Restricted Range of Interests Repetitive Behaviors and Stereotyped Patterns

Parenting Children With Asperger's And High-functioning Autism

Activities for Autistic Children

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1. Characteristics

In addition to salient disturbances in social behavior and language, individuals with autism may also exhibit abnormally intense preoccupations with one subject or activity, exhibit distress over changes in routines, insist on sameness in their environment, and engage in repetitive or ritualistic behaviors. For example, a child may exhibit signs of physical and emotional distress when a new piece of furniture is introduced into the home or if he or she is prevented from taking a traditional route up and down the aisles during grocery shopping. Still another child may center the majority of his or her activities around an obsessional object, such as toilets; he or she may draw pictures of them, talk about them, and flush all toilets in proximity as part of his or her daily life. Finally, others may repetitively bang a spoon or flap their hands for minutes, sometimes hours, during a single day. Such restricted and repetitive behavior may have particularly important developmental consequences for young children with this disorder because it may lead them to miss learning opportunities that fall outside their narrow scope of interest.

2. Brain-Behavior Findings

A novel environment offers an important opportunity for young children to explore and learn. However, when placed in a novel environment, autistic children typically fail to explore or explore only a fraction of available stimuli and this limited exploration is correlated with anatomic abnormality of cerebellar vermis lobules VI and VII (Fig. 3). Additionally, it appears that the more perseverative and stereotyped behavior shown by an autistic child, the greater anatomic abnormality of cerebellar vermis lobules VI and VII.

The correlation between deficits in exploratory behavior and cerebellar anatomic abnormality in autistic children is consistent with a large body of evidence from animal studies. Studies of mice with mutations causing cerebellar anatomic pathology show a reduced tendency to explore novel objects or environments and an increased tendency to move about perseveratively in testing environments. Hypoplasia of vermis lobules VI and VII has been specifically linked to abnormalities in exploratory behavior in two mutant animals, the GS guinea pig and the L1CAM knockout mouse. Potentially, defects in vermis lobules VI and VII may be sufficient to cause deficits in exploratory behavior. Nonetheless, since recent functional neuroimaging studies show that different cerebellar regions have different functional specializations, systematic studies will need to be conducted to learn whether and how various cerebellar regions, in addition to the vermis, play a role in deficits in exploratory behavior in autism. Studies of humans also indicate a role for the cerebellum in exploratory behavior. For instance, humans with acquired cere-bellar lesions are inefficient in exploring and learning possible solutions to novel visuospatial puzzles. Interestingly, PET studies show the human cerebellum to be active during mental or "imagined" exploration of a spatial configuration.

E. Attention 1. Characteristics

In addition to the severe social abnormalities noted by Kanner, descriptions of attentional disturbances are also prominent features of this first paper on autism. Kanner quotes a father's description of his autistic son: "He displayed an abstraction of mind which made him perfectly oblivious to everything about him ... and to get his attention almost requires one to break down a mental barrier between his inner consciousness and the outside world." The first experimental demonstration of overly focused attention or "stimulus overselectiv-ity'' in the autistic child was by Lovaas, Koegel, and Schreibman in the early 1970s; they showed that autistic children respond to a restricted range of environmental stimuli, suggesting they may miss critical social and nonsocial information. Impairments in attention are now known to be among the most consistently reported type of cognitive deficit in this disorder, whether observations come from parents, teachers, clinicians, or researchers. Also, among cognitive deficits in autism, attention deficits are one

Figure 3 (Top) T1-weighted magnetic resonance image showing midsagittal vermal lobules I-V and VI-VII for a 6-year-old autistic boy and his matched normal control. Note sulcal widening and hypoplasia in the autistic child in comparison to his matched control. (Bottom) Exploration map for the autistic and matched control subject (cerebella for each child shown in the top portion). Lines depict patterns of movement across the entire session. Note the varied exploration pattern of the normal child in comparison to the near absent exploration of the autistic child (reproduced with permission from Pierce and Courchesne, 2001. Evidence for a cerebellar role in reduced exploration and stereotyped behavior in autism. Biological Psychiatry 49, 655-664. Copyright 2001 Society of Biological Psychiatry).

Figure 3 (Top) T1-weighted magnetic resonance image showing midsagittal vermal lobules I-V and VI-VII for a 6-year-old autistic boy and his matched normal control. Note sulcal widening and hypoplasia in the autistic child in comparison to his matched control. (Bottom) Exploration map for the autistic and matched control subject (cerebella for each child shown in the top portion). Lines depict patterns of movement across the entire session. Note the varied exploration pattern of the normal child in comparison to the near absent exploration of the autistic child (reproduced with permission from Pierce and Courchesne, 2001. Evidence for a cerebellar role in reduced exploration and stereotyped behavior in autism. Biological Psychiatry 49, 655-664. Copyright 2001 Society of Biological Psychiatry).

of the most thoroughly examined by anatomical and functional neuroimaging technologies.

Attention abnormalities may contribute to clinical features in autism. As described earlier, a cardinal feature of autism is failure to engage in joint social attention and it is among the first striking deficits noticed in the autistic infant. In normal development, from joint social interactions between infants and mothers spring social knowledge and many higher cognitive, affective, and communicative functions. Tronick writes "successful regulation of joint interchanges ... results in normal [cognitive, affective, and social] development. The crucial element is that the infant and mother ... share the same focus of attention during the interaction." To do so, an infant must do more than focus his or her attention on a single, captivating aspect of an object or person: The infant must follow the rapid and unpredictable ebb and flow of human social activity, such as words, gestures, touching, postures, facial expressions, and actions on objects. By being able to smoothly, selectively, and rapidly adjust attention, the normal infant is able to combine, as a single entity in memory, the various and separate elements of a social situation. Abnormalities in adjusting attention would place the autistic child at a severe disadvantage in such rapidly changing social situations, and, in conjunction with severe abnormality in social and emotional systems, would add an additional major impediment to engaging effectively in joint social interchanges.

The regulation of attention is likewise important in the adaptive and active exploring of novel environ ments, acquiring a wide array of nonsocial knowledge, understanding causal relationships, appreciating the context of discrete events or stimuli, learning multi-modality sequential stimulus relationships, and observing relationships among different sensory attributes of objects, people, or spatial arrays. Moreover, the inability to attentionally anticipate or react in a flexible moment-to-moment manner may, in combination with other impairments, increase the autistic child's tendency to remain restricted in interests and activity.

As described next, behavioral performance during tasks requiring rapid and dynamic adjustments in the direction of attention is clearly impaired in autism, but performance during tasks requiring simple sustained or selective attention is often reported to be normal or even supernormal in some autistic patients. One interpretation is that these latter attention functions may be spared, reflecting once again the variability in which brain functions are affected and which are not. Recent knowledge gained from neuroimaging studies, however, has revealed previously unsuspected abnormality in neural functions that mediate these "normal" or "supernormal" attention performances and thereby raises the important issue of neural compensatory reactions in the face of developmental neural defect.

2. Brain-Behavior Findings

Studies of the brain bases of attention functions in autism provide a classic example that normal behavior does not necessarily indicate normal neural function.

a. Sustained and Selective Attention In simple tasks requiring an autistic child to sustain his or her attention to a stream of stimuli (e.g., pictures and shapes) presented one at a time in order to detect a target stimulus, performance can be near normal or normal. More interesting are reports that during some tasks requiring selective attention, such as detecting a specific target stimulus at one of many possible spatial locations, accuracy and speed of pressing a button to the target might even exceed normal. Such behavioral performance, however, belies the presence of underlying abnormal neurophysiological responses to these stimuli.

Thus, although autistic patients seem to be attending and behaviorally performing normally, the stream of stimuli and the targets either fail to elicit attention-related ERP brain responses, such as the Nd, N1, N270, or Nc, or elicit abnormally reduced responses, such as the auditory P3b. Often such brain responses are also atypically located. Moreover, like patients with acquired lesions of the cerebellum, autistic patients performing such attention tasks fail to produce a cerebellar-dependent neural response that may signal frontal cortex (Fig. 2). Also, in cerebellar and autistic patients the attention-related P3b response is abnormal. The P3b is cerebral cortical activity reflecting recognition of task-relevant information and updating of the stimulus context. Unlike the normal brain that produces this response reliably to each single target stimulus, in these patients the P3b response occurs intermittently and with highly variable amplitude and latency to target information. In fact, the challenge has been to find attention-related ERP brain responses that act normally in normally performing autistic patients.

The large disparity between the appearance of normal and intact behavioral performance and the reality of abnormal underlying neural functional activity remains to be experimentally explained. One possibility is that tasks used to date fail to be sufficiently demanding on the neural system supporting it, and properly demanding conditions would reveal behavior deficits consistent with abnormal neural activity. Such a possibility is lent credence by numerous examples of resolution of analogous disparities in studies of other types of patients. Another possibility is that systems mediating these particular attention functions are indeed spared, and the abnormal neural responses recording during such tasks reflect other aberrant operations whose responsibility is to effectively process the information that sustained attention mechanisms "bring in." A third possibility is that the abnormal neural responses reflect the result of successful compensatory brain reorganization in the face of developmental neural damage.

The first possibility is supported by evidence that adds an anatomic twist. Autistic patients with parietal volume loss appear to have a narrow, spotlight-like attention. Therefore, when their task is to detect target stimuli at only one specific location and ignore other nearby stimuli, they behaviorally respond faster to targets than normal, have shorter latency P3b responses to targets than normal, and have larger than normal visual sensory P1 responses to targets. Conversely, when their task is to make a difficult discrimination and they are led to expect it will occur in one location but instead the stimulus occurs in another, they are slower and more inaccurate, missing discrimination opportunities. For other autistic patients who do not have parietal volume loss, the reverse

Parietal Abnormal Parietal Normal

Figure 4 ERP evidence that autistic patients with parietal lobe volume loss have an extremely narrow ''spotlight'' of visual-spatial attention. Bar graphs are shown for autistic patients with and without parietal abnormalities and normal control subjects. The figure shows the P1 peak amplitude ERP response at occipital scalp sites to visual stimuli at an attended location (dark bar) compared to the P1 ERP responses at that location when attention was focused one, two, three, and four locations away (lighter bars in order left to right). Visual-spatial locations were separated by 2.7° of visual angle. Waveforms at the top showPl ERP responses at occipital sites to attended locations (solid line) compared to the average of all unattended (dashed line) locations (reproduced with permission from Townsend and Courchesne, 1994; Parietal damage and narrow ''spotlight'' spatial attention. J. Cog. Neurosci. 6, 220-232, Copyright 1994 by the Society for Neuroscience).

Parietal Abnormal Parietal Normal

Figure 4 ERP evidence that autistic patients with parietal lobe volume loss have an extremely narrow ''spotlight'' of visual-spatial attention. Bar graphs are shown for autistic patients with and without parietal abnormalities and normal control subjects. The figure shows the P1 peak amplitude ERP response at occipital scalp sites to visual stimuli at an attended location (dark bar) compared to the P1 ERP responses at that location when attention was focused one, two, three, and four locations away (lighter bars in order left to right). Visual-spatial locations were separated by 2.7° of visual angle. Waveforms at the top showPl ERP responses at occipital sites to attended locations (solid line) compared to the average of all unattended (dashed line) locations (reproduced with permission from Townsend and Courchesne, 1994; Parietal damage and narrow ''spotlight'' spatial attention. J. Cog. Neurosci. 6, 220-232, Copyright 1994 by the Society for Neuroscience).

is seen in these tasks with opposite demands for either narrowly or broadly focusing attention (Fig. 4).

Therefore, in autism, it may be that the underlying type and extent of anatomic defect interacts with selective attention demands, such that certain defects may allow or even facilitate successful performance under certain attention conditions but not under others, but entire neural attention functions such as selective or sustained attention are not uniformly spared per se.

b. Dynamic Regulation of Attention: Disengaging, Orienting, and Shifting Even though the autistic child sometimes seems able to sustain attention to something in his or her environment, he or she typically seems impaired in adjusting attention to follow unexpected and rapid changes in the source of information. Especially demanding are the unexpected and quick changes in verbal, gestural, postural, tactile, and facial cues that signal changes regarding where to direct attention in a stream of social information. Much information comes and goes (a momentary facial expression) or moves from place to place (different speakers in a room). Neuroimaging studies of normal subjects show that the rapid, dynamic regulation of attentional resources in demanding attention conditions involves a distributed neural network including the parietal and frontal lobes, thalamus, colliculus, and cerebellum. Multiple operations underlie such regulation utilizing different as well as overlapping neural components.

In autism, three such operations have been thoroughly studied via neuroimaging techniques. First, disengaging attention is a reactive operation implemented when important stimulus information unexpectedly occurs outside the immediate focus of attention. The parietal cortex is an essential neural component in this operation. Autistic patients with parietal cortical volume loss are slow to disengage attention, and the more loss, the slower the implementation of the disengagement so that in patients with the most loss, by the time attention has been disengaged information needed to make critical sensory discriminations has often already disappeared. ERP imaging shows that in patients with parietal cortical loss, there is an abnormally narrow distribution of visual-spatial attention such that neurophy-siological responses to stimuli at the center of attention are hypernormal in size while those outside this center are subnormal in size. This suggests that important stimuli unexpectedly occurring outside the immediate focus of attention are less able to rapidly and effectively trigger the disengage mechanisms. Therefore, in autism, parietal structural defects may impair the formation of effective attentional sensory maps of extrapersonal space, impair the operation of mechanisms that implement disengagement of attention, or both.

Second, when attention is not yet engaged and a stimulus occurs that signals the likely location of upcoming important information, attentional resources are normally immediately applied to that location in anticipation of the upcoming information. Successful anticipatory orienting increases the speed and accuracy of information processing of the upcoming information. Patients with cerebellar lesions from stroke or tumor and autistic patients are slow and inaccurate in such cued, anticipatory orienting of attention, and in the autistic child or adult the greater the cerebellar hypoplasia, the slower and more inaccurate the anticipatory orienting (Fig. 5). This effect has also been demonstrated for orienting to social and nonsocial stimuli.

Third, very often a particular stream of information will reach a point when it provides specific information or cues that explicitly direct or signal that attention is

A. SPEED B. ACCURACY C. CORRELATION

A. SPEED B. ACCURACY C. CORRELATION

grpl grp2 grpl grp2 Orienting Deficit

Figure 5 Orienting deficits (RT or accuracy at validly cued location at long cue-to-target delay and at short cue-to-target delay). A more negative orienting deficit indicates slower response or decreased accuracy to targets at cued locations when there is little time between cue and target onset. (A) Autism and cerebellar lesion subjects (cbls groups 1 and 2) showed significantly greater orienting deficits than normal control groups during the spatial detection task. (B) Autism and cerebellar lesion groups displayed significantly greater orienting deficits than normal controls during the spatial discrimination task. (C) Correlation of orienting with vermal lobules VI-VII in 22 normal, 10 autism, and 7 cerebellar lesion subjects. Vermal lobule VI-VII area measures in each subject were divided by that subject's intracranial brain volume (ICV) to control for overall brain size [reproduced with permission from Townsend, J., Courchesne, E., Singer-Harris, N., Covington, J., Westerfield, M., Lyden, P., Lowry, T. P., Press, G. A. (1999) Spatial attention deficits in patients with acquired or developmental cerebellar abnormality. J. Neuroscience 19, 5632-5642.]

grpl grp2 grpl grp2 Orienting Deficit

Figure 5 Orienting deficits (RT or accuracy at validly cued location at long cue-to-target delay and at short cue-to-target delay). A more negative orienting deficit indicates slower response or decreased accuracy to targets at cued locations when there is little time between cue and target onset. (A) Autism and cerebellar lesion subjects (cbls groups 1 and 2) showed significantly greater orienting deficits than normal control groups during the spatial detection task. (B) Autism and cerebellar lesion groups displayed significantly greater orienting deficits than normal controls during the spatial discrimination task. (C) Correlation of orienting with vermal lobules VI-VII in 22 normal, 10 autism, and 7 cerebellar lesion subjects. Vermal lobule VI-VII area measures in each subject were divided by that subject's intracranial brain volume (ICV) to control for overall brain size [reproduced with permission from Townsend, J., Courchesne, E., Singer-Harris, N., Covington, J., Westerfield, M., Lyden, P., Lowry, T. P., Press, G. A. (1999) Spatial attention deficits in patients with acquired or developmental cerebellar abnormality. J. Neuroscience 19, 5632-5642.]

now to be shifted to another source of information (e.g., such as when a mother is speaking to her child and then tells the child to look at something). In natural situations, such shifting of attention back and forth between different sources of information occurs often and rapidly, and fMRI studies show that cerebellar and parietal cortex are actively involved in normal people. It is unclear whether operations underlying such moment-to-moment and rapid shifts of attention overlap with the single instance of anticipatory orienting, but this seems likely based on fMRI experiments in normal people. Patients with cerebellar lesions from stroke or tumor and autistic patients are slow and inaccurate in shifting of attention rapidly and frequently back and forth between very disparate (e.g., sights and sounds) sources of information. Therefore, when cerebellar or autistic patients have little time to implement a shift, they often miss detecting important information appearing at the new source of attention and their neurophysiological responses confirm that they failed to mentally register that important information. Stimuli that explicitly signal the need to immediately shift attention elicit an "Sd" brain response, but this is abnormally small or absent in cerebellar or autistic patients.

Although slow and inaccurate in anticipatory orienting and shifting of attention, cerebellar and autistic patients eventually do adjust the direction of their attention if given sufficient time, according to both behavioral and ERP imaging evidence. Thus, it has been a misconception among some researchers that autistic patients are incapable of orienting or shifting attention. Tests requiring conscious and effortful judgments about when to change or shift mental set, such as the Wisconsin Card Sorting Task, are not tests of the cerebellar or parietal involvement in the capacity to make immediate (in the hundreds of milliseconds range) and accurate adjustments in the direction of attention signaled by unexpected stimuli occurring within an attended stream of information. Rather, the successful ability to make such extremely quick and accurate anticipatory attentional adjustments must depend to a large extent on prior learning of associations between the signal to shift and the appearance of subsequent important information. Such automatic and swift neural actions are likely the product of well-known cerebellar association learning mechanisms. Such mechanisms may first learn predictive associations between successive events and then use that information by sending, on a moment-to-moment basis, preparatory signals to appropriate brain systems.

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Funny Wiring Autism

Funny Wiring Autism

Autism is a developmental disorder that manifests itself in early childhood and affects the functioning of the brain, primarily in the areas of social interaction and communication. Children with autism look like other children but do not play or behave like other children. They must struggle daily to cope and connect with the world around them.

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  • gaudenzia
    What us a restricted range of interests?
    3 years ago

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