Association between urinary 2-hydroxyethyl mercapturic acid and dyslexia among school-aged children.

Ethylene oxide is commonly used in industrial synthesis and medical disinfection. It is a known human carcinogen and has neurotoxicity. However, the association between ethylene oxide exposure and neurodevelopmental disorders remains unclear. This study aimed to evaluate the association between urinary concentrations of 2-hydroxyethyl mercapturic acid (HEMA; metabolite of ethylene oxide) and dyslexia among school-aged children. A total of 355 dyslexic children and 390 controls from three cities in China were enrolled in this case-control study from November 2017 to December 2020. Urinary HEMA was detected in 100% of the urine samples, suggesting widespread exposure to ethylene oxide in the children. Notably, the children with dyslexia had higher concentrations of urinary HEMA compared to the controls (geometric mean: 2.92 vs. 2.47 ng/mL) (P = 0.004). In the multivariable-adjusted model, urinary concentrations of HEMA were significantly associated with dyslexia risk. The individuals within the highest HEMA concentration demonstrated a 1.97-fold increased odds of dyslexia compared to those within the lowest quartile (95% confidence interval: 1.20-3.23). Thus, these findings suggested the possible link between HEMA levels and the risk of dyslexia. Further studies are warranted to validate this finding and illustrate the underlying mechanism.

Association between urinary propylene oxide metabolite and the risk of dyslexia.

Although it is a probable human carcinogen, propylene oxide is widely applied in industry and daily life. However, data on neurodevelopmental effects of propylene oxide exposure among children are extremely limited. We aimed to determine the urinary concentrations of propylene oxide metabolite among school-aged children and evaluate the potential association of propylene oxide exposure with risk of dyslexia. A total of 355 dyslexic children and 390 controls were recruited from three cities (Jining, Wuhan, and Hangzhou) in China, between 2017 and 2020. Urinary N-acetyl-S-(2-hydroxypropyl)-L-cysteine (i.e., 2-hydroxypropyl mercapturic acid; 2-HPMA) was measured as the biomarker of propylene oxide exposure. The detection frequency of 2-HPMA was 100%. After adjusting for potential confounders, the odds ratio (OR) for dyslexia per 2-fold increase in urinary 2-HPMA was 1.19 [95% confidence interval (95% CI): 1.01, 1.40, P = 0.042]. Compared with the lowest quartile of urinary 2-HPMA concentrations, children with the highest quartile of 2-HPMA had a 1.63-fold (95% CI: 1.03, 2.56, P = 0.036) significantly increased risk of dyslexia, with a dose-response relationship (P-trend = 0.047). This study provides epidemiological data on the potential association between propylene oxide exposure and the risk of dyslexia in children. Further studies are warranted to confirm the findings and reveal the underlying biological mechanisms.

The Prevalence of Thyroid Autoimmunity in Children with Developmental Dyslexia.

METHODS: We enrolled pediatric subjects with developmental dyslexia and, as a control group, healthy age- and sex-matched subjects without developmental dyslexia. Thyroid function was evaluated in subjects with developmental dyslexia measuring serum concentrations of thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4). Thyroid autoimmunity was evaluated in all subjects measuring antithyroid peroxidase (TPO-Ab) and antithyroglobulin (TG-Ab) antibodies. In subjects with developmental dyslexia, thyroid ultrasonography (US) was also performed. RESULTS: We enrolled 51 subjects with developmental dyslexia (M : F = 39 : 12, mean age 12.4 ± 9 years) and 34 controls (M : F = 24 : 10, mean age 10.8 ± 4 years). TPO-Ab positivity was significantly higher in subjects with developmental dyslexia compared to controls (60.8% vs. 2.9%, p < 0.001), while no significant difference was found in TG-Ab positivity (16% vs. 5.8%). Thyroid US performed in 49 subjects with developmental dyslexia revealed a thyroiditis pattern in 60%. CONCLUSIONS: We found an extremely high prevalence of thyroid autoimmunity in children with developmental dyslexia. Further studies are needed to confirm our observations, but our findings may change the approach to this disorder and eventually lead to a systematic determination of thyroid autoimmunity in children with developmental dyslexia.

Dyslexia in the 21st century.

PURPOSE OF REVIEW: Within the past decade tremendous advances have occurred in our understanding of dyslexia. RECENT FINDINGS: Reliable data now validate the definition of dyslexia as an unexpected difficulty in reading in an individual who has the ability to be a much better reader. That dyslexia is unexpected is now codified in US federal law (PL 115-391). Replicated studies using functional brain imaging have documented a neural signature for dyslexia. Epidemiologic, longitudinal data now demonstrate that dyslexia is highly prevalent, affecting 20% of the population, affecting boys and girls equally. These data further demonstrate that the achievement gap between dyslexic and typical readers is now evident as early as first grade and persists. Evidence-based, efficient, inexpensive screening tools now offer the possibility of universal screening to identify children at risk for dyslexia as early as first grade. Specialized schools which focus on dyslexic students provide welcoming communities, ensuring that dyslexic children will not only survive but thrive. SUMMARY: Taken together, these findings indicate that we must act and act now to ensure that this 21st century knowledge of dyslexia is disseminated to educators, policy makers, and most of all to parents of dyslexic children.

Characteristics of Students Identified With Dyslexia Within the Context of State Legislation.

All but seven U.S. states have laws that govern some aspects of dyslexia screening, intervention, or teacher training in public schools. However, in the three states that mandate child-level reporting, data indicate lower than expected rates of dyslexia identification when compared with commonly accepted dyslexia prevalence rates. To better understand this apparent mismatch, this study explores factors that might predict the school-assigned identification of individuals with dyslexia. Deidentified data on 7,947 second-grade students in 126 schools from one U.S. state included a universal screening measure of literacy skills indicative of dyslexia (i.e., reading and spelling), school-assigned dyslexia classification, and demographic characteristics. As expected, behavioral characteristics of dyslexia from universal screening were associated with school-assigned dyslexia classification. However, dyslexia classification was less likely for minority students and individuals attending schools with a higher percentage of minority students. Students who showed behavioral characteristics of dyslexia and attended schools with a higher proportion of other students with similar poor literacy skills were more likely not to receive a school-assigned dyslexia classification. The findings suggest systematic demographic differences in whether a student is identified with dyslexia by schools even when using universal screening.

Sluggish Cognitive Tempo: Sociodemographic, Behavioral, and Clinical Characteristics in a Population of Catalan School Children.

OBJECTIVE: The aims of the present study were to examine the presence of sluggish cognitive tempo (SCT) symptoms in children; associations of the symptoms with sociodemographic characteristics of the children; and relationships between SCT symptoms and symptoms of ADHD, dyslexia, academic performance, and behavioral problems. METHOD: We evaluated Catalan schoolchildren aged 7 to 10 years in Barcelona, 2012-2013. Parents filled out the SCT-Child Behavior Checklist (SCT-CBCL), the Strengths and Difficulties Questionnaire (SDQ), and a questionnaire concerning sociodemographic characteristics. Teachers completed the ADHD criteria of Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) (ADHD- DSM-IV), a list of dyslexia symptoms, and evaluated the children's academic performance. SCT symptoms were studied as a continuous and dichotomous variable. RESULTS: In all, 11% of the children in our sample scored above the clinical cut-off on the SCT-CBCL scale. We observed a higher rate of SCT symptoms in boys, children whose father was unemployed, those whose maternal educational level was lower, children with a high socioeconomic vulnerability index at home, those who reported maternal smoking during pregnancy and current second-hand smoke exposure at home, and children with an ADHD diagnosis. More SCT symptoms were associated with inattention symptoms, symptoms of dyslexia, academic problems, and emotional and peer relationship problems. CONCLUSION: We observed a higher prevalence of SCT symptoms in our sample than expected in the general population. While girls are less prone to SCT symptoms, some socioeconomic indicators, dyslexia, and inattention symptoms as well as exposure to smoking at home increase the risk of SCT and must be taken into account during assessments.

A screening on Specific Learning Disorders in an Italian speaking high genetic homogeneity area.

The aim of the present research is to investigate the prevalence of Specific Learning Disorders (SLD) in Ogliastra, an area of the island of Sardinia, Italy. Having experienced centuries of isolation, Ogliastra has become a high genetic homogeneity area, and is considered particularly interesting for studies on different kinds of pathologies. Here we are going to describe the results of a screening carried out throughout 2 consecutive years in 49 second grade classes (24 considered in the first year and 25 in the second year of the study) of the Ogliastra region. A total of 610 pupils (average age 7.54 years; 293 female, 317 male) corresponding to 68.69% of all pupils who were attending second grade in the area, took part in the study. The tool used for the screening was "RSR-DSA. Questionnaire for the detection of learning difficulties and disorders", which allowed the identification of 83 subjects at risk (13.61% of the whole sample involved in the study). These subjects took part in an enhancement training program of about 6 months. After the program, pupils underwent assessment for reading, writing and calculation abilities, as well as cognitive assessment. According to the results of the assessment, the prevalence of SLDs is 6.06%. For what concerns dyslexia, 4.75% of the total sample manifested this disorder either in isolation or in comorbidity with other disorders. According to the first national epidemiological investigation carried out in Italy, the prevalence of dyslexia is 3.1-3.2%, which is lower than the prevalence obtained in the present study. Given the genetic basis of SLDs, this result, together with the presence of several cases of SLD in isolation (17.14%) and with a 3:1 ratio of males to females diagnosed with a SLD, was to be expected in a sample coming from a high genetic homogeneity area.

[Validity assessment of a low level phonological processing test material in preschool children]. / Zur Validität eines Testmaterials zur basalen phonologischen Verarbeitung bei Vorschulkindern.

BACKGROUND: The BISC (Bielefelder Screening) is a German test to evaluate phonological skills believed to be a prerequisite for future reading and writing skills. BISC results may indicate an elevated risk for dyslexia. Our research group has put forward test material in order to specifically examine low-level phonological processing LLPP. In this study we analysed whether BISC and low-level phonological processing correlate. MATERIAL AND METHODS: A retrospective correlation analysis was carried out on primary school children's test results of the BISC and the newly developed low-level phonological processing test material. RESULTS: Spearman's rho was 0.52 between total LLPP and total BISC. The subscales correlated with a rho below 0.5. CONCLUSION: Results indicate that a low level phonological processing and higher level phonological processing can be differentiated. Future studies will have to clarify whether these results can be used to construct specifically targeting therapy strategies and whether the LLPP test material can be used to assess the risk of subsequent dyslexia also.

[Prediction of learning disability at school by means of SOPESS]. / Vorhersage von schulischen Lernstörungen durch SOPESS.

AIM OF THE STUDY: The responsibilities of public health authorities include early detection of risks for healthy development at school. Reading /writing disorder and math disorder are among the most common developmental disorders in childhood. METHOD: The present study conveys information about the prevalence of specific developmental disorders of scholastic skills (N=372) and assesses the prognostic validity of the social-paediatric screening of developmental status for school entry (SOPESS), the relevant criteria being DERET 1-2+, DEMAT 1+, and ELFE 1-6. RESULTS: The prevalence of specific developmental disorders of scholastic skills ranges from 1.1% for dyscalculia to 3.0% for dyslexia. Adequate correlations of r= -0.42(DERET 1-2+; DEMAT 1+) and r= -0.43 (ELFE 1-6) as well as substantial negative predictive values (0.80-0.93) suggest an acceptable screening performance. CONCLUSION: Children without clinical findings in SOPESS do not display any learning disabilities at onset of the 2nd grade while children marked at risk by SOPESS seem to benefit from concurrent intervention (e.g., language promotion programmes): such disabilities emerge in only half of these children.

[SOPESS results and medical recommendations for school beginners]. / Zusammenhang zwischen SOPESS-Ergebnissen und ärztlicher Befundbewertung.

AIM OF THE STUDY: The purpose of this study was to investigate the distribution of results of a developmental screening for school entry and procedures initiated by school doctors. METHOD: Based on achievement in SOPESS of 372 children (188 female, 184 male) and the resulting recommendations of the school doctors, the distribution of frequencies in cross-classified tables was analysed, and Cramer's V was calculated. RESULTS: No sex differences were found in early numeracy and coordination skills. Girls performed more frequently without any problems in the other domains assessed by SOPESS. Recommendations of school doctors referring to clarification of the finding or treatment are lower than the frequencies of critical results in SOPESS. This effect is especially critical in the domains of numeracy and attention. Critical SOPESS achievements in numeracy are found in 12% (attention: 10,2%) of the children, but only 0,5% (attention: 2,4%) are given recommendations for further treatment. An increase of documentation for parent counselling can be observed. CONCLUSION: Documentation of the findings shows that medical recommendations for most domains of SOPESS are in accordance with frequencies of critical screening results. Further information is necessary for the domains of attention and numeracy.

A longitudinal study of early reading difficulties and subsequent problem behaviors.

It is generally believed that early academic failure in school develops into a downward spiral of negative motivational and behavioral consequences. In this study, children with reading difficulties were compared with typical readers on questionnaires measuring ADHD symptoms and other behavior problems such as withdrawn symptoms, somatic complaints, anxiety/depression, social problems, and aggression. The results revealed that reading difficulties and problem behaviors appear more independent of each other rather than problem behaviors being a consequence of reading failure. In addition, gender differences were negligible when examining the relationship between reading difficulties and subsequent problem behavior. Some implications for special education and intervention are suggested.

Is season of birth related to developmental dyslexia?

Different moderators/mediators of risk are involved in developmental dyslexia (DD), but data are inconsistent. We explored the prevalence of season of birth and its association with gender and age of school entry in an Italian sample of dyslexic children compared to an Italian normal control group. The clinical sample included 498 children (345 boys, mean age 10.3 ± 2.1 years) with DD, the control sample 1,276 children (658 boys, mean age 10.8 ± 2.2 years) from four elementary schools from the same urban area, and with the same socio-economic status level. A prevalence of birth in autumn was found among children with DD compared to controls (34% versus 24%, p < 0.0001). Children with DD were more frequently males (p < 0.0001) and had a lower mean age of school entry (p < 0.0001). Regarding the distribution of ages, 11.4% of children with DD, but none of the subjects in the control group, started school before 5.7 years. Therefore, greater risk of DD was related to age of school entry (OR = 2.72), gender (OR = 2.16), and season of birth (OR = 1.21). Significant interactions between boys with DD born in autumn, and correct school of entry (OR = 2.56) were joint predictors of higher risk of DD. The association between birth in autumn and DD may be explained by the earlier age of school entry, which may be a critical element in the youngest children with DD or at risk to DD. Whether Italian school policy is oriented to anticipate the school entry, a closer detection of early learning disorders and associated risk factors (familial load, specific language disorders, and attention deficit hyperactivity disorder) should be warranted.

Problems and limitations in studies on screening for language delay.

This study discusses six common methodological limitations in screening for language delay (LD) as illustrated in 11 recent studies. The limitations are (1) whether the studies define a target population, (2) whether the recruitment procedure is unbiased, (3) attrition, (4) verification bias, (5) small sample size and (6) inconsistencies in choice of "gold standard". It is suggested that failures to specify a target population, high attrition (both at screening and in succeeding validation), small sample sizes and verification bias in validations are often caused by a misguided focus on screen positives (SPs). Other limitations are results of conflicting methodological goals. We identified three such conflicts. One consists of a dilemma between unbiased recruitment and attrition, another between the comprehensiveness of the applied gold standard and sample size in validation and the third between the specificity of the gold standard and the risk of not identifying co-morbid conditions.

[Is a specific disorder of arithmetic skills as common as reading/spelling disorder?]. / Sind Rechenstörungen genau so häufig wie Lese-Rechtschreibstörungen?

BACKGROUND: Referring to the prevalence rates of learning disorders in the research literature, the numbers of mathematics disorder and reading/spelling disorder are often reported to be identical. However, the correlation between intelligence level and reading/spelling skills is much weaker than between intelligence and arithmetic skills. If the same definition criterion is applied to both disorders, a lower prevalence rate for mathematics disorder should be expected. OBJECTIVE: Are there differences in the prevalence estimates for learning disorders depending on the definition criterion? METHOD: A large representative sample of German students (N=1970) was used to review the hypothesis. RESULTS: Depending on the definition criterion, we could show a prevalence range of mathematics disorder between 0.1% and 8.1% in the same sample. Using the same definition criterion for both learning disorders, there are two to three times as many students with reading/spelling disorder than those with mathematics disorder. DISCUSSION: Whenever children with reading/spelling disorder are compared to children with mathematics disorder, the same definition criterion has to be applied.

[Binocular status of dyslexics--are there differences to a healthy comparison group?]. / Binokularsehen bei Legasthenikern - Gibt es Unterschiede zu einer gesunden Vergleichsgruppe?

BACKGROUND: Despite numerous studies dealing with the question of a possible relation of visual problems and dyslexia, which is negated by most ophthalmologists, some opticians still favour the treatment of dyslexia by correction of the "Winkelfehlsichtigkeit" following MCH. Our aim was by also including the Pola test to check the usefulness of this treatment. PATIENTS AND METHODS: In a 2-year prospective study we examined the 4th grade elementary school students in our city who had dyslexia as an assured diagnosis (n = 21). The results were compared to those of an age-matched group without pathological findings regarding their reading and spelling ability (n = 21). Examinations included visual acuity, eye position by cover test, Maddox cylinder and Pola test for near distance, binocular vision (Bagolini and Worth test, Lang test I and II, Titmus test, amplitude of fusion), amplitude of accommodation, refraction in cycloplegia and organic status. RESULTS: A significant difference was found between the two groups regarding the amplitude of divergence in near (p = 0.009) and far distance (p = 0.019) which were both smaller for the dyslexia group, as well as the binocular near visual acuity (p = 0.04). Using the SAS procedure STEPDISC we discriminated the normal and dyslexia group by amplitude of divergence, near visual acuity and alternating near prism cover test with a sensitivity of 81 % and a specifity of 75 %. The results of the Pola test did not show any significant difference between the groups. CONCLUSIONS: No differences were found between the groups regarding the eye position. Therefore a treatment of dyslexia using prisms does not appear reasonable. However because of the group sizes the significance of the results is limited.

Persistence of literacy problems: spelling in adolescence and at mid-life.

BACKGROUND: Developmental reading problems show strong persistence across the school years; less is known about poor readers' later progress in literacy skills. METHOD: Poor (n = 42) and normally developing readers (n = 86) tested in adolescence (ages 14/15 years) in the Isle of Wight epidemiological studies were re-contacted at mid-life (ages 44/45 years). Participants completed a spelling test, and reported on educational qualifications, perceived adult spelling competence, and problems in day-to-day literacy tasks. RESULTS: Individual differences in spelling were highly persistent across this 30-year follow-up, with correlations between spelling at ages 14 and 44 years of r = .91 (p < .001) for poor readers and r = .89 (p < .001) for normally developing readers. Poor readers' spelling remained markedly impaired at mid-life, with some evidence that they had fallen further behind over the follow-up period. Taking account of adolescent spelling levels, continued exposure to reading and literacy demands in adolescence and early adulthood was independently predictive of adult spelling in both samples; family social background added further to prediction among normally developing readers only. CONCLUSIONS: By adolescence, individual differences in spelling and its related sub-skills are highly stable. Encouraging young people with reading disabilities to maintain their exposure to reading and writing may be advantageous in the longer term.

Floor effects associated with universal screening and their impact on the early identification of reading disabilities.

Response to intervention (RTI) holds great promise for the early identification and prevention of reading disabilities. The success of RTI rests in part on the accuracy of universal screening tools used within this framework. Despite advancements, screening instruments designed to identify children at risk for reading disabilities continue to have limited predictive validity. In this study, the authors examined a common screening instrument for the presence of floor effects and investigated the impact that these effects have on the predictive validity of the instrument. Longitudinal data (kindergarten to third grade) from a large cohort of children were used. These data included children's performance on five measures from the Dynamic Indicators of Basic Early Literacy Skills (DIBELS) and two reading achievement outcome measures. The results showed that DIBELS measures were characterized by floor effects in their initial administrations and that these effects reduced the predictive validity of the measures. The implications of these findings for early identification are discussed.

Developmental links of very early phonological and language skills to second grade reading outcomes: strong to accuracy but only minor to fluency.

The authors examined second grade reading accuracy and fluency and their associations via letter knowledge to phonological and language predictors assessed at 3.5, 4.5, and 5.5 years in children in the Jyväskylä Longitudinal Study of Dyslexia. Structural equation modeling showed that a developmentally highly stable factor (early phonological and language processing [EPLP]) behind key dyslexia predictors (i.e., phonological awareness, short-term memory, rapid naming, vocabulary, and pseudoword repetition) could already be identified at 3.5 years. EPLP was significantly associated with reading and spelling accuracy and by age with letter knowledge. However, EPLP had only a minor link with reading fluency, which was additionally explained by early letter knowledge. The results show that reading accuracy is well predicted by early phonological and language skills. Variation in fluent reading skills is not well explained by early skills, suggesting factors other than phonological core skills. Future research is suggested to explore the factors behind the development of fast and accurate decoding skills.

An examination of lexical and sublexical reading skills in children with neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) is an inherited neurocutaneous disorder associated with a high frequency of cognitive and learning difficulties. Based on discrepancies between IQ and academic achievement, approximately 17% of children with NF1 have been classified as having reading impairments. In this study, the lexical and sublexical reading skills of children with NF1 (n = 30) were examined using the Castles' Word/Non-Word Test (modified version), together with measures of neuropsychological functioning and academic achievement. Twenty children (67%) demonstrated deficits in one or more reading subskills, with 75% of these meeting criteria for phonological dyslexia and 20% classified with mixed dyslexia. These findings indicate that a large proportion of children with NF1 may be characterized by a specific difficulty with the sublexical procedure, suggesting a difficulty employing spelling-to-sound rules to assemble a pronunciation when reading. In line with previous studies, the present findings also suggest that discrepancy-based methods may not be sufficiently sensitive to identify children who experience reading difficulties.

Cooccurrence of problems in activity level, attention, psychosocial adjustment, reading and writing in children with developmental coordination disorder.

The purpose of this paper was to investigate the cooccurrence of problems in activity level, attention, reading, writing and psychosocial adjustment of children with developmental coordination disorder (DCD). A parent-report questionnaire, the Developmental Coordination Disorder Questionnaire - Chinese version (DCDQ-C), was used to screen first to third graders from 13 mainstream schools in Taipei. Two standardized motor tests were then administered to those who scored below 10% on the DCDQ-C. Tests of activity level, attention, reading, writing and psychosocial adjustment were then administered to this sample. Thirty-eight children identified as DCD, 32 as suspect for DCD and 82 as normal comparison were included in the final sample. Multivariate analysis of variance comparing the three groups (DCD, suspect DCD, and comparison) revealed that both children with DCD and suspect for DCD obtained significantly poorer scores on measures of attention and reading, and were more hyperactive than comparison children. Children with DCD and suspect for DCD were also reported to have more internalizing and social problems than children without motor problems. No significant differences, however, were noted between children with different degree of motor coordination problems (categorized as DCD and suspect for DCD) on any measure. Furthermore, a high percentage of children in both the DCD and suspect groups fell in the clinical range of attention, activity level and psychosocial adjustment problems. The results revealed a high risk for these problems in nonreferred children with motor coordination problems. The high percentage of clinical range behavioral problems warrants attention of clinicians who work with children with motor coordination difficulties to the need to promote early identification and referral.