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Objective To report a unique case of untoward nonauditory stimulation and cochlear implant performance deterioration after the placement of a stainless steel dental crown. Study design Clinical capsule report. Setting Tertiary academic referral center. Patient A 64-year-old female with a history of advanced otosclerosis and sequential bilateral cochlear implantation was evaluated at our institution for concerns of poor device performance. Approximately 3 years earlier, the patient had undergone stainless steel mandibular molar crown placement. After her dental procedure, she began experiencing worsening facial nerve stimulation, pain, and poor performance with the implant in her right ear. In-house device integrity testing demonstrated a series of phase reversals in the electrode voltages involving the mid-portion of the array that were consistent with otosclerosis and current shunting. Results The patient underwent removal of the mandibular crown 5 years after initial placement and experienced diminished facial nerve stimulation, resolution of pain, and a statistically significant improvement in monosyllabic word scores and speech in noise testing (Consonant-Nucleus-Consonant, 36%-76%; Bamford-Kowal-Bench Speech-in-Noise, 15-10.5 dB SNR). These findings were reproducible with serial audiometric testing over the subsequent 1.5 years, and she subjectively reported a substantial and lasting improvement in sound quality. Conclusion We present the first published report documenting resolution of nonauditory stimulation and objective device performance improvement after stainless steel crown extraction. Although we cannot make any definitive conclusions based on a single report, it remains plausible that dental work incorporating metal substrates may interfere with device function through participation in aberrant current shunting in patients with otosclerosis.

Objectives The primary objective of this study was to determine whether a revision and/or expansion of current audiologic cochlear implant candidacy criteria is warranted. Design The study design was a retrospective review of postoperative speech perception performance for 22 adult cochlear implant recipients who demonstrated preoperative Consonant Nucleus Consonant word recognition scores of 30% or higher in the best-aided condition. This criterion was chosen to exceed that specified by the North American clinical trial of the Nucleus Freedom cochlear implant system. Results The mean preoperative best-aided monosyllabic word score for the 22 patients was 41% correct. The degree of postoperative benefit for the best postoperative condition (electric only or bimodal) ranged from 10 to 68 percentage points with a mean benefit of 27 percentage points for the electric-only condition and 40 percentage points for the bimodal condition. Statistical analyses revealed highly significant differences between preoperative-aided, implant-only, and bimodal performance on Consonant Nucleus Consonant monosyllabic word recognition performance. That is, both postoperative scores--electric only and bimodal--were significantly different from one another and from the preoperative best-aided performance. Conclusions The current results suggest that a large-scale reassessment of manufacturer and Medicare preoperative audiologic candidacy criteria for adults is warranted to allow more hearing-impaired individuals to take advantage of the benefits offered by cochlear implantation.

OBJECTIVE Susac syndrome is a disease condition of unknown cause consisting of vestibulocochlear dysfunction, retinopathy, and multifocal encephalopathy derived from microangiopathy of the ear, retina, and brain, respectively. We present a unique case of bilateral cochlear implantation in a Susac syndrome patient and seek to describe in detail the specific nature of the otologic manifestations of this disease. STUDY DESIGN Clinical records of 23 patients diagnosed with Susac syndrome were reviewed. Analysis included demographics, clinical course, and audiometric data. An additional review of relevant vestibulocochlear data is undertaken among the approximately 100 previously reported cases. RESULTS Of the 23 patients with Susac syndrome, 19 (83%) were women. Mean age was 36 years, ranging from 19 to 69 years. Ten patients (43.5%) reported a fluctuating hearing loss, 14 (61%) reported tinnitus, and 13 (56.5%) noted vertigo. Eleven patients (48%) presented with bilateral symptoms, and 12 (52%) were unilateral. In the 34 affected ears, the pure-tone average was 41.5 dB, and the mean percent hearing loss was 26.4%. Forty-seven percent of the affected ears had American Academy of Otolaryngology-Head and Neck Surgery hearing classification type A. Only 26.5% of the affected ears had 100% word recognition. Statistical analysis supported an overall "upsloping" pattern of hearing loss. Bilateral simultaneous cochlear implantation was successful in restoring significant hearing in our patient. CONCLUSION Susac syndrome is a rare and potentially devastating disease. Hearing loss is quite variable. Low- and mid-range frequencies seem to be most commonly affected. Patients whose hearing loss meets criteria should be considered for cochlear implantation.

A decrease in cerebrospinal fluid pressure may result in an endolymphatic hydrops through a patent cochlear aqueduct or through the fundus of the internal auditory canal. This hydrops typically leads to low-frequency sensorineural hearing loss. We describe the case of a man who presented with a subjective and objective hearing loss in addition to a headache 4 days after he had undergone a dural puncture. We treated him with a standard epidural blood patch. Immediately after treatment, his hearing improved and his headache resolved.

As of 2014 more than 1200 patients have received a cochlear implant (CI) at Oslo University Hospital (OUS) and approximately half of them have been children. The data obtained from these patients have been used to develop a comprehensive database for a systematic analysis of several objective measurements and programming measurements. During the past 10 years, we have used an objective measurements protocol for our CI surgeries. Our intra-operative protocol includes: Evoked Compound Action Potentials (ECAP), visually observed Electrically evoked Stapedius Reflex Threshold (ESRT), and electrode impedances. Post-operative (Post-OP) programming sessions typically begin 4-6 weeks after surgery and continue on a scheduled basis. The initial programming data include threshold levels (T-levels) and comfortable levels (C-levels) for the different patient age groups. In this study, we compared initial stimulation levels and stimulation levels after at least 1 year of CI with objective measurements obtained intra-operatively.This study focused on the development of a comprehensive database of detailed intra-operative objective measures and post-OP programming measurements from a group of 296 CI patients who received the same type of CI and electrode configuration (Cochlear Corporation CI with Contour electrode). This group included 92 bilateral CI patients. Measurements from 388 CI devices were studied. Patients were divided into 5 different age groups at the age of implantation: 0-2, 2-5, 5-10, 10-20, and above 20 years in order to investigate age-related differences in programming levels and objective measurements. For the comparison analysis we used T- and C-levels obtained after the last day of initial programming and also after at least 1 year implant use. These programming levels were then correlated with some of the intra-operative objective measurements.T-levels were found to be the lowest for the youngest patient group and increased with age. C-levels varied within age groups and frequency range. Patients above 20 years of age had the highest comfort levels in the low to mid-frequencies (electrodes 22-8) and the lowest comfort levels in the high-frequency range (electrodes 1-7). Correlation coefficients between intra-operative objective measurements and programming levels were found to be in the range of no correlation to moderate correlation. Adult patients had the most significant correlation coefficients between ECAP thresholds and T-levels in the low frequencies. The younger patients aged 10-20 years and 5-10 years had more significant correlations in the higher frequency channels compared to the other age groups. Intra-operative visually observed ESRTs and electrode impedances were not significantly correlated with initial or stable programming levels for the children or adults.Analyzing initial and follow-up mapping levels from previous patients is very important for a CI Center in terms of quality control. The mean T/C-levels reported in this study can provide guidance to our programming audiologists and help them determine the initial programming levels to be stored in the speech processor, especially for very young patients. Unfortunately intra-operative objective measures in our study, such as ECAP, ESRT, and electrode impedances did not provide statistically significant correlations that may help to predict the programming T- and C-levels for all patients. However, we have observed cases where the intra-operative objective measures of ESRT and TECAP profiles were very similar to an individual's MAP profile. It was not possible, however, to determine why some patients did not have an objective measures profile that was similar to their programming levels profile.

COCHLEAR IMPLANT SOFT FAILURES CONSENSUS DEVELOPMENT CONFERENCE STATEMENTThis Consensus Statement was prepared by a panel of experts representing the fields of otolaryngology, audiology, speech and language pathology, communication science, and engineering. Representatives to the conference were app

Illustrate long-term follow-up clinical and histologic data from a patient with unilateral multichannel cochlear implantation.Case report.Clinical history, evolution of audiometric findings, and results of temporal bone histopathology of a patient implanted with a Nucleus 22 system in the right ear were analysed and interpreted.Audiometry showed severe bilateral sensorineural hearing loss, which progressed in the non-implanted ear postoperatively. With the implanted ear, speech perception was excellent postoperatively and remained stable over 5 years. Histology showed a relatively small number of spiral ganglion cells bilaterally.Cochlear implantation can provide stable hearing in light of deteriorating hearing loss in the non-implanted ear. Only a small number of surviving ganglion cells were necessary for the implant.

Contralateral masking was investigated in cochlear implant users with residual hearing in the non-implanted ear. Threshold elevations for acoustic probes were observed when electrical maskers were presented in the opposite ear. Also, threshold elevations for electrical probes were observed when acoustic contralateral maskers were presented. The amount of threshold shift expressed in decibels charge or decibels sound pressure level produced by either contralateral acoustic or electric maskers was within the range found in normal listeners for similar stimuli (i.e. 4–8 dB). There was a correlation between the sensation level of acoustic maskers and the maximum amount of masking observed which is consistent with data for normally hearing subjects. The width of the masking patterns was similar to that expected from forward masking patterns in severely sensorineurally impaired ears and implanted ears. The maximum amount of acoustic masking tended to occur for electrode positions that were more basal than expected from characteristic frequency positions. However, where a relatively high-frequency 4-kHz masker could be used, there was a good match between the characteristic frequency position of the maximum threshold elevation and that of the masker.

We have developed a procedure to measure the averaged stapedius muscle reflex in response to electrical stimulation (AESR) with a cochlear implant. The AESR, as activated by ipsilateral stimulation with a cochlear implant, was investigated intra-operatively in a series of 12 children. After the cochlear implant was placed into the cochlea and secured by the surgeon, an electromyographic (EMG) needle electrode was gently placed into the stapedius muscle. During stimulation of the cochlear implant, the stapedius reflex was monitored visually (VESR) and as an averaged EMG response (AESR). Consistent AESRs were obtained in 7 of the 12 children. These measures provide a method to obtain stapedius muscle responses that may be helpful in the programming oi young children with cochlear implants. Comparative post-operative measures were also obtained, including behavioral threshold levels, behavioral comfort levels, and the contralateral stapedius reflex threshold (ESR) on selected electrodes.

This study outlines a series of experiments using the neural response telemetry (NRT) system of the Nucleus CI24M cochlear implant to measure the electrically evoked compound action potential (EAP). The goal of this investigation was to develop a protocol that allows successful recording of the EAP in a majority of CI24M cochlear implant users.Twenty-six postlingually deafened adults participated in this study. A series of experiments were conducted that allowed us to examine how manipulation of stimulation and recording parameters may affect the morphology of the EAP recorded using the Nucleus NRT system.Results of this study show consistent responses on at least some electrodes from all subjects. Cross-subject and cross electrode variations in both the growth of the response and the temporal refractory properties of the response were observed. The range of stimulus and recording parameters that can be used to record the EAP with the Nucleus NRT system is described.Using the protocol outlined in this study, it is possible to reliably record EAP responses from most subjects and for most electrodes in Nucleus CI24M cochlear implant users. These responses are robust and recording these responses does not require that the subject sleep or remain still. Based on these results, a specific protocol is proposed for measurement of the EAP using the NRT system of the CI24M cochlear implant. Potential clinical implications of these results are discussed.

During recent years, cochlear implantation has become an established treatment option for some patients with auditory neuropathy spectrum disorder (ANSD). In a study from Berlin et al. (2010), 85% ...

Objective Superficial siderosis of the central nervous system (SSCN) results after chronic subarachnoid hemorrhage. Consequent demyelination, particularly of the cochleovestibular nerve and cerebellum, causes auditory-vestibular dysfunction. Predominant symptoms include progressive sensorineural hearing loss, imbalance, and ataxia. Despite characteristic auditory-vestibular involvement, SSCN is not well known among the hearing health community. Study design Clinical records of 49 patients diagnosed with SSCN were reviewed. Analysis included review of demographic, audiometric, and vestibular data of the largest sample to date and comparison to 31 audiovestibular case reports in the literature. Results Hearing loss and disordered balance were reported by 92% and 67% of patients, respectively. Results suggest variable but substantial auditory-vestibular involvement related to SSCN. Hearing loss is typically progressive, sloping, and asymmetric and exceeds hearing loss expected based on age or sex. Decreased word recognition is possible and traditional amplification may fail to provide benefit. Conclusion SSCN is a destructive disorder affecting the auditory-vestibular system. Although not a common diagnosis, SSCN may be more prevalent than clinicians realize. Site of lesion may be anywhere within the auditory-vestibular system from the inner ear to the cortex, although the cochleovestibular nerve and cerebellum are particularly vulnerable. The progressive retrocochlear nature of the disorder makes differential diagnosis difficult and development of effective treatment options challenging. It is essential that audiologists and otologists recognize this uncommon cause of sensorineural hearing loss and balance disorder and the implications for evaluation, treatment, and counseling.

Test results and management data are summarized for 260 patients with diagnoses of Auditory Neuropathy Spectrum Disorder (ANSD). Hearing aids were tried in 85 of these patients, and 49 patients tried cochlear implants. Approximately 15% reported some benefit from hearing aids for language learning, while improvement in speech comprehension and language acquisition was reported in 85% of patients who were implanted. Approximately 5% (13/260) of the total population developed normal speech and language without intervention. Patients were diagnosed at our laboratory (n=66) or referred from other sites (n=194), and all showed absent/grossly abnormal auditory brainstem responses (ABR), often 'ringing' cochlear microphonics, and the presence or history of otoacoustic emissions. Etiologies and co-existing conditions included genetic (n=41), peripheral neuropathies (n=20), perinatal jaundice and/or anoxia and/or prematurity (n=74). These patients comprise 10% or more of hearing impaired patients; their language acquisition trajectories are generally unpredictable from their audiograms.

Publisher Summary This chapter reviews that the whisper test and tuning fork testing are two approaches that have long been used as informal evaluations of hearing. Current audiometric testing techniques easily provide considerably more information to help distinguish the type and the degree of hearing loss. Audiometric testing is used to quantify hearing loss, and to assist in the differential diagnosis of ear and balance disorders. The chapter discusses that a comprehensive audiologic test battery provides valuable information for evaluating and managing the dizzy patient, and is needed for the evaluation of any patient with unexplained symptoms or signs of a vestibular disorder. The chapter examines the major components of the audiologic test battery through clinical cases with specific attention given to the test findings associated with vestibular dysfunction. The audiologic test findings are explored through clinical case evaluations combined with medical, radiological, and vestibular evaluations provide aid to the comprehensive evaluation of the dizzy patient.

Background: Considered a rare disorder, superficial siderosis of the central nervous system (SSCN) has become more frequently diagnosed in recent years. As it is characterized by progressive sensorineural hearing loss, patients' needs may surpass the capability of hearing aid technology. Despite the retrocochlear nature of the disorder, patients have undergone cochlear implantation (CI) with varying success. Purpose: To summarize the issues surrounding cochlear implant candidates with SSCN as well as highlight trends in performance postimplantation. Research Design: Retrospective case reports of seven cochlear implant candidates detail the symptoms, typical audiologic presentation, and array of clinical issues for patients with this progressive and potentially fatal disease. Results: Despite the retrocochlear component of a hearing loss caused by SSCN, cochlear implantation may be a viable option. Conclusions: It is essential that the CI audiologist not only be aware of the disorder but also be well versed in the resulting implications for the cochlear implant process. A more thorough case history, an expanded candidacy test battery, and knowledge of the typical presentation of SSCN are critical. The diagnosis of SSCN will impact expectations for success with the cochlear implant, and counseling should be adjusted accordingly.

Cochlear implant recipients have demonstrated remarkable increases in speech perception since US FDA approval was granted in 1984. Improved performance is due to a number of factors including improved cochlear implant technology, evolving speech coding strategies, and individuals with increasingly more residual hearing receiving implants. Despite this evolution, the same recommendations for pre- and postimplant speech recognition testing have been in place for over 10 years in the United States. To determine whether new recommendations are warranted, speech perception performance was assessed for 156 adult, postlingually deafened implant recipients as well as 50 hearing aid users on monosyllabic word recognition (CNC) and sentence recognition in quiet (HINT and AzBio sentences) and in noise (BKB-SIN). Results demonstrated that for HINT sentences in quiet, 28% of the subjects tested achieved maximum performance of 100% correct and that scores did not agree well with monosyllables (CNC) or sentence recognition in noise (BKB-SIN). For a more difficult sentence recognition material (AzBio), only 0.7% of the subjects achieved 100% performance and scores were in much better agreement with monosyllables and sentence recognition in noise. These results suggest that more difficult materials are needed to assess speech perception performance of postimplant patients – and perhaps also for determining implant candidacy.

OBJECTIVE: AutoNRT is the completely automatic electrically evoked compound action potential (ECAP) measuring algorithm in the recently released Nucleus Freedom cochlear implant system. AutoNRT allows clinicians to automatically record T-NRT profiles that in turn can be used as a guide for initial fitting. The algorithm consists of a pattern recognition part that judges if the traces contain an ECAP and an intelligent flow that optimizes the measurement parameters and finds the ECAP threshold (T-NRT). The objective of this study was to determine how accurate, reliable, and fast the automatic measurements are. DESIGN: Data on more than 400 electrodes were collected as part of the multicenter clinical trial of the Nucleus Freedom cochlear implant system. T-NRT values determined by the algorithm were compared with T-NRT determinations on the same data by different human observers. Also, the time the measurements took was analyzed. RESULTS: In 90% of the cases, the absolute difference between the AutoNRT and the human observer determined T-NRT was less than 9 CL; the median absolute difference was 3 CL. A second experiment, in which a group of human observers were asked to analyze NRT data, showed high variability in T-NRT; in some cases, two experienced clinicians disagreed by more than 30 current levels. Compared with the group, AutoNRT performed as well as the "average" clinician, with the advantage that the AutoNRT threshold determinations are objective. Analysis of the timing data showed an average intraoperative measurement time of less than 20 sec per electrode with a standard deviation of 5 sec, suggesting that the total array of 22 electrodes can be measured intraoperatively in about 7 minutes on average. CONCLUSIONS: AutoNRT provides comparable accuracy to an average clinician but with the added benefit of significant time savings over manual recordings. This makes it a valuable tool for clinical measurement of ECAP threshold in cochlear implant recipients.

Objectives To review our experiences with some of the preoperative and postoperative findings in five children who were diagnosed with auditory neuropathy and were provided with cochlear implants. We describe changes in auditory function, which enabled these children to have significant improvement in their hearing and communication skills. Study Design Pre- and postoperatively, these children received complete medical examinations at Mayo Clinic, including related consultations in audiology, pediatrics, neurology, medical genetics, otolaryngology, psychology, speech pathology, and radiology. Methods These children typically had additional medical and audiological examinations at more than one medical center. The hearing assessments of these children included appropriate behavioral audiometric techniques, objective measures of middle ear function, acoustic reflex studies, transient (TOAE) or distortion product (DPOAE) otoacoustic emissions, auditory brainstem responses (ABR), and, in some cases, transtympanic electrocochleography (ECoG). After placement of the internal cochlear implant devices (Nucleus CI24), intraoperatively we measured electrode impedances, visually detected electrical stapedius reflexes (VESR) and neural response telemetry (NRT). These intraoperative objective measures were used to help program the speech processor for each child. Postoperatively, each child has had regular follow-up to assure complete healing of the surgical incision, to assess their general medical conditions, and for speech processor programming. Their hearing and communication skills have been assessed on a regular basis. Postoperatively, we have also repeated electrode impedance measurements, NRT measurements, otoacoustic emissions, and electrical auditory brainstem responses (EABR). We now have 1 year or more follow-up information on the five children. Results The five children implanted at Mayo Clinic Rochester have not had any postoperative medical or cochlear implant device complications. All of the children have shown significant improvements in their sound detection, speech perception abilities and communication skills. All of the children have shown evidence of good NRT results. All but case D (who was not tested) showed evidence of good postoperative EABR results. Otoacoustic emissions typically remained in the non-operated ear but, as expected, they are now absent in the operated ear. Conclusion Our experiences with cochlear implantation for children diagnosed with auditory neuropathy have been very positive. The five children we have implanted have not had any complications postoperatively, and each child has shown improved listening and communication skills that have enabled each child to take advantage of different communication and educational options.

Objectives: To review our intraoperative and post-operative testing protocol for cochlear implant patients. This study describes the methodologies and applications of a new technique called neural response telemetry (NRT) for the Nucleus CI24M cochlear implant system. NRT uses radiofrequency telemetry technology to measure the action potentials of the auditory nerve. Study Design: We have developed a specific protocol for intraoperative testing of the implant device before, during, and after implantation. This includes device integrity tests, visual detection of electrical stapedius muscle reflexes (VESR), and NRT. Methods: Our methodologies use the commercial software (Windows-based Diagnostic and Programming System [WIN-DPS] and NRT) for the Nucleus CI24M. We describe the details of our protocol used on all of the patients (14 adults and 14 children) who received CI24M implants at Mayo Clinic (Rochester, MN). Our protocol correlates the NRT threshold with the behavioral responses for each patient on at least four electrodes. Results: From August 1, 1998, to December 31,1998, we completed electrode integrity tests, NRT, and VESR testing intraoperatively on 12 patients with the Nucleus CI24M. We have measured normal implant function on all 28 of our CI24M patients with one exception. One of our children had a device failure after approximately 4 months as a result of head trauma. We have also obtained NRT results from an additional 10 patients postoperatively. Conclusions: The measurement of device and electrode array function is quite simple with the CI24M software. These measurements can be obtained intraoperatively as well as postoperatively. We conclude that VESR and NRT measurements can be very helpful in programming for patients with cochlear implants, especially children, because they provides us with target settings for the speech processor.

• A new device incorporating a cochlear implant speech processor and a speech-processing hearing aid for the unimplanted ear has been designed and tested with four severely hearing-impaired patients. The aim of the device is to provide a more acceptable and effective combination of electrical and acoustic signals to the two ears. When used monaurally, and binaurally in conjunction with the cochlear implant, the speech-processing hearing aid mean scores for open-set sentences, words, and consonants were as good as or better than the mean scores for the patients' own conventional hearing aids. Some patients improved much more than did others. Although not conclusive, these results are encouraging, especially as they were achieved with a laboratory prototype that did not allow the patients to become accustomed to the processor in everyday situations. ( Arch Otolaryngol Head Neck Surg. 1993;119:55-60)

We have studied the prediction of behavioral threshold and comfort values for 11 patients who use the Nucleus 22-channel cochlear implant by means of the results of electrical auditory brain stem response (EABR) procedures. For prediction purposes, EABR and behavioral testing were done in the same electrode mode configuration for three specific electrodes. The results of this investigation suggest that EABR threshold current level is consistently near the behavioral comfort current level, rather than the patient's behavioral threshold level.

Electrical auditory brain stem responses (EABR) and electrical middle latency responses (EMLR) were recorded from patients who had received the Nucleus multichannel cochlear implant system. Twenty-five sequential patients had either intraoperative or outpatient EABR testing. We also recorded EMLRs from several outpatients. EABR results were consistent among all patients tested. Wave V mean latencies were the shortest (3.82 msec) for the most apical electrode (E20) and increased slightly for the medial (E12) and basal (E5) electrodes (3.94 and 4.20 msec, respectively). Absolute latencies for all EABR component waves were observed to be 1 to 1.5 msec shorter than typical acoustic auditory brain stem response (ABR) mean latencies. We have examined the relationships between patients' EABR/EMLR and their behavioral responses to electrical stimulation. Generally, the behavioral threshold and comfort current levels were lower than the predicted values based on EABR/EMLR findings. This observation may be due in part to psychophysical loudness differences noted for pulse rates of 10 to 500 pulses per second in some of the patients that we have studied in greater detail.

A nonlinear frequency domain beamforming algorithm was evaluated as a noise reduction technique with eight cochlear implant patients, in a take‐home trial. The subjects wore the prototype device coupled to the Nucleus processor for 5–8 weeks. The subjects were tested both before and after the take‐home trial with a single noise source at 45 deg ipsilateral to the implant and with sentence type material. The results strongly favored the coupled device for noisy environments and indicated no additional benefits from a period of continued use. The subjective reports indicated that the two‐microphone coupled device had a more robust sound quality and is preferred in noisy environments to the stand alone device. Currently the performance measures are being extended to cover sentence scores in a diffuse noise field (four speakers at different locations) and the results for both noise jammer arrangements will be reported.

Bipolar electrical stimulation of the brainstem cochlear nucleus (CN) following acoustic tumor removal in an only-hearing ear can provide beneficial hearing. However, the benefits of multichannel stimulation have yet to be defined. Following removal of a second acoustic tumor in a patient with neurofibromatosis 2, a Nucleus mini-22 channel implant device was inserted with the electrode array tip from the foramen of Luschka cephalad along the root entry zone of the eighth nerve, secured by a single suture superficially in the brain stem. Initial stimulation on the sixth postoperative day indicated that electrodes 18 to 22 were capable of CN stimulation without seventh nerve stimulation. Presumed electrode migration precluded further CN stimulation 1 month later. This report illustrates the feasibility of brainstem CN stimulation with an existing multichannel system.

Temporary threshold shift (TTS) and acoustic reflex activity were observed in 20 normal hearing subjects under several different states of attention. The Zwislocki acoustic bridge (model 3) was used to monitor acoustic reflex activity. Compliance shifts (changes in relative compliance) were measured during exposure of the contralateral ear to a 1000 Hz narrow‐band noise presented at 105 dB SPL, and TTS was measured at 1000 Hz for the contralateral ear after approximately 412 min of noise exposure. These measures were taken under three different conditions or modes of attention as defined by task performance: reverie (no task performance, high auditory attention), intelligibility test, and high visual attention (visual‐motor task). Also, levels of attention, as operationally defined by levels of task performance, were considered. From the results of this and other investigations it was concluded that there is a so‐called central factor involved in acoustic reflex activity although task performance per se, ...

Prospective screening of an extremely high risk group of 137 infants cared for in the Newborn Intensive Care Unit of the James Whitcomb Riley Hospital for Children was undertaken during 1983. Auditory brain stem responses (ABR) were obtained utilizing a clinical evoked potential system (Madsen 2250). Patients were selected for screening prior to discharge or transfer to the referring hospital on the basis of one or more of the following criteria: birth weight less than 1250 grams; birth weight less than 1500 grams and ventilatory support; significant depression at birth (Apgars less than 3 and 6 at 1 and 5 minutes, respectively); seizures, meningitis, and/or sepsis. Of the original 137 infants tested, 82 passed the initial ABR, 22 conditionally passed, and 34 failed. Eighty-two infants had follow-up behavioral and audiometric testing while 20 infants died and 35 were lost to follow-up. Four infants had severe sensorineural hearing loss, each of whom had failed the initial ABR. None of the infants who initially passed or conditionally passed the ABR had sensorineural hearing loss on follow-up testing. High risk factors for sensorineural hearing loss in the neonatal period included: intraventricular/periventricular hemorrhage, apnea, family history, major malformations of the head and neck, and possibly hyperbilirubinemia and congenital infection. No relationship of sensorineural hearing loss with very low birth weight, hyponatremia, infection, seizures, or medications was found. On the basis of these data, it is suggested that electrophysiologic hearing screening of a high risk population may be delayed until 3 to 6 months of age to improve specificity of testing.

One might hypothesize that various subjects differ in the magnitude of changes in middle‐ear acoustic impedance resulting from noise stimulation. If these impedance changes are apparently different, this may indicate differential middle‐ear musculature strength among various subjects. Twenty young adults (10 females and 10 males) with normal hearing sensitivity served as subjects for the following experiment. Measures of acoustic impedance were obtained with the Zwislocki Acoustic Bridge (Grason‐Stadler, model 3) at 500 Hz under two conditions—no noise and 105 dB SPL of white noise in the contralateral ear. As might be expected, the noise resulted in easily detectable impedance changes, however, these changes were not significantly different between the subject groups. Acoustic reactance increased for both groups (females 330 Ω and males 350 Ω), while acoustic resistance decreased for both groups (females 88 Ω and males 90 Ω). Several subjects with the smallest and greatest impedance changes were later exposed to intense noise stimulation and auditory threshold shift was measured. The results of the findings regarding impedance change and temporary threshold shift will be discussed in the paper.