The effect of working memory training on auditory stream segregation in auditory processing disorders children

Objectives: This study investigated the efficacy of working memory training for improving working memory capacity and related auditory stream segregation in auditory processing disorders children. Methods: Fifteen subjects (9-11 years), clinically diagnosed with auditory processing disorder participated in this non-randomized case-controlled trial. Working memory abilities and auditory stream segregation were evaluated prior to beginning and six weeks after completing the training program. Ten control subjects, who did not participate in training program, underwent the same battery of tests at time intervals equivalent to the trained subjects. Differences between the two groups were measured using a repeated measures analysis of variance. Results: The results of this study indicated children who received auditory working memory training performed significantly better on working memory abilities and auditory stream segregation task than children do not received training program. Discussion: Results from this case-control study support the benefits of working memory training for children with auditory processing disorders and indicate that training of auditory working memory is especially important for this population

Effects of an auditory lateralization training in children suspected to central auditory processing disorder

Background and Objectives: Central auditory processing disorder (C)APD refers to a deficit in auditory stimuli processing in nervous system that is not due to higher-order language or cognitive factors. One of the problems in children with (C)APD is spatial difficulties which have been overlooked despite their significance. Localization is an auditory ability to detect sound sources in space and can help to differentiate between the desired speech from other simultaneous sound sources. Aim of this research was investigating effects of an auditory lateralization training on speech perception in presence of noise/competing signals in children suspected to (C)APD. Subjects and Methods: In this analytical interventional study, 60 children suspected to (C)APD were selected based on multiple auditory processing assessment subtests. They were randomly divided into two groups: control (mean age 9.07) and training groups (mean age 9.00). Training program consisted of detection and pointing to sound sources delivered with interaural time differences under headphones for 12 formal sessions (6 weeks). Spatial word recognition score (WRS) and monaural selective auditory attention test (mSAAT) were used to follow the auditory lateralization training effects. Results: This study showed that in the training group, mSAAT score and spatial WRS in noise (p value�0.001) improved significantly after the auditory lateralization training. Conclusions: We used auditory lateralization training for 6 weeks and showed that auditory lateralization can improve speech understanding in noise significantly. The generalization of this results needs further researches. © 2016 The Korean Audiological Society

Relation between working memory capacity and auditory stream segregation in children with auditory processing disorder

Background: This study assessed the relationship between working memory capacity and auditory stream segregation by using the concurrent minimum audible angle in children with a diagnosed auditory processing disorder (APD). Methods: The participants in this cross-sectional, comparative study were 20 typically developing children and 15 children with a diagnosed APD (age, 9-11years) according to the subtests of multiple-processing auditory assessment. Auditory stream segregation was investigated using the concurrent minimum audible angle. Working memory capacity was evaluated using the non-word repetition and forward and backward digit span tasks. Nonparametric statistics were utilized to compare the between- group differences. The Pearson correlation was employed to measure the degree of association between working memory capacity and the localization tests between the 2 groups. Results: The group with APD had significantly lower scores than did the typically developing subjects in auditory stream segregation and working memory capacity. There were significant negative correlations between working memory capacity and the concurrent minimum audible angle in the most frontal reference location (0° azimuth) and lower negative correlations in the most lateral reference location (60° azimuth) in the children with APD. Conclusion: The study revealed a relationship between working memory capacity and auditory stream segregation in children with APD. The research suggests that lower working memory capacity in children with APD may be the possible cause of the inability to segregate and group incoming information. © 2016, Shiraz University of Medical Sciences. All rights reserved

Wavelet Decomposition-Based Analysis of Mismatch Negativity Elicited by a Multi-Feature Paradigm

In this study, event-related potentials (ERPs) collected from normally hearing subjects and elicited by a multi-feature paradigm were investigated, and mismatch negativity (MMN) was detected. Standard stimuli and five types of deviant stimuli were presented in a specified sequence, while EEG data were recorded digitally at a 1024 sec–1 sampling rate. Two wavelet analyses were compared with a traditional difference-wave (DW) method. The Reverse biorthogonal wavelet with an order of 6.8 and the quadratic B-Spline wavelet were applied for seven-level decomposition. The sixth-level approximation coefficients were appropriate for extracting the MMN from the averaged trace. The results obtained showed that wavelet decomposition (WLD) methods extract MMN as well as a band-pass digital filter (DF). The differences of the MMN peak latency between deviant types elicited by B-Spline WLD were more significant than those extracted by the DW, DF, or Reverse biorthogonal WLD. Also, wavelet coefficients of the delta-theta range indicated good discrimination between some combinations of the deviant types.У суб’єктів із нормальним слухом реєстрували пов’язані з подією потенціали, викликані з використанням множинної парадигми. Стандартні слухові стимули та девіантні стимули п’яти типів пред’являли в специфічній послідовності; ЕЕГ-потенціали відводили з частотою дискретизації 1024 c–1. Результати двох видів вейвлет-аналізу порівнювали з даними, отриманими із застосуванням традиційного методу диференціації хвиль (DW). Зворотний біортогональний вейвлет порядку 6.8 і квадратичний B-сплайновий вейвлет використовували для декомпозиції сьомого порядку. Коефіцієнти наближення шостого порядку виявилися застосовними для виділення негативності розузгодження (MMN) із усереднених записів. Як показали результати, методи вейвлет-декомпозиції (WLD) дозволяють виділити негативність розузгодження так само успішно, як і цифрові фільтри. Відмінності латентних періодів піків негативності розузгодження для девіантних варіантів стимуляції, виявлені в разі застосування В-сплайнової WLD, були більш вірогідними, ніж аналогічні відмінності при використанні методу диференціації хвиль, цифрової фільтрації або зворотної біортогональної WLD. Вейвлет-коефіцієнти для дельта-тета-діапазону також дозволяли отримати найкращу дискримінацію деяких комбінацій девіантних типів

Spectro-temporal modulation detection and its relation to speech perception in children with auditory processing disorder

Objectives: Poor speech perception in noise is one of the most common complaints reported for children with auditory processing disorder (APD). APD is defined as a deficit in perceptual processing of acoustic information in the auditory system in which decreased spectro-temporal resolution may also contribute. Since the recognition of spoken message in the context of other sounds, is based on the processing of auditory spectro-temporal modulations, the assessment of spectro-temporal modulations sensitivity can evaluate the listener's ability to retrieve and integrate speech segments covered by noise. Therefore, the purpose of this study was to examine spectro-temporal modulation (STM) detection and its relation to speech perception in children with APD and to compare the results with aged-matched normally developed children. Methods: 35 children with APD and 32 normal hearing children (8�12 years old) were enrolled. In order to examine STM detection performance, six different STM stimulus conditions were employed using three different temporal modulation rates (4, 12 and 32 Hz) and two different spectral modulation densities (0.5 and 2.0 cycles/octave). Initially, the STM detection thresholds at these six STM stimulus conditions were measured in both groups and the results were compared. Thereafter, the relation between STM detection thresholds and speech perception tests, including consonant-vowel in noise and word in noise tests were assessed. Results: The STM sensitivity was poorer than normal for APD children at all STM stimulus conditions. Children with APD displayed significantly poorer STM detection thresholds than those of normally developed children (p < 0.05). Significant correlations were found between STM detection thresholds and speech perception in noise in both groups (p < 0.05). Conclusion: The results suggest that the altered encoding of spectro-temporal acoustic cues in the auditory nervous system may be one of the underlying factors of reduced STM detection performance in children with APD. The present study may suggest that poor ability to extract STM cues in children with APD, can be an underlying factor for their listening problems in noise and poor speech perception in challenging situations. © 2020 Elsevier B.V

Nonlinear feature extraction for objective classification of complex auditory brainstem responses to diotic perceptually critical consonant-vowel syllables

Objective: To examine if nonlinear feature extraction method yields appropriate results in complex brainstem response classification of three different consonant vowels diotically presented in normal Persian speaking adults. Methods: Speech-evoked auditory brainstem responses were obtained in 27 normal hearing young adults by using G.tec EEG recording system. 170 ms synthetic consonant-vowel stimuli /ba/, /da/, /ga/ were presented binaurally and the recurrence quantification analysis was performed on the responses. The recurrence time of second type was proposed as a suitable feature. ANOVA was also used for testing the significance of extracted feature. Post-comparison statistical method was used for showing which means are significantly different from each other. Results: Dimension embedding and state space reconstruction were helpful for visualizing nonlinearity in auditory system. The proposed feature was successful in the objective classification of responses in window time 20.1�35.3 ms, which belonged to formant transition period of stimuli. Also the p value behavior of recurrence time of second type feature as a discriminant feature was close to the nature of the response that includes transient and sustained parts. On the other hand, the /ba/ and /ga/ classification period was wider than the others. Conclusion: The extracted feature shown in this paper is helpful for the objective of distinguishing individuals with auditory processing disorders in the structurally similar voices. On the other hand, differing nonlinear feature is meaningful in a special region of response, equal to formant transition period, and this feature is related to the state space changes of brainstem response. It can be assumed that more information is within this region of signal and it is a sign of processing role of brainstem. The state changes of system are dependent on input stimuli, so the existence of top down feedback from cortex to brainstem forces the system to act differently. © 2015 Elsevier Ireland Lt

Central auditory processing during chronic tinnitus as indexed by topographical maps of the mismatch negativity obtained with the multi-feature paradigm

This study aimed to compare the neural correlates of acoustic stimulus representation in the auditory sensory memory on an automatic basis between tinnitus subjects and normal hearing (NH) controls, using topographical maps of the MMNs obtained with the multi-feature paradigm. A new and faster paradigm was adopted to look for differences between 2 groups of subjects. Twenty-eight subjects with chronic subjective idiopathic tinnitus and 33 matched healthy controls were included in the study. Brain electrical activity mapping of multi-feature MMN paradigm was recorded from 32 surface scalp electrodes. Three MMN parameters for five deviants consisting frequency, intensity, duration, location and silent gap were compared between the two groups. The MMN amplitude, latency and area under the curve over a region of interest comprising: F3, F4, Fz, FC3, FC4, FCz, and Cz were computed to provide better signal to noise ratio. These three measures could differentiate the cognitive processing disturbances in tinnitus sufferers. The MMN topographic maps revealed significant differences in amplitude and area under the curve for frequency, duration and silent gap deviants in tinnitus subjects compared to NH controls. The current study provides electrophysiological evidence supporting the theory that the pre-attentive and automatic central auditory processing is impaired in individuals with chronic tinnitus. Considering the advantages offered by the MMN paradigm used here, these data might be a useful reference point for the assessment of sensory memory in tinnitus patients and it can be applied with reliability and success in treatment monitoring. © 2013 Elsevier B.V. All rights reserved