Faculty Bibliography

OBJECTIVES: Although there are various available treatment options for unilateral severe-to-profound hearing loss, these options do not provide the benefits of binaural hearing since sound is directed from the poorer ear to the better ear. The purpose of this investigation was to review our center's experience with cochlear implantation in such patients in providing improved auditory benefits and useful binaural hearing. STUDY DESIGN: Retrospective chart review. METHODS: Twelve adult patients and four pediatric patients with unilateral severe-to-profound hearing loss received an implant in the poorer ear. Outcome measures performed preoperatively on each ear and binaurally included consonant-nucleus-consonant (CNC) monosyllabic words and sentences in noise. The mean pure-tune average in the better ear was within normal range. RESULTS: Test scores revealed a significant improvement in CNC and sentence in noise test scores from the preoperative to most recent postoperative evaluation in the isolated implant ear. All adult subjects use the device full-time. CONCLUSIONS: The data reveal significant improvement in speech perception performance in quiet and in noise in patients with single-sided deafness after implantation. Performance might depend on factors including length of hearing loss, age at implantation, and device usage.

OBJECTIVES/HYPOTHESIS: To evaluate the safety and efficacy of acoustic and electric sound processing for individuals with significant residual low-frequency hearing and severe-to-profound high-frequency sensorineural hearing loss. STUDY DESIGN: Prospective, single-arm repeated measures, single-subject design. METHODS: Fifty individuals, >/= 18 years old, with low-frequency hearing and severe high-frequency loss were implanted with the Cochlear Nucleus Hybrid L24 implant at 10 investigational sites. Preoperatively, subjects demonstrated consonant-nucleus-consonant word scores of 10% through 60% in the ear to be implanted. Subjects were assessed prospectively, preoperatively, and postoperatively on coprimary endpoints of consonant-nucleus-consonant words, AzBio sentences in noise, and self-assessment measures. RESULTS: Significant mean improvements were observed for coprimary endpoints: consonant-nucleus-consonant words (35.8 percentage points) and AzBio sentences in noise (32.0 percentage points), both at P < 0.001. Ninety-six percent of subjects performed equal or better on speech in quiet and 90% in noise. Eighty-two percent of subjects showed improved performance on speech in quiet and 74% in noise. Self-assessments were positive, corroborating speech perception results. CONCLUSION: The Nucleus Hybrid System provides significant improvements in speech intelligibility in quiet and noise for individuals with severe high-frequency loss and some low-frequency hearing. This device expands indications to hearing-impaired individuals who perform poorly with amplification due to bilateral high-frequency hearing loss and who previously were not implant candidates. LEVEL OF EVIDENCE: 2b. Laryngoscope, 2015.

Hearing impairment is a significant disability. According to the World Health Organization (WHO), more than 80% of the world's approximately 120 million people with hearing impairment live in developing countries. Cochlear implant is the only therapeutic intervention for those with severe-profound sensorineural hearing loss. We are reporting an interesting case of the very first cochlear implant operation carried out in Uganda. The patient was a 23 year old male whose presenting complaint was inability to hear in the left ear for three and a half years and in the right ear for one year. He had been treated for TB(Tuberculosis) mastoiditis. After the 8 months of treatment, the otorrhea persisted and he underwent a tympanomastoidectomy on the same ear. He reported no familial history of hearing loss. On examination, ENT examination revealed a small pars flaccida retration pocket of the right tympanic membrane with cholesteatoma. The left ear had an intact tympanic membrane. Pure tone audiometry revealed profound sensorineural hearing loss in both ears (see attached PTA results), CT scan of the temporal bone showed normal inner ear anatomy bilaterally and mild sclerotic changes in both mastoid bones. He then had surgery on his right ear which included cochlear implantation. The cochlear implant (CI) was activated on the first postoperative day remotely via internet with the help of the cochlear implant team at New York University Cochlear Implant Center and the patient was immediately able to appreciate some sounds. He received a pneumococcal vaccine on the first postoperative day and was discharged the following day.

OBJECTIVE: To validate a method of measuring angular depth of insertion (aDOI) as well as positional depth of each electrode contact in a cochlear implant by using intraoperative postinsertion skull radiographs. STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: Intraoperative postinsertion radiographs obtained from 18 cochlear implant recipients were chosen for analysis. One high-resolution computer tomography scan of the head with the electrode in place was also analyzed. One cadaveric temporal bone with an inserted electrode provided additional data for analysis. INTERVENTION: aDOI and position of each electrode contact were measured from the radiographs using readily available software. High-resolution computer tomography imaging of the cochlea and electrode were reconstructed in three dimensions and used to simulate head rotation during intraoperative radiographs. The cadaveric temporal bone was imaged by x-ray at various acquisition angles. MAIN OUTCOME MEASURES: We evaluated the error introduced in measuring aDOI by assessing intra- and inter-rater variability. We also evaluated the error introduced by x-ray acquisition at nonstandardized angles by analyzing the three-dimensional construct and the cadaveric temporal bone. RESULTS: The concordance correlation coefficients for intrarater (0.991) and inter-rater (0.996) variability in aDOI measurement were excellent. The error introduced by nonstandardized x-ray acquisition angles was only -12.5 degrees to +15.8 degrees even at the limits of clinically relevant head rotation. CONCLUSIONS: The intraoperative postinsertion radiograph is sufficient for estimating positional depth of electrode contacts and the aDOI. This measure is robust in the face of nonstandardized x-ray acquisition angles, and shows good intra- and inter-rater variability.

OBJECTIVES: Commercially available cochlear implant systems attempt to deliver frequency information going down to a few hundred Hertz, but the electrode arrays are not designed to reach the most apical regions of the cochlea, which correspond to these low frequencies. This may cause a mismatch between the frequencies presented by a cochlear implant electrode array and the frequencies represented at the corresponding location in a normal-hearing cochlea. In the following study, the mismatch between the frequency presented at a given cochlear angle and the frequency expected by an acoustic hearing ear at the corresponding angle is examined for the cochlear implant systems that are most commonly used in the United States. DESIGN: The angular insertion of each of the electrodes on four different electrode arrays (MED-EL Standard, MED-EL Flex28, Advanced Bionics HiFocus 1J, and Cochlear Contour Advance) was estimated from X-ray. For the angular location of each electrode on each electrode array, the predicted spiral ganglion frequency was estimated. The predicted spiral ganglion frequency was compared with the center frequency provided by the corresponding electrode using the manufacturer's default frequency-to-electrode allocation. RESULTS: Differences across devices were observed for the place of stimulation for frequencies below 650 Hz. Longer electrode arrays (i.e., the MED-EL Standard and Flex28) demonstrated smaller deviations from the spiral ganglion map than the other electrode arrays. For insertion angles up to approximately 270 degrees , the frequencies presented at a given location were typically approximately an octave below what would be expected by a spiral ganglion frequency map, while the deviations were larger for angles deeper than 270 degrees . For frequencies above 650 Hz, the frequency to angle relationship was consistent across all four electrode models. CONCLUSIONS: A mismatch was observed between the predicted frequency and the default frequency provided by every electrode on all electrode arrays. The mismatch can be reduced by changing the default frequency allocations, inserting electrodes deeper into the cochlea, or allowing cochlear implant users to adapt to the mismatch. Further studies are required to fully assess the clinical significance of the frequency mismatch.

OBJECTIVES: X-linked deafness is a potential etiology of sensorineural hearing loss characterized by bulbous dilatation of the fundus of the internal auditory canal (IAC) and the absence of the bony plates separating the basal turn of the cochlea and IAC. These malformations predispose patients to IAC insertion during cochlear implantation (CI). Our objective is to describe the surgical technique, audiometric and speech performance outcomes in a group of patients with this unique cochlear malformation. METHODS: A retrospective chart review was performed of all patients at a tertiary care facility who underwent CI between January 2006 and July 2011. RESULTS: A total of five patients were identified with radiographic findings characteristic of X-linked deafness, specifically a deficient modiolous, absent lamina cribrosa and bulbous IAC. A modified cochleostomy was utilized to ensure electrode insertion within the scala tympani avoiding the IAC. In each case, fluoroscopy was utilized to visual electrode progression during insertion and complete insertion was accomplished. All patients demonstrated improved speech performance following implantation. CONCLUSIONS: Utilizing the techniques described, patients with these unique radiographic findings consistent with X-linked deafness may successfully undergo CI with excellent potential for auditory rehabilitation.

Motion sickness can be a limiting factor for sea and air missions. We report the experience of a Pararescue (PJ) team on a Pacific Ocean rescue mission in which motion sickness was prevalent. Cinnarizine, an antagonist of H1-histamine receptors, was used to treat affected PJs. We also report findings of a survey of PJs regarding motion sickness. A family of four on a disabled sailboat 900 miles off the coast of Mexico sent out a distress call because their 1-year-old daughter became severely ill with fever and diarrhea. Four PJs were deployed on a C-130, performed a free-fall parachute insertion into the ocean, and boarded the sailboat. All four PJs experienced onset of motion sickness at some point during the early part of the mission and symptoms persisted through the first 24 hours. Three PJs experienced ongoing nausea, vomiting, dizziness, and sensory imbalances. The captain of the sailboat offered the three sick PJs approximately 18mg of cinnarizine two or three times a day with relief of symptoms and improvement on operational effectiveness. A new, anonymous, voluntary survey of Air National Guard PJs and combat rescue officers revealed that 78.4% of Operators have experienced motion sickness at sea. We discuss the current theories on motion sickness, the effect of motion sickness on operational effectiveness, and research on treatment of motion sickness, including the medication cinnarizine.

Although the preponderance of cerebellopontine angle lesions are schwannomas, focused attention to patient clinical history, imaging studies, and tissue biopsies when indicated will aid in detection of less common lesions that might otherwise be misdiagnosed. This is most critical for pathologies that dictate different management paradigms be undertaken.