Neurophysiological Indexes of Speech Processing Deficits in Children with Specific Language Impairment
Program in Hearing Sciences, City University of New York, New York, NY 10016, USA. Journal of Cognitive Neuroscience
(Impact Factor: 4.09).
08/2005; 17(7):1168-80. DOI: 10.1162/0898929054475217
We used neurophysiological and behavioral measures to examine whether children with specific language impairment (SLI) have deficits in automatic processing of brief, phonetically similar vowels, and whether attention plays a role in such deficits. The neurophysiological measure mismatch negativity (MMN) was used as an index of discrimination in two tasks; one in which children ignored the auditory stimuli and watched a silent video and a second in which they attended to the auditory modality. Children with SLI showed good behavioral discrimination, but significantly poorer behavioral identification of the brief vowels than the children with typical language development (TLD). For the TLD children, two neurophysiological measures (MMN and a later negativity, LN) indexed discrimination of the vowels in both tasks. In contrast, only the LN was elicited in either task for the SLI group. We did not see a direct correspondence between the absence of MMN and poor behavioral performance in the children with SLI. This pattern of findings indicates that children with SLI have speech perception deficiencies, although the underlying cause may vary.
Available from: Arild Hestvik
- "The largest factor observed in the data was related to the first spatial decomposition of the first temporal factor, TF1SF1. This factor matched the temporospatial location of the Late Discriminatory Negativity (Cheour et al., 1998; Datta, Shafer, Morr, Kurtzberg, & Schwartz, 2010; Korpilahti, Lang, & Aaltonen, 1995; Shafer, Morr, Datta, Kurtzberg, & Schwartz, 2005; Shestakova, Huotilainen, Ceponiene, & Cheour, 2003; C ˇ eponien, Cheour, & Näätänen, 1998), i.e., a late, slow, negativity with a broad anterior inferior distribution , peaking at FCz (EGI channel 6). The effect was driven by a large negativity when /d/ was the deviant, with no such effect for / t/. "
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ABSTRACT: In long-term memory, the phoneme units that make up words are coded for the distinctive features and feature values that are necessary to distinguish between words in the mental lexicon. Underspecification theory says that the phonemes that have unmarked feature values are even more abstract in that the feature is omitted from the representation altogether. This makes phoneme representations in words more sparse than the fully specified phonetic representations of the same words. Eulitz and Lahiri (2004) demonstrated that this theory predicts certain asymmetries in the Mismatch Negativity (MMN) response to phoneme contrasts. We expand on this research by demonstrating underspecification-driven asymmetry in the brain response to laryngeal feature contrasts in English (i.e. what makes /d/ and /t/ different). We add a new test by showing that the asymmetry disappears if the MMN paradigm is modified to encourage the formation of phonetic memory traces instead of phonemic memory traces. This result adds further neurobiological evidence that long-term phonological representations are more sparsely represented than phonetic representations.
Available from: Miwako Hisagi
- "One drawback of studies that examine speech processing in these classic, preattentive oddball paradigms is that isolated speech contrasts are repeated multiple times, and, thus, constitute an unnatural context. A different pattern might be found for more natural speech, although we have demonstrated that these vowel stimuli can be categorized by native listeners and are sensitive to language status (typical or impaired) in earlier studies (Datta et al., 2010; Shafer et al., 2005, 2007). The resynthesized nature of the vowel stimuli could also have led to listeners processing them as non-speech sounds. "
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ABSTRACT: This study examined behavioral and neurophysiological indices of discrimination of an English vowel contrast [ɪ–ɛ] by early and late bilingual Spanish–English speakers, compared to monolingual English speakers. Electrophysiological measures (Mismatched Negativity – MMN) and behavioral measures (AX discrimination and forced-choice identification) were employed to examine perception of a nine-step vowel continuum, re-synthesized from natural tokens. Results revealed that (i) both monolingual and early bilinguals showed similar behavioral perception while late bilinguals performed more poorly on all behavioral tasks; and (ii) monolinguals showed robust evidence of discrimination (MMN) at a pre-attentive level that was significantly larger than found for either early or late bilinguals. These findings suggested that early input of English vowels to bilinguals did not necessarily lead to robust, automatic processing, as measured at a more attention-independent neural level; but earlier experience with a second language allowed for native-like speech perception measured with behavioral tasks.
Available from: Elyse Sussman
- "Reduced amplitude MMN is generally thought to reflect poorer representations of the phonetic categories within the speaker's native language, which may be the result of poor auditory resolution or poor language-specific learning of relevant phonetic cues (e.g., Shafer et al. 2005; Datta et al. 2010). One study of 6-year-old children at risk for dyslexia, in addition to reduced MMN to phonemic contrasts (e.g., / ba/ vs. /da/) observed larger MMN to a within-category difference (allophonic variants of /ba/) in the at-risk children compared to the matched controls (Noordenbos et al. 2012). "
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ABSTRACT: Cognition is often affected in a variety of neuropsychiatric, neurological, and neurodevelopmental disorders. The neural discriminative response, reflected in mismatch negativity (MMN) and its magnetoencephalographic equivalent (MMNm), has been used as a tool to study a variety of disorders involving auditory cognition. MMN/MMNm is an involuntary brain response to auditory change or, more generally, to pattern regularity violation. For a number of disorders, MMN/MMNm amplitude to sound deviance has been shown to be attenuated or the peak-latency of the component prolonged compared to controls. This general finding suggests that while not serving as a specific marker to any particular disorder, MMN may be useful for understanding factors of cognition in various disorders, and has potential to serve as an indicator of risk. This review presents a brief history of the MMN, followed by a description of how MMN has been used to index auditory processing capability in a range of neuropsychiatric, neurological, and neurodevelopmental disorders. Finally, we suggest future directions for research to further enhance our understanding of the neural substrate of deviance detection that could lead to improvements in the use of MMN as a clinical tool.
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