J Autism Dev Disord (2017) 47:2363–2377 DOI 10.1007/s10803-017-3134-0
ORIGINAL PAPER
The Role of the Broader Autism Phenotype and Environmental Stressors in the Adjustment of Siblings of Children with Autism Spectrum Disorders in Taiwan and the United Kingdom Hsiao‑Wei Joy Tsai1 · Katie Cebula1 · Sue Fletcher‑Watson2
Published online: 13 May 2017 © The Author(s) 2017. This article is an open access publication
Abstract The influence of the broader autism phenotype (BAP) on the adjustment of siblings of children with autism has previously been researched mainly in Western cultures. The present research evaluated a diathesis-stress model of sibling adjustment using a questionnaire study including 80 and 75 mother-typically developing sibling dyads in Taiwan and the United Kingdom (UK). UK siblings reported elevated adjustment difficulties compared to the Taiwanese sample and to normative data. Whilst higher BAP levels were generally associated with greater adjustment difficulties, differences were found across cultures and respondents. Although significant diathesis-stress interactions were found, these were in the opposite direction from those predicted by the model, and differed across cultural settings. Implications for culturally-sensitive sibling support are considered.
This research formed part of Hsiao-Wei Joy Tsai’s doctoral dissertation in the Moray House School of Education, the University of Edinburgh, UK. * Hsiao‑Wei Joy Tsai [email protected] Katie Cebula [email protected] Sue Fletcher‑Watson sue.fletcher‑[email protected] 1
Moray House School of Education, St John’s Land, The University of Edinburgh, Holyrood Rd, Edinburgh EH8 8AQ, UK
2
The Patrick Wild Centre, Centre for Clinical Brain Sciences, The University of Edinburgh, Kennedy Tower, Edinburgh EH10 5HF, UK
Keywords Autism · Broader autism phenotype · Typically developing sibling · Adjustment · Cross-culture
Introduction Siblings of children with autism spectrum disorders (ASD) have often been found to be more susceptible to psychological maladjustment than siblings of typically developing children (Lovell and Wetherell 2016; Petalas et al. 2012; Walton and Ingersoll 2015; Griffith et al. 2014). In contrast, some research has found that typically developing sibling of children with autism (TD sibling) displayed better social competence or positive self-concept (Verte et al. 2003; Macks and Reeve 2007; Kaminsky and Dewey 2002) and others have found no difference in comparison to siblings of TD children or normative data (Tomeny et al. 2012; Quintero and McIntyre 2010; Rodgers et al. 2016; Dempsey et al. 2012). Several demographic variables have been identified as having an association with TD siblings’ adjustment, such as socioeconomic status, family size, gender and age (Kaminsky and Dewey 2002; Verte et al. 2003; Macks and Reeve 2007; Giallo and Gavidia-Payne 2006). Psychological variables that may moderate or mediate adjustment difficulties of siblings of children with ASD have also been studied, such as social support, impact of life events and coping strategies (Petalas et al. 2012; Hastings 2003; Ross and Cuskelly 2006). In particular, the severity of symptoms of the child with ASD and their challenging behaviour have consistently been found to be a predictor of TD siblings’ psychological well-being (Benson and Karlof 2008; Lyons et al. 2010; Meyer et al. 2011) and this may go some way to explaining the variability in results of studies examining sibling outcomes.
13
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Over recent years ASD family research has moved away from looking simply at whether siblings experience positive or negative outcomes, towards a more theoretical driven consideration of the pathways to such outcome (e.g. McHale et al. 2016). In particular, there has been a more integrated examination of genetic vulnerabilities and how they interact with environmental stressors to influence TD sibling adjustment (Petalas et al. 2012; Mohammadi and Zarafshan 2014; Meyer et al. 2011; Walton and Ingersoll 2015). The principal genetic vulnerability factor of interest in the present study is the broader autism phenotype (BAP). The BAP is a collection of behaviours and traits that are conceptually similar to the core ASD symptom domains, but are a sub-clinical manifestation of such traits (Folstein and Rutter 1977; Piven et al. 1997; Cruz et al. 2013). It has been estimated that between 12 and 20% of the non-autistic siblings of children with ASD display such traits (Rotatori and Deisinger 2015). Multiple studies have found that siblings of children with ASD are more likely to have subtle difficulties in communication (Ben-Yizhak et al. 2011; Gamliel et al. 2009), social interaction, and academic development (Constantino et al. 2006; Yoder et al. 2009) or to exhibit neurocognitive impairments (Dawson et al. 2002) compared to siblings of TD children. However, environmental influences will also play a role. For example, Barak-Levy et al. (2010) found that TD siblings of children with ASD participated less in extracurricular activities, and had poorer social relations, when compared to siblings of TD children. As suggested by the authors, whilst genetically-based traits may lead TD siblings to be more introverted and less active than other children, the presence of a child with ASD at home might also make it more difficult to develop social relations. Bauminger and Yirmiya (2001) proposed using a ‘diathesis-stress’ model for research with siblings of children with ASD. This model incorporates the influence of the genetic vulnerability (diathesis) and its interaction with environmental stress to impact on families of individuals with ASD. This model has been adopted in several sibling studies to date (Orsmond and Seltzer 2009; Petalas et al. 2012; Walton and Ingersoll 2015; Mohammadi and Zarafshan 2014). These have provided partial support for the diathesis-stress model, finding that environmental stressors (e.g. the presence of stressful life events, or symptom severity in the child with ASD) interacts with TD sibling BAP level to influence outcomes such as their emotional symptoms, adjustment outcome and sibling relationship. Such findings can inform support practices for the siblings of children with autism by highlighting relevant sibling traits which should be taken into account when providing support, as well as by identifying direct targets for intervention.
13
J Autism Dev Disord (2017) 47:2363–2377
However, while research has been gradually begun to identify the factors, such as BAP, that contribute to TD sibling adjustment, the majority of research to date has been based in Western settings. Specifically, the positive association between BAP levels and TD sibling adjustment difficulties reported in Western cultures (e.g. Pisula and Ziegart-Sadowska 2015; Petalas et al. 2012) has never been explored in Chinese populations, nor has the utility of the diathesis-stress model been tested in this culture. Societal perceptions of disability, interpretation of Western-developed concepts of adjustment, and parents’ perceptions of their child’s behaviour all vary between Chinese and Western cultures (Phinney et al. 2000; Tsai 2016). As cultural factors shape family experience (Sage and Jegatheesan 2010; Lin et al. 2011; Tsai 2016) the utility of the diathesisstress model might differ from one country to another. It is therefore important to explore the extent to which this model characterises sibling experience in Chinese as well as Western contexts in order to inform support practices in Chinese societies. One of the challenges in Western sibling diathesis-stress studies to date is determining the role that parental BAP plays. Previous research has partially supported the role of parents’ BAP traits as a genetic vulnerability factor within a diathesis-stress model. For example, Orsmond and Seltzer (2009) reported an interaction between parents’ BAP traits and an environmental stressor (sibling life events) to predict sibling depressive symptoms, but other interactions that they explored (e.g. parents’ BAP and behaviour problems in the child with autism) did not predict sibling outcomes. However, parental BAP traits might also contribute to apparent poorer sibling outcomes by creating measurement issues. For example BAP traits in parents of children with ASD might affect sensitivity to maladaptive behaviour, in turn influencing their perceptions and reporting of their children’s adjustment (Petalas et al. 2012; Orsmond and Seltzer 2009). To date, however, the relations between parents’ BAP level and how they evaluate their children’s behaviour have only been explored in Western research (e.g. Petalas et al. 2012). It has previously been reported that Chinese parents adopt higher standards of expected child behaviour than Western parents (Chao 1994; Shek and Chan 1999; Porter et al. 2005). However, Lau et al. (2013) notes that there appears to be a consistency in the manifestation of autistic traits across Chinese and Western studies. Overall, it is not clear whether BAP levels will affect parents’ reports of their child’s behaviour differently in the two cultures. This research seeks to fill existing gaps in our knowledge by investigating the role that genetic liability (BAP level) plays in sibling adjustment. Specifically, it explored how BAP level is associated with adjustment in TD siblings in the United Kingdom (UK) and Taiwan. It also explores
J Autism Dev Disord (2017) 47:2363–2377
the relations between parental BAP and sibling adjustment (employing both parental and self-report scores), in order to explore whether parental BAP appears to be related to sibling adjustment, or to the parent perceptions of sibling adjustment. The extent to which the diathesis-stress model provides a good explanation of factors associated with sibling adjustment in both Western and Chinese cultural settings was also investigated. Based on previous research, we predicted that TD siblings in both countries with higher level of BAP would show greater adjustment difficulties than those with lower levels of BAP. We also hypothesised that parents with higher BAP levels would report greater adjustment difficulty in their TD children than would parents with lower BAP levels, and aimed to explore whether this effect would differ across the two countries. Finally, we predicted that the diathesis-stress model would be moderately supported in the Western setting, with some significant interactions between BAP level and environmental stress predictive of sibling adjustment. The extent to which this model would provide a satisfactory framework in the Chinese setting was also explored.
Methods Participants The inclusion criteria for the study were (a) families with a child with ASD and another TD sibling between 7 and 18 years old living at home; (b) formal ASD diagnosis in the child with ASD, as indicated by parental report; (c) TD siblings and mothers had sufficient Chinese or English skills (as appropriate) to participate in the research. As the study was focused on the role of culture in sibling experiences, inclusion was restricted to families who self-identified as being of UK/Irish origin in the UK and of Chinese/ Taiwanese origin in Taiwan. Whilst the resultant samples do not then fully represent the ethnic diversity which exists within the two research settings, such criteria allowed for examination of the role of culture in sibling adjustment. Families were excluded if (a) the child with ASD did not have a formal diagnosis or was waiting for a diagnosis; (b) the participating siblings had a suspected ASD diagnosis. Potential sibling participants were not formally screened for inclusion in this respect, but project materials made inclusion criteria clear, and siblings were excluded if mothers indicated that an ASD diagnosis was suspected. Birth order and age have been found to relate to sibling adjustment (Stoneman 2005; Roeyers and Mycke 1995; Breslau 1982). For consistency, therefore, in families with more than one TD sibling, the one whose age was closest to that of the child with ASD was asked to participate.
2365
There were 89 and 85 mother-TD sibling dyads of questionnaires received from Taiwan and the UK respectively. However, if participants had not completed more than 20% of the whole research survey, their data were excluded from the analyses. This applied to 10.1% participants in Taiwan and 11.8% in the UK. The final sample included in the analysis was therefore 80 and 75 mother-TD sibling dyads from Taiwan and the UK respectively. All the mothers were biological mothers. The Taiwanese sample were 98.8% Taiwanese and 1.2% Chinese, while 95.9% of participants in the UK sample were British and 4.1% were Irish. The two cultural groups did not differ from each other in terms of the age and gender of the ASD and TD siblings, nor in the symptom severity of the children with ASD and the proportion of children falling into each diagnostic subgroup. Children with ASD in Taiwan had significantly higher rates of combined intellectual disability, while their UK counterparts had significantly higher rate of comorbid diagnoses. These findings may reflect differences which exist in clinical/diagnostic practice and how children’s behaviours are viewed between cultures (e.g. Norbury and Sparks 2013). Mothers in the UK also reporting significantly higher education levels, job positions and subjective wealth than the Taiwanese mothers (see Table 1). Procedure Ethical approval was obtained from the authors’ institution prior to commencement of the study. There were three major recruitment routes. Firstly, parents were contacted via organizations/schools/support groups (with additional ethical approval obtained as required) and secondly the study was publicized online direct to potential participants. Due to differences in standard research practice and in participant expectations in Taiwan and the UK, there was a third recruitment route in Taiwan via hospital and psychiatry clinics. Permission from the Institutional Review Board (IRB) was obtained in each hospital, and potential participant families were then contacted via their clinician. When expressions of interest were received from parents, it was ascertained that the family met the recruitment criteria, and one of the researchers spoke with the parents or TD siblings to clarify the inclusion criteria/research procedure if necessary. Participant families were supplied with parent and sibling project information and consent/assent sheets via post, email, social networking sites, or schools. Informed consent/assent was obtained from the parent and the TD sibling. Families were then sent two bound packs of questionnaires (one for the mother and the other for the TD sibling), each containing full instructions, and a stamped addressed envelope for the mother to return the completed questionnaires. TD siblings were provided a blank envelope to seal
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J Autism Dev Disord (2017) 47:2363–2377
Table 1 Parent and child characteristics of Taiwanese (TW) and the United Kingdom (UK) samples
Parental characteristics Relationship status Level of education Employment status Job description Subjective wealth Number of children Children’s characteristics ASD sib age in years TD sib age in years ASD and TD sib age difference ASD sib gender TD sib gender ASD sib diagnosis ASD severity (SRS T scores) ASD sib presence of ID ASD sib comorbid other diagnosis ASD sib type of school attended Study variables ASD sib severity (SRS T scores) Parent AQ scores TD sib AQ scores Life events Negative events numbers Negative events impact
TW sample (n = 80)
UK sample (n = 75)
Statistic
(% living with partner) (% university or above) (% full-time) (% professional/non-manual skilled) (% manage alright) Mean (SD) [range]
94.9% 35.4% 46.3% 44.9%
82.4% 68.9% 23.0% 79.1%
6.05* 19.1** 20.0*** 21.9**
49.3% 2.3 (0.5) [2–4]
72.2% 2.7 (0.8) [2–5]
26.4*** −3.29**
Mean (SD) [range] Mean (SD) [range] (ASD-TD) [range]
12.2 (3.6) [4.0–21.5] 12.7 (2.8) [7.2–18.0] −0.52 (3.3) [−8.1 to 10.7]
11.2 (3.5) [5.0-21.3] 12.7 (2.4) [8.6–17.7] −1.6 (3.5) [−9.9 to 6.0]
1.65 −0.05 1.82
(% male) (% male) (% ASD) Mean (SD) [range] (% yes) (% yes)
88.2% 41% 74.7% 78.8 (8.8) [55–90] 47.5% 18.9%
87.8% 37.3% 60.8% 79.9 (9.2) [55–90] 24% 45.9%
0.004 0.22 3.3 −0.78 22.7*** 12.3***
(% special education school)
16.5%
28.4%
30.5***
Mean (SD) [range]
78.8 (8.8) [55–90]
79.9 (9.2) [55–90]
−0.78
Mean (SD) [range] Mean (SD) [range]
17.8 (7.5) [5–37] 66.6 (21.5) [30–114]
12.9 (7.7) [2–42] 52.84 (33.6) [4–132]
3.96*** 2.97**
Mean (SD) [range] Mean (SD) [range]
3.7 (2.6) [0–9] 7.8 (5.4) [1–22]
4.6 (2.8) [0–11] 9.8 (6.6) [0–26]
−2.15* −1.99*
TD sib typically developing sibling, ASD sib children with ASD, ID intellectual disability, SRS social responsiveness scale, AQ autism spectrum quotient *p
ORIGINAL PAPER
The Role of the Broader Autism Phenotype and Environmental Stressors in the Adjustment of Siblings of Children with Autism Spectrum Disorders in Taiwan and the United Kingdom Hsiao‑Wei Joy Tsai1 · Katie Cebula1 · Sue Fletcher‑Watson2
Published online: 13 May 2017 © The Author(s) 2017. This article is an open access publication
Abstract The influence of the broader autism phenotype (BAP) on the adjustment of siblings of children with autism has previously been researched mainly in Western cultures. The present research evaluated a diathesis-stress model of sibling adjustment using a questionnaire study including 80 and 75 mother-typically developing sibling dyads in Taiwan and the United Kingdom (UK). UK siblings reported elevated adjustment difficulties compared to the Taiwanese sample and to normative data. Whilst higher BAP levels were generally associated with greater adjustment difficulties, differences were found across cultures and respondents. Although significant diathesis-stress interactions were found, these were in the opposite direction from those predicted by the model, and differed across cultural settings. Implications for culturally-sensitive sibling support are considered.
This research formed part of Hsiao-Wei Joy Tsai’s doctoral dissertation in the Moray House School of Education, the University of Edinburgh, UK. * Hsiao‑Wei Joy Tsai [email protected] Katie Cebula [email protected] Sue Fletcher‑Watson sue.fletcher‑[email protected] 1
Moray House School of Education, St John’s Land, The University of Edinburgh, Holyrood Rd, Edinburgh EH8 8AQ, UK
2
The Patrick Wild Centre, Centre for Clinical Brain Sciences, The University of Edinburgh, Kennedy Tower, Edinburgh EH10 5HF, UK
Keywords Autism · Broader autism phenotype · Typically developing sibling · Adjustment · Cross-culture
Introduction Siblings of children with autism spectrum disorders (ASD) have often been found to be more susceptible to psychological maladjustment than siblings of typically developing children (Lovell and Wetherell 2016; Petalas et al. 2012; Walton and Ingersoll 2015; Griffith et al. 2014). In contrast, some research has found that typically developing sibling of children with autism (TD sibling) displayed better social competence or positive self-concept (Verte et al. 2003; Macks and Reeve 2007; Kaminsky and Dewey 2002) and others have found no difference in comparison to siblings of TD children or normative data (Tomeny et al. 2012; Quintero and McIntyre 2010; Rodgers et al. 2016; Dempsey et al. 2012). Several demographic variables have been identified as having an association with TD siblings’ adjustment, such as socioeconomic status, family size, gender and age (Kaminsky and Dewey 2002; Verte et al. 2003; Macks and Reeve 2007; Giallo and Gavidia-Payne 2006). Psychological variables that may moderate or mediate adjustment difficulties of siblings of children with ASD have also been studied, such as social support, impact of life events and coping strategies (Petalas et al. 2012; Hastings 2003; Ross and Cuskelly 2006). In particular, the severity of symptoms of the child with ASD and their challenging behaviour have consistently been found to be a predictor of TD siblings’ psychological well-being (Benson and Karlof 2008; Lyons et al. 2010; Meyer et al. 2011) and this may go some way to explaining the variability in results of studies examining sibling outcomes.
13
Vol.:(0123456789)
2364
Over recent years ASD family research has moved away from looking simply at whether siblings experience positive or negative outcomes, towards a more theoretical driven consideration of the pathways to such outcome (e.g. McHale et al. 2016). In particular, there has been a more integrated examination of genetic vulnerabilities and how they interact with environmental stressors to influence TD sibling adjustment (Petalas et al. 2012; Mohammadi and Zarafshan 2014; Meyer et al. 2011; Walton and Ingersoll 2015). The principal genetic vulnerability factor of interest in the present study is the broader autism phenotype (BAP). The BAP is a collection of behaviours and traits that are conceptually similar to the core ASD symptom domains, but are a sub-clinical manifestation of such traits (Folstein and Rutter 1977; Piven et al. 1997; Cruz et al. 2013). It has been estimated that between 12 and 20% of the non-autistic siblings of children with ASD display such traits (Rotatori and Deisinger 2015). Multiple studies have found that siblings of children with ASD are more likely to have subtle difficulties in communication (Ben-Yizhak et al. 2011; Gamliel et al. 2009), social interaction, and academic development (Constantino et al. 2006; Yoder et al. 2009) or to exhibit neurocognitive impairments (Dawson et al. 2002) compared to siblings of TD children. However, environmental influences will also play a role. For example, Barak-Levy et al. (2010) found that TD siblings of children with ASD participated less in extracurricular activities, and had poorer social relations, when compared to siblings of TD children. As suggested by the authors, whilst genetically-based traits may lead TD siblings to be more introverted and less active than other children, the presence of a child with ASD at home might also make it more difficult to develop social relations. Bauminger and Yirmiya (2001) proposed using a ‘diathesis-stress’ model for research with siblings of children with ASD. This model incorporates the influence of the genetic vulnerability (diathesis) and its interaction with environmental stress to impact on families of individuals with ASD. This model has been adopted in several sibling studies to date (Orsmond and Seltzer 2009; Petalas et al. 2012; Walton and Ingersoll 2015; Mohammadi and Zarafshan 2014). These have provided partial support for the diathesis-stress model, finding that environmental stressors (e.g. the presence of stressful life events, or symptom severity in the child with ASD) interacts with TD sibling BAP level to influence outcomes such as their emotional symptoms, adjustment outcome and sibling relationship. Such findings can inform support practices for the siblings of children with autism by highlighting relevant sibling traits which should be taken into account when providing support, as well as by identifying direct targets for intervention.
13
J Autism Dev Disord (2017) 47:2363–2377
However, while research has been gradually begun to identify the factors, such as BAP, that contribute to TD sibling adjustment, the majority of research to date has been based in Western settings. Specifically, the positive association between BAP levels and TD sibling adjustment difficulties reported in Western cultures (e.g. Pisula and Ziegart-Sadowska 2015; Petalas et al. 2012) has never been explored in Chinese populations, nor has the utility of the diathesis-stress model been tested in this culture. Societal perceptions of disability, interpretation of Western-developed concepts of adjustment, and parents’ perceptions of their child’s behaviour all vary between Chinese and Western cultures (Phinney et al. 2000; Tsai 2016). As cultural factors shape family experience (Sage and Jegatheesan 2010; Lin et al. 2011; Tsai 2016) the utility of the diathesisstress model might differ from one country to another. It is therefore important to explore the extent to which this model characterises sibling experience in Chinese as well as Western contexts in order to inform support practices in Chinese societies. One of the challenges in Western sibling diathesis-stress studies to date is determining the role that parental BAP plays. Previous research has partially supported the role of parents’ BAP traits as a genetic vulnerability factor within a diathesis-stress model. For example, Orsmond and Seltzer (2009) reported an interaction between parents’ BAP traits and an environmental stressor (sibling life events) to predict sibling depressive symptoms, but other interactions that they explored (e.g. parents’ BAP and behaviour problems in the child with autism) did not predict sibling outcomes. However, parental BAP traits might also contribute to apparent poorer sibling outcomes by creating measurement issues. For example BAP traits in parents of children with ASD might affect sensitivity to maladaptive behaviour, in turn influencing their perceptions and reporting of their children’s adjustment (Petalas et al. 2012; Orsmond and Seltzer 2009). To date, however, the relations between parents’ BAP level and how they evaluate their children’s behaviour have only been explored in Western research (e.g. Petalas et al. 2012). It has previously been reported that Chinese parents adopt higher standards of expected child behaviour than Western parents (Chao 1994; Shek and Chan 1999; Porter et al. 2005). However, Lau et al. (2013) notes that there appears to be a consistency in the manifestation of autistic traits across Chinese and Western studies. Overall, it is not clear whether BAP levels will affect parents’ reports of their child’s behaviour differently in the two cultures. This research seeks to fill existing gaps in our knowledge by investigating the role that genetic liability (BAP level) plays in sibling adjustment. Specifically, it explored how BAP level is associated with adjustment in TD siblings in the United Kingdom (UK) and Taiwan. It also explores
J Autism Dev Disord (2017) 47:2363–2377
the relations between parental BAP and sibling adjustment (employing both parental and self-report scores), in order to explore whether parental BAP appears to be related to sibling adjustment, or to the parent perceptions of sibling adjustment. The extent to which the diathesis-stress model provides a good explanation of factors associated with sibling adjustment in both Western and Chinese cultural settings was also investigated. Based on previous research, we predicted that TD siblings in both countries with higher level of BAP would show greater adjustment difficulties than those with lower levels of BAP. We also hypothesised that parents with higher BAP levels would report greater adjustment difficulty in their TD children than would parents with lower BAP levels, and aimed to explore whether this effect would differ across the two countries. Finally, we predicted that the diathesis-stress model would be moderately supported in the Western setting, with some significant interactions between BAP level and environmental stress predictive of sibling adjustment. The extent to which this model would provide a satisfactory framework in the Chinese setting was also explored.
Methods Participants The inclusion criteria for the study were (a) families with a child with ASD and another TD sibling between 7 and 18 years old living at home; (b) formal ASD diagnosis in the child with ASD, as indicated by parental report; (c) TD siblings and mothers had sufficient Chinese or English skills (as appropriate) to participate in the research. As the study was focused on the role of culture in sibling experiences, inclusion was restricted to families who self-identified as being of UK/Irish origin in the UK and of Chinese/ Taiwanese origin in Taiwan. Whilst the resultant samples do not then fully represent the ethnic diversity which exists within the two research settings, such criteria allowed for examination of the role of culture in sibling adjustment. Families were excluded if (a) the child with ASD did not have a formal diagnosis or was waiting for a diagnosis; (b) the participating siblings had a suspected ASD diagnosis. Potential sibling participants were not formally screened for inclusion in this respect, but project materials made inclusion criteria clear, and siblings were excluded if mothers indicated that an ASD diagnosis was suspected. Birth order and age have been found to relate to sibling adjustment (Stoneman 2005; Roeyers and Mycke 1995; Breslau 1982). For consistency, therefore, in families with more than one TD sibling, the one whose age was closest to that of the child with ASD was asked to participate.
2365
There were 89 and 85 mother-TD sibling dyads of questionnaires received from Taiwan and the UK respectively. However, if participants had not completed more than 20% of the whole research survey, their data were excluded from the analyses. This applied to 10.1% participants in Taiwan and 11.8% in the UK. The final sample included in the analysis was therefore 80 and 75 mother-TD sibling dyads from Taiwan and the UK respectively. All the mothers were biological mothers. The Taiwanese sample were 98.8% Taiwanese and 1.2% Chinese, while 95.9% of participants in the UK sample were British and 4.1% were Irish. The two cultural groups did not differ from each other in terms of the age and gender of the ASD and TD siblings, nor in the symptom severity of the children with ASD and the proportion of children falling into each diagnostic subgroup. Children with ASD in Taiwan had significantly higher rates of combined intellectual disability, while their UK counterparts had significantly higher rate of comorbid diagnoses. These findings may reflect differences which exist in clinical/diagnostic practice and how children’s behaviours are viewed between cultures (e.g. Norbury and Sparks 2013). Mothers in the UK also reporting significantly higher education levels, job positions and subjective wealth than the Taiwanese mothers (see Table 1). Procedure Ethical approval was obtained from the authors’ institution prior to commencement of the study. There were three major recruitment routes. Firstly, parents were contacted via organizations/schools/support groups (with additional ethical approval obtained as required) and secondly the study was publicized online direct to potential participants. Due to differences in standard research practice and in participant expectations in Taiwan and the UK, there was a third recruitment route in Taiwan via hospital and psychiatry clinics. Permission from the Institutional Review Board (IRB) was obtained in each hospital, and potential participant families were then contacted via their clinician. When expressions of interest were received from parents, it was ascertained that the family met the recruitment criteria, and one of the researchers spoke with the parents or TD siblings to clarify the inclusion criteria/research procedure if necessary. Participant families were supplied with parent and sibling project information and consent/assent sheets via post, email, social networking sites, or schools. Informed consent/assent was obtained from the parent and the TD sibling. Families were then sent two bound packs of questionnaires (one for the mother and the other for the TD sibling), each containing full instructions, and a stamped addressed envelope for the mother to return the completed questionnaires. TD siblings were provided a blank envelope to seal
13
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J Autism Dev Disord (2017) 47:2363–2377
Table 1 Parent and child characteristics of Taiwanese (TW) and the United Kingdom (UK) samples
Parental characteristics Relationship status Level of education Employment status Job description Subjective wealth Number of children Children’s characteristics ASD sib age in years TD sib age in years ASD and TD sib age difference ASD sib gender TD sib gender ASD sib diagnosis ASD severity (SRS T scores) ASD sib presence of ID ASD sib comorbid other diagnosis ASD sib type of school attended Study variables ASD sib severity (SRS T scores) Parent AQ scores TD sib AQ scores Life events Negative events numbers Negative events impact
TW sample (n = 80)
UK sample (n = 75)
Statistic
(% living with partner) (% university or above) (% full-time) (% professional/non-manual skilled) (% manage alright) Mean (SD) [range]
94.9% 35.4% 46.3% 44.9%
82.4% 68.9% 23.0% 79.1%
6.05* 19.1** 20.0*** 21.9**
49.3% 2.3 (0.5) [2–4]
72.2% 2.7 (0.8) [2–5]
26.4*** −3.29**
Mean (SD) [range] Mean (SD) [range] (ASD-TD) [range]
12.2 (3.6) [4.0–21.5] 12.7 (2.8) [7.2–18.0] −0.52 (3.3) [−8.1 to 10.7]
11.2 (3.5) [5.0-21.3] 12.7 (2.4) [8.6–17.7] −1.6 (3.5) [−9.9 to 6.0]
1.65 −0.05 1.82
(% male) (% male) (% ASD) Mean (SD) [range] (% yes) (% yes)
88.2% 41% 74.7% 78.8 (8.8) [55–90] 47.5% 18.9%
87.8% 37.3% 60.8% 79.9 (9.2) [55–90] 24% 45.9%
0.004 0.22 3.3 −0.78 22.7*** 12.3***
(% special education school)
16.5%
28.4%
30.5***
Mean (SD) [range]
78.8 (8.8) [55–90]
79.9 (9.2) [55–90]
−0.78
Mean (SD) [range] Mean (SD) [range]
17.8 (7.5) [5–37] 66.6 (21.5) [30–114]
12.9 (7.7) [2–42] 52.84 (33.6) [4–132]
3.96*** 2.97**
Mean (SD) [range] Mean (SD) [range]
3.7 (2.6) [0–9] 7.8 (5.4) [1–22]
4.6 (2.8) [0–11] 9.8 (6.6) [0–26]
−2.15* −1.99*
TD sib typically developing sibling, ASD sib children with ASD, ID intellectual disability, SRS social responsiveness scale, AQ autism spectrum quotient *p
