Presence Of Babble Noise Research Articles

Multilevel Modeling of Gaze From Listeners With Hearing Loss Following a Realistic Conversation.

There is a need for tools to study real-world communication abilities in people with hearing loss. We outline a potential method for this that analyzes gaze and use it to answer the question of when and how much listeners with hearing loss look toward a new talker in a conversation. Twenty-two older adults with hearing loss followed a prerecorded two-person audiovisual conversation in the presence of babble noise. We compared their eye-gaze direction to the conversation in two multilevel logistic regression (MLR) analyses. First, we split the conversation into events classified by the number of active talkers within a turn or a transition, and we tested if these predicted the listener's gaze. Second, we mapped the odds that a listener gazed toward a new talker over time during a conversation transition. We found no evidence that our conversation events predicted changes in the listener's gaze, but the listener's gaze toward the new talker during a silence-transition was predicted by time: The odds of looking at the new talker increased in an s-shaped curve from at least 0.4 s before to 1 s after the onset of the new talker's speech. A comparison of models with different random effects indicated that more variance was explained by differences between individual conversation events than by differences between individual listeners. MLR modeling of eye-gaze during talker transitions is a promising approach to study a listener's perception of realistic conversation. Our experience provides insight to guide future research with this method.

Exploring the role of singing, semantics, and amusia screening in speech-in-noise perception in musicians and non-musicians

Sentence repetition has been the focus of extensive psycholinguistic research. The notion that music training can bolster speech perception in adverse auditory conditions has been met with mixed results. In this work, we sought to gauge the effect of babble noise on immediate repetition of spoken and sung phrases of varying semantic content (expository, narrative, and anomalous), initially in 100 English-speaking monolinguals with and without music training. The two cohorts also completed some non-musical cognitive tests and the Montreal Battery of Evaluation of Amusia (MBEA). When disregarding MBEA results, musicians were found to significantly outperform non-musicians in terms of overall repetition accuracy. Sung targets were recalled significantly better than spoken ones across groups in the presence of babble noise. Sung expository targets were recalled better than spoken expository ones, and semantically anomalous content was recalled more poorly in noise. Rerunning the analysis after eliminating thirteen participants who were diagnosed with amusia showed no significant group differences. This suggests that the notion of enhanced speech perception—in noise or otherwise—in musicians needs to be evaluated with caution. Musicianship aside, this study showed for the first time that sung targets presented in babble noise seem to be recalled better than spoken ones. We discuss the present design and the methodological approach of screening for amusia as factors which may partially account for some of the mixed results in the field.

Effects of urgent speech and congruent/incongruent text on speech intelligibility for older adults in the presence of noise and reverberation

Public address (PA) announcements are widely used, but noise and reverberation can render them unintelligible, and such an environment tends to degrade speech intelligibility more for older adults (OAs) than for younger adults (YAs). Furthermore, in an emergency, textual information available to the public may not coincide with PA announcements, and this mismatch may also contribute to degrading the intelligibility of the announcement. In this study, speech spoken in a normal or urgent style and preceded by congruent or incongruent text was presented to OA participants to investigate the effects of these parameters on word intelligibility in the presence of babble noise and reverberation. This study also investigated age-related differences between OAs and YAs using the same stimuli. The results showed that, while YAs performed better than OAs, the effect of urgent speech did not significantly differ with age. Urgent speech was more intelligible than normal speech, and the congruent text condition was more intelligible than the incongruent and no text conditions. An exploratory analysis showed that urgent speech improved speech intelligibility for OAs when congruent text was available, but not when absent or incongruent. Without congruent information, this listening test may have been too demanding for OAs, who could have had more difficulty processing the fixed timeline of the listening test, the faster urgent speech relative to normal speech, and informational masking because of the slowing of cognitive processing with age. A correlation was found between the average word correct rate for urgent speech and average audiometric thresholds; on the other hand, increased fundamental frequencies in urgent compared with normal speech was not the main predictor of the intelligibility of urgent speech among the OAs. The congruent text benefit in urgent speech was larger for OAs than for YAs in the previous study using the same stimuli. This demonstrates that compared with YAs, OAs may rely more on supportive prior knowledge or receive more benefit from the preceding text in challenging listening environments. These findings imply that age-related cognitive decline may explain the difficulties in speech perception in the presence of noise and reverberation among OAs; however, no definitive conclusions can be drawn. These results suggest that simple combinations of speaking style and textual information affect the intelligibility of emergency PA announcements among OAs, and thus, audiovisual congruence should be considered when announcements are made in public spaces.

Auditory attention detection: Application in neuro-steered hearing aids

State-of-the-art hearing prostheses are equipped with acoustic noise reduction algorithms to improve speech intelligibility. However, cocktail party scenarios with multiple speakers pose a major challenge since it is difficult for the algorithm to determine which speaker it should enhance. To address this problem, electroencephalography (EEG) signals can be used to perform auditory attention detection (AAD), i.e., to detect which speaker the listener is attending to. Taking a step further towards realization of a neuro-steered hearing prosthesis, we worked on AAD-assisted noise suppression in a competing-speakers scenario in the presence of babble noise. We use an EEG-informed AAD module in combination with a blind source separation algorithm to extract the per-speaker envelopes from the microphone recordings, as well as a multi-channel Wiener filter to extract the denoised speech signal(s). Using a new algorithm pipeline, we obtain better AAD accuracies, and a better robustness to variations in speaker positions and signal-to-noise ratios (SNR), compared to previously reported results. Furthermore, the algorithm allows to switch more swiftly to the other speaker’s stream when there is a switch in attention.

Speech accommodation to room acoustics: Reverberation time and clarity

Vocal effort is a physiological entity that accounts for changes in voice production as vocal loading increases, which can be quantified in terms of sound pressure level (SPL). This study investigates how vocal effort is affected by speaking style, room acoustics, and short-term vocal fatigue. Twenty subjects were recorded while reading a text at normal and loud volumes in anechoic, semi-reverberant, and reverberant rooms in the presence of babble noise. The acoustics in each environment were modified by increasing the strength of the early reflections in the talker position. The subjects answered questions addressing their perception of vocal effort, comfort, control, and the clarity of their own voice. SPL variation for each subject was measured per task. It was found that SPL and self-reported effort increased in the loud style and decreased when the reflective panels were present and when reverberation time increased. In contrast, self-reported comfort and control decreased in the loud style, while self-reported clarity increased when panels were present. SPL was higher for females than for males. The lowest magnitude of apparent short-term vocal fatigue was experienced by talkers in the semi-reverberant room. The results indicate that reflections may be used to reduce vocal effort without modifying reverberation time.

Effects of hearing loss on heart rate variability and skin conductance measured during sentence recognition in noise.

The purpose of the study was to determine the effects of hearing loss and noise on (1) two autonomic nervous system measures associated with stress (skin conductance and heart rate variability) and on (2) subjective ratings of workload/stress. The authors hypothesized that hearing loss would increase psychophysiological and subjective reactivity to noise during speech recognition tasks. Both psychophysiological and subjective indicators of workload/stress were expected to increase with a reduction in signal-to-noise ratio. Sentence recognition in the presence of babble noise was assessed in 15 adults with clinically normal hearing and 18 adults with sensorineural hearing loss. Mean sentence recognition was equalized for the two groups using an adaptive procedure to estimate 80% recognition of words in sentences. Sentences were then presented in quiet and at four fixed signal-to-noise ratios: -6, -3, 0, and +3 dB relative to the individually determined signal-to-noise thresholds. Electrocardiography and skin conductance recordings were obtained during each listening condition. The high-frequency spectral component of heart rate variability was extracted from the electrocardiographic recordings as a measure of parasympathetic nervous system activity. Subjective ratings of effort, mental demand, stress, and perceived performance were obtained after each listening condition using the National Aeronautics and Space Administration Task Load Index. Recognition scores referenced to the adaptive threshold were similar for the two groups. Participants with hearing loss showed a decrease in high-frequency heart rate variability at lower signal-to-noise ratios, whereas those with normal hearing did not. Skin conductance levels were not sensitive to changes in signal-to-noise ratio. However, overall skin conductance reactivity to noise (relative to quiet) was higher for those with hearing loss than for those with normal hearing. In contrast to the psychophysiological findings, there were no significant differences between subjective ratings for the two groups. Listeners with hearing loss show greater autonomic nervous system reactivity to babble noise during speech recognition than do listeners with normal hearing, when recognition performance is equal. The findings are consistent with the conclusion that listeners with hearing loss experience increased effort and/or stress during speech recognition in noise.

Quality of older voices processed by hearing aids: Acoustic factors explaining inter-talker differences

Hearing aid signal processing algorithms are often evaluated with professional recordings of voices. However, hearing aid users often listen to older talkers who may have poorer voices than younger talkers. The purpose of this study was to quantify the extent to which the acoustic and perceptual consequences of hearing aid digital signal processing algorithms differ for talkers that vary in their vocal characteristics. There were six older talkers (3 males and 3 females) selected from a larger database of 79 talkers; their voices had good, moderate, or poor quality based on perceptual data from younger and older listeners. The voices were presented in quiet and in the presence of babble noise (10 dB SNR). The voices were processed with varying amounts of frequency compression, wide dynamic range compression, and noise suppression (spectral subtraction). There were interactions between signal processing and voice characteristics as measured using the Hearing Aid Speech Quality Index (HASQI) and listener ra...

Quality of voices processed by hearing aids: Intra-talker differences

The effects of hearing aid signal processing depend on the voice characteristics of a talker. For example, we have found that the perceptual and acoustic consequences of hearing aid signal processing vary across talkers and that these effects can be explained, in part, by the acoustic differences between the different voices. However, we find that different utterances spoken by the same talker are also differentially affected by the hearing aid signal processing. In this study, we quantified the acoustic and perceptual consequences of hearing aid signal processing on several utterances spoken by the same talker. The voices were presented in quiet and in the presence of babble noise (10 dB SNR). The voices were processed with varying amounts of frequency compression, wide dynamic range compression and noise suppression (spectral subtraction). We considered intra-talker variability using an objective quality metric (Hearing Aid Sound Quality Index) and perceptual ratings of quality. We analyzed sentences from several different speech corpora, including the Hearing-in-Noise Test (HINT), IEEE, and TIMIT. The results showed interactions between the effects of signal processing and the acoustic characteristics of specific utterances spoken by an individual. [Work supported in part by GN ReSound and NSERC.]

Robust emotional speech classification in the presence of babble noise

Emotional speech recognition (ESR) is a new field of research in the realm of human-computer interactions. Most of the studies in this field are performed in clean environments. Nevertheless, in the real world conditions, there are different noise and disturbance parameters such as car noise, background music, buzz and etc., which can decrease the performance of such recognizing systems. One of the most common noises which can be heard in different places is the babble noise. Because of the similarity of this kind of noise to the desired speech sounds, babble or cross-talk, is highly challenging for different speech-related systems. In this paper, in order to find the most appropriate features for ESR in the presence of babble noise with different signal to noise ratios, 286 features are extracted from speech utterances of two emotional speech datasets in German and Persian. Then the best features are selected among them using different filter and wrapper methods. Finally, different classifiers like Bayes, KNN, GMM, ANN and SVM are used for the selected features in two ways, namely multi-class and binary classifications.

Intelligibility and listener preference of telephone speech in the presence of babble noise

Two procedures for improving the intelligibility of wideband telephone speech in the presence of competing babble noise are evaluated. One procedure is differentiation, the other consists of equalizing the speech spectrum by applying the inverse of the average spectrum of formant amplitudes for adult male speakers ("formant equalization"). Speech processed by these two methods was evaluated both for intelligibility and for listener preference. Both methods produced a clear increase in intelligibility compared to unprocessed wideband telephone speech. Formant equalization was found to be preferred over differentiation, more so at low signal-to-noise ratios than at high ones.

User Evaluation of a Communication System That Automatically Generates Captions to Improve Telephone Communication

This study examined the subjective benefit obtained from automatically generated captions during telephone-speech comprehension in the presence of babble noise. Short stories were presented by telephone either with or without captions that were generated offline by an automatic speech recognition (ASR) system. To simulate online ASR, the word accuracy (WA) level of the captions was 60% or 70% and the text was presented delayed to the speech. After each test, the hearing impaired participants (n = 20) completed the NASA-Task Load Index and several rating scales evaluating the support from the captions. Participants indicated that using the erroneous text in speech comprehension was difficult and the reported task load did not differ between the audio + text and audio-only conditions. In a follow-up experiment (n = 10), the perceived benefit of presenting captions increased with an increase of WA levels to 80% and 90%, and elimination of the text delay. However, in general, the task load did not decrease when captions were presented. These results suggest that the extra effort required to process the text could have been compensated for by less effort required to comprehend the speech. Future research should aim at reducing the complexity of the task to increase the willingness of hearing impaired persons to use an assistive communication system automatically providing captions. The current results underline the need for obtaining both objective and subjective measures of benefit when evaluating assistive communication systems.

Speech perception in noise by fluent, non-native listeners

This experiment measured the ability of fluent, non-native listeners to understand American English in the presence of babble noise. The Speech Perception in Noise (SPIN) test was administered at 75 dB SPL to 11 native and 14 non-native young, normal listeners. The non-native listeners were university students and teachers who had lived more than four years in the United States. Six noise levels were chosen in 2-dB steps to encompass the range from 20%–80% correct performance. At each noise level, 50 new sentences were presented and the percent correct for 25 low- and 25 high-predictability sentences was measured. After each sentence the listener wrote the last word in the sentence and repeated it to the experimenter, who also wrote it. Results show (1) the native listeners could obtain 50% correct performance at significantly higher noise levels (about 3 dB) than the non-native listeners, (2) both groups performed significantly better on the high-predictability sentences than on the low-predictability sentences, and (3) the difference in tolerable noise levels (levels yielding 50% correct) between the high- and low-predictability sentences was the same for the native and non-native groups. [Work supported by the Research and Scholarship Development Fund of Northeastern University.]