Procedural differences in the calculation of the prevalence of reading difficulties in Spanish-speaking school children / Diferencias procedimentales en el cálculo de la prevalencia del retraso lector en escolares hispanoparlantes

Prevalence of developmental dyslexia among primary school children in Arab countries: a systematic review and meta-analysis

BACKGROUND

Dyslexia is one of the most common learning disabilities. It poses challenges in reading skills development and can have a lasting impact in other areas of learning.

AIMS

To investigate the prevalence of developmental dyslexia among primary school children aged 6-13 in Arab countries, and to explore associations with gender and residency.

METHOD

Following the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines, we included studies up to December 2023 that were found in English and Arabic research database searches. Random-effects proportional meta-analyses determined the prevalence of dyslexia in Arab countries, with a direct comparison between girls and boys using odds ratios.

RESULTS

The meta-analysis included 18 studies with 30,243 participants: eight studies (44 %) from Egypt, four (22 %) from Saudi Arabia, and six (34 %) from other Arab countries. The pooled prevalence of dyslexia for children aged 6-13 in these studies was 11 %. The odds ratio for girls vs. boys was 0.85 (95 %). Geographical variations were notable, with eight studies (44 %) from Asia and ten (56 %) from Africa. Eight studies (44 %) were from the Gulf region, while ten (56 %) were from non-Gulf region. Prevalence of dyslexia was significantly higher in Arab countries in Asia (24 %) than in Africa (12 %), and the prevalence in non-Gulf countries was 13 % which was nearly half in comparison to Gulf countries (24 %).

CONCLUSIONS

The prevalence rates of dyslexia in primary school children varies across the Arab world, with higher rates among boys, Arab countries in Asia, and Gulf countries. Further research is needed to include both genders and standardized diagnostics across more Arab countries to understand and address dyslexia effectively.

Prevalence of developmental dyslexia in primary school children: a protocol for systematic review and meta-analysis

BACKGROUND

Developmental dyslexia (DD) is a specific impairment during the acquisition of reading skills and may have a lifelong negative impact on individuals. Reliable estimates of the prevalence of DD serve as the basis for evidence-based health resource allocation and policy making. However, the prevalence of DD in primary school children varies largely across studies. Moreover, it is unclear whether there are differences in prevalence in different genders and writing systems. Hence, the present study aims to conduct a systematic review and meta-analysis to assess the global prevalence of DD and to explore related factors.

METHODS

We will undertake a comprehensive literature search in 14 databases, including EMBASE, PubMed, Web of Science, China National Knowledge Infrastructure and Cochrane, from their inception to June 2021. Cross-sectional and longitudinal studies that describe the prevalence of DD will be eligible. The quality of the included observational studies will be assessed using the Strengthening the Reporting of Observational Studies in Epidemiology statement. The risk of bias will be determined by sensitivity analysis to identify publication bias.

RESULTS

One meta-analysis will be conducted to estimate the prevalence of DD in primary school children. Heterogeneity will be assessed in terms of the properties of subjects (e.g., gender, grade and writing system) and method of diagnosis in the included primary studies. Subgroup analyses will also be performed for population and secondary outcomes.

CONCLUSION

The results will synthesize the prevalence of DD and provide information for policy-makers and public health specialists.

Neurodevelopmental disorders among Spanish school-age children: prevalence and sociodemographic correlates

BACKGROUND

Prevalence estimates of neurodevelopmental disorders (ND) are essential for treatment planning. However, epidemiological research has yielded highly variable rates across countries, including Spain. This study examined the prevalence and sociodemographic correlates of ND in a school sample of Spanish children and adolescents.

METHODS

The Child Behaviour Checklist/Teacher's Report Form/Youth Self-Report and the Conners' Rating Scales were administered for screening purposes. Additionally, teachers provided information on reading and writing difficulties. Subjects who screened positive were interviewed for diagnostic confirmation according to the Diagnostic and Statistical Manual of Mental Disorders criteria. The final population comprised 6834 students aged 5-17. Multivariate analyses were performed to determine the influence of gender, age, educational stage, school type, socioeconomic status (SES), and ethnicity on the prevalence estimates.

RESULTS

A total of 1249 (18.3%) subjects met criteria for at least one ND, although only 423 had already received a diagnosis. Specifically, the following prevalence rates were found: intellectual disabilities (ID), 0.63%; communication disorders, 1.05%; autism spectrum disorder (ASD), 0.70%; attention-deficit/hyperactivity disorder (ADHD), 9.92%; specific learning disorder (SLD), 10.0%; and motor disorders, 0.76%. Students of foreign origin and from low SES evidenced higher odds of having ID. Boys were more likely to display ASD or a motor disorder. Age, SES, and ethnicity were significant predictors for SLD, while communication disorders and ADHD were also associated with gender.

CONCLUSIONS

The prevalence of ND among Spanish students is consistent with international studies. However, a substantial proportion had never been previously diagnosed, which emphasise the need for early detection and intervention programmes.

Prevalence of Developmental Dyslexia in Primary School Children: A Systematic Review and Meta-Analysis

Background: Developmental dyslexia (DD) is a specific learning disorder concerning reading acquisition that may has a lifelong negative impact on individuals. A reliable estimate of the prevalence of DD serves as the basis for diagnosis, intervention, and evidence-based health resource allocation and policy-making. Hence, the present meta-analysis aims to generate a reliable prevalence estimate of DD worldwide in primary school children and explore the potential variables related to that prevalence. Methods: Studies from the 1950s to June 2021 were collated using a combination of search terms related to DD and prevalence. Study quality was assessed using the STROBE guidelines according to the study design, with study heterogeneity assessed using the I2 statistic, and random-effects meta-analyses were conducted. Variations in the prevalence of DD in different subgroups were assessed via subgroup meta-analysis and meta-regression. Results: The pooled prevalence of DD was 7.10% (95% CI: 6.27–7.97%). The prevalence in boys was significantly higher than that in girls (boys: 9.22%, 95%CI, 8.07–10.44%; girls: 4.66%, 95% CI, 3.84–5.54%; p < 0.001), but no significant difference was found in the prevalence across different writing systems (alphabetic scripts: 7.26%, 95%CI, 5.94–8.71%; logographic scripts: 6.97%, 95%CI, 5.86–8.16%; p > 0.05) or across different orthographic depths (shallow: 7.13%, 95% CI, 5.23–9.30%; deep: 7.55%, 95% CI, 4.66–11.04%; p > 0.05). It is worth noting that most articles had small sample sizes with diverse operational definitions, making comparisons challenging. Conclusions: This study provides an estimation of worldwide DD prevalence in primary school children. The prevalence was higher in boys than in girls but was not significantly different across different writing systems.