Learning Disabled Readers Research Articles

Age-related differences in learning disabled and skilled readers’ working memory

This study determines whether age-related deficits in learning disabled (LD) readers’ working memory performance reflect delays in retrieval efficiency and/or storage capacity. The study compared LD and skilled readers’ working memory performance ( N=226) across four age groups (7, 10, 13, and 20) for phonological, visual-spatial, and semantic information under initial (non-cued), gain (cues that bring performance to an asymptotic level), and maintenance conditions (asymptotic conditions without cues). The important results were that LD readers’ working memory performance was inferior to skilled readers on verbal and visual-spatial working memory tasks across all age groups and these differences increased on gain and maintenance conditions when compared to initial conditions. These reading group differences remained when age, reading, and mathematics were partialed from the analysis. The results support a general capacity explanation of reading group differences that is not totally dependent on reading skill. These differences in capacity reflect demands placed on both the accessing of new information and the maintenance of old information that extend beyond the phonological system.

Working memory, short-term memory, speech rate, word recognition and reading comprehension in learning disabled readers: does the executive system have a role?

This study explored the contribution of two working memory systems (the articulatory loop and the central executive) and short-term memory to the word recognition and comprehension deficits of children with learning disabilities (LD). In Experiment 1, performance of LD, chronological age (CA)-matched, and reading level (RL)-matched children was compared on measures of articulation rate, short-term memory (STM), and working memory (WM). Experiment 2 included the same procedures as Experiment 1, except that WM tasks were administered under cued-recall conditions. The results indicated that (a) LD readers' STM and WM performance was inferior to CA-matched and RL matched readers when articulation speed (the articulatory system) was partialed from the analysis and (b) WM predicted word recognition and comprehension performance independent of the contribution of STM and articulatory rate. The results were interpreted as support for the notion that LD readers' poor word recognition and comprehension performance reflected deficits in a central executive system independent of their deficits in the articulatory loop.

Reading Comprehension and Working Memory in Learning-Disabled Readers: Is the Phonological Loop More Important Than the Executive System?

This investigation explores the contribution of two working memory systems (the articulatory loop and the central executive) to the performance differences between learning-disabled (LD) and skilled readers. Performances of LD, chronological age (CA) matched, and reading level-matched children were compared on measures of phonological processing accuracy and speed (articulatory system), long-term memory (LTM) accuracy and speed, and executive processing. The results indicated that (a) LD readers were inferior on measures of articulatory, LTM, and executive processing; (b) LD readers were superior to RL readers on measures of executive processing, but were comparable to RL readers on measures of the articulatory and LTM system; (c) executive processing differences remained significant between LD and CA-matched children when measures of reading comprehension, articulatory processes, and LTM processes were partialed from the analysis; and (d) executive processing contributed significant variance to reading comprehension when measures of the articulatory and LTM systems were entered into a hierarchical regression model. In summary, LD readers experience constraints in the articulatory and LTM system, but constraints mediate only some of the influence of executive processing on reading comprehension. Further, LD readers suffer executive processing problems nonspecific to their reading comprehension problems.

Cognitive processes as predictors of word recognition and reading comprehension in learning-disabled and skilled readers: Revisiting the specificity hypothesis.

This study examines how cognitive processes interrelate as well as predict learning-disabled (LD) readers' word recognition and reading comprehension performance. Correlations between phonological, orthographic, semantic, metacognitive, and working memory measures with reading performance were examined in LD and skilled readers ages 8 to 12 years. Important results were (a) LD readers were deficient on all cognitive processes compared with skilled readers, but these differences do not reflect IQ scores; (b) reading ability group differences emerged on a component composed primarily of working memory measures (referred to as g) as well as unique components, suggesting that these differences emerge on both general and specific (modular) processes; (c) g best predicts reading comprehension for both groups; and (d) phonological awareness best predicts skilled readers' pseudoword reading, whereas g best predicts LD readers' pseudoword performance. Overall, LD readers' information processing difficulties were described within a general working memory model that views such children as having difficulty accessing and coordinating both general and specific processes. Results suggest that the cognitive processes that contribute to reading deficits are best understood in the context of their combination with other operations rather than in isolation.

Cognitive processes as predictors of word recognition and reading comprehension in learning-disabled and skilled readers: Revisiting the specificity hypothesis.

Cognitive processes as predictors of word recognition and reading comprehension in learning-disabled and skilled readers: Revisiting the specificity hypothesis.

Learning disabled and average readers' working memory and comprehension: does metacognition play a role?

The present study investigates (a) whether learning disabled readers' working memory deficits that underlie poor reading comprehension are related to a general system, and (b) whether metacognition contributes to comprehension beyond what is predicted by working memory and word knowledge. To this end, performance between learning and disabled (N = 60) and average readers (N = 60) was compared on the reading comprehension, reading rate, and vocabulary subtests of the Nelson Skills Reading Test, Sentence Span test composed of high and low imagery words, and a Metacognitive Questionnaire. As expected, differences between groups in working memory, vocabulary, and reading measures emerged, whereas ability groups were statistically comparable on the Metacognitive Questionnaire. A within-group analysis indicated that the correlation patterns between working memory, vocabulary, metacognition, and reading comprehension were not the same between ability groups. For predicting reading comprehension, the metacognitive questionnaire best predicted learning disabled readers' performance, whereas the working memory span measure that included low-imagery words best predicted average achieving readers' comprehension. Overall, the results suggest that the relationship between learning disabled readers' generalised working memory deficits and poor reading comprehension may be mediated by metacognition.

Learning-disabled adolescents' comprehension of naturalistic narratives.

The ability of 20 normally achieving and 20 learning-disabled 8th- and 9th-grade readers to comprehend and interpret 2 fairly long and complex narratives, describing the emotional reactions of characters to realistic situations, was compared. The pattern of recall across story categories was similar for both groups. However, the learning-disabled readers not only recalled less overall than the normal readers, they were also less successful at differentiating levels of importance in the macrostructure of the stories. All students included less of the information needed to understand the characters' interactions in the more difficult story than in the easier story. Although normal readers could supply this information when directly probed for it, learning-disabled students were less successful in this respect, suggesting serious weaknesses in their ability to construct an appropriate situation model. Implications for the instruction of learning-disabled students are discussed.

ReadingisSeeing: Using Visual Response to Improve the Literary Reading of Reluctant Readers

This study compared the responses of two highly reluctant learning-disabled readers before and after they were helped to visualize story situations and events through visual art. These visual art procedures included the reading of illustrated books, the use of visual protocols, and the creation of symbolic story representations, illustrated books, collages, and picture maps regarding their reading. Data gathered from the students were subjected to ethnographic analysis, including preliminary and systematic domain searches, to reveal codes and themes. Data revealed that the use of visual art helped these two readers to begin enjoying reading, and to begin evoking and manipulating story worlds in their minds. The treatments encouraged the students not only to “see” what they were reading, but also to make other response moves involving emotional affect, connecting their own life to the literary experience, and the consideration of significance. Most importantly, perhaps, these students began to participate in the classroom community through their artwork.

Effects of Dynamic Testing on the Classification of Learning Disabilities: The Predictive and Discriminant Validity of the Swanson-Cognitive Processing Test (S-CPT)

This study assessed the criterion-related and discriminant validity of the Swanson-Cognitive Processing Test (S-CPT). The S-CPT is an individually administered standardized battery of information processing tasks that assess performance under initial (static) and dynamic testing (testing-the-limits) conditions. In Experiment 1, children's ( N = 61) performance on the S-CPT under initial and dynamic testing conditions was compared to the WISC-R in predicting performance on Reading and Mathematics subtests of the WRAT-R. Gain scores established during dynamic testing conditions were the best predictors of reading and mathematics performance (14% and 26% of the variance, respectively). In Experiment 2, 156 children with reading deficits and 35 skilled readers were compared on the S-CPT under static and dynamic testing conditions. As expected, skilled readers performed better than learning-disabled readers across all subtests, but the results were qualified when subgroups were analyzed. The cluster analysis indicated that approximately 25% of the sample with learning disabilities was misdiagnosed, and better reflected slow learners (poor readers) or instructionally responsive children. The results support the notion that dynamic assessment contributes significant variance in the prediction of academic achievement and that such assessment procedures discriminate the processing potential of children with reading disabilities from children with other types of learning problems.

Individual differences in working memory: A model testing and subgroup analysis of learning-disabled and skilled readers

This experiment compares two models of working memory as means of explaining the variance in skilled and learning-disabled (LD) readers' comprehension performance. The contrasting models are tested as to whether short-term memory (STM) tasks operate independently, or serve as a subset of working memory (WM). Correlational and confirmatory factor analyses tested the alternative models. For Experiment 1, memory processes were inferred from performance on Sentence Span, Concurrent, and Preload tasks. Individual differences in the relationship between memory and reading performance were studied by subgrouping skilled and LD readers. The results support a process model in which LD readers have weaker WMs than skilled readers, not because of poor reading skills, but because they have less WM capacity available for performing reading and nonreading tasks. Experiment 2 extended the model to other measures of WM. Taken together, these studies support two primary conclusions: (a) WM reflects a number of independent processes that coalesce onto a single factor, independent of STM; and (b) reading comprehension and components of WM operate on a continuum of independence to dependence as reading becomes more skilled.

Executive processing in learning-disabled readers

Three experiments determine whether memory difficulties experienced by learning-disabled readers may be attributable, in part, to executive processing. In Experiment 1, learning-disabled readers, matched to skilled readers on chronological age and reading-comprehension ability, were compared on the Concurrent Digit Span measure presented under high (6-digit) and low (3-digit) memory-load conditions as they concurrently sorted cards into verbal or nonverbal categories. Experiment 2 utilized the same task as Experiment 1, except that learning-disabled (LD) readers of low and average working-memory capacity were compared with skilled readers of average and high working-memory capacity. Both experiments clearly showed that LD readers' performance is depressed under high memory-load conditions. Experiment 2 also indicated that overall performance of non-learning-disabled (NLD) readers was predictable from LD readers, suggesting that ability-group differences are related to global processing efficiency rather than to isolated verbal and nonverbal systems. In Experiment 3, LD and NLD readers were compared on their ability to recall central and secondary information from base and elaborative sentences tasks under high- and low-effort encoding conditions. LD readers had significantly poorer secondary recall during high-effort encoding conditions when compared to skilled readers. Taken together, the results are discussed within a framework that views individual differences in reading comprehension as reflecting, in part, executive processing (i.e., resource monitoring) activities.

Naturalistic memory in learning-disabled and skilled readers

Three experiments compared learning-disabled and skilled readers' performance on naturalistic memory measures, as well as investigated the relationship between memory performance on everyday and laboratory tasks. In Experiment 1, the laboratory task (sentence span task) and everyday memory measures were correlated moderately for both ability groups. Compared to skilled readers, disabled readers performed poorly on the sentence span task, and were less likely than skilled readers to remember information related to common objects and consequential events. Disabled readers were also less likely to rely on external prompts to help them recall everyday information. Experiment 2 extended the previous findings to older subjects and found that the majority of significant correlations between the laboratory (word span task) and everyday memory tasks were isolated to disabled readers. When compared to chronological-age-matched subjects, disabled readers were inferior in recency performance on the laboratory (word span) and natural serial recall (e.g., recall of U.S. presidents) tasks. Experiment 3 showed that under conditions that facilitate item accessibility, ability group differences in recall were comparable. Taken together, the findings indicate that disabled readers' memory deficits are pervasive across naturalistic and laboratory measures at the younger age, but these deficits diminish for older students. Further, the deficits that occur at the older age are due to problems in accessing knowledge.

Verbal coding deficits in learning-disabled readers: A multiple stage model

This article reviews some selected literature, drawn from the last 10 years, suggesting that learning-disabled (LD) readers have functionallyindependent visual and verbal coding systems. The review focuses on studies where it has been shown that learning-disabled readers fail to effectively establish visual and verbal coding interconnections, which in turn impairs their episodic memory for visual information. It is hypothesized that this faulty interconnection is manifested by verbal codes failing to adequately provide an “additive” component to enhance the recall of visual information. The article reviews some data supporting this hypothesis, as well as extending the hypothesis by suggesting that a deficient lexical system may contribute to disabled readers' independent coding operations on a picture-naming task. The research is organized within a tentative model which assumes that there are at least three distinct information-processing stages (modality-specific, semantic, and lexical processing) that play an important role in disabled readers' processing of visual information.

Memory Subtypes in Learning Disabled Readers

This study assumes that learning disabled readers may be characterized by different patterns of memory dysfunction. To test this assumption, subgroups of LD readers were determined through a hierarchical cluster analysis, which included a memory classification battery of semantic, elaborative, and effortful encoding tasks. Eight subtypes of memory dysfunction were identified. One LD subtype, 8% of the sample, presented a normal profile; however, all subtypes were inferior to non-LD readers in composite scores reflecting elaboration and central-processing demands. Five subtypes (over 78% of the sample) demonstrated severe memory difficulties primarily with elaboration and high-effort encoding tasks when compared to the other subtypes. The results were generally consistent with memory-capacity theories suggesting that individual differences in recall are related to possessing (a) sufficient amount of structural resources (i.e., word knowledge base) to meet task demands, (b) sufficient supply of required capacity under high-effort encoding conditions, and (c) sufficient resource monitoring policy. The study provides external validation for classification of LD readers on psychometric measures according to patterns of memory performance.

What learning-disabled readers fail to retrieve on verbal dichotic tests: a problem of encoding, retrieval, or storage?

Three theoretical models were assessed as a framework for capturing learning-disabled readers' faulty word retrieval. To this end, learning-disabled and skilled readers were compared on verbal dichotic listening tasks for free recall and cued recall of word lists organized by semantic, phonemic, and structural features. The results indicated that disabled readers were comparable on free recall but were inferior to skilled readers on cued recall. No ability group differences were found for categorical and noncategorical recall intrusions during the cued recall phase. Cued recall performance was further analyzed for individual differences in memory trace structure (via the Tulving & Watkins, 1975, reduction method), ear asymmetry, and the allocation of attention to word features prior to cuing. Results indicated that during the cued recall phase, disabled readers' memory traces were inferior in structure to those of skilled readers, even though the two ability groups produced comparable symmetrical recall patterns for the ear presentations. Further, disabled readers had lower selective attention scores for the interhemispheric processing of information prior to cuing than did skilled readers. Taken together, the results suggest that, prior to cued recall, disabled readers suffer from attentional difficulties during interhemispheric processing, which in turn influences the structural formation of their memory trace.

Developmental Changes in LD Readers' Encoding Preferences

The present study addressed the question, “Do encoding preferences underlie disabled readers' recall deficiencies and, if so, what cognitive mechanisms influence these preferences?” The free recall of learning disabled readers, ages 8 and 10, was compared with that of nondisabled readers during directive and nondirective encoding conditions. The former training condition was implemented to assess the independent effects of semantic and nonsemantic encoding. Both ability groups were found to recall more semantically than nonsemantically organized items. Age and ability group differences emerged in recall, but not in retrieval organization. During the nondirective phase readers' encoding preference for categorically organized and unrelated items was assessed. Although no ability group differences emerged, disabled readers preferred to encode categorically organized items nonsemantically whereas nondisabled readers organized items by semantic features. Results, discussed in terms of mismatch between encoding and retrieval processes, semantic cohesiveness of item retrieval, and children's word knowledge base, question the popular notion that strategy training eliminates processing differences between ability groups.

Verbal-Coding Deficits in the Recall of Pictorial Information by Learning Disabled Readers: The Influence of a Lexical System

Based on a three-stage model of memory coding, comparisons were made between reading ability groups on their serial recall of pictorial information. In Experiment 1, learning disabled and skilled readers viewed pictures of low and high verbal codable shapes without names or with names either “matched” or “mismatched” with respect to the shape’s form. Regardless of the shape codability, both types of name-training conditions improved skilled readers’ recall, whereas disabled readers exhibited better recall for unnamed shapes. Experiment 2 compared the two ability groups on recall of shapes when name-training conditions involved labels low in meaningfulness. No ability group differences emerged. Taken together, the two experiments suggest that skilled readers’ interdependent coding operations are related to the activation of a semantic system from long-term memory. In contrast, disabled readers’ multiple coding operations represent difficulties in coordinating verbal information between two independent memory storages (i.e., short-term and long-term) as well as a bias for processing information through a visual route. In Experiment 3, learning disabled readers were divided into high (LD-HV) and low (LD-LV) vocabulary (lexical) subgroups. No significant difference in recall was found between skilled and LD-HV readers on the name-training condition. Both ability groups were superior in recall to the LD-L V readers. In contrast, the LD-L V readers were superior on the unnamed conditions when compared to the other ability groups. The results suggest that interdependent coding operations in disabled readers occur when their semantic memory system has access to highly developed lexical codes.

Verbal-Coding Deficits in the Recall of Pictorial Information by Learning Disabled Readers: The Influence of a Lexical System

Based on a three-stage model of memory coding, comparisons were made between reading ability groups on their serial recall of pictorial information. In Experiment 1, learning disabled and skilled readers viewed pictures of low and high verbal codable shapes without names or with names either “matched” or “mismatched” with respect to the shape’s form. Regardless of the shape codability, both types of name-training conditions improved skilled readers’ recall, whereas disabled readers exhibited better recall for unnamed shapes. Experiment 2 compared the two ability groups on recall of shapes when name-training conditions involved labels low in meaningfulness. No ability group differences emerged. Taken together, the two experiments suggest that skilled readers’ interdependent coding operations are related to the activation of a semantic system from long-term memory. In contrast, disabled readers’ multiple coding operations represent difficulties in coordinating verbal information between two independent memory storages (i.e., short-term and long-term) as well as a bias for processing information through a visual route. In Experiment 3, learning disabled readers were divided into high (LD-HV) and low (LD-LV) vocabulary (lexical) subgroups. No significant difference in recall was found between skilled and LD-HV readers on the name-training condition. Both ability groups were superior in recall to the LD-L V readers. In contrast, the LD-L V readers were superior on the unnamed conditions when compared to the other ability groups. The results suggest that interdependent coding operations in disabled readers occur when their semantic memory system has access to highly developed lexical codes.

The Effects of Organizational Dimension on Memory for Words in Learning-Disabled and Nondisabled Readers

This study determines whether residual recall differences between reading ability groups after a memory-training task on a sort/recall task reflect the dimensions of organizational processing. Within a theoretical framework that views memory organization as representing independent dimensions (i.e., integrative and elaborative), two experimental phases assessed learning-disabled and nondisabled readers' recall of word lists. For the first experimental phase, integrative condition, children were induced to sort and recall word lists by three separate features-semantic, phonemic, or orthographic. Age and ability group differences emerged in the free recall and organizational processing (i.e., selective attention to the organization of word features). For the second experimental phase, elaborative condition, children sorted familiar and unfamiliar word lists combining all three classes of organizational features (i.e., semantic, phonemic, orthographic) within each list. Although age-related effects occurred on free recall, clustering, and selective attention, no ability-group effects emerged. The results suggest that when compared to age-related nondisabled readers, learning-disabled readers adequately access word features organized by elaborative but not integrative dimensions. Four implications of the study are discussed.

Musical Differences in Learning-Disabled and Normal-Achieving Readers, Aged Seven, Eight and Nine

In the United States, learning-disabled children have been mainstreamed into general music classes where group instruction predominates without adequate evaluation of possible learning strengths and deficits. Three separate research projects have indicated that learning-disabled readers, aged seven, eight and nine, discriminate rhythm patterns similarly to matched normal- achieving readers but are unable to perform the same patterns in a similar manner. The two reading ability groups also differ at age seven and eight in tonal discrimination. The findings suggest that learning-disabled children may not be able to learn music in a class instructional setting as easily as their age-level peers. These exceptional learners need prior evaluation of input, integration and output capacities before being placed in learning situations where they will be unsuccessful.