A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
The neurophysiological basis of the integration of written and heard syllables in dyslexic adults.
Tekijät: Mittag M., Thesleff P., Laasonen M., Kujala T.
Julkaisuvuosi: 2013
Lehti: Clinical Neurophysiology
Tietokannassa oleva lehden nimi: Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology
Lehden akronyymi: Clin Neurophysiol
Vuosikerta: 124
Numero: 2
Aloitussivu: 315
Lopetussivu: 26
Sivujen määrä: 12
ISSN: 1872-8952
DOI: https://doi.org/10.1016/j.clinph.2012.08.003
Tiivistelmä
Letter-speech sound integration in fluent readers takes place automatically and is dependent on temporal synchrony between letters and sounds. In developmental dyslexia, however, letter-speech sound associations are hard to learn, compromising accurate and fluent reading. We studied the effect of printed text on processing speech sounds in dyslexic and fluent adult readers.\nVisual stimuli were presented with sequences of spoken syllables including vowel or consonant changes, or changes in syllable intensity, frequency, or vowel duration. As visual material, written syllables or their scrambled images were used. The auditory stimuli were presented either synchronously with the visual stimuli or time delayed. The mismatch negativity (MMN), an index of automatic neural change detection, was recorded.\nMMN amplitudes were larger to syllable changes in combination with written syllables than with scrambled images in fluent readers. However, dyslexic readers showed no difference between syllables vs. scrambled image condition. Furthermore, MMNs to consonant and frequency changes peaked later in dyslexic than fluent readers.\nOur results suggest deficient and sluggish audiovisual integration in dyslexic individuals, which is not dependent on the phonological relevance of the deviant type.\nUnlike previous studies, our study included several different types of syllable changes presented with concurrent print, enabling us to determine in more detail the nature of the audiovisual deficit in dyslexia.\nOBJECTIVE\nMETHODS\nRESULTS\nCONCLUSIONS\nSIGNIFICANCE
Letter-speech sound integration in fluent readers takes place automatically and is dependent on temporal synchrony between letters and sounds. In developmental dyslexia, however, letter-speech sound associations are hard to learn, compromising accurate and fluent reading. We studied the effect of printed text on processing speech sounds in dyslexic and fluent adult readers.\nVisual stimuli were presented with sequences of spoken syllables including vowel or consonant changes, or changes in syllable intensity, frequency, or vowel duration. As visual material, written syllables or their scrambled images were used. The auditory stimuli were presented either synchronously with the visual stimuli or time delayed. The mismatch negativity (MMN), an index of automatic neural change detection, was recorded.\nMMN amplitudes were larger to syllable changes in combination with written syllables than with scrambled images in fluent readers. However, dyslexic readers showed no difference between syllables vs. scrambled image condition. Furthermore, MMNs to consonant and frequency changes peaked later in dyslexic than fluent readers.\nOur results suggest deficient and sluggish audiovisual integration in dyslexic individuals, which is not dependent on the phonological relevance of the deviant type.\nUnlike previous studies, our study included several different types of syllable changes presented with concurrent print, enabling us to determine in more detail the nature of the audiovisual deficit in dyslexia.\nOBJECTIVE\nMETHODS\nRESULTS\nCONCLUSIONS\nSIGNIFICANCE
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