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Early Detection of Autism in Infants and Toddlers

June 15th, 2010 Comments off

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At this very moment, thousands of infants and toddlers throughout the United States exhibit worrisome behavior. They are being managed by perplexed parents and remain unclassified by family practioners, but the developmental outcome of these very young children may brighten as the early diagnosis and consequential expedience of intervention becomes a reality. Anecdotal reports imply that children diagnosed with autism display characteristics of abnormal behavior at an early age, possibly from birth, and in fact, this early onset of such behaviors (prior to thirty-six months) is a diagnostic criterion (Young, Brewer, & Pattison, 2003). According to Trevarthen & Aitken, (2001) fifty percent of parents of children with suspected autism report a strong suspicion of abnormal development prior to the age of one. However, as Kalb asserts, most children will not even be seen by specializing clinicians until they have reached their second birthday with many of these waiting on the appropriate diagnosis until at least the age of three (2005). Further research suggests that anywhere between thirty-one and fifty-five percent of children with autistic disorder show at least some defining behavioral characteristics in the first year of life, and seventy-five to eighty-eight percent have some of these abnormal responses by the first two years of life (Young et al. 2003). For example, in this same data analysis conducted, it was determined that despite these qualitative and quantitative differences in development, the average age of diagnosis for children living in the United Kingdom in 1994 was not until forty-four months even when parents became first concerned about their child’s development at an average age of seventeen months (Young et al. 2003). Additional research has demonstrated a lag between twenty-four and thirty months from the first expression of apprehension by parents about their child’s development to the actual obtainment of a diagnosis.

Over the past decade, researchers have been working toward increasing the accuracy and sensitivity for the interpretation of minute behavioral characteristics in distinguishing autism from the typically developing population. As part of a ten year plan, the National Institute of Mental Health has set the goal of actually “reducing the frequency of autism in school-aged children through early diagnosis and intervention,” (Volkmar, Chawarska, & Klin, 2005). To do this, diagnostic criteria must be tweaked to accommodate the earliest observable behaviors of this disorder. The current definition outlined by the DSM-IV-TR was not researched for children under the age of three, and therefore, is clearly not applicable to toddlers and infants, particularly involving criteria for peer relationships and conversational skills (Klin, Charwarska, Paul, Rubin, Morgan, Wiesner, & Volkmar, 2004). As stated by Young et al. “Many of the behaviors included in [this] classification system relate to secondary behaviors often developed to compensate for underlying neurological deficits,” (2003). For example, stereotyped behaviors such as adherence to routines and rituals are much more common in older children and are rarely noted in children under two years of age. In this paper I will review the observed signs and symptomology reported by parents, observed during clinical diagnostics, and investigated within in the research setting of very young children with suspected autism spectrum disorders.

Parental Observations of Early Symptomology

Parents are often the first to become aware of behavioral deviations their children display from the expected norm, and as a result, these observations become critically vital for the development of early diagnostic tools in clinical evaluation. In a study conducted by Young et al. in 2003, the researcher found the mean age in which parents first notice abnormal developmental signs to be approximately 15. 1 months with a standard deviation of 11. 2 months. Ninety-five percent of these same parents noted anomalies in social development by the age of two. By their first birthdays, children have been noted by their parents to show patterns of extreme reactivity, either getting upset when a new toy or activity is presented or barely noticing this novelty at all. In case reports of classic autism, parents often report their babies have failed to coo or babble by their first birthday or words that they have developed inexplicably disappear (Kalb, 2005). A substantial proportion of others also exhibit repetitive behaviors characteristic of autism such as rocking back and forth or becoming fixated on an object, as well as unusual preoccupations and stereotypy emerging around twenty to thirty months (Kalb, 2005). Parents predominantly report that speech delays or worries about hearing are common concerns, and also may worry that their child is too well behaved or is highly irritable (Volkmar et al. 2005). Additionally, infants with autism may display limited eye contact, diminished social responsiveness, and show little facial expression. Children may be less likely to engage in motor or vocal imitation and are more likely to exhibit difficulties in regulating arousal levels and organizing sensory responses.

By thirty months, Volkmar et al. determined that differences from typical peers in areas of “both person-to-person behaviors (anticipatory postures, turn taking, intensity of eye contact)” and “behaviors in which an object is the focus of joint interest (joint attentional skills such as pointing to materials, following a point of another person, or giving objects),” (2005) have become readily apparent to many adults the children interact with, particularly parents. A minority of children with autism, however, (approximately one in five) show a normal course of development during infancy but begin to lose or regress in social and communication skills and instead manifest autistic symptoms of attention and preservative behavior between the ages of eighteen and thirty-six months (Osterling, Dawson, & Munson, 2002). This and other variations in the acquisition of symptomology of infants and toddlers with autism present significant difficulties in relying solely on parental observation, and thus require further evaluation and scientific study by trained clinicians.

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Early Detection of Autism in Infants and Toddlers (Part 2)

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Problems Associated with the Reliability of Parental Report of Early Symptoms

Due to the fact that parents spend the most time with their young children, both mother and father are considered to be in the best position logically to provide historical background information pertaining to developmental delays, skill regression, patterns of behavior, and behavioral difficulties shown by their children with suspected autism. Despite this remark, Goin & Myers determined that parent and family caregivers, as the most intimate observers of their own children, can deviate from objectivity in their recall of behaviors (2004). Moreover, due to the fact that twenty to forty percent of parents report a normal developmental course for their child up until an observed regression point, the examination of extremely early symptoms of infants later diagnosed with autism becomes limited to a smaller percent who have experienced consistently slow developmental milestones (Volkmar et al. 2005). Less frequently, evidence of autistic symptoms may be apparent in children under the age of three, and thus, compiled in data to determine the earliest diagnostic criteria, but these behaviors may become less obvious as the child matures. Finally, due to the fact that seventy-five percent of children with autism are mentally retarded, it is possible that the symptoms parents report in infants with autism are more so related to mental retardation and not at all autism specifically (Osterling et al. 2002). These weaknesses in terms of the reliability of parental report necessitate further investigation before an exact definition of autism can be developed in very early infants.

Overview of Early Symptomology as Assessed by Experienced Clinicians

Parents are often asked to participate in the systematic study of their children’s autistic behaviors by experienced researchers, even when direct observational reports are not requested in the form of parental interview as were described previously. With the technological revolution in the past decades in the United States, video cameras have become increasing accessible to families across the nation, and therefore, many parents inadvertently provide detailed documentation of their child’s development which can be utilized in research. According to Baranek in 1999, “retrospective video analysis has shown success as an ecologically valid methodological tool for earlier identification of children with various psychopathologies,” (220), and consequently can provide significant reliability and validity to parental report of behaviors.

Such is the case in an experiment conducted by Volkmar et al. (2005) where age-matched infants with autism were compared to typically developing infants, and differences in visual attention to social stimuli, smile frequency, vocalization, and object exploration engagement were examined. At twenty months of age, behaviors in facial expression, use of conventional gesture, and pointing to indicate interest were distinguishing criteria. In a follow-up retrospective video analysis between twelve and fifteen months later, groups were identified by social activities such as seeking shared enjoyment, social reciprocity, use of another person as a tool, interest in other children, and in communicative tasks, (e. g. attending to voice, pointing, using and understanding gesture). A similar study determined that by the age of three, finger mannerisms, attention to voice, pointing, and the use of other person’s body were able to correctly classify all subjects recruited in the experiment as either autistic or typically developing by examining videotaped interactions of young infants (Cox, Charman, Baron-Cohen, Drew, Klein, Baird, Swettenham, & Wheelwright, 1999). When first birthday party video tapes were viewed by Osterling & Dawson, a significant main effect of the diagnostic group was found for the category of social behavior, including looking at the face of another, seeking contact, imitating, and for the category of joint attention behaviors, pointing vague pointing, showing, as well, but not for the category of communicative behaviors of following directions and babbling (1994). In these videos, it was determined that the autistic subjects showed significantly more abnormal systems such as ear covering and self-stimulation, and as a result, ninety-one percent of all cases were correctly identified, providing solid evidence that professionals should thoroughly evaluate infantile use of eye contact, joint attention behaviors, and orientating to speech when determining appropriate diagnostic measures. Baranek found similar results when comparing infants with mentally retarded participants, in that those with autism exhibited poor visual attention, required more prompts to respond to their name, excessively mouthed objects, and more frequently showed aversion to social touch (1999). Furthermore, in a study aimed to characterize infants with autism spectrum disorders under the age of one, five behavior abnormalities were documented through retrospective video analysis which included poor social attention, lack of social smiling and appropriate facial expressions, hypotonia, and unstable attention (Werner, Dawson, Osterling, & Dinno, (2000).

Neurological Abnormalities as Diagnostic Criteria

To evaluate the significance of the previously reported behavioral characteristics found in various research studies, one must examine the neurological abnormalities occurring in the brains of those with autism. In determining the rationale for each observed behavior, it is important to establish that many core deficit behaviors can be linked to underlying neurological problems, whereas “secondary manifestations may be a product of an individual’s approach to coping with the disorder or other disorders that may coexist,” (Young et al. 2003), such as an intellectual disability. The cerebellum, medial temporal structures, and prefrontal cortex have been recognized as possible core regions of abnormality in autism spectrum disorders (Dawson, Meltzoff, Osterling, & Rinaldi, 1998), and perhaps the imaging process of an fMRI, MRI, or CT scan of the brain during infancy could diagnose children very early before symptoms appear, as brain differences would most likely precede observed behaviors. Further evidence supporting the notion that the medial temporal lobe of an individual’s brain is a primary player in the manifestation of autistic symptoms is found when lesions are made in the hippocampus and amygdala early in the development of monkeys.

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Early Detection of Autism in Infants and Toddlers (Part 3)

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These animal subjects subsequently displayed the persistent and severe cognitive and social impairments as well as stereotyped and self-stimulatory behaviors that are defining features of autism (Dawson et al. 1998). However, this discovery does contrast a recent case study evaluation of a young autistic girl by Dawson, Osterling, Meltzoff, and Kuhl which determined that in this specific child at one year of age, impairments did not exist in the domains of immediate memory of actions, working memory, and response inhibition linked to frontal lobe functioning as core features of autism (2000).

Head Circumference Growth as a Predictor of Autism

A recent discovery in human physiology and brain development research has led to the involvement of the Baby Sibs consortium in an effort to determine the earliest physical markers of autism, particularly abnormal head circumference growth (Kalb, 2005). It is presumed that if a significant increase in head growth during infancy is a risk factor for autism, the mechanism that triggers this onset of growth would actually precede any manifestation of the disorder. Post-mortem brain studies described by Lainhart suggest that brain abnormalities begin before birth in at least a percentage of cases of autism, and therefore, provide further evidence to this claim (2003). According to this same author, between birth and six to fourteen months of age, head circumference has been shown to increase at a significantly greater rate in children with autism than in an control or reference sample (Lainhart, 2003); fifty-nine percent of children with autism and only six percent of typically developing children show an increase of two or more standard deviations in head circumference during this developmental time. In another study of this same type with consistently similar results, it was determined that approximately ninety percent of two and three year old children had brain volumes larger than the healthy average in addition to abnormally large head circumferences (Courchesne, Carper, & Akshoomoff, 2003). In comparison to growth charts produced by the Center for Disease Control, average head size in recruited participants increased from the twenty-fifth percentile at birth to the eighty-four percentile in six to fourteen month old babies with autism spectrum disorders (Courchesne, et al. 2003), well before the typical onset of clinically significant behavioral symptoms. By late childhood, however, a follow-up study of participants between the ages of eight and forty-six yielded MRI results demonstrating that this extreme brain overgrowth is time limited and that eventually brain size between control and autistic individuals becomes approximately equal (Courchesne, et al. 2003). An additional study by Torrey, Dhavale, Lawlor, and Yolken discovered a pattern of significantly larger body weight and length in four month old infants later diagnosed with autism in comparison to control subjects, inferring that an abnormality in metabolism, growth factors, and hormone levels may indeed be the culprit (2004). Accelerated rate in head circumference growth is associated during infancy with overall increased brain volume and gray matter, as well as increased cerebral gray matter. Scientists have not come to a conclusive decision as to what exactly accounts for this increase, but theory suggests that the sudden growth could result from an over abundance of neuronal connections, which pruning fails to eliminate (Kalb, 2005).

The discovery that an overgrowth of head circumference occurs frequently during the early months of life for those later diagnosed with autism holds a very promising clinical role in the detection of this disorder. An inexpensive and noninvasive assessment technique, the tracking of brain size development may be a key to early diagnosis and consequently, even earlier intervention practices. If these results are further confirmed by subsequent studies, physicians and psychologists in the future may be able to quickly assess the risk for developing autism based on physical examination alone.

Communication Abnormalities: Nonverbal Gestures and Speech

Parents frequently express initial concern over their child’s speech and communication development, and thus this often becomes the first complaint of autism-related behavior that sends parents to seek out an evaluation. Although typically developing newborn infants possess immature brains, limited cognition, and weak bodies, it has been established that most are very motivated beyond an instinctual drive to attract parental care for immediate biological needs, and thus “to communicate intricately with the expressive forms and rhythms of interest and feeling displayed by other humans,” (Trevarthen & Aitken, 2001). This drive does not seem to be as strong in young children with autism as in most instances they communicate less frequently than matched developmentally delayed children. These children are also less likely to use contact and conventional gestures in requesting an object, but are, in fact, more likely to use unconventional gestures to make up for this deficit in such ways as manipulating the hand of the individual with whom they are interacting to the desired object (Volkmar et al. 2005). In an article by Werner et al. it was demonstrated that at two months of age, infants start to implement their vocalizations in a semi-social manner, and this distinction further aids in subsequent speech and language development (2000). From these results, one can determine that perhaps differences in these areas of vocalization between typically developing and impaired infants become evident by the age of twelve months. Also between the ages of six months to one year, meaningful differences become more pronounced in the communicative criteria, especially noted when these children develop a general lack of orientation toward verbalization and their own names. These differences, however, are often not utilized in evaluation of development and assessment for autism in individual children because most parents fail to recognize these communication difficulties until spoken language is more apparently delayed.

Within this same realm of communicative impairment, very young children with autism have also be distinguished in various studies from typically developing controls on the basis of response to name calling.

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Early Detection of Autism in Infants and Toddlers (Part 4)

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The process of learning to orient to one’s own name involves aspects of both social and communication domains as well as attention (Werner et al. 2000), and therefore, difficulties in responding to this specific vocalization indicates a broad range of dysfunction. Potentially a powerful estimate of impairment on the autism disorder spectrum, typically developing infants orient to their name being called approximately seventy-five percent of the time, whereas only thirty-seven percent of autistic infants oriented to their names between the ages of eight and ten months using retrospective home video footage in a study by Werner et al. (2000). Fewer differences were noted in terms of social response to name calling than in the Osterling and Dawson study (1994) of infants at one year of age, perhaps due to the fact that between nine and twelve months of age, many new behaviors are just beginning to develop. Although many complex social, emotional, and communicative behaviors emerge during the eight to nine months of life, skills within these categories do not begin to solidify until after the age of one.

Joint Attention as a Predictor for Social Impairment

The previous example of response to name calling in very young children also draws upon the difficulties that most autistic infants experience in their development of joint attention skills. During the first year of life, children with autism spectrum disorders may fail to follow a point and in many instances, will not gaze switch between interesting objects and an adult’s face or coordinate responses to emotional displays by an adult (Charman, Baron-Cohen, Swettenham, Cox, Baird, & Drew, 1997). Moreover, gaze monitoring in joint attention, which provides relevant information concerning interests and dangers in the environment, is essential for the active participation of social learning opportunities for all infants (Charwarska, Klin, & Volkmar, 2003). As such, deficits in spontaneous gaze monitoring are widely recognized at this point in current research as early signs of autism, although we are unaware of the neurological mechanisms to produce these problems. Kalb has determined through eye-tracking technology that when affected toddlers view the videos of their caregivers or other babies within the same nursery of which they are familiar, they tend to focus more on the individual’s mouth or an object located directly behind the individual than his or her eyes (2005). This finding was confirmed when Charwarska et al. demonstrated in 2003 that although face recognition improves with age in those with autism, older individuals employ feature-based rather than holistic strategies in face processing, and therefore, “recruit different neural substrates in face processing than their typical controls,” (1985).

In terms of pointing behavior, typically developing children will follow a pointed index finger when they have achieved a developmental level of twelve months old, but children with autism from the time they are born are significantly less likely, according to Young et al. to switch their gaze as a means of following a point by another individual (2003). Despite these findings, many infants with autism at two years of age show intact performance relative to typically developing controls in the area of nonsocial use of gaze to obtain information about objects and the environment surrounding them. Charman et al. suggest that these abilities remain intact in those with autism although social gaze is not initiated because they are not a feature of the central social communicative deficit in autism (1997). This discovery asserts that there may indeed be a key difference between the growth of social and nonsocial use of gaze in broad development of all infants.

Imitation and Pretend Play

Significant delays in the production of imitation in very young infants as well as pretend play schemes in their slightly older counterparts are important warning signs to monitor in developing criterion for early assessment strategies. Imitation by typically developing and developmentally delayed infants is not merely a superficial repetition of movements made by another person but is instead a complex tool for developing interpersonal relationships with parents (Trevarthen & Aitken, 2001). Trevarthen and Aitken continue in this explanation in stating, “[imitation] is, even for newborns, an emotionally charged mutual influence of motive states in which certain salient expressive actions of the other are identified and repeated to further an ongoing communication,” (2001). A study by Charman et al. produced confirming results in suggesting that although basic level of imitation is apparent in school-age children with autism, those under the age of twenty months show considerable difficulty and unresponsiveness in this area (1997). After the mastery of a significant degree of gross and fine motor skills has been obtain through imitation, most children will begin to establish play activities progressing from simple object exploration to functional object use and finally pretend play. Between the ages of nine and twelve months, however, distinguishable abnormalities become evident and progressively more deviant in those with autism spectrum disorder in comparison to typically developing peers (Volkmar et al. 2005). In this same study, it was determined that by the second birthday of many children with autism, differences in functional play abilities and routines are striking, particularly in terms of purposefulness, symbolism, and complexity (Volkmar et al. 2005). As functional play ability continues to be impeded throughout the early years of life, pretend play is further hindered, and thus, many children with autism do not begin to develop a concept of such imaginative behavior until they have been taught specific strategies and skills within an early intervention setting (Charman, Swettenham, Baron-Cohen, Cox, Baird, & Drew, 1998).

Implications of Early Diagnosis

Early detection and diagnosis of autism in young infants may be crucial to the future outcome of these individuals because early behavioral intervention has been shown to provide a substantial impact on the long-term prognosis (Osterling et al.

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Early Detection of Autism in Infants and Toddlers (Part 5)

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2002). According to Moore and Goodson, as a result of eligibility for participation in early intervention programs being limited to those with a formal documented diagnosis, early identification and accurate assessment have become increasing important (2003). Research suggests that intervention provided before the age of three and a half has a greater impact than does after the age of five. Therefore, if we could screen all children at birth for autism, clinicians and educational specialists could perhaps retrain the brain and consequentially avoid the development of afore mentioned social impairments that develop in subsequent months (Wetherby, Woods, Allen, Cleary, Dickinson, & Lord, 2004). In the past two months, the Center for Disease Control and Prevention has launched a $2. 5 million autism-awareness campaign known as “Learn the Signs. Act Early”, with an ambitious goal to educate all health-care providers and parents about the warning signs in this disorder so that early intervention can be implemented as soon as possible “to give kids with autism a shot at productive, satisfying, and emotionally connected lives,” (Kalb, 2005). With the identification of discrete and precise symptoms in very young infants within the scope of neurological abnormalities, atypical head growth fluctuations, communication delays, joint attention difficulties, and inabilities to attend to imitation and engage in pretend play, I believe that early intervention would become a possibility and thus make a significant impact for all children diagnosed with autism spectrum disorders.

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