Developmental dyslexics show deficits in the processing of temporal auditory information in German vowel length discrimination

Abstract

The present study investigated auditory temporal processing in developmental dyslexia by using a vowel length discrimination task. Both temporal and phonological processing were studied in a single experiment. Seven German vowel pairs differing in vowel height were used. The vowels of each pair differed only with respect to vowel length (e.g., /a/ vs. /a:/). In German, vowel length is characterized by temporal and spectral information. Three types of differences between long versus short vowels were varied: In the phonological condition, pairs of natural vowels were used, differing in their temporal as well as in their spectral content. In two temporal conditions, in contrast, a natural vowel was always combined with a manipulated one to keep spectral content of long and short vowels identical. Thus, the only distinguishing feature between the two vowels was temporal in nature. Vowels were embedded into monosyllabic pseudo-words and presented successively in a speeded same-different task. Twenty dyslexics and twenty age-matched controls participated in the experiment. In both groups, discrimination accuracy decreased with increasing vowel height in the two temporal conditions. This result is consistent with former findings on the relevance of temporal information for vowel length identification in German and extends this topic to cover discrimination demands. In the phonological condition, groups did not differ in discrimination accuracy. In both temporal conditions, however, dyslexics performed worse than controls. These results suggest that developmental dyslexia is associated with impairments in processing basic acoustic parameters of the speech signal, in particular, with a deficit in temporal processing.

Enhancement of brain event-related potentials to speech sounds is associated with compensated reading skills in dyslexic children with familial risk for dyslexia

“…In dyslexics, poor speech perception manifests itself as difficulties to discriminate and categorize speech sound contrasts like syllables, consonants and vowels (e.g., . Nevertheless, there are studies that fail to find differences between dyslexics and controls for some speech contrasts (Blomert et al, 2004;Groth et al, 2011). For example, Groth et al (2011) found that dyslexics were poorer in discriminating longer vowels from shorter ones if they were made shorter by manipulation (only durational cues available), but they found no group effect for naturally shorter versus longer vowels (both spectral and durational cues available).…”

“…Nevertheless, there are studies that fail to find differences between dyslexics and controls for some speech contrasts (Blomert et al, 2004;Groth et al, 2011). For example, Groth et al (2011) found that dyslexics were poorer in discriminating longer vowels from shorter ones if they were made shorter by manipulation (only durational cues available), but they found no group effect for naturally shorter versus longer vowels (both spectral and durational cues available). Further, using functional magnetic resonance imaging (fMRI), Steinbrink et al (2012) observed decreased activation of left inferior frontal gyrus and insular cortices in dyslexics during processing of the same temporal stimuli, but only in the subgroup of low performing dyslexics (Steinbrink et al, 2012).…”

Relying on brain rhythms for improving the diagnosis of dyslexia

“…However, preliterate children at risk for dyslexia have been found to exhibit an atypical lateralization for this oscillatory frequency band (Vanvooren et al, 2014). Phoneme discrimination has proven to be a confident criterion for differentiating poor and normal reading abilities (Hämäläinen et al, 2009, Brunner, Bäumer, Rosenauer, Scheller, & Plinkert, 2010Groth, Lachmann, Riecker, Muthmann, & Steinbrink, 2011;Steinbrink, Klatter, & Lachmann, 2014), and in fact, this is an ability that emerges very early during language 14 acquisition (Kuhl, 1979;Shahidullah & Hepper, 1994;Cheour-Luhtanen et al, 1995).…”

Developing advanced mathematical models for detecting abnormalities in 2D/3D medical structures.

“…In addition, fMRI has been used extensively to analyze brain functionality in dyslexia during phonological processing [216][217][218][219][220][221][222]. For example, Shaywitz et al [216] analyzed fMRI activation patterns of 26 dyslexic subjects and 23 control subjects during a phonological analysis task.…”

“…The control subjects exhibited activation in the left middle temporal gyrus area, whereas this area showed disturbed activity in dyslexics. Groth et al [219] used fMRI to study the auditory temporal and phonological processing in dyslexic individuals using a German vowel length discrimination task. Dyslexic subjects performed worse than controls in response to temporal processing, whereas they did not differ in response to phonological processing.…”