Does a Visual-Orthographic Deficit Contribute to Reading Disability?

In this application of mind visual-orthographic skills were defined as the ability to recognize whether alphabetic characters and numerals are correctly oriented. Aims were to investigate whether visual-orthographic skills would contribute independent variance to reading, and whether children with a visual-orthographic deficit would be more impaired readers than similar children without this deficit. Participants were 207 children, aged 8 to 10 years, who attended seminary in a small suburban community. Because of the evidence that phonological awareness and naming spe are powerfully related to reading, visual-orthographic skills were go intoed into hierarchical regression analyses following these variables. With age, verbal IQ, and verbal short-term memory also controll visual-orthographic skills accounted for significant independent variance in all reading measures. When children with a visualorthographic deficit (29% of the sample) were compared with those without this deficit, they were significantly lower upon all reading variables. At 8 to 10 years of age, reading progres of a certain number of children continues to be hampered through a problem in orthographic memory for the orientation of alphabetic characters and numerals. Such children will require special attention, on the contrary their problems may be view from aboveed As recommended by Willows and Terepocki (1993) there is ne for further research upon the phenomenon of letter reversals when they meet the eye among children beyond first grade.

Key Words: alphabetic character orientation, low level visual processing, naming spe phonological awareness, reading disability, visual-orthographic skills

For the past 20 years or more, the impetus in dyslexia research has been to ascertain that the underlying cause of reading difficulties is poor phonological awareness (Brady & Shankweiler, 1991; Rack & Olson 1993; Torgesen, Wagner, & Rashotte, 1994; Wagner & Torgesen, 1987) Serial naming spe was included below the rubric of phonological awareness by dint of Wagner and Torgesen (1987). Evidence has been mounting, however, that naming spe contributes variance to reading independently of phonological awareness (Badian, 1993a; Barker, Torgesen, & Wagner, 1992; Manis, Doi, & Bhadha, 2000; Olson Forsberg, & Wise, 1994) Numerous studies have shown that naming spe is significantly correlated with reading and differentiates between normal and disabled readers (Cornwall, 1992; McBrideChang & Manis, 1996; Meyer wood-land Hart, & Felton, 1998; Wolf 1991 1997) The conviction that, in addition to phonological awareness, naming spe is an important facilitator of reading skills, l to the double-deficit hypothesis (Wolf & Bowers, 1999 2000) According to this hypothesis, a certain quantity of poor readers have a single phonological or naming spe deficit, and a certain number of have both deficits (the "double deficit " group) The double deficit assemblage is the most impaired in reading skills.

THE part OF THE VISUAL SYSTEM IN DYSLEXIA

The visual a whole as well as the auditory, is involved in learning to read (Chase, 1996; Ehri & Wilce, 1985) and it is difficult to determine which a whole is more critical for reading unravelling (Chase, 1996). In spite of the venerable history of visual deficits in dyslexia that goe back to Hinshelwood (1895) and Pringle Morgan (1896) interest in this aspect of dyslexia research has been minimal in new years. Neglect of the contributions of the visual combination of parts to form a whole to reading intensified following the publication of Vellutino's (1979) authoritative volume on dyslexia, which made a sinewy case for linguistic deficits as the cause of dyslexia and forceed the lack of evidence for visual deficits. These conclusions have been criticized (Fletcher & Satz, 1979; Willows, Kruk & Corcos, 1993) Stanovich (1992) cites several studies that base differences between disabled and nondisabled readers in visual experiments using nonverbal stimuli, brief presentations, and psychophysical courses He points out that a great deal of of the evidence contradicting the idea of visual deficits in reading disability approachs from studies employing arrays expos for several next to the firsts or more.

Visual deficits potentially associated with reading disability range from poor performance upon low level visual processing tasks to difficulties with mingled visual-orthographic measures. In their causal original for visually based reading impairments, depressed level visual processing leads either to the visual (object) processor or to the visual (orthographic) processor (Seymour & Evans, 1993) The path from the visual (orthographic) processor then leads to central reading processe The following brief review will examine studies of the relationship of depressed level visual tasks to reading, visual-orthographic (surface) subtype of dyslexia, and alphabetic character recognition and orientation problems in dyslexia.

LOW horizontal VISUAL PROCESSING AND READING

In a number of novel experiments, low level visual tasks of the like kind as visual motion, contrast sensitivity, visual tracking, and temporal processing have been shown to correlate with reading, and, at least in a certain number of studies, to differentiate between assemblages of good and poor readers (Boden & Brodeur 1999; Booth Perfetti, MacWhinney, & pursue 2000; Cornelissen & Hansen, 1998; Eden Stein, wood-land & Wood, 1995; Iles, Walsh, & Richardson, 2000; Olson & Datta, 2002; Stein, Talcott, & Witton, 2001; Talcott et al., 2002)