Prenatal Iron Deficiency and Auditory Brainstem Responses at 3 and 10 Months: A Pilot Study

PURPOSE

To examine whether prenatal iron deficiency delays auditory brainstem response (ABR) maturation in infancy.

METHODS

One hundred and fifteen full-term healthy Chinese infants with maternal and cord blood haemoglobin and serum ferritin determinations were recruited into this study. Forty-eight infants received ABR testing at 3 months, and 45 infants were tested at 10 months. Comparison of the ABR variables were made between infants with and those without evidence of prenatal iron deficiency (maternal 3rd trimester haemoglobin <110 g/L, cord blood ferritin <75 μg/L); or anaemia at 10 months (haemoglobin <110 g/L).

RESULTS

Latencies for wave V and wave III-V and I-V intervals were prolonged at 3 months in infants of anaemic mothers (effect sizes 1.02-1.19 SD). At 10 months, infants with low cord blood serum ferritin (indicating low iron stores at birth) showed longer wave I latency and possibly wave V latency also, besides demonstrating a smaller wave V amplitude (effect sizes 0.58-0.62 SD). Infants with low ferritin at birth and anemia at 10 months had longer wave III-V latency than other groups.

CONCLUSION

In full-term healthy infants, prenatal iron deficiency appears to have adverse effects on the developing central nervous system and auditory system as assessed by ABRs at 3 and/or 10 months.

Pediatric Cochlear Implant Patient Performance as a Function of Age at Implantation

OBJECTIVE

The objective of this study was to examine the effect that age at implantation has on performance of children who received multichannel cochlear implants.

STUDY DESIGN

This is a retrospective study of 295 children who were broken down into 5 age groups based on age at implantation: 1-3 years, 3-5 years, 5-7 years, 7-9 years, and 9-11 years. Speech perception test scores obtained 12, 24, and 36 months postactivation were compared for the 5 groups using repeated-measures analysis of variance.

SETTING

This study was carried out at a tertiary academic medical center.

PATIENTS

Subjects consisted of 295 children who ranged in age from 12 months to 10 years 11 months at the time they obtained their cochlear implant.

INTERVENTION

All patients received their cochlear implant at a single implant facility.

MAIN OUTCOME MEASURES

Performance on several speech perception tests was compared 12, 24, and 36 months postactivation. Performance was evaluated as a function of age at implantation.

RESULTS

Patients in all 5 groups demonstrated improved scores when compared with scores obtained preoperatively with hearing aids. Repeated-measures analysis of variance (ANOVA) revealed a significant group by time interaction for 3 of the 5 measures. For all three of these measures, children implanted at younger ages demonstrated greater gains in speech perception over time than children implanted at older ages.

CONCLUSIONS

These results are in agreement with those of previous studies indicating that early implantation facilitates improved development of speech perception skills in profoundly deaf children.

Longitudinal effects of botulinum toxin injections on voice-related quality of life (V-RQOL) for patients with adductory spasmodic dysphonia

Adductory spasmodic dysphonia is a focal dystonia of laryngeal muscles. Patients with this disorder typically have severe vocal difficulties, with significant functional, social, and emotional consequences. There is no widely accepted cure for this condition, however, botulinum toxin injections of the thyroarytenoid muscles are considered by most voice clinicians to be the state of the art treatment. Based on extensive experience treating patients for adductory spasmodic dysphonia, we feel that traditional means of voice assessment do not adequately measure either the disease severity or the treatment outcomes. That is, listening to or acoustically analyzing limited phonatory samples does not capture the functional, social, and emotional consequences of this disorder. These consequences will be reflected in a patient's voice-related quality of life (V-RQOL). Using a validated voice outcomes instrument, the V-RQOL Measure, the purpose of this study was to quantify longitudinal changes in the V-RQOL of patients with adductory spasmodic dysphonia who are undergoing botulinum toxin injections. Twenty-seven consecutive new patients presenting with dysphonia to our institution during an 18-month period were diagnosed with adductory spasmodic dysphonia, and treated patients were evaluated prospectively using the V-RQOL Measure. Results indicated that (1) V-RQOL was initially very low for these patients, (2) botulinum toxin injections improved it significantly for each injection cycle studied, and (3) the magnitude of the treatment effect appears to change across injections.

Adult cochlear implant patient performance with evolving electrode technology

OBJECTIVE

In 1998, clinical trials were initiated to evaluate the CLARION Multi-Strategy Cochlear Implant (Advanced Bionics Corp., Sylmar, CA, U.S.A.), a precurved electrode with an electrode positioning system (EPS) in adults with severe to profound hearing impairments. In 1999, clinical trials were initiated to assess the CLARION HiFocus electrode with EPS in a similar group of adults. The purpose of this retrospective study was to evaluate and compare the preoperative and 1-, 3-, and 6-month postoperative speech perception scores obtained by the first 56 patients implanted with the precurved electrode with EPS and the first 56 patients implanted with the HiFocus electrode with EPS. Speech strategy preferences were additionally noted and compared at each test interval for each group.

STUDY DESIGN

All subjects participated in preoperative testing with hearing aids and postoperative (1, 3 and 6 months) testing with either the precurved electrode with EPS or the HiFocus electrode with EPS. Demographic characteristics and preoperative and postoperative speech perception results were compared within and between the 2 groups.

SETTING

Data presented here were collected at cochlear implant programs affiliated with tertiary medical centers located in the United States and Canada that participated in the clinical trials.

PATIENTS

Patients were postlinguistically deafened adults who received a CLARION cochlear implant.

RESULTS AND CONCLUSION

Within-group evaluations revealed that both groups demonstrated significant improvements on all speech perception measures when 1-month postoperative scores were compared with scores obtained preoperatively with hearing aids. Between-group comparison of demographic data showed that the HiFocus group had a significantly higher mean age at implant and a significantly longer mean duration of deafness than the precurved electrode with EPS group. Statistical comparison of mean speech perception scores showed no significant difference between subjects using the precurved electrode with EPS versus the HiFocus electrode with EPS at the preoperative, 1-, and 3-month test intervals. At the 6-month test interval, the mean CNC Monosyllabic Word Test score obtained by the HiFocus with EPS group was significantly better than the mean score obtained by the group with the precurved electrode with EPS (p < 0.05).

Selective cricothyroid muscle reinnervation by muscle-nerve-muscle neurotization

OBJECTIVE

To determine if selective reinnervation of the cricothyroid muscle could be achieved with muscle-nerve-muscle neurotization.

DESIGN

Case series.

SETTING

Tertiary referral center.

PATIENTS

Three consecutive patients with high vagal lesions that resulted in unilateral laryngeal paralysis.

INTERVENTIONS

Patients underwent laryngeal reinnervation with ansa hypoglossi to recurrent laryngeal nerve anastomosis. In addition, patients underwent selective cricothyroid muscle reinnervation by muscle-nerve-muscle neurotization technique.

MAIN OUTCOME MEASURES

Objective and subjective improvement in voice quality and electromyographic evidence of selective reinnervation of the cricothyroid muscle.

RESULTS

All patients recovered normal or near-normal speaking voice and had normal objective measures of voice quality. They also showed electromyographic evidence of cricothyroid muscle reinnervation.

CONCLUSION

The muscle-nerve-muscle neurotization technique was successful in providing selective reinnervation of the cricothyroid muscle in our 3 patients.

Motion-specific laryngeal reinnervation using muscle-nerve-muscle neurotization

There is no current treatment method that can reliably restore physiologic movement to a paralyzed vocal fold. The purposes of this study were to test the hypotheses that 1) muscle-nerve-muscle (M-N-M) neurotization can be induced in feline laryngeal muscles and 2) M-N-M neurotization can restore movement to a paralyzed vocal fold. Muscle-nerve-muscle neurotization can be defined as the reinnervation of a denervated muscle via axons that are induced to sprout from nerves within an innervated muscle and that then traverse a nerve graft interposed between it and the target denervated muscle. A paralyzed laryngeal muscle could be reinnervated by axons from its contralateral paired muscle, thus achieving motion-specific reinnervation. Eighteen adult cats were divided into sham, hemilaryngeal-denervated, and M-N-M-reinnervated thyroarytenoid muscle groups. Five of the 6 reinnervated animals had histologic evidence of axons in the nerve graft, 4 of the 6 had evoked electromyographic evidence of crossed reinnervation, and 1 of the 6 had a return of appropriately phased adduction. This technique has great potential and should be further investigated.

The influence of age at implantation on performance with a cochlear implant in children

OBJECTIVE

This study involved the assessment of speech recognition abilities as a function of age at implantation and length of cochlear implant use in children who received the Nucleus CI22M cochlear implant.

STUDY DESIGN

Two separate analyses were performed. The first analysis involved the assessment of speech recognition performance as a function of length of time with a cochlear implant in 48 patients evaluated at 7 years of age. The second analysis involved the assessment of speech recognition performance as a function of age at implantation in 53 patients evaluated 36 months after implantation. Patients were divided into four groups based on length of implant use or age at implantation, and the results were analyzed by a repeated-measures analysis of variance.

SETTING

This study was carried out at a tertiary academic medical center.

PATIENTS

Patients consisted of children implanted with a Nucleus Multi Channel cochlear implant programmed with the SPEAK encoding strategy. Their ages at the time of evaluation ranged from 5.5 to 7.8 years. Their ages at implantation ranged from 2.4 to 14.5 years.

INTERVENTIONS

All patients received a Nucleus Multi Channel cochlear implant programmed with the SPEAK encoding strategy. Word and sentence recognition tests were administered at various ages and at several postimplantation intervals.

MAIN OUTCOME MEASURES

Performance as a function of length of cochlear implant use and as a function of age at implantation.

RESULTS

Patients performed significantly better as length of cochlear implant use increased and age at implantation decreased. When patients were tested at a fixed postimplantation time interval (36 months), there was an overall trend for patients who received the implant at a younger age to perform better in spite of being younger at the time of evaluation. However, these effects were not statistically significant for all speech recognition tests that were administered.

CONCLUSIONS

These results confirm previous findings indicating continued improvement of speech recognition with time in implanted children. Furthermore, the results support the concept of the advantage of a younger age at implantation.

Outcome of newborn hearing screening by ABR compared with four different DPOAE pass criteria

The purpose of this study is to compare the effectiveness and utility of distortion product otoacoustic emission (DPOAE) and auditory brain stem response (ABR) testing as screening methodologies suitable for universal application at a large birthing hospital. Five hundred sixty-nine neonates (1184 ears) without risk indicators for hearing loss underwent DPOAE and ABR screening before hospital discharge at birth. All ears (100%) passed the ABR screening. DPOAE results were categorized on the basis of the number of frequencies at which emissions were obtained as well as presence versus absence of a replicated response at each test frequency. Pass and refer rates varied widely, on the basis of whether the presence of DPOAE response at 2000 Hz or replication were required. With the most stringent criteria, only 64.44% of ears passed, whereas with the least stringent criteria 88.94% passed. Given that 100% of ears passed according to the gold standard of the ABR screening, these results indicate false-positive rates ranging from 11% to 35% by DPOAE screening. This discrepancy in pass and refer rates when various criteria are applied indicates the need for standardization and further comparison of appropriate pass criteria for newborn hearing screening programs.

Audiovestibular phenotype associated with a COL11A1 mutation in Marshall syndrome

BACKGROUND

Marshall syndrome is a dominant disorder characterized by craniofacial and skeletal abnormalities, sensorineural hearing loss, myopia, and cataracts, and is associated with splicing mutations in COL11A1.

OBJECTIVE

To determine the auditory and vestibular phenotypes associated with a COL11A1 splicing.

DESIGN

Clinical otolaryngologic, audiologic, vestibular, and radiologic evaluations of the auditory and vestibular systems.

SUBJECTS

Three affected individuals from a family cosegregating Marshall syndrome and a COL11A1 splice site mutation.

RESULTS

The study subjects have progressive sensorineural hearing loss that is predominantly cochlear in origin and asymptomatic dysfunction of the central and peripheral vestibular systems. Computed tomography detected no malformations of temporal bone structures.

CONCLUSIONS

The observed auditory and vestibular abnormalities are not caused by defective morphogenesis of the osseous labyrinth, but by more direct effects of the COL11A1 mutation on the membranous labyrinth and the central nervous system. The onset and degree of hearing loss associated with COL11A1 mutations are useful clinical features to differentiate Marshall syndrome from the phenotypically similar Stickler syndrome.

Auditory brain stem response in small acoustic neuromas

OBJECTIVE

The auditory brain stem response (ABR) has been criticized recently as an insensitive measure for the detection of small acoustic neuroma (AN). This study was undertaken to evaluate our experience with the efficacy of ABR in detection of small tumors.

STUDY DESIGN

Retrospective case review. Twenty-five patients with surgically proven small ANs measuring 1 cm or less were reviewed. In addition, 568 patients who underwent screening ABR were reviewed to evaluate the rate of false positive results at our institution.

RESULTS

ABR was abnormal in 92% of patients with small AN in this series. Screening ABR was abnormal in approximately 19% of cases, one-third of which were found to have AN on magnetic resonance imaging testing.

CONCLUSION

With strict adherence to optimal technique and evaluation criteria, the ABR remains a viable option for AN screening, especially in elderly patients or when there is a low index of suspicion.

Hearing loss and automobile airbag deployments

In an on-going research program, on the causation of injuries in motor vehicle accidents, at the University of Michigan Transportation Research Institute, crashes with airbags have been, and are continuing to be, investigated. In order to determine the occurrence, if any, of 'hearing problems' associated with airbag deployments, drivers and passengers who had been involved in 'airbag' automobile crashes were interviewed by telephone. From the crashes investigated, 225 attempts were made to contact drivers who were exposed to airbag deployments. From these telephone interviews, contacts were made with 177 car occupants. Only three reported that they had experienced any type of hearing-related problems subsequent to their crash. One other case is reported of a driver who had pre-crash hearing loss. It appears that permanent hearing deficit due to airbag deployment, both in cars with the steering wheel airbag alone, and in those with a passenger side airbag, is an infrequent event (1.7%) from the data of this study.

ABR hearing screening for high-risk infants

OBJECTIVE

The goals of this investigation were to determine the outcome of a high-risk newborn auditory brainstem response hearing screening program at this institution and to determine the clinical characteristics of the target population with special emphasis on the relationship between risk criteria and hearing status.

STUDY DESIGN

This study involved the prospective screening of newborns with risk indicators and a retrospective analysis of results accumulated over a 10-year period.

SETTING

The study was conducted either in the newborn nursery or outpatient audiology clinic of a tertiary health care center.

PATIENTS

Patients were 2,103 newborns presenting with one or more risk indicators for significant congenital hearing loss or delayed onset/progressive sensorineural hearing loss.

INTERVENTIONS

Diagnostic interventions involved auditory brainstem response screening at two intensity levels (25 dB and 65 to 75 dBnHL).

MAIN OUTCOME MEASURES

The main outcome measure was incidence of significant, nonmedically treatable hearing loss in this population. A secondary outcome measure was determination of incidence of hearing loss in association with different risk indicators.

RESULTS

One hundred fourteen (5.4%) infants were diagnosed with bilateral hearing loss. Twenty-three infants (1%) presented with unilateral hearing loss. Sixty seven (49%) of the 137 infants diagnosed with hearing loss presented with greater than moderate hearing loss. Nine (13.4%) of these 67 patients presented with delayed onset hearing loss that was diagnosed at appointments subsequent to the initial screening. The largest percentage of diagnosed hearing loss was found in the "craniofacial anomalies" category.

CONCLUSIONS

Auditory brainstem response hearing screening of newborns at risk for significant hearing loss is a clinically efficient and cost effective approach to early detection of significant hearing loss. For this program, the calculated cost to diagnose one hearing impaired infant from this population is $3000.

Successful cochlear implantation in a patient with MELAS syndrome

OBJECTIVE

To describe methods of assessing cochlear implant candidacy in patients with potentially significant peripheral and central nervous system (CNS) degeneration.

STUDY DESIGN

A patient with a degenerative CNS disease (MELAS syndrome) undergoing evaluation for cochlear implantation is described.

SETTING

This study took place at a tertiary care center.

PATIENT

A patient with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) who had cortical blindness and profound sensorineural hearing loss was evaluated and rehabilitated with cochlear implantation.

INTERVENTIONS

Pure-tone audiogram, behavioral responses to promontory stimulation electrical auditory brainstem response, and electrically evoked middle-latency responses (MLRs) were used to assess eighth nerve, auditory brainstem, and cortical auditory pathways. Cochlear implantation with Cochlear Corporation mini 22 implant was performed.

RESULTS

Repeatable electrically evoked MLRs and behavioral responses to promontory stimulation documented the presence of auditory cortical responses. Successful implantation resulted in open set speech recognition and communication using the auditory/oral mode.

CONCLUSION

This report describes successful implantation in a patient with MELAS syndrome and demonstrates the ability to preoperatively confirm the integrity of brainstem and cortical auditory pathways despite significant CNS degeneration.

Hearing improvement after resection of cerebellopontine angle meningioma: case study of the preoperative role of transient evoked otoacoustic emissions

In a retrospective case study of a patient with a right-sided cerebellopontine angle mass lesion, transient evoked otoacoustic emissions were robustly present despite a severe to profound sensorineural hearing loss and abnormal auditory brainstem response. These results were interpreted as suggestive of a neural site of lesion, and the potential for planned, preserved, or improved hearing by a suboccipital surgical craniotomy was considered. A gross total resection was successful. Three years postoperatively, the patient has normal hearing sensitivity and word recognition ability.

Performance with the 20 + 2L lateral wall cochlear implant

OBJECTIVE

The purpose of this study was to investigate the operating characteristics of the Nucleus 20 + 2L lateral wall cochlear implant including speech recognition results.

STUDY DESIGN

This was a prospective randomized study involving five different modes of stimulation.

SETTING

This study was carried out in an academic, tertiary referral center.

PATIENTS

The patients included in this study were adult cochlear implant candidates ages 44-74 years. Length of deafness ranged from 1 to 58 years with a variety of etiologies.

INTERVENTIONS

All patients were implanted with a 20 + 2L implant, which includes an intrascalar electrode array and an apically placed extracochlear, titanium encased ball electrode in contact with the endosteum of the apical turn. All patients underwent psychophysical and speech recognition testing in five different modes of electrode configuration.

MAIN OUTCOME MEASURE(S)

The main outcome measures included thresholds, comfort levels, dynamic ranges, and speech recognition results obtained in five electrode configuration modes.

RESULTS

Thresholds were significantly lower (repeated measures ANOVA) in both monopolar conditions when compared to bipolar mode of stimulation. A binomial statistical analysis indicated that in five of nine patients activated in all five modes of stimulation, the monopolar modes of stimulation resulted in improved speech recognition scores.

CONCLUSIONS

The results of the study demonstrate the feasibility of the use of an apical lateral cochlear wall electrode in conjunction with an intrascalar electrode array. It further demonstrated the superiority of monopolar stimulation in selected patients.

Diagnostic testing for endolymphatic hydrops

The development of a sensitive and specific diagnostic test for endolymphatic hydrops has eluded investigators for over 30 years. The absence of such a test has hampered basic and clinical research into Meniere's disease and related entities. Presently used tests are limited in their applicability because of their low sensitivity and specificity and a poor understanding of the underlying physiologic principles. Despite this, it is generally agreed that some of these studies have merit in selected situations. This article reviews the present state of diagnostic testing for endolymphatic hydrops. The use of nonspecific studies, such as basic audiometry and tests for recruitment, and "specific" studies, such as electrocochleography and dehydration testing, are critically reviewed.

Electrically evoked auditory potentials: current clinical applications in children with cochlear implants

OBJECTIVE

To summarize the current applications of auditory evoked potential in children with cochlear implants and candidates for implantation.

PATIENTS AND METHODS

Perioperative transtympanic EABR is used routinely for ear selection and to establish the electrical stimulability of the ear intended to be implanted. The perioperative transtympanic EABR is supplemented with EABR obtained immediately following the insertion of the electrode array and the seating of the implant's receiver. Postoperatively, EABR and averaged electrode voltages are used effectively to properly adjust the implant stimulus parameters and to determine whether the implant is functioning adequately. Postoperatively, cognitive evoked potentials to speech and tonal stimuli may also be obtained.

RESULTS

EABR results have contributed to effective implant placement and function. There were several significant correlations between speech recognition and cognitive evoked potential.

CONCLUSION

These measures help assure proper implant function and effective stimulus delivery.

Clinical outcome of continuous facial nerve monitoring during primary parotidectomy

OBJECTIVES

To assess whether continuous facial nerve monitoring during parotidectomy is associated with a lower incidence of facial nerve paresis or paralysis compared with parotidectomy without monitoring and to assess the cost of such monitoring.

DESIGN

A retrospective analysis of outcomes for patients who underwent parotidectomy with or without continuous facial nerve monitoring.

SETTING

University medical center.

PATIENTS

Fifty-six patients undergoing parotidectomy in whom continuous electromyographic monitoring was used and 61 patients in whom it was not used.

MAIN OUTCOME MEASURES

(1) The incidence of early and persistent facial nerve paresis or paralysis and (2) the cost associated with facial nerve monitoring.

RESULTS

Early, unintentional facial weakness was significantly lower in the group monitored by electromyograpy (43.6%) than in the unmonitored group (62.3%) (P=.04). In the subgroup of patients without comorbid conditions or surgeries, early weakness in the monitored group (33.3%) remained statistically lower than the rate of early weakness in the unmonitored group (57.5%) (P=.03). There was no statistical difference in the final facial nerve function or incidence of permanent nerve injury between the groups or subgroups. After multivariate analysis, nonmonitored status (odds ratio [OR], 3.22), advancing age (OR, 1.47 per 10 years), and longer operative times (OR, 1.3 per hour) were the only significant independent predictive variables significantly associated with early postoperative facial weakness. The incremental cost of facial nerve monitoring was $379.

CONCLUSIONS

The results suggest that continuous electromyographic monitoring of facial muscle during primary parotidectomy reduces the incidence of short-term postoperative facial paresis. Advantages and disadvantages of this technique need to be considered together with the additional costs in deciding whether routine use of continuous monitoring is a useful, cost-effective adjunct to parotid surgery.

Cognitive evoked potentials to speech and tonal stimuli in children with implants

We investigated late and cognitive (mismatch negativity, P300) auditory potentials in 14 children with cochlear implants between the ages of 4 and 12 years. Length of cochlear implant use ranged from 7 to 84 months. Three types of stimulus contrasts were used: (1) a loudness contrast consisting of a 1500 Hz tone burst presented at 75 (standard) and 90 dB sound pressure level (deviant); (2) a frequency contrast consisting of a 1500 Hz tone burst (standard) and a 3000 Hz tone burst (deviant) presented at 80 dB sound pressure level; and (3) a speech contrast consisting of "heed" (standard) and "who'd" (deviant) delivered with a roving loudness paradigm involving a randomized variation of the levels of the standard and deviant stimuli. Latencies and amplitudes of components N1, P2, N2, and P3 and a mismatch negativity were measured. Overall, there were very few missing or unidentifiable components. P3 and mismatch negativity components were identified for all subjects and all stimuli. The latencies of most components were affected by stimulus type. There was a trend for longer latencies for the speech contrast compared with the loudness or frequency contrasts. This may be a reflection of the increased processing time required for the speech stimuli because of its higher complexity. There were several significant correlations between speech recognition and cognitive evoked potential latencies. These results indicate that the clinical use of cognitive evoked potentials in children with cochlear implants is feasible and informative.

Cochlear implantation of children with minimal open-set speech recognition skills

OBJECTIVE

The purpose of this study was to evaluate the postoperative performance of 12 children who demonstrated some open-set speech recognition skills before receiving a Nucleus multichannel cochlear implant with a view toward expanding the selection criteria for cochlear implant candidacy to include children who derive minimal benefit from amplification.

DESIGN

Pre- and postoperative performance of two groups of children were compared. Group 1 consisted of 12 children who demonstrated some open-set speech recognition skills before receiving a Nucleus multichannel cochlear implant (Borderline group). Group 2 consisted of 12 children who demonstrated no open-set speech recognition skills before implantation with a Nucleus device (Traditional group). In all children, candidacy was determined based on preimplant binaural aided performance. For most subjects, the poorer ear was selected for implantation. Mean pre- and postoperative speech recognition scores of the Borderline subjects were compared to determine the benefit provided by their cochlear implants. Secondly, matched-pair analyses were used to compare the mean speech recognition scores obtained by the Borderline and Traditional subjects.

RESULTS

The scores of the Borderline group improved significantly on five of six speech recognition measures when 6 mo postoperative scores obtained with the implant were compared with preoperative test scores obtained with hearing aids. By the 12 mo postoperative interval, the scores of the Borderline group had improved significantly (p < 0.05) on all six measures. In contrast, scores obtained by the Traditional group had improved significantly on three of six measures at both the 6 and 12 mo postoperative intervals. Comparison of postoperative test scores revealed that the Borderline group scored significantly higher than the Traditional group on three of six measures at the 6 mo test interval and on six of six measures at the 12 mo test interval (p < 0.05).

CONCLUSIONS

The findings of this study indicate that both groups derive significant benefit from their cochlear implants. Although the mean preoperative audiograms for the implanted ears did not differ significantly for the two groups of subjects, members of the Borderline group exhibited significantly better speech recognition skills than the Traditional group during the first year after implantation. These findings suggest that the increased auditory experience of the Borderline subjects positively influenced their performance with a cochlear implant. The authors advocate that the selection criteria used to determine pediatric cochlear implant candidacy be broadened to include consideration of children who demonstrate minimal open-set speech recognition skills.

Patient performance with the Cochlear Corporation "20 + 2" implant: bipolar versus monopolar activation

A within-subjects comparison of monopolar versus bipolar stimulation was performed using a modified version of the Nucleus mini-22 cochlear implant, the Nucleus "20 + 2" implant. Six subjects underwent implantation with this device, which is identical to the Nucleus 22 cochlear implant with the addition of two extracochlear indifferent electrodes. These electrodes provide two monopolar modes of stimulation in addition to the standard bipolar modes used with the Nucleus 22 device. One of the indifferent electrodes is a ball placed under the temporalis muscle (MP1), whereas the second electrode is mounted on the lateral aspect of the receiver-stimulator (MP2). After a pre-experimental phase, subjects used each of three stimulation modes (BP + 1, MP1, and MP2) for a total of 4 weeks each. Variables tested with each mode included electric thresholds, comfort levels, dynamic ranges, and speech recognition. Both the MP1 and MP2 modes of stimulation required significantly less current than the bipolar mode (BP + 1) to reach threshold and comfort level. Analysis of dynamic range data also indicated a significant stimulation mode effect. However, stimulation in the various modes did not significantly affect speech recognition scores, although two subjects demonstrated significantly improved speech recognition scores when programmed in a monopolar mode.

Self-report of cochlear implant use and satisfaction by prelingually deafened adults

OBJECTIVE

Prelingually deafened adults tend to demonstrate smaller improvements in speech recognition after cochlear implantation than do postlingually deafened adults, which has led some professionals to believe that prelingually deafened adults receive only minimal benefit from a cochlear implant. The primary objective of this study was to evaluate cochlear implant use and satisfaction by prelingually deafened adults.

DESIGN

A questionnaire was administered to 12 prelingually deafened adult cochlear implant patients to evaluate cochlear implant efficacy and satisfaction. Questionnaire results were contrasted with performance on speech recognition tasks.

RESULTS

Although these patients demonstrated little or no improvements in speech recognition 12 mo postoperatively, most patients reported that they used their device regularly, that they were satisfied with their device, and that using the cochlear implant improved both their expressive and receptive communication skills.

CONCLUSIONS

Procedures other than traditional speech recognition measures should be used to evaluate cochlear implant benefit, particularly with prelingually deafened adults.

Effects of intratympanically delivered lidocaine on the auditory system in humans

Since lidocaine is used to relieve the symptoms of Meniere's disease and tinnitus, its effects on the human cochlea is of specific interest. In experimental animals, topically administered lidocaine affects cochlear electrophysiology in a specific, dose-dependent manner. In the current study, lidocaine (40 mg in 1 ml of saline) was delivered intratympanically in six patients with essentially normal hearing in an attempt to alleviate tinnitus. Auditory function was assessed by pure tone audiometry, auditory evoked brain stem responses (ABR), and transiently evoked otoacoustic emissions (TEOAE) to observe possible drug effect in the auditory system. In five patients, saline was injected prior to lidocaine for control purposes. Saline injection did not create significant changes in any of the measures. After a 2 hr follow-up period, intratympanic injection of lidocaine caused a 2 to 10 dB reduction in TEOAE level at 1 to 3 kHz frequencies. This reduction was at its maximum at the 30 min post-injection sampling point, and was followed by a slow recovery. At 2 hr post-injection, TEOAE amplitude was still 2 to 4 dB below baseline level. Pure tone thresholds were slightly affected 30 min after intratympanic lidocaine injection, but were fully recovered 1 hr after the injection. Lidocaine injection did not cause any changes in ABR latencies or amplitudes in any of the patients. These results suggest that the dose of intratympanically administered lidocaine used here has a specific effect on the organ of Corti structures in human subjects, without significantly affecting the auditory nerve or central auditory pathways. The relationship of the drug effect in conjunction with a possible effect on inner ear disorder might help to localize the site of disorder.

Successful revision of failed cochlear implants in severe labyrinthitis ossificans

Labyrinthitis ossificans may complicate the insertion of a multichannel cochlear implant in patients deafened after meningitis. Two children who initially underwent partial insertion of a 22-channel cochlear implant because of severe cochlear ossification required revision surgery after several months of unsuccessful device use. At the time of revision, resection of the car canal, tympanic membrane, malleus, and incus provided access to the lateral wall of the cochlea, permitting extensive drilling of the basal turn and a circumodiolar placement of the electrode. Functional integrity of the electronic components of the original device was documented intraoperatively, avoiding the expense of a new receiver-stimulator. Complete insertion of the active electrodes was accomplished in both cases, and electrophysiologic responsiveness to the implant was documented using intraoperative electrically evoked auditory brainstem response recordings. Postoperative performance has been similar to that of cochlear implant patients with nonossified ears. Experience with these two cases suggests that efforts to optimize electrode insertion at the original surgical procedure are appropriate and may help to avoid the disappointment of an unsuccessful cochlear implant.

Neonatal choristoma of the tongue containing glial tissue: diagnosis and surgical considerations

There are only six case reports documenting the presence of glial tissue in the tongue. Because of the small number of cases, the presentation and biologic behavior of these lesions is poorly characterized. We present the case of a 10-day-old male infant who arrived at the University of Michigan Medical Center with a history of positional dyspnea, with resultant cyanosis and bradycardia, dysphagia, and a mass at the base of the tongue. Histopathologically, this lesion was initially labeled as a hamartoma, but was ultimately defined as a choristoma based on the exclusive presentation of glial tissue in the specimen. This paper will discuss the presentation, diagnostic evaluation, and therapeutic management of this case. In addition, the role of intraoperative electrodiagnostic monitoring to preserve neuromuscular function will be addressed.

Clinical manifestations of CHARGE Association

The clinical literature regarding CHARGE Association is mostly retrospective in nature and deals largely with non-auditory issues related to the care and management of these patients with multisystem involvements. In this paper, we describe the clinical findings in 24 patients evaluated in the Division of Audiology and Electrophysiology at the University of Michigan Medical Center from 1983 to 1993. We report on the clinical manifestations of CHARGE Association in these patients with particular attention paid to their audiologic status. We discuss the relationships between auditory, ear, and craniofacial anomalies. Our review of these previously unreported cases suggests the following: (1) a variety of audiologic outcomes is possible, however, if a sensorineural or mixed hearing loss exists, it tends to be severe in degree; (2) progressive hearing loss does not appear to occur, but recurring otitis media is a probable confounding factor in the early identification of hearing loss; (3) congenital unresolved facial weakness may serve as a reliable predictor of sensorineural hearing loss; and (4) amplification use may be poor due to a number of factors. We hope to offer guidance to the professionals from assorted disciplines who participate in the care of these children.

Cochlear implantation in patients with cochlear malformations

OBJECTIVE

To report operative findings, postoperative course, and postimplantation performance in patients with cochlear malformations who underwent cochlear implantation.

DESIGN

Case study and intervention study (before-after trial). Minimum follow-up of 12 months; average follow-up of 24 months.

SETTING

Academic tertiary referral center.

PATIENTS

Six patients, including five children who underwent implantation at ages 3.5 to 13 years and one adult who underwent implantation at age 27 years. malformations included common cavity deformity (n = 1), cochlear hypoplasia (n = 2), and incomplete partition (n = 3). All patients with cochlear malformations who underwent implantation at the University of Michigan, Ann Arbor, are included, selected from a group of 196 patients so treated since 1986.

INTERVENTION

Implantation with a standard multichannel cochlear implant.

MAIN OUTCOME MEASURES

Operative findings described include round window and facial nerve anatomy and cerebrospinal fluid leak. Postoperative roentgenographic findings, electrode activation, and reason for non-use of electrodes were investigated. Standard tests of speech perception were used to compare preoperative and postoperative performance for each subject.

RESULTS

Operative findings included round window abnormalities (three patients), anomalous facial nerve (one patient), and cerebrospinal fluid leak (three patients). No surgical complications occurred. A minimum of 10 electrodes were activated for all patients. Electrode thresholds and discomfort levels were variable for several months after implantation. All patients demonstrated improved performance after implantation. Four subjects demonstrated open-set speech perception. Two other subjects, whose poor language skills precluded administration of standard tests, showed increased awareness of environmental sounds and increased vocalization after implantation.

CONCLUSIONS

Cochlear implantation can be a successful method of rehabilitation in patients with congenital deafness who have cochlear malformations.

Cochlear implant device failure: diagnosis and management

Complete, irreversible failure of the implanted receiver-stimulator of the Cochlear Corporation multichannel implant are relatively rare. However, as the implanted patient population grows, malfunctions may be expected. From the over 200 patients implanted at the University of Michigan Medical Center, 6 patients with a complete and irreversible cochlear implant receiver-stimulator failure have been identified and treated. This represents a 3% failure rate. The amount of time between initial implantation and device failure ranged from 6 months to 3.5 years. Determination of device failure was made using psychophysical, electrophysiologic, and averaged electrode voltage measurements. The measurement of the average electrode voltages proved to be useful in determining the condition of the implant. Physiologic changes causing reduced electrical excitability were ruled out using psychophysical or electrophysiologic promontory testing. All patients were successfully explanted and reimplanted.

Electrically evoked auditory brain-stem response in pediatric patients with cochlear implants

OBJECTIVE

To study the feasibility and clinical applicability of preoperative, transtympanic electrically evoked auditory brain-stem response (EABR) in a pediatric patient population with cochlear implants.

DESIGN

A descriptive study using repeated measures analyses of variance to determine if EABR measures were affected by response configuration or cochlear status.

SETTING

The operating room before cochlear implant surgery.

PATIENTS

A population-based sample of 43 patients aged 2.5 to 14.5 years who were candidates for cochlear implantation.

INTERVENTION

Stimuli consisting of brief balanced biphasic current pulses were provided by a transtympanically placed promontory needle electrode; EABR was recorded with subdermal needle electrodes on the forehead and contralateral mastoid.

MAIN OUTCOME MEASURE

Presence or absence of postoperative electrical excitability with a cochlear implant.

RESULTS

Electrically evoked auditory brain-stem responses were available from 41 of the 43 patients tested. Mean EABR threshold was 406.5 microA (SD = 118.1) for 31 patients with patent cochleas and 472 microA (SD = 91) for 10 patients with cochlear ossification. Mean wave V latency at threshold was 4.69 milliseconds (SD = 0.57).

CONCLUSION

Preoperative EABR is an integral component of the preoperative selection process for pediatric patients with cochlear implants.

Stability of hearing preservation following acoustic neuroma surgery

Identification of small acoustic neuromas has become commonplace. Frequently, affected individuals are identified prior to the development of significant hearing loss. Whereas many studies have focused on hearing preservation surgery, few have reported on stability of hearing results after resection of acoustic neuroma. Between 1985 and 1991, 36 patients underwent resection of an acoustic neuroma via a retrosigmoid, internal auditory canal approach with attempted hearing preservation. Hearing was preserved in 24 patients; 17 were available for testing for the present study. Follow-up ranged from 1.5 to 8 years. All patients underwent complete audiologic assessment; most patients also underwent auditory brainstem response testing. There was an average 6 dB increase in pure-tone average between early (1 month) postoperative and long-term postoperative test results. A binomial single subject statistic was used to assess for significant changes in speech recognition scores over time. In two subjects there was a significant decrease; however, speech recognition also improved significantly in two subjects. Five of the 17 subjects demonstrated either a significant (at least 15 dB) increase in pure-tone average or a significant decrease in speech recognition over the time-course of the study. All patients maintained usable hearing. We conclude that long-term hearing preservation is a realistic goal in selected acoustic neuroma operations.

Hearing loss from a bicycle horn

A 39-month-old child with previously documented normal hearing suffered acoustic trauma from a bicycle horn activated at his ear. Six days after the insult, a 4000-Hz 50-dB sensorineural hearing loss was found. This threshold improved to 30 dB HL over 6 months. The horn produces 143 dB peak SPL, a level clearly associated with a high risk for hair cell damage. This case shows the need for regulations limiting sound levels or requiring warning labels on potentially damaging toys and other recreational devices. Had a warning been provided, the parents of this child would not have bought the horn as a toy.

Cochlear wall titanium implants for auditory nerve stimulation

Genetically deaf dalmatian dogs and ototoxically deafened macaque monkeys were implanted with electrodes housed in cochlear wall titanium implants to assess long-term stability, tolerance, and performance. Short-term human implantation, followed by trials of stimulation, was performed in 4 unilaterally deaf patients. In the dog experiments, cochlear wall electrode stimulation produced consistent electrophysiologic thresholds that were higher, by approximately 6 dB, than those obtained with bipolar scala tympani stimulation. Clinical testing revealed electrically evoked middle latency response, auditory brain stem response, and/or behavioral detection responses in 3 of 4 patients, at levels below those for facial nerve activation and pain sensation. Electrode place discrimination studies, with controls for loudness cues, revealed near-perfect discrimination in a monkey subject. Eleven of the 12 animal implants were found to be rigidly fixed in the cochlear bone, with direct contract between bone and implant over 8% to 23% of the implant surface for the 6 implants examined in detail. These results suggest that long-term fixation of titanium cochlear wall implants occurs by virtue of intimate implant-bone contact in restricted areas. This approach to prosthetic stimulation demonstrates encouraging performance characteristics in achieving auditory activation.

The clinical differentiation between vocal cord paralysis and vocal cord fixation using electromyography

With newer techniques for laryngeal intervention, it becomes a practical necessity to understand whether an immobile cord is due to neurogenic dysfunction or cricoarytenoid fixation. An objective test for this differentiation is laryngeal electromyography, which can be done as an office procedure with a minimum of discomfort. Our experience in a clinical setting has shown laryngeal electromyography to be efficient in accurately assessing the neuromuscular status of the intrinsic laryngeal musculature.

Tinnitus suppression following cochlear implantation. A multifactorial investigation

The effects of cochlear implant on loudness, annoyance, daily duration, location, and residual inhibition of tinnitus were evaluated by a closed-ended, quantifiable questionnaire in 33 postlingually deafened patients who had received implants at the University of Michigan, Ann Arbor, between 1986 and 1990. Preoperative tinnitus was present in 85% of patients. A statistical comparison of preoperative vs postoperative loudness and annoyance indicated a significant reduction in both of these complaints postoperatively. Loudness and annoyance were significantly correlated, both preoperatively and postoperatively. Fifteen patients (54%) with preoperative tinnitus demonstrated a loudness decrease of 30% or more; 43% demonstrated an annoyance decrease of 30% or more; and 48% demonstrated a decrease of 30% or more in daily tinnitus duration. Patients who experienced a loudness or annoyance decrease of 30% or more after implantation demonstrated significantly higher preoperative levels of these complaints, suggesting that degree of tinnitus reduction after implantation may be related to preoperative loudness and annoyance levels. Contralateral tinnitus suppression was reported by 42% of patients. Residual inhibition ranging from 60 seconds to several hours was reported by 50% of patients, predominantly in the ear with the implant. Age, gender, cause of hearing loss, duration of tinnitus, cochlear implant usage, and time after implantation were not predictive of tinnitus suppression. Overall, the majority of the patients (74%) thought that their cochlear implant was helpful in tinnitus suppression, especially in the ear with the implant. Contralateral residual inhibition and tinnitus suppression suggest a central mechanism contributing to these phenomena.

A comparison of round-window and transtympanic promontory electric stimulation in cochlear implant candidates

We compared within-subjects electrical thresholds and dynamic ranges obtained with direct round-window and transtympanic promontory stimulation carried out preoperatively in 12 patients who were candidates for a cochlear implant. Square waves with frequencies of 50, 100, 200, and 400 Hz were delivered in a 50% duty cycle to both sites in each patient. With the exception of threshold at 50 Hz (promontory thresholds were lower than round-window thresholds), there were no statistically significant differences for either thresholds or dynamic ranges between the two sites of stimulation. There was a general trend for round-window thresholds to be lower and dynamic ranges larger, especially for the higher frequencies of stimulation. Mean threshold slopes for the two sites of stimulation were nearly identical.

Devices for the hearing impaired

Hearing loss can result in significant communicative and social dysfunction. Various methods of sound amplification are available for the hearing impaired. Hearing aids are becoming more technologically sophisticated, more cosmetically appealing and more commonly used. The choice of hearing aid must be individualized and depends on several factors, including the type of hearing loss, the cost of the device, the patient's work environment, motivation and vanity, and the degree of difficulty in using the hearing aid. Devices are also available to help hearing-impaired persons in specific situations where hearing aids may not be necessary. The cochlear implant is a relatively new device for use in the profoundly hearing impaired.

Auditory performance of children with cochlear ossification and partial implant insertion

The management of the profoundly deaf child with a cochlear implant poses a special challenge, particularly when total ossification of the cochlea is present. In this setting, insertion of an electrode array into a child's cochlea is often difficult. Our experience supports the feasibility of partial insertion of a multichannel implant into the basal turn of an ossified cochlea. Five children with ossified cochleae who had undergone partial implantation of a multichannel electrode were compared with the performance of matched controls who had full insertion of multichannel implants. No dramatic differences were detected during a 6- to 18-month follow-up period on selected test measures. These preliminary results suggest that active electrode number may exert a limited effect on performance with a cochlear implant. Drilling out the basal turn of an ossified cochlea in conjunction with partial insertion of a multichannel implant appears to be an acceptable surgical and rehabilitational alternative for placement of a cochlear implant prosthesis in children with complete cochlear ossification.

Prognostic value of evoked and standard electromyography in acute facial paralysis

Ninety-one patients with idiopathic (n = 62) and traumatic (n = 29) facial paralyses were available for evaluation at least 1 year after the onset of paralysis. In nine cases of idiopathic paralysis and in 12 cases of traumatic paralysis, total intratemporal nerve decompression was performed. The remaining patients were treated with steroids alone. All patients underwent evoked electromyography (EEMG) testing within 2 weeks of the onset of paralysis. Facial nerve recovery was graded using the House-Brackmann facial nerve recovery scale. Subjects were grouped according to maximal decline of compound muscle action potential (CAP), as determined by EEMG, and by level of recovery 1 year after onset of paralysis. Among patients who did not undergo surgical decompression of the facial nerve, incomplete clinical recovery (grade III or higher) was significantly associated with CAP decline of greater than 90% (p less than 0.05) for idiopathic paralysis. In contrast, there was no significant association between CAP decline of greater than 90% and clinical outcome in traumatic paralysis. These findings support previous reports of the prognostic value of EEMG in idiopathic facial paralysis, but suggest that this test may have less predictive value in the evaluation of facial paralysis as a result of trauma.

Effects of channel number and place of stimulation on performance with the Cochlear Corporation multichannel implant

The effects of active channel number and place of stimulation on auditory-only performance with the Cochlear Corporation multichannel cochlear implant were investigated in seven subjects. A balanced crossover design was employed; subjects were initially programmed with either 10 basal or the full complement of 20 to 21 active electrodes. Following a 6-month period with the initial coding strategy, subjects were programmed with the alternate configuration, which they used for an additional 6 months. Auditory-only performance on suprasegmental, phoneme (vowel and consonant) open- and closed-set speech recognition was compared between the two electrode configurations. Additionally, performance with the first configuration and performance with the second configuration 3 days following programming were also compared. While a trend for increased scores was noted with 20 electrodes, especially with open-set speech recognition tasks, none of the differences between the two configurations reached statistical significance, as indicated by a Wilcoxon test. A comparison of performance at the end of the first 6-month period and 3 days following programming with the second configuration revealed a trend for reduced scores, especially on vowel tests. Overall, our results indicate that the feature extraction coding strategy associated with the Cochlear Corporation device allows patients to function well with only 10 basal electrodes and that speech recognition is only mildly affected initially when patients are programmed with a different encoding strategy.

Effects of preoperative electrical stimulability and historical factors on performance with multichannel cochlear implant

We investigated the relationship between results of preoperative transtympanic electrical promontory stimulation, duration of deafness, postoperative implanted psychophysical results, and postoperative speech and speech sound recognition as indicated by a battery of five tests. Our subjects were 10 patients implanted with the Cochlear Corporation multielectrode implant, 1 year postimplantation, with a minimum of 17 active electrodes programmed in the bipolar + 1 mode. The results indicated that preoperative promontory thresholds, the slope of the threshold function, and the duration of auditory deprivation are excellent predictors of postoperative speech and speech sound recognition in the auditory (processor alone) mode. These results have significant implications for patient selection and counseling.

Tinnitus as a function of duration and etiology: counselling implications

Based on the data of 528 tinnitus patients, information is presented concerning: (a) conditions and/or activities that affect tinnitus severity, (b) tinnitus symptoms as a function of etiology, and (c) changes in tinnitus symptoms as a function of time since onset. The four most common conditions and/or activities that reduce tinnitus severity were sleep, listening to TV/radio, being in noise, or being in quiet. Many conditions and/or activities increased tinnitus severity. The most common detrimental activities and/or conditions were noise exposure, being in a quiet place, emotional stress, loss of sleep, and physical exhaustion. Results also revealed that tinnitus loudness and severity increased as a function of years since onset. However, tinnitus pitch tended to remain stable. Meniere's patients experienced more annoyance, depression, and interference with sleep and also reported louder tinnitus than other etiologies. Tinnitus counselling should include: (a) informing patients that it is unlikely tinnitus annoyance will change dramatically, (b) alerting patients to the usefulness of tinnitus self-help groups, (c) helping patients to minimize time spent in activities and/or conditions where tinnitus severity is increased and to maximize time in activities and/or conditions where tinnitus severity is decreased, and (d) stressing the avoidance of noise exposure because of the relationship between noise-induced hearing loss and tinnitus.

Cochlear implants in children

The resources and areas of expertise necessary to establish and maintain a successful children's cochlear implant program is discussed. Insights based on experience with a pediatric patient population are presented.

Electrical stimulation of the auditory system after labyrinthectomy

For many years labyrinthectomy has been used as a reliable surgical treatment for patients with unilateral nonserviceable hearing associated with episodic vertigo. In view of the rehabilitative potential of the cochlear implant, the role of labyrinthectomy has been questioned because of a concern to preserve structures of the auditory periphery. However, recent reports demonstrate substantial survival of spiral ganglion cells after labyrinthectomy, suggesting that such patients might be candidates for rehabilitation with cochlear implants if necessary. To address this question from a physiologic approach, we investigated the electrical stimulability of the operated ear in patients who underwent transmastoid labyrinthectomy for the management of vertigo. Ten patients were studied intraoperatively with electrically evoked middle latency response (MLR) potentials. Six of these patients were studied between 3 and 15 months postoperatively via transtympanic stimulation. Postoperatively all patients demonstrated an excitable auditory periphery and behavioral thresholds were similar to intraoperative electrophysiologic thresholds for the same stimuli. These results suggest the persistence of excitable auditory neural elements following labyrinthectomy.

Arytenoid subluxation: diagnosis and treatment

Both arytenoid subluxation and recurrent laryngeal nerve paralysis (RLNP) may result from injury to the larynx, and they may be difficult to distinguish clinically. A patient with arytenoid subluxation who was initially believed to have RLNP was treated with medialization laryngoplasty 1 year after the injury. Preoperative magnetic resonance imaging and computed tomography effectively demonstrated the cricoarytenoid subluxation, which was confirmed by intraoperative electromyography (EMG) showing normal electrical activity in the thyroarytenoid muscle. Photographs from preoperative fiberoptic laryngoscopy are presented to identify the appearance of arytenoid subluxation. Computed tomographic findings and photographs from laryngoscopy of two patients with RLNP documented by intraoperative EMG evaluation are presented to help distinguish the clinical appearance of this disorder from arytenoid subluxation. An integrated approach to the diagnosis and treatment of arytenoid subluxation is presented.

Asymmetric brain stem auditory evoked responses in infants treated with extracorporeal membrane oxygenation

Brain stem auditory evoked responses (BAERs) were obtained in 25 infants who received extracorporeal membrane oxygenation (ECMO) for severe respiratory failure. Tracings were obtained by means of a Nicolet CA-2000 averager, using a conventional paradigm. The presence or absence of replicated responses at 35 and 75 dB nHL were recorded for each ear. Interpeak latencies I-III, III-V, and I-V were measured and differences between right and left ears were compared, using a matched pair t-test. Wave III-V latencies were longer on the left than right (p less than 0.05), but no significant right-left differences for latencies I-III were noted. Sixteen percent of the infants failed hearing sensitivity criteria, 45% (10/23) had prolonged I-V latencies. At follow-up (age 4 to 12 months) 6/10 infants with prolonged I-V latencies had additional neurologic abnormalities. In this population left ear III-V latencies are prolonged versus right, and the incidence of abnormal BAERs is high. Relative prolongation of left ear III-V latencies (generated from the right brain stem) may be result of right carotid artery and/or jugular vein ligation for ECMO, and abnormal I-V latencies prognosticate future neurologic abnormalities in this population.