Secondary Logo

Epidemiology of autism in Singapore: findings of the first autism survey

BERNARD-OPITZ, V.*; KWOOK, K.-W.; SAPUAN, S.

International Journal of Rehabilitation Research: March 2001 - Volume 24 - Issue 1 - p 1-6
Standard Papers
Free

The report describes the results of a survey conducted on 176 parents of children with autism in Singapore. The ages of the children ranged from 3 to 12 years. The survey focused on the child's background, behaviour problems and skill profile, the home and school situation as well as the linguistic and social background. It was noted that the Singapore population confirms the international distribution regarding a predominance of boys over girls and a low incidence of birth complications. A positive trend noted was the fact that 60% of the children were diagnosed before the age of 3 years. Discussion focuses on possible risk factors and psychosocial adversities for autism such as a high frequency of caregivers who are foreign maids, the use of multiple languages and the high level of punitive educational practices. The possible influence of psychosocial deprivation on child development is discussed.

National University of Singapore, Singapore

*Address for correspondence: Department of Social Work and Psychology, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260

Back to Top | Article Outline

Introduction

Epidemiological studies on autism have been reported for England (Lotter, 1967; Rutter, 1978; Wing, 1993), Sweden (Gillberg and Schaumann, 1982), Norway (Sponheim and Skjeldal, 1998), Canada (Bryson et al., 1988a), and the United States (Ritvo et al., 1983). In Asia, studies have been conducted in China (Tao, 1982, 1987), Hong Kong (Chung et al., 1990) and Japan (Tanoue et al., 1988; Kobayashi et al., 1992). Prevalence estimates range from 4–5 to 10 persons with autism per 10 000 populations. Recent research (Gillberg, 1992; Wing, 1997) has suggested a spectrum of autistic conditions with rates of 20 to 48 per 10 000.

The situation of children with autism in Singapore was relatively unexplored until 1989. While Goh and Bose (1980) reported on childhood schizophrenia, children with autism were diagnosed by Bernard-Opitz only from 1987 onwards. Since 1989 structured behavioural programmes have been offered (Bernard-Opitz, 1993, 1996). Diagnosis and treatment services for people with autism have expanded and diversified since then.

In contrast to most other countries with epidemiological studies on autism, Singapore is a multiethnic and multilingual nation, with three main ethnic groups: Chinese, Malays and Indians. Although English, Mandarin, Malay and Tamil are official languages, more than 30 languages are in use. Unlike the situation in many other countries, Singaporean children are exposed to multiple caregivers and a highly demanding educational system. A core objective of the research therefore was to assess patterns in the assessment, care, education and treatment of children with autism within such a complex cultural setting. Questions regarding the influence of a multicultural and multilingual environment on the skill profile of children as well as the influence of multiple caregivers constituted the focus of the questionnaire. In addition we wanted to collect preliminary data on the distribution of autism in Singapore.

Back to Top | Article Outline

Material and methods

Sample

Singapore has a resident population of about three million. Based on conservative estimates, indicating a prevalence of 4–5 to 10 cases per 10 000 population (Fombonne, 1998), the country can be expected to have 1200 to 3000 people with autism. Among these, 250 to 625 cases were expected below the age of 15 years. An attempt was made to survey 305 referred children with autism below the age of 12 years and to achieve as representative a sample as possible. A total of 176 cases was the basis of this study.

Singapore has a resident population of Chinese (78%), Malays (14%), Indians (7%), and others (1%). Our sample comprised 149 Chinese, 11 Malays, 9 Indians and 7 Eurasians. The income distribution, as reflected in the 1995 Household Survey, was as follows: lower income (30%), middle income (42%), and higher income (28%). Accordingly, the survey consisted of 34% lower income, 40% middle income, and 27% higher income.

Back to Top | Article Outline

Procedure

Most of the participants attended behavioural programmes offered through special schools or the Behavioural Intervention Centre for Children of the Department of Social Work and Psychology at the National University of Singapore. Some children were referred from hospitals and clinics such as the Child Psychiatric Clinic. The majority of the cases (71%) was diagnosed by the first author (V.B.-O.), a clinical psychologist, or by paediatricians (40%), with 5% diagnosed by a family doctor. Overlap of the data can be attributed to the confirmation of initial diagnosis through the psychologist. The first author used systematic observation methods in addition to the Autism Behaviour Checklist (Krug et al., 1978).

Since Singapore is a multilingual society in which English is the dominant working language, parents had the option of answering the questionnaire in English or in Mandarin. Questionnaires were distributed to parents through teachers in special schools, psychologists, and paediatricians. Telephone interviews were conducted to follow up on those who did not return the questionnaires. To make our sample more representative, the number of Chinese-speaking and lower-income parents was increased by conducting telephone interviews in Mandarin. Twenty-seven per cent of the sample was Chinese-speaking parents.

Back to Top | Article Outline

Questionnaire

The questionnaire consisted of 12 target areas with 100 multiple choices, which could be answered in about 15 minutes. An English as well as a Mandarin version of the questionnaire was distributed either by mail or through contact with the parents while waiting for treatment services. The first category of items gave a profile of the participant's sex and age, the timing of diagnosis, the birth and family history, behaviour problems and level of skills. The second category was subdivided into five sub-areas aimed at the assessment of care-giving arrangements, schooling, disciplinary methods and various medical and psychological interventions. The third category focused on the family's economic and linguistic background (Table 1).

Table 1

Table 1

Back to Top | Article Outline

Results

Preliminary analysis has yielded interesting results. The survey population of 176 comprised 81% boys and 19% girls, confirming the international distribution of about 3–4 boys to one girl (Creak and Ini, 1960; Bryson, 1996; Howlin and Moore, 1997). Our population ranged between 3 and 12 years with the distribution of the sample being skewed towards younger children. Two-thirds of the children were below the age of seven (Table 2). While the average age of diagnosis in the United Kingdom is 5–7 years of age (Howlin, 1999), in Singapore the population tends to be diagnosed at a younger age.

Table 2

Table 2

More than half of the parents noted problems in their children by the age of two; this compares well with findings by Howlin and Moore (1997). In our sample, 32% of the children were diagnosed at the age of two. Although there was a lag between the time when the first problem was noted and the time of diagnosis, nearly 60% were diagnosed by the age of three (Table 3). This result is of clinical relevance as the importance of early diagnosis and early intervention is often stressed (Siegel, 1996).

Table 3

Table 3

The vast majority of cases was diagnosed by a psychologist or a pediatrician. Family doctors diagnosed the children in only about 4.5% of the cases. At the time of the survey, multidisciplinary diagnostic teams were not available in Singapore (see Howlin, 1998 for a survey of diagnostic services in the United Kingdom).

In 95% of the cases pregnancy was normal with 88% of the parents reporting normal birth. Previous studies have reported figures of obstetrical complications (OCs) in about 25% of cases (Bryson et al., 1988b). The possible causal relationship between OCs and autism has recently been critically reviewed (Filipek et al., 1999). Data from a case–control study (Cryan et al., 1996) also have not supported the hypothesis that OCs increased the risk for autism. The low incidence of birth complications in our survey population is in line with current findings. In our survey, however, 21% of cases had family members with ‘mental or language problems’ (Table 4). This supports the hypothesis that biological or genetic factors are contributing causes for a subgroup of children with autism (Bryson, 1996).

Table 4

Table 4

The majority of children could not speak (71% had less than five words) and 62% mainly communicated through guiding the parents’ hands. In terms of parents’ perception of the child's main problem, the following were reported: behaviour problems (70%), ‘no speech’ (59%), odd play (36%), and aloofness (24%) (Table 5). The data supports the estimate that 50% of children with autism do not develop verbal communicaton (Prizant, 1996).

Table 5

Table 5

In 39% of the cases, both parents were working with the mother being the main caregiver in 63% of the cases. The number of cases with both parents working rose with income levels. Less than two-thirds of the children were looked after by their parents as main caregivers. Eight percent reported relatives and 28% foreign domestic helpers as main caregivers (Table 6). Commonly called ‘maids’ in Singapore, domestic helpers are women who are recruited from neighbouring countries such as the Philippines and Indonesia or from South Asia (e.g. Bangladesh, India, and Sri Lanka).

Table 6

Table 6

In light of the data, questions are raised concerning the role of parents in the care of children with autism. Another issue is the appropriateness of maids as main caregivers, as they do not speak English and local languages, are not trained in childcare, and are on short-term (e.g. two year) contracts.

In Singapore, it is not uncommon to have two to four (or more) languages spoken at home by parents, grandparents, siblings, relatives and maids; 70% of parents reported English as the main language spoken with the child. Other main languages used were: Mandarin (27%), Malay (3%) and Tamil (2%) (Table 7). Given the language impairment of children with autism, a multilingual environment and multiple caregivers present likely obstacles in childhood development.

Table 7

Table 7

The following methods of child rearing were used: positive reinforcement (92%), physical punishment (69%), reasoning (54%), token (30%) and time out (28%) (Table 8). The high incidence of physical punishment can be related to aversive disciplinary methods being more frequently used in Singapore (Fraser, 1987). Compared to a study of 7- to 9-year-old Singaporean children (Sim et al., 1986), our study on children with autism reflected higher frequency in the use of physical punishment and reasoning.

Table 8

Table 8

At the time of the study, 16% of the children were not served by any childcare or school programme. Thirty-two percent were in a one-to-one structured teaching programme (e.g., STEP), 36% were in private kindergartens or private programmes and 16% were in public kindergartens, public schools or special education classes (e.g., MINDS). Only 5% were enrolled in a public school (Table 9).

Table 9

Table 9

Among the specialists that the children had seen, the following distribution was obtained: psychologist (84%), speech therapist (67%), medical doctor (53%), occupational therapist (21%), sensory–motor therapist (10%) (Table 10). These professionals tend to be involved in services for children with autism (Howlin, 1998). Unlike Western countries, some Singaporean parents also turn to religious healers (2%). In follow-up interviews, some Chinese parents reported consulting temple spirit mediums (tang-ki), while Malay parents sought help through the ‘bomoh’ or ritual specialist. A few Christian respondents consulted ‘faith healers’ or participated in healing sessions.

Table 10

Table 10

Back to Top | Article Outline

Discussion

The present survey is the first overview study of children with autism in Singapore. Data from a sample of 176 cases from the three main racial subgroups revealed the following trends.

Biological factors such as the predominance of boys to girls (4 to 1), the low incidence of obstetrical complications (12%) and a family history of mental or language problems (21%) were comparable to international statistics. Although Singapore has a relatively short history of assessment and service provision for children with autism, the age of diagnosis, with 60% of the subjects being diagnosed before 3 years, is younger in Singapore than assessment age in the UK, which is between 5 to 7 years (Howlin, 2000).

Regarding the subjects’ skill profile and behaviour problems, only 30% of the children talk in sentences and the majority communicates through guiding the hand of the interaction partner (62%) or behaviour problems. Socio-economic factors such as a high prevalence of working parents, the involvement of foreign maids as caregivers and the use of multiple languages have to be considered as contributing to the skill level, behaviour problems and course of this pervasive developmental disability. Reports from social workers and psychologists suggest that there is a lack of stimulation in many homes; children were mainly just fed and kept clean; some were placed on a highchair in front of a TV up to 8 hours a day. This indicates a developmental risk-factor comparable to hospitalism and deprivation syndrome, which have been described as an effect of poor stimulation in orphanage settings. Because of the strong claims of genetic theory, psychosocial factors on child psychopathology such as these have been neglected until recently. Quasi-autistic patterns have been described following early global privation (Rutter et al., 1999). Crucial developmental milestones such as language, pretend play, shared attention and pointing are at risk when the interaction partners are inadequate models and fail to provide structures for such interaction (Kasari et al., 1993). Psychosocial adversities might have been underestimated in the local population and need to be assessed with more care. It cannot be excluded that the recently observed rise in the occurrence of autism in Singapore is related to psycho-social factors. Further studies should specify the type and quality of child-raising relationship and stimulation, since preventive efforts and early intervention are crucial to the prevention of lifelong disability.

This article is based on research made possible by a grant (RP 950024) from the National University of Singapore.

Back to Top | Article Outline

References

1. Bernard-Opitz, V. ( 1993). The STEP program. Autism News 1:9–10.
2. Bernard-Opitz, V. (1996). Treatment approaches to developmental disorders. Department of Social Work and Psychology, working paper no. 24.
3. Bryson, S.E. ( 1996). Brief Report: Epidemiology of autism. Journal of Autism and Developmental Disorders 26 ( 2):165–167.
4. Bryson, S.E., Clark, B.S. and Smith, I.M. ( 1988). First report on a Canadian epidemiological study of autistic syndromes. Journal of Child Psychology and Psychiatry 29 ( 4):433–445.
5. Bryson, S.E., Smith, I.M. and Eastwood, D.E. ( 1988). Obstetrical sub optimality in autistic children. Journal of the American Academy of Child and Adolescent Psychiatry 27:418–422.
6. Chung, S.Y., Luk, S.L. and Lee, P.W.H. ( 1990). A follow-up study of infantile autism in Hong Kong. Journal of Autism and Developmental Disorders 20:221–232.
7. Creak, M. and Ini, S. ( 1960). Families of psychotic children. Journal of Child Psychology and Psychiatry 1:156.
8. Cryan, E., Byrne, M., O'Donovan, A. and O'Callaghan, E. ( 1996). Brief Report: A case-control study of obstetric complications and later autistic disorder. Journal of Autism and Developmental Disorders 26 ( 4):453–460.
9. Filipek, P.A., Accardo, P.J., Baranek, G.T. et al. ( 1999). The screening and diagnosis of autistic spectrum disorders. Journal of Autism and Developmental Disorders 29 ( 6):439–484.
10. Fombonne, E. ( 1998). Epidemiological surveys of autism. in Volkmar, F.R. (Ed), Autism and Pervasive Developmental Disorders:32–63.
11. Fraser, A. (1987). Traditional and intellectual disability in Singapore. In Intellectual Disability: Perspectives and Challenges (edited by Chen, F. C., Fraser, A. S., Lyen, K. R., Oon, D., Tan, D. and Wong, M. K.). Proceedings of the 8th Asian Conference on Mental Retardation, Singapore, pp. 350–69.
12. Gillberg, C. ( 1992). The Emanuel Miller memorial lecture 1991: Autism and autistic-like conditions: subclasses among disorders of empathy. Journal of Child Psychology and Psychiatry 33:813–842.
13. Gillberg, C. and Schaumann, H. ( 1982). Social class and infantile autism. Journal of Autism and Developmental Disorders 12:223–228.
14. Goh, C.W. and Bose, P. ( 1980). A clinical profile of 100 child-patients with schizophrenia. Annals of the Academy of Medicine 8 ( 3):252–261.
15. Howlin, P. ( 1998). Information update: a survey of specialist autism diagnostic services in the UK. Autism 2 ( 2):205–211.
16. Howlin, P. (1999). Everyday problems: seminar on the treatment of autism. Johann Wolfgang Goethe-University Frankfurt/M, Department of Child and Adolescent Psychiatry.
17. Howlin, P. and Moore, A. ( 1997). Diagnosis in autism: a survey of over 1200 patients in the UK. Autism 1 ( 2):135–162.
18. Howlin, P., Mawhood, L. and Rutter, M. ( 2000). Autism and development receptive language disorder – a follow-up comparison in early adult life. Journal of Child Psychology and Psychiatry 41 ( 5):561–578.
19. Kasari, C., Sigman, M. and Yirmiya, N. ( 1993). Focused and social attention of autistic children in interactions with familiar and unfamiliar adults: a comparison of autistic, mentally retarded, and normal children. Development and Psychopathology 5:403–414.
20. Kobayashi, R., Murata, T. and Yosinga, K. ( 1992). A follow-up study of 201 children with autism in Kyushu and Yamaguchi areas, Japan. Journal of Autism and Developmental Disorders 22 ( 3):395–411.
21. Krug, D.A., Arick, J.R. and Almond, P.J. ( 1978). Autism Screening Instrument for Educational Planning, Portland, OR: ASIEP Educational Co..
22. Lotter, V. ( 1967). Epidemiology of autistic conditions in young children. Social Psychiatry 1:163–173.
23. Prizant, B.M. ( 1996). Brief Report: communication, language. Social and emotional development. Journal of Autism and Developmental Disorders 26 ( 2):173–177.
24. Ritvo, E.R., Freeman, B.J., Geller, E. and Yuwiler, A. ( 1983). Effects of fenfluramine on 14 outpatients with syndrome of autism. Journal of the American Academy of Child Psychiatry 22:549–558.
25. Rutter, M. ( 1978). Diagnosis and definition of childhood autism. Journal of Autism and Childhood Schizophrenia 8:139–161.
26. Rutter, M. et al. ( 1999). Quasi-autistic patterns following severe early global deprivation. Journal of Child Psychology and Psychiatry 40 ( 4):537–549.
27. Siegel, B. ( 1996). The World of the Autistic Child: Understanding Autistic Spectrum Disorders, New York: Oxford University Press.
28. Sim-Guan Kong, et al. ( 1986). Some aspects of child-rearing practices and their behavioural deviance. The Journal of the Singapore Paediatric Society 28 ( 1&2):94–103.
29. Sponheim, E. and Skjeldal, O. ( 1998). Autism and related disorders: epidemiological findings in a Norwegian study using ICD-10 diagnostic criteria. Journal of Autism and Developmental Disorders 28 ( 3):217–227.
30. Tanoue, Y., Oda, S., Osano, F. and Kawashima, K. ( 1988). Epidemiology of infantile autism in southern Ibaraki, Japan: differences in prevalence in birth cohorts. Journal of Autism and Developmental Disorders 18 ( 2):155–166.
31. Tao, K. ( 1982). The problems of diagnosis and classification of infantile autism. Journal of Chinese Neuropsychiatry 2:104.
32. Tao, K. ( 1987). Brief report: infantile autism in China. Journal of Autism and Developmental Disorders 17 ( 20):289–296.
33. Wing, L. ( 1993). The definition and prevalence of autism: a review. European Child and Adolescent Psychiatry 2:61–74.
34. Wing, L. ( 1997). The history of ideas on autism: legends, myths and reality. Autism 1 ( 1):13–23.
Keywords:

autism; epidemiology; Singapore

© 2001 Lippincott Williams & Wilkins, Inc.