Rebecca S. Betjemann

Reading Comprehension Tests Vary in the Skills They Assess: Differential Dependence on Decoding and Oral Comprehension.

Comprehension tests are often used interchangeably, suggesting an implicit assumption that they are all measuring the same thing. We examine the validity of this assumption by comparing some of the most popular reading comprehension measures used in research and clinical practice in the United States: the Gray Oral Reading Test (GORT), the two assessments (retellings and comprehension questions) from the Qualitative Reading Inventory (QRI), the Woodcock–Johnson Passage Comprehension subtest (WJPC), and the Reading Comprehension test from the Peabody Individual Achievement Test (PIAT). Modest intercorrelations among the tests suggested that they were measuring different skills. Regression analyses showed that decoding, not listening comprehension, accounts for most of the variance in both the PIAT and the WJPC; the reverse holds for the GORT and both QRI measures. Large developmental differences in what the tests measure were found for the PIAT and the WJPC, but not the other tests, both when development was measured by chronological age and by word reading ability. We discuss the serious implications for research and clinical practice of having different comprehension tests measure different skills and of having the same test assess different skills depending on developmental level.

Etiology and neuropsychology of comorbidity between RD and ADHD: the case for multiple-deficit models.

INTRODUCTION Attention-deficit/hyperactivity disorder (ADHD) and reading disability (RD) are complex childhood disorders that frequently co-occur, but the etiology of this comorbidity remains unknown. METHOD Participants were 457 twin pairs from the Colorado Learning Disabilities Research Center (CLDRC) twin study, an ongoing study of the etiology of RD, ADHD, and related disorders. Phenotypic analyses compared groups with and without RD and ADHD on composite measures of six cognitive domains. Twin analyses were then used to test the etiology of the relations between the disorders and any cognitive weaknesses. RESULTS Phenotypic analyses supported the hypothesis that both RD and ADHD arise from multiple cognitive deficits rather than a single primary cognitive deficit. RD was associated independently with weaknesses on measures of phoneme awareness, verbal reasoning, and working memory, whereas ADHD was independently associated with a heritable weakness in inhibitory control. RD and ADHD share a common cognitive deficit in processing speed, and twin analyses indicated that this shared weakness is primarily due to common genetic influences that increase susceptibility to both disorders. CONCLUSIONS Individual differences in processing speed are influenced by genes that also increase risk for RD, ADHD, and their comorbidity. These results suggest that processing speed measures may be useful for future molecular genetic studies of the etiology of comorbidity between RD and ADHD.

Comprehending the Gray Oral Reading Test without Reading It: Why Comprehension Tests Should Not Include Passage-Independent Items.

We examined the validity of the comprehension component of the Gray Oral Reading Test (GORT; Wiederholt & Bryant, 1992, 2001) by assessing whether reading really is required to answer its questions. The extent to which GORT questions are passage independent was assessed by having participants answer them without reading the passages. Most questions had passageless accuracies above chance. Furthermore, the best predictor of how well a child given normal GORT administration answered a question was not how well the child read the passage but rather how well the question could be answered without reading. Analyses comparing passage-dependent and passage-independent items showed: (a) passage-independent items are not sensitive to reading disability, and (b) passage-independent items do not correlate with performance on other comprehension tests. We conclude that the GORT Comprehension Score lacks both content validity and concurrent validity and that the field of comprehension assessment needs to be more concerned about the passage independence of items.

Reading comprehension in children with ADHD: cognitive underpinnings of the centrality deficit.

We examined reading comprehension in children with ADHD by assessing their ability to build a coherent mental representation that allows them to recall central and peripheral information. We compared children with ADHD (mean age 9.78) to word reading-matched controls (mean age 9.89) on their ability to retell a passage. We found that even though children with ADHD recalled more central than peripheral information, they showed their greatest deficit, relative to controls, on central information—a centrality deficit (Miller and Keenan, Annals of Dyslexia 59:99–113, 2009). We explored the cognitive underpinnings of this deficit using regressions to compare how well cognitive factors (working memory, inhibition, processing speed, and IQ) predicted the ability to recall central information, after controlling for word reading ability, and whether these cognitive factors interacted with ADHD symptoms. Working memory accounted for the most unique variance. Although previous evidence for reading comprehension difficulties in children with ADHD have been mixed, this study suggests that even when word reading ability is controlled, children with ADHD have difficulty building a coherent mental representation, and this difficulty is likely related to deficits in working memory.

Phonological and Semantic Priming in Children with Reading Disability.

Lexical priming was assessed in children with reading disability (RD) and in age-matched controls (M= 11.5 years), in visual and auditory lexical decision tasks. In the visual task, children with RD were found to have deficits in semantic (SHIP-BOAT), phonological/graphemic (GOAT-BOAT), and combined (FLOAT-BOAT) priming. The same pattern of semantic priming deficits also occurred in auditory lexical decisions, suggesting that the semantic deficits are not confined to reading. Children with RD also showed less priming than reading-age matched controls, suggesting that their priming deficits are not simply due to lower reading level but are due to the reading disability in particular. These semantic deficits may contribute to both the word reading and the comprehension problems seen in children with RD.

Choice of Reading Comprehension Test Influences the Outcomes of Genetic Analyses

Does the choice of test for assessing reading comprehension influence the outcome of genetic analyses? A twin design compared two types of reading comprehension tests classified as primarily associated with word decoding (RC-D) or listening comprehension (RC-LC). For both types of tests, the overall genetic influence is high and nearly identical. However, the tests differed significantly in how they covary with the genes associated with decoding and listening comprehension. Although Cholesky decomposition showed that both types of comprehension tests shared significant genetic influence with both decoding and listening comprehension, RC-D tests shared most genetic variance with decoding, and RC-LC tests shared most with listening comprehension. Thus, different tests used to measure the same construct may manifest very different patterns of genetic covariation. These results suggest that the apparent discrepancies among the findings of previous twin studies of reading comprehension could be due at least in part to test differences.