Faculty Bibliography

OBJECTIVE: Magnetic resonance imaging is the gold standard in retrocochlear imaging; however, its role in management of inner ear diseases remains poorly defined. In this study, we investigate the utility of MRI in defining the nature of intracochlear pathology. STUDY DESIGN: A retrospective review of 11 patients with inner ear abnormalities on MRI between 2010 and 2013. Patients' diagnosis included cholesteatoma, labyrinthitis, meningitis, and intralabyrinthine schwannoma. SETTING: Tertiary care hospital. MAIN OUTCOME MEASURES: T1, T2, and postcontrast signal intensities were measured within the lesion and normalized in reference to the contralateral normal cochlea. The following ratios were calculated: T1 postgadolinium lesion/contralateral cochlea, T2 lesion/contralateral cochlea and T1 lesion/contralateral cochlea. Statistical analysis was conducted using the unpaired Student's t test using IBM SPSS Statistics version 20.0.0. RESULTS: The relative intensity ratios were useful in defining the nature of inner ear lesion. Normalized T1 postgadolinium lesion intensities were significantly higher in the tumor group (3.98 +/- 0.880 versus 1.71 +/- 0.370, p < 0.0002). Normalized T1 precontrast signal intensities were higher in tumors (1.33 +/- 0.200 versus 0.842 +/- 0.426, p < 0.0626), and T2 values were lower in tumors (0.838 +/- 0.491 versus 1.10 +/- 0.305, p < 0.317); however, these did not reach significance. CONCLUSION: Intensity of gadolinium enhancement on MRI is useful in differentiation of inflammation from tumors; normalized T1 postgadolinium intensity ratio greater than 3 is strongly suggestive of intralabyrinthine tumor.

A growing number of minimally invasive surgical and diagnostic procedures require the insertion of an optical, mechanical, or electronic device in narrow spaces inside a human body. In such procedures, precise motion control is essential to avoid damage to the patient's tissues and/or the device itself. A typical example is the insertion of a cochlear implant which should ideally be done with minimum physical contact between the moving device and the cochlear canal walls or the basilar membrane. Because optical monitoring is not possible, alternative techniques for sub millimeter-scale distance control can be very useful for such procedures. The first requirement for distance control is distance sensing. We developed a novel approach to distance sensing based on the principles of scanning electrochemical microscopy (SECM). The SECM signal, i.e., the diffusion current to a microelectrode, is very sensitive to the distance between the probe surface and any electrically insulating object present in its proximity. With several amperometric microprobes fabricated on the surface of an insertable device, one can monitor the distances between different parts of the moving implant and the surrounding tissues. Unlike typical SECM experiments, in which a disk-shaped tip approaches a relatively smooth sample, complex geometries of the mobile device and its surroundings make distance sensing challenging. Additional issues include the possibility of electrode surface contamination in biological fluids and the requirement for a biologically compatible redox mediator.

OBJECTIVES/HYPOTHESIS: Melanin is a pigmented polymer with a known role in dermal solar protection. In vertebrates, melanogenesis has been reported in leukocyte populations, suggesting a potential role in innate immunity. In this study, we report the novel finding of melanin associated with chronic inflammation and speculate on its potential role in the middle ear and mastoid. STUDY DESIGN: Retrospective review of case series. METHODS: Medical records of six patients who demonstrated melanin in the ear were reviewed. RESULTS: Six patients from 1 to 63 years of age were identified with extracellular melanin and melanin-laden histiocytes within the middle ear and/or mastoid air cells at time of surgery. Concurrent intraoperative findings included cholesteatoma (n = 3), chronic suppurative otitis media (n = 2), and coalescent mastoiditis (n = 1). Histologically, extracellular melanin and melanin-laden histiocytes were identified by Fontana-Masson stain; absence of melanocytes was confirmed by the absence of Melan-A staining. One patient had a positive stain for CD163 (a marker for macrophages). CONCLUSION: This case series is the first demonstration of melanin within middle ear mucosa without melanocytes in immediate proximity or metastatic melanocytic lesions. Melanin's presence in the setting of inflammation suggests that there may be a heretofore unreported link between the pigmentary and immune systems in the middle ear. LEVEL OF EVIDENCE: 4.

OBJECTIVE: The round window membrane (RWM) is increasingly becoming a target for amplification using active middle ear implants. However, the current strategy of using available transducer tips may have negative consequences for the RWM. We investigated the microanatomy of the RWM to establish a basis for the design of the transducer tip for the RWM driver. STUDY DESIGN: Using the guinea pig as an animal model, microcomputed tomography (muCT) and white light interferometry were used to study the topography of the RWM and RW niche (RWN). The curvatures of the RWM surface were calculated using the topography data. MAIN OUTCOME MEASURES: The 3-dimensional structure of the scala tympani terminal, saddle-shaped surface topography, and surface curvature were determined. RESULTS: The size of the scala terminal was approximated as an ellipse for which the major and minor axes were 1.29 and 0.95 mm. The average minimum and maximum radii of curvature around the center of RWM were -0.44 and +0.70 mm along the minor and major axis. CONCLUSION: The microanatomies of the RWM and RWN have important implications for the design of the transducer tip to maximize energy transfer while minimizing its distortion and permanent disruption. Our results suggest that the size of the transducer tip should be smaller than the minor axis of the scala terminal to avoid collision with the RWN. The driver should be designed to conform to the topography and radius of curvature of the center portion of the RWM, which for a guinea pig is 0.44 mm.

OBJECTIVES/HYPOTHESIS: Childhood obesity, defined as body mass index (BMI) >/= 95%, is a significant health problem associated with a variety of disorders, and in adults it has been found to be a risk factor for hearing loss. We investigated the hypothesis that obese children are at increased risk of sensorineural hearing loss (SNHL). STUDY DESIGN: A complex, multistage, stratified geographic area design for collecting representative data from noninstitutionalized U.S. population. METHODS: Relevant cross-sectional data from the National Health and Nutrition Examination Survey, 2005 to 2006, for 1,488 participants 12 to 19 years of age was examined. Subjects were classified as obese if their BMI >/= 95th percentile. SNHL was defined as average pure-tone level greater than 15 dB for 0.5, 1, and 2 kHz (low frequency) and 3, 4, 6, and 8 kHz (high frequency). RESULTS: Compared to normal weight participants (BMI 5%-85%), obesity in adolescents was associated with elevated pure tone hearing thresholds and greater prevalence of unilateral low-frequency SNHL (15.2 vs. 8.3%, P = 0.01). In multivariate analyses, obesity was associated with a 1.85 fold increase in the odds of unilateral low-frequency SNHL (95% CI: 1.10-3.13) after controlling for multiple hearing-related covariates. CONCLUSIONS: We demonstrate for the first time that obesity in childhood is associated with higher hearing thresholds across all frequencies and an almost 2-fold increase in the odds of unilateral low-frequency hearing loss. These results add to the growing literature on obesity-related health disturbances and also add to the urgency in instituting public health measures to reduce it. LEVEL OF EVIDENCE: 2b. Laryngoscope, 2013.

IMPORTANCE Although smoking and secondhand smoke exposure are associated with sensorineural hearing loss (SNHL) in children and adults, the possible association between prenatal smoke exposure and hearing loss has not been investigated despite the fact that more than 12% of US children experience such prenatal exposure each year. OBJECTIVE To investigate whether exposure to prenatal tobacco smoke is independently associated with SNHL in adolescents. DESIGN Cross-sectional data were examined for 964 adolescents aged 12 to 15 years from the National Health and Nutrition Examination Survey 2005-2006. PARTICIPANTS Participants underwent standardized audiometric testing, and serum cotinine levels and self-reports were used to identify adolescents exposed to secondhand smoke or active smokers. MAIN OUTCOMES AND MEASURES Prenatal exposure was defined as an affirmative parental response to, "Did [Sample Person's Name] biological mother smoke at any time while she was pregnant with [him/her]?" Sensorineural hearing loss was defined as an average pure-tone hearing level more than 15 dB for 0.5, 1, and 2 kHz (low frequency) and 3, 4, 6, and 8 kHz (high frequency). RESULTS Parental responses affirmed prenatal smoke exposure in 16.2% of 964 adolescents. Prenatal smoke exposure was associated with elevated pure-tone hearing thresholds at 2 and 6 kHz (P < .05), a higher rate of unilateral low-frequency SNHL (17.6% vs 7.1%; P < .05) in bivariate analyses, and a 2.6-fold increased odds of having unilateral low-frequency SNHL in multivariate analyses (95% CI, 1.1-6.4) after controlling for multiple hearing-related covariates. CONCLUSIONS AND RELEVANCE Prenatal smoke exposure is independently associated with higher pure-tone hearing thresholds and an almost 3-fold increase in the odds of unilateral low-frequency hearing loss among adolescents. These novel findings suggest that in utero exposure to tobacco smoke may be injurious to the auditory system.

OBJECTIVES/HYPOTHESIS: Surgical repair of large anterior tympanic membrane (TM) perforations continue to be a challenge for the otologic surgeon. Lateral graft tympanoplasty, the recommended treatment, is technically difficult and is plagued with blunting of the anterior sulcus and lateralization of the TM, both of which can lead to conductive hearing loss. In this study, we evaluate the efficacy of "hammock" tympanoplasty in the treatment of anterior perforation. STUDY DESIGN/METHODS: The "hammock" tympanoplasty, a medial graft tympanoplasty, utilizes a large tympanomeatal flap incorporating anterior ear canal skin and the placement of a graft extending from the anterior to the posterior external auditory canal, akin to a hammock. In this retrospective study, the medical, surgical, audiological, and radiological records of 25 patients treated with hammock tympanoplasty were reviewed. RESULTS: The average age of the patients was 40.6 +/- 20 years. The perforation involved the right ear of 17 patients, and at least two quadrants of the TM in 24 of 25 patients. The TM perforation was successfully closed in 24 of 25 patients, with improvement of the air conduction threshold in 22 of 25 patients. None of the patients experienced SNHL or lateralization of TM. There was one patient with blunting of anterior sulcus and another patient who experienced delayed facial paresis 9 days following surgery, which subsequently resolved. CONCLUSION: The hammock tympanoplasty is technically easy, highly effective in restoring the integrity of the TM, and shows improvement in postoperative hearing. LEVEL OF EVIDENCE: 4.

Three elderly patients experienced musical hallucinations (MH) in the context of hearing loss. In at least two of the cases, the onset was sudden. All three patients had pontine T2/FLAIR hyperintense foci on MR scan after the onset of the MH.