An AER study of stop-consonant discrimination

Abstract

The purpose of this study was to explore hemispheric involvement in stop-consonant discrimination. Two experimental designs were used. In the first design, averaged evoked responses (AERs) to stop-consonant-vowel (CV) syllables were combined with AERs to nonspeech stimuli, in a paradigm similar to earlier studies, and were submitted to a principal components analysis and analyses of variance. In the second design, only the CV-syllable AERs were analyzed, in the same manner. When the responses to both CV and nonspeech stimuli were included in the analysis, the results were in agreement with those of earlier studies. However, when the nonspeech-stimuli AERs were removed from the analysis, the unilateral effects observed in prior studies were not replicated. The results of this research indicate the importance of considering experimental design and task variables before generalizing AER results to speech perception.It has been assumed since the late 1800s that the left hemisphere of the brain is somehow specialized for language. Indeed, the pervasiveness of various types of aphasia following injury to or disease of the left hemisphere in right-handed individuals gives credence to this view. But what exactly is the left hemisphere's role in speech perception? This question has not been an easy one to investigate. "Speech" is composed of many acoustically diverse elements, and hemispheric involvement in processing these elements has been difficult to determine.Results of dichotic listening studies have revealed a right-ear advantage (REA)-corresponding to a presumed left-hemisphere superiority-for certain types of phonetic stimuli (Kimura, 1961). Shankweiler and Studdert-Kennedy (1967) and Cutting (1974) found that an REA existed for stop-eonsonant-vowel (CV) stimuli. Stop consonants elicited the most marked REA, whereas the liquids Irl and III elicited a smaller REA (Cutting, 1974). Steady-state vowels did not appear to elicit a significant REA in either study. Molfese (1978) attempted to replicate some of Cutting's results but employed averaged evoked responses (AERs) rather than dichotic listening to demonstrate the differential hemispheric responses. Neuroelectrlc activity was measured by electrodes at T3 and T4 of the 10-20 electrode system (Jasper, 1958), referenced to linked earlobes. In a paradigm similar to Cutting's (1974) investigation, Molfese used CV syllables with normal (phonetic) transitions, CV syllables with inverted (nonphonetic) transitions, and a bandwidth variable-sine-wave-formant CV analogs-which had both phonetic and nonphonetic transitions. It should be noted that these stimuli, particularly those with sine-wave formants, are not readily compreThis research was based on the author's dissertation under the direction of Harry Hollien at the University of Florida. The author gratefully acknowledges his support of this project. The author's address is Department of Speech and Hearing Sciences, Indiana University, Bloomington, IN 47405. hended as spoken syllables, although with training they c...

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“…For example, Molfese, in a series of articles investigating speech perception cues such as voice onset time and place of articulation, noted consistent systematic effects across studies for each cue (Molfese, 1978; Molfese, 1980; Molfese & Schmidt, 1983). Moreover these effects were independently replicated using comparable analysis procedures (Gelfer, 1987; Segalowitz & Cohen, 1989). The rationale for the use of the PCA procedure is that it has proven successful in identifying temporal intervals of the ERPs where most of the variability occurred across subjects and ERPs.…”

Short‐ and long‐term auditory recognition memory in 14‐month‐old human infants: Electrophysiological correlates

“…For example, Molfese, in a series of papers investigating speech perception cues such as voice onset time and place of articulation, noted consistent systematic effects across studies for each speech cue (Molfese, 1978a(Molfese, , 1978b(Molfese, , 1980(Molfese, , 1984Molfese & Schmidt, 1983). Moreover, these effects have also been independently replicated using comparable analysis procedures (Geifer, 1987;Segalowitz & Cohen, 1989). The rationale for the use of this procedure is that it has proven successful both in identifying ERP regions where most of the variability occurred across ERPs and subjects, and subsequently in determining if the variability characterized by the different PCA extracted factors was because of systematic changes in the independent variables under investigation.…”

“…This analysis sequence followed the procedures used by Molfese (1989) in the earlier version of this familiar-novel discrimination paradigm. This analysis procedure has also been used extensively as well as successfully in programmatic research across a number of laboratories (Brown, Marsh, & Smith, 1979;Chapman, McCrary, Bragdon, & Chapman, 1979;Donchin, Tueting, Ritter, Kutas, & Heffley, 1975;Geifer, 1987;Molfese, 1978aMolfese, , 1978bMolfese & Molfese, 1979, 1980, 1985Ruchkin, Sutton, Munson, Silver, & Macar, 1981;Segalowitz & Cohen, 1989). For example, Molfese, in a series of papers investigating speech perception cues such as voice onset time and place of articulation, noted consistent systematic effects across studies for each speech cue (Molfese, 1978a(Molfese, , 1978b(Molfese, , 1980(Molfese, , 1984Molfese & Schmidt, 1983).…”

Discrimination of language skills at five years of age using event‐related potentials recorded at birth

“…This procedure has also been used successfully in previous studies. Although there are a variety of different analysis procedures which could be used to analyze the ERP data, this multivariate approach has produced consistent results in programmatic research across a number of laboratories (Brown et al, 1979;Chapman et al, 1979;Donchin, Teuting, Ritter, Kutas, & Heffley, 1975;Gelfer, 1987; D. L. Molfese, 1978aMolfese, , 1978b; D. L. Molfese & V. J. Molfese, 1979Molfese, , 1980Molfese, , 1985Ruchkin et al, 1981;Segajowitz & Cohen, 1989).…”

“…L. Molfese & Schmidt, 1983). Moreover, these effects have also been independently replicated using comparable analysis procedures (Gelfer, 1987;Segalowitz & Cohen, 1989). The rationale for the use of this procedure is that it has proven successful both in identifying regions of the ERP where most of the variability occurred across ERPs and subjects, and subsequently in determining if the variability characterized by the different factors was due to systematic changes in the independent variables under investigation.…”