Comparison of adaptive behavior in children with heavy prenatal alcohol exposure or attention-deficit/hyperactivity disorder.

Behavioral and cognitive deficits are among the most devastating consequences of heavy prenatal alcohol exposure. Primary effects of this exposure can cause significant and permanent changes in brain structure and cognitive function (Archibald et al., 2001; Streissguth, 2007); secondary effects include difficulty in meeting demands of everyday life, i.e., adaptive behavior (Whaley et al., 2001). Behavioral and neuropsychological effects are seen in children with fetal alcohol syndrome (FAS) as well as those with heavy prenatal alcohol exposure, even if they lack the physical features required for an FAS diagnosis (Mattson and Riley, 2000; Mattson et al., 1997). The term fetal alcohol spectrum disorders (FASD) has been adopted to convey that the effects of prenatal alcohol exposure occur on a continuum (Bertrand et al., 2005). Individuals along the spectrum of effects have been noted to have deficits in behavior and adaptive function (Streissguth et al., 2004). Clinically, children with heavy prenatal alcohol exposure often meet diagnostic criteria for attention-deficit/hyperactivity disorder (ADHD) (Fryer et al., 2007; Steinhausen et al., 1993). Attention deficits, hyperactivity, and impulsivity are among the behavioral symptoms shared with ADHD. Given the heterogeneity of outcomes following prenatal alcohol exposure, the overlap in presentation with other clinical groups, and the lack of a definitive biomarker of prenatal alcohol exposure, accurate identification of children prenatally exposed to alcohol is often difficult, especially without confirmed maternal history of alcohol exposure. A distinct neurobehavioral profile of FASD would aid in distinguishing children prenatally exposed to alcohol from nonexposed children displaying similar behavioral characteristics. Direct comparison of individuals with FASD and those with ADHD but without a history of prenatal alcohol exposure will assist in the clarification of this profile. In addition, elucidating strengths and weaknesses within these groups may improve differential diagnosis and lead to earlier and more effective interventions for both populations. Only 3 published studies have compared neuropsychological function of children with FASD directly to children with ADHD or attention deficit disorder (ADD) (Coles et al., 1997; Nanson and Hiscock, 1990; Vaurio et al., 2008), and, in part, they have yielded contradictory results. The first investigation found no differences between the alcohol-exposed and ADD groups on parent-rated measures of behavior, or on computerized measures of attention (Nanson and Hiscock, 1990). The second study found that children with ADHD were best identified using behavior checklists and tasks designed to measure focused and sustained attention, while children with FASD were impaired on measures of visual spatial skills, and had decreased ability to encode new information and use it in problem solving (Coles et al., 1997). The most recent study compared children with heavy prenatal alcohol exposure to children with ADHD on measures of executive function. Both groups displayed deficits on the Wisconsin Card Sorting Test and a relative weakness on letter over category fluency. However, only the alcohol-exposed group displayed overall deficits on letter fluency and a relative weakness on the Trail Making Test–Part B over the Trail Making Test–Part A (Vaurio et al., 2008). To complement the few existing comparisons of neurobehavioral performance in children with ADHD and children with FASD, the current study focused on adaptive behavior, which is affected both in children with heavy prenatal alcohol exposure (Streissguth et al., 1991; Thomas et al., 1998) and in children with ADHD (Roizen et al., 1994; Stein et al., 1995). Adaptive function refers to an individual’s ability to meet developmentally appropriate expectations of personal independence and social responsibility (Sparrow et al., 1984) and includes the ability to perform everyday tasks (e.g., grooming and dressing) and adapt to changes in the environment. Management of everyday stressors and completion of basic tasks necessary for daily living are dependent on intact adaptive functioning. Despite the importance of adaptive function and the overlap in deficits found in FASD and ADHD, the 2 populations have not been compared directly on this domain. The Vineland Adaptive Behavior Scales (VABS) (Sparrow et al., 1984) is a semi-structured interview given to the child’s primary caregiver that assesses 3 aspects of adaptive behavior: communication, daily living skills, and socialization. Studies that have used the VABS have shown consistent deficits in individuals with prenatal alcohol exposure (LaDue et al., 1992; Streissguth et al., 1991). In one investigation of individuals with FASD (Streissguth et al., 1991), the average adaptive behavior scores were at the 7-year level although the mean age of the sample was 17 years. Highest scores were obtained on the daily living skills domain, with average scores at the 9-year level; lowest scores were on the socialization domain, with average scores at the 6-year level. Although a few subjects in the aforementioned sample obtained age appropriate scores on the daily living skills domain of the VABS, none obtained age appropriate scores on the communication or socialization domains. Socialization may be particularly affected in alcohol-exposed individuals. Specifically, as alcohol-exposed children age, their socialization abilities fail to develop at the expected rate, suggesting that these children have increasing difficulty with meeting the greater demands in social functioning that come with age (Thomas et al., 1998;Whaley et al., 2001). In a study comparing children with prenatal alcohol exposure to a clinic-referred sample of nonexposed children, investigators found that both groups were impaired on the VABS across all domains (Whaley et al., 2001). Although the 2 groups did not differ from each other on adaptive behavior scores, the alcohol-exposed group showed a greater decline in socialization standard scores with increasing age than did the nonexposed clinically referred controls. These results suggest that age-related deficits in socialization skills (i.e., greater impairment with increasing age) may be characteristic of children with prenatal alcohol exposure. Despite converging evidence suggesting a deficit in adaptive behavior in children with prenatal alcohol exposure, one study of prospectively identified children did not find differences in adaptive behavior in alcohol-exposed children relative to controls at age 6; scores for all groups fell within the average range (Coles et al., 1991). Because the participants included in this investigation were relatively young, the between group comparison may not have captured the more pronounced deficits that have been observed with increasing age. There is other evidence that adaptive impairments persist into adulthood and relate to adverse life outcomes such as disrupted school experiences, trouble with the law, and substance abuse problems (Streissguth et al., 2004). Children with ADHD also have deficits in adaptive behavior compared to controls as measured by the VABS (Clark et al., 2002; Roizen et al., 1994; Stein et al., 1995; Wilson and Marcotte, 1996). As in children with FASD, children with ADHD have clear deficits in socialization skills (Campbell, 1994; Greene et al., 1996). Adaptive function is lower than would be expected based on IQ in children with ADHD (Roizen et al., 1994) and there is evidence that for some, adaptive difficulties persist into adulthood (Barkley et al., 2006). It is not clear whether these deficits reflect a developmental delay or arrest, as the direct relationship between adaptive behavior scores and age has not been reported. However, there is evidence that deficits in ADHD become less pronounced over time (Faraone et al., 2006). A current aim of fetal alcohol research is to focus on cognitive and behavioral outcomes, and to better delineate neurobehavioral strengths and weaknesses on several domains of function in order to improve identification (Riley et al., 2003). Delineation of such profiles requires assessment of their specificity by comparing alcohol-exposed individuals to similar clinical groups, rather than outlining deficits only in relation to typically developing children. Such dual comparisons (to both typical and clinical comparison groups) will elucidate differential patterns of performance, add to the growing knowledge of neuropsychological and behavioral profiles associated with prenatal alcohol exposure, and ultimately improve differential diagnosis. Therefore, the current study compared adaptive behavior in children with histories of heavy prenatal alcohol exposure, nonexposed children with ADHD, and typically developing controls. The hypotheses of this study were as follows: (1) Children with heavy prenatal alcohol exposure and nonexposed children with ADHD would show deficits in adaptive function relative to controls, and (2) there would be a differential effect of age on socialization scores among groups; for alcohol-exposed children, standard scores would decrease with age, however, standard scores would be unrelated to age in children with ADHD and controls.