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Abstract
Children with a specific learning disability in reading/writing (LDRW) and/or language impairment (LI) are likely to have difficulties across all areas of academic achievement, as a great deal of teaching and learning depends on intact reading skill and linguistic communication. Despite a large number of studies examining academic difficulties among these groups, there has been minimal research investigating types of errors made on tests of academic achievement. The present study compared academic error types of children with LDRW (Group 1) and children with LI (Group 3) to two distinct demographically matched control groups (Groups 2 and 4) using the Kaufman Test of Educational Achievement–Third Edition (KTEA-3) error analysis system. Findings indicate that children in the LDRW group or LI group, on average, made a greater number of errors than their matched counterparts. Statistically significant differences, with moderate effect sizes, were found between examinees in the clinical groups and their respective matched control groups across several error categories. Some of the largest differences were found in the Written Expression and Oral Expression subtests. Most importantly, the patterns of errors made by LDRW and LI samples differed notably on the various tasks, providing new insights about these clinical samples.
To understand what one reads, it is crucial that children develop adequate skills in word reading and decoding, as well as language comprehension. Thus, children with reading difficulties may have weaknesses in one or more of these distinct skills. Decades of research examining reading disabilities and language impairments (LIs) have shown that the two disorders share a significant amount of overlapping characteristics. In fact, many researchers have proposed abandoning the distinction between reading disabilities and LIs (see Bishop & Snowling, 2004, for a thorough review of the evidence). Both disorders are characterized by delays in oral language development and underlying cognitive deficits in phonological processing (Pennington, 2008). Furthermore, neuroimaging studies have shown that individuals with reading disabilities and/or LIs exhibit similar patterns of neurobiological abnormalities in left-hemisphere perisylvian regions associated with reading and language, particularly the inferior frontal gyrus (Pennington, 2008). In addition, studies have shown that the two disorders have common genetic etiologies (Newbury et al., 2011).
Despite these similarities, there are also a number of differences between the two disorders. For instance, although many magnetic resonance imaging (MRI) studies have shown similar patterns of impairment, research has also revealed that reduced or reversed asymmetry in the cortical areas crucial for language development (i.e., planum temporale) is more likely to be associated with an LI than reading disabilities (Leonard et al., 2002). Moreover, research on the academic profiles of the two disorders has revealed that students with reading disabilities typically face greater challenges with word reading, whereas students with LIs tend to have more difficulty with oral language comprehension (Keenan, Betjemman, Wadsworth, DeFries, & Olson, 2006). Furthermore, students with a co-morbid LI and reading disability show greater difficulties on measures of cognitive reasoning and verbal ability than students with reading disability alone (Kim & Lombardino, 2013). Although these studies have increased our understanding of the similarities and differences of students with reading disabilities and LIs, they have not always led to specific interventions that differentiate instruction for individual students.
The purpose of the present study was to examine the types of academic errors made by students with a specific learning disability in reading/writing (LDRW) and those with an LI to inform the development of specific interventions to address these difficulties. We hypothesized that students with an LDRW or LI will exhibit significantly greater academic errors than their demographically matched counterparts. More specifically, we hypothesize that the LDRW group will have more errors on tasks of word reading and decoding, whereas students with LIs will demonstrate more errors on tasks of listening comprehension and oral expression. Both clinical groups will have more errors on tasks assessing phonological processing, reading comprehension, and written expression compared with the matched control groups. Finally, we hypothesize that there will be no significant difference between the clinical groups and their matched controls in the areas of mathematics.
Method
In the current study, we analyzed the specific errors made by students who have an LDRW (n = 67) with a matched control group, and those that have an LI (n = 59) with their own matched control on the Kaufman Test of Educational Achievement–3rd Edition (KTEA-3), using its norm-based error analysis system. The control groups were matched based on age, sex, parent educational level, and ethnicity (see Table 1). The error scores for different subtests were factor analyzed to produce conceptually meaningful factor scores. For example, error scores for both reading and listening were analyzed together, whereas written expression and oral expression were combined. The data for this study were acquired during the standardization validation process for the KTEA-3.
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Table 1. Demographics for the Experimental and Control Samples.
Results and Discussion
Independent-samples t tests were used to examine the differences across the various error scores within each matched sample (LDRW with matched control and LI with matched control; see Table 2). In both samples, results indicate that examinees in the clinical groups (LDRW and LI), on average, made a greater number of errors than their matched counterparts. Statistically significant differences, with moderate effect sizes, were found between examinees in the clinical groups and their respective matched control groups across several error categories. Most importantly, the patterns of errors made by LDRW and LI samples differed notably on the various tasks, providing new insights about these clinical samples. For example, as can be seen in Figure 1, in the area of word reading and decoding, the LDRW group demonstrated significantly greater errors compared to their matched control group on the error factors, Contextual Vowel Pronunciation and Letter Sound Knowledge, whereas the LI group differed from their control group on Intermediate Sound Knowledge. As expected, both groups performed significantly different from their matched controls on tasks of phonological processing, reading comprehension, and written expression. Interestingly, both clinical groups performed significantly different from their matched controls on tasks of listening comprehension and oral expression, which was notconsistent with our original hypothesis. Finally, in the area of mathematics, the LDRW group demonstrated significantly greater errors compared with their control group on the error factors of Math Calculation and Miscellaneous Math Concepts, whereas no differences were found between the LI group and their matched control group on any of the math error factors
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Table 2. Matched Group Independent-Samples t tests Between Clinical and Control Group on Error Factor Scores.
Figure 1. The flow chart consists of the four main hypotheses in the study. The pie charts demonstrate whether the hypotheses were met and by which groups. For example, although the first hypothesis is that only the LDRW group would be significantly different from their matched control in errors within Letter and Word Recognition, Nonsense Word Decoding, and Spelling, we see that there was one error category where the LI group had more errors than their matched control group, yet there was no significant differences between LDRW and their matched control. LDRW = learning disability in reading/writing; LI = language impairment.
The study showed that by systematically examining the patterns of errors made by students with disabilities on tests of reading, spelling, writing, and oral language, it is possible to enhance diagnostic procedures and to help identify appropriate educational interventions. More specifically, our results provide evidence that children with reading and/or writing difficulties and LIs exhibit distinct patterns of academic errors. These findings are consistent with research demonstrating that the two groups have distinct academic profiles (Keenan, Betjemman, Wadsworth, DeFries, & Olson, 2006). However, since this is one of the first studies of its kind, future research is needed before using academic error profiles for diagnostic purposes. To guide interventions, practitioners should consider patterns of errors that students with LDRW and/or LI exhibit on tests of academic achievement. For instance, our results indicate that a child with LDRW may require more individualized interventions to address vowel pronunciations that require context and basic letter-sound knowledge, whereas students with LI may need stronger support to help develop the second-wave of letter-sound learning (i.e., leaning consonant digraphs and blends). Nonetheless, it is important to note that practitioners should always examine each student’s individual errors as they may differ from their identified group. Future research is recommended to examine how these academic error types relate to cognitive profiles among these two groups.
Acknowledgements
The authors thank NCS Pearson for providing the standardization and validation data for the Kaufman Test of Educational Achievement–Third Edition (KTEA-3). Copyrights by NCS Pearson, Inc. used with permission. They also thank Alan and Nadeen Kaufman for their supervision of the comprehensive error analysis research program.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
References
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