Short summary of article: Students with significant reading difficulties can be sub grouped into 3 groups: (1) phonological awareness deficits only, (2) visual naming-speed deficits only, and (3) both deficits or "double-deficit". The double-deficit group was most impaired and the visual naming-speed group was least impaired. However, all groups made significant gains in reading after receiving focused and well-designed reading instruction. The double-deficit group had more difficulties in written expression than the other groups. Both phonological awareness and visual naming-speed difficulties persist into adulthood- even with individuals who become functionally literate. Phonological awareness skills are clearly amenable to treatment. It is still unknown whether visual naming-speed skills are amenable to treatment.

"The double-deficit hypothesis proposes that developmental reading disability can be characterized with respect to two highly specific deficits in separate aspects of speech, language, and visible language development. The first deficit, widely acknowledged to affect a majority of children with severe reading disabilities, is one of deficient phonological awareness. The second deficit, about which there is more controversy, concerns deficiencies in visual naming speed-specifically, significant impairments in rapidly accessing and retrieving names for visual symbols (Bowers, Steffy, & Swanson, 1986; Bowers & Swanson, 1991; Wolf, 1982; Wolf, Bally, & Morris, 1986; Wolf & Obergón, 1992)." p. 334

The authors addressed two specific questions:

1. Can a sample of children with severe reading disabilities be sub grouped on these two dimensions (phonological awareness and visual-naming speed)?

2. Would the two groups respond differently to reading interventions?

The answer to #1 was YES and the answer to #2 was NO. All three groups of students made significant gains from treatment interventions. The authors argue that all students should benefit because they had some shared deficiencies in word reading skills. However, authors did find differences between the groups. The double-deficit group was more impaired- especially in written language skills. The visual-naming speed only group was the least impaired.

"The present article includes a post hoc analysis of diagnostic and treatment outcome data collected on a referred and independently ascertained sample of 166 children with severe reading disabilities between the ages of 7 and 13." p. 336

Participants were assigned to 1 of 2 active treatment programs or to a control group: (1) word identification strategy training (WIST) &endash; a metacognitive phonics program; (2) phonological analysis and blending/direct instruction (PHAB/DI) program- used parts of DI program; and (3) academic survival skills and self-help strategies with no reading-related instruction (control group).

Children with reading disabilities were considered to have phonological deficits only, visual naming-speed deficits only, or both-a double-deficit. The majority of students had a double-deficit (54%). Twenty-two percent had phonological deficits and twenty-four percent had visual naming-speed deficits.

All subgroups were significantly impaired in all aspects of reading, spelling, and comprehension skill and in the development of letter-sound knowledge. However, children with a double deficit consistently demonstrated the lowest level of performance on any measure of reading development.

The most striking finding was that students with double-deficit (difficulties with both phonological awareness and visual naming-speed) had more difficulties with written expression in addition to their significant difficulties with reading. In contrast, students with only visual naming-speed difficulties were more selectively impaired; that is, they had difficulties with reading but they had less difficulty with written expression than students with a double-deficit.

Phonological processing deficits persist into adulthood- even when adults with childhood dyslexia were demonstrated to have achieved reasonable standards of literacy (Bruck, 1992; Pennington, Van Orden, Smith. Green, & Haith, 1990)." p. 335

Similar to the phonological core deficit, the visual naming-speed deficit appears to persist over time, characterizing individuals with RD from kindergarten (Wolf et al., 1986) through adulthood (Felton & Brown, 1990; Wolff, Michel, Ovrut, 1990; Wolff, Michel, Ovrut, & Drake, 1990)." p. 335

"These data indicate clearly that the first core deficit associated with developmental reading disorders- that of phonological awareness- is amenable to focused and remedial effort." p. 354

"Whether the core deficit in visual naming speed will prove as amenable to treatment as the phonological deficit has not been thoroughly investigated." p. 355

Questions or comments can be sent to: Sue Dungan

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