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This study examined the influence of phonological memory and rapid naming on the development of letter knowledge. Participants were 77 Dutch children, who were followed from the start of their first kindergarten year (mean age 4 years 6.8 months) to the end of their second kindergarten year. Phonological memory was assessed by a nonword repetition test and a sentence repetition test. Rapid naming involved object naming. The study revealed found a substantial effect of phonological memory on the acquisition of letter knowledge that was particularly related to the ability to repeat nonwords. Vocabulary knowledge did not have an independent effect on letter learning after phonological memory was controlled. The study also showed a small effect of rapid naming on the acquisition of letter knowledge that was independent of the effect of phonological memory. Finally, the study also provided further evidence for a specific relation between phonological memory and vocabulary acquisition.

The influence of phonological memory and rapid naming on the development of letter knowledge was examined. A major finding of the study was that individual differences in nonword repetition, assumed to reflect phonological memory, had a specific effect on the acquisition of letter knowledge.

This study used a nonreferred sample of twins to contrast the performance of individuals with reading disability (RD; n = 93), attention-deficit/hyperactivity disorder (ADHD; n = 52), RD and ADHD (n = 48), and neither RD nor ADHD (n = 121) on measures of phoneme awareness (PA) and executive functioning (EF). Exploratory factor analysis of the EF measures yielded underlying factors of working memory, inhibition, and set shifting. Results revealed that ADHD was associated with inhibition deficits, whereas RD was associated with significant deficits on measures of PA and verbal working memory. The RD + ADHD group was most impaired on virtually all measures, providing evidence against the phenocopy hypothesis as an explanation for comorbidity between RD and ADHD. [ABSTRACT FROM AUTHOR]

Reading disability (RD), or dyslexia, is a common heterogeneous syndrome with a large genetic component. Several studies have consistently found evidence for a quantitative-trait locus (QTL) within the 17 Mb (14.9 cM) that span D6S109 and D6S291 on chromosome 6p21.3-22. To characterize further linkage to the QTL, to define more accurately the location and the effect size, and to identify a peak of association, we performed Haseman-Elston and DeFries-Fulker linkage analyses, as well as transmission/disequilibrium, total-association, and variance-components analyses, on 11 quantitative reading and language phenotypes. One hundred four families with RD were genotyped with a new panel of 29 markers that spans 9 Mb of this region. Linkage results varied widely in degree of statistical significance for the different linkage tests, but multipoint analysis suggested a peak near D6S461. The average 6p QTL heritability for the 11 reading and language phenotypes was 0.27, with a maximum of 0.66 for orthographic choice. Consistent with the region of linkage described by these studies and others, there was a peak of transmission disequilibrium with a QTL centered at JA04 (chi2=9.48; empirical P=.0033; orthographic choice), and there was strong evidence for total association at this same marker (chi2=11.49; P=.0007; orthographic choice). Although the boundaries of the peak could not be precisely defined, the most likely location of the QTL is within a 4-Mb region surrounding JA04.

Children with reading deficits perform more slowly than normally-achieving readers on speed of processing measures, such as rapid naming (RN). Although rapid naming is a well-established correlate of reading performance and both are heritable, few studies have attempted to assess the cause of their covariation. Measures of rapid naming (numbers, colors, objects, and letters subtests), phonological decoding, orthographic choice, and a composite variable (DISCR) derived from the reading recognition, reading comprehension, and spelling subtests of the Peabody Individual Achievement Test were obtained from a total of 550 twin pairs with a positive school history of reading problems. Basic DeFries and Fulker (DF) multiple regression models for the analysis of selected twin data confirmed the heritable nature of phonological decoding, orthographic choice, DISCR, and rapid-naming composites. Bivariate DF models were employed to examine the extent to which deficits in the three reading-related measures covary genetically with rapid naming. Significant bivariate heritability estimates for each of the reading measures with the numbers and letters rapid-naming composite were also obtained. As expected, univariate sib-pair linkage analyses indicated the presence of a quantitative trait locus (QTL) on chromosome 6p21.3 for phonological decoding and orthographic choice deficits. Bivariate linkage analyses were then conducted to test the hypothesis that this QTL for reading difficulties is pleiotropic for slower performance on RN tasks. The results obtained from these analyses did not provide substantial evidence that the 6p QTL for reading difficulties has significant effects on rapid naming; however, larger samples would be required to test this hypothesis more rigorously.

Linkage analysis has localized a gene influencing specific reading disability (dyslexia) to 6p21.3. The myelin oligodendrocyte glycoprotein (MOG) gene, which maps to this region, was selected as a candidate. Myelin oligodendrocyte glycoprotein is a membrane protein, a member of the immunoglobin superfamily, that is found on the outermost lamellae of mature myelin. Although the exact function of this protein is unknown, its presence in the central nervous system and the hypothesized relationship between dyslexia and temporal processing rate as well as a suggested relationship with intelligence made this gene a candidate for dyslexia. Analysis of the coding exons and adjacent splice sites in a subset of 22 children with dyslexia from 10 sibships found a missense mutation in exon 4 in 2 of the sibships. This change from the published sequence also occurred in 86 of 96 random controls, making it considerably less frequent in this small sample of individuals with dyslexia. Subsequent typing of this single nucleotide polymorphism (SNP) in 74 nuclear families in which at least one child had reading disability showed no significant difference in frequency from the controls, however. Sib-pair linkage analysis with these families did not show significant linkage with the SNP nor with a separate polymorphic dinucleotide repeat marker in the MOG gene (MOG31/32), but association analysis identified two alleles of MOG31/32 that were associated with reading disability phenotypes with a low level of significance. Thus, although alleles in the MOG gene may be in linkage disequilibrium with a locus that contributes to reading disability, it is unlikely that the MOG gene itself is involved.

The double-deficit hypothesis (Wolf, M. and Bowers, P.G. (1999) The double-deficit hypothesis for the developmental dyslexias. Journal of Educational Psychology, 91, 415-438) proposes that deficits in phonological processing and rapid automatized naming (RAN) are separable sources of reading dysfunction. Further, the double-deficit hypothesis predicts that the presence of deficits in both phonological processing and RAN have an additive negative influence on reading performance above and beyond that of a single deficit. The purpose of this study was to examine the additive nature of phonological awareness (PA)- and RAN-deficits on written language skill in children with reading disabilities (RD). Concurrent relationships between PA, RAN, and written language skills were examined in 476 children with RD, ranging in age from 8 to 18 years of age. Hierarchical regression analysis revealed that PA and RAN skill have an additive effect on a majority of the reading and spelling measures. When participants were classified into three deficit subtypes based on the double-deficit model (i.e. phonological-, rate-, and double-deficit), comparisons across the subtypes confirmed that individuals with double-deficits performed below the single-deficit groups on both subtyping variables (RAN and PA) and all measures of written language. When the double- and single-deficit groups were matched on the subtyping variable (i.e. double- and rate-deficit groups matched on RAN and double- and phonological-deficit groups matched on PA) differences between the double- and rate-deficit groups remained in non-word reading, whereas differences between the double- and phonological-deficit groups remained in timed word recognition and reading comprehension. These results support an additive model in which RAN-deficits primarily affect tasks that require speeded/fluent response, and PA-deficits primarily affect tasks that emphasize phonological processing skill. Results are also presented that illustrate several statistical problems associated with the formation of deficit groups by dichotomizing the RAN and PA variables.

Data from identical and fraternal twins were analyzed to estimate the proportions of genetic and environmental influences on group deficits in accuracy and, when available, speed for printed word recognition and for related skills in phonological decoding (PD), orthographic coding (OC), and phoneme awareness (PA). In addition, bivariate genetic analyses were employed to estimate the degree of common genetic influence on group deficits across these different reading and language skills. About half of the group deficits in each of the skills were due to genetic influences, and the genetic origins were largely shared among the measures (r(g) = .53 - .99), except for those between OC and PA (r(g) = .28 - .39). Implications of the results are discussed for models of reading disability and remediation.

It takes a relatively long time for new nursing graduates to become oriented and comfortable with work routines on the nursing unit. To address the problem, the authors formed a partnership among three educational programs and three hospitals. This article describes a 900-hour residency program for senior baccalaureate nursing students to ease their transition into the role of beginning-level staff nurse in an acute-care setting. The benefits to the hospitals were decreased orientation time, less turnover in staff (50% at 2 years), and lower recruitment costs.

During leptin signaling, each of the phosphorylated tyrosine residues on the long form of the leptin receptor (LRb) mediates distinct signals. Phosphorylated Tyr(1138) binds STAT3 to mediate its tyrosine phosphorylation and transcriptional activation, while phosphorylated Tyr(985) binds the tyrosine phosphatase SHP-2 and reportedly mediates both activation of ERK kinases and inhibition of LRb-mediated STAT3 activation. We show here that although mutation of Tyr(985) does not alter STAT3 signaling by erythropoietin receptor-LRb (ELR) chimeras in transfected 293 cells at short times of stimulation, this mutation enhances STAT3 signaling at longer times of stimulation (>6 h). These data suggest that Tyr(985) may mediate feedback inhibition of LRb signaling by an LRb-induced LRb inhibitor, such as SOCS3. Indeed, SOCS3 binds specifically to phosphorylated Tyr(985) of LRb, and SOCS3 fails to inhibit transcription by ELR following mutation of Tyr(985), suggesting that SOCS3 inhibits LRb signaling by binding to phosphorylated Tyr(985). Additionally, overexpression of SOCS3, but not SHP-2, impairs ELR signaling, and the overexpression of SHP-2 blunts SOCS3-mediated inhibition of ELR signaling. Thus, our data suggest that in addition to mediating SHP-2 binding and ERK activation during acute stimulation, Tyr(985) of LRb mediates feedback inhibition of LRb signaling by binding to LRb-induced SOCS3.

Two hundred second- to fifth-grade students (aged approximately 7 to 11 years) spent 29 h in a computer-assisted remedial reading program that compared benefits from accurate, speech-supported reading in context, with and without explicit phonological training. Children in the "accurate-reading-in-context" condition spent 22 individualized computer hours reading stories and 7 small-group hours learning comprehension strategies. Children in the "phonological-analysis" condition learned phonological strategies in 7 small-group hours, and divided their computer time between phonological exercises and story reading. Phonologically trained children gained more in phonological skills and untimed word reading; children with more contextual reading gained more in time-limited word reading. Lower level readers gained more, and benefited more from phonological training, than higher level readers. In follow-up testing, most children maintained or improved their levels, but not their rates, of training gains. Phonologically trained children scored higher on phonological decoding, but children in both conditions scored equivalently on word reading., (Copyright 2000 Academic Press.)

To test the hypothesis that the genetic etiology of reading disability differs as a function of IQ, composite reading performance data from 223 pairs of identical twins and 169 pairs of same-gender fraternal twins in which at least one member of each pair was classified with reading disability were subjected to multiple regression analysis (DeFries & Fulker, 1985, 1988). In the total sample, heritability of the group deficit in reading performance (h(g)2) was .58 (+/- .08). However, when the basic regression model was fitted separately to data from twin pairs with average Wechsler (1974, 1981) full scale IQ scores below 100 or 100 and above, resulting estimates of h(g)2 were .43 and .72, respectively, a significant difference (p < or = .03, one-tailed). The results of fitting extended regression models to reading performance and continuous IQ data provide evidence that the genetic etiology of reading disability differs as a linear function of IQ (p < or = .007, one-tailed). These results suggest that IQ is relevant for the diagnosis of reading disability and that environmental influences may be more salient as a cause of reading difficulties in children with lower IQ scores.

One hundred twenty-two second- to fifth-grade (7- to 11-year-old) children with reading difficulties studied phonological awareness with or without explicit attention to articulation and with or without manipulation of sounds. They all studied identical phonics and read stories on the computer with speech and decoding support for difficult words. Regular-instruction controls received regularly scheduled language-arts or reading activities. After 40 h of training, children in all three trained conditions outperformed controls on all tests except math. Conditions that manipulated sounds showed advantages over the condition without explicit practice manipulating sounds, but only on the two measures of phonological awareness. Articulatory awareness training yielded no unique benefits during this training period. Individual differences in response to treatment related to initial levels of phonological awareness, naming speed, IQ, and grade. The similar outcomes of the three conditions suggest that specific variations in good phonological training may be less important than once thought for most children with reading difficulties., (Copyright 1999 Academic Press.)

Benzalkonium chloride (BC) is an unreliable disinfectant. A matched case-control study and environmental investigation were conducted to determine the cause of and risk factors for a cluster of postinjection abscesses at a private medical clinic where BC was used as a disinfectant. Twenty-eight case-patients who had an abscess at the injection site were matched with 126 control patients who had received an intramuscular injection at the clinic on the same day. Risk factors for abscess development in a multivariable logistic model were corticosteroid injection and being female. All case-patients had received a corticosteroid injection from a multidose vial. Cultures of abscesses from 20 of 23 case-patients grew Pseudomonas aeruginosa. Cultures of BC prepared at the clinic also grew P aeruginosa, suggesting that BC was the source of infection. Injection site cleaning with BC did not appear to be the route of infection since use of BC at the time of injection was not associated with abscess development. A more likely route of infection was injection of contaminated corticosteroid from multidose vials that could have been inoculated with pseudomonads via needle puncture after vial septa were wiped with contaminated BC. Benzalkonium chloride should not be used to clean injection vial septa or injection sites.

There is widespread support for the notion that subgroups of dyslexics can be identified who differ in their reading profiles: Developmental phonological dyslexia is characterized by poor nonword reading, while developmental surface dyslexia is distinguished by a particular difficulty in reading irregular words. However, there is much less agreement about how these subtypes, and particularly the surface dyslexic pattern, are to be accounted for within theoretical models of the reading system. To assist in addressing this issue, the heritability of reading deficits in dyslexic subtypes was examined using a twin sample. Subjects' scores on (a) an exception word reading task and (b) a nonword reading task were used to create a subtype dimension, and surface and phonological dyslexic subgroups were selected from the ends of this distribution. Reading deficits were found to be significantly heritable in both subgroups. However, the genetic contribution to the group reading deficit was much greater in the phonological dyslexics than in the surface dyslexics. The finding of differential genetic etiology across subtypes suggests that there is at least partial independence in the development of the cognitive processes involved in reading exception words and nonwords. Also, the results support accounts of surface dyslexia which emphasize a strong environmental contribution., (Copyright 1999 Academic Press.)

Reading disability (RD), or dyslexia, is a complex cognitive disorder manifested by difficulties in learning to read, in otherwise normal individuals. Individuals with RD manifest deficits in several reading and language skills. Previous research has suggested the existence of a quantitative-trait locus (QTL) for RD on the short arm of chromosome 6. In the present study, RD subjects' performance in several measures of word recognition and component skills of orthographic coding, phonological decoding, and phoneme awareness were individually subjected to QTL analysis, with a new sample of 126 sib pairs, by means of a multipoint mapping method and eight informative DNA markers on chromosome 6 (D6S461, D6S276, D6S105, D6S306, D6S258, D6S439, D6S291, and D6S1019). The results indicate significant linkage across a distance of at least 5 cM for deficits in orthographic (LOD = 3.10) and phonological (LOD = 2.42) skills, confirming previous findings.

In recent years behavioral genetic studies have provided conclusive evidence that reading disability and related learning disorders, such as mathematics disability, are due at least in part to heritable factors (DeFries et al. 1987; Alarcón et al. 1997). Although the observed relationship between performance in these areas also may be due substantially to genetic influences (Light and DeFries 1995; Thompson et al. 1991), relatively few studies have examined the genetic and environmental etiology of this covariation in a multivariate framework. In the present study data from 196 identical (monozygotic; MZ) and 155 same-sex fraternal (dizygotic; DZ) twin pairs in which at least one member of each pair evidenced reading problems in school (reading disabled) were subjected to a multivariate behavioral genetic analysis. Structural equation models were fitted to twin data for verbal IQ (VIQ), phonological decoding ability (PHON), reading performance (READ), and mathematics performance (MATH) to assess the extent to which VIQ and PHON mediate the observed covariation between READ and MATH. Results suggest that VIQ and PHON account for most of the covariation between READ and MATH. Moreover, approximately 82% of the observed correlation between READ and MATH was due to genetic factors that also influence VIQ and PHON. When data from 132 MZ and 91 same-sex DZ control twin pairs in which neither twin had a history of reading problems were subjected to the same analyses, the covariation between READ and MATH was found to be due to both genetic and shared environmental influences. Thus genetic factors that influence VIQ and PHON also contribute to the observed covariation between READ and MATH in both a reading-disabled and a control twin sample.

Eye fixation patterns of 21 dyslexic and 21 younger, nondyslexic readers were compared when they read aloud 2 texts. The study examined whether word-frequency and word-length effects previously found for skilled adult readers would generalize equally to younger dyslexic and nondyslexic readers. Significantly longer gaze durations and reinspection times were found for low-frequency and long words than for high-frequency and short words. The effects also showed up in the number of fixations on the target words. The effects did not differ significantly for the 2 experimental groups. The results run counter to the oculomotor dysfunction hypothesis of dyslexia. Instead, they support the view that both dyslexic and nondyslexic readers' eye fixation patterns reflect their difficulties in successfully identifying words in a text.

This article reports a study of the mentoring relationships that developed during predoctoral fellowships awarded to five nursing students who worked with faculty mentors at the University of Kansas, School of Nursing. Data were gathered through interviews and a written questionnaire from each of eight study participants (four of the five pairs). The analysis of interview and questionnaire data supported the existence of a mentoring relationship according to Yoder's (1990) model of mentoring, with the addition of two variables, socialization as a researcher and mutual sharing, that are unique to doctoral education. Themes that represented the experience of the mentor-protégé pairs were identified: (1) productivity, (2) work organization, (3) mutual learning, (4) problems encountered, (5) beneficial research application skills, and (6) innovative communication. All participants were enthusiastic about the experience, and students indicated increased confidence in application of the research process.

Reading with Orthographic and Segmented Speech (ROSS) programs use talking computers to deal with deficits in word recognition and phonological awareness. With ROSS, children read stories on a computer screen. Whenever they encounter a word they find difficult, they can request assistance by targeting the word with a mouse. The program highlights the word in segments and then pronounces the segments in order. In previous studies, children improved in reading, but children with relatively lower initial phonological awareness (PA) gained less than the others. In order to maximize the benefits from ROSS for all children, the current study aimed to improve PA before and while reading with ROSS, by using some programs based on theAuditory Discrimination in Depth method (Lindamood and Lindamood 1975), and others focusing on phoneme manipulation with speech feedback for all responses. The study compared the effects of this training with training in Comprehension Strategies (CS) based on Reciprocal Teaching techniques (Palincsar and Brown 1984), among second- to fifth-grade students with problems in word recognition. While both groups received equal instructional time in small-groups and with the computer, the groups differed in how much time they spent reading words in context. Whereas PA children spent half their computer time on PA exercises involving individual words and half reading words in context with ROSS, the CS group spent all their computer time reading words in context with ROSS. Both groups made significant gains in decoding, word recognition, and comprehension; however the PA groups gained significantly more than the CS group on all untimed tests of phoneme awareness, word recognition, and nonsense word reading. The CS children performed better on a test of time-limited word recognition; they also achieved higher comprehension scores, although only while reading with a trainer. The PA children's improved decoding skill led to greater accuracy, but slower responses with difficult words, after one semester's training.

Recent research has raised the question of whether age- and IQ-discrepancy forms of reading disability (RD) are distinguishable in terms of either their underlying linguistic deficit or their response to treatment, thus threatening the external validity of the traditional distinction between specific reading retardation and reading backwardness. The present study pursued the external validity of this distinction in three domains: (a) genetic etiology, (b) sex ratio and clinical correlates, and (c) neuropsychological profiles. Each of these domains was explored in the RD (n = 640) and control (n = 436) twins participating in the Colorado Reading Project (514 males, 562 females, with an overall mean age of 12.42 years). Little evidence for external validity was found in terms of the clinical correlates of attention deficit-hyperactivity disorder (ADHD), immune disorders, or handedness. Most importantly, there was no evidence of differential genetic etiology of the two phenotypes in this sample, in that deficits in both phenotypes were similarly heritable (h2g = .40 and .46 for age and IQ phenotypes, respectively) and the genetic correlation between them was high (rG = .88 to .96). However, the genetic and neuropsychological profile analyses did suggest that age- and IQ-discrepancy definitions of RD may relate differentially to component reading processes, such as phonological awareness and orthographic coding.

Previous studies suggest that adults and children divide spoken syllables into subsyllabic onset-rime units more readily than into any other kind of subsyllabic unit. We asked whether this same onset-rime segmentation might also be beneficial in teaching children to read. That is, can children learn more words segmented at the onset-rime boundary (e.g., CL-AP, D-ISH) than words segmented after the vowel (CLA-P, DI-SH)? In three experiments, first-grade students studied single words presented by a computer connected to a high-quality speech synthesizer. Experiment 1 used words of four letters but only three phonemes apiece (e.g., WHIP, DISH). In some of these words the onset-rime segmentation corresponded to the initial bigram (e.g., WH-IP); in some it did not (e.g., D-ISH). Experiments 2 and 3 used words of four letters and four phonemes (e.g., CLAP, CORN). In all three experiments, onset-rime segmentation proved more helpful than postvowel segmentation in short-term learning of the words.