 Auditory Brainstem Implant 
(ABI) in Pediatric Non-Neurofibromatosis Type 2 Subjects 
 
 
NCT: NCT01864291 
 
 
Protocol Date: IRB Approved 3/13/2016 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Overall Clinical Plan 
Study of the Nucleus 24 and ABI541 Auditory Brainstem Implant (ABI) in  
Pediatric Non-Neurofibromatosis Type 2 Subjects 
 
Study Objective: 
The purpose of this feasibility study is to demonstrate the safety and efficacy of the Nucleus 24 
and ABI541 Multichannel Auditory Brainstem Implant (ABI, Cochlear Corp, Sydney, AUS) in 
children who do not have the diagnosis of neurofibromatosis type 2 (NF2), and who have either 
experienced failed cochlear implantation (CI) or have been unable to receive a CI secondary to 
cochlear or cochlear nerve disorders. These conditions can include: developmental or acquired 
cochlear nerve deficiency (CND), cochlear aplasia (Michel), post-meningitis cochlear 
ossification, or cochlear malformation. This study proposes to implant up to 10 pre-linguistic 
young children (18 mos to 5 yrs. of age at time of implantation) and 5 post-linguistic children 
(<18 yrs of age) with the Nucleus 24 Multichannel ABI and Nucleus ABI541 in an attempt to 
demonstrate safety of the surgical procedure, tolerance of device stimulation, and the potential 
for auditory benefit beyond that experienced with their CI. This study will provide the 
preliminary experience for a larger scale clinical trial. 
 
Regulatory Status of the Investigational Device: 
Data supporting the safety and effectiveness of the Nucleus 24 ABI were provided to the United 
States Food and Drug Administration (FDA) in March 2000, as part of a Premarket Approval 
Application. On July 21, 2000, the Agency’s Ear, Nose and Throat (ENT) Advisory Panel 
unanimously recommended that FDA release the Nucleus 24 ABI for use by individuals with 
NF2 above the age of 11 years. Cochlear Americas subsequently received approval from the 
FDA in October 2000 (PMA No. P000015) for use of the ABI24 system in NF2 patients and 
provided a Right of Reference for our original IDE application (included in this supplement). 
 
The IDE Supplement for design change replaces the receiver / stimulator from the Nucleus 
ABI24M with the Nucleus ABI541.  Both ABI devices feature a multichannel electrode lead that 
terminates in twenty-one, 0.7 mm platinum disk-electrodes. The 21 platinum contacts are 
arranged on the surface of a silicone rubber pad in three rows of seven contacts and are 
surgically placed on the surface of the brainstem; specifically, on the surface of the cochlear 
nucleus. 
 
 
Background and Rationale: 
“Hearing impairment strikes at the very essence of being human, because it hinders 
communication with others” (1). Children born deaf (known as pre-linguistic deafness) have 
severe delays in speech and language acquisition that can retard their social and emotional 
development, influencing educational and career attainment (2). The pre-linguistic deafened 
child seldom develops significant understandable speech, and often has difficulty integrating into 
the hearing world (3). Thus, individuals with untreated congenital deafness often stay with a 
separate “Deaf community.” Hearing impairment negatively impacts upon educational 
attainment, employment opportunities, income, healthcare utilization, and life expectancy (1, 4-
15). As most deaf children are educated outside of the mainstream setting and ultimately achieve 
lesser levels of employment and income, lifetime losses for having untreated severe to profound 

hearing loss have been estimated at over $1 million dollars per child ($297,000 added 
expenditures) (16-18). By comparison, these lifetime costs are significantly higher than for near 
drowning ($98,500), accidents from firearms ($89,100), stroke ($129,200), rheumatoid arthritis 
($130,500), and epilepsy ($172,900), and are similar to those for the devastating illness of 
schizophrenia ($295,000). In addition to cost, deafness also contributes to an increased risk for 
depression, anxiety, and physical dysfunction (7, 8 19-21). In summary, untreated deafness is a 
major disability that negatively impacts upon all aspect of life. 
 
A cochlear implant (CI) is an auditory, neural stimulating prosthesis. These devices use a 
multiple electrode array that is inserted into the cochlea to electrically stimulate the auditory (i.e. 
cochlear) nerve in cases of severe to profound hearing loss. Using specialized speech processing 
and encoding strategies, these devices can restore sound awareness and significantly improve 
speech perception in both quiet and noise. Improved speech perception restores communication 
for adults and allows children to develop spoken language (22, 23). Thus, CIs alleviate many of 
the disabling effects of deafness described above. In addition to quality of life benefits, the cost-
utility of this intervention is positive for both adults and children (24, 25). 
 
The only absolute contraindication to CI is an absent cochlea or an absent cochlear nerve. In 
addition, patients at risk for lower levels of benefit from a cochlear implant include those with 
anatomic conditions that adversely affect the electrode-neural interface such as developmental 
labyrinthine malformations and cochlear ossification and fibrosis secondary to meningitis. While 
the diagnosis of cochlear (i.e. Michel) aplasia is clear clinically, the diagnosis of cochlear nerve 
aplasia is made somewhat more challenging by the spatial resolution of current imaging 
modalities (26-29). Because of this uncertainty, the term cochlear nerve deficiency (CND) was 
coined to refer to the situation where the cochlear nerve is small or absent on high resolution 
magnetic resonance imaging (MRI), or where the bony cochlear nerve aperture and canal are 
small or absent on temporal bone computed tomography (CT). The clinical diagnosis of CND 
includes these imaging findings in the setting of profound hearing loss (29, 30). Auditory 
brainstem response testing that shows unusual waveform morphology and sometimes only a 
cochlear microphonic can support the diagnosis (29). 
 
In an effort to provide hearing to deaf children who have inner ear malformations, CND, or 
ossification from meningitis, CI has been undertaken over the years (30). This might be 
considered the standard of care today for those who desire spoken language communication. 
Results of these interventions suggest that most children with CND gain some sound awareness 
from these devices using higher levels of electrical stimulation. However, achievement of open 
set speech perception for the purposes of speech and language development has been largely 
unsuccessful, probably as a result of a poor electrode-neural interface and other associated 
conditions (30-33). In a study from the University of North Carolina, only 19% of children with 
CND developed any open set speech perception using their CI, and none of these children were 
able to communicate using auditory-only information (i.e. all used some supplemental sign 
language). 
 
The ABI is an electronic device designed to convert environmental sounds into electrical 
impulses that are delivered along a multiple electrode array situated in close proximity to the 
cochlear nucleus in the brainstem. In a manner similar to the cochlear nerve, the cochlear nucleus 

maintains some degree of tonotopic arrangement; thus, application of discrete electrical 
stimulation along certain spatial locations within the lateral recess of the 4th ventricle results in 
discriminable psychophysical frequency percepts (i.e. pitch). The ABI is indicated for patients 
where the cochlear nerve is absent or unavailable for stimulation bilaterally. Most commonly, 
adults and children with hearing loss secondary to NF2 with bilateral acoustic (8th nerve) tumors 
have been the main group of patients implanted to date.  
 
In general, outcomes from ABI can be described in terms of sound detection and speech 
perception abilities using closed- and open-set test materials with and without the addition of lip-
reading. In a recent review of 86 NF2 patients implanted with ABIs, 13 did not respond to 
stimulation and 1 was explanted (34). Of the 60 patients with available 6-month data, mean 
open-set speech perception scores (CUNY sentences) using the implant alone, vision alone, and 
both the implant and vision on CUNY sentence were <10%, 30%, and nearly 55% correct. 
However, there was a wide range of auditory abilities, with some patients obtaining combined 
vision and sound scores of >90% correct (34). Thus, in patients with NF2, the ABI is an 
excellent enhancement to lip-reading. For individuals that have known only spoken language 
throughout their entire life, this connection to the speaking world is significant, and the 
importance of this communication enhancement should not be underestimated.  
 
International Experience with Auditory Brainstem Implantation in Patients without NF2: 
The effectiveness of ABI for patients without NF2 has only recently been explored (35-43). 
Colletti et al. in Verona, Italy, have summarized their results of a group of adult patients with a 
variety of conditions (excluding NF2) that received an ABI between 1997 and 2007 (40). Results 
were compared to a group of 34 individuals with NF2 implanted by the same surgeon. The 
duration of deafness ranged from 3.2 to 8.5 years (X = 5.1; SD = 2.4) for the NF2 group and 
ranged from 1.2 to 19.8 years (X = 9.6; SD = 5.9) for non-NF2 group. All non-NF2 patients were 
implanted through a retrosigmoid craniotomy. NF2 patients also required tumor removal prior to 
placement of the ABI. 
 
After at least one year of device use, using audition alone, sentence recognition ranged from 10 
to 100% (X  = 59%; Median = 53%; SD = 21.34) in the non-NF2 group (n = 48) and from 5 to 
31% (X  = 10%; Median = 16%; SD = 15.21) in the NF2 group (n = 32). These values were 
significantly better (p  = 0.0007) in the non-NF2 subgroup. Table 1 below, adapted from Colletti 
et al (2009), shows the sentence recognition score (type not specified) outcomes for the various 
etiologies without NF2 (40). Except for those adults with auditory neuropathy, sentence 
recognition scores in these adult patients are significantly better than in the patients with NF2. 

TABLE 1. Open-set sentence recognition 1-10 yrs. after ABI. 
 
 
 
 
 
Cause   
 
No. Subjects  Range,  
% X      SD  
  T versus NT  t test 
 
 
Head trauma       
        7   
32-80     
62  
  57  
      23,41            p = 0.005 
Auditory neuropathy          4   
12-18     
15  
  16  
       2,52             p = 0.07 
Cochlear malformations     6   
37-61     
44  
  61  
       11,2             p = 0.006 
Altered cochlear patency    31 
34-100  
60  
  64  
       19,81           p = 0.0048  
x-mean; Med-median, sd-standard deviation, T-tumor (NF2), NT-non-tumor 
 
 
 
 
 
 
Based on these results, the investigators concluded that adults with acquired conditions that are 
isolated to the cochlea or cochlear nerve such as otosclerosis (altered cochlear patency) and 
traumatic cochlear nerve avulsion are better candidates for ABI success than those individuals 
with NF2. They hypothesized that NF2 and/or its treatment results in pathological changes in the 
brainstem and cochlear nuclei that might preclude good performance with an ABI. Similarly, 
congenital malformations and auditory neuropathy might produce central nervous system 
changes that are not conducive to the development of open set speech perception using an ABI, 
possibly as a consequence of long-term auditory deprivation. 
 
In theory, children would be better candidates than adults for an ABI since they have substantial 
developmental plasticity and have no auditory memory that requires precise matching of signals. 
Colletti and colleagues in Verona, Italy, have placed ABIs in children without NF2 and have 
summarized their experience in 2008 (41). In that study, 26 children (17 in Verona; 9 in other 
countries) aged 14 months to 16 years received an ABI for different tumor and non-tumor 
diseases between 1996 and 2006. Etiologies included cochlear nerve aplasia with or without 
associated inner ear malformations (n=19), NF2 (n=2), incomplete cochlear partition (n=2), 
auditory neuropathy (n=1), post-meningitis ossification (n=1), and temporal bone fracture with 
nerve avulsion (n=1). Fourteen children had a variety of other disabilities including: mild motor 
delay (n=8), learning disability (n=7), behavioral impairment (n=7), cognitive delay (n=8), 
language delay (n=6), and 2 with visual impairment. Six children received previous CIs with no 
auditory results. All were operated through a retrosigmoid craniotomy, and there was one 
reported major complication (detailed below). Results showed that all children consistently use 
their devices (avg. 8 hrs./day) and demonstrated gradual improvement in communication skills, 
showing more attention and interest in school and at home. From an auditory perspective, 20 pre-
linguistic and 4 post-linguistic children have environmental sound awareness, detection of 
instrumental sounds and lip-reading enhancement; 3 pre-linguistic and 2 post-linguistic children 
achieved bi-syllabic word recognition as well as understanding of simple commands, but only 
one post-linguistic child had open set recognition (average 50% correct responses) and can 
perform the speech tracking test. Cognitive testing in a subset of 9 children using the ABI 
demonstrated improved selective visual-spatial attention (form completion subtest) and fluid 
(multisensory) reasoning (repeated patterns subtest) when compared to a group of 4 congenitally 
deaf children without an auditory assistive device. 
 
Sennaroglu et al. implanted 6 children with severe inner ear malformations using the Nucleus 24 
ABI. These children gained basic auditory function and were able to recognize and discriminate 
sounds such as the doorbell and telephone by the third month of usage. Two children had 
developed open set discrimination scores at that time (42). As of 2011, 21 children had received 
the same ABI for inner ear malformations in the same implant center in Turkey. No child has 

been unresponsive to implantation, and the number of active electrodes ranges from 8 to 20. Five 
children are reported to have variable degrees of open set speech perception (no details). When 
the pre- and post-operative linguistic gap (receptive and expressive) are compared, the majority 
had either decreased or stabilized the gap suggesting that ABI is effective in the language 
development of these children. Almost all children where the gap still increased in spite of ABI 
had additional handicaps. It was concluded that the presence of additional handicaps is the most 
important limiting factor in the language development of ABI in children with severe 
malformations (43). 
 
A child implanted in Verona was recently seen by our colleagues at the University of North 
Carolina at Chapel Hill (UNC) in 12/2009 for evaluation. He was reportedly implanted at 3 yrs. 
of age for CND with the Nucleus 24 Multichannel ABI through a retrosigmoid approach. His 
MRI and CT confirmed the anatomic findings and audiometric testing without his device 
revealed a profound hearing loss. Based on testing completed at UNC, after nearly 4 years of 
implant use (7 yrs. of age), the child scored 100% on an ESP-monosyllabic word test (12-choice, 
closed set pictures) and 81% and 48% on PBK phoneme and word scores (open set without 
visual cues), respectively.  Evaluation by UNC speech pathologists revealed that the child was a 
functional spoken language user in that he was able to produce complex sentence structure, 
although he did have some articulation errors that appeared to be related to oral-motor 
deficiencies. He could actively argue with his older brother in the exam room using oral 
language alone. 
 
In summary, the ABI appears to provide auditory awareness in all children. Emerging data 
suggest that some children without significant associated handicaps are beginning to develop 
open set speech perception and oral language. While further study is clearly needed, this 
approach appears promising for the limited subset of deaf children who cannot benefit from a CI. 
 
Complications from Auditory Brainstem Implantation: 
Complications related directly to the ABI have been unusual. Toh and Luxford indicated the 
most common complications in ABI surgery appear to be cerebrospinal fluid (CSF) leak, 
electrode migration, and non-auditory side effects during stimulation (44). Fatal complications 
are exceedingly rare. Laszig et al. reported one NF2 patient that died following tumor removal 
and ABI insertion as a result of pulmonary embolism and pneumonia (45). Grayelli et al. also 
reported one fatal embolism (46). These complications were more likely related to extended 
duration posterior fossa surgery rather than ABI surgery, specifically. Electrode migration 
appears to be a complication that occurs in patients undergoing ABI in the setting of tumor 
removal where distorted brainstem anatomy results in a shallow or deformed lateral recess. 
Following surgery, brain re-expansion might displace the electrode.  
 
CSF leaks are an expected risk from any surgery where CSF is encountered. Otto et al reported 2 
CSF leaks among 61 patients following translabyrinthine tumor removal and ABI placement that 
resolved with either a pressure dressing or a temporary lumbar subarachnoid drain (47). Grayelli 
et al. also reported 2 cases of CSF leaks after 31 ABI surgeries, and Sennaroglu et al. reported 
one case of a CSF leak in a child who underwent retrosigmoid ABI placement that resolved with 
wound exploration and repair of the air cell opening (42, 43).  
 

Colletti et al reported on 114 ABI operations performed through the retrosigmoid approach in 
Verona from 1997 to 2008 in 83 adults and 31 children (48). Thirty-six had NF2 (34 adults and 2 
children), and 78 (49 adults and 29 children) had cochlear or cochlear nerve disorders unrelated 
to NF2. Table 2 below details the complications from this study. There was a statistically lower 
risk for complications among the patients without NF2, presumably because there was no need 
for tumor removal prior to device placement. Importantly, there was 1 major complication in a 
child implanted in Manchester, England. That child developed a cerebellar contusion and 
swelling requiring a return to the operating room for clot evacuation. This child recovered 
without neurological sequelae.  
 
Other complications in children included wound seroma (n=4) that were managed with aspiration 
and bandage, minor wound erythema treated with antibiotics alone, and transient balance 
problems that resolved without treatment. 
 
Non-auditory side effects are a relatively common occurrence from ABI stimulation and are 
usually related to activation of the neural tissue in the region of the implant. Toh and Luxford 
reported non-auditory side effects in 42% of multichannel ABI users (44). Colletti et al (48) 
reported that ipsilateral body tingle was observed in 2 children (6.9%), facial nerve stimulation in 
2 (6.9 %), dizziness in 1 (3.4%), headache in 1 (3.4%), and throat tingle/tickle in 1 (3.4%) child. 
In adults, ipsilateral body tingle was observed in 10 subjects (8.7%: 7 NF2 and 3 non-tumor), 
facial nerve stimulation in 6 (5.2%: 4 NF2 and 2 non-tumor), dizziness in 15 (19%: 9 NF2 and 6 
non-tumor), headache in 5 (6 %: 3 NF2 and 2 non-tumor), and throat tingle/tickle in 8 (9.6%: 5 
NF2 and 3 non-tumor). These side effects are all alleviated with selective electrode deactivation. 
Re-activation of the offending electrode over time usually resolved the issue. 
 

TABLE 2. Complications in ABI patients. 
 
 
 
 
  
NF2 
 
Non-tumor 
 
 
 
 
 
Ad  
  
Ad  
Ch 
 
Major complications  
 
 
 
Mortality (unrelated to ABI) 3  
 
0  
0 
Cerebellar contusion   
1  
 
0  
1 
Permanent facial palsy  
1  
 
0  
0 
Meningitis  
 
 
1  
 
2a  
1a 
Lower cranial neuropathy 
2  
 
0 
0 
Hydrocephalus  
 
1  
 
1  
0 
Pseudomeningocele   
2  
 
0  
0 
Cerebrospinal fluid leakage  6  
 
1 
0 
 
Minor complications 
Transient hydrocephalus  
7  
 
1  
0 
Wound seroma  
 
4  
 
2  
4 
Minor infections  
 
2  
 
2  
1 
Balance problems  
 
11  
 
2  
1 
Infection around implant  
2  
 
2  
0 
Infection surgical flap  
2  
 
1  
0 
Transient facial palsy   
8  
 
0  
0 
Temporary dysphonia and  
difficulty in swallowing 
0  
 
0  
1 
Headache  
 
 
8  
 
3  
0 
Flap problems  
 
2  
 
0  
0 
  
Non-auditory side effects  
28  
 
16  
7 
 
 (a) Approximately 2 years after ABI activation. 
 Ad, adults; Ch, children. 
 
 
 
 
 
 
 
 
Benefits and Risks: 
The benefits and risks of ABI in children are listed in TABLE 3 based on a compilation of 
previous literature using the ABI in the proposed population, posterior fossa surgery in the 
literature, and the experience of children that have received cochlear implants for severe to 
profound hearing loss. The sections above detail the outcomes from the medical literature and 
the individual benefits and risks as well as others not previously mentioned are in the table 
below. 
 
Potential Benefits (see “International Experience with Auditory Brainstem Implantation in 
Patients without NF2” for literature review): 
Children receiving the ABI in the present study have a very realistic chance for gaining 
improved sound awareness, enhanced lip reading, and limited closed set speech (pattern 
perception) understanding with the device. This has been previously demonstrated for both 
adults (>18 yrs of age) with and without NF2 as well as for children (<18 yrs) without NF2.  In 
most instances, this will represent a significant improvement over that obtained using their CI. 
Higher levels of closed set (words) and open set speech understanding have been demonstrated 
in some adults and children using the ABI. As age of implantation and the presence of 

developmental and cognitive delays negatively impact upon a child’s ability to achieve this level 
of performance, the chances of this outcome for children in the present study remain unknown 
since most of those implanted in other parts of the world had these complicating, negative 
prognostic factors. This study will actively control for these variables by only implanting 
younger (18 mo to 5 yrs) pre-linguistic children without such delays or those that are post-
linguistic (< 18 yrs with previous open-set speech perception using a cochlear implant). As in CI, 
increased speech perception abilities can improve speech and language acquisition, educational 
achievement, employment opportunities and quality of life. These long-range benefits very much 
depend on the speech perception abilities of the child using the ABI device. If the device fails to 
provide sound awareness or improved speech understanding, then the remaining benefits are 
much less likely. 
 
 
TABLE 3. Potential Benefits and Risks of ABI  
Potential Benefits 
Potential Risks 
 Hearing: 
o Sound awareness 
o Speech perception 
 Sound awareness 
 Closed-set 
 Open-set 
o Music appreciation 
 Speech and Language Acquisition  
 Enhanced Communication 
o Oral 
o Improved lip-reading 
o Total 
 Educational Achievement 
 Employment Opportunities 
 Quality of Life 
 Reduced Costs secondary to: 
o Mainstream Education 
o Meaningful Employment 
 
 Vascular injury with  
o Bleeding,  
 Epidural hematoma 
 Subdural hematoma 
 Subarachnoid hemorrhage 
 Brain contusion,  
o Thrombosis 
 Ischemic stroke 
 Infection 
o Wound 
o Central nervous system 
 Meningitis  
 Cerebritis/Encephalitis 
 Epidural Abscess 
 Subdural empyema 
 Brain abscess 
o Device 
 Cranial nerve injury  
o Trigeminal nerve-facial numbness or pain 
o Facial nerve-paresis or paralysis  
o Cochlear nerve-hearing loss 
o Vestibular nerve-vertigo or imbalance 
o Glossopharyngeal/Vagus nerves-vocal fold 
paresis or paralysis, palatal paresis or 
paralysis, with resulting dysphagia, 
aspiration hoarseness 
o Spinal accessory nerve-shoulder 
dysfunction and winged scapula 
o Hypoglossal nerve-tongue deviation, 
dysarthria, and dysphagia 
 Cerebrospinal fluid disorder 

o Leakage (wound or rhinorrhea) 
o Pseudomeningocele formation 
o Hydrocephalus 
 Death 
 
 Non-auditory stimulation from the device 
o Facial pain or twitching 
o Throat tickle, spasm, or pain 
o Shoulder twitching 
o Hemibody tingle 
 
 Device Failure 
 
 
Potential Risks (see “Complications from Auditory Brainstem Implantation” for a literature 
review): 
Risks and complications from ABI surgery are expected to be uncommon but can potentially be 
serious. Majors complications such as bleeding in or around the brain including major cerebellar 
contusion should be very unlikely since extensive dissection, such as is undertaken in tumor 
surgery, will be unnecessary. In tumor surgery, the risk of major bleeding is well below 2%. In a 
large series (n=4400) from the literature of non-tumor posterior fossa craniotomies performed for 
microvascular decompression, the risk of cerebellar injury (parenchymal bleeding/contusion) 
was less the 1% and major other hemorrhage was much less common. Thus, the risk for 
intracranial hemorrhage and/or cerebellar injury with subsequent stroke is small. CSF leakage 
from the wound or from the nose (rhinorrhea) can also occur. This will likely be the most 
common surgical complication. Given the lack of need for internal auditory canal drilling (as in 
acoustic neuroma surgery); the leak risk will be well below 10% (that seen for acoustic neuroma 
surgery in the literature). In the microvascular decompression literature, the CSF leak rate is 
<2%. The etiology of rhinorrhea, should it occur, will also be very clear since internal auditory 
canal drilling is not required in this surgery. Rhinorrhea will arise from exposed mastoid air cells 
in the cranial opening. Similarly, the risk of cranial nerve injury will be unlikely since the 
anatomy will not be obscured by pathology such as tumors or infection. While cranial nerve 8 
and 9 border the lateral recess of the 4th ventricle (Foramen of Luschka), neural dissection will 
likely be mostly unnecessary and not obscured by tumor. Infection risk can include meningitis. 
This risk is less than 2% as a complication from craniotomy in the literature. The risk of device 
loss from infection is also very small.  
 
There are no published numbers in research journals for risks and complications in revision ABI 
surgery.  The types of risks are the same as in primary surgery.  Due to scarring from previous 
surgery, potential risks include injury to nerves during the removal of previous hardware with 
sharp dissection of fibrous scar tissue in proximity to lower cranial nerves, and CSF leak if 
inelastic collagen from scar tissue creates more difficulty approximating dura during closure.  
 
Non-auditory stimulation is expected to occur in roughly 20% of subject. Symptoms can include: 
facial pain or twitching, throat tickle, spasm, or pain, shoulder twitching, and hemibody tingle. 
Altering electrode maps and activation patterns can minimize or eliminate such stimulation. 

While not likely, there is the remote potential for large numbers of electrodes to require 
deactivation to the point that auditory stimulation will not be effective. Also, while not reported 
in this population, the theoretical possibility for cardiac arrest from stimulation along the lower 
cranial nerves.  
 
When balancing the benefits and risk of ABI surgery in children, there is no truly comparable 
surgical cohort for the population in question. However, when one considers microvascular 
decompression surgery for disorders such as trigeminal neuralgia and hemifacial spasm, the risks 
of ABI surgery are expectedly similar (and very low) and the potential benefits for the deaf child 
undergoing ABI far exceeds those benefits enjoyed by the vascular compression population. 
While facial pain and twitching are problematic for those with vascular compressive disorders, 
the impact of life-long deafness on a child are profound. As previously pointed out, children born 
deaf (i.e. pre-linguistic deafness) have severe delays in speech and language acquisition that can 
retard their social and emotional development, influencing educational and career attainment (2). 
The pre-linguistic deafened child seldom develops significant understandable speech, and is 
often socially stigmatized by those in the hearing world (3). Thus, individuals with untreated 
congenital deafness are often integrated into a separate “deaf community.” Hearing impairment 
negatively impacts upon educational attainment, employment opportunities, income, healthcare 
utilization, and life expectancy (1, 4-15). As most deaf children are educated outside of the 
mainstream setting and ultimately achieve lesser levels of employment and income, lifetime 
losses for having untreated severe to profound hearing loss have been estimated at over $1 
million dollars per child ($297,000 added expenditures) (16-18). 
 
Study Arm Overall Protocol: 
This IDE supplement is for the addition of a pediatric study arm to evaluate the early feasibility 
of the Nucleus ABI541 in children without NF2. It will be conducted as a repeated-measures, 
single subject experiment with up to 15 replications (i.e. 15 total subjects, consisting of 10 pre-
linguistic young children (18 mos. to 5 yrs. of age at time of implantation) and 5 post-linguistic 
children (<18 yrs. of age)). A single-subject research design was chosen (in which each subject 
serves as their own control) in order to accommodate the heterogeneity that is well known to 
characterize auditory prosthesis research. Post-operative evaluations will be conducted per our 
original study protocol at 1-2 weeks following surgery, initial activation (4-6 weeks post-
operatively), and 3, 6, 12, 18, 24, 30, 36, 42, 48, 54, and 60-month intervals post-activation. A 
60-month follow-up was chosen in an effort to demonstrate the emergence of open-set speech 
perception abilities prior to study cessation. Experience in the CI literature has shown that a 
minimum of 2 years of device usage is required for children with pre-lingual hearing impairment 
to develop some open-set speech perception abilities (50). Blinding or masking procedures are 
not included in the design, as the presence/absence of a brainstem implant cannot be easily 
concealed from the device recipients and/or clinical investigators.  
 
Preoperative measures will include high-resolution brain MRI, temporal bone CT and 
standardized, developmentally appropriate audiological and speech and language development 
test batteries. Children between 12 mo and 5 yrs of age with one of the anatomic conditions 
mentioned below and a present and patent cochlea and intact cochlear nerve will have previously 
received a CI as a precondition prior to consideration and will have demonstrated very limited to 
no benefit from the device based on a lack of development of significant closed set (more than 

pattern perception) or open set speech perception, and failure to achieve developmentally 
appropriate language growth during the follow up period. Those without a present or patent 
cochlea as well as those with hypoplasia or absence of the cochlear nerve will be implanted with 
the ABI without the need for previous CI. Post-linguistic children (<18 yrs) will have had a CI 
but lost or lacked benefit from an appropriate CI and have no potential for revision CI surgery to 
improve their condition. The side/ear contralateral to the previously placed CI will be chosen, 
unless this is not possible (eg. bilateral CIs), to avoid potentially same-side, unwanted surgical 
and processor interactions as well as to allow comparison of performance in the follow-up 
period. If ABI needs to be considered ipsilateral to the previous CI, removal of the CI will need 
to be considered. Surgical interaction would be the issue of needing to operate in and around the 
CI device putting it at risk of damage. Unwanted processor interactions would be problematic if 
the receiver stimulator of the previous CI and the ABI were located in the same region. The ABI 
processor headpiece might be attracted to the CI receiver stimulator.  
 
Following implantation of the investigational device and at least 4-6 weeks of healing, the ABI 
will be activated in a controlled setting and auditory performance assessed at the previously 
proposed intervals (3, 6, 12, 18, 24, 30, 36, 42, 48, 54, and 60 months). Subjects will be 
evaluated using the Nucleus Speech Processor and programmed with an approved sound 
processing strategy. Post-operative auditory function will be evaluated using behavioral 
audiometry and commonly used, developmentally appropriate measures of speech perception, 
speech production and language. Auditory function may also be assessed using 
electrophysiological tests such as such as electrically evoked auditory potentials, electrically 
evoked stapedial reflex testing and neural response testing at appropriate intervals. 
 
SPECIFIC AIMS OF PEDIATRIC STUDY ARM: 
Aim 1: Demonstrate the safety of ABI surgery in children. 
Aim 2: Demonstrate the development of sound awareness and improved speech 
understanding among children implanted with the ABI when compared to their baseline 
skills. 
Aim 3: Demonstrate the development of oral language skills following the use of the ABI 
that were not evident prior to its use. 
 
Subject Selection and Study Arm Design: 
Up to 10 pre-linguistic young children (18 mos to 5 yrs. of age at time of implantation) and 5 
post-linguistic children (<18 yrs of age) will be enrolled in the study at the sponsoring location. 
Qualified subjects must meet the following inclusion criteria and must not exhibit any of the 
exclusion criteria.  
 
Inclusion Criteria 
 Pre-linguistic hearing loss (birth-5 yrs.; age at ABI implantation 18 months-5yrs) with 
both: 
o MRI +/- CT evidence of one of the following:  
 Cochlear nerve deficiency  
 Cochlear aplasia or severe hypoplasia  
 Severe inner ear malformation 
 Post-meningitis ossification 

o When a cochlea is present and patent with a normally appearing cochlear nerve, lack 
of significant benefit from CI despite consistent use (>6 mo.) 
 No or limited speech perception ability (limited to pattern perception on 
closed set testing materials using the CI) 
 Lack of progress in auditory skills development 
 Post-linguistic hearing loss (<18 yrs. of age) with both: 
o Loss or lack of benefit from appropriate CI without the possibility for revision or 
contralateral implantation. Examples might include: 
 Post-meningitis ossification 
 Bilateral temporal bone fractures with cochlear nerve avulsion 
 Failed revision CI without benefit 
o Previously developed open set speech perception and auditory-oral language skills 
 No medical contraindications 
 Willing to receive the appropriate meningitis vaccinations 
 No or limited cognitive/developmental delays which would be expected to interfere with 
the child’s ability to cooperate in testing and/or programming of the device, in developing 
speech and oral language, or which would make an implant and subsequent emphasis on 
aural/oral communication not in the child’s best interest 
 Strong family support including language proficiency of the parent(s) in the child’s 
primary mode of communication as well as written and spoken English. 
 Reasonable expectations from parents including a thorough understanding:  
o of potential benefits and limitations of ABI    
o of parental role in rehabilitation 
o that the child may not develop spoken language as a primary communication mode or 
even sufficient spoken language to make significant academic progress in an 
aural/oral environment 
 Involvement in an educational program that emphasizes development of auditory skills 
with or without the use of supplementary visual communication. 
 Able to comply with study requirements including travel to investigation sites and clinic 
visits.  
 Informed consent for the procedure from the child’s parents/legal guardian. 
 
Rationale for age ranges in pre-linguistic hearing loss:  
18 months of age (at time of implantation) was chosen for the lower age limit to minimize the 
adverse effects of auditory deprivation on speech perception, speech production, and language 
development (23, 50). Moreover, 18 months of age will allow for a child to receive a CI at 1 year 
of age and have at least 6 months of device experience prior to considering ABI. Six months of 
CI usage prior to ABI consideration was chosen as this time period to allow for clear 
demonstration of lack of benefit as defined as either: (1) lack of sound awareness, or (2) where 
elevated charge requirements, absent ECAPs, elevated pure tone averages (>45 dB), and no or 
limited speech perception abilities are evident. To determine if a child is making significant 
progress both subjective and objective measures are used. Objectively, standardized speech 
perception, production, and language tests (as described below) are administered to determine if 
standard scores are following typical developmental patterns, even at a reduced rate. No or 
limited speech perception abilities will be considered when there are no improvement in IT-
MAIS, or ESP measures from preop measures at the 6 month post-CI interval (30, 50). 

Developmental norms are also determined based on the hearing age. For example, a child who is 
9 months old receptively understands between 3 and 50 vocabulary words and approximately 
300 between the ages of 2 and 3. Does the child with a hearing age of 9 months understand this 
many words? For early speech development, all English vowels should be present by a hearing 
age of 12 months. Children 18 months of age can be tested using the standardized measures to 
determine progress. 
 
From a surgical perspective, 18 months of age is a sufficient size and weight in most instances to 
consider ABI surgery. Factors that increase the anesthetic risk (particularly cardiac arrest) among 
children undergoing surgery include: age<1 yr, obesity, other associated co-morbidities, ASA-PS 
>3, emergency surgery. Moreover, children undergoing elective surgery should be free of upper 
respiratory tract infection to reduce the risk of respiratory tract complication. Importantly, it is 
currently standard practice to undertake CI between 1 and 2 years of age. The risk for anesthetic-
related complications will be no different for this proposed group of children undergoing ABI 
surgery (58). While not specifically studied, the risk of major blood loss from ABI surgery is 
relatively small since tumor resection is not needed. If Chiari posterior fossa decompression 
surgery among children serves as a surrogate for blood loss risk in this population, a recent meta-
analysis suggested only 1 of 246 children experienced any bleeding related complication from 
this type of surgery (59). As stated below, children with any medical co-morbidities that place 
them at an increased risk for complication will be avoided in this trial.    
 
Exclusion Criteria 
 Pre- or post-linguistic child currently making significant progress with CI – This will be 
considered if a child is progressing along the expected speech reception hierarchy (SRI-Q) 
as detailed by Wang et al (50).  Even for the very young children (18 months of age with 6 
months of use), nearly all children with a good auditory signal from their CI will have 
reached ceiling effects on the IT-MAIS and have pattern perception beyond chance using 
the ESP (50). Moreover, there will evidence of improvement in these metrics over time. 
 MRI evidence of one of the following:  
o normal cochlea and cochlear nerves or NF2 
o brainstem or cortical anomaly that makes implantation unfeasible 
 Clear surgical reason for poor CI performance that can be remediated with revision CI or 
contralateral surgery rather than ABI.  
 Intractable seizures or progressive, deteriorating neurological disorder  
 Unable to participate in behavioral testing and mapping with their CI. If this appears to be 
an age effect, ABI will be delayed until we can be assured that the child will be able to 
participate, as reliable objective measures of mapping are currently not available for 
mapping these devices.  
 Lack of potential for spoken language development. This will be considered the case when 
evidence of the following exist: 
o Severe psychomotor retardation, autism, cerebral palsy, or developmental delays 
beyond speech that would preclude usage of the device and oral educational 
development. Autism is a special case where there is the potential for delayed 
presentation. When early signs are considered present, we will request a 
comprehensive developmental assessment for further evaluation prior to considering 
routine evaluation. 

 Unable to tolerate general anesthesia (cardiac, pulmonary, bleeding diathesis, etc.). 
 Need for brainstem irradiation 
 Unrealistic expectations on the part of the subject/family regarding the possible benefits, 
risks and limitations that are inherent to the procedure and prosthetic device. 
 Unwilling to sign the informed consent. 
 Unwilling to make necessary follow-up appointments. 
 
Device 
Subjects will be implanted with the investigational device, the Nucleus ABI541, and fitted with 
an approved Nucleus speech processor (Cochlear Corp, Sydney, AUS). 
 
Procedures 
All subjects will have the study visits outlined in our original IDE application: Pre-operative 
visit(s), surgical implantation and hospitalization, post-operative follow-up at 1-2 weeks, initial 
activation (4-6 weeks post-implantation), 3, 6, 12 18, 24, 30, 36, 42, 48, 54, and 60 month visits. 
The surgical implantation and post-operative care (hospitalization) will be carried out at 
Massachusetts General Hospital. The remainder of the protocol including screening, consent, 
enrollment, and post-operative activation, testing, and follow-up will occur at Massachusetts Eye 
and Ear Infirmary. The following procedures will be carried out at the appropriate interval visits 
(see Schedule of Events). 
 
Screening, Informed Consent, and Enrollment 
Patients will come from either the Massachusetts Eye and Ear otology clinic, pediatric CI 
practices (more than several hundred new patients/yr.), or by referral from outside institutions. It 
is anticipated that potential subjects from outside the institution will hear about the study through 
discussion among colleagues. The records of the MEEI children currently in our clinics and 
known to have cochlear or cochlear nerve disorders that would make them potential ABI 
recipients will be reviewed by the principal investigator to identify their potential candidacy for 
ABI surgery. Children with such disorders are currently tracked as a part of the principal 
investigator’s secure patient list. During a routine patient visit, general interest in the study will 
be discussed in private. Should there be general interest, a detailed (~1 hr.) discussion will be 
scheduled to go through the entire protocol and consider informed consent. For those subjects 
that are not patients of the principal investigator, a knowledgeable individual will provide the 
subject with information and contact details of the investigator. The prospective subject can then 
initiate contact, if desired. There are no criteria that limit access among women or minorities. 
The requirement for participants to be primary English speaking families will limit access among 
non-English speaking individuals. This is a precondition because the investigators must be able 
to administer and judge speech and language test results that are English only in nature. This also 
allows for analysis among similar types of tests materials. Given the small number of 
participants, this is an unavoidable precondition.  
 
The Principal Investigator will inform the parent or guardian about all aspects of the study for 
implantation of the Nucleus ABI541 including: study expectations and requirements, surgical 
procedure, and the postoperative evaluations and schedule. The risks of surgery and activation 
will be explained to the parent or guardian as outlined in the Institutional Review Board (IRB)-

approved Informed Consent Form. The potential limitations and advantages of implantation with 
the Nucleus ABI541 shall also be explained.  
 
The parent or guardian will be given the opportunity to ask questions about the procedures, 
Informed Consent Forms and the study details prior to signing the Informed Consent Form. The 
parent or guardian will then be given a copy of the signed Informed Consent Form. For children 
old enough to participate in the process (typically 7 yrs. and older) of informed consent, they will 
also be given an appropriate assent form to read and sign as deemed appropriate. Following 
informed consent, Inclusion/Exclusion criteria will be considered for the prospective subject. If 
the subject meets criteria, enrollment will continue. 
 
Medical History and Physical Examination 
This is a standard part of routine medical care. This will include a detailed evaluation as outlined 
by Buchman et al (49). Additional components unique to this evaluation will include: hearing 
history, CI history, medical/surgical history, vaccination history, social history, and physical 
examination. Review of appropriate audiometric and imaging studies will be conducted. The 
reasons for seeking these pieces of information are detailed below and listed in the Inclusion and 
Exclusion section above. 
 
Hearing history: Newborn infant hearing screening results, diagnostic auditory brainstem 
response testing results, as well as etiology, onset, duration, severity, and duration of 
profound hearing loss will be sought and recorded. The hearing history might identify 
issues relevant to understanding the etiology of the child’s hearing loss. As an example, 
children with evidence of passing the newborn infant screening and progressive hearing 
loss might have a degenerative neurological disorder rather than congenital hearing loss. 
This would be considered a contraindication to implantation (see exclusions). On the 
other hand, a pass on the newborn infant hearing exam using otoacoustic emissions and 
present cochlear microphonic on ABR would be consistent with cochlear nerve 
deficiency. Another important issue might be if a child had normal hearing and 
development prior to meningitis would be important for understanding the onset and 
duration of hearing loss.  
 
CI history: Date and hospital of implantation, ear implanted, device type, number of 
electrodes implanted in the cochlea and activated, duration of use, parental subjective 
assessment of performance and aversive reactions, date of explantation and reason (if 
applicable). Understanding these issues are extremely important for better assessing 
whether the reason for poor performance with a CI is related to the surgical procedure, a 
potential device abnormality, or the underlying disorder. Potentially, a child with a 
surgical reason for poor performance might be counseled to consider revision or 
contralateral CI rather than ABI. 
 
Medical/Surgical history: This will include a comprehensive review of medical 
conditions (cardiac, pulmonary, renal, neurological, metabolic, etc.) that are known to 
contraindicate major surgery as well as use of the implant (see Exclusions above). 
Previous surgical history including anesthetic history, details of CI surgery, and 

complications will be reviewed. A detailed review of systems will also be carried out and 
recorded. 
 
Vaccination history: The vaccination history will be carefully reviewed to assure 
compliance with the recommendations of the Centers for Disease Control (CDC) and the 
United States Food and Drug Administration (FDA) for individuals with CIs 
(http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5909a2.htm).  
 
Social history: A detailed social history will seek information regarding the parental 
support, educational and home environment. Specifically, issues related to parental 
ability to comply with the therapeutic and follow-up expectations of the protocol. This 
includes the parent’s commitment to developing audition skills for their child as a 
component of their communication strategy.  
 
Physical examination: A thorough physical examination with particular focus on the 
details of the head and neck, cardiac, pulmonary, and neurological systems will be carried 
out. CI sites as well as other surgical sites in the head and neck will be assessed. Ongoing 
otitis media will be identified and treated as needed. 
 
Imaging 
The imaging protocols and diagnostic criteria for the various inner ear malformations and CND 
are regularly used in our institution and will be considered as previously described (27-30, 49). 
These will include both MRI and CT imaging. For children with a previous CI, the safety and 
need for MRI will be carefully considered. If previous MRI has been obtained and are of 
adequate quality, these will be sufficient. If the internal auditory canals (IACs) are very narrow 
on previous MRI or CT, MRI may also not be needed. If the diagnosis of CND is in question or 
the brain morphology is has not been adequately assessed, CI magnet removal will be considered 
prior to scanning. The imaging protocols will include: 
 
 MRI using a dedicated pediatric vestibulocochlear nerve protocol – For young 
children, this may require general anesthesia. The protocol includes axial and sagittal 
unenhanced T1-weighted images, axial T2-weighted images, and axial fluid-attenuated 
inversion recovery images through the entire brain, as well as high-resolution 3D CISS 
images through the temporal bones. Parameters for the CISS sequence vary by scanner. 
In most cases, patients will be scanned under conscious sedation or general anesthesia. 
Total scanning time for each examination is approximately 20 minutes. The temporal 
bone sequences are reconstructed in the axial plane as well as in an oblique sagittal plane 
oriented perpendicular to the long axis of each IAC for viewing. 
 CT imaging protocol – High resolution temporal bone CT scans will be performed on 
CT scanner to generate contiguous direct sequential axial and coronal images which are 
acquired through the temporal bones at a thickness of 0.6 or 0.75 mm.  
 
All MRI and CT images will be reviewed on a clinical picture archiving and communication 
system (IMPAX 5.0; AGFA, Ridgefield Park, NJ, USA). All quantitative measurements are 
made using the standard ruler tool included in our picture archiving and communication system 
software package. Of note, our institution has numerous world-renowned head and neck 

radiologists including Dr. Hugh Curtin, who have tremendous familiarity and expertise with 
disorders of the inner ear, cochlear nerve, and abnormal anatomy due to prior surgery or trauma. 
 
Audiologic Assessment  
Pre- and Post-operative Behavioral audiometry and speech perception testing. The standard 
clinical CI speech perception and speech and language test battery will be used.  This testing is in 
common use every day in our clinics. Tests will be presented in a sound-controlled sound booth 
using monitored live voice (50 dB HL) in the auditory only condition or recorded materials (60 
dB SPL). These tests include:  
 
 Detection audiogram, aided and unaided individual ears 
 IT-MAIS or MAIS 
 LING 6 sound test (MLV) 
 ESP Low Verbal or Standard-Recorded if possible or MLV @ 60dB HL 
 PB-k words and phonemes- Recorded @ 60dB HL 
 CNC- 50 words @ 65dB SPL 
 
Standard audiometric techniques will be performed for measuring sensitivity to sound with the 
ABI activated. Visual reinforcement audiometry will be performed to measure sound field 
thresholds up until the child is 30 to 36 months of age. Conditioned play audiometry will be 
performed when the child is approximately 30 to 36 months of age and older. Stimuli will be 
delivered via loudspeaker in the auditory only mode consisting of live-voice speech and warbled 
tones or narrow-band noise for 250, 500, 1000, 2000, 4000, and 6000 Hz. These tests will be 
used to document profound hearing loss preoperatively as well as the level of sound detection 
using the device in the post-operative period.  
 
The following speech perception measures are routinely used with CI recipients and represent a 
hierarchy in both the child's required response and the difficulty of test material.  When a child is 
not able to participate in structured testing for any reason including age, attention, or level of 
auditory development, then a parental questionnaire is used (IT-MAIS or MAIS).  The earliest 
developmental response format is detection and imitation (LING 6-sound test), followed by a 
small (4 items) closed-set format (ESP-low-verbal) and then a larger (12 items) closed-set format 
(ESP standard).  Open set speech recognition follows (PB-k, CNC).   Each child will be assessed 
starting with the lowest level of the battery at each assessment interval until a 100% score is 
achieved at 2 consecutive test intervals.  Criteria for moving on to the next test are based on the 
child's developmental (behavioral and auditory) skills, not chronological or hearing age. 
 
Meaningful Auditory Integration of Sound (MAIS) and Infant-Toddler Meaningful 
Auditory Integration of Sound (IT-MAIS) (51, 52). The MAIS is a 10-item parent-report 
scale designed to evaluate developing auditory behavior in children ages 4 years and 
older. Parents rate how often their child engages in specific behaviors with regard to their 
child’s bonding with the sensory device, auditory awareness, and the ability to derive 
meaning from sound. The IT-MAIS was developed for children younger than 4 years. 
While it shares the majority of questions with the MAIS, the IT-MAIS additionally 
explores vocal behavior of infants with their sensory device. The MAIS probes ten 
questions in a structured parent interview, assessing the child’s bonding with the sensory 

device, auditory awareness, and ability to derive meaning from sound in everyday 
situations.  
 
Ling Six Sound Test (Ling, 2002/2003). The Ling Six Sound Test samples the child’s 
ability to detect and identify speech sounds representative of the speech frequency 
spectrum (ah, oo, ee, sh, s, m). The test is administered live-voice.  
 
Early Speech Perception (ESP) Test (53). The ESP is designed to assess pattern 
perception (differentiation of syllable number and stress pattern), spondaic word 
identification (two syllable word with equal stress on each syllable), and monosyllabic 
word identification in a closed-set.  Attainment of a criterion level is required to pass 
each sub-test. This test is generally introduced when the child is 2 years of age or when 
he or she is able to choose between two alternatives. There is a standard version and a 
low-verbal version. Stimuli for both versions are typically presented live voice. 
 
Phonetically Balanced Kindergarten Word Test (PB-k) (54). The PB-k is an open-set test 
of 50 words that are meant to represent the distribution of phonemes in English using 
kindergarten level vocabulary.  The child repeats the word and his responses are scored 
for the correct word and number of phonemes repeated.  This will be presented in a 
monitored live voice mode. 
 
Consonant- Nucleus-Consonant Word Test (CNC) (55).  The CNC is an open-set test 
which includes 10 lists of 50 words recorded by a male speaker. This test was developed 
to provide lists of monosyllabic words with equal phonemic distribution across lists with 
each list exhibiting approximately the same phonemic distribution as the English 
language.  
 
Speech and Language Assessment  
Communication mode and educational setting are identified and recorded by the managing 
audiologist and/or speech pathologist at our institution. The following tests will be administered 
in their standardized forms. The raw scores will be used to compare children to their 
chronologically aged peers with typical hearing to determine standard scores by following testing 
protocols. Results will be discussed using comparative measures to the subject's hearing age with 
the ABI as well. Our protocol for speech-language evaluations is well established for our 
population with CIs. This same protocol will be used to effectively assess children's spoken 
language development with an ABI. There is one dedicated speech pathologist on the pediatric 
CI team with extensive experience using these measures in children within the proposed age 
range. The standard clinical test battery includes: 
 
MacArthur-Bates Communicative Development Inventories (CDIs) (56). CDIs are parent-
report instruments designed to evaluate early receptive and expressive language skills in 
children. The CDI/Words and Gestures assess vocabulary comprehension, production and 
the use of gestures typically used by children in the 8-to-18 month age range. The 
CDI/Words and Sentences extend the list of vocabulary words and probe a number of 
aspects of grammatical development typically acquired by 30 months of age.  
 

Pre-School Language Scale, Fourth Edition (PLS-5) (Zimmerman, Steiner, & Pond, 
2010).  The PLS-5 is a standardized language test designed for infants and young 
children.  The Auditory Comprehension subscale targets skills known to precede 
language development, including: attention to speakers, appropriate object play, basic 
vocabulary, concepts, grammatical markers, and complex sentences.  The Expressive 
Communication subscale assesses vocal development, social communication, naming of 
common objects, phonological awareness, sequencing skills, as well as use of concepts, 
prepositions, grammatical markers, and varying sentence structures.   
 
Clinical Evaluation of Language Fundamentals Preschool, Second Edition (CELF-P2 ) 
(Semel, Wiig & Secord, 2003).  The CELF-P2 assesses the comprehension and 
expression of language of children 3 to 6 years of age.  This test examines an individual’s 
ability to understand and produce connected language looking specifically at vocabulary, 
grammar, pragmatic function and higher order structures of language. 
 
Clinical Evaluation of Language Fundamentals, Fourth Edition (CELF-4) (Semel, Wiig 
& Secord, 2002).  The OWLS CELF-4 assesses the comprehension and expression of 
language of children 5 to 21 years of age.  This test examines an individual’s ability to 
understand and produce connected language looking specifically at vocabulary, grammar, 
pragmatic function and higher order structures of language. 
 
Goldman-Fristoe Test of Articulation. (Goldman-Fristoe, 1986).This test assesses a 
child's articulation ability by sampling both spontaneous and imitative speech production. 
Pictures and verbal cues are used to elicit single word answers that demonstrate common 
speech sounds. The Goldman-Fristoe measures the articulation of speech sounds and 
identifies and describes the types of articulation errors produced by the child. 
 
Surgery  
Nucleus Multichannel ABI will be placed using a craniotomy on the side opposite the child’s 
previous CI (if present) and assuming there are no obvious contraindications. This approach 
provides direct access to the lateral recess of the 4th ventricle and region of the cochlear nucleus. 
This approach has previously been documented to be safe in the literature for this use (48) and 
has been used extensively in adults and children at our institution for other causes. Our team has 
extensive experience with cerebellopontine angle surgery (i.e. the region of interest). We have 
carried out numerous cerebellopontine angle craniotomies for acoustic neuromas, and we have 
regularly used the retrosigmoid approach in both adults and children. We have also carried out 
the retrosigmoid approach for ABI placement in four adult cases with NF2 and recently 
completed our first ABI surgery in a non-NF2 adult. Of note, Dr. Lee has been actively training 
with Dr. Colletti and Dr. Sennaroglu through multiple visits to Italy as well as a hosted visit to 
MEEI, respectively, to further improve his own expertise and familiarity with the retrosigmoid 
approach for ABI surgery in non-NF2 patients, including children. He has observed and 
scrubbed in on over ten cases of pediatric / infant ABI surgeries with Professor Colletti in 
Verona, Italy. 
 
ABI surgery is carried out under general endotracheal anesthesia, without paralytic agents, and is 
administered by a dedicated pediatric anesthesiologist in the operating room. The child will have 

2 large bore intravenous catheters placed. Following induction, the child will be maintained 
under normotensive anesthesia using a combination of inhalational and intravenous agents. We 
plan to conduct intraoperative monitoring of CN VII and IX to minimize the risk of injury to 
these nerves. The patient will be positioned in a modified lateral position to expose the 
suboccipital cranial region.  
 
The remainder of our surgical protocol will be unchanged from adult patients described in our 
original IDE application. Briefly, we will utilize a translabyrinthine or retrosigmoid approach, 
depending on the anatomical and patient specific factors, to obtain access to the cochlear nucleus 
of the auditory brainstem. In particular, patients with prior dysfunction of the facial nerve will 
primarily undergo a translabyrinthine approach, while patients with preserved facial nerve 
function will undergo a retrosigmoid approach for ABI surgery. 
 
In the scenario that a revision surgery is performed on the same side, there are additional steps 
for explantation of the previous device.  Incision and exposure will extend over the location of 
identified existing hardware.  The previous receiver-stimulator will be clipped free from 
stimulating and ground wires, and removed from the fibrous enclosure over the temporoparietal 
area.  The ground wire is dissected out and removed, and stimulator wire will be followed to site 
of previous craniotomy, through dura, and all the way to the foramen of Luschka using sharp 
dissection of fibrous scar tissue.  Once the stimulator wire has been skeletonized, the device is 
explanted.  Once the previous hardware is removed, the procedure continues with new ABI 
placement. 
 
The electrode array of the ABI will then be placed and tested intra-operatively using electrically-
evoked Auditory Brainstem Responses (eABRs). All intraoperative and post-operative testing 
will occur within the approved safety limits for stimulation parameters of the Nucleus ABI541 
Auditory Brainstem device. Intraoperative recordings will be carefully saved to allow for 
correlations to be made with audiologic outcomes after device activation. If testing does not 
reveal responses, exploration will be undertaken to again confirm location. After confirming 
optimal electrode array placement, the array will be anchored in place by overlaying soft tissue, 
thereby minimizing the risks of lead migration and device extrusion. After placement of the 
array, the receiver will then be within the temporal bone posterior to the pinna. The patients 
overlying subcutaneous tissue and skin will then be closed and covered with dressings using 
standard surgical techniques. 
 
Postoperative Care  
Following surgery, the child will be admitted to a specialized pediatric intensive care unit 
(PICU) at Massachusetts General Hospital. The unit is staffed full time by pediatric intensive 
care specialists with expertise and experience in pediatric neuro-intensive surgical care. The 
child is monitored continuously using both invasive and non-invasive methods as needed. These 
may include an arterial line, central venous pressure (CVP) line, urinary catheter, blood pressure, 
pulse oximetry, EKG, and continuous nursing observation. It is anticipated that the child’s 
endotracheal tube will be removed early in the postoperative period, either in the operating room 
or while in the PICU. Ventilator support as well as pain control and adequacy of sedation will be 
closely monitored while an endotracheal tube is indwelling. Intravenous antibiotics will be 
administered for no more than 24 hours following surgery in accordance with current 

recommendations from the American Association of Neurological Surgeons (AANS) and the 
American College of Surgeons (ACS).  The pharmacy will be consulted for specific dosing 
based on the patient’s weight. Corticosteroids will be administered for approximately 2 weeks or 
less following the surgery to minimize any brain swelling. Pain medication will be given 
prophylactically early on and as needed in the post-operative period. A CT scan will be obtained 
on the first postoperative night to evaluate for brain swelling and electrode array location. The 
patient will be encouraged to ambulate with the diet advanced on the first postoperative day as 
tolerated. Intravenous fluids are weaned as oral intake increases. 
 
The child is discharged from the PICU to a standard pediatric surgical floor no sooner than 
postoperative day 1 (day after surgery) or later as medically indicated. De-intensification 
includes removal of the urinary catheter, and discontinuation of continuous EKG and oximetry 
monitoring. On day 3 following surgery, the incision will be examined for CSF leakage. In the 
absence of a leak, the child will be discharged home with instructions for the parents to follow-
up in one week as an outpatient. Appropriate phone numbers are provided for the clinics, 
hospital, and emergency department as well as details that should prompt the family to return to 
the hospital. These would include: increasing pain, swelling, nausea, vomiting, fever, shortness 
of breath, rapid breathing, changes in mental status, or anything that concerns the parents.  
 
Should the child develop CSF leakage from the wound, over-sewing will be carried out as a 
sterile procedure. Should the child develop rhinorrhea, surgical re-exploration of the wound or 
lumbar subarachnoid drainage will be undertaken depending on the age and cooperativeness of 
the child and the presence and violation of the mastoid air cells that were observed at the time of 
surgery. 
 
In the scenario that a child has a moderate to significant fall risk, the use of a soft helmet for 
safety is recommended in children. These cases would include active children who are still 
learning to ambulate, and children who have persistent incoordination or gait instability.  A 
helmet prevents potential injury to children with auditory implants that are placed above and 
behind the ear and against the skull, and reduces the risk of device failure as a result of the 
impact from falls or collisions.  Assessment of a child’s balance, coordination, and fall risk is 
made by the multidisciplinary implant team.  The frequency of use and age at which helmets 
would be recommended is determined on a case-by-case basis.  Any soft helmet that fits the 
child’s head comfortably and is certified by the Consumer Product Safety Improvement Act 
(CPSIA) will be adequate. 
 
 
Initial Activation and Follow Up Testing 
At the initial stimulation and at subsequent device programming sessions, a combination of 
objective data and behavioral methods will be used to program the speech processors.  Data 
gathered from intra-operative electrophysiological testing that identified electrodes with optimal 
responses to stimulation would be selected for inclusion in the speech processor program. As 
with the initial stimulation of CIs in young children, behavioral observation and conditioned 
behavioral audiometry techniques will be used to determine electrical thresholds and comfortable 
listening levels. The initial stimulation will include pediatric anesthesia support. Starting with 
electrode pairs that elicited the best, evoked responses in the OR, stimulation will commence in a 

conservative fashion, using an ascending approach, until a behavioral response is observed.  It 
will be documented when stimulation awareness is observed. Depending on the child’s level of 
cooperation, conditioning of that response will ensue. During the initial stimulation and 
subsequent programming sessions, the child will be trained to participate in device setting.  If 
stimulation levels result in visible or aversive responses (facial contraction, throat tickle, cough, 
shoulder activation, extremity sensations) higher stimulation levels will not be attempted. 
Although young children who have no auditory experience are limited in their ability to provide 
feedback about stimulation, our team of pediatric CI audiologists has extensive experience in 
monitoring behaviors and interpreting responses to auditory electrical stimulation from children 
as young as 11 months of age.  It is anticipated that the programming of the speech processor for 
the ABI will be similar in practice to programming CIs using a progressive mapping approach 
which includes making incremental changes to current levels over time, allowing for comfortable 
adaptation to sound.  Only programs that have been stimulated in the clinic will be programmed 
to the user speech processor. The children will be seen at the designated follow up appointments 
for device programming at 1 week post initial activation and at 3, 6, 12, 18, 24, 30, 36, 42, 48, 
54, and 60 months for mapping and assessment including behavioral audiometry and speech 
perception testing. A language assessment will be repeated at 6-month intervals. 
 
The investigator will plan to communicate regularly with the subjects local physician(s) to assess 
how the subject is doing. The investigator will also collect health information from these 
providers that may be useful in evaluating the safety and effectiveness of the ABI. The duration 
of this collection will be from the time the subject is enrolled until the study is complete. 
Information about this activity is included in the parental permission form. It is also expected 
that each provider will obtain individual authorization from the patient’s parents for this purpose. 
The investigator will request that a copy of the signed authorization be sent for storage with the 
subject’s case history. All health information will be transmitted in a secure manner in 
accordance with MEE information security policies and procedures.  
 
 
Data and Analysis: 
A single-subject research design was chosen (in which each subject serves as his or her own 
control) in order to accommodate for the heterogeneity that is well known to characterize 
auditory prosthesis research. Post-operative evaluations will be conducted as described. Blinding 
or masking procedures are not included in the design, as the presence/absence of a brainstem 
implant cannot be easily concealed from the device recipients and/or clinical investigators. 
 
Data will include demographics, vitals, frequency of both major and minor complications as well 
as audiometric and speech and language data. The summary statistics will be reported on the 
various categorical (gender and complications) and continuous (age, audiological and speech 
perception, production and language scores) variables. 
 
Baseline audiologic and speech perception, production and language measures taken prior to 
ABI surgery will be compared to scores at each follow up interval within each subject. For 
subjects with no response on behavioral testing, a maximum threshold of 120 dB HL will be 
assigned at the test frequency as this represents maximum stimulus levels of the equipment. Pure 
tone average (PTA) is calculated using the thresholds from 500, 1,000, and 2,000 Hz. When 

speech perception testing is limited by short duration experience or young age, inattention, or the 
presence of significant comorbidities, these reasons will be recorded. When inability to complete 
the test is evident despite significant implant experience, the patient is assigned the value for 
chance correct responses for the appropriate test (i.e., 0% for open-set tests or 33% for ESP 
pattern-[P] perception tests). When a child advances out of a particular measure because of 
ceiling effects, then the next measure will be undertaken. For children able to perform a given 
speech perception measure(s) prior to ABI surgery, that measure(s) will be repeated at the initial 
post-operative visits to ensure the same test comparisons exist. It will be assumed that children 
that are unable to perform closed set testing will not be able to perform open set testing at a 
given visit. Thus, scores on these tests will be assigned the value of “unable to test.” 
 
Change values for each of the variables will be calculated by subtracting off baseline values 
when available. The mean percent change at the various intervals for each variable can be 
averaged (+/- SD) across the subjects. Comparison to baseline measures for significance testing 
will be made with 95% confidence intervals when possible. The chance that this is not possible 
exists because of the broad variation in ages and possible achievements with the device.  
 
For speech perception, there is a developmental hierarchy that is required to evaluate the 
emergence of this skill over time. This will be tracked and plotted on a graph against similar 
children with normal hearing as well as those fitted with CIs with and without malformations for 
comparison (30, 50). This modified cumulative speech perception index in quiet (SRI-Q) will be 
created after Wang et al. (50) and Buchman et al (30) in an effort to simultaneously display the 
data from all tests in the speech recognition hierarchy as a function of time. ESP-P is considered 
easier than ESP-monosyllabic (M) words. CNC word scores then follow PB-k word scores. The 
measured percentage score for each test (0%–100% correct) is then hierarchically ranked and 
stacked in 100-point increments. These results are controlled for duration of device usage and 
age at implantation. Speech production and language data are reported as age-normed values and 
will be compared to children of a similar age with normal hearing as well as those using CIs. 
 
It is anticipated that this pilot study will be used to demonstrate safety and give some idea 
regarding efficacy. However, a larger scale clinical trial will be needed beyond the pilot study to 
demonstrate surgical safety on a broader scale (across surgeons and institutions) and the utility of 
the device for the intended auditory benefits. Ten pre-lingual subjects and five post-lingual 
should be a sufficient sample size to demonstrate safety. If the European data are correct 
regarding complication rates in children, a single CSF leak might occur in one subject and non-
auditory side effects can be expected to occur in roughly 20% of children or 2-3 subjects in this 
study arm. This number seems to be a conservative and reasonably small number to demonstrate 
these effects. Non-auditory stimulation is not serious and can be programmed around with simple 
changes in device programming during activation. For speech perception and production, the 
within subject design should allow us to see some benefit from the device if effective. Since the 
children are deaf, any development of significant open or closed set perception (beyond patter 
perception) would be attributable to the device. Similarly for language outcomes although these 
will take longer time to develop. Thus, the safety numbers are the drivers in powering this study 
arm. 
 

All data will be entered in to secure records of the Department of Otolaryngology that are 
currently in use. The lead investigator will cross check the data prior to approval for review. The 
data will be exported by desired fields to an Excel spreadsheet (Microsoft) or SAS (Statistical 
Analysis System) for further analysis and if needed, statistical consultation will be sought. 
 
Study Endpoints: 
 
Study endpoints are based on the 3 specific aims. For safety, this will be determined on a case-
by-case basis and any adverse events will be reviewed with the IRB. Should the adverse events 
be deemed unacceptable to the investigators or the IRB, this would be sufficient terms for study 
discontinuation. Five years of follow up was chosen to provide extended time for the emergence 
of open-set speech perception abilities in the pre-lingual cohort of children; however, as little as 
two to three years would be adequate for the assessment of audiologic outcomes: In studies of 
prelinguistic children undergoing CI, at least 2 years of follow-up is needed to demonstrate 
emergence of these skills (23). If no open set perception is demonstrated at 5 years, this seems to 
be good evidence for a lack of benefit on this measure. In general, speech and language measures 
should track speech perception abilities. While the full emergence of these skills can take 
somewhat longer to develop, it is anticipated that early emergence will be evident if speech 
perception is developing. While not anticipated, a clear lack of benefit from the device (such as 
no sound awareness) among multiple subjects would also be consideration for stopping the 
study. Study recruitment is expected to be slow at 1-3/year; however, this will not stop the study. 
 
Remaining Study Considerations: 
The remaining study considerations will be followed as per our original IDE application Clinical 
Trial Protocol, similar to the adult arm of the study that is currently approved. These sections 
have been reproduced and included in this IDE supplement. These include, but are not limited to: 
 Study Design Schematic  
 Device information, compliance, supply, and storage (Section 5 of original Clinical Trial 
Protocol) 
 Study Procedures (Section 7 of original Clinical Trial Protocol) 
 Adverse Event Recording and Reporting (Section 9 of original Clinical Trial Protocol) 
 Statistical Methods/Data Analysis (Section 10 of original Clinical Trial Protocol) 
 Data Handling and Record-Keeping (Section 11 of original Clinical Trial Protocol) 
 Study Discontinuation Criteria (Section 12 of original Clinical Trial Protocol) 
 
 
 
 

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