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.     

Effects of presbycusis and other types of hearing loss on auditory brainstem responses

Auditory brainstem responses were studied in 373 healthy individuals of various ages and with sensorineural hearing loss of differing degrees. 209 subjects were elderly and had a hearing loss which included a component of presbycusis. The remainder were young or middle-aged with cochlear hearing loss. Altogether 606 ears were tested. The old individuals had generally longer ABR wave latencies than the young subjects. The I-V interpeak latency (IPL) was also prolonged in the older age groups compared with the group of younger individuals, except for subjects with pronounced hearing loss. The results of the study indicate that an age-related dysfunction of the auditory pathway in the brainstem can be present in presbycusis.     

Effects of clinical factors on auditory brainstem responses in patients with asymmetric hearing loss

OBJECTIVE: To evaluate the auditory brainstem responses (ABRs) in patients with asymmetric hearing loss (ASHL). METHODS: Data on 245 patients (men=106; women=139) with ASHL were gathered, retrospectively. Effects of sex, age, stimulation side, and hearing level on ipsilateral ABRs were carried out by multivariate linear regression. RESULTS: Waves III and V latencies were only significantly affected by sex and hearing level but not by age and stimulation side, in patients with ASHL. In addition, wave V latencies were positively correlated with age in men, but not in women; III-V intervals were significantly affected only by sex and age but not by stimulation side or hearing level. CONCLUSION: Effects of clinical factors on ABR were different between patients with ASHL and normal-hearing subjects.     

Influence of myelography on the developmental curve of auditory brainstem responses and hearing loss

Auditory threshold and auditory brainstem response studies were conducted in 50 patients before and after myelography. Analysis of amplitudes and latencies of auditory brainstem measurements demonstrated significant disorders of function of the cochlea and auditory pathway. The Jewett I wave showed a prolongation of latency from 1.92 to 1.98 ms using an average of all repetition rates. The Jewett III wave showed prolongation from 4.01 to 4.14 ms and the Jewett V wave prolongation from 6.01 to 6.16 ms. At the same time average amplitudes for Jewett III and V decreased. In most of the patients these disorders of function were found to be subclinical. However, 12 patients had changes ranging from a subjectively slight hearing loss to an audiometrically defined acute hearing loss. The reasons for these disorders could not be clarified. An open cochlear aqueduct through which perilymph can enter the subarachnoid space, leading to secondary endolymphatic hydrops, was suggested as the cause for the losses found. Changes in brainstem audiometry were also explained by changes in osmolality of inner ear fluids, leading to the development of an endolymphatic hydrops.     

Desynchronisation of auditory steady-state responses related to changes in interaural phase differences: an objective measure of binaural hearing

Objective: Binaural processing can be measured objectively as a desynchronisation of phase-locked neural activity to changes in interaural phase differences (IPDs). This was reported in a magnetoencephalography study for 40?Hz amplitude modulated tones. The goal of this study was to measure this desynchronisation using electroencephalography and explore the outcomes for different modulation frequencies. Design: Auditory steady-state responses (ASSRs) were recorded to pure tones, amplitude modulated at 20, 40 or 80?Hz. IPDs switched between 0 and 180° at fixed time intervals. Study sample: Sixteen young listeners with bilateral normal hearing thresholds (≤25?dB HL at 125–8000?Hz) participated in this study. Results: Significant ASSR phase desynchronisations to IPD changes were detected in 14 out of 16 participants for 40?Hz and in 8, respectively 9, out of 13 participants for 20 and 80?Hz modulators. Desynchronisation and restoration of ASSR phase took place significantly faster for 80?Hz than for 40 and 20?Hz. Conclusions: ASSR desynchronisation to IPD changes was successfully recorded using electroencephalography. It was feasible for 20, 40 and 80?Hz modulators and could be an objective tool to assess processing of changes in binaural information.     

Newborn hearing screening with combined otoacoustic emissions and auditory brainstem responses

Accurate assessment of neonatal hearing screening performance is impossible without knowledge of the true status of hearing, a prohibitive requirement that necessitates a complete diagnostic evaluation on all babies screened. The purpose of this study was to circumvent this limitation by integrating two types of screening measures obtained near simultaneously on every baby. Peripheral auditory function was defined by otoacoustic emission results. A complete diagnostic evaluation was performed on every baby who received a "Refer" outcome for auditory brainstem response screening. The integrated results for auditory brainstem response screening in an unselected group of 300 newborns estimated sensitivity at 100%, specificity at 99.7%, overall referral rate at 2.0%, and a positive predictive value of 83.3%. Conductive loss associated with amniotic fluid in the middle ear can persist several weeks after birth; conductive loss can produce a "Refer" outcome for auditory brainstem response screening; and auditory neuropathy can be detected with screening measures. Prevalence results were consistent with the published literature. The implications of this study are that otoacoustic emissions and auditory brainstem measures provide much more information than either alone and that both are needed for a comprehensive hearing screening program.     

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.     

Evaluation of auditory brainstem responses for hearing screening of high-risk infants

Auditory brainstem responses (ABR) were recorded in 30 normal and 60 high-risk neonates with gestational age between 30 and 45 weeks. The normative data of normal group as regard to age, sex and various parameters of ABR were compared with high-risk group. ABR parameters especially wave V and interwave V-I intervals were significantly prolonged in high-risk infants. An infant was considered to “pass” the ABR test if an identifiable and replicable wave V response was present at 30 dB HL in both ears. All the normal neonates had click thresholds consistent with normal hearing. 12 of the highrisk neonates showed mild to moderate hearing impairment (absent replicable wave V at 30–60 dB HL) and 2 of them showed severe to profound hearing impairment (absent replicable wave V at 70 dB HL). 9 of the “failed” group were reevaluated within 3 months and several times thereafter if the abnormal responses persisted. 2 (3.3%) infants showed persistent hearing loss, which was confirmed later by behavioral audiometry.     

Comparison of auditory steady-state responses and auditory brainstem responses in audiometric assessment of adults with sensorineural hearing loss

Objective

Many of the medico-legal patients who claimed compensation may exaggerate hearing loss that varies in degree, nature, and laterality. The purpose of this study was to investigate whether Auditory Steady-State Response (ASSR) could be used to predict the hearing level of adults, and whether ASSR could become a better testing method than Auditory brainstem response (ABR) in audiometric assessment of adults with sensorineural hearing loss.

Methods

This was a prospective study, which was conducted in a tertiary referral hospital. From January to June 2007, 142 subjects (284 ears) with varying degrees of sensori-neural hearing impairment were included in this study. Four commonly used frequencies (500, 1000, 2000, 4000 Hz) were evaluated. All subjects received pure-tone audiometry, multi-channel ASSR, and ABR tests for threshold measurement. The correlation of pure tone thresholds with ASSR and ABR thresholds were assessed.

Results

Between multi-channel ASSR and pure tone thresholds, a difference of less than 15 dB was found in 71% while a difference of less than 25 dB was found in 89% of patients. The correlation coefficient (r) of multi-channel ASSR and pure tone thresholds were 0.89, 0.95, 0.96, and 0.97 at 500, 1000, 2000, and 4000 Hz, respectively. The strength of the relationship increased with increasing frequency. On the other hand, between ABR and pure-tone thresholds, a difference of less than 15 dB was found in 31%; a difference of less than 25 dB was found in 62% of patients. The r correlation value for ABR and pure tone thresholds was 0.83.

Conclusion

ASSR is a more reliable test for the accurate prediction of auditory thresholds than ABR. It can be a powerful and convenient electro-physiologic examination tool for clinically assessing of adults with sensorineural hearing loss.     

Effects of isoflurane on the auditory brainstem responses and middle latency responses of rats

OBJECTIVE: To evaluate the effects of a volatile anesthetic, isoflurane, on auditory brainstem responses (ABRs) and middle latency responses (MLRs) recorded in rats. MATERIAL AND METHODS: ABRs and MLRs evoked by click stimuli were simultaneously recorded in eight rats in the awake condition and during anesthesia with isoflurane at clinically relevant concentrations. RESULTS: Vertex-recorded ABRs showed a significant increase in the latency of waves I-IV during anesthesia and the latency changes appeared to be significantly related to the isoflurane concentration. The I-IV interval also appeared to be significantly increased in comparison to the awake condition, while minor changes in ABR amplitudes were induced by isoflurane. MLRs, which were recorded by means of epidural electrodes implanted over the auditory cortex, appeared to be attenuated in amplitude and increased in latency during anesthesia. Only latency changes appeared to be significantly related to the isoflurane concentration. Moreover, "bursts" of high amplitude MLRs were observed during anesthesia at each concentration. CONCLUSION: The present findings indicate that both ABR and MLR latencies are increased by isoflurane in a concentration-dependent manner, whilst the anesthetic-induced attenuation in amplitude does not appear to be related to the isoflurane concentration.     

游戏测听与听觉诱发脑干反应评估小儿听力

目的 通过对60例3～6岁感音神经性耳聋小儿听性脑干反应(auditory brainstem response,ABR)与小儿游戏测听(play audiometry,PA)测试结果比较,综合评估小儿听力.方法 选择60例3～6岁门诊患儿,均经声导抗测试及耳声发射测试排除传导性耳聋及听神经病,将60例3～6岁小儿120耳分别进行ABR测试.根据ABR测试结果.选择ABR波V反应阈为50～90 dB nHL的小儿30例为A组,ABR最大输出97 dB nHL未引出波V反应阚的小儿30例为B组;之后两组小儿分别进行游戏测听,将两组的ABR反应阈与游戏测听测试结果进行比较.结果 A组ABR的波V反应阈与小儿游戏测听中2 kHz～4 kHz最小听闻相差均无显著差异:B组ABR最大输出97 dB nHL未引出波V的小儿,游戏测听绝大部分均能获得行为听阈.结论 ABR的波V反应阈与小儿行为测听的高频听阈一致性较好;ABR最大输出97 dB nHL未引出波V的不等于无听力.     

A study of hearing in the elderly using non-invasive electrocochleography and auditory brainstem responses

The auditory brainstem responses exhibited normal interpeak intervals of waves I-III and I-V in a group of 31 elderly people (mean age 82 years), indicating normal conduction through the brainstem. The amplitudes of the waves I, III and V were significantly reduced and the peaks I, III and V showed a delay in latency, reflecting a predominantly lower level of activity in the elderly cochlea. Extratympanic electrocochleography yielded significantly reduced amplitudes of the N1 component of the action potential, summating potential and cochlear microphonics in the elderly compared to the young controls. A heterogeneity of patterns of input/output functions was observed and interpreted as either an absence of recruitment, as partial or as complete recruitment. The findings are in keeping with pathological evidence of severe damage to outer hair cells and complete atrophy of part of the basal coil.     

Utility of auditory steady-state and brainstem responses in age-related hearing loss in rats

Conclusions: The results support the idea that auditory steady-state response (ASSR) is a more accurate test for studying age-related hearing loss (ARHL) in Sprague-Dawley rats. Differences in the rat middle ear may explain the variations of the click properties, with a displacement of the energy toward the 8 and 10 kHz frequencies compared with humans. Objectives: The purpose of this study was to evaluate ARHL in older and younger Sprague-Dawley rats using auditory clicks and tone burst with auditory brainstem response (ABR), in addition to ASSR. Methods: This was a prospective cohort study with 50 animals divided into 5 groups based on their age in months. A total of 100 registers were elicited from each one of the 3 auditory measurements systems in an electrically shielded, double-walled, sound-treated cabin. Nine frequencies, from 0.5 to 16 kHz were analyzed with the auditory steady-state response and compared with the results elicited by the clicks and tone-burst ABR. Results: Comparisons between the different frequencies showed lower thresholds in those frequencies below 2 kHz, independently of their age in months. The ARHL was detected by each one of the three auditory measurement systems, but with lower thresholds with the ASSR test. Finally, auditory clicks showed better correlations with 8 and 10 kHz elicited by ASSR, which was different to what was expected, based on human studies.     

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.     

多频稳态诱发电位和听性脑干反应对感音神经性聋儿童客观听阈的评估

目的比较多频稳态诱发电位(MASSR)与短纯音听性脑干反应(Tb-ABR)对感音神经性聋儿童客观听阈的评估。方法对37名感音神经性聋儿童分别测试MASSR反应阈、Tb-ABR反应阈和行为听阈,参照行为听阈,比较MASSR反应阈和Tb ABR反应阈对行为听阈评估的准确性。结果MASSR反应阈、Tb-ABR反应阈和行为听阈之间均有较高的相关性。二者在频率为2、4kHz时,对行为听阈的评估具有相似的准确性;但在频率为0.5、1kHz时,MASSR的准确性较Tb ABR的准确性高。结论MASSR和Tb-ABR均可用作感音神经性聋儿童言语频率客观听阈的评估,但MASSR在低频(0.5、1kHz)时较Tb-ABR的准确性高。     

Wave V interaural latency differences as a function of asymmetry in 2,000-4,000 Hz hearing sensitivity

Interaural latency differences for wave V (IT5) were measured for 406 patients having cochlear hearing loss and for 36 patients with VIIIth nerve tumors. The incidence of IT5 values exceeding 0.2, 0.3, and 0.4 msec was plotted as a function of the degree of asymmetry in hearing sensitivity for 2,000-4,000 Hz. In general, the patients with cochlear hearing loss and the greatest degree of hearing asymmetry yielded IT5 values that exceeded 0.2, 0.3, or 0.4 msec more frequently than patients with more symmetric hearing losses, and this trend was apparent for all degrees of hearing loss. For the VIIIth nerve tumor patients, IT5 data were scattered widely regardless of symmetry or asymmetry of hearing sensitivity. The false-negative rate was 8% when IT5 was greater than 0.4 msec.     

Neonatal hearing screening using the auditory brainstem response

A targeted screen of babies at risk of having a sensorineural hearing loss (SNHL) using the auditory brainstem response has been in place since 1987 in Bradford and Airedale. The aims of this paper were to ascertain what proportion of a 4-year cohort of children with SNHL should have been identified by the programme; was identified by the programme; and the reasons for failing when children were missed. The cohort of 49 children had moderate to profound SNHL (> 50 dB) and were born between 1 April 1991 and 31 March 1995. Although 92% had at risk factors (higher than in other series), 80% was the maximum that could have been prospectively detected by the programme and only 37% were actually diagnosed as a result of the screening programme. Apart from a generalised under-recruitment, children with risk factors arising because of in utero, perinatal and postnatal events (as opposed to family history, craniofacial abnormalities and syndromes) tended to be missed (P < 0.01). The overall yield of the screening programme was 0.5/1000/year. While the yield of a universal neonatal screening programme based on otoacoustic emissions should be double this, a targeted infant distraction test later in infancy will be an essential backup. Improved liaison with paediatricians in particular as well as simplification of the referral criteria should improve targeting children at risk.     

Influence of age, sex, and hearing loss on auditory brain stem response (ABR) latencies

In a previous paper, the hypothesis was established that the shorter auditory brain stem response (ABR) latencies in females, in comparison with males, can be explained solely by the age dependence of the latencies, which is more pronounced in males than in females. According to this concept, ABR latencies in male and female babies are identical but diverge increasingly with increasing age. A multiple regression analysis on considerably enlarged male and female groups has now confirmed the hypothesis as to the differing age dependence in males and females. But the results also show that the male/female ABR latency differences cannot be explained solely by these differences in age dependence. An additional factor has to be taken into account, for which the male/female difference in auditory pathway length is a plausible explanation.     

Discrepancy between auditory brainstem responses, auditory steady-state responses, and auditory behavior in two patients with Pelizaeus-Merzbacher disease

We reported two cases of Pelizaeus-Merzbacher disease. Both cases visited our hospital manifesting horizontal nystagmoid movements present from birth, and delayed motor development. Magnetic resonance imaging of the brain showed diffuse dysmyelination of the cerebral white matter, and auditory brainstem response showed waves I and II but absence of all subsequent components. Conditioned orientation reflex (COR) audiometry showed poor reactions in an infantile case whose development was severely retarded, and who spoke no meaningful words. Auditory steady-state response (ASSR) was a helpful tool for identifying her auditory ability; thereafter, her communication skills improved naturally. The other case was mildly developmentally retarded, and the results of COR audiometry and ASSR were considered the same level. The discrepancy between results of these hearing tests may arise under the influence of developmental level of the case.