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Pugh KR, Mencl WE, Jenner AR, Katz L, Frost SJ, Lee JR, Shaywitz SE, Shaywitz BA. Neurobiological studies of reading and reading disability. J Commun Disord 2001; 34:479-492. [PMID: 11725860 DOI: 10.1016/s0021-9924(01)00060-0] [Citation(s) in RCA: 302] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
UNLABELLED Evidence from neuroimaging studies, including our own, suggest that skilled word identification in reading is related to the functional integrity of two consolidated left hemisphere (LH) posterior systems: a dorsal (temporo-parietal) circuit and a ventral (occipito-temporal) circuit. This posterior system appears to be functionally disrupted in developmental dyslexia. Relative to nonimpaired readers, reading-disabled individuals demonstrate heightened reliance on both inferior frontal and right hemisphere posterior regions, presumably in compensation for the LH posterior difficulties. We propose a neurobiological account suggesting that for normally developing readers, the dorsal circuit predominates at first, and in conjunction with premotor systems, is associated with analytic processing necessary for learning to integrate orthographic with phonological and lexical semantic features of printed words. The ventral circuit constitutes a fast, late-developing, word form system, which underlies fluency in word recognition. LEARNING OUTCOMES As a result of this activity, (1) the participant will learn about a model of lexical processing involving specific cortical regions. (2) The participant will learn about evidence which supports the theory that two dorsal LH systems may be disrupted in developmental dyslexia. (3) The participant will learn that individuals with reading impairment may rely on other regions of the brain to compensate for the disruption of posterior function.
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Affiliation(s)
- K R Pugh
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510-8064, USA.
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Stein MT, Zentall S, Shaywitz SE, Shaywitz BA. A school-aged child with delayed reading skills. J Dev Behav Pediatr 2001; 22:S111-5. [PMID: 11332789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- M T Stein
- University of California, San Diego, USA
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Shaywitz BA, Shaywitz SE, Pugh KR, Fulbright RK, Skudlarski P, Mencl WE, Constable RT, Marchione KE, Fletcher JM, Klorman R, Lacadie C, Gore JC. The functional neural architecture of components of attention in language-processing tasks. Neuroimage 2001; 13:601-12. [PMID: 11305889 DOI: 10.1006/nimg.2000.0726] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Using functional magnetic resonance imaging we examined three important dimensions of attentional control (selective attention, divided attention, and executive function) in 25 neurologically normal, right-handed men and women, using tasks involving the perception and processing of printed words, spoken words, or both. In the context of language-processing manipulations: selective attention resulted in increased activation at left hemisphere parietal sites as well as at inferior frontal sites, divided attention resulted in additional increases in activation at these same left hemisphere sites and was also uniquely associated with increased activation of homologous sites in the right hemisphere, and executive function (measured during a complex task requiring sequential decision-making) resulted in increased activation at frontal sites relative to all other conditions. Our findings provide support for the belief that specific functional aspects of attentional control in language processing involve widely distributed but distinctive cortical systems, with mechanisms associated with the control of perceptual selectivity involving primarily parietal and inferior frontal sites and executive function engaging specific sites in frontal cortex.
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Affiliation(s)
- B A Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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Pugh KR, Mencl WE, Jenner AR, Katz L, Frost SJ, Lee JR, Shaywitz SE, Shaywitz BA. Functional neuroimaging studies of reading and reading disability (developmental dyslexia). Ment Retard Dev Disabil Res Rev 2000; 6:207-13. [PMID: 10982498 DOI: 10.1002/1098-2779(2000)6:3<207::aid-mrdd8>3.0.co;2-p] [Citation(s) in RCA: 417] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Converging evidence from a number of neuroimaging studies, including our own, suggest that fluent word identification in reading is related to the functional integrity of two consolidated left hemisphere (LH) posterior systems: a dorsal (temporo-parietal) circuit and a ventral (occipito-temporal) circuit. This posterior system is functionally disrupted in developmental dyslexia. Reading disabled readers, relative to nonimpaired readers, demonstrate heightened reliance on both inferior frontal and right hemisphere posterior regions, presumably in compensation for the LH posterior difficulties. We propose a neurobiological account suggesting that for normally developing readers the dorsal circuit predominates at first, and is associated with analytic processing necessary for learning to integrate orthographic features with phonological and lexical-semantic features of printed words. The ventral circuit constitutes a fast, late-developing, word identification system which underlies fluent word recognition in skilled readers.
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Affiliation(s)
- K R Pugh
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
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5
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Mencl WE, Pugh KR, Shaywitz SE, Shaywitz BA, Fulbright RK, Constable RT, Skudlarski P, Katz L, Marchione KE, Lacadie C, Gore JC. Network analysis of brain activations in working memory: behavior and age relationships. Microsc Res Tech 2000; 51:64-74. [PMID: 11002354 DOI: 10.1002/1097-0029(20001001)51:1<64::aid-jemt7>3.0.co;2-d] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Forty-six middle-aged female subjects were scanned using functional Magnetic Resonance Imaging (fMRI) during performance of three distinct stages of a working memory task-encoding, rehearsal, and recognition-for both printed pseudowords and visual forms. An expanse of areas, involving the inferior frontal, parietal, and extrastriate cortex, was active in response to stimuli during both the encoding and recognition periods. Additional increases during memory recognition were seen in right prefrontal regions, replicating a now-common finding [for reviews, see Fletcher et al. (1997) Trends Neurosci 20:213-218; MacLeod et al. (1998) NeuroImage 7:41-48], and broadly supporting the Hemispheric Encoding/Retrieval Asymmetry hypothesis [Tulving et al. (1994) Proc Natl Acad Sci USA 91:2016-2020]. Notably, this asymmetry was not qualified by the type of material being processed. A few sites demonstrated higher activity levels during the rehearsal period, in the absence of any new stimuli, including the medial extrastriate, precuneus, and the medial temporal lobe. Further analyses examined relationships among subjects' brain activations, age, and behavioral scores on working memory tests, acquired outside the scanner. Correlations between brain scores and behavior scores indicated that activations in a number of areas, mainly frontal, were associated with performance. A multivariate analysis, Partial Least Squares [McIntosh et al. (1996) NeuroImage 3:143-157, (1997) Hum Brain Map 5:323-327], was then used to extract component effects from this large set of univariate correlations. Results indicated that better memory performance outside the scanner was associated with higher activity at specific sites within the frontal and, additionally, the medial temporal lobes. Analysis of age effects revealed that younger subjects tended to activate more than older subjects in areas of extrastriate cortex, medial frontal cortex, and the right medial temporal lobe; older subjects tended to activate more than younger subjects in the insular cortex, right inferior temporal lobe, and right inferior frontal gyrus. These results extend recent reports indicating that these regions are specifically involved in the memory impairments seen with aging.
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Affiliation(s)
- W E Mencl
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06511, USA.
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Anderson GM, Dover MA, Yang BP, Holahan JM, Shaywitz SE, Marchione KE, Hall LM, Fletcher JM, Shaywitz BA. Adrenomedullary function during cognitive testing in attention-deficit/hyperactivity disorder. J Am Acad Child Adolesc Psychiatry 2000; 39:635-43. [PMID: 10802982 DOI: 10.1097/00004583-200005000-00018] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Reported correlations between epinephrine (EPI) excretion and classroom performance, the cognition-enhancing effects of EPI infusion, increased EPI excretion with stimulants, and reports of decreased EPI excretion in attention-deficit/hyperactivity disorder (ADHD) suggest that sympathoadrenomedullary function might be altered in ADHD. This hypothesis was tested by examining sympathetic and adrenomedullary functioning during cognitive testing in boys with diagnosed ADHD. METHOD Urinary excretion of EPI and norepinephrine during a 3-hour cognitive test battery was assessed in 7- to 13-year-old boys. Excretion rates (nanograms per hour per square meter of body surface area) were determined in 200 individuals with ADHD (diagnosed according to DSM-IV criteria), with or without co-occurring oppositional defiant/conduct disorder or learning disorder. A non-ADHD contrast group (n = 51) with similar comorbidity was also studied. RESULTS Substantially lower (mean +/- SE) urinary EPI excretion was observed in the ADHD-inattentive subtype (n = 71) compared with the control group (200 +/- 22 versus 278 +/- 24 ng/hr/m2; F = 5.99, p = .015, critical alpha = .017). No diagnostic group differences were seen for norepinephrine excretion. Correlational analysis of both parent- and teacher-rated behaviors revealed that inattention factors consistently negatively predicted urinary EPI excretion. CONCLUSIONS The data extend findings of lower adrenomedullary activity during cognitive challenge in individuals with ADHD and suggest that the alteration is associated with inattentive behavior.
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Affiliation(s)
- G M Anderson
- Child Study Center, Yale University School of Medicine, New Haven, CT 06510, USA.
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Ni W, Constable RT, Mencl WE, Pugh KR, Fulbright RK, Shaywitz SE, Shaywitz BA, Gore JC, Shankweiler D. An event-related neuroimaging study distinguishing form and content in sentence processing. J Cogn Neurosci 2000; 12:120-33. [PMID: 10769310 DOI: 10.1162/08989290051137648] [Citation(s) in RCA: 239] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Two coordinated experiments using functional Magnetic Resonance Imaging (fMRI) investigated whether the brain represents language form (grammatical structure) separately from its meaning content (semantics). While in the scanner, 14 young, unimpaired adults listened to simple sentences that were either nonanomalous or contained a grammatical error (for example, *Trees can grew.), or a semantic anomaly (for example, *Trees can eat.). A same⁄different tone pitch judgment task provided a baseline that isolated brain activity associated with linguistic processing from background activity generated by attention to the task and analysis of the auditory input. Sites selectively activated by sentence processing were found in both hemispheres in inferior frontal, middle, and superior frontal, superior temporal, and temporo-parietal regions. Effects of syntactic and semantic anomalies were differentiated by some nonoverlapping areas of activation: Syntactic anomaly triggered significantly increased activity in and around Broca's area, whereas semantic anomaly activated several other sites anteriorly and posteriorly, among them Wernicke's area. These dissociations occurred when listeners were not required to attend to the anomaly. The results confirm that linguistic operations in sentence processing can be isolated from nonlinguistic operations and support the hypothesis of a specialization for syntactic processing.
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Affiliation(s)
- W Ni
- Haskins Laboratories, 270 Crown St, New Haven, CT 06510.
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Pugh KR, Mencl WE, Shaywitz BA, Shaywitz SE, Fulbright RK, Constable RT, Skudlarski P, Marchione KE, Jenner AR, Fletcher JM, Liberman AM, Shankweiler DP, Katz L, Lacadie C, Gore JC. The angular gyrus in developmental dyslexia: task-specific differences in functional connectivity within posterior cortex. Psychol Sci 2000; 11:51-6. [PMID: 11228843 DOI: 10.1111/1467-9280.00214] [Citation(s) in RCA: 211] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Converging evidence from neuroimaging studies of developmental dyslexia reveals dysfunction at posterior brain regions centered in and around the angular gyrus in the left hemisphere. We examined functional connectivity (covariance) between the angular gyrus and related occipital and temporal lobe sites, across a series of print tasks that systematically varied demands on phonological assembly. Results indicate that for dyslexic readers a disruption in functional connectivity in the language-dominant left hemisphere is confined to those tasks that make explicit demands on assembly. In contrast, on print tasks that do not require phonological assembly, functional connectivity is strong for both dyslexic and nonimpaired readers. The findings support the view that neurobiological anomalies in developmental dyslexia are largely confined to the phonological-processing domain. In addition, the findings suggest that right-hemisphere posterior regions serve a compensatory role in mediating phonological performance in dyslexic readers.
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Affiliation(s)
- K R Pugh
- Department of Pediatrics, Yale University School of Medicine, P.O. Box 3333, New Haven, CT 06510-8064, USA
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Shaywitz SE, Fletcher JM, Holahan JM, Shneider AE, Marchione KE, Stuebing KK, Francis DJ, Pugh KR, Shaywitz BA. Persistence of dyslexia: the Connecticut Longitudinal Study at adolescence. Pediatrics 1999; 104:1351-9. [PMID: 10585988 DOI: 10.1542/peds.104.6.1351] [Citation(s) in RCA: 210] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE The outcome in adolescence of children diagnosed as dyslexic during the early years of school was examined in children prospectively identified in childhood and continuously followed to young adulthood. This sample offers a unique opportunity to investigate a prospectively identified sample of adolescents for whom there is no question of the childhood diagnosis and in whom highly analytic measures of reading and language can be administered in adolescence. DESIGN Children were recruited from the Connecticut Longitudinal Study, a cohort of 445 children representative of those children entering public kindergarten in Connecticut in 1983. Two groups were selected when the children were in grade 9: children who met criteria for persistent reading disability in grades 2 through 6 (persistently poor readers [PPR]; n = 21) and a comparison group of nondisabled children, subdivided into average readers (n = 35) and superior readers (n = 39). In grade 9, each child received a comprehensive assessment of academic, language, and other cognitive skills. RESULTS Measures of phonological awareness (but not orthographic awareness) were most significant in differentiating the 3 reading groups, with smaller contributions from measures of word finding and digit-span. Academic measures that best separated good from poor readers were decoding and spelling, whereas measures of math and reading comprehension did not. Measures of phonological awareness, followed next by teacher rating of academic skills were the best predictors of decoding, reading rate, and reading accuracy. In contrast, the best predictor of reading comprehension was word finding, with digit span and socioeconomic status also contributing significantly. Using a growth curve model (quadratic model of growth to a plateau) all 3 groups demonstrated similar patterns of growth over time, with the superior group outperforming the average group, and the average group outperforming the PPR group. There was no evidence that the children in the PPR group catch up in their reading skills. CONCLUSIONS Deficits in phonological coding continue to characterize dyslexic readers even in adolescence; performance on phonological processing measures contributes most to discriminating dyslexic and average readers, and average and superior readers as well. These data support and extend the findings of previous investigators indicating the continuing contribution of phonological processing to decoding words, reading rate, and accuracy and spelling. Children with dyslexia neither spontaneously remit nor do they demonstrate a lag mechanism for catching up in the development of reading skills. In adolescents, the rate of reading as well as facility with spelling may be most useful clinically in differentiating average from poor readers.
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Affiliation(s)
- S E Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510-8064, USA.
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Fulbright RK, Jenner AR, Mencl WE, Pugh KR, Shaywitz BA, Shaywitz SE, Frost SJ, Skudlarski P, Constable RT, Lacadie CM, Marchione KE, Gore JC. The cerebellum's role in reading: a functional MR imaging study. AJNR Am J Neuroradiol 1999; 20:1925-30. [PMID: 10588120 PMCID: PMC7657770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
BACKGROUND AND PURPOSE Long considered to have a role limited largely to motor-related functions, the cerebellum has recently been implicated as being involved in both perceptual and cognitive processes. Our purpose was to determine whether cerebellar activation occurs during cognitive tasks that differentially engage the component processes of word identification in reading. METHODS Forty-two neurologically normal adults underwent functional MR imaging of the cerebellum with a gradient-echo echo-planar technique while performing tasks designed to study the cognitive processing used in reading. A standard levels-of-processing paradigm was used. Participants were asked to determine whether pairs of words were written in the same case (orthographic processing), whether pairs of words and non-words rhymed with each other, respectively (phonologic assembly), and whether pairs of words belonged to the same category (semantic processing). Composite maps were generated from a general linear model based on a randomization of statistical parametric maps. RESULTS During phonologic assembly, cerebellar activation was observed in the middle and posterior aspects of the posterior superior fissure and adjacent simple lobule and semilunar lobule bilaterally and in posterior aspects of the simple lobule, superior semilunar lobule, and inferior semilunar lobule bilaterally. Semantic processing, however, resulted in activation in the deep nuclear region on the right and in the inferior vermis, in addition to posterior areas active in phonologic assembly, including the simple, superior semilunar, and inferior semilunar lobules. CONCLUSION The cerebellum is engaged during reading and differentially activates in response to phonologic and semantic tasks. These results indicate that the cerebellum contributes to the cognitive processes integral to reading.
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Affiliation(s)
- R K Fulbright
- Department of Diagnostic Radiology, Yale University, New Haven, CT 06520, USA
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Abstract
During a health supervision visit, the father of a 7.5-year-old African American second-grader asked about his son's progress in reading. He was concerned when, at a recent teacher-parent conference to review Darren's progress, the teacher remarked that Darren was not keeping up with reading skills compared with others in his class. She said that he had difficulty sounding out some words correctly. In addition, he could not recall words he had read the day before. The teacher commented that Darren was a gregarious, friendly child with better-than-average verbal communication skills. His achievement at math was age-appropriate; spelling, however, was difficult for Darren, with many deleted letters and reversals of written letters. A focused history did not reveal any risk factors for a learning problem in the prenatal or perinatal periods. Early motor, language, and social milestones were achieved on time. Darren had not experienced any head injury, loss of consciousness, or chronic medical illness. He had several friends, and his father denied any behavioral problems at home or at school. His teacher completed a DSM-IV-specific behavioral survey for attention-deficit/hyperactivity disorder (ADHD). It did not show any evidence of ADHD. Darren's father completed 1 year of college and is currently the manager of a neighborhood convenience store. His mother had a high school education; she recalled that she found it difficult to complete assignments that required reading or writing. She is employed as a waitress. Darren does not have any siblings. The pediatrician performed a complete physical examination, the results of which were normal, including visual acuity, audiometry, and a neurological examination. It was noted that Darren seemed to pause several times in response to questions or commands. On two occasions, during finger-nose testing and a request to assess tandem gait, directions required repetition. Overall, he was pleasant and seemed to enjoy the visit. His pediatrician concluded that he had a learning problem but she was uncertain about the next step. She asked herself, "Is there anything else I can do in the office to evaluate Darren's problem with learning? Should I quickly refer him for educational testing or encourage a reading tutor? What questions can I ask his teacher that would be helpful? Am I missing a medical disorder?"
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Affiliation(s)
- M T Stein
- University of California, San Diego, USA
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Abstract
Children with learning and attention disorders commonly present with symptoms of both types of disorders. In many children, this co-occurrence represents comorbid disorders that are separate but overlapping. Because of comorbidity, the presence of one disorder signals the need to evaluate for the other disorders. Evaluation and treatment approaches must address both disorders when present.
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Affiliation(s)
- J M Fletcher
- Department of Pediatrics, University of Texas-Houston Medical School, USA
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Klorman R, Hazel-Fernandez LA, Shaywitz SE, Fletcher JM, Marchione KE, Holahan JM, Stuebing KK, Shaywitz BA. Executive functioning deficits in attention-deficit/hyperactivity disorder are independent of oppositional defiant or reading disorder. J Am Acad Child Adolesc Psychiatry 1999; 38:1148-55. [PMID: 10504814 DOI: 10.1097/00004583-199909000-00020] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate deficits of executive functions in children with attention-deficit/hyperactivity disorder (ADHD) classified by type (combined [CT] or predominantly inattentive [IT]) and comorbidity with oppositional defiant disorder (ODD) and reading disorder (RD). METHOD The Wisconsin Card Sorting Test (WCST) and Tower of Hanoi (TOH) were administered to 28 community volunteers and 359 children (7.5-13.5 years old) divided into ADHD types, RD, and ODD. RESULTS ADHD/CT children solved fewer puzzles and violated more rules on the TOH than ADHD/IT or non-ADHD subjects. On the WCST there were no differences between diagnostic samples in perseverativeness, but ADHD/CT patients made more nonperseverative errors than ADHD/IT children. ODD was associated with moderately better TOH performance and RD with excessive rule breaks. CONCLUSIONS Executive functioning deficits were found for only ADHD/CT children and were independent of comorbidity with RD or ODD.
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Affiliation(s)
- R Klorman
- Department of Clinical and Social Sciences in Psychology, University of Rochester, New York 14620-0266, USA.
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Chang HT, Klorman R, Shaywitz SE, Fletcher JM, Marchione KE, Holahan JM, Stuebing KK, Brumaghim JT, Shaywitz BA. Paired-associate learning in attention-deficit/hyperactivity disorder as a function of hyperactivity-impulsivity and oppositional defiant disorder. J Abnorm Child Psychol 1999; 27:237-45. [PMID: 10438189 DOI: 10.1023/a:1021956507983] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A paired-associate learning (PAL) test was administered to 22 community volunteers without disruptive disorders and 197 children (7.5-13.5 years-old) presenting with the inattentive and combined subtypes of attention-deficit/hyperactivity disorder (ADHD) either in combination with or without oppositional defiant disorder (ODD). Participants were screened for learning disorders. In comparison to non-ADHD participants, children with ADHD achieved worse PAL and made errors rated as more acoustically and less semantically similar to the correct paired associates. These deficits were not related to hyperactivity-impulsivity or comorbid ODD. These results suggest that ADHD children are less competent at PAL and use less efficient learning strategies than their non-ADHD peers.
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Affiliation(s)
- H T Chang
- University of Rochester, New York 14627-0266, USA
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Shaywitz SE, Shaywitz BA, Pugh KR, Fulbright RK, Skudlarski P, Mencl WE, Constable RT, Naftolin F, Palter SF, Marchione KE, Katz L, Shankweiler DP, Fletcher JM, Lacadie C, Keltz M, Gore JC. Effect of estrogen on brain activation patterns in postmenopausal women during working memory tasks. JAMA 1999; 281:1197-202. [PMID: 10199429 DOI: 10.1001/jama.281.13.1197] [Citation(s) in RCA: 322] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT Preclinical studies suggest that estrogen affects neural structure and function in mature animals; clinical studies are less conclusive with many, but not all, studies showing a positive influence of estrogen on verbal memory in postmenopausal women. OBJECTIVE To investigate the effects of estrogen on brain activation patterns in postmenopausal women as they performed verbal and nonverbal working memory tasks. DESIGN Randomized, double-blind, placebo-controlled, crossover trial from 1996 through 1998. SETTING Community volunteers tested in a hospital setting. PATIENTS Forty-six postmenopausal women aged 33 to 61 years (mean [SD] age, 50.8 [4.7] years). INTERVENTION Twenty-one-day treatment with conjugated equine estrogens, 1.25 mg/d, randomly crossed over with identical placebo and a 14-day washout between treatments. MAIN OUTCOME MEASURES Brain activation patterns measured using functional magnetic resonance imaging during tasks involving verbal and nonverbal working memory. RESULTS Treatment with estrogen increased activation in the inferior parietal lobule during storage of verbal material and decreased activation in the inferior parietal lobule during storage of nonverbal material. Estrogen also increased activation in the right superior frontal gyrus during retrieval tasks, accompanied by greater left-hemisphere activation during encoding. The latter pattern represents a sharpening of the hemisphere encoding/retrieval asymmetry (HERA) effect. Estrogen did not affect actual performance of the verbal and nonverbal memory tasks. CONCLUSIONS Estrogen in a therapeutic dosage alters brain activation patterns in postmenopausal women in specific brain regions during the performance of the sorts of memory function that are called upon frequently during any given day. These results suggest that estrogen affects brain organization for memory in postmenopausal women.
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Affiliation(s)
- S E Shaywitz
- Department of Pediatrics, School of Medicine, Yale University, New Haven, Conn 06510-8064, USA.
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Constable RT, Skudlarski P, Mencl E, Pugh KR, Fulbright RK, Lacadie C, Shaywitz SE, Shaywitz BA. Quantifying and comparing region-of-interest activation patterns in functional brain MR imaging: methodology considerations. Magn Reson Imaging 1998; 16:289-300. [PMID: 9621970 DOI: 10.1016/s0730-725x(97)00278-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The general aims of functional brain magnetic resonance imaging (fMRI) studies are to ascertain which areas of the brain are activated during a specific task, the extent of this activation, whether different groups of subjects demonstrate different patterns of activation, and how these groups behave in different tasks. Many steps are involved in answering such questions and if each step is not carefully controlled the results may be influenced. This work has three objectives. Firstly, to present a technique for quantitatively evaluating methods used in functional imaging data analysis. While receiver-operator-characteristic (ROC) analysis has been used effectively to evaluate the ability of post-processing algorithms to detect true activations while rejecting false activations, it is difficult to adapt such a technique for comparisons of methods for quantitating activations. We present a technique based on the ANOVA, between two or more regions of interest (ROIs), subject groups, or activation tasks, over a range of statistical thresholds, which reveals the sensitivity of different activation quantification metrics to noise and other variables. Secondly, we use this technique to compare two methods of quantifying localized brain activation. There are numerous ways of quantifying the amount of activation present in a specific region of the brain in an individual subject. We compare the pixel count approach, which simply counts the number of pixels above an arbitrary statistical threshold, with an approach based on the sum of t-values above the same arbitrary t-value threshold. Finally, we examine the sensitivity of the results from an analysis of variance, to user defined parameters such as threshold and region of interest size. Both simulated and real functional magnetic resonance data are used to demonstrate these techniques.
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Affiliation(s)
- R T Constable
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT 06520-8042, USA.
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Shaywitz SE, Shaywitz BA, Pugh KR, Fulbright RK, Constable RT, Mencl WE, Shankweiler DP, Liberman AM, Skudlarski P, Fletcher JM, Katz L, Marchione KE, Lacadie C, Gatenby C, Gore JC. Functional disruption in the organization of the brain for reading in dyslexia. Proc Natl Acad Sci U S A 1998; 95:2636-41. [PMID: 9482939 PMCID: PMC19444 DOI: 10.1073/pnas.95.5.2636] [Citation(s) in RCA: 583] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Learning to read requires an awareness that spoken words can be decomposed into the phonologic constituents that the alphabetic characters represent. Such phonologic awareness is characteristically lacking in dyslexic readers who, therefore, have difficulty mapping the alphabetic characters onto the spoken word. To find the location and extent of the functional disruption in neural systems that underlies this impairment, we used functional magnetic resonance imaging to compare brain activation patterns in dyslexic and nonimpaired subjects as they performed tasks that made progressively greater demands on phonologic analysis. Brain activation patterns differed significantly between the groups with dyslexic readers showing relative underactivation in posterior regions (Wernicke's area, the angular gyrus, and striate cortex) and relative overactivation in an anterior region (inferior frontal gyrus). These results support a conclusion that the impairment in dyslexia is phonologic in nature and that these brain activation patterns may provide a neural signature for this impairment.
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Affiliation(s)
- S E Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA.
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Affiliation(s)
- S E Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510, USA
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Pugh KR, Shaywitz BA, Shaywitz SE, Shankweiler DP, Katz L, Fletcher JM, Skudlarski P, Fulbright RK, Constable RT, Bronen RA, Lacadie C, Gore JC. Predicting reading performance from neuroimaging profiles: the cerebral basis of phonological effects in printed word identification. J Exp Psychol Hum Percept Perform 1997. [PMID: 9103996 DOI: 10.1037//0096-1523.23.2.299] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study linked 2 experimental paradigms for the analytic study of reading that heretofore have been used separately. Measures on a lexical decision task designed to isolate phonological effects in the identification of printed words were examined in young adults. The results were related to previously obtained measures of brain activation patterns for these participants derived from functional magnetic resonance imaging (fMRI). The fMRI measures were taken as the participants performed tasks that were designed to isolate orthographic, phonological, and lexical-semantic processes in reading. Individual differences in the magnitude of phonological effects in word recognition, as indicated by spelling-to-sound regularity effects on lexical decision latencies and by sensitivity to stimulus length effects, were strongly related to differences in the degree of hemispheric lateralization in 2 cortical regions.
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Affiliation(s)
- K R Pugh
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510-8064, USA.
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Pugh KR, Shaywitz BA, Shaywitz SE, Shankweiler DP, Katz L, Fletcher JM, Skudlarski P, Fulbright RK, Constable RT, Bronen RA, Lacadie C, Gore JC. Predicting reading performance from neuroimaging profiles: the cerebral basis of phonological effects in printed word identification. J Exp Psychol Hum Percept Perform 1997; 23:299-318. [PMID: 9103996 DOI: 10.1037/0096-1523.23.2.299] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This study linked 2 experimental paradigms for the analytic study of reading that heretofore have been used separately. Measures on a lexical decision task designed to isolate phonological effects in the identification of printed words were examined in young adults. The results were related to previously obtained measures of brain activation patterns for these participants derived from functional magnetic resonance imaging (fMRI). The fMRI measures were taken as the participants performed tasks that were designed to isolate orthographic, phonological, and lexical-semantic processes in reading. Individual differences in the magnitude of phonological effects in word recognition, as indicated by spelling-to-sound regularity effects on lexical decision latencies and by sensitivity to stimulus length effects, were strongly related to differences in the degree of hemispheric lateralization in 2 cortical regions.
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Affiliation(s)
- K R Pugh
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510-8064, USA.
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Shaywitz BA, Fletcher JM, Shaywitz SE. Attention-deficit/hyperactivity disorder. Adv Pediatr 1997; 44:331-67. [PMID: 9265975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this chapter we have reviewed the diagnosis and management of attention deficit disorder, focusing particularly on the role of stimulant therapy in ADHD. Hisorical review suggests that ADHD has roots that extend back almost a century. The definition of ADHD is based on inclusion and exclusion criteria that are established by history and reflect behavioral concerns. Attention-deficit/hyperactivity disorder is a chronic disorder affecting the child's home, school, and community life. The primary symptoms of the disorder manifest a developmental pattern: activity diminishes while attentional deficits persist. Major sources of concern are the secondary and often more resistant problems of learning difficulties, behavioral problems, lack of peer acceptance, and low self-esteem. An often frustrating and perplexing characteristic of the disorder is its marked variability-over time, across situations, and within the same child and similar situations. Educational management represents an important priority and often forms the cornerstone of all other therapies, nonpharmacologic or pharmacologic. Cognitive-behavioral therapies represent the most widely used alternative to pharmacotherapy. Although the effects of CBT alone are disappointing, recent studies suggest that such therapies may provide a useful adjunct to pharmacotherapy and may be helpful when children are tapered off medication. Psychotherapy, or a combination of psychotherapy and medication (termed multimodality therapy), may also be useful. Pharmacotherapy for ADHD originated almost 60 years ago, and at this time the ameliorative effects of medications in ADHD are well established. The general skepticism of experienced clinicians, coupled with a climate where parents are reluctant to medicare children, serves to limit their use except where indicated. Although the effects of stimulants on attention and activity seem well established, effects on cognition, conduct, and social behavior are more controversial. Within recent years, a great deal has been learned about the pharmacokinetics of stimulants in children with ADHD, providing a rational basis for administration. It is also clear that side effects are minimal, the most serious being the possibility of the emergence of tics. Whereas stimulants are clearly the most effective agents, other agents, including antidepressants, may also be effective. Recent advances may now provide an opportunity to better understand the neural and molecular basis for ADHD. Recent advances in imaging technology, particularly fMRI, offer an opportunity to examine the neural basis of ADHD, and advances in genetics may provide clues to its etiology.
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Affiliation(s)
- B A Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
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Pugh KR, offywitz BA, Shaywitz SE, Fulbright RK, Byrd D, Skudlarski P, Shankweiler DP, Katz L, Constable RT, Fletcher J, Lacadie C, Marchione K, Gore JC. Auditory selective attention: an fMRI investigation. Neuroimage 1996; 4:159-73. [PMID: 9345506 DOI: 10.1006/nimg.1996.0067] [Citation(s) in RCA: 198] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In the present experiment, 25 adult subjects discriminated speech tokens ([ba]/[da]) or made pitch judgments on tone stimuli (rising/falling) under both binaural and dichotic listening conditions. We observed that when listeners performed tasks under the dichotic conditions, during which greater demands are made on auditory selective attention, activation within the posterior (parietal) attention system and at primary processing sites in the superior temporal and inferior frontal regions was increased. The cingulate gyrus within the anterior attention system was not influenced by this manipulation. Hemispheric differences between speech and nonspeech tasks were also observed, both at Broca's Area within the inferior frontal gyrus and in the middle temporal gyrus.
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Affiliation(s)
- K R Pugh
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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Affiliation(s)
- S E Shaywitz
- Yale Center for the Study of Learning and Attention, USA
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Pugh KR, Shaywitz BA, Shaywitz SE, Constable RT, Skudlarski P, Fulbright RK, Bronen RA, Shankweiler DP, Katz L, Fletcher JM, Gore JC. Cerebral organization of component processes in reading. Brain 1996; 119 ( Pt 4):1221-38. [PMID: 8813285 DOI: 10.1093/brain/119.4.1221] [Citation(s) in RCA: 414] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The cerebral organization of word identification processes in reading was examined using functional magnetic resonance imaging (fMRI). Changes in fMRI signal intensities were measured in 38 subjects (19 males and 19 females) during visual (line judgement), orthographic (letter case judgement), phonological (nonword rhyme judgement) and semantic (semantic category judgement) tasks. A strategy of multiple subtractions was employed in order to validate relationships between structure and function. Orthographic processing made maximum demands on extrastriate sites, phonological processing on a number of frontal and temporal sites, and lexical-semantic processing was most strongly associated with middle and superior temporal sites. Significant sex differences in the cerebral organization of reading-related processes were also observed.
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Affiliation(s)
- K R Pugh
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510-8064, USA
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Girardi NL, Shaywitz SE, Shaywitz BA, Marchione K, Fleischman SJ, Jones TW, Tamborlane WV. Blunted catecholamine responses after glucose ingestion in children with attention deficit disorder. Pediatr Res 1995; 38:539-42. [PMID: 8559606 DOI: 10.1203/00006450-199510000-00011] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Eating simple sugars has been suggested as having adverse behavioral and cognitive effects in children with attention deficit disorder (ADD), but a physiologic mechanism has not been established. To address this issue, metabolic, hormonal, and cognitive responses to a standard oral glucose load (1.75 g/kg) were compared in 17 children with ADD and 11 control children. Baseline and oral glucose-stimulated plasma glucose and insulin levels were similar in both groups, including the nadir glucose level 3-5 h after oral glucose (3.5 +/- 0.2 mmol/L in ADD and 3.3 +/- 0.2 mmol/L in control children). The late glucose fall stimulated a rise in plasma epinephrine that was nearly 50% lower in ADD than in control children (1212 +/- 202 pmol/L versus 2228 +/- 436 pmol/L, p < 0.02). Plasma norepinephrine levels were also lower in ADD than in control children, whereas growth hormone and glucagon concentrations did not differ between the groups. Matching test scores were lower and reaction times faster in ADD than in control children before and after oral glucose, and both groups showed a deterioration on the continuous performance test in association with the late fall in glucose and rise in epinephrine. These data suggest that children with ADD have a general impairment of sympathetic activation involving adrenomedullary as well as well as central catecholamine regulation.
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Affiliation(s)
- N L Girardi
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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Shaywitz BA, Shaywitz SE, Pugh KR, Constable RT, Skudlarski P, Fulbright RK, Bronen RA, Fletcher JM, Shankweiler DP, Katz L. Sex differences in the functional organization of the brain for language. Nature 1995; 373:607-9. [PMID: 7854416 DOI: 10.1038/373607a0] [Citation(s) in RCA: 741] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A much debated question is whether sex differences exist in the functional organization of the brain for language. A long-held hypothesis posits that language functions are more likely to be highly lateralized in males and to be represented in both cerebral hemispheres in females, but attempts to demonstrate this have been inconclusive. Here we use echo-planar functional magnetic resonance imaging to study 38 right-handed subjects (19 males and 19 females) during orthographic (letter recognition), phonological (rhyme) and semantic (semantic category) tasks. During phonological tasks, brain activation in males is lateralized to the left inferior frontal gyrus regions; in females the pattern of activation is very different, engaging more diffuse neural systems that involve both the left and right inferior frontal gyrus. Our data provide clear evidence for a sex difference in the functional organization of the brain for language and indicate that these variations exist at the level of phonological processing.
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Affiliation(s)
- B A Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510-8064
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Abstract
This paper provides an overview of current conceptualizations of learning disabilities and ADHD, a conceptual framework critical for defining and classifying each disorder and for distinguishing each disorder from the other and from other, less common problems of childhood. At a most basic level, reading disability or dyslexia (the most common and best defined of the learning disabilities) and ADHD represent two distinct disorders that may frequently cooccur in the same unfortunate child but that can be clearly distinguished from one another. Reading disability represents a disorder of cognitive functioning. In contrast, ADHD is defined by the child's behavior as perceived by the child's parents and teachers; ADHD thus refers to a disorder affecting primarily the behavioral domain. Within the last decade, considerable progress has been made in our understanding of reading and reading disability. Converging evidence from several lines of investigation now indicates that reading ability conforms to a normal distribution model, so that there is a continuum of reading ability and reading disability. Children along this continuum differ by degree but not in kind. Cutoff points may be instituted to segment this continuous distribution, but these will be arbitrary and will not reflect any natural joints in nature; there is no second mode or "hump" in the distribution of reading ability. The normal model of reading and reading disability indicates that reading disability is related to normal reading ability, that there is a seamless transition from good to poor reading ability. Awareness of this relationship is critical to our approach to understanding the basis of reading disability.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- B A Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520-8064, USA
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Schultz RT, Cho NK, Staib LH, Kier LE, Fletcher JM, Shaywitz SE, Shankweiler DP, Katz L, Gore JC, Duncan JS. Brain morphology in normal and dyslexic children: the influence of sex and age. Ann Neurol 1994; 35:732-42. [PMID: 8210231 DOI: 10.1002/ana.410350615] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Morphometric magnetic resonance imaging techniques were used to compare the convolutional surface area of the planum temporale, temporal lobe volume and superior surface area, and an estimate of overall brain volume in a homogeneous sample of 17 dyslexic children (7 girls) and 14 nonimpaired children (7 girls). Substantial sex differences were apparent for all measured regions, with all the measurements in boys being significantly larger. Age, even within the narrow range employed here (7.5-9.7 years), was positively correlated with the size of each brain region. While initial analyses suggested smaller left hemisphere structures in dyslexics compared to control subjects, subsequent analyses controlling for age and overall brain size revealed no significant differences between dyslexics and nonimpaired children on a variety of measures, in particular surface area and symmetry of the planum temporale. We suggest that differences in subject characteristics (i.e., sex, age, handedness, and definition of dyslexia) as well as procedural variations in the methods used to acquire images and to define and measure anatomical regions of interest such as the planum temporale all may play an important role in explaining apparent discrepant results in the neuroimaging literature on dyslexia.
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Affiliation(s)
- R T Schultz
- Child Study Centre, Yale University School of Medicine, New Haven, CT
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Shaywitz BA, Sullivan CM, Anderson GM, Gillespie SM, Sullivan B, Shaywitz SE. Aspartame, behavior, and cognitive function in children with attention deficit disorder. Pediatrics 1994; 93:70-5. [PMID: 7505423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
OBJECTIVE To determine the effects of large doses of aspartame on behavior, cognition, and monoamine metabolism in children with attention deficit disorder. DESIGN A randomized, double-blind, placebo-controlled crossover study of unmedicated children meeting Diagnostic and Statistical Manual of Mental Disorders (3rd ed) criteria for attention deficit disorder. SETTING Behavioral assessments were performed in the child's home by their parents and in the classroom by a teacher. Cognitive tests were administered and blood drawing was performed during a 2-day inpatient admission to our Children's Study Center. INTERVENTIONS Administration of aspartame (single morning dose, 34 mg/kg) or placebo for alternate 2-week periods. MAIN OUTCOME MEASURES Behavioral and cognitive tests included the Matching Familiar Figures Test (MFFT), Children's Checking Task (CCT), the Airplane Test, the Wisconsin Card Sorting Test (WCST), the Subjects Treatment Emergent Symptom Scale (STESS), the Multigrade Inventory for Teachers (MIT), and the Conners Behavior Rating Scale. Blood was drawn for complete blood cell count and liver function tests, as well as amino acid, methanol, formate, serotonin, and monoamine metabolite analyses, and urine was collected for measurement of catecholamine and monoamine metabolite excretion. RESULTS No clinically significant differences between aspartame and placebo were found for the STESS, MIT, or Conners ratings, or for the MFFT, CCT, WCST, or Airplane cognition tests. Also, no differences were noted for any of the biochemical measures, except for the expected increase in plasma phenylalanine and tyrosine following aspartame. CONCLUSIONS The findings indicate that aspartame at greater than 10 times usual consumption has no effect on the cognitive and behavioral status of children with attention deficit disorder. In addition, aspartame does not appear to affect urinary excretion rates of monoamines and metabolites.
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Affiliation(s)
- B A Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510
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Fletcher JM, Francis DJ, Rourke BP, Shaywitz SE, Shaywitz BA. The validity of discrepancy-based definitions of reading disabilities. J Learn Disabil 1992; 25:555-61, 573. [PMID: 1431539 DOI: 10.1177/002221949202500903] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
This study addressed the validity of distinguishing children with reading disabilities according to the presence or absence of discrepancies between intelligence test scores and academic achievement. Three definitions of reading disability were used to provide criteria for five groups of children who (a) met a discrepancy-based definition uncorrected for the correlation of IQ and achievement; (b) met a discrepancy-based definition correcting for the correlation of IQ and achievement; (c) met a low achievement definition with no IQ discrepancy; (d) met criteria a and b; and (e) met none of the criteria and had no reading disability. Comparison of these five groups on a set of 10 neuropsychological tests corrected for correlations with IQ showed that group differences were small and accounted for little of the variability among groups. These results question the validity of segregating children with reading deficiencies according to discrepancies with IQ scores.
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Affiliation(s)
- J M Fletcher
- Department of Pediatrics, University of Texas Medical School, Houston 77030
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Abstract
BACKGROUND Dyslexia is now widely believed to be a biologically based disorder that is distinct from other, less specific reading problems. According to this view, reading ability is considered to follow a bimodal distribution, with dyslexia as the lower mode. We hypothesized that, instead, reading ability follows a normal distribution, with dyslexia at the lower end of the continuum. METHODS AND RESULTS We used data from the Connecticut Longitudinal Study, a sample survey of 414 Connecticut children who entered kindergarten in 1983 and were followed as a longitudinal cohort. Dyslexia was defined in terms of a discrepancy score, which represents the difference between actual reading achievement and achievement predicted on the basis of measures of intelligence. Data were available from intelligence tests administered in grades 1, 3, and 5 and achievement tests administered yearly in grades 1 through 6. For each child there were 108 possible discrepancy scores ([3 x 3 years] x [2 x 6 years]) based on combinations of the ability scores (full-scale, verbal, and performance IQ) in each of three years and two achievement scores (reading and mathematics) in each of six years. We demonstrated that each of the discrepancy scores followed a univariate normal distribution and that the interrelation of two different discrepancy scores followed a bivariate normal distribution. At most, only 9 of 108 discrepancy scores (8.3 percent) and 171 of 3402 pairs of discrepancy scores (5.0 percent) were significantly different (at the 5 percent level) from the expected scores--well within the expected values for data with univariate and bivariate normal distributions, respectively. We also examined the stability of dyslexia over time. The normal-distribution model predicted (and the data indicated) that only 7 of the 25 children (28 percent) classified as having dyslexia in grade 1 would also be classified as having dyslexia in grade 3. CONCLUSIONS Reading difficulties, including dyslexia, occur as part of a continuum that also includes normal reading ability. Dyslexia is not an all-or-none phenomenon, but like hypertension, occurs in degrees. The variability inherent in the diagnosis of dyslexia can be both quantified and predicted with use of the normal-distribution model.
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Affiliation(s)
- S E Shaywitz
- Department of Pediatrics, Child Study Center, Yale University School of Medicine, New Haven, Conn
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Abstract
In this report, we examine the interrelationships between attention deficit disorder (ADD), learning disabilities (LD), and conduct and oppositional disorders (COD). We indicate that it is reasonable to consider ADD as a distinct entity, frequently co-occurring with LD on the one hand, and COD on the other. The first section reviews the interrelationships between ADD and LD. Here we focus on definitional issues, trace the historical antecedents of ADD and LD, examine the prevalence of ADD and LD, and review studies designed to differentiate cognitive from attentional mechanisms in children with ADD, LD, or both. In the next section, we review the evidence linking ADD with COD, a distinction blurred in earlier investigations by problems with referral bias. More recent studies suggest that the antecedents, clinical characteristics, and prognosis may differ in children with ADD alone compared to those with ADD in association with COD.
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Affiliation(s)
- B A Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510-8064
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Shaywitz SE, Shaywitz BA, Fletcher JM, Escobar MD. Prevalence of reading disability in boys and girls. Results of the Connecticut Longitudinal Study. JAMA 1990; 264:998-1002. [PMID: 2376893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We hypothesized that results of previous investigations indicating an increased prevalence of reading disability in boys compared with girls reflected a bias in subject selection. In an epidemiologic sample of 215 girls and 199 boys, we identified two groups of reading-disabled children: research identified and school identified. Results indicated no significant differences in the prevalence of reading disability in research-identified boys compared with research-identified girls in either second (17[8.7%] of 196 boys; 15[6.9%] of 216 girls) or third grade (18[9.0%] of 199 boys; 13[6.0%] of 215 girls). In contrast, school identification resulted in the classification of 27 (13.6%) of 198 boys and seven (3.2%) of 216 girls in second grade and 20 (10.0%) of 199 boys and nine (4.2%) of 215 girls in third grade. Our data indicate that school-identified samples are almost unavoidably subject to a referral bias and that reports of an increased prevalence of reading disability in boys may reflect this bias in ascertainment. These findings caution against relying solely on schools for identification of reading-disabled children.
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Affiliation(s)
- S E Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510-8064
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Shaywitz BA, Shaywitz SE, Sebrechts MM, Anderson GM, Cohen DJ, Jatlow P, Young JG. Growth hormone and prolactin response to methylphenidate in children with attention deficit disorder. Life Sci 1990; 46:625-33. [PMID: 2308471 DOI: 10.1016/0024-3205(90)90131-a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Utilizing a double-blind, drug-placebo design, we examined growth hormone (GH) and prolactin (Pro) response to oral administration of methylphenidate (MPH) in 14 boys (ages 7.0-12.4 years) with Attention Deficit Disorder (ADD). Four conditions representing three different MPH doses (0.3 mg/kg O.D., 0.3 mg/kg B.I.D., 0.6 mg/kg O.D.) and Placebo were compared in each subject, each condition lasting for a period of 3 weeks. GH and Pro response were measured both as maximum peak GH (DGH) or nadir of Pro (DPro) as well as area under the curve for the first four hours after MPH administration (AUCGH, AUCPro). Behavioral measures included parent ratings on the Yale Children's Inventory and teacher ratings on the Yale and Conners Behavior Rating Scales and Kagan's Matching Familiar Figures Test (MFFT). Prolactin response as measured by AUCPro was significantly increased after MPH compared to placebo (t = 2.04, p less than 0.05, placebo vs all doses MPH). This difference observed for AUCPro between placebo and MPH was evident as well when we considered the number of times AUCPro declined after MPH as compared to placebo (p = .018, Fisher's exact test). Within-subjects analysis of covariance demonstrated significant correlations between the improvement in reaction time on the MFFT and 1) GH response (AUCGH, r = .58, p less than .001) and 2) prolactin response (AUCPro, r = .40, p less than .05) and between improvement in attention as measured on the Yale BRS and GH response (AUCGH, r = .57, p less than .05). Our findings suggest that measures other than GH and prolactin may be more desirable measures of brain catecholaminergic functioning.
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Affiliation(s)
- B A Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510-8064
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Abstract
Our study examined the hypothesis that if epilepsy adversely influences the cognitive and behavioral performance of children, then children with both attention deficit-hyperactivity disorder and epilepsy (ADHD-Sz) should exhibit more severe cognitive and behavioral difficulties and be more likely to demonstrate abnormalities on cranial computed tomography than ADHD children without epilepsy. We compared ADHD-Sz and ADHD patients using a variety of psychologic, behavioral, and educational measures, as well as cranial computed tomography. ADHD-Sz children scored significantly below the ADHD group on the Wechsler Intelligence Scale for Children-Revised (performance and full scale scores). In both ADHD-Sz and ADHD groups, the prevalence of learning disabilities (LD) and a variety of behavioral features were similar. Neither seizure disorder nor ADHD was associated with an increased incidence of structural abnormalities or asymmetries of the brain. These findings support the belief that epilepsy adversely affects IQ but does not appear to affect the prevalence of LD or behavioral abnormalities in ADHD children. They further support the accumulating body of data demonstrating normal brain anatomy in ADHD by computed tomography.
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Affiliation(s)
- R O Kinney
- Department of Internal Medicine, Park Nicollet Medical Center, Brooklyn Center, Minnesota
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Shaywitz SE, Shaywitz BA. Increased medication use in attention-deficit hyperactivity disorder: regressive or appropriate? JAMA 1988; 260:2270-2. [PMID: 3050168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- S E Shaywitz
- Yale University School of Medicine, New Haven, Conn
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Shaywitz SE, Shaywitz BA, Schnell C, Towle VR. Concurrent and predictive validity of the Yale Children's Inventory: an instrument to assess children with attentional deficits and learning disabilities. Pediatrics 1988; 81:562-71. [PMID: 3353191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The Yale Children's Inventory rating scales for completion by parents were developed to improve the ability of clinicians and researchers to evaluate the school-related problems of children. The inventory consists of 11 narrow-band and two broad-band scales, the Behavioral and the Cognitive. The concurrent and predictive validity of the Yale Children's Inventory scales are reported in a school-based sample of 103 boys. External criterion variables were obtained from parents, teachers, and standardized tests administered to the children. We found that the Attention scale overlaps both broad-band domains, indicating the importance and the intrinsic relationship of attention to both behavioral and cognitive functions, which supports the Diagnostic and Statistical Manual of Mental Disorders, ed 3 nosology for disorders of attention and activity regulation. It also increases the number of children whose assessment may be enhanced by the availability of systematic parent report forms.
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Affiliation(s)
- S E Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510
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Abstract
This review focuses on selected issues in the rapidly proliferating scientific literature on attention deficit disorder (ADD). It encompasses a brief overview of ADD, including a review of the historical trends, causation, and a description of the clinical characteristics. Critical issues fundamental to understanding of ADD are addressed next. Evidence is presented to suggest that there are several groups of children with ADD who are currently under-identified and therefore, underserved (girls with ADD; ADD without hyperactivity). The concept is introduced of uncomplicated ADD and ADD-Plus (ADD-P), a term used to designate ADD associated with other complicating features such as conduct disorder. Specific methodologic issues and their relationship to the under-identification of these groups of children follows. This discussion encompasses the reasons for diagnostic imprecision and inconsistency, emphasizing the problem of selective referral patterns and how it results in an inaccurate portrait of ADD. We then present new approaches to the definition and diagnosis of ADD based on empiric studies designed to circumvent some of these problems. We conclude with a summary of the implications of these findings, and recommendations for public policy in ADD, particularly the need to recognize that ADD may occur even in the most intellectually gifted individuals and even in students in select colleges. Often these children with the highest potential are penalized most, not because of conceptual limitations or because they do not understand, but because educators often fail to recognize the symptom complex. Many of these children are succeeding through intelligence and great effort, but many more could succeed with proper identification.
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Affiliation(s)
- S E Shaywitz
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510
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Shaywitz SE, Schnell C, Shaywitz BA, Towle VR. Yale Children's Inventory (YCI): an instrument to assess children with attentional deficits and learning disabilities. I. Scale development and psychometric properties. J Abnorm Child Psychol 1986; 14:347-64. [PMID: 3760344 DOI: 10.1007/bf00915431] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The Yale Children's Inventory (YCI), a parent-based rating scale, and the scales derived from it have been developed to identify and measure multiple dimensions of learning disabilities with particular emphasis on attentional deficits. Scale construction was based on factor-analytic procedures. Measures of internal consistency, test-retest reliability, and coefficients of congruence support the reliability and stability of the 11 scales. A discriminant function classified normal and learning-disabled children with a relatively high rate of accuracy. The relationship and content of the three relevant YCI scales were compared to the DSM-III diagnostic categories for ADD. As operationalized, DSM-III criteria for hyperactivity formed a cohesive factor, while criteria for attention and impulsivity were not distinguishable from each other since they loaded together on a single factor. In contrast, the equivalent YCI scales for attention, impulsivity, and hyperactivity were found to be distinct.
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Riddle MA, Shaywitz BA, Leckman JF, Anderson GM, Shaywitz SE, Hardin MT, Ort SI, Cohen DJ. Brief debrisoquin administration to assess central dopaminergic function in children. Life Sci 1986; 38:1041-8. [PMID: 3456480 DOI: 10.1016/0024-3205(86)90239-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Central dopaminergic (DA) function in children was assessed by monitoring plasma-free homovanillic acid (pHVA) levels after brief (18 hour) administration with debrisoquin sulfate, a peripherally active antihypertensive agent that blocks peripheral, but not central, HVA production. Brief debrisoquin administration resulted in marked reductions in pHVA in each of six patients studied. In five of the six patients, post-debrisoquin pHVA levels remained relatively stable over the six-hour period of observation. No significant cardiovascular or behavioral side effects of debrisoquin were observed. The brief debrisoquin administration method appears to be a safe, simple, and potentially valid peripheral technique for evaluating aspects of central dopaminergic function in children with neuropsychiatric disorders. Additional work is needed to further establish this method's validity and reliability.
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Sebrechts MM, Shaywitz SE, Shaywitz BA, Jatlow P, Anderson GM, Cohen DJ. Components of attention, methylphenidate dosage, and blood levels in children with attention deficit disorder. Pediatrics 1986; 77:222-8. [PMID: 3945535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In this study we analyzed some of the cognitive components that may constitute attention deficit disorder. It consisted of a double-blind, drug-placebo study of 12 children being treated with three doses of methylphenidate and placebo. Results of an attentional test battery, teacher and parent ratings, and blood levels of methylphenidate are reported. In general, performance was best with 0.6 mg/kg of methylphenidate (the highest dose tested) and worst with placebo. It is argued that no single test provides a complete assessment of attentional deficits and that methylphenidate can improve performance by affecting the allocation of cognitive resources to a task.
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Berry CA, Shaywitz SE, Shaywitz BA. Girls with attention deficit disorder: a silent minority? A report on behavioral and cognitive characteristics. Pediatrics 1985; 76:801-9. [PMID: 4058990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A sample of girls and boys with attention deficit disorder (ADD) were examined for within-group sex differences and compared with control boys and girls on historical, behavioral, and cognitive characteristics. Profiles of essential and secondary features of ADD support the Diagnostic and Statistical Manual of Mental Disorders nosology for ADD with and without hyperactivity as clinically distinct subtypes of ADD, with the girls and boys with ADD with hyperactivity exhibiting attentional, behavioral, and cognitive impairments, and the children with ADD without hyperactivity exhibiting deficits along an attentional/cognitive axis. Management problems and antisocial behaviors were correlates of hyperactivity, and increased impulsivity was not associated with attentional deficits in the absence of hyperactivity. Within the ADD with hyperactivity group, the girls demonstrated more severe cognitive impairments, particularly in the area of language function, were younger at the time referral for medical attention, and tended to come from families of lower socioeconomic status. Disruptive, uncontrolled behaviors were more frequent among the boys with ADD with hyperactivity. The girls with ADD without hyperactivity demonstrated poorer self-esteem and were significantly older than the boys with ADD without hyperactivity at referral. Girls in both ADD with and without hyperactivity groups were more likely to suffer peer rejection than their male counterparts. The results of this study suggest that girls with ADD may be underidentified and that cognitive deficits have a more prominent role in the identification of girls, whereas behavioral disturbances increase the likelihood of identification for boys.
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Smith MO, Shaywitz SE, Shaywitz BA, Gertner JM, Raskin LA, Gelwan EM. Exogenous growth hormone levels predict attentional performance: a preliminary report. J Dev Behav Pediatr 1985; 6:273-8. [PMID: 3905862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The imminent commercial availability of synthetic growth hormone (GH) and the potential for large scale and possibly indiscriminant use mandate a critical examination of possible adverse effects. This double-blind study examined the effects of human GH on attention. Treatment of eight GH-deficient children, aged 8.7 to 14.1 years, was suspended to establish base lines. Injections with GH (0.1 units/kg) and placebo followed in counterbalanced 2-week periods. At the end of each period, GH levels were assayed, and attention was tested. Scores earned under the GH condition did not differ from base line and placebo values. However, patients displaying high levels (14 +/- 2.12 ng/ml) of exogenous GH 12 hours after injection generally surpassed norms and patients with low levels (3.5 +/- 1.12 ng/ml) of GH under all conditions of the experiment. If 12-hour levels in this study are indicative of the fate of GH received during therapy, prolonged use of GH may bring benefits to attention that vary directly with half-life.
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Shaywitz SE, Shaywitz BA. Attention deficit disorder. Pediatrics 1985; 76:623-5. [PMID: 4047808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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Rimar S, Shaywitz SE, Shaywitz BA, Lister G, Anderson GM, Leckman JF, Cohen DJ. Autonomic dysfunction, peripheral neuropathy, and depression. Pediatr Neurol 1985; 1:120-3. [PMID: 2854734 DOI: 10.1016/0887-8994(85)90049-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A 15-year-old boy with diarrhea, dizziness, dysesthesias, and depression is described. On admission, his blood pressure was 110/84 reclining but less than 40 systolic while standing. Vibratory sensation and nerve conduction velocities were decreased in his lower extremities. CSF protein concentration was normal but sural nerve biopsy demonstrated generalized demyelination. Extensive toxicologic and metabolic screening proved unremarkable. Norepinephrine concentrations in plasma and urine, and CSF concentration of 3-methoxy-4-hydroxy phenylglycol (MHPG) were markedly reduced. The patient demonstrates a combination of autonomic dysfunction, peripheral neuropathy, and affective disorder. This collection of clinical and neurochemical findings represents a previously unreported entity involving a defect of both central and peripheral noradrenergic systems.
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Affiliation(s)
- S Rimar
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510
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Abstract
To further define the role of the neuromaturational examination in determining the presence of learning problems, we examined 104 boys, ages 9.5 to 14.1 years, representing three populations of school children: normal (32 boys), gifted (37), and learning disabled (35). Information concerning each child's behavior and development was obtained through a parent questionnaire; cognitive ability and academic achievement were measured by the Wechsler Intelligence Scales for Children (revised) and Woodcock -Johnson Psychoeducational Battery, respectively. Significant relationships emerged between the number of neuromaturational signs and data group membership (LD greater than N greater than G,P less than 0.05). The number of neuromaturational signs decreased with age for normal (P less than 0.05) and gifted (P less than 0.05) children, but not for the learning-disabled group. Tasks that differentiated the normal and learning disabled were entered into a stepwise discriminant analysis, with a resulting classification accuracy of 93.1% and 100% for the normal and learning-disabled boys, respectively. Analysis of covariance indicated that differences in performance of the three groups may reflect IQ differences among the populations. Learning disabled boys were more likely to exhibit synkinesis than normal boys, but gifted boys did not differ from the learning disabled in the frequency of synkinesis. Our data indicate that, although a composite set of neuromaturational tasks can discriminate normal and learning-disabled boys with a high level of accuracy, caution is urged because the findings may be more related to overall intelligence than to a specific learning disability.
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Abstract
Recent progress in the nosology of neuropsychiatric disorders in general, and attention deficit disorder in particular, have produced parallel advances in our understanding of the etiology of these disorders, enhanced their accurate recognition, and clarified appropriate management strategies. This article provides a detailed overview of these advances.
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Abstract
Evidence from both epidemiologic and pharmacologic investigations into the biology of attention deficit disorder suggests that abnormalities in neurotransmitter function exist in children with attention deficit disorder. This article reviews this evidence and discusses the limitations imposed upon such clinical investigations.
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