Long latency auditory event-related potentials from children with auditory processing disorders

The purpose of this study was to evaluate auditory event-related potentials, and related long latency components, in children with auditory processing disorders, and to compare these results with a normal group matched for age, intelligence, and gender. Results showed a significant latency increase for the N1, P2, and P3 components in the processing disordered group. Furthermore, the interpeak latency interval P2-P3 was significantly longer in the clinical group. In terms of amplitude measures, only P3 amplitude differed significantly between groups. These results suggest that the long latency potentials may be useful in the assessment of children with processing disorders.     

Habituation deficit in auditory event-related potentials in tinnitus complainers

According to Hallam's habituation theory of tinnitus, most of the suffering caused by tinnitus is due to difficulties in habituation to the perceived tinnitus sound. Thus tinnitus complainers are assumed to display a less pronounced habituation as compared to tinnitus non-complainers. In the present study, an experimental test of this theory was undertaken using event-related potentials (ERPs) as indicators of habituation to exogenously administered tone pips. In 22 patients (10 tinnitus complainers and 12 tinnitus non-complainers) and 10 healthy controls, the habituation of ERPs to series of auditory stimuli across four consecutive trials was studied. Diminuition of the N(1) and P(2) amplitudes of the ERPs was taken to measure the habituation process across the trials. Tinnitus complainers showed a less distinct habituation of the N(1)-P(2) amplitude difference (vertex potential) compared to tinnitus non-complainers. The results are in accordance with Hallam's theory and support the notion that patients with a severe tinnitus fail to properly habituate to auditory stimuli.     

Effects of low-pass noise masking on auditory event-related potentials to speech

OBJECTIVE: This study investigated the effects of decreased audibility in low-frequency spectral regions, produced by low-pass noise masking, on cortical event-related potentials (ERPs) to the speech sounds /ba/ and /da/. DESIGN: The speech sounds were presented to normal-hearing adults (N = 10) at 65- and 80-dB peak-to-peak equivalent SPL while they were engaged in an active condition (pressing a button to deviant sounds) and a passive condition (ignoring the stimuli and reading a book). Broadband masking noise was simultaneously presented at an intensity sufficient to mask the response to the 65-dB speech sounds and subsequently low-pass filtered. The conditions were quiet (no masking), low-pass noise cutoff frequencies of 250, 500, 1000, 2000, and 4000 Hz, and broadband noise. RESULTS: As the cutoff frequency of the low-pass noise masker was raised, ERP latencies increased and amplitudes decreased. The low-pass noise affected N1 differently than the other ERP or behavioral measures, particularly for responses to 80-dB speech stimuli. N1 showed a smaller decrease in amplitude and a smaller increase in latency compared with the other measures. Further, the cutoff frequency where changes first occurred was different for N1. For 80-dB stimuli, N1 amplitudes showed significant changes when the low-pass noise masker cutoff was raised to 4000 Hz. In contrast, d', MMN, N2, and P3 amplitudes did not change significantly until the low-pass noise masker was raised to 2000 Hz. N1 latencies showed significant changes when the low-pass noise masker was raised to 1000 Hz, whereas RT, MMN, N2, and P3 latencies did not change significantly until the low-pass noise masker was raised to 2000 Hz. No significant differences in response amplitudes were seen across the hemispheres (electrode sites C3M versus C4M) in quiet, or in masking noise. CONCLUSIONS: These results indicate that decreased audibility, resulting from the masking, affects N1 in a differential manner compared with MMN, N2, P3, and behavioral measures. N1 indexes the presence of audible stimulus energy, being present when speech sounds are audible, whether or not they are discriminable. MMN indexes stimulus discrimination at a pre-attentive level. It was present only when behavioral measures indicated the ability to differentiate the speech sounds. N2 and P3 also were present only when the speech sounds were behaviorally discriminated. N2 and P3 index stimulus discrimination at a conscious level. These cortical ERP in low-pass noise studies provide insight into the changes in brain processes and behavioral performance that occur when audibility is reduced, such as with low frequency hearing loss.     

The role of event-related brain potentials in assessing central auditory processing

The perception of complex acoustic signals such as speech and music depends on the interaction between peripheral and central auditory processing. As information travels from the cochlea to primary and associative auditory cortices, the incoming sound is subjected to increasingly more detailed and refined analysis. These various levels of analyses are thought to include low-level automatic processes that detect, discriminate and group sounds that are similar in physical attributes such as frequency, intensity, and location as well as higher-level schema-driven processes that reflect listeners' experience and knowledge of the auditory environment. In this review, we describe studies that have used event-related brain potentials in investigating the processing of complex acoustic signals (e.g., speech, music). In particular, we examine the role of hearing loss on the neural representation of sound and how cognitive factors and learning can help compensate for perceptual difficulties. The notion of auditory scene analysis is used as a conceptual framework for interpreting and studying the perception of sound.     

相关视觉刺激抑制听觉相关电位研究

目的通过视(口形)-听(声音)联合刺激的事件相关电位(ERP)的研究,结合脑地形图分析,探讨视-听联合刺激的皮层处理相互关系。方法收集正常青年志愿者19名,年龄22-30岁,予行标准刺激(元音[a])和变异刺激(元音[i])的视-听联合刺激及单独视觉、单独听觉刺激ERP检查。比较三种刺激条件下诱出的ERP的差异。结果视-听联合标准刺激能诱发视觉刺激N1波和N2以及听觉刺激在600ms左右出现的正向波(P1波)。视-听联合刺激与单纯视觉刺激诱出的波形一致性较好,潜伏期、波幅均无显著差异。但视-听联合刺激的听觉P1波较单纯听觉刺激P1波的波幅减弱(P=0.04),且脑地形图显示视-听联合刺激的听觉P1波分布向视觉中枢靠近。结论视觉刺激对同意义听觉反应有抑制作用,且相关视觉刺激能使听觉刺激激活的区域向视觉靠近,提示在听觉康复训练过程中,可能避免视觉刺激(唇读)的康复效果更佳,但相关的研究需要进一步的深入。     

Effects of stimulus level on cortical auditory event-related potentials evoked by speech

The effect of stimulus level on cortical auditory event-related potentials (ERPs) evoked by consonant-vowel (CV) contrasts, /ta/, /da/, and /sa/, was investigated. The lowest level at which CVs were discriminated with >95% accuracy was determined for 15 normally hearing adults. ERPs were obtained at 0, 20, and 40 dB SL above this level during active listening. ERP latencies decreased as level increased. P300 amplitude did not vary with CV level or type; however, obligatory ERPs decreased in amplitude as level increased. The effect of level on P300 latency is likely related to the cognitive processing speed needed to perform speech discrimination. Obligatory ERP amplitude results suggest that attention demands vary with level during discrimination of speech features.     

采用不同汉语言语刺激声测试听觉事件相关电位的对比研究

目的:比较不同刺激声(包括纯音、实意字、双音节词和数字)诱发的听觉事件相关电位(auditory e-vent-related potentials,AERP)反应特性,探讨汉语言语声刺激测试中国人AERP的可行性,进一步探讨AERP的产生机制和临床意义。方法:采用纯音和3种不同的汉语言语作为声刺激对37例(70耳)正常青年人进行AERP测试,对波形进行量化评分,比较各种刺激声诱发的AERP潜伏期、幅值及波形评分。结果:汉语言语和纯音均可以记录到典型的AERP波形,其中以刺激声为双音节词最容易记录到,各种刺激声对P3的引出率差异有统计学意义(χ2=0.046,P<0.05)。56耳在各种言语及纯音刺激时均能记录到AERP的波形表明,P3波形量化评分及N2-P3振幅在不同刺激声之间的差异均无统计学意义(均P>0.05),但字和双音节词诱发的AERP波形较数字和纯音平滑,杂波少。数字诱发的P3潜伏期较其他组长,且差异有统计学意义(均P<0.05),而其他组间的P3潜伏期相比较则差异均无统计学意义(均P>0.05)。结论:除纯音和字外,汉语言语的其他形式,如双音节词、数字也符合AERP测试刺激声的要求,可以得到满意的AERP波形,同样适用于中国国民的AERP测试,为言语测试AERP在临床上的进一步推广提供了一种更适合中国国民的测试方法。     

纯音和言语刺激声强度对听觉事件相关电位的影响

目的:探讨分别以纯音和言语作刺激声时声强度对听觉事件相关电位(AERP)的影响.方法:采用不同强度的纯音和言语作为刺激声对正常年青人进行AERP测试,比较纯音和言语诱出典型P300的强度范围,分析不同强度对P300的影响是否同时存在于纯音和言语刺激声.结果:言语刺激声比纯音更容易在40～70 dBSL范围内连续记录到典型波形,差异有统计学意义(P＜0.01).言语或纯音刺激时,强度对P300潜伏期的影响差异均有统计学意义(P＜0.01),在40～70 dBSL范围内潜伏期随强度增加而减小,强度对P300幅值的影响差异均无统计学意义.结论:强度对AERP的影响在纯音和言语刺激时基本相同,但言语得到典型AERP波形的强度范围较纯音宽,其原因可能与言语刺激声包含的信息较纯音刺激声丰富,受试者对汉语言语刺激声较纯音更熟悉有关.     

Classification of passive auditory event-related potentials using discriminant analysis and self-organizing feature maps

Discriminant analysis (DA) and self-organizing feature maps (SOFM) were used to classify passively evoked auditory event-related potentials (ERP) P(1), N(1), P(2) and N(2). Responses from 16 children with severe behavioral auditory perception deficits, 16 children with marked behavioral auditory perception deficits, and 14 controls were examined. Eighteen ERP amplitude parameters were selected for examination of statistical differences between the groups. Different DA methods and SOFM configurations were trained to the values. SOFM had better classification results than DA methods. Subsequently, measures on another 37 subjects that were unknown for the trained SOFM were used to test the reliability of the system. With 10-dimensional vectors, reliable classifications were obtained that matched behavioral auditory perception deficits in 96%, implying central auditory processing disorder (CAPD). The results also support the assumption that CAPD includes a 'non-peripheral' auditory processing deficit.     

Phonetic processing in children with cochlear implants: an auditory event-related potentials study

OBJECTIVES: To investigate the effect of increasing acoustic-phonetic difficulty in children with cochlear implants (CI) by means of auditory event-related potentials (AERPs). DESIGN: AERPs were recorded from a group of ten 9- to 14-year-old prelingually deafened children who exhibited open-set speech recognition, using the Nucleus 22 CI for at least 5 years. AERPs were recorded in sound field while children were performing oddball discrimination tasks with increasing acoustic-phonetic demand. The tasks consisted pairs of naturally produced stimuli that differed by one phonetic feature: vowel place (/ki/ versus/ku/), vowel height (/ki/ versus /ke/), voicing (/ka/ versus /ga/), and place of articulation (/ka/ versus /ta/). Using a repeated measure design, the effect of increasing acoustic-phonetic difficulty on P3 latency, amplitude, and scalp distribution as well as on the simultaneously obtained behavioral measures, performance accuracy, and reaction time was evaluated. RESULTS: AERPs elicited in the range of 350 msec poststimulus onset were contaminated by the CI stimulus artifact, thus enabling reliable identification of the P3 component only. Increasing acoustic-phonetic difficulty was manifested in all measures in a hierarchical manner: P3 latency and reaction time increased, whereas P3 amplitude and performance accuracy decreased. The correlations, however, between behavioral and electrophysiological measures were not significant. Further support for P3 sensitivity to increasing acoustic-phonetic demand was its absence in four of the 10 children, but only in the most difficult place of articulation task. P3 amplitude was maximal at the midline parietal cite, with equal amplitudes over the right and left scalp regardless of side of implant. CONCLUSIONS: The results underscore the significant value of the P3 potential as a sensitive neural index of speech-sound processing in children with CI. The similar hierarchy of acoustic-phonetic demand manifested in both behavioral and electrophysiological measures suggests that speech perception performance relates to neurophysiologic responses at cortical levels of the auditory system. Thus, recording the P3 potential to distinct phonetic contrasts may be useful for studying accessibility and neural encoding at the cortical level in CI recipients.     

Diagnostic significance of the staggered spondaic word test and 40-Hz auditory event-related potentials

This paper discusses the diagnostic value of the staggered spondaic word (SSW) test, the auditory brainstem response (ABR) and the 40-Hz auditory event-related potentials (40-Hz AERP). The results show that upper brainstem lesions consistently produce abnormal 40-Hz auditory event-related potentials (AERP) and acoustic neuromas consistently produce abnormal ABR. If SSW test results are abnormal and the 40-Hz AERP and ABR normal, a temporal lobe lesion must be considered. This study supports the view that the origin of the 40-Hz AERP is at the level of the midbrain or thalamus.     

采用纯音和汉语言语声刺激测试听觉事件相关电位的对比研究

目的 比较纯音和汉语言语声刺激诱发的听觉事件相关电位(auditory event-related potentials,AERP)波形,探讨用汉语言语声刺激测试中国人AERP的可行性.方法 采用汉语言语和纯音作为声刺激对正常青年人(44名,83耳)进行AERP测试,对波形进行评分.比较言语和纯音声刺激诱发的AERP的潜伏期、幅值及波形评分.结果 言语声刺激比纯音更容易记录到典型AERP波形,差异有统计学意义(X2=4.0,P=0.039).分析言语及纯音刺激均记录到的72组AERP波形,言语和纯音刺激诱发的P3的潜伏期、幅值差异均无统计学意义(P>0.05),但言语诱发的AERP波形评分较纯音高(t=6.57,P=0.000).左耳言语刺激诱发的AERP的N2、P3潜伏期短于纯音,差异均有显著统计学意义(前者P=0.002,后者P=0.003),而右耳差异无统计学意义(P>0.05).结论 汉语普通话单词较符合AERP测试的要求和我国日常言语的习惯,汉语言语刺激较纯音可能更适合中国人的AERP测试.     

Assessing binaural/bimodal advantages using auditory event-related potentials in subjects with cochlear implants

Objective

To assess the advantage of binaural and bimodal hearing for subjects with cochlear implant (CI) using auditory event-related potentials as well as speech perception tests.

Subjects and methods

The subjects comprised four binaural CI users (CI/CI group) and eleven bimodal CI users, who wore a hearing aid (HA) contralaterally (CI/HA group). All subjects had used binaural or bimodal fitting for over 6 months. Their speech perception was examined in a quiet environment using monosyllabic words. Late cortical waves were measured while subjects were engaged in an oddball task of 1 kHz frequent and 2 kHz rare tone stimuli. The latencies of event-related potential (N1, N2, P3) were compared for monaural, binaural, and bimodal hearing conditions.

Results

Significantly (p < 0.01, paired t-test) better speech perception for monosyllabic words was found for both binaural and bimodal hearing than monaural hearing. The latency of N1 did not significantly change for either binaural or bimodal hearing. On the other hand, the latency of N2 was significantly (p < 0.01, paired t-test) shorter for binaural and bimodal hearing than for monaural hearing. The latency of P3 was shorter for binaural and bimodal hearing than monaural hearing in all subjects, and the difference was statistically significant in both CI/CI and CI/HA groups (p < 0.01, paired t-test).

Conclusions

Better speech perception was obtained for binaural and bimodal hearing than for monaural hearing in CI subjects. The results obtained in the comparison of P3 latency agreed with that of speech perception. Thus, using bilateral hearing devices is recommended for CI subjects. We also found that event-related potentials were useful as an objective tool to assess the advantage of binaural and bimodal hearing for CI subjects.     

Asymmetry in event-related potentials to simulated auditory motion in children, young adults, and seniors

We studied auditory evoked responses to the apparent movement of a burst of noise in the horizontal plane. Event-related potentials (ERPs) were measured in three groups of participants: children in the age range from 9 to 12 years, young adults in the age range from 18 to 34 years, and seniors in the age range from 65 to 80 years. The topographic distribution of grand-averaged ERP activity was substantially greater over the right hemisphere in children and seniors but slightly greater over the left hemisphere in young adults. This finding may be related to age-related differences in the extent to which judgments of sound movement are based on displacement versus velocity information.     

Auditory event-related potentials and function of the medial olivocochlear efferent system in children with auditory processing disorders

Objective: The objectives were to investigate the function of central auditory pathways and of the medial efferent olivocochlear system (MOCS).

Design: Event-related potentials (ERP) were recorded following the delivery of the stimulus /da/ in quiet and in ipsilateral, contralateral, and binaural noise conditions and correlated to the results of the auditory processing disorders (APD) diagnostic test battery. MOCS function was investigated by adding ipsilateral, contralateral, and binaural noise to transient evoked otoacoustic emission recordings. Auditory brainstem responses and pure tone audiogram were also evaluated.

Study Sample: Nineteen children (7 to 12?years old) with APD were compared with 24 age-matched controls.

Results: Otoacoustic emissions and ABR characteristics did not differ between groups, whereas ERP latencies were significantly longer and of higher amplitudes in APD children than in controls, in both quiet and noise conditions. The MOCS suppression was higher in APD children.

Conclusions: Findings indicate that children with APD present with neural deficiencies in both challenging and nonchallenging environments with an increase in the timing of several central auditory processes correlated to their behavioural performances. Meanwhile, their modulation of the auditory periphery under noisy conditions differs from control children with higher suppression.     

大鼠听觉事件相关电位的反应特性

目的 探讨被动模式下大鼠是否存在听觉事件相关电位（auditory event-related potential,AERP）及其反应特点,建立测试动物AERP的方法.方法 选择正常幼年和成年大鼠为测试对象,麻醉状态下以被动模式进行AERP的测试.比较二组AERP的反应特点,并与被动模式记录的人的AERP进行比较.结果 应用被动模式可测出大鼠的AERP.虽幼年鼠的潜伏期和幅值分别略长于和低于成年鼠,但在统计学上无显著性意义.大鼠AERP的波形与人基本上相似,但反应性和稳定性不如人类.结论 大鼠存在着与人类相似的AERP波形,并随年龄有一个发育、分化和成熟的过程,这一过程的完成可能较早.大鼠可作为研究AERP神经生理机制的实验动物.     

Test-retest consistency of speech-evoked auditory brainstem responses in typically-developing children

The click-evoked auditory brainstem response (ABR) is widely used in clinical settings, partly due to its predictability and high test-retest consistency. More recently, the speech-evoked ABR has been used to evaluate subcortical processing of complex signals, allowing for the objective assessment of biological processes underlying auditory function and auditory processing deficits not revealed by responses to clicks. Test-retest reliability of some components of speech-evoked ABRs has been shown for adults and children over the course of months. However, a systematic study of the consistency of the speech-evoked brainstem response in school-age children has not been conducted. In the present study, speech-evoked ABRs were collected from 26 typically-developing children (ages 8-13) at two time points separated by one year. ABRs were collected for /da/ presented in quiet and in a 6-talker babble background noise. Test-retest consistency of response timing, spectral encoding, and signal-to-noise ratio was assessed. Response timing and spectral encoding were highly replicable over the course of one year. The consistency of response timing and spectral encoding found for the speech-evoked ABRs of typically-developing children suggests that the speech-evoked ABR may be a unique tool for research and clinical assessment of auditory function, particularly with respect to auditory-based communication skills.     

Cortical, auditory, event-related potentials in response to periodic and aperiodic stimuli with the same spectral envelope

OBJECTIVE: 1) To determine whether the N1-P2 acoustic change complex is elicited by a change of periodicity in the middle of an ongoing stimulus, in the absence of changes of spectral envelope or rms intensity. 2) To compare the N1-P2 acoustic change complex with the mismatch negativity elicited by the same stimuli in terms of amplitude and signal to noise ratio. DESIGN: The signals used in this study were a tonal complex and a band of noise having the same spectral envelope and rms intensity. For elicitation of the acoustic change complex, the signals were concatenated to produce two stimuli that changed in the middle (noise-tone, tone-noise). Two control stimuli were created by concatenating two copies of the noise and two copies of the tone (noise-only, tone-only). The stimuli were presented using an onset-to-onset interstimulus interval of 3 sec. For elicitation of the mismatch negativity, the tonal complex and noise band stimuli were presented using an oddball paradigm (deviant probability = 0.14) with an onset-to-onset interstimulus interval of 600 msec. The stimuli were presented via headphones at 80 dB SPL to 10 adults with normal hearing. Subjects watched a silent video during testing. RESULTS: The responses to the noise-only and tone-only stimuli showed a clear N1-P2 complex to the onset of stimulation followed by a sustained potential that continued until the offset of stimulation. The noise-tone and tone-noise stimuli elicited an additional N1-P2 acoustic change complex in response to the change in periodicity occurring in the middle. The acoustic change complex was larger for the tone-noise stimulus than for the noise-tone stimulus. A clear mismatch negativity was elicited by both the noise band and tonal complex stimuli. In contrast to the acoustic change complex, there was no significant difference in amplitude across the two stimuli. The acoustic change complex was a more sensitive index of peripheral discrimination capacity than the mismatch negativity, primarily because its average amplitude was 2.5 times as large. CONCLUSIONS: These findings indicate that both the acoustic change complex and the mismatch negativity are sensitive indexes of the neural processing of changes in periodicity, though the acoustic change complex has an advantage in terms of amplitude. The results support the possible utility of the acoustic change complex as a clinical tool in the assessment of peripheral speech perception capacity.     

Test-retest reliability of auditory brainstem responses to chirp stimuli in newborns

Abstract

Objective: The purpose of this study was to examine the test-retest reliability of auditory brainstem responses (ABRs) to air- and bone-conducted chirp stimuli in newborns as a function of intensity. Design: A repeated measures quasi-experimental design was employed. Study sample: Thirty healthy newborns participated. ABRs were evoked using 60, 45, and 30 dB nHL air-conducted CE-Chirps and 45, 30, and 15 dB nHL bone-conducted CE-Chirps at a rate of 57.7/s. Measures were repeated by a second tester. Results: Statistically significant correlations (p <.0001) and predictive linear relations (p <.0001) were found between testers for wave V latencies and amplitudes to air- and bone-conducted CE-Chirps. There were also no statistically significant differences between testers with wave V latencies and amplitudes to air- and bone-conducted CE-Chirps (p >.05). As expected, significant differences in wave V latencies and amplitudes were seen as a function of stimulus intensity for air- and bone-conducted CE-Chirps (p <.0001). Conclusions: These results suggest that ABRs to air- and bone-conducted CE-Chirps can be reliably repeated in newborns with different testers. The CE-Chirp may be valuable for both screening and diagnostic audiologic assessments of newborns.