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attention deficits in autism

In References on June 30, 2009 at 8:08 am

Attention function and dysfunction in autism. Allen & Courchesne (2001). 

 

Autistic individuals display a wide range of attentional abilities and deficits across the many domains of attention function, including selective, sustained, spatial, and shifting attention operations.

 

One being that attentional abnormality likely contribute to many of the clinical features of autism. For example, overly focused attention might contribute to the development of autistic person’s restricted pattern of interests or activities.

 

This is not to say that attentional impairment is a core deficit in this disorder. However, impairments of attention would be expected to place autistic children at a disadvantage when they are learning and developing other social, language and cognitive skills.

 

Thus, while attentional impairments surely result from abnormalities in brain function, certain arttentional strengths may have an abnormal physiological basis as well.

 

Selective attention:

In the early 1970s, Lovas and colleagues demonstrated that children with autism responded to a restricted environmental stimuli, suggesting that their attention was overly focused or “overselective”.

 

While clinical observation and empirical investigation both support the phenomenon of stimulus overselctiviry there exsit context in which an autistic person may actually appear to have an abnormally board focus of attention. For example, individuals with autism often tend to be more distractible than normal suggesting that their attention may in fact be underselective (Burack…)

 

Depending on the context, individuals with autism may have an abnormally narrow or abnormally broad focus of attention.

Whether an attentional focus is small and overselctive or inefficiently broad and underselctive may depend upon the presence of absence of paretal lobe abnormality.

 

Supernormal attention (Plaisted et al.)

Based on  the fact that autistic patients show poor generalization of learning from a training context to novel situations, they hypothesized autistic individuals must differ in their ability to process common versus unique features, unique features being processed well, while common features are processed poorly.

 

The ability to detect unique items is enhanced in autism.

 

Pascualvaca and colleagues (1998) have recently shown that autistic individuals are not impaired on a digit cancellation task, a common neuropsychological measure of focused or selective attention.

 

It is possible to elicit selective attention performance that is within normal limits or even superior to normal. Such a narrow spotlight of attention may actually be an advantage; an autistic individual with a narrow spotlight of attention will be less distracted by similar stimuli that fall outside of the spotlight.

 

A focus of attention varies among autistic individuals.

 

Sustained attention:

 

Studies support that notion that individuals with autism are not impaired in their ability to sustain attention. However, anyone who has experience working with autistic individuals will confirm that they do in fact have difficulty sustaining attention to certain tasks or activities.

 

Garreston, fein, and Waterhouse

Task difficulty did not differentially affect performance in autistic and normal control groups, which argues against a general impairment of sustained attention. Instead the only group difference was seen in the slow/social condition, wherein autistic children performed significantly poorer than normal controls and significantly poorer than their own performance in the tangible condition, suggesting an abnormal response to social reinforcement. Thus it may be the case that clinical reports of impaired maintenance of attention are due to motivational as opposed to ability-related factors.

 

While highlighting the importance of accounting for motivational factors when designing and interpreting neurobehavioral investigations of autism. Garretson et al,’ study also points to a possible abnormal interaction in autism between those neural systems mediating attention and those mediating motivation and the response to reward.

 

Spatial attention: the rapid orienting of attentional resources

 

Harris et al. –children with autism were on average 31% slower to detect validly cued targets preceded by short delays than those preceded by long delays.

 

The question of what role motor impairment has in the slowing responses.

 

Attention is an anticipatory operation; it is the enhancement of neural responsiveness in advance of relevant sensory information.

 

 

 

Shifting attention:

 

Casey et al. (1993) examined the continuous shifting of attentional set in

autistic savants. These authors used a visual discrimination task in which the attribute to which subjects had to attend in order to respond correctly was varied on a trial-by-trial basis.  Autistic and control subjects did not differ on this task in terms of accuracy or speed of response. It should be noted,

however, that subjects were given as much time as they needed to attend to the stimuli before determining the correct choice and executing a response. Therefore, the key aspect of the shift attention deficit, i.e. slowness of shifting, was not probed by this study.

 

In what may have been a demonstration of the implications of the shift attention deficit in a more ” world” setting, Swettenham et al. (63) examined the spontaneous selection and shifting of gaze direction during

a finite period of free play in very young children (i.e., approximately 20 months of age) suspected of having autism (as autism cannot be diagnosed definitively at this young age). Compared to normal and developmentally

delayed children, the children with probable autism demonstrated less spontaneous attention shifting overall. They were also more prone to shifting gaze between objects than between people. This latter finding may have

reflected avoidance of social stimuli or of more complex visual stimuli (63).

 

Pascualvaca and colleagues suggested that the

pattern of performance across the three tasks in their study

reflected autistic subjects’ ability to “shift their attention

continuously” and their difficulty shifting attention when

“already engaged in a particular activity.” As they pointed

out, this is consistent with the shift attention experiments

conducted in our laboratory, wherein subjects were

required to attend to one modality for a period of time

before they had to shift attention rapidly to a different

modality in order to detect target stimuli. As for the

discrepant performances on the two set-shifting tasks, this

appears to be consistent with the demonstration by

Garretson, Fein, and Waterhouse (76; see above) that

attention performance in autistic individuals benefits from

tangible but not from social reinforcement. That is, the

tangible visual and auditory effects of the computerized

task aided performance, while the standard social

reinforcement of the WCST (i.e., the examiner telling the

subject whether he is correct or incorrect) did not.

 

Tantible visual & auditory effects of the computerized task aided performance while the standard social reinforcement did not.

 

The Pascualvaca et al. study also demonstrated,

as in our shifting attention experiments, that autistic

individuals appear to have no difficulty shifting attention

when given adequate time. This is a very important point,

because the shifting attention findings have frequently been misinterpreted in both the autism and cerebellum literature.

The fact that rapid shifting of attention is impaired in

autism and in patients with lesions of the neocerebellum

does not mean that shifting attention is a core deficit of

autism, nor does it mean that shifting attention is a

fundamental function of the cerebellum. As eloquently

stated by Pascualvaca et al., the “deficit is not in shifting

attention per se, but may be secondary to difficulties in the

coordination and modulation of attentional resources, as

well as in the activating effects of motivation.” (64, p. 477).

Likewise, we suggest that the shifting attention task is

simply a useful probe of a more general impairment in the

rapid and accurate deployment or adjustment of neural

resources, be they motor, cognitive, or affective. In the

case of shifting attention, this impairment leads to

difficulties coordinating, modulating, and activating

attentional resources, and in the Pascualvaca et al. study,

perhaps motivational resources as well.

 

Summary

 

In sum, an examination of autistic performance

across a wide range of attentional operations reveals a

unique pattern of strengths and weaknesses in this

population. Individuals with autism tend to show an

abnormal distribution of attentional resources across space

that is a function of their parietal lobe defect. They are also

impaired when they must rapidly re-allocate their

attentional resources to new spatial locations or to new

target modalities, and a variety of evidence points to the

role of cerebellar abnormality in this deficit. When

attention is sustained on a single location (i.e., not

distributed across spatial locations or rapidly shifted

between locations or modalities), the performance of

autistic individuals is not impaired in most cases.

 

(rationale for computer ) 

The one

instance in which autistic subjects do perform abnormally

on such a task is the context in which performance is

manipulated by social reinforcement. In this case, autistic

subjects perform worse than normal controls. This

abnormal response to social reinforcement has been shown

in other contexts, and may reflect an abnormal interaction

between frontal regions subserving sustained attention and

limbic regions mediating the response to reward. However,

it is also possible that this is yet another reflection of

cerebellar abnormality in autism. The cerebellum is known

to be involved in association learning (65-69), and we have

proposed that it learns such associations so that it can

generate moment-to-moment predictions about which

neural systems will be needed in upcoming moments,

allowing it to effect the preparatory enhancement of neural

responsiveness in these systems. The cerebellum is known

to have rich connections with limbic circuits (70), and the

abnormal response to social reinforcement may reflect

cerebellar impairment in the learning of associations and

the subsequent provision of preparatory enhancement for

limbic regions responding to motivational information.

 

 

considered regarding the social reinforcement findings is

the possibility that the processing of socially reinforcing

information requires a very distracting shift of attention to a

person in a different location from the to-be-attended

stimuli. The distraction of responding to social reinforcers

and attempting to process such a complex (human) stimulus

would interrupt a task much more severely than would a

more “tangible” reinforcer such as a pretzel or a penny.

This would have less to do with motivation and more to do

with attention dysfunction. à computer use!

 

8.2. Implications for behavior and treatment

 

an autistic

child may learn to identify his father’s face not by the overall

appearance, but rather by some more focal feature (e.g., a

chipped tooth). Such limited recognition might be

detrimental to the natural formation of parent-child

attachment, a form of autistic socioemotional deficit that can

be particularly distressing to families of autistic children.

The inability to orient attention rapidly and

accurately to positions in space places autistic children at a

serious disadvantage when learning to comprehend the

complexities of the world. Slow and inaccurate orienting

of attention prevents one from taking in every element of

the continuous flow of information occurring in one’s

environment. The result is a fragmented sense of the world

which, among other things, will impede individuals from

learning about causal relationships and make the sharing of

attention with other individuals difficult if not impossible

 

Just as the inability to move attention rapidly and

accurately among spatial targets is detrimental to

development, so too is the inability to shift attention rapidly

and accurately between sensory modalities. The social

world is made up of a complex and ongoing sequence of

often-unpredictable visual, auditory, and tactile stimuli.

Unless one is capable of rapidly shifting attention among

these various modalities, information will surely be missed

and thus not learned by the developing child.

 

impairment in the autistic child’s ability to use

reward-related information to modulate attentional resources

can undermine many of the standard principles by which we

teach and learn. Therefore, successful interventions will

grow out of the careful planning of individualized programs

that capitalize on the attentional strengths and bypass the

weaknesses of individuals with autism.


Golstein, Johnson, & Minshew (2001).  Attentional processes in autism

 

Individuals with high functioning autism demonstrated that the major dysfunctions relative to controls are on those measures of attention that require cognitive flexibility or utilize psychomotor speed, as opposed to accuracy or span of apprehension. 

 

The evidence for impaired shifting of attention in autism appears to be associated with various aspects of complex information processing such as planning decision strategies or concept formation, and not with perceptual shifting of focus of the type that may be mediated by cerebellar function (Courchesne et al., 1993).

 

These findings indicate that the well-established cognitive deficits and their associated with autism are not the result of a failure to incorporate information or to sustain concentration or to resist distraction.

 

Thus, it appears that if individuals with autism do appear to have attentional deficits, they would be at the conceptual level, perhaps involving executive abilities and monitoring of novel information ( Ozonoff, 1995b; Ozonoff et al., 1994)

 

 

 

Attention deficits in autism

 

Daisy M. Pascualvaca,1,3 Bryan D. Fantie,1,2 Maria Papageorgiou,1 and Allan F. Mirsky1\

 

Attentional Capacities in Children with Autism: Is

There a General Deficit in Shifting Focus?

 

Journal of Autism and Developmental Disorders, Vol. 28, 467-478, 1998

 

Results of published studies suggest that children

with autism do not have any marked difficulties

in sustaining their focus of attention to

repetitive, predictable stimuli (Garretson, Fein, &

Waterhouse, 1990). In contrast, these children

often have difficulty shifting their focus of attention.

This difficulty has been demonstrated with

neuropsychological measures such as the Wisconsin

Card Sorting Test (WCST; Ozonoff, 1995;

Ozonoff, Pennington, & Rogers, 1991; Prior &

Hoffmann, 1990) as well as with reaction time

tasks (Courchesne, 1995; Courchesne, Akshoomoff,

Townsend, & Saitoh, 1995; Courchesne et al,

1994a, 1994b).

 

To clarify this deficit in shifting attention,

we devised two computerized tasks that

make demands upon two different aspects of shifting

attention. In the first task, the children had to

decide whether some feature of three targets was

either the same or different, and therefore, had to

change their focus of attention continuously between

the features of these stimuli. We designed

the second task to resemble the WCST whereby

the children had to shift their attention after having

focused on a specific target feature for some

time.

 

We were also interested in determining

whether the children’s difficulties in attention tests

were secondary to decreased motivation. There is

considerable evidence to indicate that tangible rewards

facilitate learning (Lovaas, 1977, 1993) and

attentional performance (Garretson et al., 1990) in

children with autism. Despite their susceptibility to

various reinforcement modalities, we hypothesized

that if these children had a real core deficit in attention,

increasing their motivation should not be

sufficient to compensate for such deficit.

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