mellitus causes cochlear microangiopathy and subsequently degeneration of cochlear lateral walls and OHCs. SP311 – Cochlear implantation with cochlear nerve deficiency Joe Walter Kutz, Jr., MD (presenter); Peter Roland, MD; Brandon Isaacson, MD; Kenneth Lee, MD, PhD; Timothy Booth, MD; Melissa Sweeney, MS, CCC/SLP OBJECTIVES: 1) Understand the limitations of cochlear im- plantation in children with a deficient cochlear nerve. 2) Re- alize the importance of adopting new technology for this group of children. METHODS: A retrospective case review was performed to identify children that underwent cochlear implantation with cochlear nerve deficiency. The cochlear nerve was evaluated by high-resolution T2-weighted fast-spin echo MR in the sag- ittal, coronal, and oblique planes. A deficient cochlear nerve was defined as a cochlear nerve that is smaller in diameter when compared with the adjacent nerves in the internal audi- tory canal. The cochlear nerve was considered absent if there was no radiographic evidence of a cochlear nerve. Post-oper- ative performance was measured to determine benefit after cochlear implantation. RESULTS: Six children were identified that underwent co- chlear implantation in an ear without radiographic evidence of a cochlear nerve. The mean age was 6.3 (1-13 years). One child developed pattern perception. The other children failed to demonstrate clear evidence of pattern perception or sound awareness. Two children (ages 1 and 5) underwent cochlear implantation with a deficient cochlear nerve. Both patients developed limited open set speech. CONCLUSIONS: Cochlear nerve absence as determined by MR portends a poor prognosis for cochlear implant perfor- mance. However, children with cochlear nerve deficiency may gain limited open-set speech perception. The potential avail- ability of alternative technology in the United States, such as the auditory brainstem implant, should be strongly considered to provide this group of patients with a viable option for hearing habilitation. SP330 – Cochlear schwannomas Brandon Isaacson, MD (presenter); Peter Roland, MD; Walter Kutz, MD OBJECTIVES: To understand the presentation, imaging char- acteristics and management of cochlear schwannomas. METHODS: Retrospective chart review from 1995 to 2008 was undertaken at a tertiary care academic medical center. Six subjects with isolated intracochlear schwannomas were iden- tified. Treatment included observation with serial imaging and/or excision via a transotic approach. RESULTS: All six patients presented with sensorineural hearing loss. One patient developed vertigo, which was unresponsive to medical management. This patient underwent a transotic removal of her tumor with resolution of her balance disturbance. CONCLUSIONS: Intracochlear schwannomas are rare neo- plasms that present with sensorineural hearing loss. All of the patients in this series presented with or eventually lost all hearing. One subject developed severe imbalance and vertigo, which resolved after transotic removal of her tumor. SP279 – Comparison of caloric test with galvanic test in dizziness Seog Kyun Mun, MD (presenter) OBJECTIVES: The purpose of this study is to characterize various responses by comparing eye movements, which is induced by galvanic vestibular stimulation (GVS), in normal subjects and patients with peripheral vestibulopathy. Another purpose of this study is to estimate the clinical significance of GVS tests in patients with results of caloric test. METHODS: Thirty normal subjects and 17 patients with pe- ripheral vestibulopathy were selected on the basis of medical history and neurological examination. Binaural electric current was applied to each subject’s and patient’s mastoid. And then by carrying out GVS, galvanic stimulating nystagmus (GSN), post-galvanic stimulating nystagmus (PGSN), and spontane- ous nystagmus were evaluated in all of them using a 3D videoelectronystagmography technique. Canal paresis and di- rectional preponderance were measured in patients by alterna- tive binaural bithermal caloric test. RESULTS: In patients with peripheral vestibulopathy, when the negative electrode was attached to the intact side, increased GSN was always directed toward the negative electrode but decreased PGSN was directed toward the negative electrode. When the negative electrode was attached to the lesion side, decreased GSN was directed toward the positive electrode but increased PGSN was directed toward the positive electrode. There was a correlation between canal paresis and response degree of GVS (p0.05). CONCLUSIONS: The response to GVS in patients with pe- ripheral vestibulopathy differed from that in normal subjects, which suggests that GVS could be useful for estimating ves- tibular function. Because response degree of GVS was propor- tionate to canal paresis, it is thought to be another useful method for assessing vestibular functions. SP304 – Conductive/mixed hearing loss: our experience with FIMOS Maurizio Levorato, MD (presenter); Victoria Rivero de Jesus, MD; Luis Garcia-Ibanez, MD; Emilio Garcia-Ibanez, MD OBJECTIVES: 1) To determine the safety of Otologics MET fully implantable ossicular stimulator (FIMOS) implanted with P183 Program Poster Presentations POSTERS