Ipsilateral Hearing Research Articles

Atraumatic round window deep insertion of cochlear electrodes

Conclusion: This study shows that by using the round window approach and deep insertion, it is possible to reduce electrode insertion trauma (EIT), as indicated by the results of the hearing preservation marker. Objectives: In this prospective study EIT was evaluated in 42 subjects with low frequency hearing before surgery with 28 mm round window deep insertion. Methods: The degree of hearing preservation was a marker of EIT. Pure tone audiometry, monosyllable testing was conducted preoperatively and then at 3, 6, and 13 months after surgery. Results: Immediate hearing preservation (3 months postoperatively) was 92.9% (39/42). The surgery-related hearing preservation 13 months after surgery varied from 85% (34/40) to 90% (36/40). The ipsilateral implanted ear showed significant differences between preoperative and postoperative hearing thresholds (p < 0.005). Comparisons of thresholds for the control ear showed a significant difference between preoperative and postoperative thresholds tested 13 months after surgery (p < 0.05). When the subtraction factor of the mean contralateral hearing loss for each tested frequency for the same time interval was applied to the implanted ear, no significant hearing loss was found, showing that postoperative ipsilateral progressive hearing loss was caused by etiology rather than surgery.

Efficacité de la radiothérapie en première intention d’un paragangliome carotidien non résécable

Carotid paragangliomas are rare. Surgical resection is the primary treatment. However, when surgery is impossible, radiation therapy is an alternative potentially enabling local control with less morbidity. We report a case of good local control of an unresectable paraganglioma after external beam radiation. A 72-year-old-woman, had a 4-year history of right facial palsy associated with pulsatile tinnitus, episodic ear bleeding and ipsilateral hearing loss. Physical examination revealed a retro-mandibular and sub-mastoid pulsatile mass. Magnetic resonance imaging showed a large carotid paraganglioma involving the temporal bone. Since surgical resection was impossible, our patient was given external beam radiation therapy at a dose of 60 Gy. At 12 months follow-up, local control was good without significant toxicity. External beam radiation therapy seems to be a good alternative therapy for local control of carotid paragangliomas if surgical resection is impossible.

“Sixteen and a half”: a novel pontine neuro-ophthalmological syndrome

Two neuro-ophthalmological syndromes due to paramedian pontine infarction have previously been described. The ‘‘one and a half’’ syndrome was first reported and named by Miller Fisher [1], and consists of horizontal gaze palsy combined with an ipsilateral inter-nuclear ophthalmoplegia (INO) resulting in loss of all horizontal eye movements except abduction of the contralateral eye. The causative lesion is usually within the ipsilateral pontine tegmentum and is due to involvement of the abducens nucleus plus the medial longitudinal fasciculus (MLF), or alternatively to involvement of the MLF plus the paramedian pontine reticular formation (PPRF). These structures lie in close proximity to the nucleus and intra-axial fasiculus of the facial nerve. Consequently, ipsilateral fascicular lower motor neurone facial nerve palsy may accompany the ‘‘one-and-a-half’’ syndrome. This situation was named the ‘‘eight and a half syndrome’’ by Eggenberger [2], who reported 3 cases of this syndrome that had occured secondary to ischaemic stroke. In continuation of this concept, we here describe the ‘‘sixteen and a half syndrome’’, which is the ‘‘one and a half’’ syndrome with an additional 7th and 8th cranial nerve (vestibulo-cochlear nerve) palsy. A 78-year-old right-handed man presented with sudden onset of incomplete right upper limb paresis, horizontal diplopia and ataxia. This was shortly followed by complete right lower limb paresis. There was associated nausea and vomiting. Examination revealed a left-sided lower motor neurone facial nerve palsy and dysarthria with loss of conjugate gaze to the left and loss of adduction of the left eye. Abduction of the right eye was accompanied by horizontal nystagmus. Convergence was spared. The patient also complained of new-onset left-sided hearing loss. The patient and his family were certain that his hearing before this event had been normal. Magnetic resonance imaging (MRI) with diffusion-weighted sequences revealed an area of restricted diffusion consistent with an acute infarct. The lesion extended beyond and lateral to the paramedian pontine territory supplied by the anteromedial group of pontine perforating arteries, and dorsally to the fourth ventricle and the region of the facial colliculus (Fig. 1a, b). Pure tone audiometry showed no detectable hearing in the left ear. Brainstem auditory evoked potential testing showed no reproducible wave I, wave III or wave V after left ear stimulation. Waves I, III and V from right ear stimulation were of low amplitude with normal absolute and interwave latencies. Eight months later, the Weber test lateralized to the right ear, and the Rinne test revealed absent air-conducted and bone-conducted sound perception in the left ear. Our patient had an ‘‘eight and a half’’ syndrome plus additional ipsilateral hearing loss. We name this clinical entity the ‘sixteen and a half syndrome’. Hearing loss has not previously been described in association with either ‘‘one and a half’’ or ‘‘eight and a half’’ syndrome. A clinical series of 20 cases of ‘‘one and a half’’ syndrome noted G. Cummins R. Dunne K. O’Rourke (&) T. Lynch Dublin Neurological Institute, Mater Misericordiae University Hospital, 57 Eccles St., Dublin 7, Ireland e-mail: killian.orourke@gmail.com

Is Electric Acoustic Stimulation Better Than Conventional Cochlear Implantation for Speech Perception in Quiet?

To assess whether combined electric acoustic stimulation (EAS) provides a significant hearing-in-quiet advantage over ipsilateral electrical stimulation alone, ipsilateral acoustic stimulation alone, or full-length cochlear implantation without preserved hearing. Tertiary care academic referral center. Two matched groups of cochlear implant (CI) patients that were implanted with either an EAS or full-length device and use similar speech processing strategies. EAS cochlear implantation and hearing preservation (n = 10, EAS group) or conventional CI (n = 10, conventional CI group) without hearing preservation. Status of residual hearing and speech perception data in quiet at 3 and 6 months after fitting. Preoperatively, the mean aided Consonant Nucleus Consonant Word Test word score was 24.2 +/- 8.3% for the EAS group and 20.7 +/- 11.36% for the conventional CI group (p = 0.14). In the conventional CI group, hearing was not preserved after surgery in any subject, whereas 9 of the 10 subjects in the EAS group had hearing preservation. Mean CNC word scores at 6 months after activation using electrical stimulation alone were 50.3 +/- 11.53% in the EAS group and 53.8 +/- 17.32% in the conventional CI group (p = 0.81). Between-condition comparisons among the EAS subjects revealed that combined stimulation was significantly better than either the electrical or acoustic stimulation condition alone (p < 0.05). When compared with the conventional CI group, combined stimulation in EAS subjects was again superior (p < 0.05). Limited length CI with ipsilateral hearing preservation provides comparable speech perception performance results to conventional CI when electric stimulation alone is used. The addition of ipsilateral acoustic stimulation in ears with preserved residual hearing provides an additional benefit over electrical stimulation alone.

Association of Hearing Loss With PHACE Syndrome

PHACE syndrome describes a spectrum of anomalies associated with large facial infantile hemangiomas and characterized by posterior fossa malformations, hemangiomas, arterial anomalies, coarctation of the aorta and cardiac defects, and eye abnormalities. With improved recognition and imaging practices of infants with PHACE syndrome, additional associations have been identified. To our knowledge, the potential association of ipsilateral hearing loss and PHACE syndrome has not been previously emphasized. We describe 6 patients, 4 with definite and 2 with probable PHACE syndrome, according to the new diagnostic criteria, and associated auditory deficiencies. One patient had isolated conductive hearing loss; 2 patients had isolated sensorineural hearing loss; 1 patient had mixed hearing loss (both conductive and sensorineural components); and 1 patient had hearing loss that was inconclusive at the time. Also, 1 patient had conductive loss and auditory neuropathy and auditory dyssynchrony. Four of the 6 patients had magnetic resonance imaging features of lesions consistent with intracranial hemangiomas involving auditory structures. All 6 patients had facial hemangiomas in a nearly identical distribution ipsilateral to the ear with the hearing loss, with involvement of the proposed facial segments S1 and S3, the affected ear, the periauricular region, and the midoccipital area of the scalp. There is an underrecognized risk of hearing loss in patients with PHACE syndrome, although the exact nature of such deficiencies can vary. Patients with PHACE syndrome who have cutaneous hemangiomas involving the ear should be evaluated for intracranial hemangiomas and monitored for hearing loss. Early detection and therapy of intracranial hemangiomas may slow or stop tumor growth, resultant hearing loss, and structural damage.

Therapeutic approach to Gradenigo's syndrome: a case report

IntroductionTraditional management of Gradenigo's syndrome requires aggressive and radical surgery without any attempt to preserve hearing. Recent reports, however, describe a successful outcome after conservative surgical intervention without labyrinthectomy. A similar outcome has also been reported in patients who were only prescribed with antibiotics and did not undergo myringotomy.Case presentationWe report the case of a 24-year-old Caucasian Greek woman with Gradenigo's syndrome who was treated by draining her petrous apex via an infralabyrithine approach between her posterior semicircular canal and the jugular bulb. Her inner ear was not sacrificed during the procedure. She presented pre-operatively with ipsilateral conductive hearing loss, which recovered completely four weeks after the surgery.ConclusionsPatients with Gradenigo's syndrome may be successfully treated with a combination of long-term permanent drainage and ventilation of the apical cells with corresponding hearing preservation. This can be achieved via a combination of transmastoid, infralabyrinthine and suprajugular approaches, if such would be allowed by the anatomy of the region or if there is enough space between the posterior semicircular canal and the jugular bulb.

Microvascular decompression of the trigeminal nerve in the treatment of SUNCT and SUNA

BackgroundMedical management of short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) syndrome and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA) is often unsatisfactory.MethodsThe authors report...

The Transcrusal Approach

This study reviewed the experience and outcomes of 1 surgical team (L.S.P., S.P.L.) using the transcrusal approach. Ten-year retrospective review of 17 consecutive patients requiring transcrusal exposure of the petrous apex and upper brainstem was performed. The main outcome measures included hearing and facial nerve preservation as measured by standard audiography and postoperative assessment using the House-Brackmann scale. Operative indications included meningioma (5 patients), epidermoid/dermoid cyst (3 patients), trigeminal schwannoma (3 patients), giant or large upper basilar artery aneurysm (3 patients), pontine cavernoma (1 patient), chondrosarcoma (1 patient), and clival melanocytoma (1 patient). Average tumor size was 3.6 cm. Complete resection was achieved in 50% of patients with petroclival tumors. Follow-up data were obtained for 14 patients at 20 +/- 4 months. Serviceable hearing was preserved in 58%. Sixty-four percent of patients demonstrated House-Brackmann stage I facial nerve function. Two patients died perioperatively (brainstem infarction). Two patients became hemiparetic, with 1 improving substantially. CSF leaks developed in 3 patients. Forty-seven percent of patients demonstrated cranial nerve V deficits. Forty-one percent of patients demonstrated deficits of cranial nerve III, IV, or VI. Vertigo, vestibular disturbance, hydrocephalus, temporal lobe contusion, or hematoma did not develop in any patients. The transcrusal approach provides adequate exposure for most petroclival lesions and giant aneurysms of the upper basilar artery while offering the possibility of hearing preservation. Like all approaches to large tumors and aneurysms in this region, there is a significant risk of morbidity and mortality. However, this approach is an excellent alternative to other techniques that necessitate deliberate sacrifice of ipsilateral hearing.

Contralateral cochlear effects of ipsilateral damage: No evidence for interaural coupling

Lesion studies of the olivocochlear efferents have suggested that feedback via this neuronal pathway normally maintains an appropriate binaural balance in excitability of the two cochlear nerves ( Darrow et al., 2006). If true, a decrease in cochlear nerve output from one ear, due to conductive or sensorineural hearing loss, should change cochlear nerve response in the opposite ear via modulation in olivocochlear feedback. To investigate this putative efferent-mediated interaural coupling, we measured cochlear responses repeatedly from both ears in groups of mice for several weeks before, and for up to 5 weeks after, a unilateral manipulation causing either conductive or sensorineural hearing loss. Response measures included amplitude vs. level functions for distortion product otoacoustic emissions (DPOAEs) and auditory brainstem responses (ABRs), evoked at 7 log-spaced frequencies. Ipsilateral manipulations included either tympanic membrane removal or an acoustic overstimulation designed to produce a reversible or irreversible threshold shift over a restricted frequency range. None of these ipsilateral manipulations produced systematic changes in contralateral cochlear responses, either at threshold or suprathreshold levels, either in ABRs or DPOAEs. Thus, we find no evidence for compensatory contralateral changes following ipsilateral hearing loss. We did, however, find evidence for age-related increases in DPOAE amplitudes as animals mature from 6 to 12 weeks and evidence for a slow apical spread of noise-induced threshold shifts, which continues for several days post-exposure.

Quality of Life of Acoustic Neuroma Patients Treated with Gamma Knife Radiosurgery

Acoustic neuroma is a benign primary intracranial tumor of the vestibulocochlear nerve. The majority of patients present with ipsilateral sensineuronal hearing loss. Gamma knife radiosurgery is the principal alternative to microsurgical resection for acoustic neuromas. The goals of radiosurgery are prevention of tumor growth, maintenance of neurologic function, and prevention of new neurologic deficits. This review was performed to evaluate the efficacy of gamma knife radisosurgery for symptoms caused by acoustic neuroma and resulting quality of life. We evaluated 70 consecutive patients currently living treated with gamma knife radiosurgery for acoustic neuroma between 1995 and 2008. Baseline symptoms were collected from the time of procedure along with details of the treatment plan including dose to 50% isodose line, number of isocenters, and cubic centimeters treated. Patients were then contacted by phone and asked to report on changes in symptoms, new symptoms, new interventions, employment, and general quality of life. They were also evaluated using the Spitzer quality of life survey which consisted of five questions scored 0–2. The mean age of patients at time of procedure was 58 years (31–82). Thirty-four were male and thirty-six were female. There were 32 right-sided lesions and 38 left-sided lesions. Sixty patients received gamma knife as primary treatment and ten for recurrence. Treatment characteristics found a mean dose of 13.7 Gy (12–18), mean number of isocenters of 7 (1–20), and a mean volume treated of 1.96 cc (0.1–13.8). Presenting symptoms included ipsilateral hearing loss (93%), tinnitus (20%), pain (16%), numbness (14%), and dizziness (7%). Median time to phone follow-up was 73 months (5–158). Majority of patients reported their symptoms as same (57.1%) or better (32.9%). Six patients (8.6%) reported new symptoms after treatment and of these only one required medical intervention (medication for facial twitch). Thirty-nine patients (55.7%) were employed at the time of procedure and of these 89.7% continued to work on follow-up. Overall activity was reported as same in 87.1% of patients. When asked about overall quality of life, 48.6% reported it as same, 37.1% reported it as somewhat better, and 10% reported it as much better. The mean score for the Spitzer QOL survey was 9.56 out of 10. When asked about expectations and general satisfaction regarding the procedure, 93% of patients felt that gamma knife radiosurgery met their expectations and 93% of patients would recommend this as a primary treatment for acoustic neuroma. These findings suggest that gamma knife radiosurgery is an effective primary modality for the treatment of acoustic neuroma in terms of control of symptoms, improved quality of life, and general patient satisfaction.

Narrow Duplicated or Triplicated Internal Auditory Canal (3 Cases and Review of Literature)

The narrow duplicated internal auditory canal (IAC) is a very rare malformation, and there is no report about the narrow triplicated IAC in the literature. It has been believed to be associated with congenital sensorineural hearing loss and to be a result of aplasia or hypoplasia of the vestibulocochlear nerve or the cochlear branch. We present 2 cases of unilateral narrow duplicated IAC and 1 case of unilateral narrow triplicated IAC with ipsilateral sensorineural hearing loss. The separated, accessory bony canals delineated on high-resolution computed tomography do not mean the presence of nerve fibers. In previously presented cases and in our case, the separated small canals were vacant and without a cochlear nerve fiber. We present new common radiological findings as follows: the bony canal to the cochlea is very thin and the connection with the modiolus of the cochlea is interrupted in narrow separated IAC.

Histopathological and ultrastructural analysis of vestibular endorgans in Meniere's disease reveals basement membrane pathology.

BackgroundWe report the systematic analysis of the ultrastructural and cytological histopathology of vestibular endorgans acquired from labyrinthectomy in Meniere's disease.Methods17 subjects with intractable Meniere's disease and ipsilateral non-serviceable hearing presenting to the Neurotology Clinic from 1997 to 2006 who chose ablative labyrinthectomy (average age = 62 years; range 29–83 years) participated. The average duration of symptoms prior to surgery was 7 years (range 1–20 years).ResultsNearly all vestibular endorgans demonstrated varying degrees of degeneration. A monolayer of epithelial cells occurred significantly more frequently in the horizontal cristae (12/13 = 92%) (p < 0.001), the superior cristae (5/5 = 100%) (p < 0.005), the posterior cristae (2/2) compared with the utricular maculae (4/17 = 24%). Basement membrane (BM) thickening was more common in all of the cristae ampullares (18 out of 20) than the utricular maculae. Although only four saccular maculae were obtained, 3 out of 4 exhibited BM thickening and monolayer degeneration. Monolayer degeneration was highly significantly correlated with the presence of BM thickening (p < 0.001). Other degenerative changes noted equally among the five vestibular endorgans which were not significantly correlated with BM thickening or monolayer degeneration included hair cell vacuolization and stereocilia loss, microvesicles in the supporting cells, and increased stromal intercellular spaces. Transmission electron microscopy demonstrated disorganization of the BM collagen-like fibrils, and normal ultrastructural morphology of the nerve terminals and myelinated fibers. Stromal fibroblasts and endothelial cells of stromal blood vessels demonstrated vacuolization, and stromal perivascular BMs were also thickened.ConclusionSystematic histopathological analysis of the vestibular endorgans from Meniere's disease demonstrated neuroepithelial degeneration which was highly correlated with an associated BM thickening. Other findings included hair cell and supporting cell microvessicles, increased intercellular clear spaces in the stroma, and endothelial cell vacuolization and stromal perivascular BM thickening.

Hearing Conservation Surgery Using the Hybrid-L Electrode

Patients with high-frequency deafness and/or substantial residual hearing across frequencies might benefit from combined electro-acoustic stimulation. The Hybrid-L electrode was designed to address the issues of both hearing conservation and effective electrical stimulation in those recipients. The electrode with 22 contacts should be inserted through the round window membrane, and covers approximately 270° of the basal turn of the cochlear. This insertion length is equivalent to the one seen in many patients using the former Nucleus straight electrode. Twenty-four patients with low-frequency thresholds of 60 dB or better, up to 500 Hz, were implanted with a Hybrid-L device in a clinical trial at the Medical University of Hannover. Another group of 8 recipients with less residual hearing was included under extended inclusion criteria. Residual hearing was conserved in the majority of cases. One patient had a loss of more than 30 dB, but hearing partially recovered after 9 months. The median loss in all patients was 10 dB in both the Hybrid group and the extended group. Patients were able to use the residual hearing postoperatively to the same extent as preoperatively. In the Hybrid mode (cochlear implant + ipsilateral hearing aid), patients showed a significant improvement of 21% (p = 0.002) in speech understanding in quiet using the Freiburger Monosyllabic Word Test compared to the preoperative scores under aided conditions with their hearing aid. The Oldenburg Sentence Test in noise showed a remarkable average improvement of 10.2 dB (p < 0.001) compared to the preoperative hearing aid only mode. An additional improvement could be seen in the combined mode using an additional contralateral hearing aid. Recipients with a shorter duration of high-frequency hearing loss showed a larger benefit than those with a longer duration of hearing loss. Hearing conservation using the Hybrid-L electrode and a given surgical technique is possible with high probability in patients with high-frequency deafness or pantonal hearing loss. The use of the residual acoustic hearing offers specific advantages, especially for understanding speech in noise and for spatial hearing.

Radiosurgical treatment of vestibular schwannomas in patients with neurofibromatosis type 2

The radiosurgical treatment of vestibular schwannomas in patients with neurofibromatosis type 2 (NF2) is controversial. The authors investigated the radiologically proven tumor control rate after gamma knife radiosurgery. The factors that affect tumor control and serviceable hearing preservation were analyzed. Thirty-six lesions in 30 patients were included. The median lengths of the clinical and radiologic follow-ups were 48.5 months and 36.5 months, respectively. The median tumor volume was 3.2 cm3. The mean marginal dose was 12.1 grays (Gy) (range, 8-14 Gy) at an isodose line of 50%+/-0.6%. The Kaplan-Meier method and Cox proportional hazards model were used for the statistical analyses. The actuarial tumor control rate was 81%, 74%, and 66%, respectively, in the first, second, and fifth years. Five tumors required a salvage surgery because of tumor control failure. A low marginal dose and a young age at radiosurgery were associated with poor tumor control. Of the 16 tumors with which ipsilateral hearing was serviceable, the actuarial serviceable hearing preservation rates were 50%, 45%, and 33%, respectively, in the first, second, and fifth years. Better ipsilateral hearing (Gardner-Robertson grade 1, compared with grade 2) at the time of radiosurgery was associated with significantly greater serviceable hearing preservation. Gamma knife radiosurgery for vestibular schwannomas in NF2 patients provided 5-year tumor control in approximately two-thirds of patients and preserved serviceable hearing in approximately one-third. The rates of other cranial nerve deficits were low, and no secondary malignancy was observed. Radiosurgery should be included in treatment options for NF2 patients.

Speech enhancement with multichannel Wiener filter techniques in multimicrophone binaural hearing aids

This paper evaluates speech enhancement in binaural multimicrophone hearing aids by noise reduction algorithms based on the multichannel Wiener filter (MWF) and the MWF with partial noise estimate (MWF-N). Both algorithms are specifically developed to combine noise reduction with the preservation of binaural cues. Objective and perceptual evaluations were performed with different speech-in-multitalker-babble configurations in two different acoustic environments. The main conclusions are as follows: (a) A bilateral MWF with perfect voice activity detection equals or outperforms a bilateral adaptive directional microphone in terms of speech enhancement while preserving the binaural cues of the speech component. (b) A significant gain in speech enhancement is found when transmitting one contralateral microphone signal to the MWF active at the ipsilateral hearing aid. Adding a second contralateral microphone showed a significant improvement during the objective evaluations but not in the subset of scenarios tested during the perceptual evaluations. (c) Adding the partial noise estimate to the MWF, done to improve the spatial awareness of the hearing aid user, reduces the amount of speech enhancement in a limited way. In some conditions the MWF-N even outperformed the MWF possibly due to an improved spatial release from masking.

Congenital Unilateral Facial Palsy and Internal Auditory Canal Stenosis

Congenital stenosis of the internal auditory canal is a rare clinical entity. The majority of patients exhibit sensorineural hearing loss, and preserve facial-nerve function. We present a patient who manifested congenital unilateral facial palsy and ipsilateral sensorineural hearing loss clinically. Neuroimaging demonstrated stenosis of the unilateral internal auditory canal and hypoplasia of the ipsilateral trigeminal, facial, and vestibulocochlear nerves, despite normal function of the trigeminal nerves. The functional prognosis of facial and vestibulocochlear nerves was poor, and cognitive development demonstrated borderline delay.

Intracranial Primary Synovial Sarcoma: Radiologic-Pathologic Correlation

We present a very rare case of spontaneous intracranial synovial sarcoma. A 15-year-old female was admitted to our institution for a cervical spine MRI, reporting a gradual pain of the dorsal neck after an injury three months previously. After obtaining the first sequence we discovered a large skull base mass. We immediately performed a skull base MRI. MR arteriography, MR venography, CT and DSA were also performed. A large space-occupying lesion was demonstrated, extending from the right petrous bone to the occipital bone at the level of the foramen magnum and the right atlantooccipital junction. CT revealed calcifications. The MR venography demonstrated diminished flow in the right transverse and sigmoid sinus, as well in the right internal jugular vein. Otorhinolaryngological evaluation revealed a slight ipsilateral conductive hearing loss. The whole mass was macroscopically removed via a retrosigmoid, transmastoid, infratemporal approach. Postoperative course was uneventful, except for complete palsy of the ipsilateral hypoglossal nerve. The final pathological examination including immunohistochemical picture, showed findings consistent with synovial sarcoma (monophasic spindle-cell type).

Electric acoustic stimulation of the auditory system: results of a multi-centre investigation

Conclusion. A high rate of hearing preservation during cochlear implantation for electric acoustic stimulation (EAS) is possible, even when surgery is conducted by a number of different surgeons. Objectives. This study aimed to determine the degree of hearing preservation using surgery for EAS in a European multi-centre clinical investigation. It also aimed to demonstrate the effect of EAS in individuals with residual low frequency hearing, both on speech perception and on subjective quality of life measures. Patients and methods. Eighteen patients with profound high frequency hearing loss were recruited in five participating European centres. Subjects were assessed based on an audiologic test battery, as well as on a subjective hearing aid benefit questionnaire. Each subject underwent attempted hearing preservation cochlear implantation using the MED-EL C40+ device with a Medium electrode. Residual ipsilateral hearing and speech discrimination abilities were assessed at defined intervals up to 12 months after the combined electric-acoustic mode was introduced. Results. Results showed that some degree of hearing preservation was possible in 15718 patients. All subjects showed statistically significant benefit on all three speech perception tests over time. These significant benefits were also reflected in the subjective benefit outcomes.

Radiosurgery for Glomus Jugulare Tumors

Results for treating glomus jugulare tumors with radiosurgery have been limited by short follow-up and small number of patients. We report our experience using LINAC or CyberKnife in 21 tumors with a median follow-up of 66 months (Mean follow-up of 60 months). In addition, we have a subset of eight patients that were followed out for more than 10 years. Patients were treated with doses ranging from 1400 cGy to 2700 cGy. We retrospectively assessed patients for efficacy and post treatment side effects. All patients had stable neurological symptoms, and two patients experienced transient ipsilateral tongue weakness and hearing loss, both of which subsequently resolved. One patient experienced transient ipsilateral vocal cord paresis; however, this patient received previous external beam radiotherapy. All tumors remained stable or decreased in size by MRI exam. Our results support radiosurgery as an effective and safe method of treatment for glomus jugulare tumors with low morbidity as evidenced by a larger number of patients and long term follow-up.

STEREOTACTIC RADIOSURGERY FOR VESTIBULAR SCHWANNOMAS IN PATIENTS WITH NEUROFIBROMATOSIS TYPE 2

Vestibular schwannomas present significant management challenges in patients with neurofibromatosis Type 2 (NF2). We evaluated the results of gamma knife radiosurgery for the management of these tumors, focusing on tumor response, hearing preservation, and other factors affecting outcomes. Stereotactic radiosurgery was performed to manage 74 schwannomas in 62 patients. Ipsilateral serviceable hearing was present in 35% of tumors before the procedure. The mean tumor volume was 5.7 cm3. The mean margin and maximum dose used were 14 and 27.5 Gy, respectively. Cox regression analyses were performed to identify factors affecting outcomes. The median follow-up period was 53 months, and two patients were lost to follow-up. Actuarial local control rates at were 85, 81, and 81% at 5, 10, and 15 years, respectively. Tumor volume was significant as a predictor of local control. Since 1992, using current radiosurgery techniques (magnetic resonance imaging scan targeting and reduced margin dose to 14 Gy or less), the actuarial serviceable hearing preservation rate is 73% at 1 year, 59% at 2 years, and 48% at 5 years after radiosurgery. Facial neuropathy occurred in 8% of tumors, trigeminal neuropathy occurred in 4%, and vestibular dysfunction occurred in 4%. Radiation dose and tumor volume were predictive of development of new deficits. No radiosurgery-associated secondary tumors or atypical or malignant changes were noted. Stereotactic radiosurgery is a safe and effective management modality for neurofibromatosis Type 2 vestibular schwannomas. Although results do not seem to be as good as for patients with sporadic unilateral tumors, gamma knife radiosurgery results seem favorable and indicate that radiosurgery should be strongly considered for primary tumor management in selected patients.