Melody of Vocants: Fixed Pattern or Shaped by Hearing?

INTRODUCTION: Vocants as infants' first vocalic utterances are produced laryngeally while the vocal tract is maintained in a neutral position. These "primitive" sounds have sometimes been described as largely innate and, therefore, as sounding alike in both healthy and hearing-impaired young infants. OBJECTIVE: The objective of this study is to compare melody features of vocants, recorded during face-to-face interaction, between infants (N = 8) with profound congenital sensorineural hearing loss (HI group) and age-matched (N = 18) controls (CO) group. The question was as follows: does a lack of auditory feedback have a noticeable effect on melodic features of vocants? METHODS: The cooing database totalled 6,998 vocalizations (HI: N = 2,847; CO: N = 4,151), all of which had been recorded during the observation period of 60-181 days of age. Identification of the vocants (N = 1,148) was based on broadband spectrograms (KAY-CSL) and auditory impressions. Fundamental frequency (F0) analyses were performed (PRAAT) and the pattern of the F0 contour (melody) analysed using specific in-lab software (CDAP, pw-project). Generalized mixed linear models were used to perform group comparisons. RESULTS: There was a clear predominance of a simple rising-falling pattern (single melody arcs) in vocants of both groups. Nonetheless, significantly more complex contours, particularly, double-arc structures, were found in vocants of the CO group. Moreover, vocants of the HI group were shorter than those uttered by the CO group, while the mean F0 did not significantly differ. CONCLUSION: Vocants are characterized by both, innate features, found in HI and CO groups, and features that additionally require a functioning auditory system. Even at an early pre-linguistic stage, somatosensory sensations cannot compensate for a lack of auditory feedback. Vocants might be relevant in the early diagnosis of hearing disorders and assessments of the effectiveness of, or adjustments required to, hearing aids.

The Stapes Head Coupler-A Flexible and Safe Option for Vibroplasty.

OBJECTIVE: To investigate the surgical approach and the audiological outcome of a stapes head coupler in active middle ear implant surgery. STUDY DESIGN: Retrospective data analysis. SETTING: Tertiary referral center with a large active middle ear implant program. PATIENTS: Twelve patients with active middle ear implant surgery. INTERVENTIONS: Therapeutic surgical approach for hearing rehabilitation in human subjects. MAIN OUTCOME MEASURES: Auditory brainstem response, sound field thresholds, vibrogram, speech perception in the Freiburger monosyllabic word test. RESULTS: The stapes head was attached safely in different coupling situations. Audiological outcomes were similar to the audiological performance of established vibroplasty couplers presented in the literature. CONCLUSION: The stapes head coupler is a new and safe tool for vibroplasty with a good audiological outcome.

Application of an Intraoperative Auditory Brainstem Response Measurement System in Active Middle Ear Implant Revision Surgery.

OBJECTIVE: To investigate the benefit of intraoperative auditory brainstem response (ABR) measurements in revision active middle ear implant surgery. STUDY DESIGN: Retrospective data analysis. SETTING: Tertiary referral center with a large active middle ear implant program. MAIN OUTCOME MEASURES: Intraoperative ABR thresholds, audiogram, sound field thresholds, speech understanding in the Freiburger monosyllabic word test. PATIENTS: Fourteen patients with active middle ear implant revision surgery. RESULTS: The application of the ABR measurement resulted in improved sound field thresholds and enhanced speech understanding. Analysis revealed a significant correlation of intraoperative gain in ABR threshold with the postoperative gain in sound field thresholds. CONCLUSION: ABR monitoring can be a useful tool to provide information intraoperatively about the coupling efficiency of the FMT. Especially in revision surgeries, this might help to improve postoperative hearing success.

Do cochlear microphonics evoked by narrow-band chirp stimuli affect the objective detection of auditory steady-state responses?

OBJECTIVE: It has recently been discussed whether hearing screening and hearing threshold assessment can accurately be completed using automated ASSR methods for children with auditory neuropathy spectrum disorder (ANSD). Possible causes for the claimed potential failures were investigated here. DESIGN: The study is based on the analysis of stored ASSR raw data. STUDY SAMPLE: This study reviewed raw ASSR data from 274 patients with a total of 5809 individual recordings. RESULTS: Cochlear microphonics (CM) were found in 18 of the 274 patient records. Four of these 18 were obtained from patients with ANSD. One patient with ANSD without click auditory brainstem responses up to 100 dBnHL demonstrated clear ASSR responses from 65 dBnHL upwards. Where click stimulation suggests an auditory nerve defect, narrow-band chirps were shown to evoke ASSR in certain patients. CMs are elicited by narrow-band chirps in the same way as by broadband stimuli. CM residuals as well as a presumed enlarged wave I with absent neural responses, always accompanied by CM, were found as possible causes of misinterpretation at high stimulus levels. A CM detector was created. CONCLUSIONS: The CM detector, indicating the presence of CM, will prevent misinterpretation of clinical ASSR results.

Application of intentional facial nerve stimulation during cochlear implantation as an electrophysiological tool to estimate the intracochlear electrode position.

This proof of concept describes the use of evoked electromyographic (EMG) activation of the facial nerve for intraoperative monitoring of the electrode insertion during cochlear implantation (CI). Intraoperative EMG measurements from the facial nerve were conducted in nine patients undergoing CI implantation. Electric current pulses were emitted from contacts on the CI array during and immediately after electrode insertion. For control, the results of EMG measurements were compared to postoperative flat panel volume computed tomography scans with secondary reconstruction (fpVCTSECO). During insertion, the EMG response evoked by the electrical stimulation from the CI was growing with the stimulating contact approaching the facial nerve and declined with increasing distance. After full insertion, contacts on the apical half of the CI array stimulated higher EMG responses compared with those on the basal half. Comparison with postoperative imaging demonstrated that electrode contacts stimulating high EMG responses had the shortest distances to the facial nerve. It could be demonstrated that electrically evoked EMG activation of the facial nerve can be used to monitor the progress during CI electrode insertion and to control the intracochlear electrode position after full insertion.

Intraoperative Auditory Brainstem Response Measurements via the Vibrant Soundbridge Active Middle Ear Implant: Comparison of Two Methods.

PURPOSE: The Vibrant Soundbridge (VSB) active middle ear implant can be used to treat adults and children with hearing loss. Intraoperative measurements based on auditory brainstem response (ABR) allow the determination of the implant's performance. Two methods for stimulus presentation during ABR measurements via VSB will be compared. METHOD: ABRs were measured in patients implanted with a VSB using a standard ABR system. The stimulus was transmitted directly to the VSB using a new transmission unit (AcoustiAP, MED-EL) and for comparison via a standard audio processor coupled to a wireless streaming device. The study included 10 subjects with mild-to-profound sensorineural, conductive, or mixed hearing loss. RESULTS: As opposed to the wireless method, the AcoustiAP transmits the ABR stimulus without additional signal processing. Therefore, only minor distortions of the transmitted signal are to be expected. There was no significant difference between the performance of the two methods (mean wave V amplitudes 313 [75.2] vs. 301 [88.2] nVpp). In addition, the new system allowed for a more stable connection to the implant system. CONCLUSION: The AcoustiAP is a valuable tool for performing ABR measurements in patients during VSB implantation using standard equipment, as it allows for easier and more controlled measurements of the coupling efficiency of the implant.

Cry features of healthy neonates who passed their newborn hearing screening vs. those who did not.

OBJECTIVES: Temporal and fundamental frequency (fo) variations in infant cries provide critical insights into the maturity of vocal control and hearing performances. Earlier research has examined the use of vocalisation properties (in addition to hearing tests) to identify infants at risk of hearing impairment. The aim of this study was to determine whether such an approach could be suitable for neonates. METHODS: To investigate this, we recruited 74 healthy neonates within their first week of life as our participants, assigning them to either a group that passed the ABR-based NHS (PG, N = 36) or a group that did not, but were diagnosed as normally hearing in follow-up check at 3 months of life, a so-called false-positive group (NPG, N = 36). Spontaneously uttered cries (N = 2330) were recorded and analysed quantitatively. The duration, minimum, maximum and mean fo, as well as two variability measures (fo range, fo sigma), were calculated for each cry utterance, averaged for individual neonates, and compared between the groups. RESULTS: A multiple analysis of variance (MANOVA) revealed no significant effects. This confirms that cry features reflecting vocal control do not differ between healthy neonates with normal hearing, irrespective of the outcome of their initial NHS. CONCLUSIONS: Healthy neonates who do not pass the NHS but are normal hearing in the follow-up (false positive cases) have the same cry properties as those with normal hearing who do. This is an essential prerequisite to justify the research strategy of incorporating vocal analysis into NHS to complement ABR measures in identifying hearing-impaired newborns.

Using ASSR with narrow-band chirps to evaluate hearing in children and adults.

PURPOSE: All studies concerning the reliability and threshold prediction of auditory steady-state responses (ASSR) focused on a particular group of patients. The present article evaluates the use of narrow-band, chirp-evoked ASSR for testing hearing in adults and children of all ages and with different types of hearing loss, as well as normal hearing. The aims are: to determine whether there are possible influencing factors, mainly the degree of hearing loss; and to validate the clinical value of using ASSR with chirp-stimuli. METHODS: This is a retrospective study of 667 patients who had been diagnosed with and treated for hearing loss at our tertiary referral center. The following results were compared: ASSR to pure tone audiometry (PTA); click-ABRs to PTA; and click-ABRs to ASSR. We then calculated mean, median and standard deviation. A regression analysis was used to examine the correlation between: ASSR and click-ABRs; "estimated" audiogram and PTA; click-ABRs and PTA; and ASSR and PTA. RESULTS: We found significant correlations at all frequencies when comparing ASSR to click-ABRs, click-ABRs to PTA, and ASSR to PTA. Concerning the degree of hearing loss, there were significant differences between the patients with normal hearing and those with moderate-to-profound hearing loss. CONCLUSION: ASSR with narrow-band chirps are a reliable tool for estimating hearing thresholds in children and adults with all kinds of hearing loss. We have demonstrated that threshold differences between PTA and ASSR are negligible in the clinical routine. The "estimated" ASSR audiogram is a good approach for communicating ASSR results to the average user.

Intraoperative determination of coupling efficiency of Carina® middle ear implant by means of auditory evoked potentials.

OBJECTIVE: The Carina® implant system is a fully implantable active middle ear implant, which can be coupled to various structures in the middle ear, depending on the nature of the hearing loss and the middle ear anatomy. Currently, there is only one method for determining the coupling efficiency of the actuator of this implant system, and this is limited to incus coupling. DESIGN: The proposed method is based on the intraoperative recording and evaluation of auditory brainstem responses (ABRs) while directly stimulating the hearing system via the actuator. The acoustic stimulation was achieved using an optimised broadband chirp stimulus (CE-Chirp®). STUDY SAMPLES: This study included 10 subjects having moderate to severe sensorineural or mixed hearing loss. RESULTS: The intraoperative ABR measurements show, that it is possible to derive reliable AEP thresholds via the actuator of the implant. The ABR thresholds correlate well with preoperative BC PTA4 thresholds (r = 0.87) while the postoperative OC-direct thresholds (in situ audiogram via the implant) correlate with r = 0.77. CONCLUSION: The results demonstrated that the direct actuator stimulation allow for reliable intraoperative ABR measurements and that the proposed method can be used to estimate the coupling efficiency of the actuator and facilitate its positioning.

Evaluation and therapy outcome in children with auditory neuropathy spectrum disorder (ANSD).

OBJECTIVES: The aims of the present study are to: describe diagnostic findings in patients with auditory neuropathy spectrum disorder (ANSD); and demonstrate the outcomes of different therapies like hearing aids (HAs) or cochlear implantation. METHODS: 32 children were diagnosed and treated at our tertiary referral center and provided with HAs or cochlear implants (CIs). All of them underwent free-field or pure-tone audiometry. Additionally, otoacoustic emissions (OAEs), impedance measurements, auditory brainstem responses (ABRs), auditory steady-state responses (ASSR), electrocochleography, and cranial magnetic resonance imaging (cMRI) were all performed. Some patients also underwent genetic evaluation. Following suitable provision pediatric audiological tests, psychological developmental diagnostic and speech and language assessments were carried out at regular intervals in all the children. RESULTS: OAEs could initially be recorded in most of the children; 17 had no ABRs. The other eight children had a poor ABR morphology. Most of the children had typical, long-oscillating cochlear microphonics (CMs) in their ABRs, which was also observed in all of those who underwent electrocochleography. Eight children were provided with a HA and 17 received a CI. The functional gain was between 32 and 65 decibel (dB) with HAs and between 32 and 50 dB with CI. A speech discrimination level between 35 and 100% was achieved during open-set monosyllabic word tests in quiet with HA or CI. With the Hochmair-Schulz-Moser (HSM) sentence test at 65 dB SPL (sound pressure level), 75% of the children with a CI achieved a speech discrimination in noise score of at least 60% at a signal to noise ratio (SNR) of 5, and four scored 80% or higher. Most of the children (72%) were full-time users of their devices. All the children with a CI used it on a regular basis. CONCLUSION: Only a few case reports are available in the literature regarding the long-term outcomes of ANSD therapy. The present study reveals satisfactory outcomes with respect to hearing and speech discrimination in children with CIs or HAs. The nearly permanent use of the devices reflects a subjective benefit for the children. Provision with a suitable hearing device depends on audiological results, the speech and language development of an individual child, and any accompanying disorders. Repeated audiological evaluations, interdisciplinary diagnostics, and intensive hearing and speech therapy are essential for adequate rehabilitation of this group of children.

Intraoperative Estimation of the Coupling Efficiency and Clinical Outcomes of the Vibrant Soundbridge Active Middle Ear Implant Using Auditory Brainstem Response Measurements.

Purpose This study intraoperatively measured the coupling efficiency of the Vibrant Soundbridge (VSB), with the aim of avoiding revision surgery due to insufficient outcome. This method can also be used to test the integrity of the implant at the end of the implantation surgery and to evaluate aided thresholds. In addition, this method makes it possible to objectively test how well the VSB has been fitted, provide assistance in fitting handicapped patients or children, evaluate hearing degradation, or test for a drop in coupling efficiency before revision surgeries. In order to analyze the feasibility of these new VSB-aided auditory brainstem response (ABR) thresholds, they were compared to behavioral thresholds from the Vibrogram and the preoperative bone conduction thresholds. Method The study included 30 patients with mild-to-severe hearing loss implanted with a VSB (VORP503). Intraoperative ABR thresholds during the VSB implantation were recorded using a VSB-optimized chirp stimulus. The new method is compared to the bone conduction threshold of the study sample and the aided Vibrogram thresholds. Speech intelligibility results up to 24 months after surgery are also presented. Results A reliable correlation between the bone conduction thresholds and the intraoperative ABRs was found and was higher in comparison to the Vibrogram. Furthermore, speech intelligibility outcomes were stable over time. Conclusion ABR measurements can be used intraoperatively to estimate the coupling efficiency of the VSB and test the integrity of the implant at the end of surgery.

Hearing Impairment in Old Age.

BACKGROUND: Hearing impairment associated with old age (presbycusis) is becoming more common because the population is aging. METHODS: This review is based on publications retrieved by a selective search in Medline and Google Scholar, including individual studies, meta-analyses, guidelines, Cochrane reviews, and other reviews. RESULTS: The cardinal symptom of presbycusis is impaired communication due to bilateral hearing impairment. Patients may be unaware of the problem for a long time because of its insidious progression. Evidence suggests that untreated hearing impair- ment in old age can have extensive adverse effects on the patient's mental, physical, and social well-being. Early detection is possible with the aid of simple diagnostic tests or suitable questionnaires. In most cases, bilateral hearing aids are an effective treatment. Surgery is rarely indicated. For patients with uni- or bilateral deafness, a cochlear implant is the treatment of choice. These treatments can improve many patients' quality of life. CONCLUSION: The small amount of evidence that is currently available suggests that presbycusis is underdiagnosed and under- treated in Germany. Early detection by physicians of all specialties, followed in each case by a specialized differential diagnostic evaluation, is a desirable goal.

Cervical vestibular evoked myogenic potentials via air conduction delivered by either sequentially or quasi-simultaneously presented narrow-band chirp stimuli.

OBJECTIVE: To produce sound-evoked cervical vestibular evoked myogenic potentials (cVEMPs). These are widely used for the diagnosis of peripheral vestibulopathies and disturbances of the sacculocollic reflexes. The main, sensitive, frequency for eliciting cVEMPs has been shown to be around 500 Hz. DESIGN: Narrow-band chirps in different frequency ranges (middle frequencies of 0.5, 1, 2 and 4 kHz) will be used for sequential and quasi-simultaneous stimulation of the cervical vestibular organ. As benchmarks, peak-to-peak p13 and n23 amplitudes were analysed. Study samples: The pilot study used five normal-hearing subjects (mean age 38.6 years) none of whom have balance disorders. RESULTS: From 40 measurements, p13 and n23 could be identified in a total of 34 detected cVEMPs. As expected, amplitudes were highest at 500 Hz, followed by 1, 2 and 4 kHz. Using the quasi-simultaneous stimulation method led to a slight reduction in cVEMP amplitudes, but these remained in the same order according to magnitude: 0.5, 1, 2 and 4 kHz. CONCLUSION: Sequential and quasi-simultaneous narrow-band chirps are effective for evoking cVEMPs. High amplitudes contribute to fast identification across an extended frequency range (0.5-4 kHz) and also contribute to a reduction in examination time and overall sound exposure.

Characterization of vertigo and hearing loss in patients with Fabry disease.

BACKGROUND: Fabry Disease (FD) is an X-linked hereditary lysosomal storage disorder which leads to a multisystemic intralysosomal accumulation of globotriaosylceramid (Gb3). Besides prominent renal and cardiac organ involvement, patients commonly complain about vestibulocochlear symptoms like high-frequency hearing loss, tinnitus and vertigo. However, comprehensive data especially on vertigo remain scarce. The aim of this study was to examine the prevalence and characteristics of vertigo and hearing loss in patients with FD, depending on renal and cardiac parameters and get hints about the site and the pattern of the lesions. METHODS: Single-center study with 57 FD patients. Every patient underwent an oto-rhino-laryngological examination as well as videonystagmography and vestibular evoked myogenic potentials (VEMPs) and audiological measurements using pure tone audiometry and auditory brainstem response audiometry (ABR). Renal function was measured by eGFR, cardiac impairment was graduated by NYHA class. RESULTS: More than one out of three patients (35.1%) complained about hearing loss, 54.4% about vertigo and 28.1% about both symptom. In 74% a sensorineural hearing loss of at least 25 dB was found, ABR could exclude any retrocochlear lesion. Caloric testing showed abnormal values in 71.9%, VEMPs were pathological in 68%. A correlation between the side or the shape of hearing loss and pathological vestibular testing could not be revealed. CONCLUSIONS: Hearing loss and vertigo show a high prevalence in FD. While hearing loss seems due to a cochlear lesion, peripheral vestibular as well as central nervous pathologies cause vertigo. Thus, both the site of lesion and the pathophysiological patterns seem to differ.

Comparison of click auditory brainstem response and chirp auditory steady-state response thresholds in children.

OBJECTIVES: During the last twenty years, auditory steady-state responses (ASSRs) are being used as an alternative and adjunct to the auditory brainstem response (ABR) for threshold estimation. This study aims at comparing and finding correlations between air-conduction thresholds using the traditional click ABR and the relatively recently used chirp ASSR test methods, for a large pediatric population. METHODS: One hundred and thirty children referred to our Clinic from Hospitals and Clinics of Western Greece ranging in age from 5 to 79 months (mean age = 32.7 ±â€¯14.0 months) participated prospectively. RESULTS: Strong and statistically significant correlations were found between the average of the 1000, 2000 and 4000 Hz chirp ASSR thresholds and click ABR thresholds (rs = .826, p < .001), and the average of the 2000 and 4000 Hz chirp ASSR and click ABR thresholds (rs = .824, p < .001). Additionally, there have been measurements for some children with hearing loss in the severe-to-profound range during the ASSR test, but no ABR at the upper limits of the equipment. Click ABR and chirp ASSR thresholds averaged at 2000 and 4000 Hz were within 20 dB in 90% of the ears tested. CONCLUSIONS: The results of this study support the inclusion of chirp ASSRs into the pediatric test battery and indicate that they may provide an essential adjunct to the click ABR, especially in the management of very young children with severe-to-profound hearing loss.

Surgical Impact of Coupling an Active Middle Ear Implant to Short Incus Process.

INTRODUCTION: Since 1996 the active middle-ear implant Vibrant Soundbridge (VSB) is used to treat mild-to-severe sensorineural hearing losses. The former standard surgical approach for incus vibroplasty included a mastoidectomy and a posterior tympanotomy, crimping the Floating-Mass Transducer (FMT) to the long incus process. The introduction of the short process (SP) coupler allows the attachment of the FMT to the incus body making the procedure of a posterior tympanotomy unnecessary. The aim of this study was to evaluate the duration of surgery (surgical case length) and to compare the audiological results of SP coupling with the former standard surgical approach to the long incus process. MATERIALS AND METHODS: Patients undergoing an incus vibroplasty between October 2009 and February 2016 were included in this cohort study. The patients received an incus vibroplasty with crimping the FMT to the long incus process (former standard application) (n = 25) and with the SP coupler (n = 17) respectively. The surgical case length as well as the functional audiological outcome was assessed 12 months postoperatively using pure-tone audiometry and speech audiometry. RESULTS: The surgical case length was significantly shorter in the SP coupler group compared to the standard application incus vibroplasty (85 ±â€Š29 min vs. 114 ±â€Š50 min). Additionally, patients receiving the SP coupler had an increased speech perception if compared to the standard application (Freiburger monosyllables at 65 dB SPL: 76.1 ±â€Š16.1% vs. 66.2 ±â€Š23.5%). CONCLUSION: The SP coupler leads to a shortened time of surgery and by the less invasive surgery to reduced risks for facial nerve and chorda tympani. Speech perception is significantly improved by SP coupling compared to classic long incus coupling.

Cardiac and renal dysfunction is associated with progressive hearing loss in patients with Fabry disease.

BACKGROUND: Fabry disease (FD) is an X-linked recessive hereditary lysosomal storage disorder which results in the accumulation of globotriaosylceramid (Gb3) in tissues of kidney and heart as well as central and peripheral nervous system. Besides prominent renal and cardiac organ involvement, cochlear symptoms like high-frequency hearing loss and tinnitus are frequently found with yet no comprehensive data available in the literature. OBJECTIVE: To examine hearing loss in patients with FD depending on cardiac and renal function. MATERIAL AND METHODS: Single-center study with 68 FD patients enrolled between 2012 and 2016 at the Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery of the University of Würzburg. Every subject underwent an oto-rhino-laryngological examination as well as behavioral, electrophysiological and electroacoustical audiological testing. High-frequency thresholds were evaluated by using a modified PTA6 (0.5, 1, 2, 4, 6, 8) and HF-PTA (6, 8 kHz). Renal function was measured by eGFR, cardiac impairment was graduated by NYHA class. RESULTS: Sensorineural hearing loss was detected in 58.8% of the cohort, which occurred typically in sudden episodes and affected especially high frequencies. Hearing loss is asymmetric, beginning unilaterally and affecting the contralateral ear later. Tinnitus was reported by 41.2%. Renal and cardiac impairment influenced the severity of hearing loss (p < 0.05). CONCLUSIONS: High frequency hearing loss is a common problem in patients with FD. Although not life-threatening, it can seriously reduce quality of life and should be taken into account in diagnosis and therapy. Optimized extensive hearing assessment including higher frequency thresholds should be used.

Device optimised chirp stimulus for ABR measurements with an active middle ear implant.

OBJECTIVE: Active middle ear implants are widely used to treat adults and children with sensorineural, conductive, or mixed hearing loss. Currently, there is no adequate method to determine the performance of active middle ear implant systems. DESIGN: The proposed method is based on measuring the auditory brainstem response while stimulating the hearing system via the active middle ear implant (Vibrant SoundbridgeTM, VSB; MEDEL, Austria). The acoustic stimulation was achieved via an optimised chirp stimulus (CE-Chirp), implemented in the Eclipse system (Interacoustics, Denmark). To compensate for the frequency-specific delays in the VSB system, the underlying model function of the CE-Chirp was adjusted accordingly (VSB-CE-Chirp). Study samples: The study includes 12 subjects having mild to profound sensorineural, conductive or mixed hearing loss. RESULTS: The use of an optimised VSB-CE-Chirp instead of the CE-Chirp increases significantly the ABR wave V amplitudes (1.63 times) and so also increases their identifiability (by 15.2%). On average, wave V could be identified at a 7.5 dB lower stimulation level. CONCLUSION: The constructed VSB-CE-Chirp stimulus, after it had been transmitted through the VSB system, follows well the shape of the original CE-Chirp. Preliminary measurements in VSB patients demonstrated a significantly improved ABR amplitude with the VSB-CE-Chirp.

Band limited chirp stimulation in vestibular evoked myogenic potentials.

Air conducted vestibular evoked myogenic potentials (VEMP) can be elicited by various low frequency and intense sound stimuli, mainly clicks or short tone bursts (STB). Chirp stimuli are increasingly used in diagnostic audiological evaluations as an effective means to obtain acoustically evoked responses in narrowed or extended frequency ranges. We hypothesized in this study that band limited chirp stimulation, which covers the main sensitivity range of sound sensitive otolithic afferents (around 500 Hz), might be useful for application in cervical and ocular VEMP to air conduction. For this purpose we designed a chirp stimulus ranging 250-1000 Hz (up chirp). The chirp stimulus was delivered with a stimulus intensity of 100 dB nHL in normal subjects (n = 10) and patients with otolith involvement (vestibular neuritis) (n = 6). Amplitudes of the designed chirp ("CW-VEMP-chirp, 250-1000 Hz") were compared with amplitudes of VEMPs evoked by click stimuli (0.1 ms) and a short tone burst (STB, 1-2-1, 8 ms, 500 Hz). CVEMPs and oVEMPs were detectable in 9 of 10 normal individuals. Statistical evaluation in healthy patients revealed significantly larger cVEMP and oVEMP amplitudes for CW-VEMP-chirp (250-1000 Hz) stimuli. CVEMP amplitudes evoked by CW-VEMP-chirp (250-1000 Hz) showed a high stability in comparison with click and STB stimulation. CW-VEMP-chirp (250-1000 Hz) showed abnormal cVEMP and oVEMP amplitudes in patients with vestibular neuritis, with the same properties as click and STB stimulated VEMPs. We conclude that the designed CW-VEMP-chirp (250-1000 Hz) is an effective stimulus which can be further used in VEMP diagnostic. Since a chirp stimulus can be easily varied in its properties, in particular with regard to frequency, this might be a promising tool for further investigations.

Automated auditory response detection: Further improvement of the statistical test strategy by using progressive test steps of iteration.

OBJECTIVE: A common testing approach for automated ABR detection is to use a sequential test strategy. Repeated testing increases the error probability for a falsely detected response (Type I error rate). To compensate for this effect, the statistically critical test value must be increased with each test step. The aim of the study was to improve response detection by a reduction of the number of test steps using a progressively increasing test step of iteration, defined here as step width. DESIGN: A progressively increasing test step width was tested with and without the table-related testing (adjusting the critical test value to each test step) proposed by Stürzebecher & Cebulla (2013) . For this study the same data pool was used. STUDY SAMPLE: The investigation was performed on raw EEG data collected during routine clinical measurement of frequency-specific ASSR for hearing threshold assessment. RESULTS: The reduction of the test step number combined with a progressive test step width led to a significantly improved response detection. In combination with table-related testing a slight but not significant improvement compared to table-related testing alone was revealed. CONCLUSIONS: The proposed test strategy can improve the performance of objective hearing threshold assessment and of newborn hearing screening.