The Clinical Benefit of Device Therapy for Meniere's Disease in Adults: Systematic Review and Meta-Analysis.

OBJECTIVES: This study aimed to assess the clinical benefit of device therapy on controlling the symptoms of Meniere's disease (MD). MATERIALS AND METHODS: We searched PubMed, Embase, the Cochrane Library, China National Knowledge Internet, and Wanfang Data before January 13, 2018. We selected randomized controlled clinical trials, case-controlled studies, and cohort studies that dealt with outcomes of device therapy for the treatment of MD. RESULTS: Sixteen trials met our inclusion criteria. The use of device therapy resulted in improved vertigo control, which was described as a reduction in the number of vertigo days by month (weighted mean difference [WMD]: 3.15, 95% confidence interval [CI]: 2.00-4.31), in the number of vertigo episodes by month (WMD: 7.37, 95% CI: 2.40-12.35), and in the vertigo visual analog score (WMD: 41.51, 95% CI: 34.68-48.34). In addition, the overall complete vertigo control (class A) rate was 50% (95% CI: 37%-64%). The device therapy also reduced the number of sick days by month (WMD: 4.56, 95% CI: 2.15-6.97), and the functional level improved (WMD: 2.66, 95% CI: 2.15-3.17). The electrocochleographic parameters decreased. The device therapy proved beneficial for hearing changes (WMD: 3.19, 95% CI: 0.66-5.71). No publication bias was found in the funnel plot and the results of Egger's test. CONCLUSION: This study showed that the device therapy might reduce vertigo attacks and sick days in patients with MD. Additionally, the function level and hearing level may improve after the device therapy. In addition, the decrease in electrocochleographic parameters showed that inner ear electrophysiology improved after device therapy.

Search for normality criteria of auditory brain responses and auditory steady state response with free-field stimulation. / Búsqueda de criterios de normalidad de potenciales evocados auditivos de tronco cerebral y potenciales evocados auditivos de estado estable con estímulo en campo libre.

OBJECTIVE: To discover the thresholds of normality of the tests of ABR and ASSR in free-field stimulation compared with headphones. METHODS: Descriptive study of a series of cases of children without hearing loss carried out between April 2016 and January 2017. The ABR and conventional ASR were performed using insert headphones and free-field stimulation. RESULTS: Fifty-four ears were evaluated with absolute criteria of normality. The mean age was 16.7 months (SD=5.7). The evocation of the action potential at 70 dBs in the free-field showed a mean on wave I of 3.47ms, on wave II of 4.01, on wave III of 5.97, on wave IV of 6.71 and on wave V of 8.22. There is a statistically significant difference (p<.05) between the value obtained with insert earphones and the free-field on wave I (mean difference 1.91), on wave III (1.88), on wave IV (1.69) and on wave V (1.95), their being higher in stimulus in free field. There were no statistically significant differences in the interlatencies. The responses in the ASSR with free-field showed an increase of 1.56minutes compared to the headphones. CONCLUSIONS: The thresholds obtained in ABR by free-field were differentiated from those obtained by headphones in the increase of latencies, caused by delayed stimulation of the ear due to the distance between the sound source and the eardrum. Both tests are feasible by free-field stimulation, which would allow them to be applied routinely to patients on whom conventional tests cannot be performed.

ABR-based newborn hearing screening with MB11 BERAphone® using an optimized chirp for acoustical stimulation.

OBJECTIVE: At our center, the Maico MB11 BERAphone(®) device is used for newborn hearing screening based on Auditory Brainstem Responses (ABR). In 2006, an optimized chirp stimulus was implemented in the device to increase the reliability and quality of the screening method. In 2002, an automated response detection algorithm had been implemented. This study analyzes the screening results using the MB11 BERAphone(®) device with the implemented chirp stimulus and automated response detection method. METHODS: The data presented were collected in the well-baby nursery as part of the newborn hearing screening program following a two stage screening protocol. To focus the study on the typical routine screening, data from at-risk babies were not included. Overall, data from 6866 babies (3604 males and 3262 females) screened from March 2006 to April 2011 were analyzed in this study. RESULTS: Out of the 6866 babies screened, 6607 passed bilaterally prior to hospital discharge (defined as 1st stage in this hearing screening program). Therefore, the pre-discharge pass rate of the hearing screening with the MB11 BERAphone(®) device was 96.2%. The resulting referral rate was 3.8%. The median test time per ear (excluding time for preparation and data reporting) was 28s with a range of 15-112s (5-95th percentile). The number of infants referred for 2nd stage, post-discharge re-screening was 259. Of this group, 71 passed bilaterally and 188 failed the re-screening in one or both ears. Therefore, including both the pre-discharge and post-discharge screening results, the bilateral pass rate was 97.3% and 2.7% were referred for diagnostic evaluation. Diagnostic testing was performed on all of the 188 infants who were referred. Results showed that 47 of these babies had hearing loss. This equates to a positive predictive value for a refer result of 25%. The observed prevalence of hearing impairment in our population was 0.684%. Diagnostic results for 141 of the referred newborns proved that they had normal hearing. That is, 141 out of 6866 newborns had a false-positive result with the MB11 BERAphone(®) screening. Therefore, the device had a specificity of 97.9%. During the time period of this study, no baby who passed the hearing screening was later found to have hearing impairment, suggesting a sensitivity of 100%. However, due to the limited number of newborns and the short time period after screening for the more recently screened babies, a reliable estimate of the sensitivity cannot be yet made from our program statistics. The theoretical sensitivity of the MB 11 device is 99.9%. CONCLUSIONS: The Maico MB11 BERAphone(®) is a reliable device for auditory brainstem response newborn hearing screening and it provides results within a very short time. Due to the implemented method for automatic detection of ABR, the use of the device does not require an experienced examiner, allowing it to be used by trained technicians in locations outside the department of audiology such as the well-baby nursery.

Click- and chirp-evoked human compound action potentials.

In the experiments reported here, the amplitude and the latency of human compound action potentials (CAPs) evoked from a chirp stimulus are compared to those evoked from a traditional click stimulus. The chirp stimulus was created with a frequency sweep to compensate for basilar membrane traveling wave delay using the O-Chirp equations from Fobel and Dau [(2004). J. Acoust. Soc. Am. 116, 2213-2222] derived from otoacoustic emission data. Human cochlear traveling wave delay estimates were obtained from derived compound band action potentials provided by Eggermont [(1979). J. Acoust. Soc. Am. 65, 463-470]. CAPs were recorded from an electrode placed on the tympanic membrane (TM), and the acoustic signals were monitored with a probe tube microphone attached to the TM electrode. Results showed that the amplitude and latency of chirp-evoked N1 of the CAP differed from click-evoked CAPs in several regards. For the chirp-evoked CAP, the N1 amplitude was significantly larger than the click-evoked N1s. The latency-intensity function was significantly shallower for chirp-evoked CAPs as compared to click-evoked CAPs. This suggests that auditory nerve fibers respond with more unison to a chirp stimulus than to a click stimulus.

Using concha electrodes to measure cochlear microphonic waveforms and auditory brainstem responses.

During electrocochleography, that is, ECochG or ECoG, a recording electrode can be placed in the ear canal lateral to the tympanic membrane. We designed a concha electrode to record both sinusoidal waveforms of cochlear microphonics (CMs) and auditory brainstem responses (ABRs). The amplitudes of CM waveforms and Wave I or compound action potentials (CAPs) recorded at the concha were greater than those recorded at the mastoid but slightly lower than those recorded at the ear canal. Wave V amplitudes recorded at the concha were greater than those recorded at the ear canal but lower than those recorded at the mastoid. There was not a significant difference between the amplitudes recorded at the concha and at the ear canal. For CM and Wave I or CAP, the latency recorded at the concha was longer than at the canal but shorter than at the mastoid; for Wave V, the reverse was true. However, these differences were not statistically significant and may be due to the distance to response generators. Aside from the advantages that the regular ECoG has over otoacoustic emission (OAE) testing, the concha electrode was also easier and safer to place and may be suitable for children, newborn screening, participants with canal conditions, and remote clinics which could have concerns with the availability and cost of a canal electrode. Using concha electrodes, we also experienced fewer postauricular artifacts than when using a mastoid electrode.

A flexible research platform for multi-channel auditory steady-state response measurements.

The possibilities of currently commercially available auditory steady-state response (ASSR) devices are mostly limited to avoid unintentional misuse and to guarantuee patient safety as such. Some setups, e.g. do not allow the application of high intensities or the use of own stimuli. Moreover, most devices generally only allow data collection using maximal two EEG channels. The freedom to modify and extend the accompagnying software and hardware is very restricted or inexistent. As a result, these devices are not suited for research and several clinically diagnostic purposes. In this paper, a research platform for multi-channel ASSR measurements is presented, referred to as SOMA (setup ORL for multi-channel ASSR). The setup allows multi-channel measurements and the use of own stimuli. It can be easily extended to facilitate new measurement protocols and real-time signal processing. The mobile setup is based on an inexpensive multi-channel RME soundcard and software is written in C++. Both hardware and software of the setup are described. An evaluation study with nine normal-hearing subjects shows no significant performance differences between a reference and the proposed platform. SOMA presents a flexible and modularly extensible mobile high-end multi-channel ASSR test platform.

Methodology to estimate the transient evoked responses for the generation of steady state responses.

A method to acquire transient evoked responses at high rates, corresponding to traditional steady state responses (SSR) is developed. Continuous Loop Averaging Deconvolution (CLAD) method is used in conjunction with tailored, low-jitter stimulation sequences. A physiological brain convolution model for SSR generation is adapted and mathematically analyzed. A SSR synthesis method from acquired transient evoked potentials is proposed and implemented. The mathematical models are used to guide the stimulation sequence design method. Visual evoked potentials (VEP) at 10 Hz and auditory evoked responses (AER) at 40 Hz and 80 Hz are acquired using the specially designed and the traditional SSR sequences. Acquired and synthetically generated SSRs are then compared in time and frequency domains to asses the method consistency. The experimental results show an excellent agreement between the acquired and synthetic SSR in all three modalities.

A system to generate patient-specific stimuli for use with the auditory brainstem response test.

The short-pulsed "click" stimuli most commonly used to evoke an Auditory Brainstem Response (ABR) do not account for temporal shifts along the basilar membrane and do not produce ABRs of maximal amplitude. This paper describes a system that maps these temporal shifts and generates patient-specific stimuli to compensate. This is of interest both to enhance the ABR and as a potential way to map the physiology of the basilar membrane.

Call for calibration standard for newborn screening using auditory brainstem responses.

The mode of stimulation employed in newborn screening of the auditory brainstem response has evolved from the clinically standardized supraaural earphone to the tubal insert earphone, to most recently a circumaural earphone developed for this test. Considered here is the need to develop a standard for calibration of such devices for newborn screening applications, in particular. At risk is the prospect of missing the milder degrees of hearing loss, assuming a goal of detecting all clinically-significant congenital hearing losses. Two commercially manufactured test instruments for automated newborn screening were scrutinized via bench testing of sound output from their respective transducers, using a variety of measurements. By convention or design, none of the measurement approaches involved a model of the newborn ear, per se. While it was concluded that the manufacturers' method shows promise, namely as a relatively simple and potentially reliable method of calibration, concerns arose regarding output levels when measured according to both the manufacturers' and the authors' methods. Further work is needed to critically assess calibration methods and to establish, to the extent possible, appropriate norms and validation studies in newborns to provide a better understanding of the actual sound pressure level of the screening stimulus.

Meta-analysis of variables that affect accuracy of threshold estimation via measurement of the auditory steady-state response (ASSR).

Reported are the results of meta-analyses of data derived collectively from a sample of 56 published research studies on electric response audiometry (ERA) using auditory steady-state responses (ASSRs). Several specific methodological issues were examined and hypotheses were posited to rigorously test common conclusions drawn from the ASSR literature on the accuracy of ASSR-ERA. Explanatory variables for analyses were type of population (normally hearing and hearing-impaired), type of modulation, number of sweeps acquired during response analysis, electrode montage, and modulation rate (80 vs. 40 Hz). No explanatory variables were found to be significantly related to the degree of disparity between thresholds obtained by ASSR-ERA versus behavioral audiometry in the normally hearing population. Conversely, all but one explanatory variable (i.e. electrode montage) was found to be significantly related to mean threshold differences in the hearing-impaired and combined populations. Results both substantiate some of common conclusions drawn from the literature but call others into question, helping to identify those methodological issues which appear to, or not to, significantly affect the accuracy of estimating threshold using ASSR measurement. In addition to these findings, another practical outcome of this study was the development of various summary tables of the data analysed from the literature sampled.

Acquisition and analysis of high rate deconvolved auditory evoked potentials during sleep.

Auditory Evoked Potentials (AEPs) have been recorded at high stimulus rates during sleep using Continuous Loop Averaging Deconvolution (CLAD) sequences. AEP transient signals are obtained via frequency domain deconvolution of overlapped responses. Simultaneous acquisition of Auditory Brainstem Response (ABR), Middle Latency Response (MLR), and Long Latency Response (LLR) is obtained at an average stimulation rate of 39.1 Hz, using 10, 20 and 100 second electroencephalography (EEG) recordings. Deconvolved responses confirm previous observations on the reduction and disappearance of the P1 MLR component during stage III and IV, obtained with standard averaging and stimulation methods. Results indicate that auditory stimulation at high rates during sleep, using short time sweeps, may help correlating the sleep EEG indicative of different arousal levels, with corresponding AEPs.

Deconvolution of evoked responses obtained at high stimulus rates.

Continuous loop averaging deconvolution (CLAD) is a new general mathematical theory and method developed to deconvolve overlapping auditory evoked responses obtained at high stimulation rates. Using CLAD, arbitrary stimulus sequences are generated and averaged responses deconvolved. Until now, only a few special stimulus series such as maximum length sequences (MLS) and Legendre sequences (LGS) were capable of performing this task. A CLAD computer algorithm is developed and implemented in an evoked potential averaging system. Computer simulations are used to verify the theory and methodology. Auditory brainstem responses (ABR) and middle latency responses (MLR) are acquired from subjects with normal hearing at high stimulation rates to validate and show the feasibility of the CLAD technique.

[Auditory brainstem responses evoked by direct mechanical stimulation of the ossicular chain. Objective preoperative testing of candidates for implantable hearing aids]. / Frühe akustisch evozierte Potenziale bei direkter mechanischer Stimulation der Gehörknöchelchenkette. Objektive Eignungsdiagnostik vor Implantation von Hörsystemen.

BACKGROUND AND OBJECTIVE: The function of several implantable hearing systems is based on the vibratory excitation of the ossicular chain. For preoperative testing, malleus vibration audiometry has been described [7]. In special cases, it could be desirable to perform objective testing before implantation. We therefore studied the auditory brainstem responses (ABR) evoked by vibratory stimulation of the ear drum. METHOD: The ABR evoked by vibratory and acoustical click stimulation were recorded in 20 subjects with normal hearing at four different stimulus intensities. For the vibratory stimulation (v-ABR), the transducer rod was brought into mechanical contact with the eardrum under microscopic control. This setup was further used for the determination of the individual subjective threshold. The v-ABR were compared to conventional ABR recordings. RESULTS: In all subjects, the v-ABR could clearly be identified. At high stimulus levels, the complete wave pattern was observed in 15 of 20 cases. There is no essential difference between v-ABR and conventional ABR with respect to the incidence and parameters of the potentials. At high stimulus levels, a pronounced stimulus artefact impedes the identification of wave I in some cases. Moreover, the quality of v-ABR is limited by the uncomfortable situation and incomplete relaxation of the subject. CONCLUSIONS: The measurement of vibratory evoked ABR is practicable without hazards for the patient and it yields reliable results. The hearing threshold for click stimuli can be determined from the incidence and amplitude of the responses. The loudness associated with the click stimuli can be estimated from the response latency. Therefore, the investigation of v-ABR not only gives evidence of the individual suitability for implantable hearing aids but its outcome may also be useful as an orientation for the postoperative fitting.

The effects of high stimulus rate on the electrocochleogram in normal-hearing subjects.

The use of high stimulus rates has the potential to improve the electrocochleogram's (ECochG) sensitivity and specificity in endolymphatic hydrops and Menière's disease, but is currently hindered by the absence of an acceptable normative database. In response, this study recorded click-evoked ECochG tracings from 51 normal-hearing subjects (102 ears), between 18 and 60 years of age, at 7.1, 51.1, 101.1 and 151.1 clicks/s using a tympanic membrane electrode. As stimulus rate increased, various statistically significant (p < 0.05) changes were observed. In general, summating potential (SP) latency and amplitude and action potential (AP) latency increased, SP/AP amplitude ratio and waveform width increased but then plateaued, and AP amplitude fluctuated. While providing the largest contribution to a high-stimulus-rate ECochG normative database published to date, potential clinical limitations were identified and a possible solution proposed.

A comparison of the three-dimensional auditory brainstem response and the conventional auditory brainstem response in children.

For measurement of neural activity in the brainstem auditory pathway, the conventional two-dimensional (2D) auditory brainstem response (ABR) does not provide a true response, because the equivalent dipoles originate from the stereoregularity pathway. It is thus necessary to use three-dimensional (3D) ABR to estimate the true response of the brainstem. We recorded 3D ABR in a group of children and adults, and compared the results with those of the conventional 2D ABR. The subjects were 22 children (age range 3-10 years) and 10 adults with no neurological disorders, and three patients: a boy and a girl who had experienced sudden brainstem dysfunction, and a girl who had sudden deafness. 3D ABR was recorded for all subjects, and the results were displayed on a computer screen for off-line analysis using an original 3D ABR analysis program. Four leaf-like vector segments of 3D ABR existed during the first 8 ms after stimulation. Each vector segment corresponded to a peak of the conventional ABR, and showed the original directivity. The amplitudes of waves II and IV of the 3D ABR were significantly larger than those of the conventional ABR. 3D ABR was shown to be superior to the conventional ABR in obtaining absolute amplitude. We were able to clarify the development of brainstem function using 3D ABR. In one patient in whom only one wave was obtained, 3D ABR was able to identify the wave as wave V. These results indicate that ABR is useful both for identifying the kind of wave produced and for suggesting the wave origin.

A novel real-time noise reduction system for the assessment of evoked otoacoustic emissions.

A novel noise reduction method and apparatus to be used in connection with the measurement of evoked otoacoustic emissions (EOAE) are presented. The noise reduction method is based on an adaptive noise canceller and requires a noise-only reference microphone placed in the vicinity of the OAE-probe. The method was implemented in real time on a custom built digital signal processing system using an Analog Devices ADSP-2181 digital signal processor. The system interfaces seamlessly with a commercial EOAE acquisition system. Results of a series of experiments show than noise reductions of 7-8 dB can be reached.

Effective anaesthesia for transtympanic electrocochleography.

The objective of this study was to quantify the anaesthetic effect of EMLA cream during transtympanic electrocochleography (TTECochG) and thereby to determine if the application of EMLA should be recommended in routine practice of electrocochleography (ECochG). ECochG provides useful information in patients with inner ear fluid disorders. A major concern regarding transtympanic positioning of the electrode in ECochG is patient discomfort. Previous work has suggested that EMLA cream may make this technique more tolerable to patients. A prospective randomized study was performed evaluating the discomfort associated with unilateral TTECochG in a group where EMLA cream was used to anaesthesize the tympanic membrane (n = 24), and in a group where no anaesthesia was used (n = 22). A statistically significant difference was evident between the discomfort ratings of the groups (P < 0.0001, Mann-Whitney U test), the discomfort being greater in the no anaesthesia group. EMLA cream has thus been shown to alleviate the level of discomfort associated with TTECochG and so to be an acceptable modification of this technique.

Recording techniques for transtympanic electrocochleography in clinical practice.

Enhancement of the signal-to-noise ratio is a central issue in electrically evoked response techniques. Transtympanic electrocochleography requires careful methodological considerations as responses from the cochlea may easily be affected by various sources of electromagnetic noise. The final electrophysiological waveforms are acquired by advanced signal processing which influences the content of the recordings. A standard method of transtympanic electrocohleography is presented here to increase the feasibility of the measurements in daily clinical use and to facilitate uniform interpretation of the recordings. The electrocochleographic recordings were carried out in 61 patients with a clinical diagnosis of Meniere's disease and in 15 ears of normal hearing subjects. The electrophysiological data are presented and set in relation to the results reported by other laboratories under equivalent recording conditions. Methodological factors of consequence for the quality of the recordings, such as testing environment, properties of the equipment, mode to produce and deliver stimuli and properties of the electrodes, are analysed.

Los generadores de los potenciales aditivos de latencia corta. Revisión de tema / Generators of the short latency brainstem auditory evoked potentials. A review

El estudio de los potenciales auditivos de latencia corta es un indicador diagnóstico ampliamente utilizado en audiología y neurotología. Sin embargo, los generadores de estos potenciales son aún motivo de discusión en numerosos artículos. En la actualidad, se conoce con certeza el generador anatómico de la onda I, producida por la porción distal del nervio coclear. Por otro lado, se ha descrito con seguridad a la porción proximal del mismo nervio como el generador de la onda II. La mayor cantidad de cuestionamientos surgen acerca de la partipación de los núcleos cocleares ipsilaterales en la generación de esta misma. Mas aún, surgen dudas al intentar dar origen al potencial o potenciales postsinápticos que generan las ondas III, IV y V, las cuales se creen son generadas principalmente por los núcleos cocleares ipsilaterales, el complejo olivar superior y el lemnisco lateral contralaterales, respectivamente. Se cree que estas estructuras anatómicas son las mayores contribuyentes de las tres últimas ondas descritas pero son las mayores contribuyentes de las tres ultimas ondas descritas pero no las únicas. El propósito de este trabajo es revisar las aportaciones de diversos artículos que han estudiado específicamente los generadores de los potenciales auditivos de latencia corta

Cochlear microphonics recordable at the non-shielded bedside using a new tubal transducer.

A new tubal transducer (NC-3) for measuring cochlear microphonics (CM) in extratympanic electrocochleography (ECochG) was developed by improving the common hearing aid earphone. Using a human forearm as a dummy ear, the artifact contamination generated from the NC-3 tubal transducer was tested and the possibility of measuring the CM at a non-shielded bedside was studied. An HN-5 electrode was fixed to a subject's forearm, and a sound stimulus of 90 dBnHL was delivered through the tube of the NC-3. When the earphone of the transducer was placed at a right-angle to the electrode on either a vertical or horizontal plane and the electrode was placed in direct contact with the tip of the tube, contamination from electromagnetic induction and CM-like mechanical vibration were prevented. Using the HN-5 electrode and NC-3, extratympanic ECochG-CM was recorded from normal-hearing subjects in both a shielded soundproof room and a non-shielded ordinary, quiet room. No differences were found between CMs measured in the two rooms. These results suggest that the NC-3 overcomes the shortcomings of a loudspeaker system and allows CM to be recorded accurately at non-shielded bedsides.