Characteristics of 629 Vestibular Schwannomas According to Preoperative Caloric Responses

Preoperative cVEMP Results Predict Developing Prolonged Dizziness After Vestibular Schwannoma Surgery

OBJECTIVE

To assess pretreatment factors including preoperative vestibular function tests evaluated using cVEMP and caloric tests, which correlate with the development of prolonged dizziness after vestibular schwannoma resection.

STUDY DESIGN

Retrospective cohort study.

SETTING

Academic tertiary referral centers.

PATIENTS

Patients with vestibular schwannoma who underwent surgery and completed preoperative vestibular function tests and questionnaires.

INTERVENTION

Diagnostic.

MAIN OUTCOME MEASURES

Participants were divided into prolonged dizziness and nonprolonged dizziness groups according to their postoperative DHI scores. The rates of abnormal results of preoperative vestibular function tests (caloric test, cVEMP), including other factors such as preoperative HADS scores, were compared. Furthermore, univariate logistic regression analysis was performed with the DHI score at 3 months as the dependent variable.

RESULTS

Of the whole 45 participants, 14 (31%) developed prolonged dizziness postoperatively. The proportion of participants with abnormal cVEMP results was significantly lower in the prolonged dizziness group (7.1%) than in the nonprolonged dizziness group (42%). Other factors did not show any significant differences. Univariate analysis showed that only the cVEMP results correlated with the postoperative DHI score (OR = 9.39, 95% CI [1.56, 181.3], p < 0.05). About 70% of patients with prolonged dizziness continued to exhibit high DHI scores at 6 months after surgery; however, about half of them recovered by 1 year.

CONCLUSION

Vestibular schwannoma patients with normal preoperative cVEMP results tended to develop prolonged dizziness after resection compared to those with abnormal results. Preoperative cVEMP results enable physicians to predict whether vestibular schwannoma patients undergoing resection would likely develop prolonged dizziness postoperatively.

A Proposal for Comprehensive Audio-Vestibular Test Battery Protocol for Diagnosis and Follow-Up Monitoring in Patients with Vestibular Schwannoma Undergoing Surgical Tumor Removal

Background: A vestibular schwannoma (VS) is a benign tumor, causing audiological and vestibular symptoms. This study aimed to propose a comprehensive audio-vestibular test battery protocol for diagnosis and follow-up monitoring in patients with unilateral VSs undergoing surgical removal. Methods: The detailed interpretation of audiological and vestibular findings was presented in two example cases. The surgery was performed through the middle cranial fossa (#1) and translabyrinthine approach (#2). The participants were evaluated with tonal, speech, and impedance audiometry, ABR, caloric test, vHIT, cVEMP, oVEMP, SOT, and DHI. Patient and tumor characteristics were retrieved from the patient's history. Results: In the postoperative period, the reduction in gain of the lateral semicircular canal was observed in the vHITs of both patients. The DHI in case #1 increased after surgery, while it decreased in case #2. The improvement in postural performances compared to the preoperative SOT (CON 5, CON 6, composite score) and immediately after the procedure was observed. Conclusions: A specific diagnostic protocol is necessary to compare the results of different surgical techniques and approaches. Diagnostic tests performed before the surgery should be repeated within a specific time frame during postoperative follow-up to enable the comparison of results. The proposed protocol can help us better understand the processes ongoing during tumor growth and postoperative vestibular compensation.

Does Location of Intralabyrinthine Vestibular Schwannoma Determine Objective and Subjective Vestibular Function?

BACKGROUND AND OBJECTIVE

The incidence of intralabyrinthine schwannomas is increasing, and a growing attention is given to the detrimental effects on hearing function. On the contrary, the vestibular profile of intralabyrinthine vestibular schwannomas (VSs) is still not well understood. We aimed to investigate and report the observed relationships between the intralabyrinthine location of the schwannomas and objective and subjective vestibular profile of the patients.

METHODS

Retrospective cohort study of 20 consecutive individuals with sporadic intralabyrinthine schwannomas and grouped according to the intralabyrinthine location of the schwannomas. Vestibular testing consisted of the video head impulse test of all three semicircular canals, the caloric test, cervical and ocular vestibular evoked myogenic potentials, and the dizziness handicap inventory. A nonparametric unpaired t test was performed to compare groups, and Fisher's exact test was used for categorical data.

RESULTS

The median video head impulse test gains (lateral, anterior, posterior) were 0.40, 0.50, and 0.75 for intravestibular schwannomas and 0.93, 1.52, and 0.91 for intracochlear schwannomas ( p = 0.0001, p = 0.009, p = 0.33), respectively. Caloric unilateral weakness had a median of 100% for intravestibular schwannomas and 14% for intracochlear schwannomas ( p = 0.0001). The mean dizziness handicap inventory was 21 for intravestibular schwannomas and 1 for cochlear schwannomas ( p = 0.02). There were no significant differences in vestibular evoked myogenic potentials according to intralabyrinthine location.

CONCLUSION

By both objective and subjective measures, intralabyrinthine schwannomas with an intravestibular component has significantly worse vestibular function than schwannomas with purely cochlear involvement.

Vestibular Schwannoma: Long-term Outcome of the Vestibular Function After Stereotactic Radiosurgery

Objective

Evaluation at long term of the impact of the stereotactic surgery (SRS) on the vestibular function in vestibular schwannoma (VS) patients.

Study design and setting

Retrospective study in a tertiary referral center.

Patients

Fifty-one VS patients were included (34 females;17 males), aged from 41 to 78 years treated exclusively with SRS.

Intervention

Vestibular function was assessed before SRS and with median time interval of 14 (FU1) and 25 (FU2) months after treatment. Vestibular evaluation included: history, clinical vestibular examination, videonystagmography, head impulse test (v-HIT) and cervical vestibular evoked myogenic potentials (c-VEMPS).

Results

Before SRS, caloric testing (Caloric) was impaired in 77%; after treatment, in 92% (FU1) and 77% (FU2). Lateral HIT was decreased in 22% before SRS, in 39% at FU1 and FU2. C-VEMPS were absent in 50% before SRS, in 76% at FU1 and, FU2. Before SRS, no statistically significant association was found between asymptomatic and symptomatic patients with respect to the results of Caloric, v-HIT and c-VEMPS. This lack of association was also seen after SRS, at FU1 and FU2.

Conclusion

Our study showed that the impairment of the vestibular function might be attributed to the VS itself as well as to the radiation of the inner ear during SRS. The lateral SSC at low frequencies and the saccular function seem to be more involved with the time.

Vestibular Impairment in Patients with Vestibular Schwannoma: A Journey through the Pitfalls of Current Literature

Vestibular Schwannoma is the most common tumour of Ponto Cerebellar Angle and is capable of strongly impacting the patient's quality of life. In recent decades, the proposals for the management of the disease have multiplied, just as the diagnostic capacity has improved. While in the past, the primary objective was the preservation of the facial function, and subsequently also of the auditory function, the attention to the vestibular symptomatology, which appears to be one of the main indicators of deterioration of quality of life, is still unsatisfactory. Many authors have tried to provide guidance on the best possible management strategy, but a universally recognized guideline is still lacking. This article offers an overview of the disease and the proposals which have advanced in the last twenty years, evaluating their qualities and defects in a critical reading.

Impact of an Endolymphatic Sac Tumor on Subjective and Objective Audiovestibular Function

OBJECTIVE

This study reports subjective and objective audiovestibular function in patients diagnosed with an endolymphatic sac tumor (ELST), to evaluate the clinical implication of vestibular testing in ELST patients.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary referral center/university hospital.

PATIENTS

Five patients diagnosed with unilateral ELST.

INTERVENTION

Subjective and objective audiovestibular tests; pure-tone average; speech discrimination score; the Video Head Impulse Test; the cervical vestibular evoked myogenic potential test; the caloric irrigation test; the Speech, Spatial and Qualities of Hearing Scale; the Tinnitus Handicap Inventory; and the Dizziness Handicap Inventory.

MAIN OUTCOME MEASURE

Findings and characteristics of both subjective and objective audiovestibular functions.

RESULTS

The mean pure-tone average and the mean speech discrimination score were 49 dB HL and 68% on the tumor ear and 13 dB HL and 99% contralaterally. The mean Speech, Spatial and Qualities of Hearing Scale score was 84, and the mean Tinnitus Handicap Inventory score was 64. Caloric testing showed a mean unilateral weakness of 80%. The Video Head Impulse Test of the lateral semicircular canal revealed refixation saccades on all tumor ears and an average gain value of 0.75 on the tumor ear versus 0.94 contralaterally. No cervical vestibular evoked myogenic potentials were elicited on the tumor side, whereas all but one was elicited contralaterally. The average Dizziness Handicap Inventory score was 47.

CONCLUSION

A characteristic pattern of abnormal caloric findings, refixation saccades, and normal vestibulo-ocular reflex gain alongside sensorineural hearing loss on the tumor ear was identified. Asymmetric sensorineural hearing loss in any patient should lead to objective vestibular evaluation to strengthen not only a targeted tumor surveillance strategy and the indication for imaging, but also the design of vestibular rehabilitation. In addition, vestibular findings may guide the choice of surgical approach.

Evaluation of Vestibular Function in Diagnosis of Vestibular Schwannomas

Vestibular schwannomas (VS) are benign tumors of the vestibular nerve. The common first symptoms are hearing loss and tinnitus, followed by imbalance, vertigo, and facial nerve involvement. The subjective symptoms of VS patients are not consistent with the severity of vestibular lesions and the results of vestibular tests, which often interfere with clinicians' diagnoses. Thus, the main screening and diagnostic methods for VS are audiometry and magnetic resonance imaging (MRI), ignoring the evaluation of vestibular function at the source of pathological lesions. With the development and improvement of vestibular evaluation technology and its wide application in the clinic, modern vestibular examination technology can reflect the severity and frequency of vestibular lesions and compensation from multiple perspectives, providing an objective basis for the diagnosis and treatment of vestibular diseases. In this report, we review the results and characteristics of vestibular tests in VS patients and further clarify the clinical value of vestibular function assessment in the diagnosis and treatment of VS.

Video Head Impulse Test Results in Patients With a Vestibular Schwannoma-Sensitivity and Correlation With Other Vestibular System Function Tests, Hearing Acuity, and Tumor Size

OBJECTIVE

No previous studies have investigated a vestibular function test battery combining the Video Head Impulse Test (VHIT), the caloric test, and the cervical vestibular evoked myogenic potential (cVEMP) test. The objective was to investigate the sensitivity of the three vestibular tests to the presence of a vestibular schwannomas (VS), and possible correlations between test results, hearing acuity, and tumor size.

STUDY DESIGN

Retrospective cohort study.

SETTING

University hospital.

PATIENTS

Fifty-nine patients with a unilateral VS.

INTERVENTION

Audio-vestibular tests; the VHIT, cVEMP, caloric irrigation, pure-tone audiometry, and speech discrimination.

MAIN OUTCOME MEASURE

Findings, sensitivity, and correlations between VHIT saccades and gain; cVEMP potentials, unilateral caloric weakness; hearing acuity.

RESULTS

The sensitivity for VS was 80% for the VHIT, 93% for the caloric test, and 73% for the cVEMP test. VHIT gain and saccades were associated, and both had a positive correlation to caloric function. Medium-sized tumors demonstrated the highest gain asymmetry while larger tumors were associated with saccades. There was a weak correlation between vestibular findings and hearing acuity.

CONCLUSION

The VHIT is sensitive to the occurrence of a VS, but less so than the caloric test, and vestibular function deteriorates to some extent with increasing tumor size. VHIT outcomes are positively correlated to caloric function, but only vaguely to cVEMP and hearing acuity. The combined vestibular function test battery reached a sensitivity of 97% to the occurrence of a VS and could thus potentially substitute MRI for tumor screening upon the diagnosis of an asymmetrical hearing loss.

MRI monitoring of small and medium-sized vestibular schwannomas: predictors of growth

Background: Vestibular schwannomas are among the most common intracranial tumours. Their growth is difficult to predict.Objectives: To study the evolution of small and medium-sized vestibular schwannomas (VSs) and identify factors predictive of growth.Material and methods: This was a retrospective longitudinal study at a tertiary referral centre from January 2011 to January 2018. The inclusion criteria were radiological diagnosis of sporadic unilateral VS of stage I or II. Radiological and clinical data were analysed descriptively and by multivariate logistic regression to identify factors predictive of growth.Results: A total of 1105 cases were discussed in multidisciplinary meetings and 336 patients were included with a mean age of 57.8 years and a mean follow-up time of 24 months. Around two thirds of these patients (62.8%) had non-progressive tumours. Factors identified as predictive of VS growth were the size at diagnosis (OR = 2.622, 95% CI, 1.50-4.66; p = .001) and internal auditory canal filling (OR = 7.672; 95% CI, 4.52-13.43; p < .001).Conclusions and significance: Monitoring is the primary treatment modality for small or medium-sized VSs. As reported here for the first time, internal auditory canal filling is significantly associated with VS growth.

Long-term Effects of Conservative Management of Vestibular Schwannoma on Dizziness, Balance, and Caloric Function

Objectives

To study the development of dizziness, caloric function, and postural sway during long-term observation of untreated vestibular schwannoma patients.

Study Design

Retrospective review of a prospectively maintained longitudinal cohort.

Setting

Tertiary referral hospital.

Subjects and Methods

Patients with vestibular schwannoma undergoing wait-and-scan management were included—specifically, those who did not require treatment during a minimum radiologic follow-up of 1 year. Baseline data and follow-up included magnetic resonance imaging, posturography, bithermal caloric tests, and a dizziness questionnaire. Main outcomes were prevalence of moderate to severe dizziness, canal paresis, and postural instability at baseline and follow-up, as compared with McNemar’s test.

Results

Out of 433 consecutive patients with vestibular schwannoma, 114 did not require treatment during follow-up and were included. Median radiologic follow-up was 10.2 years (interquartile range, 4.5 years). Age ranged from 31 to 78 years (mean, 59 years; SD, 10 years; 62% women). Median tumor volume at baseline was 139 mm3(interquartile range, 314 mm3). This did not change during follow-up ( P = .446). Moderate to severe dizziness was present in 27% at baseline and 19% at follow-up ( P = .077). Postural unsteadiness was present in 17% at baseline and 21% at follow-up ( P = .424). Canal paresis was present in 51% at baseline and 56% at follow-up ( P = .664).

Conclusions

There was no significant change in the prevalence of dizziness, postural sway, or canal paresis during conservative management of vestibular schwannoma, while tumor volume remained unchanged. This indicates a favorable prognosis in these patients with regard to vestibular symptoms.

Audiovestibular Loss of Function Correlates in Vestibular Schwannomas

OBJECTIVES

The aim of the present study was to investigate the relationships between tumor size, hearing, and vestibular outcomes in patients with vestibular schwannomas (VSs).

MATERIALS AND METHODS

Adult patients (n=124) with unilateral extrameatal VS prior to surgery were included in the study. This was a retrospective cohort study of preoperative audiovestibular investigations including audiometry, discrimination test, caloric test, cervical vestibular evoked myogenic potential (c-VEMP), and ocular vestibular evoked myogenic potential (o-VEMP).

RESULTS

The difference between lesioned and non-lesioned ear was significant for all audiovestibular outcomes. The mean caloric deficit was 74%. No tumor sided o-VEMPs were elicited. Caloric deficit correlated with hearing loss measured with pure tone average and discrimination score. c-VEMP deficit was significantly associated with severe hearing loss and larger tumors.

CONCLUSION

The presence of VS leads to a significant deterioration of audiovestibular function in all objective measures. Caloric test and o-VEMPS are sensitive though unspecific measures of VSs. Increasing tumor size is not directly associated with hearing loss and only somewhat to vestibular deficit. However, audiovestibular findings are correlated.

Cross Sectional Imaging of the Ear and Temporal Bone

CT and MR imaging are essential cross-sectional imaging modalities for assessment of temporal bone anatomy and pathology. The choice of CT versus MR depends on the structures and the disease processes that require assessment, delineation, and characterization. A thorough knowledge of the two imaging modalities' capabilities and of temporal bone anatomy greatly facilitates imaging interpretation of pathologic conditions.

Surgical treatment of lateral skull base lesions and reconstruction of the skull base: a report of 20 cases

OBJECTIVE

To investigate the surgical treatment and related experience of lateral skull base lesions.

METHODS

In a retrospective, clinical data analysis of 20 patients with lateral skull base diseases, 11 cases with temporal bone space-occupying lesions and intracranial invasion were treated by translabyrinthine surgery, mastoid cavity drainage, or transmastoid surgery to remove the lesion; two cases of cholesteatoma with destruction of tympanic cavity and tympanic sinus canopy with intracranial invasion were treated by extended radical mastoidectomy; seven cases with lateral skull base bone destruction with cerebrospinal fluid otorrhea caused by trauma and deformity were treated by translabyrinth and transmastoid repair.

RESULTS

Eleven cases with temporal bone space occupying lesions were resected completely and were without recurrence after surgery. Two cases with intracranial infection secondary to cholesteatoma were rapidly relieved of symptoms without recurrence after radical mastoidectomy. The remaining seven cases of CSF otorrhea included two cases of Mondini malformation and five cases of temporal bone fracture. The leak was stemmed in all seven cases after surgery.

CONCLUSION

Surgery is the main therapeutic option for the treatment of lateral skull base diseases. The surgical approach and the type of skull base reconstruction should be selected on an individual case-by-case basis.

Audiovestibular Function Deficits in Vestibular Schwannoma

Introduction. Vestibular schwannomas (VS) are benign tumours of the vestibular nerve and can lead to hearing loss, tinnitus, vertigo, facial palsy, and brainstem compression. Audiovestibular diagnostic tests are essential for detection and treatment planning. Methods. Medline was used to perform a systematic literature review with regard to how audiovestibular test parameters correlate with symptoms, tumour size, and tumour location. Results. The auditory brainstem response can be used to diagnose retrocochlear lesions caused by VS. Since hearing loss correlates poorly with tumour size, a retrocochlear lesion is probably not the only cause for hearing loss. Also cochlear mechanisms seem to play a role. This can be revealed by abnormal otoacoustic emissions, despite normal ABR and new MRI techniques which have demonstrated endolymphatic hydrops of the inner ear. Caloric and head impulse tests show frequency specific dynamics and vestibular evoked myogenic potentials may help to identify the location of the tumour regarding the involved nerve parts. Conclusion. In order to preserve audiovestibular function in VS, it is important to stop the growth of the tumour and to avoid degenerative changes in the inner ear. A detailed neurotological workup helps to diagnose VS of all sizes and can also provide useful prognostic information.

Tympanomastoid cholesterol granuloma: radiological and intraoperative findings of blood source connection

The hypothesis that the close contiguity between the cholesterol granulomas and some rich blood sources provided the trigger to the aggressive nature of tympanomastoid cholesterol granulomas has been recently reported. To corroborate this new etiopathogenetic theory we retrospectively reviewed a series of 14 patients with primary middle ear and mastoid cholesterol granulomas and investigated the temporal bone marrow invasion and its hematopoietic potentialities and a possible cholesterol granulomas contiguity with relevant vascular structures such as the carotid artery, sigmoid jugular system, mastoid or dural vein. Eight cases did not show radiological sign of bone marrow invasion or hematopoietic potentialities visible in MRI. Besides no intraoperative vascular connections that could explain an initial bleeding source were found. Cholesterol granulomas bone marrow invasion was present in six patients. A bone marrow hematopoietic potentiality was showed in four of these patients, whereas, an evident anatomical contiguity of the cholesterol granuloma with some important temporal bone vascular structures was visible in five cases. Analysis of cardiovascular risk factors showed that four patients presented one or more of the risk factors analysed.

Preoperative balance control compensation in patients with a vestibular schwannoma: does tumor size matter?

OBJECTIVE

The influence of tumor size on postural control of patients with vestibular schwannoma (VS) remains to be determined. This study aimed to compare the postural performances of VS patients, according to the size of the tumor, with healthy subjects.

METHODS

The six conditions (C1-C6) of the sensory organization test (SOT) were carried out in 87 patients, split into four groups according to the Koos classification (stage I-IV), and in 72 aged-matched controls to evaluate postural control. The vestibular reflectivity and compensation were estimated with videonystagmography.

RESULTS

Among patients, lower C5 and C6 scores were found in stage I and IV patients than in stage II and III patients, whereas vestibular compensation did not impact the tumor size influence on the postural control. The scores were significantly (p<0.001) lower for all the groups of patients than the controls in the vestibular-related SOT conditions (C5-C6).

CONCLUSIONS

Patients with an unilateral VS displayed altered postural performances compared to the control subjects and tumor size had a bell-like pattern effect on balance control.

SIGNIFICANCE

The tumor size could be seen as a determining factor in the implementation of adaptive mechanisms that lead to the postural compensation and might be dissociated from vestibular compensation.

Horizontal VOR function shows frequency dynamics in vestibular schwannoma

The objective of this retrospective study was to investigate the horizontal vestibulo-ocular reflex (hVOR) pathway with caloric test (low-frequency hVOR) and video head impulse test (vHIT) (high-frequency hVOR) in patients with sporadic vestibular schwannoma (69 patients, 27-86 years, mean age 58.1 years) and to compare both test methods in terms of their sensitivity and specificity to detect a retrocochlear lesion. Test results with a unilateral weakness (UWCaloric) >25 % (caloric test) or a Mean-GainvHIT <0.79/asymmetry ratio of Gain (AR-GainvHIT) >8.5 % and accompanied refixation saccades (vHIT) were considered abnormal. The overall sensitivity of the caloric test was 72 %. The evaluation of AR-GainvHIT detected more abnormal cases than did Mean-GainvHIT (44 vs. 36 %). In up to 4 %, a normal caloric test result was related to an abnormal vHIT. There was only a moderate correlation of UWCaloric and AR-GainvHIT (r = 0.54, p < 0.05) with a linear regression line intercept/slope of 32.2/0.9 (p < 0.05). Receiver operating characteristics curve analysis exhibited at a UWCaloric of 50 % a vHIT sensitivity/specificity/positive predictive value/negative predictive value of 0.45/0.9/0.94/0.42. Vestibular testing at varying frequencies provides deeper insights into hVOR function and is helpful in detecting a cerebello-pontine lesion. Whereas caloric test yields a high sensitivity for nerve dysfunction, vHIT test reveals a remaining function of hVOR in the high-frequency range.

Asymmetry of balance responses to monaural galvanic vestibular stimulation in subjects with vestibular schwannoma

OBJECTIVE

We investigated the potential of galvanic vestibular stimulation (GVS) to quantify lateralised asymmetry of the vestibulospinal pathways by measuring balance responses to monaural GVS in 10 subjects with vestibular schwannoma and 22 healthy control subjects.

METHODS

Subjects standing without vision were stimulated with 3 s, 1 mA direct current stimuli delivered monaurally. The mean magnitude and direction of the evoked balance responses in the horizontal plane were measured from ground-reaction forces and from displacement and velocity of the trunk. Vestibular-evoked myogenic potentials (VEMPs) to 500 Hz air and bone-conducted tones were also recorded.

RESULTS

In healthy subjects, the magnitudes of the force, velocity and displacement responses were not significantly different for left compared to right ear stimulation. Their individual asymmetry ratios were always < 30%. Subjects with vestibular schwannoma had significantly smaller force, velocity and displacement responses to stimulation of the affected compared with non-affected ear. Their mean asymmetry ratios were significantly elevated for all three measures (41.2 ± 10.3%, 40.3 ± 15.1% and 21.9 ± 14.6%).

CONCLUSIONS

Asymmetry ratios of balance responses to monaural GVS provide a quantitative and clinically applicable lateralising test of the vestibulospinal pathways.

SIGNIFICANCE

This method offers a more clinically relevant measure of standing balance than existing vestibular function tests which assess only vestibuloocular and vestibulocollic pathways.

Vestibular compensation after vestibular schwannoma surgery: normalization of the subjective visual vertical and disability

CONCLUSIONS

The degree of caloric weakness before surgery influences faster or slower recovery of patients undergoing vestibular schwannoma surgery. The Dizziness Handicap Inventory (DHI) is a good index to show the recovery of patients as it relates directly to an improvement or not of the subjective visual vertical (SVV).

OBJECTIVE

To evaluate the process of recovery of patients as measured by the SVV and the DHI after surgical removal of vestibular schwannoma.

METHODS

We studied 24 consecutive patients of the University Hospital of Salamanca who underwent vestibular schwannoma surgery. We assessed age, tumour size, degree of canalicular weakness and preoperative SVV, and their relationship with DHI and SVV at discharge and also at 1, 3 and 6 months postoperatively.

RESULTS

Patients with lesser degrees of caloric weakness took longer to normalize SVV than those with a higher caloric weakness before surgery (p < 0.05). There was a significant correlation between DHI and improvements in SVV with time. The differences disappeared in 6 months where all patients, with greater or lesser degree of caloric weakness, had the same results.

Neurophysiologic, audiometric and vestibular function tests in patients with hyperostosis cranialis interna

OBJECTIVE

Hyperostosis cranialis interna (HCI) is an autosomal dominant sclerosing bone dysplasia affecting the skull base and the calvaria, characterized by cranial nerve deficits due to stenosis of neuroforamina. The aim of this study is to describe the value of several neurophysiological, audiometric and vestibular tests related to the clinical course of the disorder.

METHODS

Ten affected subjects and 13 unaffected family members were recruited and tested with visual evoked potentials, masseter reflex, blink reflex, pure tone and speech audiometry, stapedial reflexes, otoacoustic emissions, brainstem evoked response audiometry and electronystagmography.

RESULTS

Due to the symmetrical bilateral nature of this disease, the sensitivity of visual evoked potentials (VEPs), masseter reflex and blink reflex is decreased (25-37.5%), therefore reducing the value of single registration. Increased hearing thresholds and increased BERA latency times were found in 60-70%. The inter-peak latency I-V parameter in BERA has the ability to determine nerve encroachment reliably. 50% of the patients had vestibular abnormalities. No patient had disease-related absence of otoacoustic emissions, because the cochlea is not affected.

CONCLUSION

In patients with HCI and similar craniofacial sclerosing bone dysplasias we advise monitoring of vestibulocochlear nerve function with tone and speech audiometry, BERA and vestibular tests. VEPs are important to monitor optic nerve function in combination with radiological and ophthalmologic examination. We do not advise the routine use of blink and masseter reflex.

Hearing preservation: microsurgery

PURPOSE OF REVIEW

To evaluate the recent and significant contributions to the literature that examine hearing preservation outcomes and prognostic factors in vestibular schwannoma microsurgery.

RECENT FINDINGS

Hearing preservation rates overall range considerably between 2 and 93% in recent studies. There are a number of factors that have been reported to be significant in the prediction of hearing preservation. Characteristics such as approach, results of preoperative neurophysiological testing, tumor size and nerve of origin have long been reported. A more recent contribution to the literature has included the association between MRI T2 signal in the fundus of the internal auditory canal and hearing preservation. This review provides a summary of some of the landmark studies in conjunction with more recent work detailing the prognostic factors for hearing preservation in the surgical management of vestibular schwannoma.

SUMMARY

Hearing preservation in vestibular schwannoma surgery has undergone tremendous evolution over the past 50 years. In this review, we outline the prognostic factors that predict hearing preservation and describe recent contributions.

The totally implantable middle ear device 'Esteem' for rehabilitation of severe sensorineural hearing loss

CONCLUSION

The Esteem(®) device proved to offer beneficial results in subjects suffering from high frequency, severe bilateral sensorineural hearing loss (SNHL) and may be considered as an alternative procedure to conventional hearing aids (HAs) or electroacoustic stimulation (EAS) systems.

OBJECTIVES

Since the Esteem(®) totally implantable device has been shown to offer positive results among patients with moderate SNHL, this middle ear implant has also been suggested for subjects with a worse degree of hearing loss in order to predict its extended application, also in the nearly cochlear implantation range.

METHODS

Esteem(®) implantation was carried out in 21 subjects with a mild (n = 3), moderate (MHL, n = 9) or severe (SHL, n = 9) degree of SNHL. The two latter groups, i.e. MHL and SHL, were compared in terms of preoperative versus postoperative pure tone and speech reception thresholds (SRTs). Similarly, they were also compared for the outcome from quality of life (QoL) questionnaires, such as the general Glasgow Benefit Inventory (GBI) and COSI.

RESULTS

In the whole sample, mean hearing threshold levels improved from 70 to 48 dB; in the MHL group the mean hearing threshold level improved from 64 to 42 dB; in the SHL group the mean hearing threshold level improved from 82 to 58 dB. GBI and COSI scores were only slightly better in the MHL group than in the SHL group.

Intraoperative adjustments to optimize active middle ear implant performance

CONCLUSION

After initial contact of the active middle ear implant (AMEI) on the incus, significant increases in device performance can be achieved intraoperatively without affecting residual hearing by additional static loading of the incus with 62 μm (quarter turn) to 125 μm (half turn) increments via an adjustment screw.

OBJECTIVES

To assess the performance gains of driving the incus with an AMEI under increasing static loads in cadaveric temporal bones.

METHODS

Incus drive efficacy was assessed using laser Doppler velocimetry measurements of stapes velocities over a frequency range of 0.25 to 8 kHz. Results were compared to stapes velocities following acoustic stimulation via insert earphone. Maximum equivalent ear canal sound pressure level (L(Emax)) and residual hearing loss after initial loading of the AMEI (first contact) were compared in each temporal bone. Additional increases in incus load were induced by turning an adjustment screw in quarter turn steps, corresponding to 62 μm increments per step. L(Emax)and residual hearing loss were reassessed after each step. For each temporal bone, experiments were repeated for three different AMEIs.

RESULTS

On average across bones, incus stimulation upon initial contact produced an L(Emax)of 125, 127, and 121 dB SPL and residual hearing losses of -2, -1, and -1 dB with respect to unloaded, unaided conditions for the three AMEIs, respectively. Across bones and transducers, increasing static transducer load by incrementing the AMEI up to 125 μm significantly improved performance without affecting residual hearing loss. Loading beyond 125 μm (half turn) did not improve performance but significantly increased residual hearing loss.