Neuroelectrical correlates of categorical speech perception in adults

Southern Illinois University USA
Brain and Language (Impact Factor: 3.22). 02/1978; 5(1):25-35. DOI: 10.1016/0093-934X(78)90004-4


Auditory evoked potentials were recorded from the left and right hemispheres of 16 adults during a phoneme identification task. The use of multivariate statistics enabled researchers to identify a number of cortical processes related to categorical speech perception which were common to both hemispheres, as well as several which disinguished between the two hemispheres.

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    • "Speech sounds, for example, that are dominated by high frequency energy tend to elicit smaller amplitude N1 and P2 components than those elicited by speech sounds with spectral emphasis in the lower frequencies (Agung et al, 2006). The response amplitude, latency, and wave morphology will also vary substantially between and within subjects, with (1) varying levels of alertness (Hyde, 1997; Wunderlich & Cone-Wesson, 2006), (2) an inadequate signal to noise ratio (SNR) arising from an inadequate numbers of epochs within the averaged response (Molfese, 1978), or (3) heightened levels of background noise from a participant's restless state (Hyde, 1994). These scenarios lead to uncertainty in visual response detection methods. "
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    ABSTRACT: The detection of adult cortical auditory evoked potentials (CAEPs) can be challenging when the stimulus is just audible. The effectiveness of a statistic compared with expert examiners in (1) detecting the presence of CAEPs when stimuli were present, and (2) reporting the absence of CAEPs when no stimuli were present, was investigated. CAEPs recorded from ten adults, using two speech-based stimuli, five stimulus presentation levels, and non-stimulus conditions, were given to four experienced examiners who were asked to determine if responses to auditory stimulation could be observed, and their degree of certainty in making their decision. These recordings were also converted to multiple dependent variables and Hotelling's T2 was applied to calculate the probability that the mean value of any linear combination of these variables was significantly different from zero. Results showed that Hotelling's T2 was equally sensitive to the best of individual experienced examiners in differentiating a CAEP from random noise. It is reasonable to assume that the difference in response detection for a novice examiner and Hotelling's T2 would be even greater.
    International journal of audiology 12/2009; 48(12):833-42. DOI:10.3109/14992020903140928 · 1.84 Impact Factor
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    • "Thus, both standard as well as multivariate analyses of AERs across laboratories note right hemisphere discrimination of voicing contrasts. Similar effects have been found with 4-year-old children in a study that used CV tokens from a velar voicing continuum (Molfese & Hess, 1978). "
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    ABSTRACT: Voicing is an important phonetic dimension that distinguishes voiced (i.e., /b/) from voiceless-aspirated stop consonants (i.e.,/ph/) in English. Perception of discrete voicing categories is affected by a number of acoustic cues. The present paper reviews evidence from brain-damaged populations indicating that the perception of certain voicing cues is less dependent upon left hemisphere mechanisms than the ability to perceive place of articulation contrasts (e.g., /b/ vs./d/). In addition, electrophysiological and dichotic listening studies with neurologically normal individuals support the view that the right hemisphere may play a special role in the categorical processing of voicing. These findings are discussed in relation to current models of hemispheric specialization and laterality for language.
    Brain and Language 04/1997; 57(1):122-50. DOI:10.1006/brln.1997.1836 · 3.22 Impact Factor
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    ABSTRACT: Auditory evoked potentials (AEPs) were recorded from the left and right hemispheres of 10 adults who were listening to a series of auditory stimuli which varied along linguistic and acoustic dimensions. Discrete components of the brain’s electrical response to these different stimuli were isolated and identified. Phonetic distinctions based on transitional elements occurred only in the left hemisphere. Other cortical components were identified which were sensitive to hemisphere differences, place of articulation cues, and formant bandwidth. One component of the brain’s activity reflected hand preferences independently of hemispheric differences.
    Attention Perception & Psychophysics 05/1978; 23(3):237-243. DOI:10.3758/BF03204132 · 2.17 Impact Factor
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