Relations between measures of speech-in-noise performance and measures of efferent activity

Individual differences in auditory perceptual abilities in noise are well documented, but the factors causing such variability are unclear. The purpose of this study was to determine if individual differences in responses measured from the auditory efferent system were correlated with individual variations in speech-in-noise performance. The relation between behavioral performance on three speech-in-noise tasks and two objective measures of the efferent auditory system were examined in thirty normal-hearing, young adults. Two of the speech-in-noise tasks measured an acceptable noise level (ANL), the maximum level of speech babble noise that a subject is willing to accept while listening to a story. ANL was determined for both monotic (story and noise in the same ear) and a dichotic condition (story and noise in opposite ears). The third speech-in-noise task evaluated speech recognition using monosyllabic words presented in competing speech babble. Auditory efferent activity was assessed by examining the resulting suppression of click-evoked otoacoustic emissions (CEOAEs) following the introduction of contralateral, broadband noise (BBN). The activity levels of the ipsilateral and contralateral acoustic reflex (AR) arcs were evaluated using pure-tones and BBN. Results showed significant correlations (p \u3c 0.01) between: (1) the contralateral AR Ts to BBN and contralateral suppression of CEOAEs, and (2) the monotic ANL (ANLm) and dichotic ANL (ANLd). Significant correlations (p \u3c 0.05) were also found between: (1) the monotic (right ear) speech recognition-in-babble task and the right, ipsilateral acoustic reflex threshold (ART), and (2) the dichotic ANL (ANLd) and the phoneme recognition-in-noise (PRnx)

THE EFFECT OF CONTRALATERAL PURE TONES ON THE COMPOUND ACTION POTENTIAL IN HUMANS

The compound action potential (CAP) has been suggested in the literature as an alternative to otoacoustic emissions (OAE) for evaluating the efferent auditory system, and is thought to overcome some of the drawbacks associated with OAE. However, very few studies have examined efferent influence on auditory nerve potentials in humans. To help address this need, the present study examines the effects of contralateral pure tones on the CAP onset and offset amplitudes. The general goal of this research is to assess the value of using the CAP as a potential clinical tool for the assessment of efferent auditory function. The CAP was recorded from the tympanic membranes (TM) of 18 normally-hearing young adults (10 males and 8 females) using three different stimuli: broadband clicks, 1 kHz, and 4 kHz tone pips. The signal level was either midway between CAP threshold and saturation, or at the minimum signal level that revealed a reliable CAP. Contralateral tones were presented at levels ranging from 20 to 70 dB HL in 10 dB steps. The frequencies of the contralateral tones were .5, 1, 2, 4, 8 kHz for the click CAP; .5, 1, 2 kHz for the 1 kHz CAP; and 2, 4, 8 kHz for the 4 kHz CAP. Results showed that maximum suppression of 1 kHz CAP onset amplitude was obtained in 7 out of 9 participants by the 1 kHz contralateral pure tone at 40 dB HL (.07 ìV ± .02). The 4 kHz CAP onset amplitude was maximally suppressed in 8 out of 9 participants by the 8 kHz contralateral pure tone at 30 dB HL (.07ìV ± .02). The click CAP offset amplitude was maximally suppressed in 4 out of 8 participants by the 8 kHz contralateral tone presented at 40 dB HL (.17 ìV ± .05). These results along with previous studies suggest that the efferent system is maximally stimulated by moderate signal level tones (i.e. 30 - 40 dB HL), and that the efferent activity is dependent on frequency cues of both the stimulus and suppressor tones. Other factors that might be affecting the efferent influence on CAP such as sound duration, phase, bandwidth, and periodicity need to be further investigated in humans using noninvasive techniques. The long term goal of this research is to lead to the development of more effective clinical tools for investigating the efferent auditory system

Electrophysiologic assessment of (central) auditory processing disorder in children with non-syndromic cleft lip and/or palate

Session 5aPP - Psychological and Physiological Acoustics: Auditory Function, Mechanisms, and Models (Poster Session)Cleft of the lip and/or palate is a common congenital craniofacial malformation worldwide, particularly non-syndromic cleft lip and/or palate (NSCL/P). Though middle ear deficits in this population have been universally noted in numerous studies, other auditory problems including inner ear deficits or cortical dysfunction are rarely reported. A higher prevalence of educational problems has been noted in children with NSCL/P compared to craniofacially normal children. These high level cognitive difficulties cannot be entirely attributed to peripheral hearing loss. Recently it has been suggested that children with NSCLP may be more prone to abnormalities in the auditory cortex. The aim of the present study was to investigate whether school age children with (NSCL/P) have a higher prevalence of indications of (central) auditory processing disorder [(C)APD] compared to normal age matched controls when assessed using auditory event-related potential (ERP) techniques. School children (6 to 15 years) with NSCL/P and normal controls with matched age and gender were recruited. Auditory ERP recordings included auditory brainstem response and late event-related potentials, including the P1-N1-P2 complex and P300 waveforms. Initial findings from the present study are presented and their implications for further research in this area —and clinical intervention—are outlined. © 2012 Acoustical Society of Americapublished_or_final_versio

Assessing brain activity related to speech production and perception using tonal stimuli

Speech processing was studied by looking at brain processes underlying speech perception and production. Existing models of speech and empirical data propose that producing speech decreases neural activity relative to perceiving speech (termed Speech-Induced Suppression - SIS). SIS is associated with monitoring the intended auditory targets against perceived speech output. SIS has been frequently reported at cortical levels but not at subcortical levels. If SIS occurs at subcortical levels, then speech processing models would be expanded to incorporate these in the internal sensory prediction (i.e. the intended auditory targets). Auditory tonal stimuli were used in this thesis. Such stimuli are commonly used in research on subcortical activity during speech perception. Knowing what the benchmark response (i.e. subcortical activity to tones in speech perception) looks like, allows us to compare our findings made during speech production to speech perception research. The first four studies recorded cortical activity using EEG, a common method in studying SIS. The same experimental conditions were used across the studies to facilitate comparison. The results showed a large variation in the magnitude and direction of the SIS effect across conditions and experiments. Even though mean amplitudes appeared to indicate than the cortical activity was indeed suppressed in some cases, when the random effects were controlled for using linear mixed models, the suppression was not significant. A potential explanation of this result might be that the alien voice auditory stimuli played during the experimental tasks were not recognised as one’s own. This mismatch would preclude occurrence of SIS. SIS was tested for the first time using functional near-infrared spectroscopy (fNIRS) using the same experimental conditions that were used in the EEG studies. The suppression of the fNIRS signal (HbO peaks) was not significant. However, the haemoglobin concentration plots suggested that the responses to conditions that involved vocalisation differed from those that did not. This thesis also describes attempts at recording subcortical responses (FFR) during speech production. SIS has been reported at the brainstem level in the past (Papanicolaou, Raz, Loring, & Eisenberg, 1986) but this required further exploration because of procedural issues in the study. Recording FFRs during vocalisation was attempted here to test whether subcortical activity is suppressed. This required the development of a processing pipeline to extract clean signals (FFR) from brainstem recordings during speech production. Recording FFRs during speech production turned out to be very challenging. Methodological improvements introduced in the later experiments improved signal quality but it was far from the standard achieved during speech perception. Combining these two strands of research, i.e. SIS on cortical and subcortical level, led to methodological improvements. The main theoretical contribution of the thesis is the finding that SIS cannot be consistently observed when an external audio stimulus is presented whilst speech production occurs concurrently. This result agrees with a previous finding which described that less prototypical speech sounds are less suppressed (Niziolek, Nagarajan, & Houde, 2013). These results support speech models which postulate that suppression is due to matching predicted and perceived feedback

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 128, May 1974

This special bibliography lists 282 reports, articles, and other documents introduced into the NASA scientific and technical information system in April 1974

Engineering data compendium. Human perception and performance. User's guide

The concept underlying the Engineering Data Compendium was the product of a research and development program (Integrated Perceptual Information for Designers project) aimed at facilitating the application of basic research findings in human performance to the design and military crew systems. The principal objective was to develop a workable strategy for: (1) identifying and distilling information of potential value to system design from the existing research literature, and (2) presenting this technical information in a way that would aid its accessibility, interpretability, and applicability by systems designers. The present four volumes of the Engineering Data Compendium represent the first implementation of this strategy. This is the first volume, the User's Guide, containing a description of the program and instructions for its use

Brain Tumour Classification Using Deep Features from Structural MRI

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