Arunkumar N. Badi

Development of a Novel Eighth-Nerve Intraneural Auditory Neuroprosthesis†

Objectives/Hypothesis Cochlear nerve stimulation using a linear array of electrodes, the cochlear implant, has become an accepted treatment for profound deafness. Major limitations of this technology are high threshold of stimulation, poor performance in a noisy background, cross‐talk between electrodes, unsatisfactory channel selectivity, and variable reconstruction of frequency space. A novel auditory neuroprosthesis is proposed that is expected to overcome these problems by implanting an array of three‐dimensional microelectrodes, the Utah Electrode Array, directly into the cochlear nerve.

Defining common outcome metrics used in obstructive sleep apnea

Sleep-disordered breathing a spectrum that ranges from snoring through disorder of increased airway resistance, to overt sleep apnea affects many clinical disease outcomes. Traditionally, disease outcomes have been measured by polysomnography, with the most common metric being the apnea hypopnea index (AHI). Multiple other clinical metrics are commonly used to assess the severity and impact of disease on important outcomes of obstructive sleep apnea (OSA). These allow assessment of sleepiness, quality of life, performance, and medical, especially cardiovascular outcomes. Currently the available metrics only partially explain the associated disease outcomes in different patients. This review highlights the available clinical, physiological and biomarker metrics in measuring OSA and associated co-morbidities and defines treatment goals.

Electrode independence in intraneural cochlear nerve stimulation.

Objectives/Hypothesis: We have previously reported feline electrophysiological and anatomical studies focused on the development of an intraneural auditory neuroprosthesis. Because only the tips of the electrodes implanted in the cochlear nerve are the stimulating elements that abut the nerve axons, we hypothesize that intraneural stimulation will be highly focal in nature. In this article, we report the electrophysiological characterization of the selective activation of subpopulations of cochlear nerve fibers via electrodes implanted in feline cochlear nerve. Study Design: We have used a forward-masking paradigm to estimate the extent of stimulation overlap produced by pairs of electrodes implanted into the cochlear nerve. Methods: The technique uses sequential stimulation via masking and probe electrodes and monitoring of the electrically evoked auditory brain stem response as an index of cochlear nerve fiber recruitment. We investigated overlap in all possible electrode pair combinations. Results and Conclusion: Many electrode pairs manifest virtually no overlap in the subpopulations of fibers excited by perithreshold stimuli, whereas most had considerable overlap at higher stimulation levels. However, we also noted that our measured overlap was similar across electrodes possibly because of lack of specificity of the whole nerve electrically evoked auditory brain stem response as an assay for this parameter. These findings indicate that direct cochlear nerve stimulation via intraneural electrodes provides selective excitation of small subpopulations of cochlear nerve fibers, and suggest that cochlear nerve stimulation may selectively evoke narrow-band frequency percepts.

Selective Activation of Cat Primary Auditory Cortex by way of Direct Intraneural Auditory Nerve Stimulation

Objectives/Hypothesis: Although cochlear implants have been successfully used by many individuals with profound hearing impairment, limitations still remain with this approach to hearing restoration, including poor stimulation selectivity because of cross‐talk between electrodes and poor low‐frequency percepts. These limitations may be mitigated by direct intraneural stimulation of the auditory nerve by way of an array of penetrating microelectrodes. Such an approach should provide focal stimulation and selective activation of the nerve fibers, thereby minimizing cross‐talk among implanted stimulating electrodes and evoking narrow‐band frequency percepts.

P195: A Novel Mucosal Sparing Partial Glossectomy for OSA

trophy permits direct therapy during each treatment session to areas contributing most to hypopharyngeal obstruction. METHODS: The degree to which the tongue obstructs the airway is assessed preoperatively. A Gyrus two-prong probe (85 watts, rapid pulse, 600 joules) is inserted in each hemitongue three times (3600 joules). The heat energy is radially dispersed from the probe tip through the surrounding tongue musculature. In patients having predominant lateral hypertrophy the probe is inserted at six sites in the configuration of a laterally based equilateral triangle (bowtie). In patients with central hypertrophy, the probe is introduced at four paramedian and two lateral sites, creating two medially based equilateral triangles (diamond). Nonspecific hypertrophy warrants three staggered, wavy parallel probe insertions in the longitudinal direction on each side (zig-zag). RESULTS: Application of TC-RF allows for site-specific tongue reduction. Interval home or hospital-based sleep studies determine the effectiveness of the procedure with respect to snoring, the apnea-hypopnea index, oxygen desaturation, and sleep disturbance. Configuring simple geometric shapes to target tongue contour irregularities, clinically significant muscle ablation can be achieved. CONCLUSIONS: Assessment of tongue mass and topography permits use of TC-RF to precisely ablate tongue muscle, requiring fewer treatment sessions, and achieving effective results following each intervention.

R163: MRI of the Airway with Controlled Ventilation in OSA

cellular H2O2 Assay and Immunoblotting were perfomed to measure the oxidative stress and secreted proteins, respectively. RESULTS: H2O2 induced only MUC5AC production and secretion via transcriptional regulation and the MAP kinase signal pathway, through ERK MAP kinase in particular. In addition, ECG markedly inhibited H2O2-induced MUC5AC gene expression and secretion. ECG also suppressed the phosphorylation of ERK MAP kinase. CONCLUSION: These results show that ECG inhibits the H2O2-induced MUC5AC gene and MUC5AC protein expression in human airway epithelium through suppressing the ERK MAP kinase. SIGNIFICANCE: Therefore, it is proposed that a nasal topical application would be more useful than oral uptake to reach the effective experimental dosage in using ECG as a therapeutic agent against the nasal mucus hypersecretory diseases.

Pediatric fungal sinusitis in immunocompromised patients: Case controlled study

Abstract Objectives: To determine parameters that predispose toward invasive fungal sinusitis (FS)in immunocompromised patients Methods: We conducted a retrospective chart review of 10 patients with lymphoproliferative disorders who developed invasive FS and compared them to 20 subjects with lymphoproliferative disorders who did not develop invasive FS. Signs and symptoms, endoscopic findings, radiographic findings, anatomic location of the lesions, absolute neurophil counts, medication preceding presentation, treatment, and outcome of the 2 groups were compared. Results: Fever and facial pain are the most common complaints in both patient groups. All patients had evidence of neutropenia and absent absolute neutrophil counts (ANC). Endoscopy in those patients with FS demonstrated mucosal edema, crusting, or white exudate. A general anesthetic was required for every endoscopy. Radiographic abnormalities were found in both groups and did not aid in FS diagnosis. Conclusions: Immunocompromised patients who present with fever or facial pain and neutropenia need to be evaluated promptly for possible FS. Endoscopic abnormalities were found to be the most reliable indicator of FS in this group of patients. In pediatric patients, a general anesthetic should be considered to enhance optimal endoscopic examination and facilitate nasal biopsies.