Angular vestibulo-ocular reflex gains correlate with vertigo control after intratympanic gentamicin treatment for Meniere's disease

Efficacy and preservation of hearing with low-dose gentamicin in unilateral meniere's disease: A clinical symptomatology-based study

PURPOSE

Meniere's disease (MD), a disorder of the inner ear, presents numerous therapeutic challenges, and intratympanic (IT) gentamicin has been proposed for intractable cases. However, controversy regarding dosage and method persists. The purpose of this study was to assess the efficacy and safety of low-dose IT gentamicin on vertigo attacks in MD using a clinical symptomatology-based method, wherein administration was repeated only if vertigo attacks recurred, with a 2-week interval between injections.

MATERIALS AND METHODS

This study included 88 patients with unilateral intractable MD. All patients received one to five IT injections with 0.5 ml of 10 mg of gentamicin (80 mg/2 ml) with an interval of 2 weeks between injections. Vertigo attacks were evaluated before and after therapy and categorized into classes A-F according to the 2015 Equilibrium Committee criteria. Audiovestibular assessments, including Pure Tone Audiometry and Vestibulo-Ocular Reflex evaluations, were performed.

RESULTS

Before treatment, patients had an average of 4.4 vertigo attacks/month; after treatment, this average decreased to 0.52. The majority of patients (57 %) reached Class A or B vertigo control with five or fewer gentamicin injections. VOR gain was slightly affected on the healthy side and significantly reduced on the affected side. No hearing deterioration was found in any of the treated patients.

CONCLUSIONS

Low-dose IT gentamicin administration based on clinical symptomatology can produce a satisfactory control of vertigo attacks after treatment. This protocol primarily affected the vestibular function, as demonstrated by the significant reduction in VOR gain on the affected side, while avoiding cochlear damage. The lack of adverse events and preservation of hearing underscore the safety and efficacy of this method. These findings have significant clinical implications, suggesting that a low-dose, clinical symptomatology-based gentamicin treatment regimen could be an effective and safe strategy for managing unilateral Meniere's disease in a larger population.

Low-Dose Intratympanic Gentamicin for Unilateral Ménière‘s Disease: Accuracy of Early Vestibulo-Ocular Reflex Gain Reduction in Predicting Long-Term Clinical Outcome

Background

The number of intratympanic gentamicin (ITG) injections needed to achieve vertigo control in patients with intractable Ménière's disease (MD) may vary from a single dose to several instillations. Changes in different vestibular test results have been used to define an endpoint of treatment, including the decrease of the vestibulo-ocular reflex (VOR) gain elicited by the head-impulse test.

Objective

To assess the accuracy of the VOR gain reduction after horizontal canal stimulation, as measured with the video head-impulse test (vHIT) 1 month after the first intratympanic injection, in predicting the need for one or more instillations to control vertigo spells in the long term.

Methods

The VOR gain reduction was calculated in 47 patients submitted to (ITG) therapy 1 month after the first instillation.

Results

Single intratympanic treatment with gentamicin has a 59.6% efficacy in vertigo control in the long term. Hearing change in the immediate period after treatment (1 month) is not significant to pre-treatment result and is similar for patients who needed multiple doses due to recurrence. Chronic disequilibrium and the need for vestibular rehabilitation were less frequent in patients with a good control of vertigo with just one single injection of gentamicin. A fair accuracy was obtained for the VOR gain reduction of the horizontal canal (area under the curve = 0.729 in the Receiver Operating Characteristic analysis) in predicting the need for one or more ITG.

Conclusions

Single intratympanic treatment with gentamicin is an effective treatment for patients with MD. That modality of treatment has very limited damaging effect in hearing. The degree of vestibular deficit induced by the treatment is significant as measured by the reduction in the gain of the VOR but not useful for prognostic purposes.

Pre-habilitation Before Vestibular Schwannoma Surgery-Impact of Intratympanal Gentamicin Application on the Vestibulo-Ocular Reflex

Background: Patients with vestibular schwannoma that show residual peripheral-vestibular function before surgery may experience sudden and substantial vestibular loss of function after surgical resection. To alleviate the sudden loss of peripheral-vestibular function after vestibular-schwannoma (VS) resection, pre-surgical intratympanic gentamicin application was proposed. Objective: We hypothesized that this approach allows for a controlled reduction of peripheral-vestibular function before surgery but that resulting peripheral-vestibular deficits may be canal-specific with anterior-canal sparing as observed previously in systemic gentamicin application. Methods: Thirty-four patients (age-range = 27-70 y) with unilateral VS (size = 2-50 mm) were included in this retrospective single-center trial. The angular vestibulo-ocular reflex (aVOR) was quantified before and after (29.7 ± 18.7 d, mean ± 1SD) a single or two sequential intratympanic gentamicin applications by use of video-head-impulse testing. Both aVOR gains, cumulative saccadic amplitudes, and overall aVOR function were retrieved. Statistical analysis was done using a generalized linear model. Results: At baseline, loss of function of the horizontal (20/34) and posterior (21/34) canal was significantly (p < 0.001) more frequent than that of the anterior canal (5/34). After gentamicin application, loss of function of the horizontal (32/34) or posterior (31/34) canal remained significantly (p ≤ 0.003) more frequent than that of the anterior canal (18/34). For all ipsilesional canals, significant aVOR-gain reductions and cumulative-saccadic-amplitude increases were noted after gentamicin. For the horizontal canal, loss of function was significantly larger (increase in cumulative-saccadic-amplitude: 1.6 ± 2.0 vs. 0.8 ± 1.2, p = 0.007) or showed a trend to larger changes (decrease in aVOR-gain: 0.24 ± 0.22 vs. 0.13 ± 0.29, p = 0.069) than for the anterior canal. Conclusions: Intratympanic gentamicin application resulted in a substantial reduction in peripheral-vestibular function in all three ipsilesional canals. Relative sparing of anterior-canal function noted at baseline was preserved after gentamicin treatment. Thus, pre-surgical intratympanic gentamicin is a suitable preparatory procedure for reducing the drop in peripheral-vestibular function after VS-resection. The reasons for relative sparing of the anterior canal remain unclear.

Sparse classification of discriminant nystagmus features using combined video-oculography tests and pupil tracking for common vestibular disorder recognition

Vertigo is a common sign related to a problem with the brain or vestibular system. Detection of ocular nystagmus can be a support indicator to distinguish different vestibular disorders. In order to get reliable and accurate real time measurements from nystagmus response, video-oculography (VOG) plays an important role in the daily clinical examination. However, vestibular diseases present a large diversity in their characteristics that leads to many complications for usual analysis. In this paper, we propose a novel automated approach to achieve both selection and classification of nystagmus parameters using four tests and a pupil tracking procedure in order to give reliable evaluation and standardized indicators of frequent vestibular dysfunction that will assist clinicians in their diagnoses. Indeed, traditional tests (head impulse, caloric, kinetic and saccadic tests) are applied to obtain clinical parameters that highlight the type of vertigo (peripheral or central vertigo). Then, a pupil tracking method is used to extract temporal and frequency nystagmus features in caloric and kinetic sequences. Finally, all extracted features from the tests are reduced according to their high characterization degree by linear discriminant analysis, and classified into three vestibular disorders and normal cases using sparse representation. The proposed methodology is tested on a database containing 90 vertiginous subjects affected by vestibular Neuritis, Meniere's disease and Migraines. The presented technique highly reduces labor-intensive workloads of clinicians by producing the discriminant features for each vestibular disease which will significantly speed up the vertigo diagnosis and provides possibility for fully computerized vestibular disorder evaluation.

Dissociation of Caloric and Video Head Impulse Tests in Patients With Delayed Endolymphatic Hydrops

Delayed endolymphatic hydrops (DEH) represents a rare clinical entity characterized by intermittent vertigo attacks mimicking those of Ménière's disease (MD) in a patient with a prior sensorineural hearing loss. Some vestibular tests have been employed in patients with DEH. These tests provide useful diagnostic information and facilitate clinical decision-making. Here, we retrospectively studied the features of video head impulse test (vHIT) and examined its relationship with caloric test used in DEH patients. Included in this study were 17 patients with ipsilateral DEH and 2 with contralateral DEH. Among them, 73.7% (14/19) showed abnormal caloric test response (76.5% in ipsilateral DEH and 50% in contralateral DEH). Meanwhile, only 15.8% (3/19) of patients yielded abnormal horizontal vHIT results (11.8% in ipsilateral DEH and 50% in contralateral DEH). Abnormal caloric response in the presence of a preserved vHIT was common in DEH patients, especially those with ipsilateral DEH. This dissociation might be a distinctive pattern of vestibular deficit in DEH.

Change of VOR gain and pure-tone threshold after single low-dose intratympanic gentamicin injection in Meniere's disease

Background: Intratympanic gentamicin injection (ITG) is a well-accepted means to treat intractable Meniere's disease (MD).Aims/Objectives: To investigate change of vestibule-ocular reflex (VOR) gain and pure-tone threshold after low-dose ITG for MD.Methods: Sixteen patients with definite MD who were treated by low-dose ITG were retrospectively reviewed. We defined VOR gain difference as an amount of decreased gain in video head impulse test one month after ITG. Patients were classified into two groups: single injection vs. multiple injections. Multiple injections group was composed of patients with poor vertigo control after initial ITG who required second or third ITG later in follow up period.Results: VOR gain differences of both horizontal and posterior canal plane were higher than those of anterior canal plane. Between two groups, mean VOR gain difference of horizontal canal plane in multiple injections group was lower than that in single injection group. Only two patients showed increased pure-tone threshold more than 10 dB.Conclusion and significance: Our results suggest that ITG appears to cause a differential loss of function across three semicircular canals. Furthermore, if VOR gain difference of horizontal canal is relatively low after initial ITG, patient might have poor vertigo control and be required another ITG.

Low-dose intratympanic gentamicin administration for unilateral Meniere's disease using a method based on clinical symptomatology: Preliminary results

PURPOSE

There are many therapeutic options for Meniere's disease (MD); intratympanic (IT) gentamicin has been proposed for intractable cases although controversy about dosage and method exists. The purpose of this study was to assess the efficacy and safety of low-dose IT gentamicin on vertigo attacks in MD using a clinical symptomatology-based method in which administration was repeated only if vertigo attacks recurred, with a 2-week interval between injections.

MATERIALS AND METHODS

Forty-eight patients with unilateral intractable MD were included in the study. All patients received one to five IT injections with 0.5 ml of 10 mg of gentamicin (80 mg/2 ml) with an interval of 2 weeks between injections. Vertigo attacks were evaluated before and after therapy and categorized into classes A-F according to the 2015 Equilibrium Committee criteria. Audiovestibular assessment with pure tone audiometry, vestibular bed-side examination and video head impulse test was performed.

RESULTS

Before treatment patients had an average of 4.4 vertigo attacks/month; after treatment the average number decreased to 0.52. The majority of patients (77%) reached Class A vertigo control with 5 or less gentamicin injections. VOR gain was unaffected in the healthy side and significantly reduced in the affected side. No hearing deterioration was found in all treated patients.

CONCLUSIONS

Low-dose IT gentamicin administration based on clinical symptomatology can produce a satisfactory control of vertigo attacks after treatment; such protocol had an effect mainly on the vestibular function as demonstrated by the significant reduction in VOR gain in the affected side avoiding a cochlear damage.

Artificial intelligence for understanding concussion: Retrospective cluster analysis on the balance and vestibular diagnostic data of concussion patients

OBJECTIVES

We propose a bottom-up, machine-learning approach, for the objective vestibular and balance diagnostic data of concussion patients, to provide insight into the differences in patients' phenotypes, independent of existing diagnoses (unsupervised learning).

METHODS

Diagnostic data from a battery of validated balance and vestibular assessments were extracted from the database of the Swiss Concussion Center. The desired number of clusters within the patient database was estimated using Calinski-Harabasz criteria. Complex (self-organizing map, SOM) and standard (k-means) clustering tools were used, and the formed clusters were compared.

RESULTS

A total of 96 patients (81.3% male, age (median [IQR]): 25.0[10.8]) who were expected to suffer from sports-related concussion or post-concussive syndrome (52[140] days between diagnostic testing and the concussive episode) were included. The cluster evaluation indicated dividing the data into two groups. Only the SOM gave a stable clustering outcome, dividing the patients in group-1 (n = 38) and group-2 (n = 58). A large significant difference was found for the caloric summary score for the maximal speed of the slow phase, where group-1 scored 30.7% lower than group-2 (27.6[18.2] vs. 51.0[31.0]). Group-1 also scored significantly lower on the sensory organisation test composite score (69.0[22.3] vs. 79.0[10.5]) and higher on the visual acuity (-0.03[0.33] vs. -0.14[0.12]) and dynamic visual acuity (0.38[0.84] vs. 0.20[0.20]) tests. The importance of caloric, SOT and DVA, was supported by the PCA outcomes. Group-1 tended to report headaches, blurred vision and balance problems more frequently than group-2 (>10% difference).

CONCLUSION

The SOM divided the data into one group with prominent vestibular disorders and another with no clear vestibular or balance problems, suggesting that artificial intelligence might help improve the diagnostic process.

Instrumental head impulse test changes after intratympanic gentamicin for unilateral definite Ménière's disease: A systematic review and meta-analysis

OBJECTIVE

To estimate how much could intratympanic gentamicin (ITG) interfere with the vestibular-ocular reflex (VOR) parameters on instrumental head impulse test (HIT), either with scleral search coil or video head impulse test and, eventually, foresee the control of vertigo crisis in unilateral intractable Ménière's disease (MD).

METHODS

A literature search was conducted in PubMed, Scopus, Web of Science and Cochrane search engines. The search terms used were "vestibular ocular reflex", "head impulse test", "gentamicin," and "Meniere's disease". Limitations included text availability to be full text, species to be humans and language to be English. All study types were included. 89 articles were screened identifying four eligible studies were identified. Studies were included after consensus of the authors. Meta-analysis was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data was analysed using Review Manager software.

RESULTS

Instrumental HIT, after ITG for MD, demonstrated, in the treated ear, a decreased gain in the horizontal, posterior and superior semicircular canals (SCC), of 0.36 (0.26; 0.47; 95% CI), 0.35 (0.22; 0.48; 95% CI) and 0.28 (0.21; 0.35; 95% CI), respectively. Gain asymmetry increases between the treated and non-treated ear of 23.78 (7.22; 40.35; 95% CI), 32.01 (12.27; 51.76; 95% CI) and 17.49 (9.99; 24.99; 95% CI), were similarly detected in the horizontal, posterior and superior SCC, respectively. Significantly smaller gain values after the first treatment were observed for a single injection group versus multiple injection group in the horizontal (p=0.002) and superior SCCs (p=0.016).

CONCLUSIONS

Instrumental HIT is effective in evaluating the SCC function after ITG for intractable unilateral MD. VOR gain changes in the direction of the treated ear in the three SCC have been clearly registered. An increased reduction of the VOR gain in the horizontal and anterior SCC also seemed to foresee the control of vertigo crisis. Still, after meta-analysis, the small number of patients' data available did not allow to define a treatment end-point value. This review also indicated that further and better-designed studies are warranted.

Intratympanic Gentamicin for Intractable Ménière's Disease - A Review and Analysis of Audiovestibular Impact

Introduction  Intratympanic gentamicin regulates the symptoms in most patients with incapacitating Ménière's disease. The treatment protocols have changed over the years from medical labyrinthectomy to preservation of vestibular function.

Objectives  This study aims to review the audiovestibular response related to the effect of the drug in controlling vertigo.

Data Synthesis  Articles were identified by means of a search in the PubMed database using the key words Meniere and intratympanic or transtympanic gentamicin . Total 144 articles were reviewed after excluding those that were technical reports, those based on experimental animal studies, those that focused on outcomes other than vertigo (tinnitus or aural fullness), those with delivery methods other than tympanic membrane injection, and those with bilateral cases. If there was more than one article by the same author(s) or institution, only the most recent one matching the aforementioned criteria and those that were not overlapping were included.

Conclusion  Titration methods or multiple injections on a daily basis can be preferred if the patients have profound or non-serviceable hearing, since these methods have significant incidence of hearing loss. Treatment protocols with a frequency of injection not shorter than once a week, or those with injections on a monthly basis as “needed” provide the same level of vertigo control with better preservation of hearing. Caloric testing is not an ideal tool to analyze the correlation between vertigo control and the effect of gentamicin as compared with gain asymmetry of the vestibulo-ocular reflex. Vestibular-evoked myogenic potentials and the head thrust test are more reliable than other vestibular tests for the follow-up of patients undergoing gentamicin treatment.

Intratympanic dexamethasone injections for refractory Meniere' s disease

Intratympanic injections or titration is a potential medical therapeutic strategy for patients with incurable inner ear diseases. Dexamethasone represent an attractive steroid source in intratympanic steroids strategies in the treatment of inner ear disorders. Here, we evaluated the effectiveness of intratympanic dexamethasone injections (IDI) in outpatients with refractory Meniere's disease (MD). Vestibular function measured by Vestibular Ocular Reflex (VOR) gain and caloric test revealed that 21 outpatients out of 43 (48.8%) had complete sufficient vertigo control, while 9 (20.9%) of them were attached to fundamental manipulation. Out of the 13 remaining outpatients, 4 (9.3%) had a limit control and 9 had less modification. Therefore, 5 of 9 received re-treatment with IDI and 2 of 9 patients were administered ablative treatment with gentamicin. Meanwhile, audiology data suggested that 3 (7.0%), 4 (9.3%), 32 (74.4%), 4 (9.3%) patients were attached to the level of A, B, C, D, respectively. Furthermore, the symptom of tinnitus in 5 outpatients vanished, 21 (48.8%) diminished, 10 (23.3%) invariable, 7 (16.3%) aggravated. In 4 of 24 cases (16.7%), aural fullness disappeared after IDI, when the aural fullness was alleviated in 11 cases (45.8%) even intensive in 9 patients (37.5%). Together, our results demonstrate that intratympanic dexamethasone injection, as an effective therapeutic strategy for refractory Meniere's disease, could either be used for cascade therapy preoperation or used for patients who couldn't accept the surgery.

Single intratympanic gentamicin injection in Ménière's disease: VOR change and prognostic usefulness

OBJECTIVE

Assess angular vestibular-ocular reflex (VOR) changes after treatment with intratympanic gentamicin (ITG) for Ménière's disease (MD) and impact on short-term follow-up.

DESIGN

Prospective study.

METHODS

Patients submitted to ITG for unilateral MD. The gain VOR and the presence of compensatory saccades elicited by rapid head impulses were measured using the video head impulse test (vHIT).

RESULTS

The study included 31 subjects (mean age: 59 years). Functional Level Scale (FLS) distributions were 35,5% (FLS3); 32,2% (FLS4); and 32,2% (FLS5). Mean follow-up was 21 ± 7 months. Multiple injections were needed in nine patients. VOR gain in the treated ear was significantly reduced in all subjects and for all the semicircular canals (paired samples t test; P < 0,05). Gain averages after treatment were 0,61 (superior); 0,69 (horizontal); and 0,47 (posterior). A horizontal canal VOR gain superior to 0,80 after treatment was associated with the need for a second gentamicin injection (Chi-square; P = 0,003). Gain asymmetry between the symptomatic and asymptomatic ear (GASM) was increased after treatment. The rate of vestibular function reduction was 47,9%; 26,0%; and 35,8% for the superior, horizontal, and posterior canals, respectively. According to the receiving operator characteristic curve, the amount of change in GASM must be greater than 7 in order to predict the avoidance of a second procedure (area under the curve [AUC] horizontal canal = 0,861) and the amount of vestibular function reduction in the pathologic ear in patients with a controlled disease must be greater than 17,8% (AUC horizontal canal = 0,843).

CONCLUSIONS

When evaluated with the vHIT, intratympanic gentamicin changes in VOR seem to foresee short-term control of vertigo attacks.

LEVEL OF EVIDENCE

4.

Cochlear function in Ménière's disease

OBJECTIVE

The authors assessed the effectiveness of therapy, common features of pure-tone audiograms, and results of non-invasive electrocochleography before and after mild inhibition of peripheral vestibular function by infrequent administration of single intratympanic gentamicin injections (ITPG) in patients with Ménière's disease (MD).

STUDY SAMPLE

Sixty-two patients with Ménière's disease.

DESIGN

Retrospective study.

RESULTS

Out of 62 patients 65% received one injection, 24% two, 6% three, 3% five, and 2% six injections. Between injections, class A vertigo control was obtained after two weeks in all cases. Before ITPG, out of 62 pure-tone threshold audiograms 37 were 'flat'. Average hearing threshold at 2 kHz was significantly better than that of 250, 500, and 0.75 kHz on the affected side.

CONCLUSIONS

Hearing threshold in advanced MD is often flat with a characteristic small peak in the high frequency range, most frequently around 2-3 kHz. Should the complaints be intolerable, single injection ITPG-therapy may be safe and effective.

Physiologic effects on the vestibular system in Meniere's disease

Ménière syndrome is an inner ear disorder characterized by spontaneous attacks of vertigo, fluctuating low-frequency sensorineural hearing loss, aural fullness and tinnitus. When the syndrome is idiopathic and cannot be attributed to any other cause (eg, syphilis, immune-mediated inner ear disease, surgical trauma), it is referred to as Ménière disease. This article reviews the physiologic effects of Ménière disease on vestibular function, as measured by caloric, head impulse, and vestibular-evoked myogenic potential testing.

Vestibular function and vertigo control after intratympanic gentamicin for Ménière's disease

The aim of this study was to correlate long-term vertigo control with reduction in vestibular function after intratympanic (IT) gentamicin therapy for unilateral Ménière's disease. IT gentamicin injections were given as needed to control vertigo attacks. Vertigo frequency and changes in angular vestibulo-ocular reflex (AVOR) gain (measured using magnetic search coils and manual head thrusts) and caloric weakness were assessed before and after treatment. Better vertigo control after treatment was found with >or=60% reduction in quantitative ipsilateral horizontal semicircular canal AVOR gain from pre-treatment values and/or with caloric unilateral weakness (UW) >50%. However, no correlations were found between the continuous variables of vertigo control and either gain or gain recovery, nor between gain and UW because of the large variability in vertigo control in subjects with lesser reductions in these measures.

Challenge-oriented gait and balance training in sporadic olivopontocerebellar atrophy: a case study

BACKGROUND AND PURPOSE

Sporadic olivopontocerebellar atrophy (OPCA) is a rare and debilitating neurologic disease of insidious onset. It is characterized by atrophy of the cerebellum, pons, and inferior olivary nuclei with concomitant ambulation deficits and dyscoordination. To our knowledge, there has been no published study investigating any aspect of rehabilitation in OPCA. Therefore, the purpose of this study was to investigate the use of challenge-oriented gait and balance training to improve gait and balance in OPCA.

CASE DESCRIPTION

An otherwise healthy 19-year-old woman with moderate to severe upper and lower extremity ataxia, secondary to sporadic OPCA, participated in this prospective case study. She also had a vestibulotoxic treatment procedure to decrease the severity of her vertigo.

INTERVENTION

This individual participated in a 12-week gait and balance training program (five times per week), which consisted of one to two hours of various challenging static and dynamic balance tasks. To measure her progress, the following scales and tests were used: Berg Balance Scale, Dynamic Gait Index, Activities-Specific Balance Confidence Scale, computerized dynamic posturography (sensory organization test and limits of stability), and self-selected gait velocity.

OUTCOMES

: Improvements were noted in all the dependent measures (pre to post): Berg Balance Scale (34/56 to 39/56), Dynamic Gait Index (1/24 to 7/24), Activities-Specific Balance Confidence Scale (50.6%-85.1%), sensory organization test (composite score, 31/100 to 47/100), limits of stability (maximum excursion, 89-105; endpoint excursion, 57-93; directional control, 60-78), and SSGV (0.375-0.526 m/sec).

DISCUSSION

Results from this case study suggest that a gait and balance training program may be beneficial to individuals with ataxia from OPCA. This early evidence warrants further investigation using more rigorous methods.

Middle ear exploration in patients with Ménière's disease who have failed outpatient intratympanic gentamicin therapy

OBJECTIVE

Treatment of medically refractory Ménière's disease (MD) with intratympanic (IT) gentamicin has now become a standard therapy. This procedure is effective in controlling vertigo attacks, but approximately 10% of patients do not have an adequate response. The objective of the current study was to evaluate the option of middle ear exploration with direct application of gentamicin to the round window (MEE-G) in patients with persistent MD after transtympanic injection of gentamicin.

STUDY DESIGN

A retrospective chart review of 191 patients with MD treated with IT gentamicin revealed 16 who failed to have symptomatic relief after transtympanic injection. Options discussed with these patients included labyrinthectomy, vestibular nerve section, and MEE-G.

SETTING

Tertiary referral center.

PATIENTS

Eight patients opted for MEE-G.

INTERVENTION

Patients were taken to the operating room for MEE-G. After removal of the round window obstruction, gentamicin-soaked pledgets were placed for at least 30 minutes.

MAIN OUTCOME MEASURES

Control of MD-related vertigo and need for additional therapy.

RESULTS

At the time of MEE-G, all 8 patients were found to have adhesions, bone dust blocking the round window, or a thickened round window membrane. In 6 of these patients, vertigo symptoms due to MD either resolved with no further therapy (4 patients) or with subsequent IT gentamicin injections in clinic (2 patients). The remaining 2 patients underwent a vestibular nerve section, which resolved MD symptoms in each case.

CONCLUSION

Anatomic barriers to the round window membrane may be a significant cause of IT gentamicin failure, and MEE-G can be considered before ablative therapy in this subset of patients with Ménière's disease.

Time course of repeated intratympanic gentamicin for Ménière's disease

OBJECTIVES/HYPOTHESIS

With low-dose and titration protocols, subsequent intratympanic (IT) gentamicin injections are frequently necessary for vertigo control in Ménière's disease. To date, studies have not provided detailed descriptions of the time course of recurrent vertigo and repeated injections. Our objective is to provide such a description with a Kaplan-Meier survival analysis, which may enable accurate predictions of the probability of recurrent vertigo after a given time or number of injections.

STUDY DESIGN

Injections of IT gentamicin were administered for unilateral definite Ménière's disease. One injection (or rarely more) in a 6-week period constituted a "round." Repeat rounds were given when needed for control of recurrent vertigo.

METHODS

We used a Kaplan-Meier method to quantify percentages of patients with control of vertigo over an 8-year period. A separate curve was created for each number of rounds, and failure for each was defined as the need for an additional round.

RESULTS

Of 78 patients, 75 (96%) achieved sufficient vertigo control to avoid ablative surgery, and 42 (54%) required only one round. Thirty-six (46%) required multiple rounds. The probability of needing another round increased with each subsequent one, through four rounds. The median times to the next round after one, two, or three rounds were 148, 118, and 124 days, respectively.

CONCLUSIONS

More than half of patients need only one round of IT gentamicin injections. With each additional round through the fourth one, the probability of additional rounds increases. Nevertheless, the majority (96%) of patients do not need ablative surgery after IT gentamicin.

[Multifrequency vestibular study after vestibular neurotomy and chemical labyrinthectomy]

OBJECTIVES

Vestibular neurotomy (VN) and chemical labyrinthectomy (CL) are the two most common techniques of vestibular deafferention to treat patients with intractable vertigo. A long-term evaluation of vestibular function has been performed with a variety of vestibular tests to find out whether there persisted any residual vestibular function after each technique.

METHODS

We called in all patients who have been treated for the last 10 years and have no known vestibular disease in the non treated ear. Low frequencies were analyzed with caloric tests, medium frequencies with the head-shaking test and head-impulse test, and high frequencies with the skull vibration test. The otolithic function was explored with the subjective vertical visual analysis and otolithic myogenic evoked potentials. Nine patients treated with VN and 12 with CL presented to our department. We were thus able to compare VN and CL patients with a group of 10 normal patients and another group of nine patients that had had a translabyrinthine approach for an acoustic neuroma.

RESULTS

We found out that vestibular responses did persist in seven out of nine (78 %) patients after VN and 11 out of 12 (92 %) patients after CL. On the other hand, no vestibular response was detected following resection of vestibular schwannoma through a translabyrinthine approach.

CONCLUSION

We came to the conclusion that the two latter techniques, unlike vestibulocochlear nerve section via the translabyrinthine approach, are only incomplete methods of vestibular deafferention.

Longitudinal results with intratympanic dexamethasone in the treatment of Ménière's disease

OBJECTIVE

To assess patient satisfaction with vertigo control using intratympanic (IT) dexamethasone (12 mg/mL) for medically refractory unilateral Ménière's disease.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary referral neurotology clinic.

PATIENTS

One hundred twenty-nine subjects diagnosed with unilateral Ménière's disease still having vertigo despite medical therapy.

INTERVENTION

IT dexamethasone injections as needed to control vertigo attacks.

MAIN OUTCOME MEASURE

A Kaplan-Meier time-to-event method was used to determine the rate of "survival," meaning sufficient satisfaction with vertigo control that the subject did not wish to have subsequent ablative treatment. "Failure" was defined as poor control and the choice to proceed to ablative treatment.

RESULTS

Acceptable vertigo control ("survival") was achieved in 117 (91%) of 129 subjects. Vertigo control required only one dexamethasone injection in 48 (37%), 2 injections in 26 (20%), 3 injections in 18 (14%), and 4 injections in 10 (8%). More than 4 injections were needed in 15 subjects (21%). Of 12 failures (9%), 9 occurred within 6 months of the first IT dexamethasone injection. Follow-up data for 2 years were available for 96 subjects. Of these, 87 (91%) had vertigo control with IT dexamethasone, of whom 61 (70)% required no further injections after 2 years, 23 (26%) continued to receive IT dexamethasone injections, and 3 (3%) chose IT gentamicin treatment.

CONCLUSION

IT dexamethasone injection therapy on an as-needed outpatient basis can provide vertigo control that is satisfactory in patients with Ménière's disease. The Kaplan-Meier method addresses the need for an outcome measure suited to repeated treatments and variable lengths of follow-up. However, due to the retrospective nature of this study, the presence of bias caused by loss of subjects from follow-up cannot be ruled out.

Implication of vibration induced nystagmus in Meniere's disease

CONCLUSION

The incidence of ipsilesional beating vibration induced nystagmus (VIN) is significantly higher in Meniere's disease (MD) with lower canal paresis (CP) group on caloric test and the intensity of VIN shows significant positive correlation with CP. Considering previous reports showing predominant loss of type II hair cells in MD and discrepancy of the results between caloric test and head thrust test in MD patients, VIN may provide valuable information regarding the functional reservoir of vestibular type II hair cells in MD.

OBJECTIVES

Clinical presentation of MD is dynamic and nystagmus changes phase to phase, which is attributed to the recovery process in addition to central compensation after active vertigo attack of MD. VIN has been shown to reflect the side difference of peripheral vestibular excitability and is well correlated with the severity of caloric weakness in vestibular neuritis. Aim of this study was to compare the intensity and the direction of VIN with CP in unilateral MD.

MATERIALS AND METHODS

52 patients with unilateral definite MD on AAO-HNS guideline (1995) were included. Auditory and vestibular function tests including caloric test, post-head shaking nystagmus (HSN) and VIN were evaluated during symptom free period and cases with spontaneous nystagmus were excluded. Vibratory stimuli (100 Hz) were applied to either mastoid alternatively. Eye movement was recorded using video nystagmography system. The horizontal component of VIN was compared with HSN and caloric test.

RESULTS

37 patients (71%) showed VIN. VIN to ipsilesional side was in 10 and to contralesional side in 27. In patients with CP over 43% (N =23), 2 beated to ipsilesional side, 17 to contralesional side and 4 showed no VIN. In patients with CP of less than 43% (N =29), 8 beated to ipsilesional side, 10 to contralesional side and 11 showed no VIN (p<0.05). 33 patients (63%) showed HSN and 24 patients of them (72%) showed contralesional nystagmus. The intensity of VIN shows significant positive correlation with the degree of CP on caloric test (Spearman's rho =0.340, p<0.05).

[Vestibulo-oculomotor reflex recording using the scleral search coil technique. Review of peripheral vestibular disorders]

Our goal is to review vestibulo-oculomotor reflex (VOR) studies on several peripheral vestibular disorders (Ménière's disease, vestibular neuritis, benign paroxysmal positional vertigo, superior canal dehiscence syndrome, and vestibular neuroma), using the scleral search coil (SSC) technique. Head movements are detected by vestibular receptors and the elicited VOR is responsible for compensatory 3 dimensional eye movements. Therefore, to study the VOR it is necessary to assess the direction and velocity of 3 dimensional head and eye movements. This can be achieved using the SCC technique. Interaction between a scleral search coil and an alternating magnetic field generates an electrical signal that is proportional to eye position. Ideally, eye rotation axis is aligned with head rotation axis and VOR gain (eye velocity/head velocity) for horizontal and vertical head rotations is almost 1. The VOR gain, however, for torsional head rotations is smaller and about 0.7.

Delivery of drugs to the inner ear

PURPOSE OF REVIEW

Inner ear delivery of medicines has been a rapidly expanding field in otolaryngology. This technique provides a minimally invasive way of managing a number of otolaryngologic diagnoses and promises to provide a therapeutic option for previously untreatable disorders. The purpose of this review is to examine the literature that has been published recently (since January of 2005) in this field and to explore how this new literature has impacted on current practices.

RECENT FINDINGS

While there was a significant volume of work done in this area from 1995 to 2004, publication in this area has slowed considerably. The literature focuses on two areas: the treatment of Ménière's disease with gentamicin and the treatment of sudden sensorineural hearing loss with steroids. The most promising area in this field, which is the development of new medicines to treat a variety of disorders, has not progressed over the last 2 years.

SUMMARY

Recent peer-reviewed publications have not had a significant impact on the transtympanic treatment of Ménière's disease or sudden sensorineural hearing loss. We will review the current practices in these two areas, discuss the newest developments and examine how we can progress the field over the next several years.