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Author(s): |
Pamela Hook Ph.D. and Paul Macaruso Ph.D. |
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Reprinted with Permission From: |
International Dyslexia Association (info) |
Printed Date: Summer 2001
Date Posted on this Website: October 04 2002
Numerous research studies have shown that children with developmental dyslexia often present with an underlying phonological processing disorder (Lyon, 1995; Share & Stanovich, 1995). Problems in phonological processing are reported to occur both in low-level perceptual identification/discrimination of speech sounds, and at higher levels related to phonemic awareness (e.g., segmenting, blending and manipulating speech sounds). These higher order phonological processing skills are particularly important in learning to read an alphabetic orthography where sounds map on to print in a systematic way (Brady, 1997). Some have suggested that the weaknesses in phonological processing seen in children with dyslexia reflect a more general auditory processing disturbance (e.g., Farmer & Klein, 1995). Specifically, the claim is made that these children have difficulty processing the temporal characteristics of rapidly changing acoustic signals of any sort, including speech sounds and non-verbal auditory signals (Tallal, Miller, Jenkins & Merzenich, 1997). According to Tallal (1980), disturbances in auditory processing may contribute not only to problems in speech perception but also to weaknesses in developing phonemic awareness and learning and applying phonic reading strategies as seen in children with dyslexia.
Much of the evidence for a general auditory processing disorder in children with dyslexia comes from studies that ask children to make temporal order judgments for nonverbal tones presented at rapid rates. For example, Tallal (1980) found that children with dyslexia have difficulty determining the order of two computer-generated non-speech tones presented at short interstimulus intervals (around 300 ms or less) but not at longer' intervals. A general auditory processing disorder is said to underlie weaknesses seen in children with dyslexia in discriminating among consonant-vowel pairs (e.g., /ba/ and /da/) that mainly differ in the first 40 ms of the speech signal (Reed, 1989). Similar disturbances in auditory processing are reported in children with a broad range of language- leaming difficulties (Tallal et al., 1997).
Based on these findings, computer programs were developed to improve the auditory processing skills of children with spoken language disorders. For instance, in a pair of studies published in Science (Merzenich et al., 1996; Tallal et al., 1996), children with spoken language disorders participated in an intensive training program (more than 20 hours per week for four weeks) in which they listened to stories and engaged in language activities using acoustically modified speech. Consonant segments were elongated and made louder than the rest of the speech signal. The language activities targeted aspects of morphology, syntax and semantics. Modifications to the speech signal were designed to enhance speech perception in the context of the language activities. Other activities included audiovisual games requiring temporal order judgments for nonverbal tones and syllables. (e.g., Does "beh" occur first or second in "deh beh"?) After the training program, children showed significant improvements on tests of auditory temporal processing, speech discrimination, and on a variety of receptive language measures. Children presented with modified speech showed greater gains than a control group of children who participated in the same language activities but with natural, unmodified speech.
Following the Science articles, Scientific Leaming Corporation began publishing Fast ForWord computer programs (now called Fast ForWord Language) for children with language disorders. Although not originally designed for children with dyslexia, Scientific Leaming Corporation claims on its website that Fast ForWord (FFW) improves language and reading skills (Scientific Learning Corporation, 2001). Similar claims have appeared in the popular press. For instance, Newsweek (January 1, 2000) quotes Tallal as stating that "...90 percent of the kids who complete the program made 1.5 to two years of progress in reading skills (p. 64)." Based on the arguments of Tallal (1980), the programs should help facilitate reading acquisition because they sharpen phonological processing skills (including speech perception and phonemic awareness) which in turn benefit acquisition of phonic word attack strategies.
"Based on the arguments of Tallal, the [FFW] programs should help facilitate reading acquisition because they sharpen phonological processing skills (including speech perception and phonemic awareness) which in turn benefit acquisition of phonic word attack strategies." |
However, to date there has been relatively little published research demonstrating the benefits of FFW in improving reading (or spoken language) skills of children with dyslexia. In a recent review article, Gillam (1999) discusses a large-scale field study conducted by Tallal and her associates with children having a wide range of diagnoses (including specific language impairment, central auditory processing disorder, pervasive developmental delay, attention deficit disorder, and dyslexia). There are reported gains in various language skills but reading measures are not mentioned. To our knowledge the results of this study have not been published.
Contrary to previous reports, there has been a recent surge of studies suggesting that many children with dyslexia do not, in fact, show evidence of a general auditory processing disorder (Snowling, 2001), For instance, Nittrouer (1999) examined a group of poor readers who had typical phonological processing problems including limitations in phonemic awareness and verbal working memory, However, the poor readers did not differ from normal readers in their ability to recall the temporal sequences of nonspeech tones even when presented at brief, 20 ms interstimulus intervals, The groups also did not differ in their ability to discriminate between syllable pairs (e,g" /da/ versus /ta/) that are distinguished by rapidly changing consonant transitions in the speech signal, Similar results were obtained by Mody, Studdert-Kennedy and Brady (1997) for the phonetic distinction between /ba/ and /sa/. These findings raise questions as to whether the artificially slowed speech employed in FFW actually alters the way children process auditory information as claimed by Scientific Learning Corporation, or perhaps increases awareness of and attention to speech at the level of the phoneme,
In a recent study, we asked a group of children with dyslexia to participate in the FFW programs over the summer (Hook, Macaruso & Jones, in press). These programs are time intensive and involve children working at the computer for 100 minutes a day for a period of six to eight weeks. The children in our study were selected to have substantial weaknesses in phonemic awareness and word identification skills but adequate receptive language skills, Some difficulties were apparent in syntax which is a relatively common pattern seen in developmental dyslexia (e,g., Smith, Macaruso, Shankweiler & Crain, 1989). The FFW group showed significant gains in phonemic awareness and in the spoken language areas of speaking and syntax immediately after treatment, However, gains made in spoken language were not maintained over two years, and progress in phonemic awareness and reading mirrored gains made over two years by a longitudinal control group that did not participate in FFW. Thus, benefits of participation in FFW for reading and spoken language skills were minimal. Additionally, the FFW children were compared to a matched group of children who received Orton-Gillingham (OG) training one hour per day in a five week summer program. Both groups showed significant improvement immediately after treatment in phonemic awareness; however, only the OG group made significant progress in reading (i.e., word attack skills).
Overall, we found that participation in the FFW programs did not lead to any advantages in reading and spoken language compared to children receiving similar kinds of reading instruction (without FFW). Many established methods of reading instruction (such as Orton Gillingham) have had success in teaching children with dyslexia phonemic awareness and word attack skills. To recommend FFW as an alternative program, one needs to show that it contributes to stronger gains than established programs (Brady, Scarborough & Shankweiler, 1996). Taking into account the expense, effort and time commitment associated with the FFW program, it would seem worthwhile to participate in the program only if it leads to substantial improvements over other methods.
As we discovered, a main drawback for researchers attempting to evaluate the effectiveness of FFW is its lack of flexibility. Because FFW is sold and administered as a complete program, it is not possible to determine which specific aspects of the programs are beneficial for improving particular language skills. For instance, it is not possible to determine whether temporal order judgments for tones have any impact on phoneme awareness skills, or whether improvements on sentence comprehension tasks are tied to practice with language activities that emphasize syntactic or semantic processing. As it stands now the relative role of acoustically modified speech (e.g., lengthening the consonant transitions) in enhancing spoken language (and perhaps reading) skills in children with dyslexia cannot be established. It is certainly possible that the intensive nature of the FFW language activities combined with attention-grabbing altered speech and audiovisual games contributed to the immediate gains made by children in our study in the areas of spoken language skills including phonemic awareness. In any event, research has shown that reading programs which target phoneme awareness skills in isolation are likely not to be as effective as more traditional programs that combine work on phonemic awareness with specific training in sound/symbol correspondences and word identification skills (Ball & Blachman, 1991).
"Overall we found that participation in the FFW programs did not lead to any advantages in reading and spoken language compared to children receiving similar kinds of reading instruction (without FFW)." |
Another serious issue to consider in evaluating FFW is whether it is, in fact, well-suited as a form of treatment for children with reading difficulties. Although possibly effective in helping to improve spoken language skills in children with language disorders, FFW may not be particularly effective in remediation of reading difficulties related to word identification. As Miller and Tallal (1996) point out, dyslexia is often classified as a language-based learning disorder and that children with dyslexia usually have some concomitant oral language problems. Thus, they argue that children with dyslexia are likely to benefit from the types of programs found in FFW. However, Tallal et al. (1997) acknowledge that some children with dyslexia do not have significant disturbances in oral language. For instance, Tallal and Stark (1982) identified a subgroup of children with dyslexia who did not show receptive and expressive language difficulties. These children also did not display any weaknesses on a variety of verbal and non-verbal temporal processing tasks. In fact, there is a growing body of evidence (discussed above) indicating that many children with dyslexia do not show signs of general auditory processing deficits.
Therefore, caution should be taken in selecting which children might potentially benefit from participation in the FFW programs. Children who show significant limitations in phonemic awareness combined with more extensive spoken language disturbances than the children in our study might benefit from engaging in the FFW activities. Improvements in phonemic awareness are likely to occur along with perhaps some gains in reading comprehension related to enhancements in underlying spoken language skills. Whether there will be any progress in the areas of word attack skills and word identification remains to be seen.
Recently Scientific Learning Corporation has developed Fast ForWord Language to Reading which is designed to target reading skills more directly. The FFW Language to Reading programs intensify the consonant transitions but do not lengthen them. Because of this, participation in FFW Language is recommended prior to FFW Language to Reading. The latter programs contain activities tied directly to training sound/symbol correspondences. At this point the efficacy of FFW Language to Reading needs to be evaluated. In addition, it should be determined whether children experience greater gains in reading skills from participation in both FFW Language and FFW Language to Reading than from participation in FFW Language to Reading alone.
To conclude, we would like to highlight some precautions one should consider when promoting any treatment program for dyslexia. First, the program should be developed in the context of an empirically-tested theory of the processing impairments underlying the disorder. Care should be taken to specify any limitations with regards to rigorous outcomes research and, whenever possible, direct comparisons should be made to programs already validated as effective in treating the disorder. Additionally, it should be possible to reach some conclusions concerning which components of the program are truly beneficial in treating specific aspects of the disorder. Finally, it should be determined for which subgroups of individuals (with similar underlying impairments) the program is best suited.
References
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Brady, S. A. (1997). Ability to encode phonological representations: An underlying difficulty of poor readers. In B. Blachman (ed.), Foundations of reading acquisition and dyslexia: Implications for early intervention (pp. 21-47). Hillsdale, NJ: Lawrence Erlbaum Associates.
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