AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

EAAIDD DOI: 10.1352/1944-7558-119.1.49

Adaptive Behavior and Problem Behavior in Young Children With Williams Syndrome Laura J. Hahn, Deborah J. Fidler, and Susan L. Hepburn

Abstract The present study compares the adaptive behavior profile of 18 young children with Williams syndrome (WS) and a developmentally matched group of 19 children with developmental disabilities and examines the relationship between adaptive behavior and problem behaviors in WS. Parents completed the Vineland Adaptive Behavioral Scales— Interview edition and the Developmental Behavior Checklist—Primary Caregiver version (WS only). Children with WS had higher adaptive communication scores than children with other developmental disabilities. Children with WS demonstrated relative strengths in adaptive communication and socialization, coupled with relative weaknesses in daily living. Adaptive communication and socialization were negatively associated with problem behaviors in social relating in WS. Key Words: Williams syndrome; adaptive behavior; problem behavior

Williams syndrome (WS) is a neurogenetic disorder (Bellugi, Lichtenberger, Jones, Lai, & St. George, 2001) with an incidence rate of one in 7,500 (Strømme, Bjørnstad, & Ramstad, 2002). WS is caused by a microdeletion on chromosome 7 (Ewart et al., 1993), which leads to mild to moderate cognitive and developmental delays in most cases (Bellugi & St. George, 2001). Behavioral research on WS over the past several decades has focused on characterizing patterns of developmental strength and weakness in this population (for a full review see Bellugi et al., 2001; Dykens, 2003b; Martens, Wilson, & Reutens, 2008; Mervis & Klein-Tasman, 2000). Areas of relative strength include some aspects of expressive language development, social interest and engagement, facial recognition, and auditory rote memory (Bellugi & St. George, 2001, Dykens, 2003b; Mervis & Klein-Tasman, 2000). Areas of relative weakness include visuospatial cognition and motor skills, which includes impairments in visuomotor construction (Bellugi & St. George, 2001; Dykens, 2003b; Mervis & Klein-Tasman, 2000). Individuals with WS also have a distinct personality profile characterized by hypersociaL. J. Hahn, D. J. Fidler, and S. L. Hepburn

bility, eagerness to engage with others, and emotional attunement (Gosch & Pankau, 1997; Ja¨rvinen-Pasley et al., 2008; Jones et al., 2001; Mervis & Klein-Tasman, 2000; Plesa-Skwerer, Faja, Schofield, Verbalis, & Tager-Flusberg, 2006; Tager-Flusberg, Plesa-Skwerer, & Joseph, 2006). However, this personality profile is coupled with maladaptive behaviors, such as high levels of anxiety and fear, which may impact social adaptive functioning (Bellugi et al., 2001; Dykens et al., 2000; Hodapp & DesJardin, 2002; Mervis, 1999). Problem behaviors have been the focus of numerous studies of individuals with WS, with reports of elevated levels of anxiety and fears, attention problems, distractibility, impulsivity, low frustration tolerance, poor adaptability (e.g., difficultly in adjusting to new situations, difficulty following directions, etc.), and atypical activity (e.g., hyperactivity/overactivity, restlessness, etc.; Davies, Udwin, & Howlin, 1998; Dilts, Morris, & Leonard; 1990; Dykens, 2003a; Dykens & Rosner, 1999; Einfeld, Tonge, & Florio, 1997; Einfeld, Tonge, & Rees, 2001; Gosch & Pankau, 1997; Perez-Garcia, Garnero, Gallastegui, Perez-Jurado, & Brun-Gasca, 2011; Pober & Dykens, 1996; 49

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

Tomc, Williamson, & Pauli, 1990; Udwin, 1990). The pattern of maladaptive behavior associated with WS may influence the development of adaptive behavior in children with WS and interfere with their ‘‘ability to meet daily living responsibilities and respond to the needs of others, including conceptual, practical, and social skills that people need to function in their everyday lives’’ (Ditterline & Oakland, 2009, p. 45).

Adaptive Behavior Adaptive behavior in WS has received a small amount of research attention, and existing studies have primarily focused on older children and adults (Howlin, Elison, Udwin, & Stinton, 2010). To assess adaptive behavior, most of these studies have used the Vineland Adaptive Behavior Scales (VABS; Sparrow, Balla, & Cicchetti, 1984) or its predecessor the Vineland Social Maturity Scale (Doll, 1965), both of which assess four domains of adaptive behavior: communication, socialization, daily living, and motor skills (Doll, 1965; Sparrow et al., 1984). Existing studies to date suggest that overall adaptive functioning in children and adults with WS, while delayed, is generally congruent with overall developmental status (Davies, Howlin, & Udwin, 1997; Gosch & Pankau, 1994; Greer, Brown, Pai, Choudry, & Klein, 1997; Mervis, Klein-Tasman, & Mastin, 2001) and continues to improve with age, but remains delayed when compared to typically developing peers (Howlin et al., 2010). However, while overall adaptive functioning in individuals with WS is congruent with developmental status, previous studies report patterns of strength and challenge within the various domains of the VABS (Cherniske et al., 2004; Davies et al., 1997; Greer et al., 1997; Howlin, Davies, & Udwin, 1998; Howlin et al., 2010; Mervis et al., 2001). During middle childhood in WS, the socialization and communication domains of the VABS appear to be areas of strength relative to daily living (Greer et al., 1997; Mervis et al., 2001). Mervis et al. (2001) also suggest that motor skills are an area of relative weakness for children with WS under the age of six. Based on existing findings, it is unclear whether motor skills are an area of relative weakness at all ages or only early in development (Gosch & Pankau, 1994; Mervis et al., 2001). Furthermore, it is unclear whether 50

EAAIDD DOI: 10.1352/1944-7558-119.1.49

performances on the motor skills domain of the VABS are related to the phenotypic impairments in fine motor skills and visuomotor construction that have been observed in WS (Bellugi & St. George, 2001; Dykens, 2003b; Mervis & KleinTasman, 2000). Studies to date have reported a somewhat different pattern of adaptive strengths and weaknesses in adults with WS. Socialization skills are reported to be an area of relative strength in adults with WS (Cherniske et al., 2004; Howlin et al., 1998); however, both Howlin et al. (1998) and Cherniske et al. (2004) found relative weakness on the communication domain of the VABS in their samples of adults with WS. This finding is further supported by a cross-sectional and longitudinal exploration of adaptive behavior in a sample of adults with WS between the ages of 19 and 55 conducted by Howlin et al. (2010), which suggested that performance within the communication domain tends to be consistently lower than the other domains of the VABS in adulthood. In a recent study, Di Nuovo and Buono (2011) reported a somewhat different profile of adaptive functioning in their sample of 7 to 30 year olds with WS. In this sample, individuals with WS not only had consistently lower performance on the communication domain, but also performance on the socialization domain was lower than performance on the daily living and motor skills domains (Di Nuovo & Buono, 2011). Although the finding of lower performance on the communication domain is supported by other studies on adaptive behavior in WS (Cherniske et al., 2004; Howlin et al., 1998; Howlin et al., 2010), none of the other existing studies on adaptive behavior in WS have identified socialization to be an area of weakness, and no other studies have reported stronger daily living skills than socialization skills. Taken together, there appears to be a shift in parent/caregiver report of adaptive communication skills from childhood to adulthood in individuals with WS. In the context of these developmentally contingent findings, there is little information regarding the early emergence of adaptive skills in children with WS younger than 5 years. Studying the early development of adaptive skills in WS may provide insight into whether patterns of strengths and weakness observed in childhood show continuity or discontinuity over the lifespan. Adaptive and Problem Behavior in WS

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

Developmental Considerations Previous studies on adaptive behavior in WS have demonstrated that higher general cognitive abilities in middle childhood, adolescence, and adulthood are associated with higher standard scores on the communication, daily living, and socialization domains of the VABS (Davies et al., 1997; Howlin et al., 2010; Mervis et al., 2001). Only one existing study has discussed the potential influence of developmental functioning on the performance of children with WS on the VABS. Mervis et al. (2001) suggest that performance on the motor skills and daily living domains may be influenced by difficulties in visuospatial construction, while performance on the socialization domain may be influenced by strengths in verbal and auditory rote memory. Mervis et al. (2001) further suggest that performance on the communication domain of the VABS may be influenced by the relative strengths in verbal abilities associated with WS, but this suggested influence does not account for the complex language profile associated with WS during early childhood. Despite the strengths that have been described in some aspects of expressive language (Bellugi & St. George, 2001, Dykens, 2003b; Mervis & Klein-Tasman, 2000), these strengths in expressive language are not evident during early childhood (Bellugi et al., 2001). Further, overall language development in children with WS is delayed (Jarrold, Baddeley, & Hewes, 1998; Mervis & Klein-Tasman, 2000; SignerHarris, Bellugi, Bates, Jones, & Rossen, 1997). Therefore, it is unclear whether the delays in language skills observed in early childhood will influence the development of adaptive communication in children with WS.

Relationship Between Problem Behaviors and Adaptive Behavior Despite the evidence for distinct patterns of maladaptive behavior in individuals with WS, the relationship between problem behavior and adaptive behavior has received little research attention in this population (Di Nuovo & Buono, 2011). In one of the few examinations of this connection in WS, Di Nuovo and Buono (2011) studied the relationship between performance on the four domains of the VABS and the global Maladaptive Behavior Score of the VABS in adults with WS (Sparrow et al., 1984). Increased L. J. Hahn, D. J. Fidler, and S. L. Hepburn

EAAIDD DOI: 10.1352/1944-7558-119.1.49

rates of problem behaviors were associated with lower levels of adaptive functioning on the communication, socialization, and daily living domains of the VABS (Di Nuovo & Buono, 2011). This study is an important first step in examining the question of whether adaptation to daily life in WS may be compromised because of problem behaviors that interfere with the foundational skills for social and communicative functioning (i.e., making friends, adapting to new situations, following directions). While the relationship between adaptive behavior and problem behavior has received little research attention in individuals with WS, this relationship has been explored in other individuals with neurogenetic disorders and developmental disabilities. Results of these studies provide mixed conclusions on the nature of this relationship. One study of 4 to 18 year olds with developmental disabilities suggests that children with higher levels of problem behavior have lower adaptive functioning (de Bildt, Sytema, Kraijer, Sparrow, & Minderaa, 2005). Di Nuovo and Buono (2011) found that in children and adults with Fragile X syndrome, Down syndrome, Prader-Willi syndrome, and Angelman syndrome, there was a negative correlation between when maladaptive behavior and adaptive behavior. In contrast, a study of children between the ages of two and 18 with Fragile X syndrome found that there was no significant relationship between maladaptive and adaptive behaviors (Fisch et al., 1999). Similarly, in a study of children with Smith-Magenis syndrome between the ages of 2 and 12 years, no significant association between maladaptive and adaptive behaviors was observed (Martin, Wolters, & Smith, 2006). Taken together, it seems that for some groups of children with developmental disabilities, there is evidence of a relationship between adaptive behavior and behavior problems. However, more research is needed to fully explore this relationship in these populations.

Present Study The purpose of the present study is to describe the emerging adaptive behavior profile of young children with WS (under the age of five) and to examine associations with problem behaviors, which may influence skill development. Specifically, this study seeks to investigate whether areas of distinct strength and challenge in adaptive 51

EAAIDD DOI: 10.1352/1944-7558-119.1.49

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

functioning can be detected during early childhood in WS, and whether this profile differs from the patterns of strength and challenge observed in children with other developmental disabilities. In addition, the present study also examines the relatively unexplored question of how specific problem behaviors relate to day-to-day functioning in young children with WS. Findings from this study will provide insight into the issue of continuity and discontinuity within adaptive behavior skills across the lifespan in WS.

Method Participants Participants were 18 children with a confirmed diagnosis of WS and 19 chronological age and developmentally matched children with other developmental disabilities (DD; idiopathic DD 5 6, Down syndrome 5 5, fragile X syndrome without autism 5 3, Smith-Magenis syndrome 5 1, velocardiofacial syndrome 5 1, Cochayne syndrome 5 1, Sturge-Webber 5 1, and speech delays 5 1). Children with WS had a mean chronological age of 47.61 months (see Table 1 for developmental and demographic information), a mean visual reception raw score of 28.33, and a mean receptive language raw score of 25.33. Children with DD had a mean age of 45.68 months, a mean visual reception score of 28.16, and a mean receptive language raw score of 25.05. Groups were equated on receptive abilities as measured by the visual reception and receptive language domain raw scores of the Mullen Scales of Early Learning (MSEL, Mullen, 1995). Using these two domains for matching helped to avoid the confounds of mental age composites that frequently include measures of expressive language and fine motor skills, two areas with distinct profiles in children with WS (Bellugi et al., 2001; Bellugi & St. George, 2001; Dilts et al., 1990; Dykens, 2003b; Mervis & Klein-Tasman, 2000; Udwin & Yule, 1991). The phenotypic characteristics of strengths in some aspects of language development and impaired fine motor skills in children with WS make overall verbal ability and nonverbal ability potentially confounded measures of developmental level for children with WS (for a discussion of these concerns see Mervis et al., 2000). Table 2 presents the means, standard deviations, and range of raw domain scores for children 52

with WS and children with DD on the MSEL. Raw scores were used because they provide a better approximation of developmental level by reducing the floor effects associated with standard scores (Mervis & Klein-Tasman, 2004). No statistically significant differences emerged between the two groups for chronological age, t(35) 5 0.44, p 5 .92, MSEL visual reception, t(32) 5 0.10, p 5 .92, and MSEL receptive language, t(32) 5 0.12, p 5 .91. P values on the matching variables were greater than .50, as per Mervis et al. (Mervis & Klein-Tasman, 2004; Mervis & Robinson, 2003). It is important to note that children with WS and children with DD did significantly differ on MSEL fine motor raw scores, t(32) 5 22.02, p 5 .05, but not on MSEL Expressive Language raw scores, t(32) 5 1.32 , p 5 .20. For both groups, there was almost an equal gender split (WS group 5 55.6%; DD group 5 52.6%) and participants were predominantly white (WS group 5 94.7%; DD group 5 73.7%). For children with WS, annual family incomes ranged from less than $10,000 to $60,000 and for children with DD annual family incomes were between $20,000 and $60,000. Of mothers of children with WS, 17.6% had a high school diploma or less, 16.7% attended some college, 38.9% were college graduates, and 16.7% had post-graduate training. Of mothers of children with DD, 21.1% were high school graduates, 15.8% attended some college, 10.5% were college graduates, and 31.6% had post-graduate training.

Procedure Participants were recruited as part of two larger studies. One study was designed to examine and characterize the early emergence of the WS behavioral phenotype and the second study was designed to longitudinally examine the developing behavioral phenotypes of children with Down syndrome, fragile X syndrome, and autism. Participants were recruited from the Autism and Developmental Disabilities Research Groups of JFK Partners, the University of Colorado School of Medicine, and parent support groups (e.g., Williams Syndrome Association; Mile High Down Syndrome Association; Rocky Mountain Chapter of the Williams Syndrome Association; Mile High Down Syndrome Association; Wyoming Down Syndrome Association). The test battery was administered during laboratory visits and at a national conference Adaptive and Problem Behavior in WS

EAAIDD DOI: 10.1352/1944-7558-119.1.49

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

Table 1 Participant Characteristics Williams syndrome Characteristic

Developmental disabilities

M/%

SD

M/%

SD

CA at Vineland (in months) Child gender (% male)

47.61 55.6

14.46

45.68 52.6

12.07

Child ethnicity (%) White Hispanic Biracial Unknown/Choose not to respond

94.4 5.6 -

63.2 10.5 5.3 21

Some high school High school graduate Some college College graduate Post-graduate training Unknown/Choose not to respond

5.6 16.7 16.7 38.9 16.7 5.6

21.1 15.8 10.5 31.6 21.1

Income (%) Less than $10,000 $10,000–$20,000 $20,000–$30,000 $30,000–$40,000 $40,000–$50,000 $50,000–$60,000 Unknown/Choose not to respond

5.6 5.6 5.6 11.1 61.1 11.1

15.8 26.3 36.8 21.1

Maternal education (%)

with two examiners. All of the examiners were master’s or doctoral level researchers with several years of experience working with children with developmental disabilities. All assessments were counterbalanced and administered in at least two visits in order to maintain participant engagement and to reduce fatigue.

Measures The present study reports findings based on the following measures: Child information sheet. This child information sheet was created for the purpose of this study to collect basic child and family demographic information from parents. Mullen Scales of Early Learning (Mullen, 1995). The Mullen Scales of Early Learning (MSEL) is a standardized observational developmental assessment for children from 3 to 68 months. T scores are calculated for the five L. J. Hahn, D. J. Fidler, and S. L. Hepburn

domains (i.e., gross motor, fine motor, visual reception, expressive language, and receptive language) and an overall standard score that reflects an estimate of overall developmental functioning (Mullen, 1995). The MSEL has strong concurrent validly with other well-known developmental tests designed for young children (e.g., Bayley Scales of Infant Development, Bayley, 1993, Peabody Developmental Motor Scales, Folio & Fewell, 1983, Birth to Three Developmental Scale, Dodson & Bangs, 1979). Content validity, construct validity, and predictive validity have also been established (Mullen, 1995). Further, the MSEL has strong internal consistency coefficients (.83–.95), test–retest reliability coefficients (.82–.85), and interrater reliability coefficients (.91–.99; Mullen, 1995). Vineland Adaptive Behavior Scales—Interview Edition, Survey Form (Sparrow et al., 1984). The Vineland Adaptive Behavior Scales 53

EAAIDD DOI: 10.1352/1944-7558-119.1.49

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

Table 2 Means, Standard Deviations, and Ranges for the Mullen Scales of Early Learning Domains Raw Scores Williams syndrome Domain Visual reception raw score Fine motor raw score Receptive language raw score Expressive language raw score

M

SD

Range

M

SD

Range

28.33 23.13 25.33 27.33

5.38 5.46 8.56 8.61

16–41 11–31 5–38 9–38

28.16 26.68 25.05 23.58

5.11 4.78 5.64 7.95

17–37 17–38 12–33 7–35

(VABS) is a standardized parent interview developed to assess the personal and social functioning of individuals from birth through adulthood (Sparrow et al., 1984). There are four domains of behavior assessed by the VABS: socialization, communication, daily living, and motor skills. However, the motor skills domain is only administered to children under the age of six. In the present study, all of the participants were administered the motor skills domain. The survey form includes 297 items, which are administered in a semistructured, conventional manner. The survey form takes between 20 and 60 min to complete. Scoring is based on a 3-point Likert scale (never, sometimes/partially, or usually). Items may also be coded as ‘‘N,’’ never has had the opportunity to perform the activity and ‘‘DK,’’ for does not know if the child has performed the activity. Construct, content, and criterion validity have been established for the VABS (Sparrow et al., 1984). Overall the internal consistency of the VABS is satisfactory. The splithalf coefficients for the adaptive behavior composite and domains all range from .70s to .90s. Test–retest reliability coefficients for the survey form are generally good to excellent for the Adaptive Behavior Composite (low .80s to mid.90s) with most of the domains also in the good to excellent range. Interrater reliability coefficients for the domains are generally in the good to excellent range and in the moderately strong range (.70s to .80s) for the adaptive behavior composite (Sparrow et al., 1984). Developmental Behavior Checklist—Primary Caregiver version (Einfeld & Tonge, 1992; 2002). The Developmental Behavior Checklist—Primary Caregiver version (DBC-P) is a 96-item checklist that assesses a wide range of behavioral and emotional disturbances in children from 4 to 18 years with developmental and intellectual disabilities (Einfeld & Tonge, 1992; 2002). There are five subscales for the DBC: 54

Developmental disabilities

disruptive/antisocial behavior (e.g., has temper tantrums, lacks self-confidence), self-absorbed (e.g., aloof, in his/her own world; preoccupied with one or two interests), communication disturbance (e.g., confuses the use of pronouns, gets obsessed with an idea or activity), anxiety (e.g., distressed about being alone, fears particular things or situations), and social relating (e.g., appears depressed, downcast, or unhappy; doesn’t respond to others’ feelings). These subscales can be combined to calculate the total behavior problem score, which is an overall measure of behavioral and emotional problems. An important feature of the DBC-P is that it provides norms based on IQ categories. Scoring is based on a 3-point Likert scale (‘‘not true as far as you know,’’ ‘‘somewhat or sometimes true,’’ ‘‘very true or often true’’). The DBC-P has established high test–retest reliability, high interrater reliability between parents (.80), and high internal consistency (.94). Also, the DBC-P has high criterion validity and is highly correlated with the AAMD Behavior Scales (.86; Lambert & Windmiller, 1981) and the Scales of Independent Behavior (.70; Bruininks, Woodcock, Weatherman, & Hill, 1984). In the present study, DBC-P data were available only for the WS group. Therefore, a comparison could not be made between children with WS and children with DD on rates of problem behaviors.

Results Adaptive Behavior For the overall comparison of performance on the VABS between the WS and the DD groups a oneway multivariate analysis of variance (MANOVA) was conducted. MANOVA results indicated significant differences between the two groups and the four domains of adaptive behavior, Wilks’s L 5 .75, F(4, 32) 5 2.65, p 5 .05, g2 5 Adaptive and Problem Behavior in WS

EAAIDD DOI: 10.1352/1944-7558-119.1.49

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

.25; see Table 3 for means and standard deviations. Follow up univariate analysis of variance (ANOVA) indicated a significant difference between groups for the communication domain, F 5 (1, 35) 5 4.32, p 5 .05, g2 5 .11. Subsequent post-hoc independent samples t tests indicated that children in the WS group had higher mean performances on the VABS communication domain (M 5 74.44) when compared to children in the DD group (M 5 20.21 months), t(35) 5 2.08, p 5 .05. A repeated measures ANOVA was performed to further examine whether performance on one of the communication subdomains (e.g., receptive, expressive, or written communication) in children with WS was contributing more to overall performance on the communication domain. For these analyses, raw scores for the communication subdomains were used because standard scores are not provided for the subdomains of the VABS (Sparrow et al., 1984). The results of these analyses indicated that there were different patterns of performance observed across the three subdomains of the VABS communication domain, Wilks’s L 5 .06, F(2, 34) 5 117.03, p , .001, g2 5 .94. Follow-up pairwise comparisons indicated significantly higher scores on expressive communication than receptive communication, t(1, 17) 5 22.35, p 5 .03, and written communication, t(1, 17) 5 8.17, p , .001. Also, children with WS had significantly higher scores on receptive communication than written communication, t(1, 17) 5 15.69, p , .001. Therefore, it appears that expressive communication may be contributing more to the overall strength of performance on the communication domain in the WS group. No other statistically significant mean differences on the other domains of the VABS were observed between the two groups. Another potential contributor to the group differences on the communication domain in the

present study is socioeconomic status (SES). Past research has indicated a strong relationship between SES (i.e., annual income, level of maternal education, etc.) and expressive language during the preschool years (Brooks-Gunn, Duncan, & Britto, 1999; Stipek & Ryan, 1997; Walker, Greenwood, Hart, & Carta, 1994). It is possible that the difference observed on performance on the communication domain and expressive communication subdomain of the VABS was influenced by one group a having higher SES. To examine whether SES could be related to performance on the communication domain and expressive communication subdomain, Pearson r correlations were performed. Income and maternal level of education were used to approximate SES. No statistically significant correlations were observed for either group between the communication domain and income, WS, r(16) 5 0.38, p 5 .15; DD, r(15) 5 20.43, p 5 .11, or maternal level of education, WS, r(16) 5 0.07, p 5 .78; DD, r(15) 5 20.22, p 5 .44. Similarly, no statistically significant correlations were observed for expressive communication and income, r(16) 5 0.13, p 5 .68, or maternal level of education, r(17) 5 0.13, p 5 .63, for the WS group. For the DD group, there was a statistically significant association between expressive communication and maternal level of education, r(15) 5 20.51, p 5 .05. Thus, it seems that for children with DD in the present study, as maternal level of education increased parent report of expressive communication on the VABS decreased. However for the DD group, there was not a statistically significant association between expressive communication and income, r(15) 5 0.32, p 5 .24. It is important to note that many of the correlation coefficients are suggestive of an association, but may not have reached statistical significance because of the small sample size in the present study.

Table 3 Means, Standard Deviations, and Ranges for Adaptive Behavior Domain Standard Scores Williams syndrome

Developmental disabilities

Domain

M

SD

Range

M

SD

Range

Communication Daily living Socialization Motor skills

74.44 60.11 73.83 61.28

14.24 12.83 13.72 16.01

46–105 39–94 49–103 40–102

65.74 62.68 70.21 65.63

11.12 10.89 10.78 25.38

52–99 48–96 55–101 33–133

L. J. Hahn, D. J. Fidler, and S. L. Hepburn

55

EAAIDD DOI: 10.1352/1944-7558-119.1.49

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

Further analyses were conducted to examine within-individual performance on the VABS in children with WS. Results of a repeated measures ANOVA using the four domains of the VABS demonstrated a significant within-individual effect, Wilks’s L 5 .45, F(3, 35), p 5 .001, g2 5 .55 (see Table 3 for means and standard deviations). Follow-up pairwise comparisons indicated significantly higher scores on the communication domain than the daily living domain, t(1, 17) 5 4.77, p , .001, in the WS group. Similarly, children with WS had higher mean scores on the socialization domain than the daily living domain, t(1, 17) 5 6.43, p , .001, and the motor skills domain, t(1, 17) 5 3.77. p 5 .002. In addition, children with WS had higher mean scores on the communication domain when compared to the motor skills domain, t(1, 17) 5 4.13, p 5 .001. No other meaningful differences were observed between communication and socialization or daily living and motor skills within the WS group. Because of previous reports of impairments in fine motor skills in WS (Dilts et al., 1990; Mervis & Klein-Tasman, 2000; Udwin & Yule, 1991), it is possible that these impairments could influence adaptive functioning in both the daily living and motor skills domains. To explore the relationship between fine motor skills and adaptive functioning, the daily living and motor skills domains of the VABS were compared to the fine motor subscale of the MSEL. Pearson r correlations indicated that there were no statistically significant associations between fine motor raw scores and either the motor skills domain, r(15) 5 0.06, p 5 .82, or the daily living domain, r(15) 5 0.07, p 5 .80.

Problem Behaviors in WS To explore the within-individual performance on the five subscales of the DBC-P in children with WS, a repeated measures ANOVA was conducted using the average item score for each subscale. Average item scores were used to control for the different number of items on each subscale. Average item scores were calculated for each subscale by taking each participant’s score on the subscale and dividing it by the total number of items on the subscale. The results of this analysis demonstrated a significant within-individual effect, Wilks’s L 5 .30, F(4, 13), p 5 .02, g2 5 .70 (see Table 4 for means and standard deviations). 56

Table 4 Means, Standard Deviations, and Ranges for the Developmental Behavior Checklist Average Item Scores in Children with Williams Syndrome (N 5 18) Subscale

M

SD

Range

Disruptive and antisocial Self-absorbed Communication disturbance Anxiety Social relating Total problem behavior score

.36 .47 .51 .46 .21

.21 .29 .25 .26 .28

.08–.88 .10–.97 .15–1.15 .11–1.00 .00–1.10

.41

.18

.17–.79

Follow-up pairwise comparisons indicated significantly higher average item scores on the communication disturbance, self-absorbed, and anxiety subscales than the social relating subscales, communication disturbance, t(1, 16) 5 0.30, p 5 .002; self-absorbed, t(1, 16) 5 0.26, p , .001; anxiety, t(1, 16) 5 0.25, p 5 .02. However, these three areas of problem behavior did not differ significantly from one another. Also, children with WS had significantly higher average item scores on the communication disturbance subscale than the disruptive/antisocial subscale, t(1, 16) 5 0.15, p 5 .01.

Relationship Between Adaptive Behavior and Problem Behaviors Table 5 presents Pearson correlation data for the standard scores of the four domains of the VABS and the average item scores for the five subscales of the DBC-P for the WS group. Increased rates of problem behaviors on the social relating subscale were associated with poorer adaptive functioning on the VABS communication domain, r(17) 5 20.68, p , .01, and socialization domain, r(17) 5 20.58, p , .05. These results suggest that there is a negative relationship between social problem behaviors as measured by the DBC-P and parent report of adaptive communication and socialization in children with WS. Also, increased rates of problem behavior on the self-absorbed subscale was associated with poorer adaptive functioning on the VABS communication domain, r(17) 5 20.49, p , .05. There were no other statistically significant associations between the subscales of the DBC-P and performance on the four domains of the VABS. Adaptive and Problem Behavior in WS

EAAIDD DOI: 10.1352/1944-7558-119.1.49

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

Table 5 Correlations between Parent Report of Adaptive Behavior (VABS) and Problem Behaviors (DBC-P) in Children with Williams Syndrome (N 5 18) 1 VABS Standard Scores 1. Communication 2. Daily living 3. Socialization 4. Motor skills DBC-P Average Item Score 5. Disruptive/antisocial 6. Self-absorbed 7. Communication disturbance 8. Anxiety 9. Social relating 10. Total behavior problem score

-

2

3

4

5

6

0.56* 0.61** 0.61** 0.03 20.49* 0.77** 0.81** 20.16 20.29 0.56* 20.06 20.36 0.09 20.09

-

-

-

-

-

-

-

-

-

-

0.63** -

7

8

9

20.36 20.21 20.11 20.13

20.25 20.09 0.16 20.20

20.68** 20.45 20.58* 20.31

0.61* 0.56* -

0.50* 0.38 0.61* -

0.06 0.62** 0.26 20.06 -

10 20.43 20.32 20.28 20.12

0.81** 0.93** 0.76** 0.59* 0.50* -

*p , .05, **p , .01

Discussion Findings from the present study provide insight into the emerging adaptive profile of young children with WS. Our results suggest that during early childhood, young children with WS demonstrated a pattern of adaptive behavior performance that is similar to developmentally matched children with DD on the socialization, daily living, and motor skills domains of the VABS. Children with WS did, however, have a higher mean performance on the communication domain of the VABS than children with DD. Previous research on adaptive behavior in WS has primarily focused on describing adaptive functioning over the life course, with results suggesting that children with WS between the ages of four and eight have poorer adaptive behavior outcomes than developmentally matched children with DD (Gosch & Pankau, 1994). It is possible that during early childhood, children with WS have a pattern of performance similar to other developmentally matched children with DD on the VABS in all areas but communication. However, as children with WS develop, these skills do not progress at the same rate as their developmentally matched peers. Further, it seems that strengths in expressive L. J. Hahn, D. J. Fidler, and S. L. Hepburn

communication may be driving strengths in adaptive communication in children with WS. Thus, it seems that although the expressive language strengths are not typically evident from developmental assessments in early childhood in WS (Jarrold et al., 1998; Mervis & Klein-Tasman, 2000; Signer-Harris et al., 1997), some aspects of expressive language strengths may already be detectable in adaptive behavior contexts. It is possible that adaptive communication is easier for children with WS because of their preference for using language skills for social purposes instead of informational purposes (Ja¨rvinen-Pasley et al., 2008). However, it is also possible that these strengths in adaptive communication are related to children with WS in the present sample having higher, albeit not statistically significant, raw scores on the expressive language subscale of the MSEL. Further, it does not appear that the higher expressive language scores observed for children with WS in the present study was the result of the relationship that has been noted between expressive language and SES (Brooks-Gunn et al., 1999; Stipek & Ryan, 1997; Walker, Greenwood, Hart, & Carta, 1994). However for children with DD, a negative relationship was observed between expressive language and maternal level of education. This finding is puzzling and stands in contrast to 57

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

the relationship that has been observed in other studies examining the influence of SES on expressive language (Brooks-Gunn et al., 1999; Stipek & Ryan, 1997; Walker et al., 1994). It is possible that mothers with more education were more conservative in their description of their child’s adaptive expressive language skills, leading to lower scores. More research is needed to examine the similarities and differences in adaptive behavior between individuals with WS and individuals with DD to gain insight into whether there is a distinct adaptive behavior profile in WS and how this profile is associated with overall development. Research into the behavioral phenotype of WS has focused on the topic of hypersociability, and past studies on adaptive behavior have suggested that older children and adults with WS have higher performance on the socialization domain than they do on the communication domain of the VABS (Cherniske et al., 2004; Greer et al., 1997; Howlin et al., 1998; Howlin et al., 2010; Mervis et al., 2001). Based on these previous reports, it would not have been surprising for young children with WS to have shown a higher mean performance on the socialization domain than children with DD. However, in the present investigation, children with WS did not show statistically significantly stronger socialization standard scores than children in the DD comparison group (WS M 5 73.83, DD M 5 70.21). Furthermore, performance on the socialization domain did not emerge as the strongest domain for children with WS when examining within-individual differences in performance on the VABS. Although both the communication and socialization domains appeared to be areas of relative strength for this young sample of children with WS, there were no statistically significant differences observed between these two domains. In fact, the mean level of performance for the standard scores on the communication and socialization domains differed on average by less than one point within the WS group. Again, these findings stand in contrast to previous studies on adaptive behavior in older children with WS, which have reported stronger socialization than communication domain scores on the VABS in this population (Cherniske et al., 2005; Greer et al., 1997; Howlin et al., 1998; Howlin et al., 2010; Mervis et al., 2001). A critical difference between the present study and previous studies reporting 58

EAAIDD DOI: 10.1352/1944-7558-119.1.49

these results in children with WS relates to the developmental time period examined. It is possible that during early childhood, the social relatedness strengths associated with the WS behavioral phenotype (Fidler, Hepburn, Most, Philofsky, & Rogers, 2007) may not be translating into adaptive strengths in this population. Nonetheless, when examining the withinindividual performance in the WS group, children with WS did show higher mean standard scores on both the communication and socialization domains than the other domains of adaptive functioning as measured by the VABS. In the present investigation, performances on the motor skills domain were significantly lower than performance on the socialization domain in the WS group. The daily living domain had the lowest performance scores and appears to be emerging as an area of weakness in young children with WS, even before the age of five (Greer et al., 1997; Mervis et al., 2001). There are numerous potential accounts for why these skills may be emerging with less competence than other adaptive skill areas. For example, previous studies have indicated that motor skills in children 6 years and under, as measured by the VABS, are a relative weakness for this population (Gosch & Pankau, 1994; Mervis et al., 2001). Interestingly, the skills that make up the daily living domain rely upon the use of motor skills (e.g., self-feeding, dressing, household chores), and thus emerging difficulties in daily living may be observed as a function of difficulties with fine motor coordination and visuomotor construction. In the present study, children with WS did have significantly lower fine motor skills as measured by the MSEL than children with DD. However, a statistically significant relationship was not observed between the fine motor skills subscale of the MSEL and the motor skills and daily living domains of the VABS. In fact, the correlation coefficients for these analyses were relatively close to zero, which further suggests little meaningful association between these variables in the present study. Therefore, it seems that in the present study early difficulties in fine motor skills may not be influencing daily living skills and adaptive motor skills. Future studies should continue to explore the relationship between impairments in fine motor skills and visuomotor construction on adaptive skills. Also, more research is needed to examine the development of adaptive motor skills in children with WS over the age of six. Adaptive and Problem Behavior in WS

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

Alternatively, if the motor skills required to complete these tasks are not compromised, it is possible that other challenges in the area of executive function and goal directedness (i.e., planning, working memory, coordination) are driving weakness in this domain. Yet another possible explanation for this finding may relate to the choices made by parents of children with developmental disabilities during day-to-day activities, as parents may demonstrate lower expectations for daily living skills when children are evidencing delays in other areas. Overall, then, more research is needed to examine the factors contributing to daily living challenges in children with WS. Perhaps the use of more fine-grained measures of motor skills, executive function, and parenting behaviors will provide insight into the interaction between these skills and adaptive behavior. Research on problem behaviors in WS has noted problems with anxiety, fears, attention problems, distractibility, impulsivity, poor adaptability, and hyperactivity (Davies et al., 1998; Dilts et al., 1990; Dykens, 2003a; Dykens & Rosner, 1999; Einfeld et al., 1997; Einfeld et al., 2001; Gosch & Pankau, 1997; Perez-Garcia et al., 2011; Pober & Dykens, 1996; Tomc et al., 1990; Udwin, 1990). However, in the present study, children with WS showed the highest average item scores for problem behavior in communication disturbance. Average item scores on the communication disturbance subscale were significantly higher than the average item scores on the disruptive/antisocial and social relating subscales. Past research into the language profile of WS has noted that there are strengths in expressive language that are coupled with difficulties, such as the tendency to use words in strange or uncommon ways, difficulties in grammar, and problems with monitoring ungrammatical sentences (Bellugi, Wang, & Jernigan, 1994; Dykens, 2003b; Grant, Valian, & Karmiloff-Smith, 2002; Vicari, Caselli, Gagliardi, Tonucci, Volterra, 2002). It is possible that the language profile associated with WS leads parents to report problems associated with communication because the language profile makes communicating with their child more difficult. In the present study children with WS had higher average item scores for problem behavior on the anxiety subscale than the social relating. On average, children in the present study showed the least amount of difficulty on the social L. J. Hahn, D. J. Fidler, and S. L. Hepburn

EAAIDD DOI: 10.1352/1944-7558-119.1.49

relating subscale. Considering the social strengths associated with WS, it is not surprising that problem behavior in this area is low in this population. In the present study, young children with WS also had higher average item scores for problem behavior on the self-absorbed subscale of the DBC-P than the social relating subscale. These findings may be related to the developmental appropriateness of the items on this scale and the time period examined. Items on this scale include mouthing objects, hums, throws, screams, and having accidents even though toilet trained. Considering the developmental level of the current sample, these behaviors may actually be more typical behaviors in early childhood that become problem behaviors as children develop. Einfeld et al. (2001) also suggested this notion in their longitudinal study of problem behavior in WS using the DBC-P. Einfeld et al. found that during middle childhood, children with WS had higher mean scores on the self-absorbed subscale than they did in early adolescence. The authors suggested that these findings might be a reflection of changes in the developmental status of their participants over the course of the study. In order to fully examine the developmental appropriateness of these behaviors in early childhood for children with WS, future studies should include a comparison group of developmentally matched children with DD. The present study also sought to explore the relationship between problem behaviors and dayto-day functioning in children with WS. Interestingly, despite the elevated levels of problem behavior reported by parents in communication disturbance and anxiety, associations between these areas and any of the adaptive skills examined were not observed. Considering the high rates of anxiety associated with WS (Davies et al., 1998; Dilts et al., 1990; Dykens, 2003a; Dykens & Rosner, 1999; Einfeld et al., 1997; Einfeld et al., 2001) and difficulties in some aspects of expressive language (i.e., grammar and word use; Bellugi et al., 1994; Dykens, 2003b; Grant et al., 2002; Vicari et al., 2002), it would not be surprising for problem behaviors in these areas to interfere with day-to-day functioning later in development. It has been suggested by Dykens (1998) that the personality profile associated with WS (e.g., overly friendly, eager to engage with others, emotional attunement, affectionate, and loquacious; Dilts et al., 1990; Gosch & Pankau, 1997; 59

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

Ja¨rvinen-Pasley et al., 2008; Jones et al., 2001; Mervis & Klein-Tasman, 2000; Plesa-Skwerer et al., 2006; Tager-Flusberg et al., 2006) may serve as a protective factor for problem behavior in children with WS. The findings of the present study add support to this hypothesis. In the present study, children with WS who had higher performance on the communication and socialization domains of the VABS had lower rates of social relating problems and problems with being self-absorbed as measured by the DBC-P. The social strengths observed in children with WS, combined with strengths in some aspects of language development, may facilitate more positive interactions with others (Dykens, 1998) and, in turn, influence parental report on both the communication and socialization domains leading to higher performance on the VABS. More research is needed to explore the proposed protective influence of the WS personality profile on both problem and adaptive behavior in children and adults with WS. There are several limitations to the present study. In the present study, the DBC-P was not administered to the comparison group of children with DD. Because of this, it was not possible to identify were differences in rates and patterns of problem behaviors between young children with WS and their developmentally matched peers. More research is needed to examine the pattern of problem behaviors in young children with WS and the relationship between adaptive behavior and problem behaviors. Also, due to the small sample size, the findings presented should be interpreted with caution, as initial evidence of emerging patterns of performance in adaptive functioning in this population. Another limitation relates to the nature of the measures used in this study. Both the Vineland Adaptive Behavior Scales (Sparrow et al., 1984) and the Developmental Behavior Checklist (Einfeld & Tonge, 2002) are based on parental report and interpretations of their child’s behavior. Parent report measures are based on parent interpretation of observed behavior in day-to-day life instead of behavior that is elicited during a task or situation. Therefore, it is possible that the report of these behaviors may be influenced by parent perception, leading to discrepancy in the reporting of behaviors. Future studies may benefit from using multiple measures of adaptive behavior and problem behaviors, as well as multiple informants (i.e., teachers, occupational therapists, etc.) to 60

EAAIDD DOI: 10.1352/1944-7558-119.1.49

fully understand how these behaviors are manifesting in different situations. Nonetheless, the present study adds to the growing body of research focused on characterizing behavioral phenotypes in children with neurogenetic disorders. Specifically, this study provides an important step forward in the examination of adaptive behavior in children with WS by investigating how this profile is emerging during early childhood. More research is needed to examine the adaptive profile of children with WS. Although Howlin et al. (2010) have conducted longitudinal and crosssectional studies in adults, to fully characterize the trajectory of this profile, additional longitudinal studies of adaptive behavior are necessary. Continuing to characterize adaptive behavior and problem behavior in WS will help to identify areas for targeted intervention to help promote positive development in individuals with WS. Future studies on adaptive behavior and problem behavior in WS should also include a comparison group of developmentally matched peers with other developmental disabilities to identify whether these patterns of behavior are syndrome specific.

References Bayley, N. (1993). Bayley Scales of Infant Development (2nd edition). San Antonio, TX: The Psychological Corp. Bellugi, U., Lichtenberger, L., Jones, W., Lai, Z., & St. George, M. (2001). The neurocognitive profile of Williams syndrome: A complex pattern of strengths and weaknesses. Journal of Cognitive Neuroscience, 12(Supplement), 7–29. doi:10.1162/089892900561959 Bellugi, U., & St. George, M. (2001). Journey from cognition to brain to gene: Perspectives from Williams syndrome. Cambridge, MA: The MIT Press. Bellugi, U., Wang, P., & Jernigan, T. (1994). Williams syndrome: An unusual neuropsychological profile. In S. Broman & J. Grafman (Eds.), Atypical cognitive deficits in developmental disorders: Implications for brain function (pp. 23– 56). Hillsdale, NJ: Erlbaum. Brooks-Gunn, J., Duncan, G. J., & Britto, P. R. (1999). Are socioeconomic gradients for children similar to those for adults? Achievement and health of children in the United States. In D. P. Keathing & C. Hertzman Adaptive and Problem Behavior in WS

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

(Eds.), Developmental health and the wealth of nations: Social, biological, and education dynamics (pp. 94–124). New York, NY: The Guilford Press. Bruininks, R., Woodcock, R., Weatherman, R., & Hill, B. (1984). Scales of Independent Behavior: Woodcock-Johnson Psycho-Educational Measures. Allen, TX: DLM Teaching Resources. Cherniske, E. M., Carpenter, T. O., Klaiman, C., Young, E., Bregman, J., Insogna, K., …Pober, B. R. (2004). Multisystem study of 20 older adults with Williams syndrome. American Journal of Medical Genetics (Part A), 131(3), 255–264. doi:10.1002/ajmg.a.30400 Davies, M., Howlin, P., & Udwin, O. (1997). Independence and adaptive behavior in adults with Williams syndrome. American Journal of Medical Genetics, 70(2), 188–195. doi:10.1002/ (SICI)1096-8628(19970516)70:2,188::AIDAJMG16.3.0.CO;2-F Davies, M., Udwin, O., & Howlin, P. (1998). Adults with Williams syndrome. Preliminary study of social, emotional and behavioural difficulties. The British Journal of Psychiatry, 172(3), 273–276. doi:10.1192/bjp.172.3.273 de Bildt, A., Sytema, S., Kraijer, D., Sparrow, S., & Minderaa, R. (2005). Adaptive functioning and behavior problems in relation to level of education in children and adolescents with intellectual disability. Journal of Intellectual Disability Research, 49(9), 672–681. doi:10.1111/ j.1365-2788.2005.00711.x Di Nuovo, S., & Buono, S. (2011). Behavioral phenotypes of genetic syndromes with intellectual disability: Comparison of adaptive profiles. Psychiatry Research, 189(3), 440–445. doi:10.1016/j.psychres.2011.03.015 Dilts, C. V., Morris, C. A., & Leonard, C. O. (1990). Hypothesis for development of a behavioral phenotype in Williams syndrome. American Journal of Medical Genetics, 37(6), 126–131. doi:10.1002/ajmg.1320370622 Ditterline, J., & Oakland, T. (2009). Relationships between adaptive behavior and impairment. In S. Goldstein & A. Jack (Eds.), Assessing impairment: From theory to practice. (pp. 31–48). New York, NY: Springer Science + Business Media. Dodson, S., & Bangs, T. E. (1979). Birth to Three Developmental Scale. Allen, TX: DLM Teaching Resources. Doll, E. A. (1965). The Vineland social maturity scale. Circle Pines, MN: American Guidance Service. L. J. Hahn, D. J. Fidler, and S. L. Hepburn

EAAIDD DOI: 10.1352/1944-7558-119.1.49

Dykens, E. M. (1998). Maladaptive behavior and dual diagnosis in persons with genetic syndromes. In J. A. Burack, R. M. Hodapp, & E. Zigler (Eds.), Handbook of mental retardation and development (pp. 542–562). New York, NY: Cambridge University Press. Dykens, E. M. (2003a). Anxiety, fears and phobias in Williams syndrome. Developmental Neuropsychology, 23, 291–316. doi:10.1080/87565641. 2003.9651896 Dykens, E. M. (2003b). The Williams syndrome behavioral phenotype: The ‘whole person’ is missing. Current Opinion in Psychiatry, 16, 532–528. Dykens, E. M., Hodapp, R. M., & Finucane, B. M. (2000). Genetics and mental retardation syndromes: A new look at behavior and interventions. Baltimore, MD: Paul H. Brookes. Dykens, E. M., & Rosner, B. A. (1999). Refining behavioral phenotypes: Personality-motivation in Williams and Prader-Willi syndromes. American Journal on Mental Retardation, 104(2), 158–169. Einfeld, S. L., & Tonge, B. J. (1992). Manual for the Developmental Behavior Checklist. Melbourne, Australia: Monash University Centre for Developmental Psychiatry and Psychology. Einfeld, S. L., & Tonge, B. J. (2002). Manual for the Developmental Behavior Checklist: Primary Carer Version (DBC-P) and Teacher Version (DBC-T) (2nd edition). Melbourne, Australia: Monash University Centre for Developmental Psychiatry and Psychology. Einfeld, S. L., Tonge, B. J., & Florio, T. (1997). Behavioral and emotional disturbance in individuals with Williams syndrome. American Journal on Mental Retardation, 102(1), 45–53. doi:10. 1352/0895-8017(1997)102,0045:BAEDII.2.0. CO;2 Einfeld, S. L., Tonge, B. J., & Rees, V. W. (2001). Longitudinal course of behavioral and emotional problems in Williams syndrome. American Journal on Mental Retardation, 106(1), 73– 81. Ewart, A. K., Morris, C. A., Atkinson, D., Jin, W., Sternes, K., Spallone, P., …Keating, M. T. (1993). Hemizygosity at the elastin locus in a developmental disorder, Williams syndrome. Nature Genetics, 5(1), 11–16. doi:10.1038/ ng0993-11 Fidler, D. J., Hepburn, S. L., Most, D. E., Philofsky, A., & Rogers, S. J. (2007). Emotional responsivity in young children with 61

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

Williams syndrome. American Journal of Mental Retardation, 112(3), 194–206. doi:10. 1352/0895-8017(2007)112[194:ERIYCW]2.0. CO;2 Fisch, G. S., Carpenter, N., Holden, J. J. A., Simensen, R., Howard-Peoples, P. N., Maddalena A., …Nance, W. (1999). Longitudinal assessment of adaptive and maladaptive behaviors in fragile X males: Growth, development and profiles. American Journal of Medical Genetics, 83, 308–312. doi:10.1002/ (SICI)1096-8628(19990402)83:4,257::AIDAJMG5.3.0.CO;2-U Folio, M. R., & Fewell, R. R. (1983). Peabody Developmental Motor Scales. Allen, TX: DLM Teaching Resources. Gosch, A., & Pankau, R. (1994). Social-emotional and behavioral adjustment in children with Williams-Beuren syndrome. American Journal of Medical Genetics, 53, 335–339. doi:10.1002/ ajmg.1320530406 Gosch, E. A., & Pankau, R. (1997). Personality characteristics and behavior problems in individuals of different ages with Williams syndrome. Developmental Medicine and Child Neurology, 39, 527–533. Grant, J., Valian, V., & Karmiloff-Smith, A. (2002). A study of relative clauses in Williams syndrome. Journal of Child Language, 29(2), 403–416. doi:10.1017/S030500090200510X Greer, M. K., Brown, F. R., Pai, G. S., Choudry, S. H., & Klein, A. J. (1997). Cognitive, adaptive, and behavioral characteristics of Williams syndrome. American Journal of Medical Genetics, 74(5), 521–525. doi:10.1002/(SICI)10968628(19970919)74:5,521::AID-AJMG13.3.0. CO;2-E Hodapp, R. M., & DesJardin, J. L. (2002). Genetic etiologies of mental retardation: Issues for interventions and interventionists. Journal of Developmental and Physical Disabilities, 14(4), 323–338. doi:10.1023/A:1020378718237 Howlin, P., Davies, M., & Udwin, O. (1998). Cognitive functioning in adults with Williams syndrome. Journal of Child Psychology and Psychiatry, and Allied Disciplines, 39(2), 183–189. Howlin, P., Elison, S., Udwin, O., & Stinton, C. (2010). Cognitive, linguistic and adaptive functioning in Williams syndrome: Trajectories from early to middle adulthood. Journal of Applied Research in Intellectual Disabilities, 23(4), 322–336. doi:10.1111/j.1468-3148.2009.00536.x 62

EAAIDD DOI: 10.1352/1944-7558-119.1.49

Jarrold, C., Baddeley, A. D., & Hewes, A. K. (1998). Verbal and nonverbal abilities in the Williams syndrome phenotype: Evidence for diverging developmental trajectories. Journal of Child Psychology and Psychiatry, 39, 511–523. doi:10.1111/1469-7610.00347 Ja¨rvinen-Pasley, A., Bellugi, U., Reilly, J., Mills, D. L., Galaburda, A., Reiss, A. L., & Korkenberg, J. R. (2008). Defining the social phenotype in Williams syndrome: A model for linking gene, the brain, and behavior. Development and Psychopathology, 20(1), 1–35. doi:10.1017/ S0954579408000011 Jones, W., Bellugi, U., Lai, Z., Chiles, M., Reilly, J., Lincoln, A., & Adolphs, R. (2001). Hypersociability: The social and affective phenotype of Williams syndrome. In U. Bellugi & M. St. George (Eds.), Journey from cognition to brain to gene: Perspectives from Williams syndrome. Cambridge, MA: The MIT Press. Lambert, N., & Windmiller, M. (1981). AAMD adaptive behavior scale—School edition. Monterey, CA: McGraw Hill. Martens, M. A., Wilson, S. J., & Reutens, D. C. (2008). Research review: Williams syndrome: A critical review of the cognitive, behavioral, and neuroanatomical phenotype. Journal of Child Psychology and Psychiatry, and Allied Disciplines, 49(6), 576–608. doi:10.1111/ j.1469-7610.2008.01887.x Martin, S. C., Wolters, P. L., & Smith, A. M. (2006). Adaptive and maladaptive behavior in children with Smith-Magenis syndrome. Journal of Autism and Developmental Disorders, 36(4), 541-552. doi:10.1007/s10803-006-0093-2 Mervis, C. B. (1999). The Williams syndrome cognitive profile: Strengths, weaknesses, and interrelations among auditory short-term memory, language and visuo-spatial constructive cognition. In R. Fivush, W. Hirst, & E. Winigrad (Eds.), Essays in honor of Ulrich Neisser. Mahwah, NJ: Lawrence Erlbaum. Mervis, C. B., & Klein-Tasman, B. P. (2000). Williams syndrome: Cognition, personality, and adaptive behavior. Mental Retardation and Developmental Disabilities Research Reviews, 6, 148– 158. doi:10.1002/1098-2779(2000)6:2,148:: AID-MRDD10.3.0.CO;2-T Mervis, C. B., & Klein-Tasman, B. P. (2004). Methodological issues in group-matching designs: Levels for control variable comparisons and measurement characteristics of Adaptive and Problem Behavior in WS

AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2014, Vol. 119, No. 1, 49–63

control and target variables. Journal of Autism and Developmental Disorders, 34(1), 7–17. doi:10.1023/B:JADD.0000018069.69562.b8 Mervis, C. B., Klein-Tasman, B. P., & Mastin, M. E. (2001). Adaptive behavior of 4- through 8year-old children with Williams syndrome. American Journal of Mental Retardation, 106(1), 82–93. doi:10.1352/0895-8017(2001)106,0082: ABOTYO.2.0.CO;2 Mervis, C. B., & Robinson, B. F. (2003). Methodological issues in cross-group comparisons of language and/or cognitive development. In Y. Levy & J. Schaeffer (Eds.), Language competence across populations: Toward a definition of specific language impairment (pp. 233–258). Mahwah, NJ: Lawrence Erlbaum. Mervis, C. B., Robinson, B. F., Bertrand, J., Morris, C. A., Klein-Tasman, B. P., & Armstrong, S. C. (2000). The Williams syndrome cognitive profile. Brain and Cognition, 44, 604–628. Mullen, E. (1995). Mullen Scales of Early Learning. Circle Pines, MN: American Guidance Service. Perez-Garcia, D., Granero, R., Gallastegui, F., Perez-Jurado, L. A., & Brun-Gasca, C. (2011). Behavioral features of Williams Beuren syndrome compared to Fragile X syndrome and subjects with intellectual disability without defined etiology. Research in Developmental Disabilities, 32(2), 643–652. doi:10.1016/ j.ridd.2010.12.005 Plesa-Skwerer, D., Faja, S., Schofield, C., Verbalis, A., & Tager-Flusberg, H. (2006). Perceiving facial and vocal expressions of emotion in individuals with Williams syndrome. American Journal on Mental Retardation, 111(1), 15– 26. Pober, B. R., & Dykens, E. M. (1996). Williams syndrome: An overview of medical, cognitive, and behavioral features. Child and Adolescent Psychiatric Clinics of North America, 5(4), 929– 943. Singer Harris, N. G., Bellugi, U., Bates, E., Jones, W., & Rossen, M. L. (1997). Contrasting profiles of language development in children with Williams and Down syndromes. Developmental Neuropsychology, 13, 345–370. doi:10. 1080/87565649709540683 Sparrow, S. S., Balla, D. A., & Cicchetti, D. (1984). Vineland Adaptive Behavior Scales. Circle Pines, MN: American Guidance Service. Stipek, D. J., & Ryan, R. H. (1997). Economically disadvantaged preschoolers: Ready to learn L. J. Hahn, D. J. Fidler, and S. L. Hepburn

EAAIDD DOI: 10.1352/1944-7558-119.1.49

but further to go. Developmental Psychology, 33, 711–723. Strømme, P., Bjørnstad, P. G., & Ramstad, K. (2002). Prevalence estimation of Williams syndrome. Journal of Child Neurology, 17(4), 269–271. doi:10.1177/088307380201700406 Tager-Flusberg, H., Plesa-Skwerer, D. P., & Joseph, R. M. (2006). Model syndromes for investigating social cognitive and affective neuroscience: A comparison of autism and Williams syndrome. Social Cognitive and Affective Neuroscience, 1(3), 175–182. doi:10.1093/scan/nsl035 Tomc, S., Williamson, N., & Pauli, R. (1990). Temperament in Williams syndrome. American Journal of Medical Genetics, 36(3), 345–352. doi:10.1002/ajmg.1320360321 Udwin, O. (1990). A survey of adults with Williams syndrome and idiopathic infantile hypercalcaemia. Developmental Medicine & Child Neurology, 32(2), 129–141. doi:10.1111/ j.1469-8749.1990.tb16912.x Udwin, O., & Yule, W. (1991). A cognitive and behavioural phenotype in Williams syndrome. Journal of Clinical and Experimental Neuropsychology, 13(2), 232–244. Vicari, S., Caselli, M. C., Gagliardi, C., Tonucci, F. & Volterra, V. (2002). Language acquisition in special populations: A comparison between Down and Williams syndrome. Neuropsychologia 40, 2461–2470. doi:10.1016/ S0028-3932(02)00083-0 Walker, D., Greenwood, C. R., Hart, B., & Carta, J. (1994). Prediction of school outcomes based on early language production and socioeconomic factors. Child Development, 65, 606–621. Received 2/18/2013, accepted 3/3/2013. Editor-in-Charge: Leonard Abbeduto This research was funded by a grant from the March of Dimes (#12-FY03-47) awarded to Susan L. Hepburn and Deborah J. Fidler. Authors: Laura J. Hahn (e-mail: [email protected]), University of Kansas, Life Span Institute, 1000 Sunnyside Ave., Room 1052, Lawrence, KS, 66045-7555, USA; Deborah J. Fidler, Colorado State University, Department of Human Development & Family Studies, and Susan L. Hepburn, University of Colorado–Denver Health Sciences Center, Department of Psychiatry. 63