Prevalence of Developmental Dyslexia among Primary School Children in Iran: A Systematic Review and Meta-Analysis
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Abstract
Objective: Developmental dyslexia is a specific learning disability related to reading that often leads to lifelong challenges. Accurate prevalence estimates are essential for the timely diagnosis, intervention, and formulation of appropriate educational policies. This systematic review and meta-analysis aimed to provide a reliable estimate of the prevalence of developmental dyslexia in primary school students in Iran.
Method: We conducted a comprehensive search of international databases, including PubMed, Web of Science, and Scopus, alongside national databases such as SID and Magiran, using relevant search terms from 1991 to April 2024. Two researchers independently assessed the articles for the risk of bias using the Hoy checklist and extracted the data. Subgroup meta-analysis examined variations in prevalence across different subgroups.
Results: A total of 18 studies, comprising 28,952 participants, were included. The overall prevalence of developmental dyslexia was 5.7% (95% CI: 4.5%-6.9%), with a higher prevalence observed in boys (7.5%, 95% CI: 5.8%-9.2%) compared to girls (4%, 95% CI: 3%-5%). Subgroup analysis revealed a statistically significant impact of diagnostic material on prevalence estimates, with informal reading tests reporting a prevalence of 3.4% (95% CI: 2.4%-4.4%) and the screening inventory reading test showing 8.8% (95% CI: 4.5%-13.2%) (P = 0.002). Prevalence also varied by sample size, with smaller studies (< 500 participants) reporting a prevalence of 6.8% (95% CI: 5%-8.6%) compared to larger studies (>2000 participants) at 3.9% (95% CI: 2.3%-5.4%) (P = 0.034). Most studies (66.7%) had sample sizes under 2000 participants.
Conclusion: This systematic review and meta-analysis indicate that developmental dyslexia affects 5.7% of Iranian primary school students, with boys being more affected than girls. These findings highlight the urgent need for standardized diagnostic criteria and evidence-based interventions to enhance early identification and support for students with dyslexia. Addressing these gaps is essential for improving educational outcomes and guiding effective policy planning.
1. Grigorenko EL. Developmental dyslexia: an update on genes, brains, and environments. J Child Psychol Psychiatry. 2001;42(1):91-125.
2. Lyon GR, Shaywitz SE, Shaywitz BA. A definition of dyslexia. Ann Dyslexia. 2003;53:1-14.
3. Association AP. Neurodevelopmental disorders: DSM-5® selections: American Psychiatric Pub; 2015.
4. Peterson RL, Pennington BF. Developmental dyslexia. Annu Rev Clin Psychol. 2015;11:283-307.
5. Katz L. The reading process is different for different orthographies: The orthographic depth hypothesis. InR. Frost & L. Katz (Eds.), Orthography, phonology, morphology, and meaning (pp. 67–84). Amsterdam: Elsevier Science Publishers. 1992;10:S0166-4115.
6. Caravolas M, Lervåg A, Defior S, Seidlová Málková G, Hulme C. Different patterns, but equivalent predictors, of growth in reading in consistent and inconsistent orthographies. Psychol Sci. 2013;24(8):1398-407.
7. Caravolas M, Lervåg A, Mousikou P, Efrim C, Litavsky M, Onochie-Quintanilla E, et al. Common patterns of prediction of literacy development in different alphabetic orthographies. Psychol Sci. 2012;23(6):678-86.
8. Furnes B, Samuelsson S. Preschool cognitive and language skills predicting Kindergarten and Grade 1 reading and spelling: a cross‐linguistic comparison. J Res Read. 2009;32(3):275-92.
9. Ziegler JC, Goswami U. Reading acquisition, developmental dyslexia, and skilled reading across languages: a psycholinguistic grain size theory. Psychol Bull. 2005;131(1):3-29.
10. Landerl K, Ramus F, Moll K, Lyytinen H, Leppänen PH, Lohvansuu K, et al. Predictors of developmental dyslexia in European orthographies with varying complexity. J Child Psychol Psychiatry. 2013;54(6):686-94.
11. Seymour PH, Aro M, Erskine JM. Foundation literacy acquisition in European orthographies. Br J Psychol. 2003;94(Pt 2):143-74.
12. QasemiZadeh B, Rahimi S, Namnabat M, Koochari A, editors. Farsi morphology. 11th Computer Society of Iran Computer Conference, IPM, Tehran, Iran; 2006.
13. Bijankhan M, Alaee Abouzar E. Orthographic depth of Persian. Language Research. 2013;4(1):1-19.
14. Aldakhil AF. Prevalence of developmental dyslexia among primary school children in Arab countries: a systematic review and meta-analysis. Res Dev Disabil. 2024;152:104812.
15. Hakim A, Ghorbanibirgani A. Prevalence of Dyslexia among Male Students in Primary Schools and Its Relationship with Obesity and Being Overweight in Ahvaz, Iran. Int J Community Based Nurs Midwifery. 2015;3(2):116-22.
16. Echreshavi M, Khalatbari J, Hosseinpour R. Investigating the prevalence of dyslexia and its characteristics in elementary school students. Middle Eastern Journal of Disability Studies. 2020;10:238-.
17. Mohammadyfar MA, Besharat MA, Ghasemi M, Najaphy M. The study of the prevalence rate and diversity of specific learning disabilities in students of primary school of Shiraz city. Educational Psychology. 2007;3(9):22-46.
18. Sedaghati L, Foroughi R, Shafiei B, Maracy MR. Prevalence of dyslexia in first to fifth grade elementary students Isfahan, Iran. Audiology. 2010;19(1):94-101.
19. Pashapour N, Yavarian R. Study of dyslexia incidence in Urmia elementary schools. Research in Medicine. 2000;24(1):3-6.
20. Yavari A, Valizadeh A, Maroufizadeh S, Panahian M. The prevalence of dyslexia among school age Persian speaking students in Arak, Iran.
21. Shahbodaghi MR. Investigating the prevalence of speech and language disorders among female primary school students. Quarterly Rehabilitation Archive 2003;3(4):20-6. Available from: https://rehabilitationj.uswr.ac.ir/article-1-579-fa.html.
22. Gholamiyan Arefi M, Safaeyan S, Ghaemi H, Balouchian G, Dabirian M, Rezaei M, et al. Speech and Reading Disorders Screening, and Problems in Structure and Function of Articulation Organs in Children in Mashhad City, Iran. Iranian Rehabilitation Journal. 2022;20(3):415-24.
23. Bavazin F, Posht Yafteh A. Investigating the prevalence of reading disorders in the second and third grades of elementary school in Khorram Abad city. Proceedings of the First Conference on Psychology, Counseling and Behavioral Science; 2019 Jun 13; Tehran, Iran; 2019. Available from: https://civilica.com/doc/913098/
24. Hosseini Izadi SMM, Ashuri Sheikhi M, Riahi Z, Khadivi E. Prevalence percentage of dyslexia in elementary age. Proceedings of the second international conference and the third national conference on new findings in management, psychology and accounting. 2023 Jul 22; Tehran, Iran; 2023. Available from: https://civilica.com/doc/1745879/
25. Pouretemad HR, Khatibi A, Zarei M, Stein J. Manifestations of developmental dyslexia in monolingual Persian speaking students. Arch Iran Med. 2011;14(4):259-65.
26. Sharifi AA, Davari R. Prevalence of learning disabilities in first and second grade students of elementary school in Chaharmahal Va bakhtiari Province. Journal of Learning Disabilities. 2012;1(2):63-76.
27. Zare Bahramabadi M, Ganji K. The study of prevalence of attention deficit/hyperactivity disorder (ADHD) and it’s comorbidity with learning disorder (LD) in primary school’s students. Journal of Learning Disabilities. 2014;3(4):25-43.
28. Gholami Kerahroodi S, ghorbani k. Investigating the prevalence of reading and writing disorders in the third grade students of Arak city. Proceeding of the International conference on humanities, psychology and social sciences. 2015 17 Nov; Tehran, Iran; 2016. Available from: https://civilica.com/doc/436459/
29. RAHIMIAN BE, Sadeghi A. Prevalence of reading disorder in primary school students. 2007.
30. Arab Ameri M, Hamzeian A, Ali Rad S. Investigating the prevalence of learning disorders in students of the second to fifth grades of elementary schools and the level of knowledge of teachers in Semnan province. Proceedings of the International Conference on Management and Humanities. 2015 Nov 29; UAE-Dubai; 2016. Available from: https://civilica.com/doc/425347/
31. Wagner RK, Zirps FA, Wood SG. Developmental dyslexia. The science of reading: A handbook. 2022:416-38.
32. Wagner RK, Zirps FA, Edwards AA, Wood SG, Joyner RE, Becker BJ, et al. The prevalence of dyslexia: A new approach to its estimation. J Learn Disabil. 2020;53(5):354-65.
33. Zou L, Huang A, Wu K, Zhang X, Zhang K, Wen W, et al. Home reading environment, sociometric and demographic factors associated with dyslexia in primary school students in China: A case-control study. Heliyon. 2023;9(11):e22100.
34. Chan DW, Ho CSh, Tsang Sm, Lee Sh, Chung KK. Prevalence, gender ratio and gender differences in reading‐related cognitive abilities among Chinese children with dyslexia in Hong Kong. Educational Studies. 2007;33(2):249-65.
35. Arnett AB, Pennington BF, Peterson RL, Willcutt EG, DeFries JC, Olson RK. Explaining the sex difference in dyslexia. J Child Psychol Psychiatry. 2017;58(6):719-27.
36. Miciak J, Fletcher JM. The Critical Role of Instructional Response for Identifying Dyslexia and Other Learning Disabilities. J Learn Disabil. 2020;53(5):343-53.
37. Vaughn S, Miciak J, Clemens N, Fletcher JM. The critical role of instructional response in defining and identifying students with dyslexia: a case for updating existing definitions. Ann Dyslexia. 2024;74(3):325-36.
38. Hoy D, Brooks P, Woolf A, Blyth F, March L, Bain C, et al. Assessing risk of bias in prevalence studies: modification of an existing tool and evidence of interrater agreement. J Clin Epidemiol. 2012;65(9):934-9.
39. Higgins JP. Cochrane handbook for systematic reviews of interventions version 5.0. 1. The Cochrane Collaboration. http://www cochrane-handbook org. 2008.
40. Greenland S, Lash TL. Modern epidemiology: Lippincott Williams & Wilkins; 2008.
41. Higgins JP, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta-analyses. Bmj. 2003;327(7414):557-60.
42. Shi L, Lin L. The trim-and-fill method for publication bias: practical guidelines and recommendations based on a large database of meta-analyses. Medicine (Baltimore). 2019;98(23):e15987.
43. Azizian M, Abedi M. Construction and standardization of reading level diagnostic test for third grade primary school children. Iranian Journal of Psychiatry and Clinical Psychology. 2006;11(4):379-87.
44. Shafiei B, Tavakol S, Alinia L, Maracy MR, Sedaghati L, Foroughi R. Developing a screening inventory reading test (IRT) for the Isfahanian students of the first to fifth grade. Audiology. 2009;17(2):53-60.
45. Lin Y, Zhang X, Huang Q, Lv L, Huang A, Li A, et al. The Prevalence of Dyslexia in Primary School Children and Their Chinese Literacy Assessment in Shantou, China. Int J Environ Res Public Health. 2020;17(19):7140.
46. Al-Qadri AH, Zhao W, Li M, Al-Khresheh MH, Boudouaia A. The prevalence of the academic learning difficulties: An observation tool. Heliyon. 2021;7(10):e08164.
47. Pashapour N, Yavarian R. Study of dyslexia incidence in Urmia elementary schools. Research in Medicine. 2000;24(1):3-6.
48. Shaghaghi M. Prevalence rate of learning disorders among second and third grade students of Khorramdare city. Proceedings of the National conference of primary education. 2015 Dec; Birjand, Iran; 2015. Available from: https://www.sid.ir/paper/858451/fa
49. Di Folco C, Guez A, Peyre H, Ramus F. Epidemiology of reading disability: A comparison of DSM-5 and ICD-11 criteria. Scientific Studies of Reading. 2022;26(4):337-55.
50. Granocchio E, De Salvatore M, Bonanomi E, Sarti D. Sex-related differences in reading achievement. J Neurosci Res. 2023;101(5):668-78.
51. Glica A, Wasilewska K, Kossowski B, Żygierewicz J, Jednoróg K. Sex Differences in Low-Level Multisensory Integration in Developmental Dyslexia. J Neurosci. 2024;44(3):e0944232023.
52. Evans TM, Flowers DL, Napoliello EM, Eden GF. Sex-specific gray matter volume differences in females with developmental dyslexia. Brain Struct Funct. 2014;219(3):1041-54.
53. Chyl K, Kossowski B, Dębska A, Łuniewska M, Marchewka A, Pugh KR, et al. Reading Acquisition in Children: Developmental Processes and Dyslexia-Specific Effects. J Am Acad Child Adolesc Psychiatry. 2019;58(10):948-60.
54. Yang L, Li C, Li X, Zhai M, An Q, Zhang Y, et al. Prevalence of Developmental Dyslexia in Primary School Children: A Systematic Review and Meta-Analysis. Brain Sci. 2022;12(2):240.
55. Zhao H, Zhang B, Chen Y, Zhou X, Zuo P. Environmental Risk Factors in Han and Uyghur Children with Dyslexia: A Comparative Study. PLoS One. 2016;11(7):e0159042.
56. El Sheikh MM, El Missiry MA, Hatata HA, Sabry WM, El Fiky AAA, Essawi HI. Frequency of occurrence of specific reading disorder and associated psychiatric comorbidity in a sample of Egyptian primary school students. Child Adolesc Ment Health. 2016;21(4):209-16.
57. Migliavaca CB, Stein C, Colpani V, Barker TH, Ziegelmann PK, Munn Z, et al. Meta-analysis of prevalence: I(2) statistic and how to deal with heterogeneity. Res Synth Methods. 2022;13(3):363-7.
58. Sharifi AA, Davari R. prevalence of reading disorder a among primary school students in Shahrekord. Journal of Exceptional Children. 2009;8(4):413-8.
59. Hosseinaee A, Aghajani A, Nofresti A. Prevalence of reading and writing disabilities among primary school students. Developmental Psychology: Journal of Iranian Psychologists. 2011.
2. Lyon GR, Shaywitz SE, Shaywitz BA. A definition of dyslexia. Ann Dyslexia. 2003;53:1-14.
3. Association AP. Neurodevelopmental disorders: DSM-5® selections: American Psychiatric Pub; 2015.
4. Peterson RL, Pennington BF. Developmental dyslexia. Annu Rev Clin Psychol. 2015;11:283-307.
5. Katz L. The reading process is different for different orthographies: The orthographic depth hypothesis. InR. Frost & L. Katz (Eds.), Orthography, phonology, morphology, and meaning (pp. 67–84). Amsterdam: Elsevier Science Publishers. 1992;10:S0166-4115.
6. Caravolas M, Lervåg A, Defior S, Seidlová Málková G, Hulme C. Different patterns, but equivalent predictors, of growth in reading in consistent and inconsistent orthographies. Psychol Sci. 2013;24(8):1398-407.
7. Caravolas M, Lervåg A, Mousikou P, Efrim C, Litavsky M, Onochie-Quintanilla E, et al. Common patterns of prediction of literacy development in different alphabetic orthographies. Psychol Sci. 2012;23(6):678-86.
8. Furnes B, Samuelsson S. Preschool cognitive and language skills predicting Kindergarten and Grade 1 reading and spelling: a cross‐linguistic comparison. J Res Read. 2009;32(3):275-92.
9. Ziegler JC, Goswami U. Reading acquisition, developmental dyslexia, and skilled reading across languages: a psycholinguistic grain size theory. Psychol Bull. 2005;131(1):3-29.
10. Landerl K, Ramus F, Moll K, Lyytinen H, Leppänen PH, Lohvansuu K, et al. Predictors of developmental dyslexia in European orthographies with varying complexity. J Child Psychol Psychiatry. 2013;54(6):686-94.
11. Seymour PH, Aro M, Erskine JM. Foundation literacy acquisition in European orthographies. Br J Psychol. 2003;94(Pt 2):143-74.
12. QasemiZadeh B, Rahimi S, Namnabat M, Koochari A, editors. Farsi morphology. 11th Computer Society of Iran Computer Conference, IPM, Tehran, Iran; 2006.
13. Bijankhan M, Alaee Abouzar E. Orthographic depth of Persian. Language Research. 2013;4(1):1-19.
14. Aldakhil AF. Prevalence of developmental dyslexia among primary school children in Arab countries: a systematic review and meta-analysis. Res Dev Disabil. 2024;152:104812.
15. Hakim A, Ghorbanibirgani A. Prevalence of Dyslexia among Male Students in Primary Schools and Its Relationship with Obesity and Being Overweight in Ahvaz, Iran. Int J Community Based Nurs Midwifery. 2015;3(2):116-22.
16. Echreshavi M, Khalatbari J, Hosseinpour R. Investigating the prevalence of dyslexia and its characteristics in elementary school students. Middle Eastern Journal of Disability Studies. 2020;10:238-.
17. Mohammadyfar MA, Besharat MA, Ghasemi M, Najaphy M. The study of the prevalence rate and diversity of specific learning disabilities in students of primary school of Shiraz city. Educational Psychology. 2007;3(9):22-46.
18. Sedaghati L, Foroughi R, Shafiei B, Maracy MR. Prevalence of dyslexia in first to fifth grade elementary students Isfahan, Iran. Audiology. 2010;19(1):94-101.
19. Pashapour N, Yavarian R. Study of dyslexia incidence in Urmia elementary schools. Research in Medicine. 2000;24(1):3-6.
20. Yavari A, Valizadeh A, Maroufizadeh S, Panahian M. The prevalence of dyslexia among school age Persian speaking students in Arak, Iran.
21. Shahbodaghi MR. Investigating the prevalence of speech and language disorders among female primary school students. Quarterly Rehabilitation Archive 2003;3(4):20-6. Available from: https://rehabilitationj.uswr.ac.ir/article-1-579-fa.html.
22. Gholamiyan Arefi M, Safaeyan S, Ghaemi H, Balouchian G, Dabirian M, Rezaei M, et al. Speech and Reading Disorders Screening, and Problems in Structure and Function of Articulation Organs in Children in Mashhad City, Iran. Iranian Rehabilitation Journal. 2022;20(3):415-24.
23. Bavazin F, Posht Yafteh A. Investigating the prevalence of reading disorders in the second and third grades of elementary school in Khorram Abad city. Proceedings of the First Conference on Psychology, Counseling and Behavioral Science; 2019 Jun 13; Tehran, Iran; 2019. Available from: https://civilica.com/doc/913098/
24. Hosseini Izadi SMM, Ashuri Sheikhi M, Riahi Z, Khadivi E. Prevalence percentage of dyslexia in elementary age. Proceedings of the second international conference and the third national conference on new findings in management, psychology and accounting. 2023 Jul 22; Tehran, Iran; 2023. Available from: https://civilica.com/doc/1745879/
25. Pouretemad HR, Khatibi A, Zarei M, Stein J. Manifestations of developmental dyslexia in monolingual Persian speaking students. Arch Iran Med. 2011;14(4):259-65.
26. Sharifi AA, Davari R. Prevalence of learning disabilities in first and second grade students of elementary school in Chaharmahal Va bakhtiari Province. Journal of Learning Disabilities. 2012;1(2):63-76.
27. Zare Bahramabadi M, Ganji K. The study of prevalence of attention deficit/hyperactivity disorder (ADHD) and it’s comorbidity with learning disorder (LD) in primary school’s students. Journal of Learning Disabilities. 2014;3(4):25-43.
28. Gholami Kerahroodi S, ghorbani k. Investigating the prevalence of reading and writing disorders in the third grade students of Arak city. Proceeding of the International conference on humanities, psychology and social sciences. 2015 17 Nov; Tehran, Iran; 2016. Available from: https://civilica.com/doc/436459/
29. RAHIMIAN BE, Sadeghi A. Prevalence of reading disorder in primary school students. 2007.
30. Arab Ameri M, Hamzeian A, Ali Rad S. Investigating the prevalence of learning disorders in students of the second to fifth grades of elementary schools and the level of knowledge of teachers in Semnan province. Proceedings of the International Conference on Management and Humanities. 2015 Nov 29; UAE-Dubai; 2016. Available from: https://civilica.com/doc/425347/
31. Wagner RK, Zirps FA, Wood SG. Developmental dyslexia. The science of reading: A handbook. 2022:416-38.
32. Wagner RK, Zirps FA, Edwards AA, Wood SG, Joyner RE, Becker BJ, et al. The prevalence of dyslexia: A new approach to its estimation. J Learn Disabil. 2020;53(5):354-65.
33. Zou L, Huang A, Wu K, Zhang X, Zhang K, Wen W, et al. Home reading environment, sociometric and demographic factors associated with dyslexia in primary school students in China: A case-control study. Heliyon. 2023;9(11):e22100.
34. Chan DW, Ho CSh, Tsang Sm, Lee Sh, Chung KK. Prevalence, gender ratio and gender differences in reading‐related cognitive abilities among Chinese children with dyslexia in Hong Kong. Educational Studies. 2007;33(2):249-65.
35. Arnett AB, Pennington BF, Peterson RL, Willcutt EG, DeFries JC, Olson RK. Explaining the sex difference in dyslexia. J Child Psychol Psychiatry. 2017;58(6):719-27.
36. Miciak J, Fletcher JM. The Critical Role of Instructional Response for Identifying Dyslexia and Other Learning Disabilities. J Learn Disabil. 2020;53(5):343-53.
37. Vaughn S, Miciak J, Clemens N, Fletcher JM. The critical role of instructional response in defining and identifying students with dyslexia: a case for updating existing definitions. Ann Dyslexia. 2024;74(3):325-36.
38. Hoy D, Brooks P, Woolf A, Blyth F, March L, Bain C, et al. Assessing risk of bias in prevalence studies: modification of an existing tool and evidence of interrater agreement. J Clin Epidemiol. 2012;65(9):934-9.
39. Higgins JP. Cochrane handbook for systematic reviews of interventions version 5.0. 1. The Cochrane Collaboration. http://www cochrane-handbook org. 2008.
40. Greenland S, Lash TL. Modern epidemiology: Lippincott Williams & Wilkins; 2008.
41. Higgins JP, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta-analyses. Bmj. 2003;327(7414):557-60.
42. Shi L, Lin L. The trim-and-fill method for publication bias: practical guidelines and recommendations based on a large database of meta-analyses. Medicine (Baltimore). 2019;98(23):e15987.
43. Azizian M, Abedi M. Construction and standardization of reading level diagnostic test for third grade primary school children. Iranian Journal of Psychiatry and Clinical Psychology. 2006;11(4):379-87.
44. Shafiei B, Tavakol S, Alinia L, Maracy MR, Sedaghati L, Foroughi R. Developing a screening inventory reading test (IRT) for the Isfahanian students of the first to fifth grade. Audiology. 2009;17(2):53-60.
45. Lin Y, Zhang X, Huang Q, Lv L, Huang A, Li A, et al. The Prevalence of Dyslexia in Primary School Children and Their Chinese Literacy Assessment in Shantou, China. Int J Environ Res Public Health. 2020;17(19):7140.
46. Al-Qadri AH, Zhao W, Li M, Al-Khresheh MH, Boudouaia A. The prevalence of the academic learning difficulties: An observation tool. Heliyon. 2021;7(10):e08164.
47. Pashapour N, Yavarian R. Study of dyslexia incidence in Urmia elementary schools. Research in Medicine. 2000;24(1):3-6.
48. Shaghaghi M. Prevalence rate of learning disorders among second and third grade students of Khorramdare city. Proceedings of the National conference of primary education. 2015 Dec; Birjand, Iran; 2015. Available from: https://www.sid.ir/paper/858451/fa
49. Di Folco C, Guez A, Peyre H, Ramus F. Epidemiology of reading disability: A comparison of DSM-5 and ICD-11 criteria. Scientific Studies of Reading. 2022;26(4):337-55.
50. Granocchio E, De Salvatore M, Bonanomi E, Sarti D. Sex-related differences in reading achievement. J Neurosci Res. 2023;101(5):668-78.
51. Glica A, Wasilewska K, Kossowski B, Żygierewicz J, Jednoróg K. Sex Differences in Low-Level Multisensory Integration in Developmental Dyslexia. J Neurosci. 2024;44(3):e0944232023.
52. Evans TM, Flowers DL, Napoliello EM, Eden GF. Sex-specific gray matter volume differences in females with developmental dyslexia. Brain Struct Funct. 2014;219(3):1041-54.
53. Chyl K, Kossowski B, Dębska A, Łuniewska M, Marchewka A, Pugh KR, et al. Reading Acquisition in Children: Developmental Processes and Dyslexia-Specific Effects. J Am Acad Child Adolesc Psychiatry. 2019;58(10):948-60.
54. Yang L, Li C, Li X, Zhai M, An Q, Zhang Y, et al. Prevalence of Developmental Dyslexia in Primary School Children: A Systematic Review and Meta-Analysis. Brain Sci. 2022;12(2):240.
55. Zhao H, Zhang B, Chen Y, Zhou X, Zuo P. Environmental Risk Factors in Han and Uyghur Children with Dyslexia: A Comparative Study. PLoS One. 2016;11(7):e0159042.
56. El Sheikh MM, El Missiry MA, Hatata HA, Sabry WM, El Fiky AAA, Essawi HI. Frequency of occurrence of specific reading disorder and associated psychiatric comorbidity in a sample of Egyptian primary school students. Child Adolesc Ment Health. 2016;21(4):209-16.
57. Migliavaca CB, Stein C, Colpani V, Barker TH, Ziegelmann PK, Munn Z, et al. Meta-analysis of prevalence: I(2) statistic and how to deal with heterogeneity. Res Synth Methods. 2022;13(3):363-7.
58. Sharifi AA, Davari R. prevalence of reading disorder a among primary school students in Shahrekord. Journal of Exceptional Children. 2009;8(4):413-8.
59. Hosseinaee A, Aghajani A, Nofresti A. Prevalence of reading and writing disabilities among primary school students. Developmental Psychology: Journal of Iranian Psychologists. 2011.
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| Issue | Vol 20 No 2 (2025) | |
| Section | Review Article(s) | |
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| Dyslexia Meta-Analysis Prevalence Students Systematic Review | ||
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How to Cite
1.
Sakhai F, Mazaheri S, Golmohammadi G, Asadollahpour F. Prevalence of Developmental Dyslexia among Primary School Children in Iran: A Systematic Review and Meta-Analysis. Iran J Psychiatry. 2025;20(2):223-240.
