Search results for "Speech recognition"
showing 10 items of 357 documents
Sequential grouping modulates the effect of non-simultaneous masking on auditory intensity resolution.
2012
The presence of non-simultaneous maskers can result in strong impairment in auditory intensity resolution relative to a condition without maskers, and causes a complex pattern of effects that is difficult to explain on the basis of peripheral processing. We suggest that the failure of selective attention to the target tones is a useful framework for understanding these effects. Two experiments tested the hypothesis that the sequential grouping of the targets and the maskers into separate auditory objects facilitates selective attention and therefore reduces the masker-induced impairment in intensity resolution. In Experiment 1, a condition favoring the processing of the maskers and the targ…
The effect of MPEG audio compression on multidimensional set of voice parameters
2002
The MPEG-1 Layer 3 compression schema of audio signal, or commonly known as mp3, has caused a great impact in recent years as it has reached high compression rates while also conserving a high sound quality. Previous listening tests have shown that music and speech samples compressed at high bitrates are virtually indistinguishable from the original samples, but very little is known about how compression acoustically affects the voice signal. In Experiment 1 the spectral composition of original and compressed speech signals were analyzed by means of the Long-Term Average Spectrum using the Computerized Speech Laboratory (Kay Elemetrics Corp. (Pine Brook, NJ, USA)). In Experiment 2 a set of …
Two Distinct Auditory-Motor Circuits for Monitoring Speech Production as Revealed by Content-Specific Suppression of Auditory Cortex
2015
Speech production, both overt and covert, down-regulates the activation of auditory cortex. This is thought to be due to forward prediction of the sensory consequences of speech, contributing to a feedback control mechanism for speech production. Critically, however, these regulatory effects should be specific to speech content to enable accurate speech monitoring. To determine the extent to which such forward prediction is content-specific, we recorded the brain's neuromagnetic responses to heard multisyllabic pseudowords during covert rehearsal in working memory, contrasted with a control task. The cortical auditory processing of target syllables was significantly suppressed during rehear…
Proactive interference of a sequence of tones in a two-tone pitch comparison task
2000
Subjects compared pitches of a standard tone and a comparison tone separated by 1,300-3,000 msec and responded according to whether the comparison tone sounded higher or lower in pitch than the standard tone. Three interfering tones at 300-msec intervals were presented before each pair of tones. Their pitch range varied, being either below or above the pitch of the standard tone; in some of the trials, their pitches were identical to the pitch of the standard tone (no interference). The highest error rate in performance was found when the interfering tones and the comparison tone deviated in the same direction in pitch from the standard tone. In turn, their deviations in the opposite direct…
Macrostructural EEG characterization based on nonparametric change point segmentation: application to sleep analysis
2001
In the present investigation a new methodology for macrostructural EEG characterization based on automatic segmentation has been applied to sleep analysis. A nonparametric statistical approach for EEG segmentation was chosen, because it minimizes the need for a priori information about a signal. The method provides the detection of change-points i.e. boundaries between quasi-stationary EEG segments based on the EEG characteristics within four fundamental frequency bands (delta, theta, alpha and beta). Polysomnographic data of 18 healthy subjects were analyzed. Our findings show that nonparametric change-point segmentation in combination with cluster analysis enables us to obtain a clear pic…
Dimension reduction: additional benefit of an optimal filter for independent component analysis to extract event-related potentials.
2011
The present study addresses benefits of a linear optimal filter (OF) for independent component analysis (ICA) in extracting brain event-related potentials (ERPs). A filter such as the digital filter is usually considered as a denoising tool. Actually, in filtering ERP recordings by an OF, the ERP' topography should not be changed by the filter, and the output should also be able to be modeled by the linear transformation. Moreover, an OF designed for a specific ERP source or component may remove noise, as well as reduce the overlap of sources and even reject some non-targeted sources in the ERP recordings. The OF can thus accomplish both the denoising and dimension reduction (reducing the n…
Can letter position encoding be modified by visual perceptual elements?
2018
A plethora of studies has revealed that letter position coding is relatively flexible during word recognition (e.g., the transposed-letter [TL] pseudoword CHOLOCATE is frequently misread as CHOCOLATE). A plausible explanation of this phenomenon is that letter identity and location are not perfectly bound as a consequence of the limitations of the visual system. Thus, a complete characterization of letter position coding requires an examination of how letter position coding can be modulated by visual perceptual elements. Here we conducted three lexical decision experiments with TL and replacement-letter pseudowords that manipulated the visual characteristics of the stimuli. In Experiment 1,…
Visual tracking combined with hand-tracking improves time perception of moving stimuli
2014
A number of studies have shown that performing a secondary task while executing a time-judgment task impairs performance on the latter task. However, this turns out not to be the case for certain motor secondary tasks. We show that concomitant secondary motor tasks involving pointing, when performed during a time-judgment task, can actually improve our time-judgment abilities. We compared adult participants' performance in a time-of-movement paradigm with visual pursuit-only and with visual pursuit plus hand pursuit. Rather than interfering with their estimation of stimulus movement duration, the addition of hand pursuit significantly improved their judgment. In addition, we considered the …
Position but not color deviants result in visual mismatch negativity in an active oddball task.
2009
Changes in the visual environment might be detected automatically. This function is provided by the sensory systems and showed, for instance, by the pop-out phenomenon. Automatic change detection is also observable within visual oddball paradigms, where rare changes are introduced in an irrelevant stimulus feature; the detection of deviant stimuli is accompanied by a negative component (so-called visual mismatch negativity) in the human event-related brain potential. In this study, the deviating stimulus feature was embedded in a task-relevant object presented in the focus of attention. With this, visual mismatch negativity was observable only with position deviants presented in the upper v…
Vocal fold strain and vocal pitch in singing:Radiographic observations of singers and nonsingers
1998
Summary The relationship between vocal fold strain and vocal pitch in singersand nonsingers singing a rising pitch series has been indirectly investigated by means of lateral radiographs. Nonsingers tend to exhibit more strain than singers. To standardize the degree of strain, an index of strain per semitone is proposed. The semitone strain indicates the average amount of strain per 1 semitone of pitch increase or decrease. The index has been shown to be affected by several factors: gender, singing training, singing technique, voice class, age, and status of muscle function. Observations suggest that similar groups of individuals occupy different positions on the stress-strain curve, indica…