Differential Effects Of Noise Research Articles

The impact of combined degradations: Intelligibility of disordered speech in noise

In the current study, the intelligibility of dysarthric speech in background noise was determined. Speech-shaped noise was mixed with neurologically healthy (control) and disordered (dysarthric) speech at a series of signal-to-noise ratios. In addition, bandpass filtered control and dysarthric speech conditions were assessed to determine the effect of noise on both naturally and artificially degraded speech. Both the amount of noise and type of speech significantly impacted intelligibility, but there was no interaction between the two factors. Thus, it appears that there is no differential effect of noise on dysarthric speech relative to control speech. Despite this lack of interaction, it is important to note that the intelligibility of dysarthric speech was substantially lower than the intelligibility of control speech at each of the signal-to-noise ratios. This supports the idea that patients with dysarthria and their communication partners should be advised to select a favorable listening environment for communication. Lastly, large-scale online crowdsourcing via Amazon Mechanical Turk was utilized to collect data for the current study. Findings and implications for this data collection approach will be discussed.

Neural indices of phonemic discrimination and sentence-level speech intelligibility in quiet and noise: A P3 study

This study examined how speech babble noise differentially affected the auditory P3 responses and the associated neural oscillatory activities for consonant and vowel discrimination in relation to segmental- and sentence-level speech perception in noise. The data were collected from 16 normal-hearing participants in a double-oddball paradigm that contained a consonant (/ba/ to /da/) and vowel (/ba/ to /bu/) change in quiet and noise (speech-babble background at a −3 dB signal-to-noise ratio) conditions. Time-frequency analysis was applied to obtain inter-trial phase coherence (ITPC) and event-related spectral perturbation (ERSP) measures in delta, theta, and alpha frequency bands for the P3 response. Behavioral measures included percent correct phoneme detection and reaction time as well as percent correct IEEE sentence recognition in quiet and in noise. Linear mixed-effects models were applied to determine possible brain-behavior correlates. A significant noise-induced reduction in P3 amplitude was found, accompanied by significantly longer P3 latency and decreases in ITPC across all frequency bands of interest. There was a differential effect of noise on consonant discrimination and vowel discrimination in both ERP and behavioral measures, such that noise impacted the detection of the consonant change more than the vowel change. The P3 amplitude and some of the ITPC and ERSP measures were significant predictors of speech perception at segmental- and sentence-levels across listening conditions and stimuli. These data demonstrate that the P3 response with its associated cortical oscillations represents a potential neurophysiological marker for speech perception in noise.

Effects of broadband noise on cortical evoked auditory responses at different loudness levels in young adults

Young adults with no history of hearing concerns were tested to investigate their /da/-evoked cortical auditory evoked potentials (P1-N1-P2) recorded from 32 scalp electrodes in the presence and absence of noise at three different loudness levels (soft, comfortable, and loud), at a fixed signal-to-noise ratio (+3 dB). P1 peak latency significantly increased at soft and loud levels, and N1 and P2 latencies increased at all three levels in the presence of noise, compared with the quiet condition. P1 amplitude was significantly larger in quiet than in noise conditions at the loudest level. N1 amplitude was larger in quiet than in noise for the soft level only. P2 amplitude was reduced in the presence of noise to a similar degree at all loudness levels. The differential effects of noise on P1, N1, and P2 suggest differences in auditory processes underlying these peaks. The combination of level and signal-to-noise ratio should be considered when using cortical auditory evoked potentials as an electrophysiological indicator of degraded speech processing.

Parallels between behavioral and neurochemical variability in the rat vacuous chewing movement model of tardive dyskinesia

The widely accepted rat vacuous chewing movement model for tardive dyskinesia could be more fully mined through greater focus on individual variability in vulnerability to this neuroleptic-induced behavior. We have examined parallels between behavioral and neurobiological variability within a cohort in order to evaluate the role that neurobiological factors might play in determining susceptibility to tardive dyskinesia. Inter-observer reliability and individual consistency across time, in both spontaneous and neuroleptic-induced vacuous chewing movements, were empirically demonstrated. While this behavior increased across 8 months of observation in both vehicle controls and haloperidol-treated rats, pre-treatment baselines were predictive of final levels across individuals only in the vehicle control group, not the haloperidol-treated group. Haloperidol-induced elevations in neostriatal D2 and GAD67 mRNA were not correlated with individual variability in haloperidol-induced vacuous chewing movements. Ambient noise during the observations was found to exacerbate chronic haloperidol-induced, but not spontaneous vacuous chewing movements. Significant correlations were found among the haloperidol-treated rats between nigral and tegmental GAD67 and tegmental α7 mRNA levels, measured by in situ hybridization histochemistry, and vacuous chewing movements, specifically in the noisy conditions. Variability in these secondary responses to primary striatal dopamine and GABA perturbations may play a role in determining vulnerability to vacuous chewing movements, and by analogy, tardive dyskinesia. Both the differential predictive value of baseline vacuous chewing movements and the differential effect of noise, between controls and haloperidol-treated rats, add to evidence that haloperidol-induced vacuous chewing movements are regulated, in part, by different mechanisms than those mediating spontaneous vacuous chewing movements.

The differential effect of noise on creative task performance

Abstract: The effect of an arousal manipulation on creativity task performance was investigated. Sixty, 80, and 100dB of noise were used to raise arousal levels in 72 undergraduates while they were individually assessed on creativity tasks. Two hypotheses were tested: The first was that noise would interfere with performance on creativity tasks, and the second was that high scorers would be resistant to this effect. Results supported the latter hypothesis. The noise‐induction appeared to have a differential effect. For highly original subjects, there was a curvilinear relationship between the noise and performance; this relationship was not reflected in the performance of subjects who scored low in originality. The major finding of this study was that research on the relationship between creativity and arousal may be difficult and misleading if the mediating role of individual differences in creativity are not considered.

Differential effect of noise on tasks of varying complexity.

Differential effect of noise on tasks of varying complexity.

Prediction of visual tracking proficiency on an A-scope presentation from the measured effects of noise and time.

Visual noise and temporal requirements of a compensatory tracking task were varied in order to determine time-on-target proficiency. Nine Ss were each given 32 trials in counterbalanced order, with problems varying as to visual noise and target acceleration. The display consisted of an A-scope with Ss task being to maintain a triangular pulse in the center of a stationary notch by manipulating a velocity controlled handwheel. The results were plotted as a family of curves describing probable success as a function of visual noise and task time allowed. Probability of success became greater as the time requirements became less severe, and when time requirements became more severe, not only did probability of success diminish, but the differential effects of noise became more pronounced. The authors suggested this approach as a method of predicting subsequent tracking behavior.