Subtypes of reading disability in a shallow orthography: a double dissociation between accuracy-disabled and rate-disabled readers of Hebrew

Abstract

Whereas most English language sub-typing schemes for dyslexia (e.g., Castles & Coltheart, 1993) have focused on reading accuracy for words varying in regularity, such an approach may have limited utility for reading disability sub-typing beyond English in which fluency rather than accuracy is the key discriminator of developmental and individual differences in reading ability. The present study investigated the viability of an accuracy/fluency-based typology in a regular orthography, pointed Hebrew. We sought evidence of true or "hard" accuracy/rate subtypes in the strict (double dissociation) sense of selective impairment on only one dimension in the presence of normal levels of performance on the other dimension. In a nationally representative sample of fourth graders, we were able to identify a specific accuracy-disabled sub-group as well as an equally specific rate-disabled subgroup. Validating this subdivision, we show that the nature of reading performance in these subgroups and their converging cognitive/linguistic profiles are unique and distinctive on variables other than the measures used to define them. While the rate-specific disability appeared to reflect a general deficit in speed of processing affecting reading rate, and rapid automatized naming of print-related material, the accuracy-only disability subgroup displayed selective deficits in phonological awareness and morphological knowledge. Biosocial, demographic, and instructional factors, furthermore, did not explain the sub-group differences. It appears that both these subtypes are equally prevalent each counting close to 10% of the population.

The effects of orthographic transparency and familiarity on reading Hebrew words in adults with and without dyslexia

“…Many dyslexic Hebrew readers, like dyslexics in other orthographies, show deficient phonological processing that is characterized by poor phoneme awareness and low decoding skills as compared to typical readers (Friedmann & Castles, 2013;Miller-Shaul, 2005;Shany & Share, 2010;Shany & Ben-Dror, 2011;Shany & Breznitz, 2011). These differences increase during development, while differences in orthographic processing decrease, suggesting that dyslexic readers develop a compensatory orthographic strategy over the years (Miller-Shaul, 2005).…”

“…Dyslexic participants had a score of at least one standard deviation below the average of the local norms in at least one of the two phonological tests: decoding and awareness. One standard deviation was chosen following a standard practice in the Hebrew literature (Breznitz, 2003;Cohen-Mimran, 2006;Shany & Share, 2010;. Typical readers were recruited from spouses and friends of the dyslexic participants, who were never diagnosed with reading impairments.…”

Different speed of processing levels in childhood and their contribution to early literacy and reading abilities

“…We used the low 25th percentile criterion for the slow group (Siegel, 1999;Shany & Share, 2011), the 75th percentile and above for the fast group, and between the 25th and 75th percentile for the average SOP group. Crosstabs analysis showed a significant connection between the divisions into three groups in kindergarten and first grade, 2 = 38.28, p < .001.…”

Exploring the Phenotype of Phonological Reading Disability as a Function of the Phonological Deficit Severity: Evidence from the Error Analysis Paradigm in Arabic

“…According to different researchers, this disability is attributable to phonological processing deficits (Caravolas, Kessler, Hulme & Snowling, 2005;Elbro & Pallesen, 2002). Many scholars tend to think that such disability is characterized by a heterogeneity that implies the existence of several subtypes (e.g., Shany & Share, 2011). The source of this heterogeneity has been an issue of debate among several researchers.…”

“…Hence, Snowling (2001) suggested that the variation seen in reading processes can be accounted for by differences in the severity of individual children's phonological deficits, which are modulated by compensatory factors including visual memory, perceptual speed, and exposure to print. The role of phonological processing in reading acquisition is emphasized during the first steps of learning to read in alphabetic orthographies (Defior, Martos, & Cary, 2002;Mannai & Everatt, 2005;Shany & Share, 2011;Ventura, Morais, Pattamadilok, & Kolinsky, 2004;Ziegler & Goswami, 2005;Ziegler, Jacobs, & Stone, 1996). In this regard, the first step is thought to rely on the understanding of the relationship between the speech sounds and their written representations (Adams, 1990;Ehri & Snowling, 2005;Frith, 1985;Ziegler & Goswami, 2005).…”