Literature Review on Autism Spectrum Disorders

Autism has become an increasing subject of interest, especially to researchers and medical professionals. This increase in interest is most likely due to the fact that autism is becoming an increasing problem in children, with the number of diagnoses doubling in just a four year period. In order to discover what may cause this disorder as well as finding effective ways to treat it, people must be informed and knowledgeable about autism. The current study discusses what ASD is, symptoms of this disorder, possible causes and risk factors, and methods of treatments and therapy, such as early intervention and sensory integration therapy.

This study hypothesizes that sensory integration therapy will significantly improve grades and school performance in children with autism.

Recently, it seems as if autism spectrum disorder (ASD) has been receiving a great deal of attention by those who work in the medical field, researchers, education providers, and parents as well. This is due to the fact that the number of diagnoses has increased significantly.

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In just a four year period, the number of recorded diagnoses for these types of disorders has doubled (Keen & Ward, 2004).

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This substantial increase in the diagnoses of ASDs could be due to the fact that doctors and other health professionals are becoming more aware of the criteria for these disorders, and are beginning to have greater recognition of ASD in more able, high functioning children. In the past, there have been several cases where high functioning children were first diagnosed with ADHD, and later received an ASD diagnoses (Keen & Ward, 2004). With the recent awareness of autism spectrum disorders, a more clear criteria has developed for the diagnoses of these disorders.

In broad terms, autism spectrum disorders is a group of developmental brain disorders, collectively called ASD. It is called autism spectrum disorder because the symptoms and levels of impairment for these disorders ranges widely in each individual with an ASD. (National Institute of Mental Health [NIMH], 2011). In fact, according to the National Institute of Mental Health (NIMH, 2011), some higher functioning children may only be mildly impaired by his or hers symptoms, while other children who are low functioning may have more severely impaired by his or hers symptoms, causing them to be severely disabled.

To diagnose an individual with ASD, one must meet the criteria listed in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition – Text Revision (DSM-IV-TR). Currently, there are five defined disorders that fall under the category of ASD. These disorders include autistic disorder (classic autism), Asperger’s disorder (Asperger’s syndrome), pervasive developmental disorder not otherwise specified (PDD-NOS), Rett’s disorder (Rett’s syndrome), and childhood disintegrative disorder (CDD) (NIMH, 2011). However, this review will focus mostly on the more common disorders, classic autism and Asperger’s syndrome. The NIMH (2011) has identified some key symptoms seen in individuals with ASD. While symptoms do vary from one child to the next, the symptoms tend to fall into three main areas. These three areas include social impairment, communication difficulties, and repetitive and stereotyped behaviors.

Children with autism have trouble with social interactions and find it difficult to engage in everyday social interactions. Some of these problems with social interactions may include having trouble with making eye contact, have trouble listening to and responding to other people in their environment, and having trouble picking up on social cues and reading peoples emotions. Children with ASD may respond unusually or inappropriately when others show feelings of anger, sadness, distress, or affection (Kamps, Leonard, Vernon, Dugan, & Delquadri, 1992). Children with autism also suffer from several communication issues, such as failing or being slow to respond to verbal attempts to get their attention, developing language at a slower pace than others, repeating words or phrases that they hear, and using words that are strange or out of place, that do not really make sense to people other than the child and those close to the child whom are familiar with the child’s communication style. The last important symptom seen in children with ASD is repetitive and stereotyped behavior.

Many children with ASD tend to have odd, repetitive actions and behaviors that may be referred to as stereotyped behaviors. An example of a stereotyped behavior might be a simple gesture of the arm that is repeatedly done by the child. Children with autism often have one subject or interest that they tend to overly focus on. They tend to become obsessed with one particular subject, and will learn everything they can about the subject of interest. Because autistic children seem to display several repetitive behaviors and thoughts, a set routine is usually the best environment for a child with ASD (NIMH, 2011).

While there have been many theories and suggestions of what may cause autism spectrum disorders, there is not one particular known cause of these disorders. A great deal of research has been done to examine possible causes of and risk factors for this disorder. Recently, there has been research on the hypotheses that maternal early life factors associated with hormone levels may have some correlation with being at risk of having a child with ASD. Ascherio, Lyall, Pauls, Santangelo, and Spiegelman (2011) conducted a study to see if they could find any relationships between certain maternal early life factors associated with hormone levels and the risk of having a child with an ASD. This study focuses on maternal early life factors, and how some of these reproductive and hormonal factors of mothers could put them at risk of having a child with ASD (Ascherio, Lyall, Pauls, Santangelo, & Spiegelman, 2011). The methods of this study included a cohort study with 61,596 women.

Data was collected from these women, which included age of menarche (first menstrual cycle), characteristics of menstrual cycle during adolescence, use of birth control, specifically oral contraceptives, prior to have given birth, body shape, and body mass index (BMI). The results of this study showed relationships between higher BMI’s at age 18, early age at menarche, and longer use of oral contraceptives prior to first birth, and being at risk for having a child with ASD (Ascherio et al., 2011).

Other risk factors for having a child with an ASD that have been studied include prenatal, or the period of time before the child is born, perinatal, or the period of delivery and immediately before and after delivery, and parental, or characteristics of the parents, factors. In a study done by Hertz-Piccottio et al. (2010), the authors examine possible parental, prenatal and perinatal factors associated with ASD. The methods of this study was a case-control study, using a cohort of children in China. Cases came from six special education schools and two Preschool Autistic Children Special Education Institutions in Tianjin, China (Hertz-Piccottio et al., 2010). The parental risk factors that were studied included parental ages at delivery, ethnicity, occupation, education, marriage of a close relative, exposure to toxins, personality, and family medical history of different illnesses (Hertz-Piccottio et al., 2010, p. 1313).

The prenatal risk factors that were examined in this study included maternal characteristics and behaviors during pregnancy, alcohol consumption, smoking and second hand smoke exposure, exposure to X-rays, attempt to terminate pregnancy, contact with toxins, emotional state, disease history, and medication history (Hertz-Piccottio et al., 2010, p. 1313). Some perinatal factors that were examined include infant gestational age at birth, fetal nuchal chord (umbilical chord wrapped around neck), cesarean delivery, and breech birth. Also included were newborn complications such as birth weight, delayed crying, and abnormal skin color due to an array of conditions such a hypoxia, apnoea, neonatal jaundice, and several other conditions (Hertz-Piccottio et al., 2010, p. 1313). The results of this study showed relationships between several of the factors examined and the risk of having a child with ASD. In relation to the prenatal risk factors studied, seven conditions during gestation were significantly associated with the risk of having a child with ASD, four of which showed the strongest relationship. The four prenatal risk factors that showed the strongest relationship included frequent maternal second-hand smoke exposure, chronic and acute medical conditions unrelated to pregnancy, maternal unhappy emotional state, and one or more gestational complications (Hertz-Piccottio et al., 2010, p. 1314).

For the perinatal risk factors that were studied, seven characteristics at the time of delivery were significantly associated with autism. These characteristics include abnormal gestational age, including preterm and post-term, nuchal chord, cesarean delivery, delayed crying, newborn complications, apnoea, and neonatal jaundice (Hertz-Piccottio et al., 2010, p. 1314). For the parental characteristics studied, results showed that gravidity > 1 and advanced paternal age at delivery were significantly associated with autism (Hertz-Piccottio et al., 2010, p. 1314).

Other studies have also done research on possible perinatal, prenatal, and parental risk factors for autism. In a study done by Agerbo et al. (2005), the authors created a study in Denmark of children with ASD. This study focused on possible perinatal risk factors for autism, as well as the associations between parental psychiatric history and socioeconomic status and the risk of having a child with autism. The following perinatal factors were investigated in this study: birth weight, gestational at birth, weight for gestational age, birth weight, Apgar score at 5 minutes, fetal presentation, mode of delivery, pregnancy characteristics such as multiple gestation, and parental characteristics such as maternal smoking, maternal and paternal ages, maternal citizenship, and number of previous pregnancies. Other factors considered were parental psychiatric history, that is, if the parent had been diagnosed with a psychiatric disorder prior to the date the child was diagnosed with autism, and socioeconomic factors, including maternal education and parental wealth (Agerbo et al., 2005).

As we begin to understand more about what exactly autism spectrum disorders are, what may cause these disorders, and how to diagnose children more accurately and sooner, the next step in being proactive with ASD is studying different treatment methods and developing new methods of treatment that may be more effective. The biggest impairment for most children with ASD is the social impairments caused by these disorders. Developing treatments that may help children with an ASD learn how to better interact in social situations could possibly be the most useful type of treatment for these children.

Researchers have been working on several different treatment methods for children with autism, especially treatments to help develop and improve social skills. In a study done by Koegel, Koegel, Hurley, and Frea (1992), the authors seek out to find a treatment to improve social skills in children with an ASD. This study assessed whether self-management could be used as a technique to improve extended responsiveness to verbal initiations from others, without the presence of a treatment provider. The methods of this study included four children, all of whom were diagnosed with autism. The results of the study showed that children with autism who displayed severe deficits in social skills could learn to self-manage responsivity to others in multiple community settings (Koegel, Koegel, Hurley, & Frea, 1992). Another method of treatment that is being explored is the use of social robots for the therapy of children with ASD. In a study done by Werry, Dautenhahn, Ogden, and Harwin (2001), the researchers developed a robotic agent that could help with therapy in children with autism. This study was called the AURORA project, which started in 1998. The results so far have been quite promising, and the social robot has proven to be a very useful tool for children with autism. It gives them the opportunity to practice social interactions and serves as a social mediator (Werry, Dautenhan, Ogden, & Harwin, 2001).

The treatment of autism is not a simple process. There is no single therapy or method of treatment that can completely cure an individual with autism. However, there are an assortment of treatments and therapies that have proven to be effective in treating children with autism. Quite often, children with autism combine different treatment methods and therapies to improve different skills. Some of the more common approaches at treating autism in children include behavioral procedures, such as early intervention and discrete trial trainings, speech therapy, dietary approaches, and occupational therapy ( Watling, Deitz, Kanny, & McLaughlin, 1999).

Early intervention, a behavioral analytic treatment for autism, is an intensive behavioral therapy that is started as soon as a child is diagnosed with autism, usually before age 5. This type of therapy is based on the principles of operant conditioning. In this type of treatment, therapists simplify children’s environment in order to maximize successes and minimize failures. For example, the therapist might break a behavior down into smaller units and teach each unit individually, eventually linking all of the units together, which may also be called chaining. Another method of simplification that a therapist may use is discrete trial format. Discrete trial format involves a one on one interaction with a therapist that is carefully planned out, in which the child receives short and clear instructions from the therapist, and is immediately reinforced for every correct response.

Another type of treatment for children with autism that is becoming more popular is occupational therapy. Occupational therapists are trained in teaching every day skills to help the individual being treated live as independently as possible. These skills can be very helpful to children with an ASD. One of the most well-known types of therapy occupational therapists use to help treat autism is sensory integration therapy. Those who practice this type of therapy hypothesize that the primary symptoms of autism are disturbances in sensory modulation. Consequently, children with autism have difficulties in social relating, communication, and language. Because children with autism have these disturbances in regulating sensory input appropriately, they suffer from several social and communication problems (Case-Smith & Bryan, 1999). The sensory integration approach attempts to stimulate and challenge the senses of the individual being treated (Cohn, 2001). A common symptom in individuals with autism is being either over stimulated under-stimulated by their environment. They often have trouble learning to combine and integrating their different senses.

These sensory difficulties may be a cause of communication problems and social interaction problems in children with autism. Because they have such difficulty regulating their sensory systems, they tend to have trouble socializing and interacting with others. Some individuals with autism practice certain stereotyped behaviors, such as lining up toys or moving a toy back and forth on a table. This may be an attempt to try and regulate their sensory systems. The sensory integration approach aims to help children with autism improve their sensory processing and modulation. There are three elements typically included in this approach: helping parents better understand their child’s behavior, helping parents/teachers modify the child’s environment in order to meet his or hers sensory needs, and helping children organize responses to sensory input. However, each sensory integration therapy session is unique to the individual being treated. Occupational therapists must consider different individuals’ unique needs and goals (Case-Smith & Bryan, 1999).

Sensory integration therapy is the most used technique in occupational therapy for the treatment of children with autism, with 95% of occupational therapists using this approach at least some of the time. The reason for its popularity in the treatment of autism is because of its proven efficacy in helping improve social interactions and communications. In a study done by Case-Smith and Bryan (1999) the authors found that sensory integration therapy can significantly increase mastery play, or the child’s interactions with the physical environment. They also found that sensory integration therapy significantly decreases non-engaged behaviors, or behaviors where the child is not interacting or minimally interacting with their environment. Examples of these behaviors include unfocused staring or aimless wandering. In a study by Cohn (2001), the author is concerned with parents’ perspectives of the sensory integration approach used in the treatment of their children. In this study, the author found that sensory integration was successful in helping parents understand their children’s problems. While there is a great deal of research that has been done on the sensory integration approach as a treatment for children with autism and the efficacy of this treatment in improving certain social behaviors, there is not much literature on the effects of sensory integration therapy on grades and school performance of children with autism. In consideration to prior research in relation to autism and the treatment methods, the current study hypothesizes that sensory integration therapy will significantly improves grades and school performance in children with autism.


Participants of this study will consist of young children with autism or another type of ASD, attending some type of day care or school for children with disabilities. Participants will be in the age group of 3 years old to 7 years old. There will be about 10-15 total participants.


This study will be a single-subject design, where each participant serves as his or hers own control group. The study will be conducted right after a break in school, such as winter break or summer break. When the students return from the break in school, they will attend school for three to four weeks without receiving any therapy or treatment. At the end of this period, grades will be assessed as well as general school performance such has participation and behavior. After the three week period of no therapy, intervention will be initiated and children will all receive sensory integration therapy. Children will receive this therapy within the school for six to eight weeks. At the end of this intervention period, grades and school performance will be assessed again.


The therapy sessions will take place in the day care or school building. Observations of the participants will be made in the classroom, both before the intervention period and during the intervention period. These observations will assess each child’s individual school performance, including things such as participation and class behaviors. Grades will also be assessed both before the intervention and during the intervention period. Students will return to school after their break and will not receive any therapy for three weeks. After the first three weeks, the intervention will be initiated and the children will each participate individually in a form of sensory integration therapy under the supervision of a trained occupational therapist. Each therapy session will be unique to the individual and his or hers unique needs or goals. At the end of the intervention period, grades will be assessed again. The grades and school performance of each child before the therapy was started will be compared with the grades and school performance assessed during and at the end of the therapy, using SPSS or some sort of statistical analysis program, to determine whether or not sensory integration therapy significantly improves grades and school performance in children with autism.

Agerbo, E., Eaton, W. W., Larsson, H. J., Madsen, K. M., Mortensen, P. B., Oleson, A. V., …Vestergaard, M. (2005). Risk factors for autism: Perinatal factors, parental psychiatric history, and socioeconomic status. American Journal of Epidemiology. 161(10), 916-925. doi:10.1093/aje/kwi123 Ascherio, A., Lyall, K., Pauls, D. L., Santangelo, S., & Spiegelman, D. (2011). Maternal early life factors associated with hormone levels and the risk of having a child with an autism spectrum disorder in the nurses health study II. Journal of Autism and Developmental Disorders,41, 618-

627. doi:10.1007/s10803-010-1079-7
Case – Smith, J., & Bryan, T. (1999). The effects of occupational therapy with sensory integration emphasis on preschool-age children with autism. American Journal of Occupational Therapy, 53, 489 – 497. Cohn, E. S. (2001). Parent perspectives of occupational therapy using a sensory integration approach. American Journal of Occupational Therapy, 55, 285-294. Hertz- Picciotto, I., Lv, C. C., Miao, R. J., Qi, L., Tian, J., Xi, W., & Zhang, X. (2010) Prenatal and perinatal risk factors for autism in china. Journal of Autism and Developmental Disorders, 40, 1311-1321. doi: 10.1007/s10803-010-0992-0 Kamps, D. M., Leonard, B. R., Vernon, S., Dugan, E. P., Delquadri, J. C., Gershon, B.,…Folk, L. (1992). Journal of Applied and Behavior Analysis, 25 (2), 281-288. Keen, D. & Ward, S. (2004). Autistic spectrum disorder a child population profile. The National Autistic Society, 8 (1), 39-48. Koegel, L. K., Koegel, R. L., Hurley, C., & Frea, W. (1992). Improving social skills and disruptive behavior in children with autism through self-management. Journal of Applied Behavior Analysis, 25, 341-353. Smith, Tristram. (1999). Outcome of early intervention for children with autism. Clinical Psychology: Science and Practice,6, (1), 33-49. U.S. Department of Health and Human Services, National Institutes of Health, National Institute of Mental Health. (2011). A parent’s guide to autism spectrum disorder (NIH Publication No. 11-5511). Retrieved from Watling, R., Deitz, J., Kanny, E. M., & McLaughlin, J. F. (1999). Current practice of occupational therapy for children with autism. American Journal of Occupational Therapy, 53, 498–505. Werry, I., Dautenhahn, K., Ogden, B., & Harwin, W. (2001). Can social interaction skills be taught by a social agent? The role of a robotic mediator in autism therapy.

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Literature Review on Autism Spectrum Disorders. (2016, Mar 09). Retrieved from

Literature Review on Autism Spectrum Disorders

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