|Year : 2017 | Volume
| Issue : 1 | Page : 17-25
Prevalence and etiology of communication disorders in children attending Alexandria University Children’s Hospital, Egypt
Bayoumi A Gharib1, Manal M El Banna2, Mona Khalil1, Mai M Abou Heikal1
1 Department of Pediatrics, Faculty of Medicine, Alexandria University, Alexandria, Egypt
2 Phoniatrics Unit, Department of Otorhinolaryngology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
|Date of Submission||11-Jan-2017|
|Date of Acceptance||15-Mar-2017|
|Date of Web Publication||12-Jul-2017|
Department of Pediatrics, Faculty of Medicine, Alexandria University, Alexandria, 21526
Source of Support: None, Conflict of Interest: None
Background Communication development in children usually follows a fairly predictable pattern, paralleling general cognitive development. Any problem in communication is likely to have a significant effect on a child’s social and academic skills and behavior.
Objective The aim of this study was to estimate the prevalence and determine the possible etiologies of communication disorders in children attending the Outpatient Clinic of Alexandria University Children’s Hospital.
Patients and methods Children attending the Outpatient Clinic of Alexandria University Children’s Hospital during a period of 6 months within the age range of 3–6 years were included in the study. A noninterventional descriptive cross-sectional hospital-based study was used. A structured questionnaire was used to identify communication complaints and their types from the parents’ perspectives besides their sociodemographic data. Children with positive complaints were evaluated using National Health Services-Lothian Guidelines for Referral to Speech and Language Therapy. The studied children underwent neurodevelopmental assessment and physical examination to identify possible etiologies of communication disorders and their distribution.
Results In the studied sample of 280 children, the prevalence of significant communication complaints was 23.2% and the prevalence of confirmed communication disorders was 10%. The total prevalence of confirmed delayed language development (DLD) in the studied sample was 6.4%; 1.8% of the had specific language impairment, 1.4% had environmental DLD, 1.4% had DLD due to mental retardation, 1.1% had DLD associated with attention deficit hyperactivity disorder, and 0.7% had DLD due to autism spectrum disorders. The total prevalence of confirmed speech disorders in the studied sample was 3.2%; motor and speech-sound defects constituted 2.1% of the studied sample, 0.7% had dysfluency, and 0.4% had postadenoidectomy hypernasality. The total prevalence of confirmed voice disorders in the studied sample was 0.4%, with vocal polyp. Moreover, the study showed that sex, history of perinatal/postnatal events, and presence of medical health problems had significant effects on children’s communication development.
Conclusion Communication disorders are common in pediatric patients. Sex, history of perinatal events, and presence of significant comorbid medical conditions are significant risk factors for developing communication disorders. Parents’ awareness of communication development is poor, and pediatricians need to be more aware of communication development assessment, management plan of communication disorders, and referral indications.
Keywords: children, communication disorders, Egypt, language, prevalence, speech, voice
|How to cite this article:|
Gharib BA, El Banna MM, Khalil M, Abou Heikal MM. Prevalence and etiology of communication disorders in children attending Alexandria University Children’s Hospital, Egypt. Alex J Pediatr 2017;30:17-25
|How to cite this URL:|
Gharib BA, El Banna MM, Khalil M, Abou Heikal MM. Prevalence and etiology of communication disorders in children attending Alexandria University Children’s Hospital, Egypt. Alex J Pediatr [serial online] 2017 [cited 2018 Jul 15];30:17-25. Available from: http://www.ajp.eg.net/text.asp?2017/30/1/17/210440
| Introduction|| |
Communication is fundamental to human functioning; it includes the interchange of thoughts, opinions, or information through speech, writing, or signs from a sender to a receiver through some media toward a mutually accepted goal or direction . Language is a system of communication involving a set of small units (syllables or words) that can be combined to yield larger language forms (phrases and sentences) that have understandable meanings within a group or community . Voice (or vocalization) is the sound produced by humans and other vertebrates using the lungs and the vocal folds in the larynx . Speech is the method of verbal language communication that involves the oral production and articulation of words as a result of specific motor behaviors and requires precise neuromuscular coordination of respiration, phonation, resonance, and articulation systems .
Speech development is a gradual process requiring years of practice . Language development occurs most rapidly between 2 and 5 years. Vocabulary increases from 50 to 100 words to more than 2000 and sentences incorporate all major grammatical components. Language milestones have been found to be largely universal across languages and cultures, with some variations depending on the complexity of the grammatical structure of individual languages. Although the sequences are predictable, the exact timing of achievement is not, and there are marked variations among normal children .
Several factors affect language development, including antenatal care, Apgar scores, birth weight, premature delivery, birth order, parental education, environmental factors, sex of the children, and family history with specific language impairment (SLI) . Young children with cognitive delays, autism, and other general developmental disabilities almost always experience general delays in their language development. The severity of these language disorders usually varies according to the severity of the child’s primary disability .
Communication disorders, in preschoolers, include any atypical disorders in comprehension or production of speech sounds (i.e. consonants and vowels), words, phrases, or sentences. Communication disorders include delayed language development (DLD), which may be isolated or due to, for example, hearing loss, brain damage, attention deficit disorders, autism spectrum disorders (ASD), speech disorders (e.g. articulation errors, fluency disorders, and resonance disorders), and voice disorders due to organic or nonorganic causes. A communication disorder may range in severity from mild to profound; it may be developmental or acquired and primary or secondary. Individuals may demonstrate one or any combination of communication disorders .
Disorders of speech and language affect up to 8% of preschool-aged children . A survey in Texas for voice disorders showed that between 2.4 and 3.4% demonstrated clinically significant problems . Prevalence rates vary not only according to the age group and how the data were collected but also according to the criteria for determining impairment . Studies that have addressed the magnitude of communication disorders among Egyptian Arabic-speaking children are scarce . The current study represents one of the fewest studies providing information about the prevalence of communication disorders in Egypt.
| Aim|| |
The present work aimed at estimating the prevalence and determining the possible etiology of communication disorders in children attending the Outpatient Clinic of Alexandria University Children’s Hospital (AUCH).
| Patients and methods|| |
Children attending the Outpatient Clinic of AUCH during the morning shift, from 9.00 am until 12 pm, during a period of 6 months were included. A sample size of 280 children of both sexes, fulfilling the inclusion criteria − age range of 3–6 years and seeking medical advice for any pediatric complaint or a communication complaint − was included in this study; however children outside the age range, those previously diagnosed with neuropsychiatric problems, or under interventional management of diagnosed neurodevelopmental disorders [e.g. global developmental delay (GDD), or cerebral palsy (CP)] were excluded.
A cross-sectional hospital-based study design was used.
The study was conducted at the Outpatient Clinic of AUCH during a period of 6 months, from April 2014 to September 2014.
Data were collected using two tools to achieve the aim of the study.
The Personal Data of the Child and Primary Caregivers’ Questionnaire for early identification of children exposed to communication disorders and collection of sociodemographic data, structured and directed to parents of Arabic-speaking preschool children, in the form of yes/no questions .
National Health Service (NHS)-Lothian Guidelines for Referral to Speech and Language Therapy , which evaluates the significance of communication complaints for age, classifying them into not significant complaints that do not necessarily need referral, complaints that need to be monitored, and significant complaints that need referral to speech and language therapy.
Approval of the Ethics Committee of Alexandria University was obtained. The necessary official permissions from different authorities were obtained before the conduct of the study. Informed consent was obtained from children’s primary caregivers to participate in the study including the explanation of the aim of the study and the confidentiality of obtained data.
The study tools were tested for their reliability. This was achieved by application of the parents’ questionnaire and the NHS guidelines on 20 children, who were chosen randomly. The study tools were of very good reliability as both Cronbach’s α (internal consistency) and κ agreement (stability) of the tools items were greater than 0.7.
Using the Modified Score for Social Level of Families after Fahmy and Sherbiny , the socioeconomic class of the studied children’s families were determined.
The parents’ questionnaire (tool I) was answered by the parents of the targeted children, and children were grouped according to the presence of communication complaints into positive and negative children, and positive complaints were classified into speech, language, and voice complaints. Children with positive complaints were evaluated according to the NHS-Lothian Guidelines for Referral to Speech and Language Therapy (tool II).
The studied children were exposed to neurodevelopmental assessment and physical examination, to identify the possible etiologies of communication disorders and their distribution in the study sample. Stanford Binet IQ testing and Diagnostic and statistical manual of mental disorders, 4th ed., clinical criteria for diagnosing attention deficit hyperactivity disorder (ADHD) and ASDs were applied on some of the cases guided by history and assessment.
Children with significant complaints, according to the NHS-Lothian Guidelines for Referral to Speech and Language Therapy, were referred to Alexandria University Unit of Phoniatrics for formal evaluation to confirm the diagnosis of communication disorder.
Data were collected, revised, coded, and fed to statistical software IBM SPSS (version 20; IBM, North Castle Drive, Armonk, NY, USA). All statistical analyses were performed using two-tailed tests and alpha error of 0.05. The following statistical tests were used:
- Descriptive statistics, which included frequencies and percentages, to describe categorical data.
- Analysis of categorical data, using Pearson’s χ2-test and Monte Carlo exact test to identify the associations between variables.
| Results|| |
[Table 1] shows the sociodemographic data of the studied children. Most of the cases were male patients (66.4%), of the first birth order or a single child (49.6%), and were taken care of by both parents (97.9%). Consanguinity was positive in only 27.1% of the parents of the studied children, and most of their families were of low socioeconomic class (64.9%).
[Table 2] shows that 47.5% of the studied children had significant perinatal/postnatal history as reported by their parents, such as preterm or post-term labor, twin pregnancy, neonatal hypoxia, low birth weight, neonatal hyperbilirubinemia, or the need for neonatal intensive care admission. Only 31.8% of the studied children have a significant medical condition at present or are being treated for a chronic illness or major surgeries that may affect their growth and development (e.g. chronic renal failure, congenital heart diseases, intestinal anomalies, major surgeries, etc.). Finally, 34.6% of the whole sample had a positive family history of communication complaints or disorders.
[Table 3] shows the distribution and prevalence of communication complaints and their types across the studied sample according to tool I. Positive complaints were found in 56.1% of the sample.
|Table 3 Prevalence of communication complaints in the studied sample (n=280)|
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[Table 4] shows the results of application of tool II on the positive children; it demonstrated that 39.5% of the parent’s positive complaints were not significant for age (i.e. clinically need only assurance), 41.4% of the positive complaints were significant for age, indicating a deviation from normal communication development and needed referral, and 19.1% of the positive complaints needed monitoring by the parents and physician.
|Table 4 Distribution of positive complaints after evaluation by National Health Service-Lothian Guidelines for Referral to Speech and Language Therapy (n=157)|
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[Table 5] shows a detailed combined distribution of the positive communication complaints divisions provided by the parents questionnaire and evaluated using NHS-Lothian Guidelines for Referral to Speech and Language Therapy, indicating that the type of complaints and its significance for age are significantly linked. The table shows that the majority of the significant complaints were combined speech and language complaints and the majority of the not significant complaints were speech complaints.
|Table 5 A detailed distribution of the evaluated complaints using National Health Service-Lothian Guidelines for Referral to Speech and Language Therapy (n=157)|
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[Table 6] shows that, on comparing the percentage of positive patients with the total number of male and the total number of female patients, communication complaints were found to be more prevalent among male patients than among female patients with a percentage of 62.9% for boys compared with 42.6% girls. The percentages of boys with significant complaints, not significant complaints, and complaints needing monitoring were greater than that of girls, with a statistically significant distribution (P=0.005). No other statistically significant relations were detected with regard to other sociodemographic parameters.
|Table 6 Relation between sociodemographic data and the combined distribution of the studied sample according to the parents questionnaire and National Health Service-Lothian Guidelines for Referral to Speech and Language Therapy (n=280)|
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[Table 7] shows the relation between the evaluated positive communication complaints using NHS-Lothian Guidelines for Referral to Speech and Language Therapy and the distribution of perinatal/postnatal history, medical history, and family history among the positive cases. There was a significant statistical relation between the child’s perinatal/postnatal history and significance of the child’s complaints. Moreover, there was a significant statistical relation between the child’s medical history and the significance of the child’s complaints.
|Table 7 Relation between the evaluated positive communication complaints using National Health Service-Lothian Guidelines for Referral to Speech and Language Therapy and the distribution of perinatal/postnatal history, medical history, and family history among the positive cases (n=157)|
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[Table 8] shows a detailed distribution of etiological conditions among the divisions of children with positive complaints evaluated using NHS-Lothian Guidelines for Referral to Speech and Language Therapy. Among most of the isolated cases that had no etiology, the complaints were not significant. The highest percentage of cases with the following etiological conditions had communication complaints that were significant: environmental factors having a poor communicative environment, GDD, mental retardation (MR), adenoids and related problems, CP, and ASD. As for hearing impairment, it was found in 60% of cases with complaints that needed monitoring giving a history of recurrent otitis media compared with 40% of the significant cases with evidence of sensory neural hearing loss and history of cochlear implants. As for children with ADHD, the cases were equally distributed between cases of positive significant and the positive not significant complaints. As regards orofacial defects, including dental problems and cleft lip, most of the cases (66.7%) were found to have not significant complaints.
|Table 8 Detailed distribution of etiological conditions among the divisions of children with positive complaints evaluated using National Health Service-Lothian Guidelines for Referral to Speech and Language Therapy (n=157)|
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On the basis of the previous results, 65 of 280 (23.2%) studied children with the reported complaints by the parents were found significant, indicating the presence of a communication disorder that needs referral to speech and language therapy according to NHS guidelines. To achieve the aim of the study, those significant cases were directed to Alexandria University Phoniatrics Unit to confirm the presence of a communication disorder. Of the 65 children, 28 (10%) children had been evaluated with 100% confirmation, whereas the remaining 37 cases were not evaluated or confirmed only due to lack of compliance, which reflects the lack of awareness of this developmental domain among the parents.
[Table 9] shows the prevalence of the confirmed communication disorders (28 cases) in the whole studied sample (280 cases). Most of the cases (18 cases) were diagnosed with DLD. Nine cases were confirmed to have speech disorders, and only one case was diagnosed with voice disorder due to vocal polyp.
|Table 9 Prevalence of the confirmed communication disorders (n=28) in the studied sample (n=280)|
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A final finding to highlight, reflecting the amount of awareness of communication development and disorders among both the community and physicians, was that only the parents of 19.7% of the 157 children with positive complaints were aware and concerned about their child’s communication development and sought medical advice of physicians of different specialties. Only 32.3% of those parents were referred to phoniatricians for specialized consultation, whereas 67.7% were misdirected.
| Discussion|| |
Communication disorder is a broad term that includes a variety of different disorders . Appropriate planning of speech and language services to children depends on adequate epidemiological data, such as prevalence . Multiple studies have investigated the prevalence of communication disorders throughout the world and results varied according to the type of communication disorders being investigated, how it is defined, methods used to identify it, age, and number of the studied sample , and hence comparison across most studies is difficult .
By using the personal data of the child and primary caregivers’ questionnaire for early identification of children exposed to communication disorders, the total prevalence of communication complaints in the studied sample children was 56.1%. Gad-Allah et al.  reported that 44.4% of their studied sample had communication disorders using the same parent questionnaire. Both studies differ in the study setting. Keating et al. (quoted in Zimmerman et al. ) used parent report similar to our current study on Australian children, for the same communication disorders, and reported the prevalence to be 1.7%, but their age range was broader (0–14 years). In our study, the prevalence of delayed language complaints was 6.1%, prevalence of speech complaints was 26.4%, prevalence of combined language and speech complaints was 22.1%, and the prevalence of voice complaints was 1.4% in the studied sample. In the study by Gad-Allah et al. , 30.8% of the studied sample had DLD, 44.8% had speech disorders, and 2.4% had change in voice, but nothing was mentioned about combined complaints.
After evaluation of yielded complaints by the NHS-Lothian Guidelines for Referral to Speech and Language Therapy, our study showed that the type of complaints and the significance of the complaint for age are significantly linked when combined complaints tend to be more significant. Broomfield and Dodd  indicated that diagnosis of the type and level of severity are linked using the therapy outcome measures impairment levels. In their study, over two-thirds of referrals were classified as having a moderate or mild disability in terms of therapy outcome measures’ criteria, and only 12% were classified as having severe or profound levels of severity. Our study showed that 39.5% of the positive complaints were not significant for age, 19.1% of the positive complaints needed monitoring, and 41.4% of the positive complaints were significant for age and needed referral in terms of NHS-Lothian Guidelines for Referral to Speech and Language Therapy. The majority (61.3%) of the combined speech and language complaints were significant, whereas the majority of isolated speech complaints or isolated language complaints were not significant for age, and 75% of voice complaints needed monitoring. In the study by Broomfield and Dodd , the proportion of children with profound levels of severity was high for receptive language disorder but low for children with speech disorders. The proportion of children with moderate levels of severity for speech difficulties was high.
By observing the effect of sociodemographic characteristics of the studied sample on communication disorders in the present study, it was found that communication complaints were significantly more prevalent among boys than among girls with a ratio of 1.5 : 1. This nearly goes in line with the study by Zimmerman et al. , who reported a male-to-female ratio of 1.8 : 1, and with the literature review by Law et al.  that concluded that the male: female ratio ranged between 1.3 : 1 and 2.3 : 1. Broomfield and Dodd  stated that the literature suggests a decreasing prevalence of communication disorders with increasing age. To some extent, our study is in agreement with the literature, as communication complaints were found to be more prevalent among children aged 3 years and least prevalent among children who were 6 years of age. Moreover, the prevalence of significant cases among the 3-, 4-, 5-, and 6-year olds were decreasing with age. Chaimay et al.  reported that the later born children compared with first-born or the single children are 1.5 times more likely to have SLI compared with children of the first birth order. In the present study, but for all communication disorders, it was also found that communication complaints are more prevalent among children of the second birth order with a percentage of 60.7%; however, the highest percentage of significant complaints was among children of the first birth order, which included the single children, after evaluation with NHS-Lothian Guidelines for Referral to Speech and Language Therapy.
In the present study, the effect of socioeconomic classes is not evident on the overall prevalence of positive complaints across different levels. In agreement with that, Broomfield and Dodd  reported that social background is known to be related to the rate of language development; however, the link with language impairments is not strong. Moreover, Mckinnon et al.  stated that there was no significant difference in the pattern of prevalence across different socioeconomic classes. Chaimay et al.  reported that children with Apgar scores of 0–3 at 5 min after birth are two times more likely to have SLI, and birth weight was a risk for unsatisfied language development outcome. The study by Chaimay et al.  showed lower scores in both language comprehension and production in prematurely born children. In our study, we found that 70% of children whose parents reported perinatal/postnatal events later revealed positive communication complaints. We also found that with increasing significance of the complaints for age according to NHS-Lothian Guidelines for Referral to Speech and Language Therapy, the percentage of children with positive perinatal/postnatal history significantly increases, reaching 70% of children with significant complaints. The literature review by Chaimay et al.  states that children with a family history of SLI tend to be at a greater risk for SLI than those in families without SLI. This is true for both male and female populations. Agreeing to some extent, but for all communication disorders, the present study found that 60% of children who reported a positive family history of communication disorders revealed positive communication complaints. Moreover, with increasing significance of the complaints for age in terms of NHS-Lothian Guidelines for Referral to Speech and Language Therapy, the percentage of children with positive family history increases, reaching 44.6% of children with significant complaints.
In the current study we demonstrated a detailed distribution of the etiological conditions of communication disorders, discovered among children with positive complaints after evaluation with NHS guidelines. Isolated cases that have no etiology mostly had not significant complaints. The highest percentage of the following etiological conditions was found among the cases with significant complaints: environmental factors creating a poor communicative environment, GDD, MR, adenoids-related problems, CP, and ASDs. Broomfield and Dodd  mentioned that the severity of impairment was related to the amount of comorbidity observed. In the current study, for hearing impairment, it was found in 60% of cases with complaints that needed monitoring, giving a history of recurrent otitis media, compared with 40% among the significant cases with evidence of sensory neural hearing loss and history of cochlear implants. Broomfield and Dodd  mentioned the effect of intermittent hearing difficulty to remain unclear.
In the present study the prevalence of significant communication complaints in the studied sample of 280 children was 23.2%; 13.2% failed confirmation due to lack of compliance, and hence the prevalence of confirmed communication disorders after evaluation at Alexandria University Phoniatrics Unit was 10% of the total. Aboul-Oyoun  found that the overall prevalence of communication disorders was 7.9% in a performed epidemiological study of communication disorders in Assiut, Upper Egypt, on 3171 referred children to the hospital seeking professional advice, whereas Zimmerman et al.  reported a prevalence estimate of 6.3%.
In the present study, the total prevalence of confirmed DLD in the studied sample was 6.4%: 1.8%, isolated DLD; 1.1%, DLD associated with ADHD; and 0.7%, DLD due to ASD. Gad-Allah et al.  revealed that 19.7% of their studied samples had DLD without apparent cause, 7% had DLD due to ADHD, 2.8% had DLD due to ASD, and 1.3% had DLD due to hearing impairment, with a total of 30.8% using parent questionnaire only. In addition the present study revealed that 1.4% had environmental DLD and 1.4% had DLD due to MR, whereas DLD due to hearing impairment were missed in patients who failed confirmation due to lack of compliance.
The total prevalence of confirmed voice disorders in the studied sample was 0.4% and the cases were diagnosed with vocal polyp. Duff et al.  reported that the prevalence of voice disorders in their sample of preschoolers was 3.9%. In the study by Gad-Allah et al.  2.4% of the studied samples had change in voice using parent’s report only.
The total prevalence of confirmed speech disorders in the studied sample was 3.2%. The incidence of motor and speech-sound defects was 2.1% in the studied sample; 1% had isolated articulation disorders, 0.7% had associated ADHD, and in 0.4% it was associated with CP. Moreover, 0.7% had dysfluency and 0.4% had postadenoidectomy hyper nasality. Nearly similar results were reported by Tomblin et al. (quoted in Zimmerman et al. ), who showed that the prevalence of speech delay was 3.8% in English-speaking kindergarten children. Moreover, Mckinnon et al. , using a four-stage method for identification and confirmation, revealed that the estimated prevalence of stuttering was 0.33%, that of voice disorders was 0.12%, and for speech-sound disorders it was 1.06%. However, Gad-Allah et al.  revealed that 24.1% of the studied samples had articulation errors, 2.8% had resonance disorder, and 17.8% had dysfluency, with a total of 44.8% of the studied sample having speech disorders, using the parent questionnaire only.
Finally, we found that only the parents of 19.7% of children with positive complaints were aware and concerned about their children communication development and sought medical advice of physicians of different specialties. While choosing the exclusion and inclusion criteria of the present study we excluded children with previously diagnosed neurodevelopmental conditions, to use the communication complaints that would be yielded and to track the possibility of the presence of underlying etiological undiagnosed neurodevelopmental conditions. Children with MR, ASDs, CP, and attention deficit disorder in the study sample who were not previously diagnosed and their parents were completely unaware of the possibility of presence of an underlying etiology of their children’s problems in communication were also excluded. Jessup et al.  reported that less than 30% of the parents of kindergarten students attending schools who were found to have language impairment had previously been made aware of their child’s communication difficulties, or had accessed speech-language pathology services.
| Conclusion|| |
Communication complaints and significant communication disorders are common in pediatric patients.
Sex, history of perinatal events, and presence of significant medical conditions are significant risk factors for developing communication disorders, whereas age, child order, consanguinity, socioeconomic class and family history are considered less strong risk factors.
Communication disorders are mostly isolated or can be a result of a poor surrounding communicative environment of the child or can be an early sign, an association, or an outcome of some medical conditions such as ASDs, CP, MR, hearing impairments, ADHD, etc.
Parents’ awareness of communication development is poor and pediatricians need to be more minded of communication development, assessment, management plan, and referral indications of communication disorders.
Construction of a national screening protocol for preschool children in Egypt attending major hospitals to determine the magnitude of the problem.
Designing of native guidelines to aid pediatricians to evaluate the significance of communication complaints and to highlight the indications for referral for formal testing and evaluation at specialized phoniatrics clinics.
Moreover, raising the awareness of parents and pediatricians about communication development and disorders is essential.
The authors wish to thank Heba Gad-Allah, Samar Abdel Raouf, Tamer Abou Elsaad, Mahasen Abd Elwahed, authors of the research ‘Identification of communication disorders among Egyptian Arabic-speaking nursery schools’ children’ conducted at Dakahlia Governorate, especially Prof. Tamer Abou El Saad for giving us the permission to use one of their study tools and providing us with their designed parent’s questionnaire to use in our study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Gad-Allah H, Abd-Elraouf S, Abou-Elsaad T. Identification of communication disorders among Egyptian Arabic-speaking nursery schools’ children, Mansoura University, Mansoura. Egypt J Ear Nose Throat Allied Sci 2012; 13:83–90.
Simms M, Schum R. Learning disorders. In: Kliegman R, Stanton B, Schor N, Geme J, Behrman R, editors. Nelson textbook of pediatrics. 19th ed. Philadelphia: Saunders; 2011. pp. 114–119.
Chaimay B, Thinkhamrop B, Thinkhamrop J. Risk factors associated with language development problems in childhood – a literature review. J Med Assoc Thai 2006; 89:1080–1086.
Duff M, Proctor A, Yairi E. Prevalence of voice disorders in African American and European American preschoolers. J Voice 2004; 18:348–353.
Fahmy S, El-Sherbini AF. Determining sample parameters for social classification for health research. Bull High Inst Public Health 1983; 13:59–108.
McKinnon D, Mcleod S, Reilly S. The prevalence of stuttering, voice, and speech-sound disorders in primary school students in Australia. Lang Speech Hear Serv Sch 2007; 38:5–15.
Zimmerman J, Satterfield R, Miller J, Bilder D, Hossain S, McMahon W. Communication disorders: prevalence and comorbid intellectual disability, autism, and emotional/behavioral disorders. Am J Speech Lang Pathol 2007; 16:359–367.
Broomfield J, Dodd B. Children with speech and language disability: caseload characteristics. Int J Lang Commun Disord 2004; 39:303–324.
Law J, Boyle J, Harris F, Harkness A, Nye C. Prevalence and natural history of primary speech and language delay: findings from a systematic review of the literature. Int J Lang Commun Disord 2000; 35:165–188.
Aboul-Oyoun A. Epidemiological study of communicative disorders in Upper Egypt [MD thesis]. Cairo, Egypt: Faculty of Medicine, Ain Shams University; 2000.
Jessup B, Ward E, Cahill L, Keating D. Teacher identification of speech and language impairment in kindergarten students using the kindergarten development check. Int J Speech Lang Pathol 2008; 10:449–459.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9]