Variables affecting the auditory brainstem response: audiogram, age, gender and head size

Correlations between the ABR (auditory brainstem response) and the variables of hearing loss, gender, head size and age were determined in simple and multiple regression analyses in 334 ears. The stepwise multiple regression analyses for waves I, III and V of the ABR was used to determine the relative importance of the variables. Regression equations were calculated for the latency of each wave. Wave I latency for all subjects is best predicted by hearing threshold at 8 kHz, gender and age, in that order. Wave III latency depends upon hearing threshold at 4 kHz, age and gender. The latency of wave V is best predicted by gender, age and head diameter with threshold at 4 kHz being of minor importance. The I-V interval depends upon head diameter and threshold at 8 and 4 kHz with age of minor importance. Hearing loss at 8 kHz would shorten the I-V interval, while a loss at 4 kHz would be expected to lengthen the interval. Correlations of these variables with the amplitude of I, III and V are also described. Latency and amplitude are correlated with different subject variables suggesting differences in their generation.     

Effects of gender and head size on the auditory brainstem response

Fifty audiologically normal young adults, 25 men and 25 women, were submitted to the auditory brainstem response (ABR) test. The mean latencies of the waves I, II, III, IV and V and the interpeak latencies (IPLs) I-III, I-V and III-V were calculated and compared to the normative values published by other groups. We have observed a great similarity among these values, specially in the interpeak latencies. The latencies of the principal ABR parameters were compared between the sexes showing significant differences in all the waves, particularly in the wave V. No significant correlations were found among the values when the head size and the ABR principal components latencies were confronted.     

Relationship between auditory brainstem response waveform and head size

The relationship between the head size and the latency and amplitude of the auditory brainstem response (ABR) was investigated in 60 normal-hearing adults (30 males and 30 females). We found a strong positive correlation between the latency of ABR waves and the head size and a strong negative correlation surfaced between the ABR amplitude and head size. These results indicate that the head size is one of the most important factors influencing the waveform of the ABR.     

Relationship between head size and latency of the auditory brainstem response

This investigation examines the relationship between the head size of 22 normally hearing individuals and the latency of their respective auditory brainstem responses (ABR). The absolute latency of wave V and the I-V interpeak interval were examined in 12 female and 10 male subjects with varying head sizes. Strong positive correlations were obtained between head size and the latency of both wave V and the I-V interpeak interval. The evidence suggests that this relationship is based upon subject differences in brain size which is reflected in head size. Head size appears to be an important source of intersubject variability which should be considered in order to increase the clinical usefulness of the ABR.     

Correlations between various measures of head size and auditory brainstem response latencies

The literature is mixed concerning the degree to which between-subject variance in the latencies of the auditory brainstem response (ABR) relates to differences in the length of the auditory pathway. Most investigations have used one of several measures of head size to indirectly index brain size and neural pathway length. While some studies have found a positive correlation between head size and the latencies of the ABR, others have reported little or no relationship. We hypothesized that the differences between studies result from differences in the head dimensions measured, the precision of measurement technique, and issues of sampling. We therefore decided to use the International 10-20 system of electrode placement to provide reproducible skull benchmarks on which to base head size measures, to obtain measures of head size via two procedures, and to control external variables that might influence the ABR. The results show that head size has a moderate positive influence on the latencies of the ABR given precise head size measures.     

Analysis of gender differences in the auditory brainstem response

This study examined the effects of hormones, head size, and oral temperatures on latencies and amplitudes of the auditory brainstem response in 10 young women, 10 young men, and 5 postmenopausal women. Significant gender differences between men's and women's auditory brainstem responses were confirmed. Men showed longer latencies and smaller amplitudes than women. Results showed that oral temperature has little effect on auditory brainstem response latencies and amplitudes. Head size affects waves III, V, and the amplitude of wave V, but is not entirely responsible for the gender latency difference. By examining young women with normal monthly hormonal cycles, significant changes in the absolute latencies of wave V were observed. These changes were correlated with hormonal changes as measured from venous blood samples. It was concluded that the etiology of the gender difference is a combination of hormonal and head-size differences.     

The importance of pre-analysis windowing on auditory brainstem response fast Fourier transform analysis

Analysis of auditory brainstem response (ABR) frequency content using fast Fourier transform (FFT) analysis has been used to improve ABR sensitivity and specificity as a diagnostic/site of lesion assessment tool, to improve our understanding of ABR components, and to guide ABR stimulus and recording parameter settings. Threatening this success, however, is the literature's poor control of pre-FFT windowing of the ABR prior to ABR FFT analysis. This study examined the significance of using no (NW), vs Blackman (BW), vs modified Blackman (MBW) pre-FFT windows on the FFT analysis of ABRs recorded from normal subjects. Pre-FFT windowing was shown to significantly reduce (p < 0.00005) ABR FFT magnitudes, but not frequencies, with BW causing greater reductions than MBW. The high significance of these results shows that choice of pre-FFT window is critical in any ABR FFT analysis.     

The auditory steady-state response: comparisons with the auditory brainstem response

Two studies are reported in which the threshold estimates from auditory steady-state response (ASSR) tests are compared to those of click- or toneburst-evoked auditory brainstem responses (ABRs). The first, a retrospective review of 51 cases, demonstrated that both the click-evoked ABR and the ASSR threshold estimates in infants and children could be used to predict the pure-tone threshold. The second, a prospective study of normal-hearing adults, provided evidence that the toneburst-evoked ABR and the modulated tone-evoked ASSR thresholds were similar when both were detected with an automatic detection algorithm and that threshold estimates varied with frequency, stimulus rate, and detection method. The lowest thresholds were obtained with visual detection of the ABR. The studies illustrate that ASSRs can be used to estimate pure-tone threshold in infants and children at risk for hearing loss and also in normal-hearing adults.     

正常气骨导听性脑干反应及其应用

［摘要］目的：研究骨导听性脑干反应(ABR)的波形特点及正常的气、骨导ABR Ⅴ波潜伏期-强度曲线及相应的反应阈值,为临床气导ABR（AC ABR）和骨导ABR(BC ABR)的联合应用提供参考依据。方法：利用Nicolet spirit型诱发电位仪、EAR 3A插入式耳机和Radioear B 71骨振动器对一组听力正常年轻人（男32耳、女24耳）进行短声气骨导ABR测试,并观察对侧给予白噪声掩蔽对BC ABR阈值及潜伏期的影响。结果：气骨导ABR相应强度下波形相似波Ⅴ潜伏期－强度曲线表明,随着刺激强度逐渐减低,潜伏期逐渐延长。骨导Click的潜伏期要比气导Click潜伏期延长的程度大,BC ABR反应阈比气导ABR高。对侧70?dBSPL以下强度宽带噪声的使用对BC ABR阈值及阈上10?dB强度下波Ⅴ潜伏期均无显著影响（P＞0.05）。结论：(1) BC ABR波形特点与相应刺激强度的AC ABR极为相似。BC ABR与AC ABR潜伏期-强度函数曲线可望联合用于传导障碍及其程度的评估;(2) 骨导行为的听阈水平超过40?dBHL时,BC ABR难以引出,对其结果的解释应持慎重态度;(3) 骨导ABR测试时常规加对侧噪声掩蔽,但掩蔽声强度不应超过60?dB。     

Influence of menopause on the auditory brainstem response

Auditory brainstem response (ABR) wave latency, interpeak interval and amplitude as a function of intensity were measured in 40 subjects divided into equal groups of postmenopausal females, age-matched males and young adults of both sexes. The results illustrate that age and gender play a significant role in ABR wave latency and amplitude. A larger age effect occurred for the female subjects. While this does not dispute an anatomical explanation for the gender effect in ABR, hormonal changes accompanying menopause may also account for some of the gender differences noted in ABR.     

Presbyacusis and the auditory brainstem response.

Age-related hearing loss (ARHL or presbyacusis) is an increasingly common form of sensorineural hearing loss (SNHL) as a result of changing demographics, and the auditory brainstem response (ABR) is a common experimental and clinical tool in audiology and neurology. Some of the changes that occur in the aging auditory system may significantly influence the interpretation of the ABR in comparison to the ABRs of younger adults. The approach of this review will be to integrate physiological and histopathological data from human and animal studies to provide a better understanding of the array of age-related changes in the ABR and to determine how age-related changes in the auditory system may influence how the ABR should be interpreted in presbyacusis. Data will be described in terms of thresholds, latencies, and amplitudes, as well as more complex auditory functions such as masking and temporal processing. Included in the review of data will be an attempt to differentiate between age-related effects that may strictly be due to threshold elevation from those that may be due to the aging process.     

脑干肿瘤切除术中的听性脑干反应分析

目的　探索脑干肿瘤手术中听性脑干反应（ａｕｄｉｔｏｒｙ ｂｒａｉｎｓｔｅｍ ｒｅｓｐｏｎｓｅ,ＡＢＲ） 变化规律及其监护作用。方法　对５ 例脑干肿瘤手术患者,从术前、术中至术后进行了ＡＢＲ的动态观察,对术中监护记录的４００ 余份ＡＢＲ的潜伏期、振幅和波形分化的资料进行分析和统计学处理。结果　术中牵拉、分离、挤压均可引起ＡＢＲⅠ、Ⅲ和Ⅴ波潜伏期延长,振幅降低,波形分化差等改变,其中３ 例动态变化指标好,呈可逆性变化,均康复出院。另２ 例术后潜伏期持续延长、波形分化差,动态变化指标差,呈不可逆性变化,术后１ 例死亡,１ 例未苏醒。析因分析显示：手术操作对听性脑干诱发电位的影响有显著性意义（ 方差分析,Ｐ＜ ０．０１） 。结论　在脑干肿瘤手术中,ＡＢＲ能敏感地反映脑干功能,潜伏期、振幅、波形及其动态变化均是术中可靠的观察指标。     

脑性瘫痪患儿听性脑干反应及多频稳态听性反应分析

目的：通过听性脑干诱发反应（ABR）及听性稳态反应（ASSR）分析，探讨脑性瘫痪（脑瘫）患儿的听力障碍及脑干听通道功能变化。方法：采用美国GSIAudera听性脑干反应及听性稳态诱发电位测试仪，测试脑瘫患儿52例104耳。对照组为同龄健康儿童19例38耳。结果：脑瘫组患儿的ABR各波潜伏期及峰间潜伏期均较对照组明显延长；脑瘫组ASSR结果以轻度低频听力损失为著，并且各频率听力损失的平均值非常接近。结论：ABR和ASSR同时应用，为脑瘫患儿听力损失进行定性定量诊断提供了客观的测试方法。     

脑干肿瘤切除术中的听性脑干反应分析

目的 探索脑干肿瘤手术中听性脑干反应（ＡＢＲ）变化规律及其监护作用。方法 对５例脑干肿瘤手术患者,从术前、术中至术后进行了ＡＢＲ的动态观察,对术中监护记录的４００余份ＡＢＲ的潜伏期、振幅和波形分化的资料进行分析和统计学处理。结果 术中牵拉、分离、挤压均可引起ＡＢＲⅠ、Ⅲ和Ｖ波潜伏期延长,振幅降低,波形分化差等改变,其中３例动态变化指标好,呈可逆性变化,均康复出院。另２例术后潜伏期持续延长、波形分化     

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

Recently, auditory steady-state responses (ASSRs) have been proposed as an alternative to the auditory brainstem response (ABR) for threshold estimation. The goal of this study was to investigate the degree to which ASSR thresholds correlate with ABR thresholds for a group of sedated children with a range of hearing losses. Thirty-two children from the University of Iowa Hospitals and Clinics ranging in age from 2 months to 3 years and presenting with a range of ABR thresholds participated. Strong correlations were found between the 2000-Hz ASSR thresholds and click ABR thresholds (r = .96), the average of the 2000- and 4000-Hz ASSR thresholds and click ABR thresholds (r = .97), and the 500-Hz ASSR and 500-Hz toneburst ABR thresholds (r = .86). Additionally, it was possible to measure ASSR thresholds for several children with hearing loss that was great enough to result in no ABR at the limits of the equipment. The results of this study indicate that the ASSR may provide a reasonable alternative to the ABR for estimating audiometric thresholds in very young children.     

窒息状态下ABR及其脑干功能的实验研究

目的 通过观察豚鼠在窒息状态下ABR电位变化及其脑干功能的自然转归，探讨听觉通路损伤程度和临床意义。方法。听觉诱发电位仪和心电搏氧饱和度监测仪检测3组不同窒息时限的豚鼠的ABR各波潜伏期及波间期，氧饱和度（SO2）及心率（HR）等。结果 波V最易受缺氧的影响，波Ⅲ次之，波I最后消失和最早恢复，窒息时限影响脑干功能，导致1组和2组的各波潜伏期和波间期差有统计学上的意义。窒息时间超过5min30s。实验豚鼠均死亡。结论 ABR可作为窒息状态下判断脑功能及脑死亡的重要辅助指标。应争分夺秒抢救窒息并及时处理心脑的损害。     

The bifrequency binaural interaction component of the auditory brainstem response

The binaural interaction component of the auditory brainstem response was investigated in three stimulus conditions, 1000-Hz tone pips to both ears, 3000-Hz tone pips to both ears, and 1000-Hz tone pips to the left ear and 3000-Hz tone pips to the right ear. A binaural interaction component was produced in all conditions in which the stimuli were presented in quiet and in broadband noise, suggesting that a frequency separation of 2000 Hz between ears can produce a fused image. Responses to the bifrequency stimuli in noise indicated the peak A of the binaural interaction component is not dependent solely on the slope of wave V because when the noise caused a dissociated binaural wave V, peak A was associated only with the trailing wave V.