Spectral ripple discrimination in children with auditory processing disorder

Abstract

Objective: The purpose of this study was to examine developmental trends in spectral ripple discrimination (SRD) and to compare the performance of typically developing children to children with auditory processing disorder (APD).

Study design: Cross-sectional study.

Study sample: Fifteen children with APD, as well as 17 typically developing children and 14 adults reporting no listening or academic difficulties participated.

Results: Typically developing children showed poor SRD thresholds compared to adults, indicating prolonged maturation of spectral shape recognition. Both typically developing children and APD children showed a maturational trend in SRD, but a General Linear Model fit to their thresholds showed that children with APD displayed SRD thresholds that were significantly poorer than those of typically developing children when controlling for age. This suggests that in APD children, SRD maturation lags behind typically developing children.

Conclusion: Poor spectral ripple discrimination may explain some of the listening difficulties experienced by children with APD.     

Electrical stimulation of the auditory nerve: effects of pulse width on frequency discrimination.

Effects of pulse width on discrimination of simultaneous changes in frequency and level of electrical pulse trains were studied in a monkey subject with a cochlear implant. At test-stimulus levels where performance was minimum, frequency difference limens were larger for longer-duration pulses than that for shorter-duration pulses. Several factors may have contributed to these differences.     

Central auditory processing and word discrimination in patients with multiple sclerosis

Many multiple sclerosis (MS) patients with normal pure tone threshold suffer from difficulties in their hearing especially speech perception in background noise, which is possibly because of incompetence of central auditory processing in this group. Three audiologic tests including gap in noise test (GIN), duration pattern sequence test (DPST) and word discrimination score (WDS) were used for comparing a number of aspects of central auditory processing between patients with MS and normal subjects. Approximate threshold and percent of correct answers in GIN test, percent of correct answers in DPST test and monosyllabic discrimination in WDS test were obtained through cross-sectional non-invasive study conducted on 26 subjects with relapsing-remitting multiple sclerosis who had mean age of 28.9 (SD 4.1) years, and 26 18–40-year-old ones with normal hearing and mean age of 27.7 (SD 5.2). Results of this study demonstrate increased approximate threshold and reduction of percent of correct answers obtained from GIN test in patients with multiple sclerosis (Pv = 0.0001). Furthermore in patients with MS, the average of correct answers in DPST was lower than normal subjects and finally performance of MS subjects in WDS test in quiet environment was correlated with GIN threshold (r = ?/624, Pr = /003). Results of the present study showed that patients with MS had defect in aspects of central auditory processing consisting of temporal resolution, auditory pattern and the memory for auditory task and difficulty in discrimination of speech in noisy environment that are related to the involvement of central nervous system.     

Evaluation of auditory processing and phonemic discrimination in children with normal and disordered phonological development

Auditory processing and phonemic discrimination are essential for communication. Type of study: Retrospective.AimTo evaluate auditory processing and phonemic discrimination in children with normal and disordered phonological development.Material and MethodsAn evaluation of 46 children was carried out: 22 had phonological disorders and 24 had normally developing speech. Diotic, monotic and dichotic tests were applied to assess auditory processing and a test to evaluate phonemic discrimination abilities.DesignCross-sectional, contemporary.ResultsThe values of normally-developing children were within the normal range in all auditory processing tests; these children attained maximum phonemic discrimination test scores. Children with phonological disorders performed worse in the latter, and presented disordered auditory processing.ConclusionAuditory processing and phonemic discrimination in children with phonological disorders are altered.     

Deficits in auditory frequency discrimination and speech recognition in cochlear implant users

Abstract

Objectives

Speech recognition varies considerably following cochlear implantation for reasons that are still poorly understood. Considering the role of frequency discrimination in normal speech recognition, the aim of this study was to investigate the association between deficits in auditory frequency discrimination and speech recognition in cochlear implant users.

Methods

Frequency discrimination thresholds and speech recognition were assessed in a group of 20 cochlear implant users and 16 normally hearing controls.

Results

Based on their results on the speech recognition task, the cochlear implant users were categorized either as proficient (n = 10) or non-proficient users (n = 10). The non-proficient cochlear implant users had poorer auditory frequency discrimination compared to the normal hearing participants and proficient cochlear implant users (both P < 0.05). No significant difference was found between the proficient cochlear implant users and the normally hearing group (P > 0.05). Furthermore, a bivariate correlation analysis revealed a relationship between speech recognition and frequency discrimination.

Conclusions

The present findings suggest an association between auditory frequency discrimination and speech recognition proficiency in cochlear implant users. Although no causal link can be drawn from these data, possible reasons for this association are discussed.     

Induced suppression in spike responses to tone-on-noise stimuli in the auditory nerve of the pigeon

Spike potentials were recorded from single, afferent fibres in the pigeon auditory nerve. Pure-tone stimuli were presented in quiet and in combination with wide band noise. Presented alone, tones produced tuned response areas; noise generally drove spike rate to well above the spontaneous rate measured in quiet. When presented in combination with noise, tones up to 75 dB SPL at frequencies far from the fibre's response area had no effect on the noise-driven spike rate. As the tone frequency was shifted towards the response area, from above or below CF, suppression of the noise-driven spike rate became stronger until the tone reached the edge of the response area. Suppression of the noise-driven rate was directly proportional to the level of the tone. Within the area of response to the tone, tone-driven spike rates generally were unchanged or variably decreased (occasionally slightly increased) by tone-on-noise stimulation, depending on the relation of the tone frequency to CF and the level of the tone relative to that of the noise. Tuning properties were unaffected. It is suggested that in the pigeon, the suppression of driven spike rate during presentation of combination stimuli, which is common to all fibres, depends on the same mechanism as the suppression of spontaneous firing by tones that is observed in a proportion of fibres (Temchin, A.N. (1988), J. Comp. Physiol. A 163, 99-115; Hill et al., (1989) Hear. Res. 39, 37-48).     

Rapid adaptation depends on the characteristic frequency of auditory nerve fibers

When a tone burst is presented to the ear, the firing rate of single auditory nerve fibers is initially high, then rapidly declines toward a smaller value. The rate of this decline in gerbil is a complex function of stimulus frequency and intensity, and fiber characteristic frequency.     

Diversity of characteristic frequency rate-intensity functions in guinea pig auditory nerve fibres

Rate-intensity functions at characteristic frequency (CF) were recorded from single fibres in the auditory nerve of anaesthetised guinea pigs. Within the same animal, CF rate-intensity functions, although probably forming a continuum, could be conveniently divided into three groups; (1) Saturating; reach maximum discharge rate within 30 dB of threshold, (2) Sloping-saturation; initially rapid growth in discharge rate leading to a slower growth in discharge rate but not saturating and (3) Straight; approximately constant increase in firing rate per decibel increase in sound pressure up to the maximum sound pressures used. Thresholds for individual fibres were plotted relative to compound action potential thresholds at the appropriate frequency. Fibres with straight CF rate-intensity functions had the highest thresholds. Fibres of the saturating CF sloping-saturation CF rate-intensity type had thresholds intermediate between saturating and straight. There was a close relationship between the type of CF rate-intensity function exhibited by a fibre and its spontaneous discharge rate. Fibres with saturating CF rate-intensity functions generally had high spontaneous discharge rates (greater than 18/s), whereas those with straight CF rate-intensity functions generally had low spontaneous discharge rates (less than 0.5/s). The majority of fibres with sloping-saturation CF rate-intensity functions had spontaneous rates between 0.5/s and 18/s. There was a negative correlation (r = -0.59) between the logarithm of the spontaneous discharge rate and relative threshold at CF with the lowest spontaneous rate fibres having the highest thresholds and vice-versa. This diversity of CF rate-intensity functions has functional implications for both frequency and intensity coding at high sound pressures in the mammalian auditory system.     

Applicability of the P300 frequency pattern test to assess auditory processing

Temporal ordering and auditory attention are important skills in information processing, being evaluated by a behavioral test, as the frequency pattern test (FPT) in temporal ordering (TO) and electrophysiological testing, as the P300 in auditory attention.ObjectiveTo analyze the applicability of FPT and P300 as testing for auditory processing.MethodWe performed an integrative literature review, with papers that met the inclusion criteria, using the MedLine, LILACS and SciELO databases, with the keywords: hearing attention, P300 evoked potential, P300 and electrophysiology, temporal ordering, processing and FPT. We found 13 papers concerning the use of the TPF and 16 regarding the use of P300.ResultsThe TPF was the most used test in the evaluation of TO, presented in a diotic way in individuals with language disorders, musicians, blind people, rural workers and different age groups. The P300 is used in the frequency of 1000 Hz in the frequent stimulus and 2000 Hz for the rare stimulus, applicable in individuals of both genders, different age groups, and in patients with Down syndrome, liver cirrhosis, AIDS and Sleep Apnea Syndrome.ConclusionThe FPT and P300 are efficient instruments used to assess the intended skills.     

免疫性脑脊髓膜炎模型中听神经脱髓鞘病变与听觉诱发电位的变化

目的探索实验性免疫性脑脊髓膜炎模型中听神经脱髓鞘病变和ABR随时间的变化,以及这两种变化之间的关系。方法选取Wistar大鼠60只,随机分为实验组、对照组和正常组,分别皮下注射牛坐骨神经髓鞘碱蛋白和完全弗氏佐剂、完全弗氏佐剂、生理盐水。对所有实验动物在免疫前、免疫结束后1、2、3、4、5、6周进行ABR检查。每周随机抽取各组2只动物,2.5%戊二醛活体灌注后处死,电镜下观察听神经的变化。结果实验组动物听神经在给药后1周均出现脱髓鞘病变,给药后第3周达到高峰,随后自行缓解,在第6周基本恢复;ABR的阈值各组间无明显差异,实验组Ⅲ波潜伏期延长。结论免疫性脑脊髓膜炎模型中听神经的脱髓鞘病变发病后随时间自行缓解,与ABR的变化并不同步。     

A systematic review of electrophysiological outcomes following auditory training in school-age children with auditory processing deficits

Abstract

Objective: To systematically review the peer-reviewed literature on electrophysiological outcomes following auditory training (AT) in school-age children with (central) auditory processing disorder ([C]APD). Design: A systematic review. Study sample: Searches of 16 electronic databases yielded four studies involving school-aged children whose auditory processing deficits had been confirmed in a manner consistent with and and compared to a treated and/or an untreated control group before and after AT. A further three studies were identified with one lacking a control group and two measuring auditory processing in a manner not consistent with and . Results: There is limited evidence that AT leads to measurable electrophysiological changes in children with auditory processing deficits. Conclusion: The evidence base is too small and weak to provide clear guidance on the use of electrophysiological outcomes as a measure of AT outcomes in children with auditory processing problems. The currently limited data can only be used to suggest that click-evoked AMLR and tone-burst evoked auditory P300 might be more likely to detect such outcomes in children diagnosed with (C)APD, and that speech-evoked ALLR might be more likely to detect phonological processing changes in children without a specific diagnosis of (C)APD.     

周围神经脱髓鞘豚鼠模型听神经病变及听功能研究

目的:通过建立实验性变态反应性神经炎这一周围神经脱髓鞘动物模型,观察其听神经病变,初步探讨其听性脑干反应(ABR)和听神经复合动作电位(CAP)的改变。方法:以粗提的牛外周神经髓鞘碱性蛋白(MBP)作为抗原,免疫实验组豚鼠;对照组以生理盐水代替MBP。检测动物血清抗MBPIgG水平、坐骨神经传导速度,观察坐骨神经、听神经病理改变;检测ABR、CAP阈值及潜伏期;观察内耳病理损伤。结果:实验组血清抗MBPIgG水平升高,与对照组相比P<0.01;实验组坐骨神经传导速度减慢,与对照组相比P<0.05;透射电镜发现坐骨神经、听神经脱髓鞘改变;免疫前后实验组14只(26耳)出现ABR反应阈升高,伴Ⅰ、Ⅲ、Ⅴ波潜伏期明显延长,与对照组比较P<0.01,而Ⅰ～Ⅲ、Ⅲ～Ⅴ波间期与对照组比较P>0.05;CAPN1、N1波潜伏期延长,与对照组比较P<0.01;另有4只(8耳)仅出现潜伏期延长而无阈值升高;免疫组织化学显示内耳免疫损伤部位主要在蜗神经、内耳神经纤维、螺旋神经节;扫描电镜显示内毛细胞纤毛紊乱、胞质溢出。结论:实验性变态反应性神经炎动物模型作为一种可靠的周围神经脱髓鞘动物模型,其病变可累及听神经出现听神经脱髓鞘改变,ABR和CAP阈值升高、潜伏期明显延长,该模型可望成为探讨听神经脱髓鞘的听力学表现的一种有用的动物模型。     

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.