Comparison of auditory steady-state response and click-evoked auditory brain response in infants with different types and degrees of hearing loss

Abstract

Background: Auditory steady-state response (ASSR) and click-evoked auditory brain response (c-ABR) have been used for hearing assessment for decades years, the correlation of the two methods and the effects of type and degree of hearing loss (HL) to the correlation in infants younger than 6?months of age are unclear.

Objectives: To compare the correlation of ASSR and c-ABR and then to analyse the effects of type and degree of HL on the correlation in infants younger than 6?months of age.

Material and methods: Retrospective study comparing ASSR thresholds at various frequencies with c-ABR thresholds. 182 ears from 96 infants were assessed and classified according to types and degrees of HL.

Results: The correlation coefficients were: 0.823, 0.864, 0.891, 0.871, 0.908, 0.915 and 0.913 between ASSR thresholds at 0.5, 1, 2, 4, 2–4, 1–2–4, 0.5–1–2–4?kHz and c-ABR thresholds respectively. The correlation coefficients in the group of sensorineural HL (SHL) (r?=?0.763–0.900) were higher than conductive HL (r?=?0.309–0.619) across all frequencies. The coefficients of severe-profound SHL (r?=?0.595–0.790) were higher than mild-moderate SHL (r?=?0.434–0.687) across all frequencies.

Conclusions and significance: ASSR was one valuable cross-check measure by providing frequency specific information in auditory assessment.     

Sensorineural hearing loss (SNHL) as an adverse event following immunization (AEFI): Case definition & guidelines for data collection,analysis, and presentation of immunization safety data

This is a Brighton Collaboration case definition of the term “Sensorineural Hearing Loss” to be utilized in the evaluation of adverse events following immunization. The case definition was developed by a group of experts convened by the Coalition for Epidemic Preparedness Innovations (CEPI) in the context of active development of vaccines for Lassa Fever and other emerging pathogens. The case definition format of the Brighton Collaboration was followed to develop a consensus definition and define levels of diagnostic certainty, after an exhaustive review of the literature and expert consultation. The document underwent peer review by the Brighton Collaboration Network.     

Rapid Increase in Neural Conduction Time in the Adult Human Auditory Brainstem Following Sudden Unilateral Deafness

Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.     

Sensory evoked potentials in patients with Rett syndrome through the lens of animal studies: Systematic review

ObjectiveSystematically review the abnormalities in event related potential (ERP) recorded in Rett Syndrome (RTT) patients and animals in search of translational biomarkers of deficits related to the particular neurophysiological processes of known genetic origin (MECP2 mutations).MethodsPubmed, ISI Web of Knowledge and BIORXIV were searched for the relevant articles according to PRISMA standards.ResultsERP components are generally delayed across all sensory modalities both in RTT patients and its animal model, while findings on ERPs amplitude strongly depend on stimulus properties and presentation rate. Studies on RTT animal models uncovered the abnormalities in the excitatory and inhibitory transmission as critical mechanisms underlying the ERPs changes, but showed that even similar ERP alterations in auditory and visual domains have a diverse neural basis. A range of novel approaches has been developed in animal studies bringing along the meaningful neurophysiological interpretation of ERP measures in RTT patients.ConclusionsWhile there is a clear evidence for sensory ERPs abnormalities in RTT, to further advance the field there is a need in a large-scale ERP studies with the functionally-relevant experimental paradigms.SignificanceThe review provides insights into domain-specific neural basis of the ERP abnormalities and promotes clinical application of the ERP measures as the non-invasive functional biomarkers of RTT pathophysiology.     

自动听性脑干反应联合声导抗鼓室图在疑似听力障碍婴幼儿中的应用

目的 探讨自动听性脑干反应(AABR)联合声导抗鼓室图在听力筛查中的应用价值,以寻求更适合于基层单位推广的新生儿听力筛查方案。方法 2013年1月-2016年12月选取本院门诊疑似听力障碍婴幼儿558例,同时接受AABR和鼓室图的联合筛查,疑似感音神经性耳聋患者进行听力诊断。结果 1 116耳同时接受AABR与鼓室声导抗联合筛查,504耳为一次性通过两项联合筛查,79耳为一月后复查通过两项联合筛查,20耳为通过听力诊断判为正常。最终共诊断分泌性中耳炎11耳,咽鼓管功能障碍46耳,感音神经性耳聋456耳。结论 AABR联合声导抗鼓室图检测可以有效提高听力筛查的准确性,有利于听力障碍患儿的早发现早干预,建议基层单位进行推广。     

Quantitative evaluation of ventricular dilatation using computed tomography in infants with congenital cytomegalovirus infection

Background

Infants with congenital cytomegalovirus infection (CCMVI) may develop brain abnormalities such as ventricular dilatation, which may potentially associate with sensorineural hearing loss. There is currently no recognized method for quantitative evaluation of ventricle size in infants with CCMVI. Our objectives were to establish a method for quantitative evaluation of ventricle size using computed tomography (CT) in infants with CCMVI, and determine a cut-off value associated with abnormal auditory brainstem response (ABR) early in life.

Design/Subjects

This study enrolled 19 infants with CCMVI and 21 non-infected newborn infants as a control group. Infants with CCMVI were divided into two subgroups according to ABR at the time of initial examination: normal ABR (11 infants) or abnormal ABR (8 infants). Ventricle size was assessed by calculating Evans’ index (EI) and lateral ventricle width/hemispheric width (LVW/HW) ratio on brain CT images, and was compared among groups. A cut-off ventricle size associated with abnormal ABR was determined.

Results

EI and LVW/HW ratio were significantly higher in the CCMVI with abnormal ABR group than the control and CCMVI with normal ABR groups. Cut-off values of 0.26 for EI and 0.28 for LVW/HW ratio had a sensitivity of 100% and 100%, respectively, and a specificity of 73% and 91%, respectively, for association with abnormal ABR.

Conclusions

We established a method for quantitative evaluation of ventricle size using EI and LVW/HW ratio on brain CT images in infants with CCMVI. LVW/HW ratio had a more association with abnormal ABR in the early postnatal period than EI.     

Deficits in motor performance after pedunculopontine lesions in rats – impairment depends on demands of task

Anatomically and functionally located between basal ganglia and brainstem circuitry, the pedunculopontine tegmental nucleus (PPTg) is in a pivotal position to contribute to motor behavior. Studies in primates have reported akinesia and postural instability following destruction of the PPTg. In humans, the PPTg partially degenerates in Parkinson's disease and stimulation of this region is under investigation as a possible therapeutic. Studies in rats report no crude motor impairment following PPTg lesion, although a detailed assessment of the role of the PPTg in rat motor function has not been reported. Our studies applied motor tests generally used in rodent models of Parkinson's disease to rats bearing either excitotoxic damage to all neuronal populations within PPTg, or selective destruction of the cholinergic subpopulation created with the toxin Dtx‐UII. Neither lesion type altered baseline locomotion. On the rotarod, excitotoxic lesions produced a persistent impairment on the accelerating, but not fixed speed, conditions. In the vermicelli handling task (a quantitative measure of fine motor control and effective behavioral sequencing) excitotoxic lesions produced no single impairment, but globally increased the number of normal and abnormal behaviors. In contrast, depletion of cholinergic PPTg neurons produced impairment on the accelerating rotarod but no changes in vermicelli handling. Together, these results show that while PPTg lesions produce no impairment in the execution of individual motor actions, impairments emerge when the demands of the task increase. Results are discussed in terms of PPTg acting as part of a rapid action selection system, which integrates sensory information into motor output.