Faculty Bibliography

Objective Preservation of residual low-frequency hearing has become a priority in cochlear implantation. The purpose of this study was to compare rates of hearing preservation and effects on performance of loss of low-frequency acoustic hearing with two different length electrodes. Study design Retrospective chart review. Setting Tertiary Care Hospital. Patients Twelve patients were implanted with the CI422 a slim-straight electrode; the second group consisted of 10 patients implanted with the Hybrid-L, a shorter hearing preservation electrode. Main outcome measure Audiometric thresholds and speech perception measures. Results At 1 year, 3/10 (30%) patients with the Hybrid-L and 7/12 (58%) patients with the CI422 lost residual acoustic hearing resulting in a profound hearing loss in the implanted ear. In comparing these patients in particular, mean CNC words in the implanted ear were 72% in the CI422 electrode group and 15% in the Hybrid-L electrode group at 1 year (P = 0.03). While hearing preservation rates with the Hybrid-L tended to be better, among recipients who lost residual hearing, speech perception was better in those with the longer CI422 electrode. Conclusions With emphasis on preservation of residual hearing, patients need to be counseled regarding possible outcomes and options should loss of residual hearing occur following implantation. While shorter electrodes may have better rates of hearing preservation, the patients with the longer straight electrode in our study had significantly better speech understanding following the loss of residual hearing.

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: To examine the variables affecting outcomes for sequential bilateral cochlear implantation patients in the adolescent population. STUDY DESIGN: Retrospective chart review at tertiary care center. METHODS: Main outcome measures were open set speech recognition tests at the word (Consonant-Nucleus-Consonant/Phonetically Balanced Kindergarten List Test [CNC/PBK]) and sentence levels in noise (Hearing in Noise Test-Noise [HINT-N]) in different test conditions with respect to the age at first and sequential implantation, as well as the interval between implants. RESULTS: Despite a mean age at sequential implantation of 13.5 years, sequential bilateral implanted adolescents revealed significant improvement in the sequential cochlear implant (CI2) ear. The mean time interval between implants was 8.2 years. A wide range of performance was noted, and age at implantation and interval between first cochlear implant (CI1) and CI2 did not predict outcome. Mean CNC/PBK score with CI1 alone was 83.0%, with the CI2 alone was 56.5%, and with bilateral implants was 86.8%. Sentence scores (HINT-N) were 89.5% for CI1, 74.2% for CI2, and 94.4% for bilateral CI condition. The clinical relevance of these enhanced perception abilities requires attention to individual device use, performance with the first implant, and subjective benefits reported by patients. CONCLUSIONS: Bilateral sequential cochlear implantation leads to improved speech perception in the adolescent population and should be considered in this population, even after a long period of deafness and despite a prolonged interval between implants. Numerous factors affect the ability to predict performance, but age at implantation and interimplant interval were not correlated with performance measures. Extensive preoperative counseling and individualized evaluation are critical to ensure that patients and families understand the range of possible outcomes. LEVEL OF EVIDENCE: 6. Laryngoscope, 2015.

OBJECTIVE: To assess whether recombinant growth factor (hGH) therapy has an effect on cochlear implant (CI) performance. PATIENTS: Two pediatric CI recipients (S1, S2) who underwent treatment with hGH for short stature were identified for review. S1 has bilateral labyrinthine dysplasia and received implants at ages 10 months (right) and 4 years 3 months (left). S2 was diagnosed with severe to progressive sensorineural hearing loss bilaterally and received a CI at age 9 years 10 months (left). INTERVENTION(S): Case series. MAIN OUTCOME MEASURE(S): Cochlear implant, hGH, and speech perception data were collected. Phonetically Balanced Kindergarten (PBK) and Consonant Nucleus Consonant (CNC) word recognition scores were reviewed to assess auditory perception. Electrode impedances, threshold levels, and comfort levels were also reviewed. RESULTS: After 4 months of hGH, word recognition scores for S1 were observed to decrease from 90 to 72% (right) and were stable at 40% (left). Despite troubleshooting, performance continued to decline bilaterally to 52% (right) and 28% (left), and the decision was made to discontinue hGH. One month after cessation of hGH, word recognition scores began improving to 74% (right) and 68% (left). Word recognition scores for S2 were observed to have decreased from 92% the previous year to 82% after taking hGH for 2 months. Given both our previous experience with S1 and discussions with S2's parents, hGH was discontinued after 10 months of therapy. Two months after cessation of hGH, S2's word recognition had improved to 86% (left). CONCLUSIONS: Our case studies illustrate that implanted children undergoing treatment with hGH may experience a decrease in speech perception, which recovers after the cessation of treatment. Since hGH use has become more prevalent in recent years, it is important to inquire whether children undergoing, or who have undergone, implantation are receiving hGH so that they may be appropriately monitored.

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.

OBJECTIVES/HYPOTHESIS: Trauma to intracochlear structures during cochlear implant insertion is associated with poorer hearing outcomes. One way surgeons can influence insertion trauma is by choosing the surgical approach. We seek to compare cochleostomy (CO), peri-round window (PRW), and round window (RW) approaches using a fresh frozen temporal bone model. STUDY DESIGN: Experiments using fresh frozen temporal bones. METHODS: Cochlear implant insertions using the three aforementioned approaches were performed on 15 fresh frozen human temporal bones using a Cochlear 422 electrode. Insertions were evaluated by examining fluoroscopic recordings of histologic sections. RESULTS: Five cochlear implant insertions were performed using each of the three aforementioned approaches. Fluoroscopic examination revealed that none of the CO or PRW insertions contacted the modiolus during insertion, whereas three of five RW insertions did. RW insertions were less linear during insertion when compared to CO and PRW insertions (P < .05). CO insertions had significantly larger angular depth of insertion (487 degrees ) when compared to PRW (413 degrees ) and RW (375 degrees ) (P < .05). Histologic examination revealed one RW insertion resulted in osseous spiral lamina fracture, whereas the remaining insertions had no evidence of trauma. In the damaged specimen, the inserted electrode was observed to rest in the scala vestibuli, whereas the remaining electrodes rested in the scala tympani. CONCLUSIONS: Due to variability in RW anatomy, a CO or PRW window surgical approach appears to minimize the risk for insertion trauma. However, with favorable anatomy, a Cochlear 422 electrode can be inserted with any of the three approaches. LEVEL OF EVIDENCE: NA Laryngoscope, 125:966-971, 2015.

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.