Prevalence and clinical characteristics of dyslexia in primary school students.

BACKGROUND: Dyslexia is the most common subtype of learning disabilities with a prevalence ranging from 5-10 per cent. The central difficulty in dyslexia is the phonological awareness deficit. The authors have developed a screening test to assess the reading ability of Thai primary school students. OBJECTIVE: 1. To study the prevalence of dyslexia in first to sixth grade students at Wat Samiannaree School. 2. To study the clinical characteristics such as sex, neurological signs, verbal intelligence and comorbid attention deficit hyperactive disorder (ADHD) of the dyslexia group. METHOD: A total of 486 first to sixth grade students were administered "Raven's progressive matrices test" for estimation of intellectual functioning. Those who scored below the fifth percentile were labeled as mental retardation and excluded from the study. The students' reading ability was evaluated by 3 steps; first by classroom teachers using some items of the screening test, second by the researchers examining some more items individually, and third by the special educator assessing more details in reading and phonology. The students who had a reading ability two-grade levels below their actual grades and impairment in phonology were diagnosed with dyslexia. RESULTS: The prevalence of dyslexia and probable dyslexia were found to be 6.3 per cent and 12.6 per cent, respectively. The male to female ratio of dyslexia was 3.4:1. The dyslexia group had significantly lower Thai language scores than those of the normal group (p < 0.05). All of the dyslexia group had a normal grossly neurological examination but 90 per cent showed positive soft neurological signs. Mean verbal intellectual quotient score in the dyslexia group assessed by using Wechsler Intelligence Scales for Children--Revised was 76 +/- 7. The comorbid ADHD was 8.7 per cent in the dyslexia group. CONCLUSION: Dyslexia was a common problem among primary school students in this study. Further studies in a larger population and different socioeconomic statuses are required to determine the prevalence of dyslexia in the general population. The authors suggest evaluating the reading ability carefully by using a test that can detect phonological awareness deficit in all children who have learning problems.

Risk factors of relapse within eight weeks after an acute asthma exacerbation in Thai children.

BACKGROUND: Acute asthma relapse following treatment and discharge from hospital remains a substantial problem. Various potential risk factors for relapse have been reported including age, sex, frequency of hospitalization and emergency medications. All these factors, however, may not be generalized for all patients because of difference in prevalence, trigger factors, types of allergens, medical accessibility and psychosocial problems. OBJECTIVE: To identify factors associated with relapse following treatment for acute asthma within the next 8 weeks in Thai children. MATERIAL AND METHOD: The authors prospectively followed 91 children discharged from Ramathibodi Hospital after treatment of an asthma attack from June 1999 to December 2000. Parents were surveyed concerning their child's medical history, trigger factors, psychosocial and economic variables. Data on severity of the attack, asthma scores, emergency treatment, and response to treatment were recorded. Investigations included eosinophil count, total IgE, serum eosinophil cationic protein (ECP), skin test, methacholine bronchial challenge test, and IQ test were performed and recorded. RESULTS: Within the first week, only 6.6 per cent had relapsed and increased to 29.7 per cent by 8 weeks. Patients who suffered relapse were more likely associated with age at asthma diagnosis (OR, 2.90; 95% CI, 1.1-7.5) and 6 years of age or under (OR 4.49, CI 1.22-16.54). From the investigation results including eosinophil count, total IgE, serum ECP, skin test, methacholine bronchial challenge test, and IQ test, there was no significant difference in the factors between patients who suffered relapse and those who did not. From the psychosocial evaluation, 18 out 39 (46.2%) studied cases had significant psychosocial disorders. They were 4 cases with delayed development and mental retardation, 9 cases with parent-child relation problems, and 2 cases with serious intrafamilial disorders. Most of these patients were non-relapse cases. However, the relationship between asthma relapse and psychosocial disorders could not be ascertained since psychosocial evaluation was only performed in one-third of the study population. CONCLUSION: Among patients following acute asthma therapy, 29.7 per cent will have a relapse. The authors identified the age at onset of asthma before the age of 6 years as an important risk factor. This may help to decrease the relapse rate by more intensive and comprehensive management among patients at high risk.