Effects of early auditory deprivation and stimulation on auditory brainstem responses in the rat

The purpose of this study was to investigate the effect of auditory sound deprivation or stimulation on auditory brainstem responses (ABRs) during the maturation period of the rat auditory system. At postnatal day (PND) 21, 40 newborn Norway Brown male rats were categorized into 3 groups: (i) an auditory deprivation group in which a bilateral average conductive hearing loss of 27 dB was induced; (ii) an auditory activation group exposed to 65-90 dB sound pressure level; and (iii) a control group. ABR recordings were made on PND 84. In order to compare group differences in interpeak latency (IPL), sensation level (SL), defined as stimulus intensity above threshold, was used. IPL measurements and analysis were restricted to the 20-60 dB SL range. No differences were observed in the IPLs of peaks I-IV between the three groups. Small, but not statistically significant, differences in mean estimated IPLs of peaks I-IV were shown in the ranges > 50 dB SL and < 25 dB SL. Possible confounding factors explaining the apparent discrepancy between these results and those of other animal studies are reviewed.     

Methyl mercury ototoxicity in mice determined by auditory brainstem responses

Mice of the C57 B1/6 strain were used to assess auditory deficits due to methyl mercury chloride intoxication. Auditory Brainstem Responses were obtained to pure-tone stimuli from 4 to 78 kHz. Physiologic thresholds were compared with behavioral methods for determining audibility in mice. Two dosage levels were studied; 4 and 8 mg/kg. Recordings were taken weekly, for each mouse, for 3 consecutive weeks after initial injection. Analysis of physiologic threshold and latency indicated that methyl mercury chloride causes auditory deficits at all frequencies tested with the greater effect in the higher frequencies. Additionally, latencies indicated nerve conduction hypersensitivity in the brainstem.     

Incomplete maturation of brainstem auditory nuclei in genetically induced early postnatal cochlear degeneration

In the Shaker-2 mouse mutant, a cochleo-saccular type of genetically induced inner ear degeneration occurs. Morphological signs of degeneration are evident in the 3rd postnatal week and a severe and almost total degeneration has occurred by the age of 6-9 weeks. There are no qualitative differences between the brain of the normal CBA/J mouse and that of the Shaker-2 mouse. The growth of the auditory brainstem nuclei (dorsal cochlear nucleus and ventral cochlear nucleus) in the mutant Sh-2 mouse has stopped by 14 days of age--but not in the normal CBA/J mouse. The brainstem as a whole continues to grow between 14 and 140 days of age in both strains. The early cochlear degeneration coincides with the critical period when a normal input from the peripheral receptor organ is necessary for the maturation of the central auditory pathway.     

Effects of sex on auditory brainstem responses in infancy and early childhood

The effects of sex on I-III, III-V and I-V interwave intervals and I, III, V ABR waves latency values have been studied in 171 normal children born at term, 94 males and 77 females, aged between 2 and 720 days. The obtained data confirm that latency values decrease progressively with age, and show that there is a statistically significant difference in wave III and V latency values and in III-V and I-V intervals between males and females. Moreover, these differences seem to increase with age. The authors also discuss the possible underlying mechanisms and claim that even in infancy, sex-related variability should be taken into account.     

Influence of cochlear traveling wave and neural adaptation on auditory brainstem responses

The present study investigates the relationship between evoked responses to transient broadband chirps and responses to the same chirps when embedded in longer-duration stimuli. It examines to what extent the responses to the composite stimuli can be explained by a linear superposition of the responses to the single components, as a function of stimulus level. In the first experiment, a single rising chirp was temporally and spectrally embedded in two steady-state tones. In the second experiment, the stimulus consisted of a continuous alternating train of chirps: each rising chirp was followed by the temporally reversed (falling) chirp. In both experiments, the transitions between stimulus components were continuous. For stimulation levels up to approximately 70 dB SPL, the responses to the embedded chirp corresponded to the responses to the single chirp. At high stimulus levels (80-100 dB SPL), disparities occurred between the responses, reflecting a nonlinearity in the processing when neural activity is integrated across frequency. In the third experiment, the effect of within-train rate on wave-V response was investigated. The response to the chirp presented at a within-train rate of 95 Hz exhibited the same amplitude as that to the chirp presented in the traditional single-stimulus paradigm at a rate of 13 Hz. For a corresponding experiment with bandlimited chirps of 4 ms duration, where the within-train rate was 250 Hz, a clear reduction of the response amplitude was observed. This nonlinearity in terms of temporal processing most likely reflects effects of short-term adaptation. Overall, the results of the present study further demonstrate the importance of cochlear processing for the formation of brainstem potentials. The data may provide constraints on future models of peripheral processing in the human auditory system. The findings might also be useful for the development of effective stimulation paradigms in clinical applications.     

Comparison of auditory steady-state responses and tone-burst auditory brainstem responses in normal babies

OBJECTIVE: To follow the development of tone-burst auditory brainstem response (TB-ABR) and auditory steady-state response (ASSR) thresholds in a group of normal babies through the first 6 wk of life. DESIGN: This longitudinal study involved assessment at four data-collection points. TB-ABR and ASSR thresholds to 500-Hz and 4-kHz stimuli were established in 17 full-term subjects at 0, 2, 4, and 6 wk of age. Stimulus-modulation rates for ASSR assessment were 74 Hz (for 500-Hz tones) and 95 Hz (for 4-kHz tones). TB-ABR responses were recorded to stimuli presented at 39.1 Hz. RESULTS: Mean ASSR thresholds (calibrated in dBHL) at 500 Hz ranged from 44.4 to 39.7 dB HL across the recording period, and at 4 kHz they ranged from 37.9 to 32.1 dB HL. TB-ABR thresholds (calibrated in dBnHL) were significantly lower, ranging from 36.8 to 36.2 dB nHL at 500 Hz and from 16.5 to 15.9 dB nHL at 4 kHz. However, when the stimuli used for each test were calibrated in the same units (peak equivalent dB SPL), the results were similar. That is, the differences between the two techniques were only an artifact of the calibration. ASSR thresholds were more variable than TB-ABR, particularly at the neonatal measurement point. Within-subject changes across the test period were observed for ASSR thresholds but not for TB-ABR. CONCLUSIONS: The longitudinal findings presented in this study suggest that for normal neonates, the TB-ABR technique may offer a more reliable basis for prediction of hearing levels than ASSR assessment. This is not because TB-ABR thresholds (calibrated in dBnHL) are lower, but because the response is less affected by maturational development in the first weeks of life and is less variable across subjects.     

2035例婴儿听性脑干反应与多频稳态反应阈值的比较

目的 探讨婴儿听性脑干反应(auditorybrainstem response,ABR)与多频稳态反应(auditorysteady-state response,ASSR)的关系.方法 对2035例婴儿进行ABR和ASSR检测,结果采用SPSS 17.0进行相关分析、t检验和直线回归分析.结果 ①ABR反应阈与ASSR不同频率反应阈值的相关系数为0.732～0.915 (P＜0.05).②在t检验中,ABR反应阈值与ASSR 4 kHz反应阈值差异无统计学意义(P＞0.05),其余比较差异均有意义(P＜0.05).③ABR预测ASSR0.5、1、2、4 kHz、高频均值、均值的回归方程分别为:y=0.979x-6.921,y=0.909x-1.705,y=0.948x-3.647,y=1.117x-5.113,y=1.033x-4.380,y=0.988x-4.346.结论 婴儿ABR与ASSR反应阈值具有较好的相关性,其主要是反映ASSR 4 kHz的反应阈值.     

Limits of the study of early auditory brainstem responses in the diagnoses of childhood deafness

The author presents the results of his experience concerning brain stem evoked response in children. 122 cases are put forth. It shows that although behavioral audiometry is impossible in 7% of the cases, the BERA (Brain stem Evoked Response Audiology) is not reliable in 26.5% of the treble frequencies and 36% of the bass frequencies. Thus, it is not possible to equip children with hearing aids based on this given alone.     

Estrogen treatment and age effects on auditory brainstem responses in the post-breeding Long-Evans rat

The auditory brainstem response (ABR) was recorded from 20-month-old Long Evans hooded female rats to determine if latency reductions occur from estrogen replacement. The ABR in these post-breeding age rats was also examined for reductions in response latencies as a function of adult age. Tone pip stimuli (8 and 40 kHz) were presented at 21, 51, or 81 s(-1). Aging control and ovariectomized animals showed slower response latencies for waves Ib-VI than young adults for 8 and 40 kHz stimulation at 21 s(-1). Increased stimulus rate resulted in longer latencies for all waves at 20 months. In contrast to hormone treatment effects in young adults, ABR latencies in post-breeding age estrogen-treated animals were not reduced, consistent with a general decrease in CNS responsiveness to estrogen steroids associated with age. The results also suggest that sensorineural modifications in the auditory system which prolong ABR latencies can occur early in the aging process of adult female subjects.     

Development of brainstem auditory evoked responses in the hamster

The hamster is relatively immature at birth compared with other mammalian species. Because of the amount of maturation that occurs postnatally, the development of the peripheral auditory system of the hamster has generated a great deal of interest. However, indices of the developing functional capabilities of the central auditory system of the hamster are lacking. The following study investigated the ontogeny of brainstem auditory evoked responses (BAERs) to clicks in young hamsters. The general maturational trends noted for other species were found for the hamster. The major peaks of the BAER decrease in latency at the same time relative to birth and at the same rate in the hamster as in the cat and rat. Some maturational events such as the onset of a recordable BAER, appearance of the late peaks and increase in amplitude of the late peaks occur later, relative to birth, in the hamster than in the other species. Development delays in the hamster make it an attractive model for studying postnatal development of the central auditory system.     

Simultaneous recording of electrocochleogram and auditory brainstem responses

A method which can record and plot the electrocochleogram (ECochG) and auditory brainstem response (ABR) simultaneously with the same tracing was studied. The results demonstrated that the ECochG waves obtained by our method and that recorded alone were very similar. The -SP/AP values and the latencies of ABR obtained by those two methods had no statistically significant difference. It could help the recognition of ABR waves, particularly wave I. This technique was more beneficial in determination of wave I-V interpeak latencies and in differential diagnosis between cochlear and retro-cochlear lesions.     

An analysis of auditory brainstem responses in infants

Acoustic brainstem responses (ABRs) were recorded from 148 infants from 4 to 60 weeks of age. 28 subjects returned to the laboratory 3 or more times for additional recordings. Filtered clicks of 1, 2, 4 and 8 kHz were presented at two intensities, 30 and 50 dB HL re the average threshold for a group of young adults. Responses to a broadband click, 50 dB nHL, were also recorded. The latencies of waves I, III and V were measured. Wave I latencies for the 8 kHz filtered click showed no change but those for lower frequencies decreased with age. The latency decreases with age were largest for wave V, and, among the filtered clicks, was largest for the responses to 1 kHz. Best-fitting curves were determined for latency vs. age for each filtered click and for the broadband click. Wave V —Wave I latency differences showed that the rostral conduction time for responses to the 8 kHz FC decreased with age and, for the 1 kHz filtered click (50 dB), remained constant. The early development of basal regions in the cochlea is viewed as insuring the delivery of a wide range of frequencies to rostral segments of the auditory system. The limiting feature of maturation is at rostral sites. The immature auditory system appears to be fully capable of transducing low frequency stimuli, but not high frequencies.     

蹄蝠听性脑干诱发电位特点分析

目的对野生蹄蝠进行短纯音（ToneBurst）和短声（Click）诱导听性脑干反应（ABR）分析,对其ABR特点与已有的研究进行比较,分析其中差异,加深我们对回声定位蝙蝠听觉功能的认识。方法捕捉并饲养野生蹄蝠,运用美国TDT公司（Tucker-Davis Technologies）TDT System Ⅲ诱发电位仪对蝙蝠进行短声和短纯音的听阈测定,分析其波形变化规律,确定其短纯音听阈阈值,分析听力图的特点。结果（1）蹄蝠听阈呈“W”形分布,经统计学分析各听阈区段有统计学意义（P〈0．05）。存在2个听敏区：28kHz处为最敏感的第一听敏区,阈值最低可达15dBSPL,平均29.1dBSPL;40kHz附近出现第二个听敏区,阈值最低25dBSPL,平均35．9dBSPL;在12kHz～64kHz听阈不超过55．9dBSPL。（2）短声引出的蹄蝠ABR可见4个相对稳定的波峰：波I的潜伏期为1．26ms：波Ⅱ较高且尖,潜伏期为1．94ms;波Ⅲ相对稳定,潜伏期为2．47ms;波Ⅴ潜伏期为3．40ms。随着短声强度的上升,在20～80dBSPL声强范围,各个波振幅逐渐增大、潜伏期缓慢缩短。（3）短纯音引出的蹄蝠ABR各波随刺激频率的提高而潜伏期缓慢地缩短,在64kHz以上潜伏期又逐渐延长;在28kHz、80dBSPL条件下,各波潜伏期分别为I波1．74ms,Ⅱ波2．72ms,Ⅲ波3．60ms,Ⅳ波4．58ms,Ⅴ波5．76ms。频率28kHz、声强在45～100dBSPL范围内上升时,主波振幅逐渐增大;但在部分蝙蝠出现主波振幅在达到最大后,随着声强的上升．振幅逐渐减小。（4）在高声强诱发下,短纯音和短声诱发的ABR均可见Ⅰ波分化为2个波峰,Ⅰa和Ⅰb波。（5）越接近敏感频率,ABR波形就越典型,振幅越大。结论（1）蹄蝠听闯呈“W”形分布,类似我们已知的其他回声定位蝙蝠,存在2个听敏区：28kHz处达到最敏感的第一听敏区,40kHz附近出现第二个昕敏区,在12kHz。64kHz听阈不超过55．9dBSPL。（2）从蹄蝠主波与声强、频率的关系可以看出,蝙蝠主波振幅与声强存在一定的正相关。随着接近其敏感听觉频率,波形逐渐变得更为典型,波幅也愈来愈高,反应阈值愈来愈低。但部分蹄蝠在声强高于80dBSPL时,出现振幅随声强增加而下降的趋势,提示可能与中枢某种调节性抑制有关。（3）在高声强诱发下,蹄蝠ABR可以看到Ⅰ波分化为2个波峰,Ⅰa和Ⅰb波,这可能与蝙蝠耳蜗的某些特化结构的“听黄斑”相关。     

Gender effects in auditory brainstem responses to air- and bone-conducted clicks in neonates.

Examinations of gender differences in auditory brainstem response (ABR) wave V latencies and thresholds to air- and bone-conducted clicks were undertaken with neonates. Two hundred and two full-term neonates participated (i.e., 103 males and 99 females). Wave V latency measures for air- and bone-conducted click stimuli of 30, 45, and 60 dB nHL and 15 and 30 dB nHL, respectively, and thresholds to air- and bone-conducted clicks were determined. Female newborns displayed statistically significant shorter wave V latencies than male newborns for air-conducted click stimuli (i.e., approximately 0.2-0.3 ms; P=.0016). There were no significant gender differences in wave V latencies to bone-conducted click stimuli (P=.11). With respect to ABR thresholds, no statistically significant differences were observed for either air-conducted clicks (P=.054) or bone-conducted clicks (P=.18). Educational objectives: As a result of this activity, the participant will be able to (1) describe gender differences in ABR wave V latencies and thresholds to air- and bone-conducted clicks with neonates and (2) summarize possible explanations for observed gender differences in ABR wave V latencies and thresholds to air- and bone-conducted clicks with neonates.     

Tuning of the auditory brainstem OFF responses is complementary to tuning of the auditory brainstem ON response

Continuous masking studies show a complementary pattern of effects on the auditory brainstem responses (ABRs) which are generated by the onset and by the offset of a midfrequency tone. The masking profiles of the two responses are almost opposite with a probe stimulus frequency of 32 kHz (16-32 kHz is the midfrequency region for the CBA/J mouse). The Offset and Onset ABR tuning curves (TCs) also reveal very different properties at the midfrequencies of 16, 20, 24 and 32 kHz. The Offset TC is exquisitely sensitive to masking by very low intensity stimuli at a narrow range of frequencies which are lower than the probe stimulus frequency. Continuous masking produces a well-tuned low frequency tip to the Offset TC. For Offset TCs generated in response to midfrequency tones, the Q+10 dB of this tip averages 8.3. Masking at this low frequency tip of the Offset TC has no observable effect on the Onset ABR. The Offset ABR is also sensitive to masking by a narrow range of frequencies which are higher than the probe stimulus frequency. This occurs at an intensity which also has no observable effect on the Onset ABR. The Q+10 dB of this high frequency tip averages 9.2. The average frequencies where these Offset TC tips occur fit the cubic difference formula (2f1-f2), which describes a distortion product of two-tone suppression. At low probe stimulus frequencies, there is only a high frequency Offset TC tip; at high stimulus frequencies, only a low frequency tip. The high frequency tip has a higher threshold and appears more susceptible to metabolic disturbance. The Offset ABR TC also has a peak which corresponds to the probe stimulus frequency. Continuous masking with the stimulus frequency produces nonmonotonic enhancement of the Offset ABR, while it simultaneously reduces the magnitude of the Onset ABR. The tuning of this Offset TC peak (measured as Q-10 dB) is almost always much sharper than the corresponding Onset TC tip in the same mouse. These values for midfrequency stimuli average 6.2 for the Onset, and 13.6 for the Offset TCs. This fine tuning of the Offset TC at the probe stimulus frequency occurs at SPLs from 50 to more than 90 dB.     

Frequency specificity of the auditory brainstem responses in the cat

The auditory brainstem responses evoked by click, noise-burst and tone-bursts have been recorded in the cat, and octave-wide derived bands obtained at 20 and 50 dB RL intensity levels. At near-threshold intensity both the 2 and 4 kHz tone-bursts are frequency specific, while the click and noise-burst ABR contain no contributions below 2 kHz. The principal contribution to the 1 kHz ABR comes from the 2-4 kHz band, while at 0.5 kHz almost the entire response is generated basally. Higher stimulus intensity produces a spread of activity into other bands. Low frequency cochlear function cannot be assessed by this technique.     

Progressive deterioration of central components of auditory brainstem responses during postnatal development of the myelin mutant taiep rat

Auditory brainstem responses (ABRs) were evaluated during the postnatal development (P10-P180) of taiep rats, neurological mutants characterized by early abnormal myelin development and subsequent demyelination of the CNS. The disorder is produced by an autosomal recessive mutation trait that affects the oligodendrocytes but not the Schwann cells. After onset of ABRs (P12-P14), taiep rats and their nonaffected heterozygous littermates that served as controls showed a similar pattern of maturation for wave I. The central waves (In-IV) showed significantly longer latencies in the mutants. By P60-P180, the later waves (III and IV) were frequently difficult to discern. From the onset of ABRs, the interpeak latency I-IV, corresponding to the central conduction time (CCT) of the auditory pathway, showed in taiep rats significantly longer values than controls. After an initial reduction, proportional to that of control rats, the CCT value increased progressively during the second month of the mutants' lives. The electrophysiological results of the present study strongly support the hypothesis that mutation in the taiep rat impairs neuromaturation of the central auditory pathway in the brainstem by affecting the myelination process in the CNS.     

Beneficial auditory and cognitive effects of auditory brainstem implantation in children

CONCLUSION: This preliminary study demonstrates the development of hearing ability and shows that there is a significant improvement in some cognitive parameters related to selective visual/spatial attention and to fluid or multisensory reasoning, in children fitted with auditory brainstem implantation (ABI). The improvement in cognitive paramenters is due to several factors, among which there is certainly, as demonstrated in the literature on a cochlear implants (CIs), the activation of the auditory sensory canal, which was previously absent. The findings of the present study indicate that children with cochlear or cochlear nerve abnormalities with associated cognitive deficits should not be excluded from ABI implantation. OBJECTIVES: The indications for ABI have been extended over the last 10 years to adults with non-tumoral (NT) cochlear or cochlear nerve abnormalities that cannot benefit from CI. We demonstrated that the ABI with surface electrodes may provide sufficient stimulation of the central auditory system in adults for open set speech recognition. These favourable results motivated us to extend ABI indications to children with profound hearing loss who were not candidates for a CI. This study investigated the performances of young deaf children undergoing ABI, in terms of their auditory perceptual development and their non-verbal cognitive abilities. PATIENTS AND METHODS: In our department from 2000 to 2006, 24 children aged 14 months to 16 years received an ABI for different tumour and non-tumour diseases. Two children had NF2 tumours. Eighteen children had bilateral cochlear nerve aplasia. In this group, nine children had associated cochlear malformations, two had unilateral facial nerve agenesia and two had combined microtia, aural atresia and middle ear malformations. Four of these children had previously been fitted elsewhere with a CI with no auditory results. One child had bilateral incomplete cochlear partition (type II); one child, who had previously been fitted unsuccessfully elsewhere with a CI, had auditory neuropathy; one child showed total cochlear ossification bilaterally due to meningitis; and one child had profound hearing loss with cochlear fractures after a head injury. Twelve of these children had multiple associated psychomotor handicaps. The retrosigmoid approach was used in all children. Intraoperative electrical auditory brainstem responses (EABRs) and postoperative EABRs and electrical middle latency responses (EMLRs) were performed. Perceptual auditory abilities were evaluated with the Evaluation of Auditory Responses to Speech (EARS) battery - the Listening Progress Profile (LIP), the Meaningful Auditory Integration Scale (MAIS), the Meaningful Use of Speech Scale (MUSS) - and the Category of Auditory Performance (CAP). Cognitive evaluation was performed on seven children using the Leiter International Performance Scale - Revised (LIPS-R) test with the following subtests: Figure ground, Form completion, Sequential order and Repeated pattern. RESULTS: No postoperative complications were observed. All children consistently used their devices for >75% of waking hours and had environmental sound awareness and utterance of words and simple sentences. Their CAP scores ranged from 1 to 7 (average =4); with MAIS they scored 2-97.5% (average =38%); MUSS scores ranged from 5 to 100% (average =49%) and LIP scores from 5 to 100% (average =45%). Owing to associated disabilities, 12 children were given other therapies (e.g. physical therapy and counselling) in addition to speech and aural rehabilitation therapy. Scores for two of the four subtests of LIPS-R in this study increased significantly during the first year of auditory brainstem implant use in all seven children selected for cognitive evaluation.     

Comparative study of middle-latency responses and auditory brainstem responses in elderly subjects

Auditory senescence is studied through an electrophysiological investigation of the brainstem, midbrain and thalamocortical tracts of auditory pathways. For this purpose, comparative electrophysiologic studies were carried out by recording middle-latency responses (MLR) and auditory brainstem responses (ABR) in elderly subjects in the 7th-8th and 9th decades of life and in a control group consisting of young subjects in the 3rd decade of life. All these subjects were free of otological, neurological, vascular and metabolic pathologic states. In elderly subjects, the statistical analysis of the results, especially of MLRs, showed a deterioration in the progression of information from the periphery to the center due to changes in morphology, increased latency, reduced amplitude and poorer reproducibility. Furthermore, a different behavior was noticed in females versus males. Indeed, the shorter latency of evoked potentials in the female control group was remarkably reduced in the elderly subjects. MLRs scan a wide tract of auditory pathways and give evident results even by adopting a juxtaliminal stimulation; therefore, they are a more complete and sensitive test than ABRs for the study of involutional processes.     

Beneficial auditory and cognitive effects of auditory brainstem implantation in children

Conclusion: This preliminary study demonstrates the development of hearing ability and shows that there is a significant improvement in some cognitive parameters related to selective visual/spatial attention and to fluid or multisensory reasoning, in children fitted with auditory brainstem implantation (ABI). The improvement in cognitive paramenters is due to several factors, among which there is certainly, as demonstrated in the literature on a cochlear implants (CIs), the activation of the auditory sensory canal, which was previously absent. The findings of the present study indicate that children with cochlear or cochlear nerve abnormalities with associated cognitive deficits should not be excluded from ABI implantation. Objectives: The indications for ABI have been extended over the last 10 years to adults with non-tumoral (NT) cochlear or cochlear nerve abnormalities that cannot benefit from CI. We demonstrated that the ABI with surface electrodes may provide sufficient stimulation of the central auditory system in adults for open set speech recognition. These favourable results motivated us to extend ABI indications to children with profound hearing loss who were not candidates for a CI. This study investigated the performances of young deaf children undergoing ABI, in terms of their auditory perceptual development and their non-verbal cognitive abilities. Patients and methods: In our department from 2000 to 2006, 24 children aged 14 months to 16 years received an ABI for different tumour and non-tumour diseases. Two children had NF2 tumours. Eighteen children had bilateral cochlear nerve aplasia. In this group, nine children had associated cochlear malformations, two had unilateral facial nerve agenesia and two had combined microtia, aural atresia and middle ear malformations. Four of these children had previously been fitted elsewhere with a CI with no auditory results. One child had bilateral incomplete cochlear partition (type II); one child, who had previously been fitted unsuccessfully elsewhere with a CI, had auditory neuropathy; one child showed total cochlear ossification bilaterally due to meningitis; and one child had profound hearing loss with cochlear fractures after a head injury. Twelve of these children had multiple associated psychomotor handicaps. The retrosigmoid approach was used in all children. Intraoperative electrical auditory brainstem responses (EABRs) and postoperative EABRs and electrical middle latency responses (EMLRs) were performed. Perceptual auditory abilities were evaluated with the Evaluation of Auditory Responses to Speech (EARS) battery – the Listening Progress Profile (LIP), the Meaningful Auditory Integration Scale (MAIS), the Meaningful Use of Speech Scale (MUSS) – and the Category of Auditory Performance (CAP). Cognitive evaluation was performed on seven children using the Leiter International Performance Scale – Revised (LIPS-R) test with the following subtests: Figure ground, Form completion, Sequential order and Repeated pattern. Results: No postoperative complications were observed. All children consistently used their devices for >75% of waking hours and had environmental sound awareness and utterance of words and simple sentences. Their CAP scores ranged from 1 to 7 (average =4); with MAIS they scored 2–97.5% (average =38%); MUSS scores ranged from 5 to 100% (average =49%) and LIP scores from 5 to 100% (average =45%). Owing to associated disabilities, 12 children were given other therapies (e.g. physical therapy and counselling) in addition to speech and aural rehabilitation therapy. Scores for two of the four subtests of LIPS-R in this study increased significantly during the first year of auditory brainstem implant use in all seven children selected for cognitive evaluation.