The use of nonword repetition as a test of phonological memory in children with Down syndrome

Recent research suggests a significant relationship between verbal short-term memory and normal language development. Although poor short-term memory and impaired language are features of Down syndrome there has been little investigation of the relationship between these functions in this population, and no studies have included the nonword repetition test devised by Gathercole and Baddeley on which much of the evidence from normal development is based. This study reports the use of nonword repetition with 33 children and teenagers with Down syndrome aged from 5 to 18 years, and investigates the relationship between this test and other memory and language measures. Word repetition was included as an indirect control for the perceptual and speech impairments often associated with this group. Words were repeated significantly more successfully than nonwords and both these tasks were sensitive to word length. Nonword repetition was significantly correlated with age, and when age and nonverbal cognitive ability were controlled, nonword repetition was significantly correlated with all other language-based memory measures, i.e. auditory digit span, word span, sentence repetition, and fluency, and also with memory for a sequence of hand movements, but not with memory for faces or a visual digit span task. There was also a significant relationship between nonword repetition and receptive vocabulary, language comprehension, and reading. When performance on the word repetition task was controlled in addition to age and nonverbal ability, significant correlations between nonword repetition and word span, sentence memory, hand movements, language comprehension, and reading remained. Fewer relationships between auditory digit span and these other measures were established; in particular, there was no association between digit span and the language and reading measures. Results suggest that nonword repetition is a reliable measure of phonological memory in Down syndrome and can predict language comprehension and reading ability.     

Individual Differences in the Inference of Word Meanings From Context: The Influence of Reading Comprehension, Vocabulary Knowledge, and Memory Capacity.

Two studies investigated the ability to use contextual information in stories to infer the meanings of novel vocabulary by 9-10-year-olds with good and poor reading comprehension. Across studies, children with poor reading comprehension were impaired when the processing demands of the task were greatest. In Study 2, working memory capacity was related to performance, but short-term memory span and memory for the literal content of the text were not. Children with poor reading comprehension were not impaired in learning novel vocabulary taught through direct instruction, but children with both weak reading comprehension and vocabulary were. Implications for the relation between vocabulary development and text comprehension are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relationship between visual memory function and lesions detected by magnetic resonance imaging after closed head injury.

45 patients (aged 16–73 yrs) with closed head injuries were followed up 6 mo postinjury with magnetic resonance imaging (MRI) and neuropsychological assessments. Ss were tested on visual and verbal measures of short-term memory and learning: pattern span, pattern learning, path span, path learning, digit span, and digit learning. Visual memory for patterns and paths was tested using a recall procedure. Compared with 22 controls (aged 15–70 yrs), Ss were significantly impaired on pattern span. Ss were also significantly impaired on measures of path learning and digit learning. Performance on the visual memory tasks was related to a rating of ventricular enlargement derived from MRI. It appears that diffuse damage remains of importance in predicting neuropsychological impairment in head injury. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in working memory and comprehension: A test of four hypotheses.

A relationship has consistently been found between measures of working memory and reading comprehension. Four hypotheses for this relationship were tested in 3 experiments. In the 1st 2 experiments, a moving window procedure was used to present the operation–word and reading span tasks. High- and low-span Ss did not differentially trade off time on the elements of the tasks and the to-be-remembered word. Furthermore, the correlation between span and comprehension was undiminished when the viewing times were partialed out. Exp 3 compared a traditional experimenter-paced simple word-span and an S-paced span in their relationship with comprehension. The experimenter-paced word-span correlated with comprehension, but the S-paced span did not. The results of all 3 experiments support a general capacity explanation for the relationship between working memory and comprehension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is "working memory capacity" just another name for word knowledge?

This study is concerned with whether the correlation between complex working memory spans and reading comprehension occurs because the complex spans reflect the capacity of a structural working memory that plays a causal role in comprehension or because a 3rd factor, word knowledge, plays a causal role in both the span tasks and comprehension. If the latter hypothesis is correct, the correlation between word span and reading comprehension should be large when span is tested with low-frequency words but should not occur when span is tested with very familiar words. 90 college students were tested on a simple and a complex version of the word span task with high- and low-frequency words. The Verbal Scholastic Aptitude Test (VSAT) was used as a measure of reading comprehension. The correlation between span and VSAT was somewhat higher when span was tested with low-frequency words, but was significant with both low- and high-frequency words. This suggests that both word knowledge and a content-free working memory play a causal role in the relationship between word span and higher level cognitive tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive deficits, learning disabilities, and WISC Verbal–Performance consistency.

Three experiments compared 52 10–11 yr olds with specific learning disabilities (LDs) with controls on several tests of information processing and memory. Results show that (a) LD children with a balanced WISC Verbal–Performance IQ showed some deficit in the semantic processing of auditory verbal material; this deficit was not shown by LDs having a Performance IQ at least 15 points higher than their Verbal IQ; (b) increasing rate of presentation in information processing tasks did not affect the LDs more than the controls; (c) although the LDs showed little or no deficit in auditory digit span, they showed large deficits in short-term memory (STM) tasks involving supraspan auditory messages. A possible causal relationship between the STM deficits and academic disabilities is discussed in terms of an inability of the STM maintenance system to deal with overload. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simple and complex word spans as measures of working memory capacity.

Five experiments investigated the effects of word length in simple word span tasks and complex operation and reading span tasks and the relationship between these tasks and reading comprehension. The 1st 2 experiments showed word length effects using both simple and complex memory span tasks and that both simple and complex span tasks correlated with reading comprehension. In the 3rd experiment, articulatory suppression did not eliminate word length effects. The final experiments showed that articulatory suppression eliminated the effect of word length when words were sampled with replacement from small fixed pools but not when sampled without replacement from a large pool. The word pool effects were not a result of concreteness of the words. It is concluded that the reading span does not measure a working memory specific to reading. Further, in immediate memory experiments, repeating words from trial to trial may lead to a more limited coding than is used with nonrepeated words. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Children's Reading Comprehension Ability: Concurrent Prediction by Working Memory, Verbal Ability, and Component Skills.

The authors report data from a longitudinal study that addresses the relations between working memory capacity and reading comprehension skills in children aged 8, 9, and 11 years. At each time point, the authors assessed children's reading ability, vocabulary and verbal skills, performance on 2 working memory assessments (sentence-span and digit working memory), and component skills of comprehension. At each time point, working memory and component skills of comprehension (inference making, comprehension monitoring, story structure knowledge) predicted unique variance in reading comprehension after word reading ability and vocabulary and verbal ability controls. Further analyses revealed that the relations between reading comprehension and both inference making and comprehension monitoring were not wholly mediated by working memory. Rather, these component skills explained their own unique variance in reading comprehension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

''Best clinical practice'': assessment of processes of care and of outcomes in the US Military Health Services System

The functioning of working memory in schizophrenic patients according to Baddeley's model was examined in two complementary experiments. Experiment 1 comprised 27 patients and their controls, matched in age and level of education. Of this pool, 20 pairs participated also in Experiment 2. Digit span, reading rate, and immediate serial recall assessed the functioning of the phonological loop. Corsi and pattern span tasks assessed the capacity of visuo-spatial memory. The central executive's ability to monitor two concurrent tasks was evaluated in a dual task paradigm, and its capacity to control action in a random generation task. A preliminary set of analyses showed that the patients' performances were reduced in all tasks explored, except in digit span. This initial pattern changed consistently after controlling for reading rate. While slow and fast reading patients were comparable in demographic and clinical criteria, slow reading patients showed impaired performance in all tasks, whereas fast reading patients exhibited reduced performance in visuo-spatial tasks and in the random generation task only. The state of functioning of working memory in schizophrenia appears, therefore, to vary consistently among the components of the model and is markedly impaired in slow reading patients. The implications of slowness are discussed.     

Phonological short-term memory and new word learning in children.

Sixty-five 5-year old children participated in 4 experimental tasks of word learning that varied systematically in the amounts of phonological and nonphonological learning required. Measures of the children's performances on 2 measures of phonological memory (digit span and nonword repetition), vocabulary knowledge, and nonverbal ability were also obtained. Learning of the sound structures of new words was significantly, and to some degree independently, associated with aspects of both phonological memory skill and vocabulary knowledge. Learning of pairs of familiar words was linked with current vocabulary knowledge, although not with phonological memory scores. The findings suggest that both existing lexical knowledge and phonological short-term memory play significant roles in the long-term learning of the sounds of new words. The study also provides evidence of both shared and distinct processes contributing to nonword repetition and digit span tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The structure of precocious reading ability.

The purpose of this study was to describe the cognitive correlates of precocious reading achievement and to identify the structure of individual differences in reading subskill patterns that are compatible with precocious achievement. Several oral reading tasks and selected subtests from the Wechsler Intelligence Scale for Children-Revised were administered to 87 postkindergarten children whose Peabody Individual Achievement Test reading comprehension scores ranged from the second- to the fifth-grade level. Parents provided information about the children's reading histories. Factor analysis of 11 reading subskill scores yielded results consistent with a hierarchical modification of the hypothesized model. Three specific factors—Speed, Decoding Rule Use, and Graphic Precision—varied independently of superordinate differences in General Ability. Verbal ability, letter-naming speed, and forward and backward digit span each correlated moderately with one or more reading factors. Many aspects of the results were consistent with findings from studies of average, disabled, and autistic/hyperlexic readers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in working memory: Introduction to the special section.

This special section includes a set of 5 articles that examine the nature of inter- and intraindividual differences in working memory, using working memory span tasks as the main research tools. These span tasks are different from traditional short-term memory spans (e.g., digit or word span) in that they require participants to maintain some target memory items (e.g., words) while simultaneously performing some other tasks (e.g., reading sentences). In this introduction, a brief discussion of these working memory span tasks and their characteristics is provided first. This is followed by an overview of 2 major theoretic issues that are addressed by the subsequent articles—(a) the factors influencing the inter- and intraindividual differences in working memory performance and (b) the domain generality versus domain specificity of working memory—and also of some important issues that must be kept in mind when readers try to evaluate the claims regarding these 2 theoretical issues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Short-term memory processes in children with reading and arithmetic learning disabilities.

Examined the role of phonemic coding in short-term memory in 45 children with a reading disability, 38 children with a specific arithmetic disability, and 89 normal children, as measured by the Wide Range Achievement Test. Ss, aged 7–13 yrs, were administered a series of tasks that involved the visual or auditory presentation of rhyming and nonrhyming letters and either an oral or a written response. Younger Ss (7–8 yrs) with a reading disability did not show any difference between the recall of nonrhyming and rhyming letters, whereas normal Ss of the same age did. Older reading-disabled Ss (aged 9–23 yrs), like their normal counterparts, had significantly poorer recall of rhyming as opposed to nonrhyming letters. However, their overall levels of performance were significantly lower than normals. The same pattern was found with Ss with arithmetic disabilities for the visual presentation of stimuli. For the auditory presentation of stimuli, the performance of Ss with arithmetic disabilities resembled that of normals, except at the youngest ages. Whereas a deficiency in phonological coding may characterize younger children with learning disabilities, older children with learning disabilities appear to use a phonemic code but have a more general deficit in short-term memory. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of accelerated reading rate on memory for text.

Based on the finding that increasing stimulus presentation rate can increase short-term memory (STM) span, reading rate was accelerated in a series of experiments that demonstrated substantial gains in reading accuracy and comprehension. The present investigation tested the hypothesis that comprehension gains in fast-paced reading are attributable primarily to changes in STM functioning. A series of standard STM-sensitive tasks were administered in both self-paced and fast-paced reading conditions. The magnitude and relative specificity of effects evident in fast-paced reading confirmed the hypothesis. Several alternative hypotheses were rejected. These findings provide strong support for a causal role for STM function in text processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decomposing the relation between Rapid Automatized Naming (RAN) and reading ability.

The Rapid Automatized Naming (RAN) test involves rapidly naming sequences of items presented in a visual array. RAN has generated considerable interest because RAN performance predicts reading achievement. This study sought to determine what elements of RAN are responsible for the shared variance between RAN and reading performance using a series of cognitive tasks and a latent variable modelling approach. Participants performed RAN measures, a test of reading speed and comprehension, and six tasks, which tapped various hypothesised components of the RAN. RAN shared 10% of the variance with reading comprehension and 17% with reading rate. Together, the decomposition tasks explained 52% and 39% of the variance shared between RAN and reading comprehension and between RAN and reading rate, respectively. Significant predictors suggested that working memory encoding underlies part of the relationship between RAN and reading ability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Depression in multiple sclerosis: Relationship to working memory capacity.

Recent research has shown that depression in multiple sclerosis (MS) is associated with deficits on cognitively demanding tasks. One explanation for this relationship is that depressed NIS patients may have reduced working memory capacity. The present study was designed to test this hypothesis. Depressed NIS patients were compared with nondepressed MS patients and nondepressed healthy controls on a task of working memory capacity (reading span) and a short-term memory task not taxing working memory capacity (word span). In support of the capacity-reduction model, compared with the nondepressed groups, depressed MS patients performed significantly worse on reading span but not on word span. Additionally, reading span was significantly correlated with capacity-demanding tasks shown to be impaired in depressed NIS patients in previous reports. Results suggest that depressed MS patients are characterized by limited working memory capacity and that the central executive component of the working memory system may be most affected. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Information processing by school-age children with specific language impairment: evidence from a modality effect paradigm

School-age children with specific language impairment (SLI) and age-matched controls were tested for immediate recall of digits presented visually, auditorily, or audiovisually. Recall tasks compared speaking and pointing response modalities. Each participant was tested at a level that was consistent with her or his auditory short-term memory span. Traditional effects of primacy, recency, and modality (an auditory recall advantage) were obtained for both groups. The groups performed similarly when audiovisual stimuli were paired with a spoken response, but children with SLI had smaller recency effects together with an unusually poor recall when visually presented items were paired with a pointing response. Such results cannot be explained on the basis of an auditory or speech deficit per se, and suggest that children with SLI have difficulty either retaining or using phonological codes, or both, during tasks that require multiple mental operations. Capacity limitations, involving the rapid decay of phonological representations and/or performance limitations related to the use of less demanding and less effective coding and retrieval strategies, could have contributed to the working memory deficiencies in the children with SLI.     

Predictive ability of the General Ability Index (GAI) versus the Full Scale IQ among gifted referrals.

The General Ability Index (GAI) is a composite ability score for the Wechsler Intelligence Scale for Children—Fourth Edition (WISC–IV) that minimizes the impact of tasks involving working memory and processing speed. The goal of the current study was to compare the degree to which the Full Scale IQ (FSIQ) and the GAI predict academic achievement in math and reading among a group of 88 children tested for gifted programming. All students had significant variability among their index scores on the WISC–IV. Whereas both the FSIQ and GAI significantly predicted standardized achievement test scores in reading and math, the FSIQ explained more of the variance. In sequential regression analyses, both working memory and verbal comprehension scores explained significant, unique variance in reading and math scores. However, measures of processing speed and perceptual reasoning did not account for significant amounts of variance in achievement scores over and above measures of working memory and verbal comprehension. The inclusion of working memory scores in calculation of the FSIQ appears to account for the difference in prediction between the FSIQ and the GAI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A new tool for measuring and understanding individual differences in the component processes of reading comprehension.

We propose a new measure of individual differences in reading comprehension ability that is theoretically motivated, is easy to administer, and that has high predictive power. Participants read 3-sentence paragraphs that describe the relations among a set of real and artificial terms, and then they respond to true–false statements that assess their ability to access and integrate long-term memory knowledge with text information, to make text-based inferences, and to recall text. The components of our task predict performance on a test of global reading comprehension and on a range of specific comprehension tests, each of which draws more heavily on one particular component. Our task is better at predicting reading comprehension than is a typical working memory span task and has the potential for advancing researchers' understanding and measurement of a range of linguistic and cognitive tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)