Hemangioma of the vertical segment of the facial nerve.
Explore the source record for details and available documents.
Cranial Nerve Neoplasms↗
Biomedical subjects
Marc D Eisen
Publications and source records attributed to Marc D Eisen.
Cerebrospinal fluid cytology to aid the diagnosis of cerebellopontine angle tumors.
OBJECTIVE: To determine if cerebrospinal fluid (CSF) cytology can be useful in the workup of patients with internal auditory canal/cerebellopontine angle (IAC/CPA) tumors and facial paralysis to diagnose metastatic disease before surgical intervention. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: Patients who presented with or developed facial paralysis and IAC/CPA tumors. OUTCOME MEASURE: Lumbar puncture and CSF cytological analysis. RESULTS: Seven patients presented with or developed high-grade facial paralysis (greater than House-Brackmann Grade II). In the first patient, excision of the tumor revealed adenocarcinoma. All subsequent patients were evaluated with CSF cytological analysis. In five of these patients, cytological CSF analysis revealed malignant cells, suggesting a diagnosis of a metastatic lesion rather than acoustic neuroma. Primary neoplasms were identified in all but one of these patients. A sixth patient had metastatic breast cancer, but negative CSF cytology and a stable CPA tumor after radiation treatment. Two patients who were being conservatively followed up for their IAC/CPA tumor developed a nonprogressive but persistent mild Grade II facial weakness and underwent CSF analysis which tested negative. One patient had surgical resection with pathologic findings consistent with a typical acoustic schwannoma, and the other patient has been conservatively followed up without change. CONCLUSION: Our experience suggests that patients presenting with IAC/CPA tumors and progressive facial paralysis of House-Brackmann Grade III or greater should have a CSF cytological examination before surgical intervention to evaluate for a malignant process.
Adenocarcinoma↗
Electrode interaction in pediatric cochlear implant subjects.
Multielectrode cochlear implants rely on differential stimulation of the cochlear nerve for presenting the brain with the spectral and timing information required to understand speech. In implant patients, the degree of overlap among cochlear nerve fibers stimulated by the different electrodes constitutes the electrode interaction. Electrode interaction degrades the spectral resolution of the implant's stimulus. We sought to define electrode interaction in a cohort of pediatric cochlear implant subjects as a function of both stimulus intensity and electrode location along the array. The 27 pediatric subjects that completed the study were implanted with either the Clarion Hi-Focus array with or without positioner, the Nucleus 24 Contour array, or the Nucleus 24 Straight array. All but two of the patients had congenital hearing loss, and none of the patients had meningitis prior to the onset of deafness. The cochlear nerve response was measured with the electrically evoked compound action potential (ECAP). A forward masking protocol was used such that a probe stimulus electrode remained fixed while a preceding masker was moved across the array. Electrode interaction was estimated by measuring the unmasked probe response minus the masked probe response. Three probe locations and three probe intensities were examined for each subject. At all probe locations, electrode interaction increased as probe intensity increased (p < 0.05). Interaction at the basal probe was less than that at either the middle or apical probe locations (p < 0.05), and significant correlation found between probe distance from the basal end of the array and electrode interaction (p < 0.001). These results demonstrate that in this cohort of pediatric subjects, electrode interaction depended on both stimulus intensity and probe location. Implications of these findings on future implant array design and current implant fitting strategies are discussed. The impact of electrode interaction on implant performance is yet to be elucidated.
Artifacts↗
Large releasable pool of synaptic vesicles in chick cochlear hair cells.
Hearing requires the hair cell synapse to maintain notable temporal fidelity (< or =1 ms) while sustaining neurotransmitter release for prolonged periods of time (minutes). Here we probed the properties and possible anatomical substrate of prolonged neurotransmitter release by using electrical measures of cell surface area as a proxy for neurotransmitter release to study hair cell exocytosis evoked by repetitive stimuli. We observed marked depression of exocytosis by chick tall hair cells. This exocytic depression cannot be explained by calcium current inactivation, presynaptic autoinhibition by metabotropic glutamate receptors, or postsynaptic receptor desensitization. Rather, cochlear hair cell exocytic depression resulted from the exhaustion of a functional vesicle pool. This releasable vesicle pool is large, totaling approximately 8,000 vesicles, and is nearly 10 times greater than the number of vesicles tethered to synaptic ribbons. Such a large functional pool suggests the recruitment of cytoplasmic vesicles to sustain exocytosis, important for maintaining prolonged, high rates of neural activity needed to encode sound.
Animals↗
Electrically evoked compound action potential amplitude growth functions and HiResolution programming levels in pediatric CII implant subjects.
OBJECTIVE: To characterize the amplitude growth functions of the electrically evoked compound action potential (ECAP) in pediatric subjects implanted with the Clarion HiFocus electrode array with respect to electrode position and the presence or absence of a Silastic positioner. Electrophysiologic growth function data are compared with HiResolution (HiRes) psychophysical programming levels. DESIGN: ECAP growth functions were measured for all electrodes along the implant's array in 16 pediatric subjects. Nine of the patients were implanted with a Silastic positioner, whereas seven had no positioner. ECAP thresholds and growth function slopes were calculated. Fifteen of the 16 patients had psychophysical threshold and maximum comfort levels available. Programming levels and ECAP thresholds were compared within and among the subjects. RESULTS: ECAP thresholds showed variability among patients, ranging from 178 to 920 nA at 32 musec pulse width. ECAP thresholds did not depend on electrode position along the cochlea but were lower in the presence of the Silastic positioner (p < 0.001). Thresholds determined with the masker-probe versus the alternating polarity paradigms revealed moderate (r = 0.76) correlation. Growth function slopes also showed considerable variation among patients. Unlike thresholds, slopes decreased from apical to basal cochlear locations (p < 0.001) but showed no difference between the absence and presence of the positioner. Programming levels in HiRes were correlated with ECAP threshold levels. When ECAP thresholds were adjusted for each patient by the difference between M level and ECAP threshold at electrode 9, however, overall correlation between the two measurements was excellent (r = 0.98, N = 224). CONCLUSIONS: In pediatric subjects with the Clarion HiFocus electrode, ECAP growth function thresholds appear to decrease with the presence of the Silastic positioner but are unaffected by electrode position along the array. Growth function slope, however, depends on electrode position along the array but not on the presence of the positioner. ECAP programming levels can reliably predict stimulus intensities within the patients' dynamic ranges, but considerable variability is seen between ECAP thresholds and HiRes programming levels.
Acoustic Impedance Tests↗
Djourno, Eyries, and the first implanted electrical neural stimulator to restore hearing.
Explore the source record for details and available documents.
Algeria↗
Otolaryngologic aspects of the Lewis & Clark Expedition, 1803-1806.
Medical difficulties related to otolaryngology that occurred during the Lewis & Clark Expedition (1803-1806) are highlighted. These difficulties included ear and face frostbite, upper respiratory infections, temporal vessel laceration from an air gun accident, neck scrofula, and a pediatric neck mass. The custom of Clatsop Indian head flattening is also described. These descriptions also aim to illustrate the state of otolaryngology during the early 19th century in America.
Child↗
Inverted papilloma of the sphenoid sinus presenting with auditory symptoms: a report of two cases.
OBJECTIVES: The report aims to inform the reader of cases of inverted papilloma involving the sphenoid sinus presenting with auditory symptoms. STUDY DESIGN: Case series. METHODS: A retrospective medical record analysis was carried out to identify patients with inverted papilloma involving the sphenoid sinus that presented with a primary complaint of hearing loss or tinnitus, or both. Clinical records, including initial history and physical examination, audiologic and radiologic studies, and operative and histopathologic reports, were carefully examined. A complete literature review for relevant studies was performed to explore possible pathophysiologic factors and similar cases. RESULTS: Two patients with inverted papilloma presenting with primary auditory complaints were identified. One patient had roaring tinnitus and sensorineural hearing loss demonstrated with audiologic assessment, whereas the other had pulsatile tinnitus. Both patients had biopsy-proven inverted papilloma involving the sphenoid sinus, and both patients underwent endoscopic resection of the disease. No other cause or origin of their auditory symptoms was confirmed. The auditory symptoms of both patients improved markedly after excision of their inverted papillomas. CONCLUSIONS: Tinnitus with or without hearing loss is an unusual presentation of inverted papilloma of the sphenoid sinus. Sphenoid tumors should be considered in the workup of these symptoms.
Adult↗