Autism Symptoms, Research Proposal Example

Introduction

With a cause for autism not yet understood, much of the focus is on effective interventions for children with autism. Kanner (1943) described autism as an enduring disorder that emerges in the preliminary years of life. Recent per-reviewed journals challenge this notion that autism is definitively stable in all individuals diagnosed earlier in life. Earlier studies, however, indicate that persons diagnosed with autism continue to show symptoms, whether profound or residual, through developmental stages; but, specific information about patterns of symptom change continues to be limited. This paper explores the existing literature on symptom presentation across various developmental stages of autism, ranging from patterns of start that include developmental regression, preschool through school-age years, and the adolescent/adulthood period. Autistic disorder, Hans Asperger’s disorder, childhood disintegrative disorder (CDD), Rett’s Disorder, and pervasive development disorder not otherwise specified (PDD-NOS) consist of a group of conditions referred to in the DSM (APA, 2000) as autism spectrum disorders (ASDs).

Autism affects development because it is strongly a developmental disorder. When compared to other neuropsychiatric disorders, it is one of the earliest developing, oftentimes emerging in infancy, and thus pervasively altering development in its earliest stages (Ozonoff et al., 2009). In addition, although other disorders have both “positive” and “negative” symptoms, the “negative” symptoms of autism may actually start as developmental delays, which later result in shortages when the delays persist (Ozonoff et al., 2009). Therefore, for the study of how symptoms of autism change in due course, one of the main topics of study is not whether obvious symptoms decrease, but how a lack of skills over a critical development period affects development in a variety of functional areas.

Literature Review

Literature specifically concerning children whose symptoms improve over time, either through specific interventions or as a group who “recover” or “remit”, has recently emerged (Helt et al, 2008). Helt et al (2008) propose that some children may lose their autism diagnosis by failing to meet DSM-IV criteria, with only subtle difficulties in pragmatics distinguishing this “recovered” group from typically developing controls on standardized tests. In addition to addressing questions relevant to broad categorical outcomes (e.g., diagnostic stability), they are increasingly recognizing the importance of tracking the development and manifestation of specific symptom areas over time.

Evidence continues to grow that symptom onset in autism often takes place before the age of 2 (Coonrod & Stone, 2004), but the age of first diagnosis has not been reduced accordingly. Most recent reports still estimate that the majority of children are diagnosed after 3 years of age (CDC, 2009). Reasons for the difference between reported concern and diagnosis are not completely known.

As indicated by retrospective analyses of home video-tapes (Werner et al, 2000), as well as more recently by studies of parent report (Ozonoff et al, 2009) and even observational data (Zwaigenbaum et al., 2009), symptoms of autism are present in some children by the age of 12 months. However, several groups have now confirmed that by looking at both standardized cognitive and language measures, and more subtle measures of affect and social reciprocity between both infant and mother, and infant and examiner, no clear differences are apparent between 6 month infants (siblings) who later develop autism and infant siblings who later appear to be developing in a typical trajectory (Ozonoff et al, 2009; Young et al, 2009). Study of infant siblings of children with autism has been critical in developing this understanding of every early symptom-onset patterns. Overall, research on early identification indicates that given more developmentally appropriate assessment tools, risk, if not diagnosis, can be established before the age of 2 in at least some children. However, it also indicates that at least in terms of behavioral assessment, early detection of symptom onset may not be possible before the age of 12 months.

More and more peer-reviewed investigations on young children are showing that significant improvement in symptoms and associated problems occur in some children with ASDs, particularly with early intervention. A critical question is whether there can still be improvements in skills during the school-age years. When comparing growth in school-age years to that during late adolescence, findings from one of the longest peer-reviewed journals indicate that growth in language is greater during school-age years compared to adolescence, and that cognitive ability remains stable during school age but may decline later in adolescence (Sigman & McGovern, 2005). Another peer-reviewed journal examined language and cognitive variables as predictors of adaptive behavior in communication and socialization, as well as more direct measures of autism symptoms, in children with autism or AS (Szatmari et al., 2009). While language and cognitive scores predicted communication, socialization, and autism symptoms, early language and cognitive scores were most predictive of communication and least predictive of the direct measure of autism symptoms. A follow-up examination of the developmental trajectories of children with AS found that although children with AS scored higher on most measures compared to those with autism or PDD-NOS, the pattern was the same in both groups for trajectories of communication and socialization scores from age 4-6 through adolescence, such that standard scores increased, but rate of growth slowed down considerably by late adolescence (Szatmari et al., 2009). Taken together, findings from these few peer-reviewed investigations indicate that while growth in skills appears to slow as children move into adolescence, children with ASDs may still make considerable progress in at least language and cognitive skills during the school-age years.

Studies investigating comorbidity have generally included the school-age population and upward, although a recent study investigating younger children reported high rates of comorbid psychopathology even in preschoolers (Gadow et al., 2004). In school-age children, studies are now beginning to explore whether subgroups of children with ASDs are prone to higher rates of comorbidity, with some indication that children with autism (compared to PDD-NOS) have higher rates of several significant comorbid symptoms such as depression and atypical behavior/psychosis (Pearson et al., 2006). Studies are also beginning to explore predictors of associated symptoms during school age. Although the literature is not completely consistent, higher intellectual functioning at earlier ages (defined by higher IQ scores) is generally associated with later internalizing symptoms (e.g., depression, anxiety), whereas lower intellectual functioning at earlier ages is generally associated with externalizing behaviors (e.g. challenging behaviors that affect others, such as aggression, irritability, hyperactivity) (Estes et al., 2007).

Adolescents and adults with ASDs have received relatively little attention in the literature compared to school-age children and, more recently, infants and toddlers. Very few large-scale peer-reviewed journals have followed children with autism into adulthood (Howlin et al., 2004; Sigman & McGovern., 2005). While these studies were quite detailed in variables that included cognitive, social and adaptive functioning, they were lacking in quantitative measurements of autism symptom domains. Thus, information is still limited with respect to if and how variability in core features of autism predict or are concurrently associated with various adult outcomes. Studies that include larger samples and more in-depth evaluations of ASDs-related features are required to report on how different aspects of the ASDs phenotype, as observed at different types of development, are related to outcomes in adolescence and adulthood.

Studies of adults with ASDs have also reported on the presence of comorbid medical conditions (e.g., epilepsy) of psychiatric disorders as a dimension of outcome. Billstedt and Gillberg (2005) found that about half of their sample of 120 adults with ASDs had a medical problem that required regular medical attention, though it should be noted that a relatively large percentage of this sample had additional diagnoses of severe intellectual disability (ID) and/or genetic syndromes (e.g., Fragile X Syndrome and Williams syndrome) that may have led to an unusually high number of medical problems in this group. Matson and colleagues (2010) found that among 377 adults, those with ASDs and comorbid psychopathology exhibited the lowest scores on the Vineland Adaptive Behavior Scales. Esbensen et al (2010) have found that over 60% of a community sample of adults with ASDs were receiving psychological and psychiatric services compared to only 19% of adults with Down syndrome (DS), and that receipt of psychological and psychiatric services related to overall independence among adults with ASDs. Studies of psychiatric comorbidity in adults with ASDs have not generally looked closely at early life predictors (besides IQ) of comorbid diagnoses. Particularly with respect to different characteristics of the ASDs phenotype (e.g. presence of insistence on sameness behavior and children who are ‘aloof’ vs. ‘active but odd), it is not yet understood whether certain individuals are more likely to develop depression or other psychiatric problems as adolescents and adults.

In addition to diagnostic status of ASDs or comorbid psychopathology, traditional measures of outcome include employment, number of close personal relationships, and other factors considered to be markers of adult independence. Howlin et al (2004) conducted a seminal study of 68 adults who were initially diagnosed with ASDs at an average age of 7 years. Based on combined information about the participants’ current employment, friendships (as measured by the ADI-R friendship item), and residential placement, 12% were rated as having a “Very Good” overall social outcome (i.e., paid employment, some friends, high level of residential independence), whereas more than half of the participants were rated as having “Poor” or “Very Poor” outcomes. Though higher IQ in childhood (i.e., nonverbal IQ score > 70) was associated with better adult outcomes, verbal and nonverbal IQ scores were not reliable predictors of outcome within the higher functioning individuals. That is, low IQ was found to be more meaningful as a predictor of poor outcome than high IQ predicting a good outcome. Given that more recent studies are following children who were assessed at ages younger than 7 years, it will be interesting to examine whether, and at what ages, verbal and nonverbal abilities in these children become predictive of various adolescent and adult outcome.

Discussion

Most of the literature summarized in this paper comes from peer-reviewed journals on children with ASDs. Additional studies of autism samples with large heterogeneity in symptomatology are critical for understanding predictors of various outcomes, but they may not provide answers to all questions about the nature of how symptoms change over time. Because specific outcomes of interest, such as “optimal outcomes”, are infrequent and not found in large numbers from even mid- to large-sized peer-reviewed investigations, more targeted studies that recruit specifically for such populations may be necessary.

Prospective, peer-reviewed journals that start with children as young as possible, preferably in early infancy, will allow for the most comprehensive investigation of symptom onset and progression over time, but large-scale study of pre-clinical to symptom-onset presentation is fraught with issues of feasibility, even in “high-risk” populations such as infant-sibling studies. While sibling studies yield a high percentage (possibly up to 20%) of individuals diagnosed with ASDs, these samples, in isolation, are not sufficiently large to produce enough statistical power to study inter-relationships among various symptom domains over time (Ozonoff et al, 2009). Thus, different types of studies, some prospective and some retrospective, may be necessary to answer remaining questions about how symptoms change over time in the development of ASDs.

Other limitations of peer-reviewed journals need to be considered in relation to specific hypotheses of developmental trajectory studies in autism. For instance, when considering questions about the trajectory of skill development in a particular area (e.g. language) compares with that of other developmental disorders (or typical development), comparison groups may be necessary, although there may be alternative cross-sectional approaches to determining how age affects very specific skill deficits (Thomas et al, 2009). These types of comparative trajectory studies are still necessary, because although much literature contributes significant understanding to how autism differs from other developmental problems in specific period of development, there is much to be learned about how specific deficits change over time and compare with disorders that show similar types of deficits. Do children with autism catch up in communication, cognitive ability, or neuropsychological constructs (e.g., theory of mind) as much as children who start out with similar cognitive abilities and do not have autism?

References

Billstedt, E., & Gillberg, C. (2005). Autism after adolescence: Population-based 13- to 22-year follow-up study of 120 individuals with autism diagnosed in childhood. Journal of Autism and Development Disorders, 35, 351-360.

Coonrod, E. E., & Stone, W. L. (2004). Early concerns of parents of children with autistic and non-autistic disorders. Infants & Young Children, 17, 258-268.

CDC (2009). Prevalence of autism spectrum disorders – autism and developmental disabilities monitoring network, United States, 2006. MMRW, 58, 1-20.

Esbenson, A., & Bishop, S., & Seltzer, M., & Greenberg, J., & Taylor, J. (2010). Comparisons between individuals with Down syndrome in adulthood. Intellectual and Developmental Disabilities, 115, 277-290.

Estes, A. M., & Dawson, G., & Sterling, L., & Manson, J. (2007). Level of intellectual functioning predicts patterns of associated symptoms in school-age children with autism spectrum disorder. [Journal: Peer-Reviewed Journal] American Journal on Mental Retardation, 112, 439-449.

Gadow, K. D., & DeVincent, C. J., & Pomeroy, J., & Azizian, A. (2004). Psychiatric symptoms in preschool children with PDD and clinic and comparison samples. Journals of Autism and Developmental Disorders, 34, 379-393.

Helt, M., & Kelley, E., & Kinsbourne, M., & Pandey, J., & Boorstein, H., & Herbert, M. et al. (2008). Can children with autism recover? If so, how? Neuropsychology Review, 18, 339-366.

Howlin, P., & Goode, S., & Hutton, J., & Rutter, M. (2004). Adult outcome for children with autism. Journal of Child psychology and psychiatry and Allied Disciplines, 45, 212-229.

Kanner, L. (1943). Autistic Disturbances of Affective Contact. Nervous Child, 2, 217-250.

Matson, J. L., & Hess, J. A., & Neal, D., & Mahan, S., & Fodstad, J. C. (2010). Trend in symptoms in children diagnosed with autistic disorder as measured by the Autism Spectrum Disorders-Diagnostic for Children (ASD-DC). Journal of Developmental and Physical Disabilities, 22, 47-56.

Ozonoff, S., & Young, G., & Steinfeld, M., & Hill, M., & Cook, I., & Hutman, T., et al. (2009). How early do parent concerns predict later autism diagnosis? [Journal: Peer-Reviewed Journal] Journal of Developmental and Behavioral Pediatrics, 30, 367-70.

Pearson, D. A., & Loveland, K. A., & Lachar, D., & Lane, D. M., & Reddoch, S. L., & Mansour, R., et al. (2006). A comparison of behavioural and emotional functioning in children and adolescents with autistic disorder and PDD-NOS. Child Neuropsychology, 12, 321-333.

Sigman, M., & McGovern, C. (2005). Improvement in cognitive and language skills from preschool to adolescence in autism. [Journal: Peer-Reviewed Journal] Journal of Autism and Developmental Disorders, 35, 15-23.

Szatmari, P., & Bryson, S., & Duku, E., & Vaccarella, L, & Zwaigenbaum, L., Bennett, T., et al (2009). Similar developmental trajectories in autism and Asperger syndrome: From Early childhood to adolescence. [Journal: Peer-Reviewed Journal] Journal of Child Psychology and Psychiatry and Allied Disciplines, 50, 1459-1467.

Thomas, M. S., & Annaz, D., & Ansari, D., & Scerif, G., & Jarrold, C., & Karmiloff-Smith, A. (2009). Using developmental trajectories to understand developmental disorders. [Journal: Peer-Reviewed Journal] Journal of Speech, Language, and Hearing Research, 52, 336-358.

Werner, E., & Dawson, G., & Osterling, J., & Dinno, N. (2000). Brief report: Recognition of autism spectrum disorder before one year of age: A retrospective study based on home videotapes. Journals of Autism and Developmental Disorders, 30, 157-162.

Young, G. S., & Merin, N., & Rogers, S. J., & Ozonoff, S. (2009). Gaze behavior and affect at 6 months: Predicting clinical outcomes and language development in typically developing infants and infants at risk for autism. [Journal: Peer-Reviewed Journal] Developmental Science, 12, 798-814.

Zwaigenbaum, L., & Bryson, S., & Lord, C., & Rogers, S., & Carter, A., & Carver, L., et al (2009). Clinical Assessment and Management of toddlers with suspected autism spectrum disorder: Insights from studies of high-risk infants. Pediatrics, 123, 1383-1391.