Effects of Reading and Writing on Cerebral Laterality in Good Readers and Children with Dyslexia

Abstract

The present study evaluated the idea that the hemisphere-specific cognitive demands of reading and writing may induce task-specific maladaptive patterns of language lateralization in children with dyslexia. Situation-specific lateralization was examined in a repeated measures design under three dichotic listening conditions: baseline, concurrent reading, and concurrent writing. Twelve males with phonological dyslexia, 8 to 12 years old, were compared to 12 age-matched and 12 younger reading-matched good readers. Lateralization patterns were examined for condition-specific relationships to pseudoword decoding, word recognition, reading comprehension, spelling, and arithmetic. The results show that dyslexia is not related to incomplete lateralization or to a failure to inhibit verbal processing in the right hemisphere during reading and writing. Reading increased the lateralization of the children with dyslexia, which had a negative relation to arithmetic; writing caused a decrease in lateralization, which was linked specifically to deficits in phonological decoding and visual word recognition. The results suggest that children with dyslexia suffer from a selective linguistic vulnerability to left-hemisphere interference from the idiosyncratic attentional and processing demands of particular school tasks. Dyslexia is a much more dynamic and environmentally sensitive disorder than previously thought.

Ipsilateral printing in children's mirror-writing: A cause of specific learning disabilities?

“…Mather, 2001). For example in two dichotic listening studies that involved reporting different digits delivered simultaneously to each ear, children with dyslexia differed from controls in producing a decrease in LH lateralization for written but not oral reports (Kershner, Henninger, & Cooke, 1984; Kershner & Stringer, 1991). This decrease correlated with phonological decoding difficulties with real words and pronounceable nonwords.…”

Does Dyslexia Develop from Learning the Alphabet in the Wrong Hemisphere? A Cognitive Neuroscience Analysis

“…Along the same lines, dyslexics have been found to make more CV identification errors in written than in oral expression (Lieberman, Meskill, Chattillon, & Schupack, 1985) and in dichotic digit listening, children conforming to the WW subtype differ from controls and the LL subtype in switching from a right ear/LH advantage for oral responses to a left ear/RH advantage for written responses, due primarily to poorer right ear recall (Kershner, Henninger, & Cooke, 1984;Kershner & Stringer, 1991). Further, pseudoword writing slows the pen speed of WW dyslexics but speeds that of the LL subtype (Seymour, 1987)-the latter result consistent with the strong right ear advantage demonstrated by this subtype in dichotic CV listening (Cohen, Hynd, & Hugdahl, 1992)-and WW dyslexics are less dextral and LL dyslexics more dextral than controls on measures of hand preference and skill (Annett, Eglinton, & Smythe, 1996).…”

The Role of Dichotic Listening Performance and Tasks of Executive Functions in Reading Impairment: A Discriminant Function Analysis

“…Performance on directed attention dichotic tasks discriminates between groups of learning disabled children and both age and reading matched controls (Asbjørnsen & Bryden, 1998;Bakker & Kappers, 1988;Boliek, Obrzut, & Shaw, 1988;Helland & Asbjørnsen, 2000, 2001Hiscock & Kinsbourne, 1982;Hugdahl, Ellertsen, Waaler, & Kløve, 1989;Hynd, Obrzut, Weed, & Hynd, 1979;Kershner & Graham, 1995;Kershner & Micallef, 1991;Kershner & Micallef, 1992;Kershner & Morton, 1990;Obrzut, 1988;Obrzut, Boliek, & Bryden, 1997;Obrzut, Conrad, Bryden, & Boliek, 1988;Obrzut, Horgesheimer, & Boliek, 1999;Obrzut, Hynd, & Obrzut, 1983;Obrzut, Hynd, Obrzut, & Leitgeb, 1980). Few studies have addressed how DL performance could be related to the reading impairment per se and/or additional cognitive impairment (Bakker & Kappers, 1988;Kershner, Henninger, & Cooke, 1984;Kershner & Micallef, 1991;Kershner & Stringer, 1991), or whether DL performance could identify subgroups of learning disabled children (Obrzut, Hynd, & Obrzut, 1983). Obrzut, Hynd, and Obrzut (1983) found that the directed dichotic tasks contributed the most of a total of 13 cognitive neuropsychological tasks to the discrimination between learning disabled and normal reading children in a stepwise discriminant function analysis.…”