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This paper reports the first observation of quasi‐Bragg scattering from collimating Goebel mirrors in a real instrument. On the basis of the experimental data obtained and the numerical analysis performed, it is concluded that it is necessary to take into account the effect of quasi‐Bragg scattering when constructing real devices with multilayer mirrors for use in X‐ray diffractometry and in spectroscopy, especially for small‐angle scattering with position‐sensitive detectors. [ABSTRACT FROM AUTHOR]

This study compared two interventions: one focusing on language and storybook reading and the other on alphabetic skills and writing. Seventy-one preschoolers aged 3-5 from a low SES township in central Israel (35 in the reading program and 36 in the writing program) participated in evaluation of the interventions. Twenty-four untreated preschoolers served as a control group. The children were tested twice, at the beginning and at the end of the school year, in: phonological awareness, word writing, letter knowledge, orthographic awareness, listening comprehension, receptive vocabulary, and general knowledge. Both programs involved games and creative activities. The writing program encouraged letter knowledge, phonological awareness, and functional writing activities. The reading program utilized 11 children's books for focusing on language and exploring major concepts raised by these books. Results indicated that children in the two literacy programs progressed significantly more than the control group on phonological awareness and orthographic awareness. However, the joint writing group significantly outperformed both the joint reading group and the control group on phonological awareness, word writing, orthographic awareness, and letter knowledge. We also found that children as young as 3-4 years gained from literacy programs as much as did older children, aged 4-5, on all the measures assessed in our program.

The article focuses on dental implant-supported zirconia full-mouth rehabilitations have become a treatment option for patients with failing dentitions or edentulism. It mentions fabricating metal-ceramic or metal-acrylic restorations and number and position of implants and guided surgery and loading protocol and zirconia full-mouth restorations with reduced risk of chipping and fractures. It also mentions principles of porcelain-fused-to-metal and porcelain-fused-to-zirconia restorations.

The M and S molecular forms of Anopheles gambiae are undergoing speciation as they adapt to heterogeneities in the environment, spreading malaria in the process. We hypothesized that their divergence despite gene flow is facilitated by reduced recombination at the centromeric (proximal) end of the X chromosome. We sequenced introns from 22 X chromosome genes in M and S from two locations of West Africa where the forms are sympatric. Generally, in both forms nucleotide diversity was high distally, lower proximally, and very low nearest the centromere. Conversely, differentiation between the forms was virtually zero distally and very high proximally. Pairwise comparisons to a close relative, the sibling species Anopheles arabiensis, demonstrated uniformly high divergence regardless of position along the X chromosome, suggesting that this pattern is not purely mechanical. Instead, the pattern observed for M and S suggests the action of divergent natural selection countering gene flow only at the proximal end of the X chromosome, where recombination is reduced. Comparison of sites with fixed differences between M and S to the corresponding sites in A. arabiensis revealed that derived substitutions had been fixed in both forms, further supporting the hypothesis that both have been under selection. These derived substitutions are fixed in the two West African samples and in samples of S from western and coastal Kenya, suggesting that selection occurred before the forms expanded to their current ranges. Our findings are consistent with a role for suppressed genetic recombination in speciation of A. gambiae. gene flow | natural selection | polymorphism | recombination reproductive isolation

Emerging species within the primary malaria vector Anopheles gambiae show different ecological preferences and significant prezygotic reproductive isolation. They are defined by fixed sequence differences in X-linked rDNA, but most previous studies have failed to detect large and significant ifferentiation between these taxa elsewhere in the genome, except at two other loci on the X chromosome near the rDNA locus. Hypothesizing that this pericentromeric region of the X chromosome may be accumulating differences faster than other regions of the genome, we explored the pattern and extent of differentiation between A. gambiae incipient species and a sibling species, A. arabiensis, from Burkina Faso, West Africa, at 17 microsatellite loci spanning the X chromosome. Interspecific differentiation was large and significant across the entire X chromosome. Among A. gambiae incipient species, we found some of the highest levels of differentiation recorded in a large region including eight independent loci near the centromere of the X chromosome. Outside of this region, no significant differentiation was detected. This pattern suggests that selection is playing a role in the emergence of A. gambiae incipient species. This process, associated with efficient exploitation of anthropogenic modifications to the environment, has public health implications as it fosters the spread of malaria transmission both spatially and temporally.

Abstract: The spinal muscular atrophy (SMA) associated protein survival of motor neuron (SMN) is known to be a moonlighting protein: having one primary, ancestral function (presumed to be involvement in U snRNP assembly) along with one or more secondary functions. One hypothesis for the evolution of moonlighting proteins is that regions of a structure under relatively weak negative selection could gain new functions without interfering with the primary function. To test this hypothesis, we investigated sequence conservation and dN/dS, which reflects the selection acting on a coding sequence, in SMN and a related protein, splicing factor 30 (SPF30), which is not currently known to be multifunctional. We found very different patterns of evolution in the two genes, with SPF30 characterized by strong sequence conservation and negative selection in most animal taxa investigated, and SMN with much lower sequence conservation, and much weaker negative selection at many sites. Evidence was found of positive selection acting on some sites in primate genes for SMN. SMN was also found to have been duplicated in a number of species, and with patterns that indicate reduced negative selection following some of these duplications. There were also several animal species lacking an SMN gene. [Copyright &y& Elsevier]

The C-Terminal Domain (CTD) of the large subunit (Rpb1) of RNA Polymerase II has a Tyrosine-Serine-Proline-Threonine-Serine-Proline-Serine repeat structure in many eukaryotes. Chemical modifications of these residues play a central role in the regulation and coordination of the events of transcription. However, substantial variability in the presence and regularity of repeat arrays exists between eukaryote taxa. Following a survey of CTD structure from diverse eukaryote species, two hypotheses were tested relating to repeat structure and the action of selection on the CTD. First, it was found that degenerated repeat structure is associated with lower serine and proline frequencies in some eukaryote taxa but not in others. Second, maximum likelihood models of the evolution of Rpb1 in a number of species groups found that purifying selection on the non-repetitive CTD of several Leishmania species was substantially lower than for the rest of Rpb1, whereas purifying selection in a number of species groups containing repeat arrays was usually as high or nearly as high as for the rest of Rpb1. Characterization of CTD structure for a larger number of species than has been completed previously also revealed a greater diversity of CTD structures in eukaryotes than previously known, along with loss of repeat structure in the animals and fungi, two taxa where it has not previously been known. These results suggest that loss of CTD repeat structure has been an important aspect of RNA Polymerase II evolution in diverse eukaryotes. [ABSTRACT FROM AUTHOR]

Many mycophagous species of Drosophila can tolerate the mushroom poison α-amanitin in wild mushrooms and in artificial diet. We conducted feeding assays with sixteen Drosophila species and α-amanitin in artificial diet to better determine the phylogenetic distribution of this tolerance. For eight tolerant and one related susceptible species, we sequenced the gene encoding the large subunit of RNA Polymerase II, which is the target site of α-amanitin. We found no differences in the gene that could account for differences in susceptibility to the toxin. We also conducted feeding assays in which α-amanitin was combined with chemical inhibitors of cytochrome P45Os or glutathione S-transferases (GSTs) in artificial diet to determine if either of these enzyme families is involved in tolerance to α-amanitin. We found that an inhibitor of GSTs did not reduce tolerance to α-amanitin, but that an inhibitor of cytochrome P450s reduced tolerance in several species. It is possible that the same cytochrome P450 activity that produces tolerance of α-amanitin might produce tolerance of other mushroom toxins as well. If so, a general detoxification mechanism based on cytochrome P450s might answer the question of how tolerance to α-amanitin arose in mycophagous Drosophila when this toxin is found in relatively few mushrooms. [ABSTRACT FROM AUTHOR]

Two scales of mothers' mediation of their children's writing based on Aram and Levin (2001) were developed and tested in 67 mother-child Hong Kong Chinese dyads in three grade levels - second-year kindergarten, third-year kindergarten, and first grade. With children's ages, grades, and non-verbal IQs, as well as mothers' education levels statistically controlled in a regression equation, the four strategies of the 'Print Mediation' scale, a measure of mother-child joint writing productions, explained a unique 10% of the variance in children's word reading. These four strategies tended to change with age such that higher autonomy was more common among older children and lower autonomy was more prevalent among younger children. In a separate hierarchical regression equation, the 'Literate Mediation' scale, tapping specific writing strategies, explained a unique 8-11% of the variance in children's word reading. A prevalence of copying strategies tended to be negatively associated with reading skill and a prevalence of morphologically based strategies tended to be positively associated with reading skill, even apart from age and grade level. Findings demonstrate some strong developmental trends in the writing process but also suggest that a more analytic approach to Chinese character writing may be helpful for literacy development, even among the youngest children. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated mother-child storybook telling and joint writing as predictors of early literacy among kindergartners with hearing loss. Method: Participants were 30 Israeli kindergartners with hearing loss and their mothers. Early literacy assessments tapped children's alphabetic skills (e.g., word writing, word recognition, and letter knowledge) and linguistic skills (e.g., phonological awareness, general knowledge, and receptive vocabulary). Each mother told her child the story of a wordless book and helped her child write words. Both interactions were videotaped and analyzed. Results: Our major findings showed that maternal storybook telling correlated with linguistic skills, and maternal writing mediation correlated with basic alphabetic skills. A series of 3-step hierarchical regression analyses revealed that beyond children's age, children's degree of hearing loss, and joint writing, storybook telling predicted children's phonological awareness (22%), general knowledge (28%), and receptive vocabulary (18%). Beyond children's age, children's degree of hearing loss, and storybook telling, joint writing, predicted word writing (15%), word recognition (31%), and letter knowledge (36%). Implications: Recommendations focused on encouraging parent and teacher awareness about the differential contributions of storybook telling and writing mediation to early literacy. We also advocated enhancing parents' skills for promoting children's literacy. [ABSTRACT FROM AUTHOR]

The current study examined the early literacy skills of kindergartners with hearing loss who were enrolled in individual inclusion or group inclusion programs as well as those of children with typical hearing. We also examined the relationship between early literacy skills and background variables such as degree of hearing loss, type of sensory aid used, age at onset of rehabilitation and family's socioeconomic status. Forty-two children participated: 16 were children with hearing loss in a group inclusive program, 15 were children with hearing loss in an individual inclusive program and 11 were children with typical hearing. We evaluated the following early literacy skills: word identification, writing level, phonological awareness, letter identification, orthographic awareness, general knowledge and vocabulary. Main findings indicated that children with hearing loss in the individual inclusive program yielded better achievements compared to those enrolled in the group inclusive program regarding phonological awareness, letter identification, general knowledge and vocabulary. Achievements of children with typical hearing in these parameters surpassed those of children with hearing loss in either of the inclusive programs. No statistically significant differences emerged between individual and group inclusive programs regarding reading, writing or orthographic awareness. Achievements of the hearing children in these parameters surpassed those enrolled in group inclusion but did not differ statistically from those enrolled in individual inclusion. Our findings showed a negative correlation between general knowledge and degree of hearing loss. Also, general knowledge, reading and writing correlated with age at onset of rehabilitation; no correlation emerged between socioeconomic status and children's early literacy skills. The results suggest that gaps in the academic achievements associated with literacy between children with and without hearing loss, as well as between children with hearing loss enrolled in different inclusive programs, already appear in kindergarten. Focusing on training and improvement of pre-literacy capabilities in kindergarten may decrease those gaps. [ABSTRACT FROM AUTHOR]

The condition of hyperlexia, often associated with autism, is a rare disorder in which children read words precociously but show little comprehension, markedly poor language, behavioral, and interpersonal skills. The relationship of hyperlexia and dyslexia has never been investigated, although suggestions have been made that the two conditions may be related. In light of current research on familial factors in autism, language disorder, dyslexia, and, recently, hyperlexia, this study investigated family histories of twelve hyperlexic children in regard to language, reading, writing, spelling, and other learning problems, handedness, and presence of allergies. Results suggest a distinct familial tendency to disorders of language, reading, writing, and spelling in male relatives, along with an unusually high instance of nonleft-handedness. Allergy information is inconclusive. Descriptive data are presented, and the relationship of symptomatology in hyperlexia and dyslexia is described and discussed. It is suggested that hyperlexia may represent a point of convergence of several genetically-linked developmental disorders. [ABSTRACT FROM AUTHOR]

School counselors' occupational plans were investigated in terms of the mediating role of occupational self-efficacy including three antecedents (role clarity, role autonomy, social support) on three outcomes (life satisfaction, job satisfaction, occupational plans) among 483 female Israeli school counselors, aged 26-69. High levels of the three antecedents were associated with high levels of occupational self-efficacy, which in turn was associated with high levels of life and job satisfaction and with counselors' plans to remain in their profession. The antecedents also demonstrated direct effects with job satisfaction. This emphasizes the importance of occupational self-efficacy in counselor retention and its antecedents., (© The Author(s), under exclusive licence to Springer Nature B.V. 2021.)

The current study examines the nature and variability of parents' aid to preschoolers in the context of a shared writing task, as well as the relations between this support and children's literacy, vocabulary, and fine motor skills. In total, 135 preschool children (72 girls) and their parents (primarily mothers) in an ethnically diverse, middle-income community were observed while writing a semi-structured invitation for a pretend birthday party together. Children's phonological awareness, alphabet knowledge, word decoding, vocabulary, and fine motor skills were also assessed. Results revealed that parents provided variable, but generally low-level, support for children's approximation of sound-symbol correspondence in their writing (i.e., graphophonemic support), as well as for their production of letter forms (i.e., print support). Parents frequently accepted errors rather than asking for corrections (i.e., demand for precision). Further analysis of the parent-child dyads ( n = 103) who wrote the child's name on the invitation showed that parents provided higher graphophonemic, but not print, support when writing the child's name than other words. Overall parental graphophonemic support was positively linked to children's decoding and fine motor skills, whereas print support and demand for precision were not related to any of the child outcomes. In sum, this study indicates that while parental support for preschoolers' writing may be minimal, it is uniquely linked to key literacy-related outcomes in preschool.

Parental writing support was examined over time and in relation to children's language and literacy skills. Seventy-seven parents and their preschoolers were videotaped writing an invitation together twice during one year. Parental writing support was coded at the level of the letter to document parents' graphophonemic support (letter-sound correspondence), print support (letter formation), and demand for precision (expectation for correcting writing errors). Parents primarily relied on only a couple print (i.e., parent writing the letter alone) and graphophonemic (i.e., saying the word as a whole, dictating letters as children write) strategies. Graphophonemic and print support in preschool predicted children's decoding skills, and graphophonemic support also predicted children's future phonological awareness. Neither type of support predicted children's vocabulary scores. Demand for precision occurred infrequently and was unrelated to children's outcomes. Findings demonstrate the importance of parental writing support for augmenting children's literacy skills.

Does learning to read influence one's visual skill? In Study 1, kindergartners from Hong Kong, Korea, Israel, and Spain were tested on word reading and a task of visual spatial skill. Chinese and Korean kindergartners significantly outperformed Israeli and Spanish readers on the visual task. Moreover, in all cultures except Korea, good readers scored significantly higher on the visual task than did less good readers. In Study 2, we followed 215 Hong Kong Chinese kindergartners across 1year, with word reading and visual skills tested twice. In this study, word reading at Time 1 by itself predicted 13% of unique variance in visual skill at Time 2. Together, these results underscore the potential importance of the process of learning to read for shaping one's visual spatial skill development., (Copyright © 2010 Elsevier Inc. All rights reserved.)

The present study examined invented spelling of pinyin (a phonological coding system for teaching and learning Chinese words) in relation to subsequent Chinese reading development. Among 296 Chinese kindergartners in Beijing, independent invented pinyin spelling was found to be uniquely predictive of Chinese word reading 12 months later, even with Time 1 syllable deletion, phoneme deletion, and letter knowledge, in addition to the autoregressive effects of Time 1 Chinese word reading, statistically controlled. These results underscore the importance of children's early pinyin representations for Chinese reading acquisition, both theoretically and practically. The findings further support the idea of a universal phonological principle and indicate that pinyin is potentially an ideal measure of phonological awareness in Chinese.

The M and S molecular forms of Anopheles gambiae are considered to be incipient species, despite residual gene exchange. Of the three small genome regions that are strongly differentiated between the molecular forms ("speciation islands"), two are located near centromeres, on the left arm of chromosome 2 and the X chromosome. To test the prediction of reduced recombination in these islands, we estimated recombination rates between microsatellite loci on the X chromosome using two M-form strains. Across most of the chromosome, recombination occurred at approximately 1 centimorgan per megabase (cM Mb(-1)), a value closely matching the genome-wide average estimated for A. gambiae and for other eukaryotes. Recombination was much higher at the telomeric end, > 7 cM Mb(-1). In the speciation island at the centromeric end, recombination was sharply reduced to approximately 0.2 cM Mb(-1), consistent with a role for reduced recombination in maintaining differentiation between nascent species despite gene flow.

Permethrin and DDT resistance in Anopheles gambiae s.s. associated with a leucine-serine knockdown resistance (kdr) mutation in the voltage-gated sodium channel gene was discovered recently in western Kenya where a large scale permethrin-impregnated bed net (ITN) program has been implemented. Collections of An. gambiae s.l. were made from intervention and control villages prior to and after onset of the program. The kdr genotypes were determined using allele-specific polymerase chain reaction diagnostic tests. In An. gambiae s.s., the frequency of the kdr mutation prior to ITN introduction was approximately 3-4% in western Kenya and zero in samples from the coast. After ITN introduction, the kdr mutation increased in ITN and neighboring villages from approximately 4% to approximately 8%, but remained unchanged in villages at least 20 km distant and was not detected in coastal Kenya. The identical leucine-serine mutation was found in a single An. arabiensis individual among 658 tested. The leucine-phenylalanine kdr mutation common in west African An. gambiae populations was not detected in An. gambiae s.l. from Kenya. Implications for the population structure and control of An. gambiae are discussed.

Twenty-four children (4-17 years) with unilateral left (N = 14) or right (N = 10) hemisphere damage and 24 age-matched controls were tested on their ability to presuppose the truth of factive sentences e.g., "Max knew that he locked the door," and to infer the truth or falsity of implicative sentences "Max remembered to lock the door." Experimental sentence types varied according to the type of inference, the semantic features of the verb (factive vs. implicative), the presence and type of negation (lexical or syntactic), and the syntax of the complement (tensed or infinitive). Relative to age-matched controls, left lesion subjects were deficient in both their presupposition and implication performance, particularly when such inferences required the computation of negation scope. Right lesion subjects exhibited a somewhat more selective deficit; one limited to implication, but not presupposition, and one limited to lexical but not syntactic forms of negation.

This second paper in a series on developmental apraxia of speech (DAS) (Shriberg, Aram, & Kwiatkowski, 1997a) reports findings from two studies. Study I compares speech and prosody-voice profiles of a group of 14 children with suspected DAS to profiles of 73 children with speech delay (SD). Results suggest that the only linguistic domain that differentiates some children with suspected DAS from those with SD is inappropriate stress. Study II cross-validates these findings, using retrospective data from a sample of 20 children with suspected DAS evaluated in a university phonology clinic over a 10-year period. Discussion considers methodological and conceptual issues in the measurement of linguistic stress. Theoretical issues and implications for research and clinical practice are deferred for synthesis of the present findings with those from a multi-site cross-validation project (Shriberg, Aram, & Kwiatkowski, 1997b).

Developmental apraxia of speech (DAS) is a putative diagnostic category for children whose speech errors presumedly (a) differ from the errors of children with developmental speech delay (SD) and (b) resemble the errors of adults with acquired apraxia of speech. The studies reported in this series (Shriberg, Aram, & Kwiatkowski, 1997a, 1997b) concern both premises, with primary focus on the first--that children with DAS can be differentiated from children with SD on the basis of one or more reliable differences in their speech error profiles. Immediate goals are to identify a diagnostic marker for DAS and to consider implications for research and clinical practice. A long-term goal is to identify the phenotype marker for DAS, on the assumption that it may be a genetically transmitted disorder. This first paper reviews relevant descriptive and theoretical perspectives. Findings from a local ascertainment study support the clinical functionality of the term suspected DAS.

Two prior studies in this series (Shriberg, Aram, & Kwiatkowski, 1997a, 1997b) address the premise that children with developmental apraxia of speech (DAS) can be differentiated from children with speech delay (SD) on the basis of one or more reliable differences in their speech. The first study compared segmental and prosody-voice profiles of a group of 14 children with suspected DAS to profiles of 73 children with SD. Results suggest that the only linguistic domain that differentiates some children with suspected DAS from those with SD is inappropriate stress. The second study cross-validated these findings, using retrospective data from a sample of 20 children with suspected DAS evaluated in a university phonology clinic over a 10-year period. The present study is of particular interest because it cross-validates the prior stress findings, using conversational speech samples from 19 children with suspected DAS provided by five DAS researchers at geographically diverse diagnostic facilities in North America. Summed across the three studies, 52% of 48 eligible samples from 53 children with suspected DAS had inappropriate stress, compared to 10% of 71 eligible samples from 73 age-matched children with speech delay of unknown origin. Discussion first focuses on the implications of stress findings for theories of the origin and nature of DAS. Perspectives in psycholinguistics, neurolinguistics, and developmental biolinguistics lead to five working hypotheses pending validation in ongoing studies: (a) inappropriate stress is a diagnostic marker for at least one subtype of DAS, (b) the psycholinguistic loci of inappropriate stress in this subtype of DAS are in phonological representational processes, (c) the proximal origin of this subtype of DAS is a neurogenically specific deficit, (d) the distal origin of this form of DAS is an inherited genetic polymorphism, and (e) significant differences between acquired apraxia of speech in adults and findings for this subtype of DAS call into question the inference that it is an apractic, motor speech disorder. Concluding discussion considers implications of these findings for research in DAS and for clinical practice.

Criteria for identification of children as specifically language impaired (SLI) vary greatly among clinicians and researchers. Standardized psychometric discrepancy criteria are more restrictive and perhaps less sensitive to language impairment than is clinical judgment based on a child's language performance in naturalistic contexts. This paper examines (a) differences in groups of preschool children clinically diagnosed as SLI who were and were not identified as SLI through standard psychometric discrepancy criteria, and (b) the validity of quantitative measures of mean length of utterance (MLU), syntax, and pragmatics derived from a spontaneous language sample as criteria for discriminating clinically diagnosed preschoolers from normally developing preschoolers. Spontaneous language data indicated that children clinically identified as SLI produced a significantly higher percentage of errors in spontaneous speech than normal children whether they met psychometric discrepancy criteria or not. Logistic regression analysis indicated that a combination of MLU, percent structural errors, and chronological age was the optimal subset of variables useful for predicting a clinical diagnosis of SLI. This combined criterion captured a larger proportion of the clinically identified SLI children than even the best psychometric discrepancy criteria.

The hypothesis of unilateral left hemisphere damage as an explanatory model for the neurological basis of specific language impairment (SLI) does not appear to be sufficient for most children with SLI. Children with unilateral brain lesions have been shown to function significantly lower than their neurologically intact peers on a variety of language measures, yet few of the deficits noted are as persistent or severe as those seen in SLI. In at least two instances, however, language symptomatology following unilateral lesions in children does parallel some types of SLI. The first occurs following subcortical damage to anterior grey and white matter structures that typically results in pronounced language and learning disorders. The second parallel lies in the similar developmental course shared by children with "delayed" language and children with known unilateral lesions, whereby language onset and development is slow in the preschool years but normalizes by school age, with minimal long-term language-learning deficits.

Twenty-five children with early left (LL = 16) or right (RL = 9) hemisphere damage and 25 age-matched controls were tested on their comprehension and imitation of complex coordinate, passive, and relative clause structures using a matched experimental design. The predominant deficit exhibited by left-injured children was one of significantly impaired imitation coupled with relatively preserved comprehension. For RL subjects the deficit was less pronounced in either comprehension or imitation. Manipulation of surface and configurational features of sentence structure revealed task differences in the pattern of correct performance; however, error strategies observed across the two methodologies were shown to converge in a number of critical ways, as well as to replicate those previously obtained with adult aphasics. The results are interpreted as consistent with an early and continuous left hemisphere specialization for expressive syntax.

In this paper we report on the longitudinal stability of IQ in 26 children with unilateral left (LL N = 18) or right (RL N = 8) hemisphere damage. Results revealed (i) normal or near normal levels of intellectual performance in both LL and RL groups, and, (ii) hemispheric differences in the level and stability of intellectual performance. RL children achieved lower IQ scores than LL children and were more likely to decrease in VIQ over time. Cross-sectional analyses revealed a tendency for injury sustained earlier (e.g. during the first 5 years of age), rather than later in development to be associated with lower IQ scores.

This paper reports on the results of a large multicenter project designed to develop an empirically based classification of preschool children with language impairments. A clinically selected population of 252 children with specific language impairments (SLI) was used to evaluate the reliability, coverage, and usefulness of both standard clinical and research definitions of such children. Varying degrees of congruence were found between the clinically identified children with SLI and those identified as SLI using discrepancy, deficit, and standardized operational criteria. Such mismatch between the original clinical identification and more standardized operational criteria may be related to different clinical perspectives, professional training, and limited assessment measures. These results suggest that there is a significant gulf between the clinical diagnosis of children with specific language impairment and more standardized operational criteria. It is suggested that the global concept of a "specific language impairment" may not be a useful concept for either clinical or research activities.

The present investigation addresses two primary hypotheses: (a) that a subset of children with developmental language disorders exhibits significantly more disfluencies than other children with language disorders and (b) that differences between the disfluent and nondisfluent groups observed in fluency may be related to differences in language deficits. Spontaneous language samples from 60 preschool children with developmental language disorders were analyzed for frequency and type of disfluencies. Comparisons of the frequency of disfluencies across subjects revealed that a subset of 10 subjects exhibited significantly more disfluencies than the other subjects with language disorders. Demographic, intelligence, and language variables were compared across the two groups to determine whether such factors could account for the differences in fluency. The subjects with greater percentages of disfluencies were found to be significantly older and demonstrated significantly higher scores on two standard measures of vocabulary. These findings were interpreted in light of two models of disfluencies: the neuropsycholinguistic (Perkins, Kent, & Curlee, 1991) and Demands and Capacities (Adams, 1990; Starkweather, 1987). This suggests that some children with language disorders are at risk for fluency breakdown because of dysynchronies in the development of lexical and syntactic aspects of language or as a result of mismathces between speaking demands and capacities.

We tested the hypothesis that very low birth weight (VLBW < 1.5 kg) children would have significantly poorer neurocognitive abilities at school age than would normal birth weight full-term age mates, that differences would persist after control for neurologic impairment and social risk, and that VLBW would interact with social risk. Two hundred forty-nine VLBW children and a randomly selected sample of 363 normal birth weight age mates born 1977 through 1979 were tested at 8 years. A neurologic examination and tests of intelligence, language, speech, reading, mathematics, spelling, visual and fine motor abilities, and behavior were performed. Twenty-four (10%) VLBW had a major neurologic abnormality compared with none of the controls. VLBW had significantly poorer scores on all tests, with the exception of speech and the total behavior score. These differences persisted among VLBW children without major neurologic abnormality, with the exception of social competence, reading, and spelling. Even normal IQ, neurologically normal VLBW had significantly poorer scores than did controls in expressive language, memory, visuomotor, and fine motor function, and measures of hyperactivity. When social risk was controlled in multiple regression analyses, VLBW still had an adverse effect on all outcome measures with the exception of speech. Social risk was, however, the major determinant of outcome. We found an interaction between VLBW and social risk only in verbal IQ and in the opposite direction than hypothesized.

Empirical data from two studies address the clinical validity of discrepancy criteria for identification of children with developmental language disorders (DLD). Study 1 involved 256 preschoolers clinically defined as DLD and meeting inclusionary criteria for normal hearing, intellectual, neurological, and psychiatric status. Application of alternative psychometrically derived discrepancy criteria identified only 40% to 60% of the clinically defined group as language disordered. Study 2 applied nonverbal IQ-language performance discrepancy criteria to 368 eight-year-old, randomly selected control subjects, resulting in over 45% of the controls being identified as DLD. Factors contributing to underidentification in Study 1 and over-identification in Study 2 are discussed, raising questions regarding the validity of discrepancy criteria for identification of DLD children.

Children and adolescents with unilateral left- or right-hemisphere lesions were administered a standardized test of mathematics ability and a battery of experimental tests that examined the components of numerical and arithmetic processing. All lesioned groups showed at least marginally lower scores on the standardized test than the controls. More importantly, lesion-related deficits in performance were observed, especially for younger left-lesioned subjects (ages 7-12), on the verbal counting, digit matching, speeded addition, and written subtraction tasks; deficits among younger right-lesioned subjects were similar in nature, yet less pronounced than in the left-hemisphere group. Older left-lesioned subjects showed differences from their controls only on complex verbal counting and speeded addition. Correlations among the various measures indicated two further points. First, earlier onset of left-hemisphere lesion is associated with more serious disruption of mathematical processing. Second, these disruptions are not well assessed by a typical standardized test of mathematical performance, but are clearly in evidence with more precise, focused tasks.

Fifty-six very low birth weight infants (less than 1.5 kg) were followed until 8 y of age to see if predischarge auditory brainstem response (ABR) results were predictive of neurobehavioral development. The results suggest that early ABR may predict subsequent performance on measures of intelligence quotient, language, and reading. Unilateral ABR abnormalities did not appear predictive, but bilateral abnormalities did. Analysis of a variety of neonatal risk factors in conjunction with early ABR and hearing loss with respect to educational outcome was also undertaken.

Very low birthweight (VLBW) is often considered to be a risk factor for speech and language disorders, yet data are equivocal. The present study compared speech and language comprehension and production between 249 very-low-birthweight (VLBW: less than 1.5 kg) and 363 normal-birthweight 8-year-olds, randomly sampled in a geographic area. Mean performance for the entire group of VLBW children and for the group when 24 VLBW children with major neurologic abnormalities were excluded, was significantly lower than for controls on the majority of speech and language measures. Further analyses addressed the clinical significance of these statistically significant differences. Test scores were converted to standard scores and grouped according to standard deviation intervals, thus portraying each child's performance in terms of the magnitude of discrepancy from each test's mean. When the 24 children with major neurological abnormalities were excluded, no significant differences between the VLBW and control children were observed. Using discrepancy between WISC-R performance IQ and language to define specific language impairment (SLI), a higher percentage of control than VLBW children were identified as having SLI. Neonatal risk factors did not differentiate between VLBW children with or without SLI. A higher proportion of VLBW than control children did present subnormal language associated with IQ less than 85, hearing deficits, and/or major neurological impairments. Thus, SLI is not more common among VLBW than control children. Language deficits accompanied by more general developmental problems, however, are more frequent.

We reviewed the presentations, clinical courses, and outcomes of 42 children with unilateral hemispheric stroke. Infants with strokes identified within the first few days of life usually presented with seizures. These infants had few abnormal neurologic findings as neonates, but hemiparesis became evident as gross motor development proceeded. Infants with strokes identified later in the first year of life usually presented with pathologic early hand preference without a history of an ictus. During subsequent development, the motor deficits in these children became more evident, producing an apparent progression of the neurologic abnormalities. Strokes identified in older children typically presented as sudden hemiparesis, often associated with seizures. The hemiparesis in these children was most severe at the onset, followed by some improvement in strength in all patients. Functional outcome was variable. At last follow-up, all children were ambulatory, some with clinically apparent hemiparesis. Eight of the 42 children (19%) developed recurrent seizures with an onset ranging from 4 months to more than 10 years (median: 26 months) after the stroke.

Background: We tested the hypothesis that very-low-birth-weight (less than 1.5 kg) infants with perinatal growth failure whose head size is not normal by eight months of age (corrected for prematurity) have significantly poorer growth and neurocognitive abilities at school age than very-low-birth-weight children with a normal head size at eight months. We also hypothesized that these differences would persist even after control for major neurologic impairment and perinatal and sociodemographic risk factors., Methods: We have followed a cohort of very-low-birth-weight children since their birth during the period 1977 to 1979. At eight to nine years of age 249 children were evaluated with a neurologic examination and tests of intelligence; receptive and expressive language skills; speech, reading, mathematics, and spelling aptitude; visual and fine motor abilities; and behavior. Ages were corrected for premature birth., Results: Among these 249 very-low-birth-weight children, head size was subnormal (less than the mean -2 SD for age) at birth in 30 (12 percent), at term in 57 (23 percent), and at eight months in 33 (13 percent). As compared with the 216 children with normal head sizes, the 33 children with subnormal head sizes at the age of eight months had significantly lower mean birth weights (1.1 vs. 1.2 kg) and higher neonatal risk scores (71 vs. 53) and at the age of eight years had a higher incidence of neurologic impairment (21 percent vs. 8 percent) and lower IQ scores (mean verbal, 84 vs. 98). Even among the children without neurologic abnormalities, a subnormal head size at eight months of age was predictive of poorer verbal and performance IQ scores at eight years of age; lower scores for receptive language, speech, reading, mathematics, and spelling; and a higher incidence of hyperactivity. In multiple regression analyses to control for socioeconomic and neonatal risk factors, intrauterine growth failure, birth weight, and neurologic impairment, a subnormal head size at eight months of age had an independently adverse effect on IQ and on scores for receptive language, speech, reading, and spelling., Conclusions: In very-low-birth-weight infants, perinatal growth failure, as evidenced by a subnormal head circumference at eight months of age, is associated with poor cognitive function, academic achievement, and behavior at eight years of age.

Early lexical development in 27 children with focal brain injury was studied cross-sectionally and longitudinally. Data were obtained from children between 12 and 35 months of age who acquired their lesion prenatally or within the first 6 months of life. Results for the group as a whole provide clear evidence for delays in lexical comprehension and production, and for a larger number of comprehension/production dissociations than would be expected by chance. In addition, a significant number of children were observed having unusual difficulty mastering predication and/or using an atypically high proportion of closed class words (suggesting reliance on holistic/formulaic speech). Analyses by lesion type revealed no effect of lesion size. Analyses according to side of lesion revealed that children with right-hemisphere damage produced a higher proportion of closed class words, suggesting heavy reliance on well-practiced but under-analyzed speech formulae. Children with left-hemisphere damage were slightly better in comprehension than children with right-hemisphere damage. In addition, left posterior lesions were associated with greater delays in expressive language, and delays were more protracted in children with left posterior damage. No differential effects of left posterior damage were found for lexical comprehension.

An evoked potentials procedure that has repeatedly provided evidence of predominant right-hemisphere engagement during language tasks in recovered adult aphasics was applied to the study of 14 children with early unilateral left-hemisphere lesions and in 14 matched normal subjects. In contrast with the adult patients, the children with left-hemisphere lesions displayed the normal pattern of predominant left-hemisphere engagement in visuospatial tasks. These data suggest that language restitution and development following early lesions involves intrahemispheric rather than interhemispheric functional reorganization.

The spontaneous conversational speech of 20 children with unilateral left hemisphere lesions and 13 with right lesions was compared to normally developing peers matched by age, sex, race, and social class for instances of stuttering type nonfluencies, normal nonfluencies, and rate of speech. Both left and right lesioned children provided quantitatively more and qualitatively different patterns of nonfluencies than their neurologically normal peers. Left and right lesioned children produced more stuttering types of nonfluencies than their controls, but neither lesioned group produced a greater number of normal nonfluencies than controls. Left lesioned children also had a slower rate of speech as measured by number of syllables per second during either stuttered or fluent speech. Considerable variability was observed among lesioned children. Implications for neurogenic theories of developmental fluency disorders are discussed.

Language, intelligence, academic achievement, and behavioral adjustment were assessed in a group of 20 adolescents originally studied 10 years earlier as preschoolers with language disorders. At follow-up, 20% had WISC-R IQ scores in the mentally deficient range and were being educated in EMR classrooms. Of the remaining 16, 11 (69%) had required special tutoring, grade retention, or LD class placement. The majority of non-EMR subjects continued to evidence persistent deficits in language and academic achievement and were rated by their parents as being less socially competent and having more behavioral problems than their peers. Of the initial preschool measures available, the Leiter was found to be the best single predictor of intelligence, language, class placement, and reading achievement in adolescence, although the NSST: Expressive subtest also was a strong predictor of adolescent language.

Neurologic complications are a known and at times tragic consequence of cardiac catheterization. During a four-year period, 1,362 procedures were performed at our institution on children less than 15 years of age. Eighteen children, without prior nervous system disease, developed neurologic sequelae within 24 hours of cardiac catheterization (1.3%). Three presented with seizures only, ten with neurologic deficits, and five with both focal seizures and stroke. Computerized tomography scans (16 patients) demonstrated areas of nonhemorrhagic infarction in all but one. The 18 patients were studied retrospectively for possible factors contributing to the neurologic complications. They were matched to controls by age, cardiac lesion, and catheterization technique. Data examined included catheterization duration and approach, contrast agent, precatheterization urine specific gravity, pre- and postcatheterization hematocrit, blood loss, and intracatheterization events. Catheter and catheter sheath clots were noted in both patient groups. The neurologic complication group had 7/18 intracatheterization neurologic events versus only one in the controls and the change in hematocrit was greater in the complication group (t = 2.89, p less than 0.01). Due to this study's results and to prevent possible thromboembolic events, a heparinization protocol was instituted and patients were prospectively observed for neurologic complications. No neurologic complications have occurred over three years since the institution of this protocol.

Comprehension of connected language as assessed by the Revised Token Test (RTT) was studied in 17 children with left hemisphere lesions (LL) and 11 with right hemisphere lesions (RL). LL children's significantly lower performance on several subtests than left controls (LC) matched by age, sex, race, and social class appeared to be related to the memory demands of these subtests rather than the limited syntactic elements assessed by the RTT. LL subjects requested significantly more command repetitions than control or RL subjects and when a repetition was not requested LL subjects often responded with immediacy. Although RL children tended to perform lower than right matched controls (RC), these differences were not significant nor readily related to either the memory or specific linguistic structures assessed. RL subjects required fewer command repetitions than LL subjects and exhibited a significantly greater frequency of immediate responses than controls or LL subjects. While based on few children, a trend for LL children with retrorolandic lesions to perform more poorly than those with left prerolandic lesions was suggested. No systematic difference in performance was apparent for children with left cortical vs. left subcortical lesions or among discrete sites of lesions within the right hemisphere. Children with left lesions prior to 1 year of age performed no better and, in several instances, significantly poorer than LL patients sustaining lesions after 1 year of age. Among RL subjects, those sustaining lesions after 1 year of age had greater difficulty than those with lesion onset before 1 year of age, especially on linguistic elements which seemed to be dependent upon visual spatial properties. Further studies are needed to evaluate the comprehension of more complex linguistic structures among children with unilateral brain lesions as well as to study the role of more basic factors such as memory and attention in explaining the present findings.

The handedness and sex of 4- and 5-year-old children with developmental language disorders were studied through a comparison of language disordered children and a normal control group and through a comparison of six linguistically homogeneous subgroups of language disordered children. Differences between the handedness of a generalized language disordered group and a normal control group were not found, possibly due to the multiple etiologies of developmental language disorders. Children with severe language disorders, however, were non-right-handed more often than children with mild language disorders. Furthermore, certain types of linguistic deficits were associated with non-right-handedness, whereas age and cognitive abilities were not. Males were more often language disordered than females; however, sex ratios did not significantly differ among the subgroups, possibly due to the small number of language disordered females in this study. Implications for cerebral laterality in developmental language disorders are discussed.