Development and Autism Part 4

Toddlerhood: Creating Predictability and Agency in an Atypical System

As infants grow into toddlerhood their atypical autistic symptoms become even more pronounced and visible. While the earliest diagnoses are not commonly made before the third year, some medical institutions and diagnostic procedures will make preliminary diagnoses later in the second year should the symptoms and their severity be convincing enough (Landa, Holman, & Garrett-Mayer, 2007). Numerous studies point out that the earlier diagnoses can be administered the earlier interventions can be implemented and the more likely it is to reduce or even reverse autistic symptoms (Landa et al., 2007; Sheinkopf & Siegel, 1998). A widespread international effort across several academic and scientific communities is thus made to discover methods and early markers that indicate atypical development causing autism.

Because autism is proposed to be a neurological disorder, researchers have accomplished ways to analyze autistic brains at young ages with sleep fMRIs. Several neurological differences have been identified when looking at both high- and low-risk toddlers between 12 and 48 months (Pierce, 2011). Researchers read bedtime stories to sleeping high- and low-risk toddlers and children while measuring their brain activation responses. As opposed to the left hemispheric activation predominantly found in typically developing infants and children, high-risk subjects demonstrated right hemispheric activation.

Pierce (2011) also found further distinguishing results when measuring sleep brain activity in response to socially-orienting verbalizations, e.g. imperative calls involving the subject’s name, or non-social environmental sounds. High-risk toddlers and children seem to show a similar right-hemisphere dominance response to the social stimuli while the left superior temporal gyrus displayed an atypical response to the non-social stimuli (Pierce, 2011). Because early language-sensitive structures are found to inhabit left hemispheres in typical brains, these activation patterns in atypical brains suggests either a neural lack or misplacement of language specialization.

Wernicke’s area, located on the left superior temporal gyrus, typically shows early sensitivity to language (Geschwind, 1970; Kim, Relkin, Lee, & Hirsch, 1997; Kuhl, 2004). The right hemisphere has been associated with the more subtle aspects of communication such as gestures, facial expressions, gaze following, pragmatics and prosodic understanding (Abusamra, Côté, Joanette, & Ferreres, 2009). If autistic brains display right hemisphere dominance in response to language, which would typically elicit left hemisphere dominance, it is conceivable that the right brain is being used in a way that crowds out networks needed to encode complex communicative subtleties. Structurally, using the right hemisphere to encode gross language input may not be the most efficient way to form the necessary neural connections (Pierce, 2011). When considering that certain neural networks have to be established firmly first in order for others to arise, the atypical location of these neural structures may indicate an asynchronous development of the hemispheres in response to social communication (Smyser et al., 2010).

A further physiological atypicality found in many autistic individuals involves sleep hygiene and impairments. Many autistic children demonstrate marked inabilities to initiate and maintain sleep, to sleep restfully or with others, and to wake up the next morning (Jeste, 2011). Sleep deprivation naturally has harmful consequences on memory, learning and overall cognition (Boonstra, Stins, Daffertshofer, & Beek, 2007). Sleep studies on autistic individuals has shown that autistic sleep deprivation is characterized by reduced REM sleep, reduced rapid eye movements during REM sleep, greater slow-wave sleep, shorter sleep periods, and frequent intermittent awakenings (Jeste, 2011).

REM sleep is important for cognitive development as it creates decreased activity in the frontal cortex. The frontal cortex is often associated with creativity and cognitive flexibility in young individuals, but with integration of knowledge in adults (Thompson-Schill, Ramscar, & Chrysikou, 2009). As with infancy, high-risk toddlers between 1 and 2 years of age display early brain overgrowth characterized by increased synaptogenesis and overconnectivity. These toddlers usually show an overgrowth in white matter showcasing an overly connected prefrontal cortex and an underdeveloped connectivity to the rest of the brain (Courchesne & Pierce, 2005).

Interestingly, in high-risk toddlers and autistic children, the prefrontal cortex resembles that of an adult rather than that of an age-matched typically developing child, which leads researchers to believe that their prefrontal cortex matures more quickly (Thompson-Schill et al., 2009). A mature prefrontal cortex may inhibit certain levels of creativity simply because it integrates prior beliefs, ideas and expectations into any given task more so than an immature prefrontal cortex. The extent to which creativity may be impaired in individuals with mature prefrontal corteces is thought to be demonstrated in the fact that typical children do not show difficulties using novel objects creatively, whereas adults and autistic children do (Bruckner & Yoder, 2007; Wulff, 1985).

While REM sleep suppresses frontal lobe, and thus prefrontal cortex, activity both in typical children and adults, thus potentially allowing for nonsensical, not strictly experience-based thoughts, i.e., dreams, its overall shortage in autistic children may underlie their inability to behave and think creatively both while awake and asleep. Dream analyses of children with autism are difficult to administer as many autistic individuals show difficulties describing their thoughts, feelings, and experiences, but would be an interesting and potentially useful investigation.

The frontal lobes, specifically the prefrontal cortex, are one of the most and earliest dopamine-sensitive regions in the brain (Diamond & Baddeley, 1996). Given that autistic individuals show both dopaminergic overactivity and a mature prefrontal cortex early on, the two symptoms may be related. Rigidness in problem-solving and overly integrative thinking paired with highly active dopamine systems may lead to an inability to cope and thus a tendency to withdraw prematurely from complex situations or environments. This possibility is strengthened by the finding that out of all the maladaptive behaviors typically seen in autism, social withdrawal is the only tendency that does not correlate with lower IQ levels in individuals with autism (Anderson, Maye, & Lord, 2011).

Further, a prematurely mature prefrontal cortex may not be conducive to the kinds of developmental trajectories that are necessary to acquire certain skills. For example, a child that is too able to integrate too many different bits of information may become overwhelmed with unnecessary information thus confusing noise with signal and vice versa. If the goal is to learn how to grab a cup with a handle versus one without, it may be more effective cognitively for the child to simply deal solely with the cup with the handle, rather than to integrate its knowledge about all kinds of cups and how they vary across situations, environments and circumstances. Thus, an overly integrative prefrontal cortex may inhibit earliest forms of straightforward learning. This is apparent in Stroop studies, in which adults are more affected by interference and mismatching due to prior acquisition and integration of knowledge than typical children (Girelli, Lucangeli, & Butterworth, 2000). A similar cognitive pattern may be at play in autistic toddlers and children.

This is an interesting contrast to the potential underdeveloped cerebellum in autistic individuals, which would prohibit proper sensory and perceptual integration. An organism, which is structured in a way that overstimulates cognitive integration and understimulates sensory and perceptual integration, may be a highly confusing and disorienting one. More importantly, most caretakers and caretaking cultures are not structured to facilitate such an organism. Rather it is assumed that sensory and perceptual integration can be achieved first followed by cognitive information integration.

One aspect of child development that has gained a lot of scientific attention in autism research is that of motor development. Delayed and deficient motor development seems to be a uniting theme across all levels of autism severity. Motor behaviors in autism have been shown to develop atypically across many domains. The earliest descriptions of autism by Kanner describe failures in autistic toddlers to adjust their postures in anticipation to being picked up (Kanner, 1943). This motor deficiency may have to do with both a motoric inability but also an attempt to avoid overwhelming social contact.

Researchers have found balance and posture deficits in infants, which may be linked to the abnormal development of the cerebellum during prenatal life. Additionally, a delayed acquisition of typical crawling and walking, general difficulties performing age-appropriate fine and gross motor skills, and repetitive self-stimulating movements, usually centered around the hands and fingers have been documented in autistic toddlers (Jeste, 2011).

Stereotyped repetitions of movement are effective predictors of the severity of autism, and seem to indicate certain neurological abnormalities (Jeste, 2011). Repetitious behavior in autistic toddlers may fulfill a form of stimulation that cannot be acquired through social interactions. When typically developing children interact socially, stimulation occurs multi-modally, occupying auditory, visual, and somatosensory modalities. Since autistic children may be unable to integrate these stimuli as effectively or may feel overwhelmed by their cognitive integration process, they go to great lengths to avoid such interactions. Instead, they seek stimulation from more predictable, uni-modal sources.

Many autistic children are attracted to repetitious events such as wheels turning, fans blowing, or simple mobiles (Ozonoff et al., 2008). One socially relevant example may be self-generated repetitious movement. These events are fully controlled by the individual and regulatable in a potentially comforting manner. Additionally, since they are so rigid in their production, there are no surprises making the activity highly predictable and thus perhaps more comprehensible. Interestingly, the severity of repetitious behaviors has been correlated with lower IQ levels and cognitive abilities (Jeste, 2011).

An aspect that usually correlates with high levels of repetitive, stereotypic, and rigid behavior is abnormal sensory integration and processing (Dawson & Watling, 2000). Both symptoms may tie back to the abnormal formation of the cerebellum during prenatal development. Cerebellar malformations as caused by early pathologies or maternal stress could potentially impede the development of neural structures enabling sensory integration and processing and balance. Being unable to integrate sensory information properly in addition to lacking a sense of postural balance could make repetitive movements all the more rewarding as they usually center around distinct, isolated, and predictable sensations without much readjusting or realigning of body posture. The toddler, through self-generated, repetitive motions, thus “approaches” the kinds of sequences of events that produce a sense of agency and predictability.

Another interpretation for this self-stimulatory behavior may have to do with the atypical manner in which children with autism learn about themselves and acquire a general sense of self. Typically developing children learn a lot of self-related agency and action through interactions with other humans (Gergely & Watson, 1999). Infants first learn to detect contingencies based on others’ actions and their own around the same time regardless of their motoric advancements (Watson, 1966). They are, however, better able to assess others’ goal-directed behaviors if they are able to motorically produce the same behaviors (Bertenthal, 1996; Springer et al., 2011). This understanding is presumed to play a large role in understanding both the self but also others’ states of minds and intentions. A child who is unable to perform certain motoric actions, or one who is generally overwhelmed by social interactions, will be less likely to learn about their agency in complex situations (Toth et al., 2007). Therefore, a way to compensate for this deficit may be to produce events within their own predictable sphere in which they can both act and react with a contained set of possible outcomes.

Repetitious behaviors may also indicate the inability to flexibly and non-rigidly experiment with motor capacities. During typical development, an important balance is acquired between variation and variability when performing and training motor movements (Hadders-Algra, 2010). Motor development becomes hampered when variation occurs in a non-systematic manner, where levels of variability occur unpredictably. In stereotypic repetitions, variation does occur in terms of the overall repeated behaviors. Individuals showcasing these movements can show a great range in overall motions they use repeatedly. What lacks is the variability from repetition to repetition. The behaviors are produced as exact replicas of each other not to attain a functional goal but to attain a sensory stimulation. In typically developing toddlers, variability allows for experimentation with different movements in order to acquire certain fine and gross motor skills. When this ability to vary is deficient, toddlers are presumed not to acquire motor skills as easily (Jeste, 2011).

Variability can also be detrimental when it occurs at a level that goes beyond experimentation and acquisition. Motor behaviors that demonstrate atypical amounts of variability are seen in many autistic children’s crawling, gait and walking styles (Jeste, 2011). These are examples in which children misuse the needed levels of variability and variation when performing actions. Walking and gait are most efficiently undergone when following a systematic pattern (Hadders-Algra, 2010; Thelen & Smith, 1998). Because children with autism often do not follow typical developmental trajectories, they may not be able to arrive at the same motor conclusions when attempting to walk.

The autistic avoidance of social contact becomes more measurable in toddlerhood when social behaviors typically manifest and solidify. A study comparing play behaviors in typical toddlers and those at risk found parental reports of social differences at as early as 13 months (Toth et al., 2007). The study demonstrated those at risk to show decreased expressive and receptive language, lower IQ, less adaptive behavior and fewer social communication skills. These toddlers used fewer words and distal gestures, and responded less often with social smiles (Toth et al., 2007). The high-risk toddlers may have learned these characteristics from their siblings with whom they presumably interact on a daily basis. If their closest peers perform such behaviors during social interactions, it may lay out the groundwork for why many siblings of autistic children are in fact at a high risk of developing the same symptoms.

On the other hand, similar findings have been found in first-born toddlers between 18 and 24 months later to be diagnosed with autism (Shumway & Wetherby, 2009). After qualifying as potentially developmentally delayed, these individuals were compared to typically developing toddlers. They showed clear differences and deficits in overall communication, specifically in joint attentions acts and deictic gestures. Those toddlers who were able to communicate using joint attention also showed coordinated vocalizations, eye gazes, and appropriate gestures (Shumway & Wetherby, 2009). Aside from its distinguishing findings, this study points out the developmental importance of joint attention abilities in toddlerhood.

Typically developing toddlers demonstrate social understanding of deictic gestures between 12 and 24 months, and can use them in social situations to initiate joint attention. In a study analyzing how pointing relates to social communication, typical toddlers were shown to go from looking to their social partner first and then pointing at 12 to 19 months to looking to their social partner after completing the pointing gesture at 20 to 24 months (Franco, Perucchini, & March, 2009).

Presumably, the changing factor that allows toddlers to develop pointing gestures without looking first to their partners involves the development of motoric coordination. This transition may represent the necessary stages an infant must go through to initiate joint attention. First, it must learn that there is another social entity with whom it can share attention. Then, it must identify that social entity (the initial look to the partner). Finally, it must redirect its attention to the original area of interest and using hand-eye coordination and fine motor skills to extend its finger toward that area. The transition of looking after pointing demonstrates that the toddler has already learned that other social entities exist and can be redirected in their attention. Thus, the toddler does not need to identify its partner before pointing. The toddler can point and turn to its partner while keeping its arm and finger steady using previously undeveloped balance and posture control. This final turn to the partner acts now as more of an extrinsic attention getter and maintainer rather than an intrinsic identification process.

The joint attention deficits in autistic and high-risk infants bleed into toddlerhood, where affected individuals show immense deficits in initiating joint attention for affective and social reasons (Schertz & Odom, 2006). Part of the problem is their disinterest in or aversion to social entities. Their rates of social identification and social referencing are overall lower than those seen in typically developing children (R. L. Koegel, Vernon, & Koegel, 2009). On top of that, their fine motor skills, balance and posture are commonly deficient making it more difficult for them to point but also to shift gazes while maintaining the attention-getting point (Dawson & Watling, 2000; Iverson & Wozniak, 2006). Not only are these toddlers less inclined to share social attention for several reasons, but they may simply be unable to do so motorically during a time in which joint attention bears the most scaffolding value.

In order to tackle the aversion aspect of joint attention and general social interactions in autistic toddlers, various studies have tried to tap into the kinds of stimuli autistic toddlers find rewarding. Once identified many experimenters attempt to pair these elements with social stimuli. In a small study autistic toddlers were to utter the appropriate word and then were given either a preferred object or the preferred object accompanied by the interaction with a social partner (R. L. Koegel et al., 2009). The study found that interactions surrounding a preferred object elicited many more socially-oriented behaviors in these toddlers than with non-preferred objects or without social partner involvement. Here, the importance of both the reward system but also the toddler’s preferences guiding interactions becomes nearly indisputable.

Even before language has formed to be fully functional, joint attention can structure interactions in a way that allows for many instances of social learning and communicative exchange. Individuals who miss out on these interactions will face crucial deficits in naturally occurring lessons concerning object labeling, social affect, reciprocation, anticipation, communicative contingencies, and possibly theory of mind (Schertz & Odom, 2006). For example, toddlers later diagnosed with autism do not seem to engage in the kinds of social and symbolic play seen in typically developing children (Toth et al., 2007; Wulff, 1985). These toddlers will be seen repeating actions beyond experimentation, and focusing exclusively on the objects without seeking and attaining social feedback (Adamson, Deckner, & Bakeman, 2009). Along the same lines, these toddlers also lack the ability to imitate their playmates in the kinds of games that call for coordinative imitation (Carpenter, Tomasello, & Striano, 2005).

There is a potential link between missing out on these learning opportunities and feeling easily overwhelmed by multi-sensory situations often involving a social component. If there is no way for an individual to predict the sequences of events, and no way to interpret the occurrences using social or anticipatory understanding, then life must seem extremely disorienting. This may be why researchers and caretakers begin to see self-mutilating behaviors emerge at a time in which joint attention would typically solidify. Specifically, researchers have found abnormal sensory processing and integration to be the strongest predictor of self-injurious behaviors in young individuals with autism (Duerden et al., 2012).

In general, toddlers later diagnosed with autism are notoriously bad at regulating their emotions (S. D. Mayes, Calhoun, Mayes, & Molitoris, 2011). It is possible that being unable to share affective gazes and smiles with social partners stunts the ability to share or even process emotions in a non-destructive manner. Likewise, if a young individual is unable to detect the relationship between its own crying and the appearance of a caretaker, or worse, if the appearance of the caretaker exacerbates whatever stress the individual is experiencing, then typical first instances of emotion regulation may prove to be futile.

These atypicalities would also affect attachment styles that would have formed by this age. Caretakers often report a lack of attachment felt between themselves and their atypical toddler (Dawson, Hill, Spencer, & Galpert, 2012; Hoppes & Harris, 1990). What may have started out with the typical amount of cuddling and holding seems to decrease over the course of the first year representing a definite reduction by the second year of life (Schertz & Robb, 2006).

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Continue onto Part 5 of the Series Development and Autism