ASD and Gastro-intestinal Factors
There has arisen, over recent years, an interest in the possibility of an association between the symptoms of ASD and gastro-intestinal problems, and between such symptoms and nutritional and dietary status or habits of the individuals concerned.
The review completed by Erickson et al (2005) begins with an acknowledgement of how the history of autism and ASD has been marked by a series of supposed “breakthroughs” with perceived implications for significant steps towards averting the onset of the condition or significant reductions in the observable signs and symptoms and improved functioning.
However, it has all too often been found that the claims do not stand up to rigorous testing and that the evidence is anecdotal and of limited generalisability.
The field of gastro-enterology may prove a case in point where well-designed research is scarce and there remains a challenge in differentiating theory from evidence and uncontrolled observations from hard data.
Their review involved a search through published papers (n = 73) identified by key words pertaining to autism, gastro-intestinal functioning, bowel disorder, diet, and nutrition.
In respect of diet and nutrition, Erickson et al note that repetitive behaviours and an insistence upon unchanging routines (core features of ASD) may have a negative impact upon the individual’s willingness to take in a balanced diet and to benefit from a balanced diet.
Relevant studies have shown that, typically, children with autism have a higher prevalence of selectivity when it comes to what they will eat, often based upon food category or texture.
Other studies have examined the nutritional status of children with autism, including the prevalence of taking in non-food items (pica).
In one case, the autistic sample was found to have an adequate intake of all nutrients, perhaps even a greater intake and an increased calorie intake compared to controls, but a higher incidence of pica was also noted on the basis of parental reports.
In another case, the focus of the investigation was nutrient and mineral intake as measured via hair samples, but the only difference between the autistic sample and controls was the lower cadmium level in the children with ASD and it was not clear if this had any clinical significance.
In a further (but early) study, the sample of children with ASD were found to have generally higher blood lead levels than control children or children with severe but non-autistic (psychotic) conditions; but none of the children had any episodes of acute lead ingestion or had been suspected of having “clinically” high lead levels.
In summarising this area, the authors suggest that a consensus among reports has it that those children with ASD whose nutritional status has been assessed have an overall adequate diet.
While it is true that such children tend to have increased food selectivity, the data suggest that this does not seem to lead to poor nutritional status or actual malnutrition.
Food intolerance or allergy has been investigated, notably the possibility of gluten sensitivity or the existence of a variant of celiac disease.
In respect of this latter, one major study found no evidence for such concerns; and a second study evaluated a large sample of children who were diagnosed with gluten-sensitive celiac problems but found no signs or symptoms of autistic or autistic-like problems.
Meanwhile, food intolerance (such as a reaction to dairy products) does appear more common among children with ASD than among controls; but no evidence has been identified for associated gastro-intestinal problems nor any clear evidence for the benefits (or lack of benefits) of adopting a special diet.
In summary, the authors highlight the mixed results reported in studies which have examined the response of children with autism to dietary proteins (and they cite one study where children were reported to be showing improvement by following an elimination diet but who demonstrated no reason why they should need such a diet).
They accept that some children with autism may well have dietary protein intolerance of one kind or another, but there is no evidence that this kind of intolerance is consistently or significantly more prevalent in the autistic population.
A review of data concerning gastro-intestinal tract anomalies comes to a similarly equivocal conclusion in that, for example, there does appear to be a heightened prevalence among children with ASD of problems such as reflux esophagitis or chronic gastritis or colonic lymphoid nodular hyperplasia (greater cell density in the tissue) but there are common methodological shortcomings such as a lack of control groups or sample biases in that the children with ASD who were assessed were not representative of such children generally but had been referred to a specialist clinic because of gastro-intestinal problems.
In other words, there may be some issue, such as the possibility of some autoimmune anomaly, but the existing “level” of evidence precludes any such clear conclusions.
The authors conclude by referring to the ongoing need to delineate the inflammatory changes found in children with autism from those associated with inflammatory bowel disease or those observed in normally-developing children who show symptoms of lymphoid nodular hyperplasia.
The focus of attention would appear necessarily to be upon the immune cell characteristics within the gut lining.
However, the clinical significance of the findings of gut pathologies among children with ASD remains uncertain, but with the possibility of there being functional differences in a subsample of children with ASD who demonstrate these pathologies.
The authors refer to the problems of dependence upon parental reports or medical records, while noting a recent study (Kuddo and Nelson 2003) which concludes that
“ no report exists that describes the prevalence of gastrointestinal disorders in a representative group of children with a concurrent diagnosis of autism and in appropriate controls ”.
In their discussion, Erickson et al pose the question whether the “triad” of core defining domains of ASD should be augmented by a fourth domain, namely gastrointestinal-related ASD.
They suggest that, currently, this would not be reasonable given that available evidence concerning children with ASD fails to put the data into perspective with regard to typical children or to determine whether ASD itself predisposes children to increased gastrointestinal problems.
If a child with ASD presents with such problems, they should be subject to “standard” evaluation and treatment given that there is no real evidence that specific gastrointestinal problems are linked to ASD. However, there remains scope for further investigations of these problems in children with ASD, for controlled dietary trials, and for exploring the “ gut-brain axis ”.
The study by Landa and Goldberg (2005) examined language/social skills and executive performance in a sample of high functioning children with ASD, based upon their observation that such children typically have verbal and non-verbal impairments, but that the pattern of such impairments is not clear and there may well be inconsistencies and mixed abilities across individuals.
For example, some aspects of grammatical development or syntax understanding may be impaired to various degrees.
Similarly, there may be considerable variation in respect of semantics.
Meanwhile, evidence suggests that the high functioning individuals with ASD are likely to have relative strengths in vocabulary knowledge but use of language may still show weaknesses when it comes to managing and processing abstract language or ambiguities.
The authors contend that the impairments in language skills may be linked to difficulties with executive function (defined as the ability to organise and maintain appropriate problem solving behaviours to attain a given goal). Component skills of executive functioning are held to include planning, flexibility of operating (shifting the mind set according to ongoing outcomes) and working memory.
An implication is that these core executive weaknesses characteristic of ASD may underlie the communication and social impairments which are also characteristic.
The question raised by Landa and Goldgberg is about the precise level or nature of executive functioning skills in the higher functioning individuals. Planning and set shifting have been most implicated, but they note some existing evidence that the planning component is not significantly impaired, and they have identified conflicting reports whether the set-shifting and working memory capacities are impaired or not.
Such a question is relevant in seeking to understand the social and communicative behaviours of individuals with ASD given that executive dysfunction would impact upon the ability to plan salient contributions to discussions or conversations, to shift from one meaning of a word or phrase to another in the case of some ambiguities, and to hold relevant bits of information in mind while grasping the gist of what others are saying and drawing appropriate inferences.
Joint attention may be threatened as well as the capacity to understand and predict another person’s perspectives, beliefs, and likely behaviour.
The aim of the authors’ own study was to explore the hypotheses that individuals with high functioning ASD would show weaknesses in tasks involving the formulation of complex sentences, assessing abstract language, and planning or set shifting.
The target sample was a group of children with ASD, aged between 7 and 17 and with a mean age of 11 years, who were set a range of tasks whose outcomes were compared against measures of IQ, language skill, and executive performance.
The findings provided some but not full support for the hypotheses given that the individuals in the target sample showed mixed performance indicative of a range of language and executive functions from typical for the age and ability to significantly impaired.
Compared to the control group, the individuals with high functioning ASD performed more poorly on tasks involving sentence formulation, comprehension of figures of speech, spatial working memory, and planning.
Interestingly, the ASD group commonly showed a better performance in those tasks requiring some flexibility and the capacity to shift their “set”.
Expressive grammar and comprehension of abstract language (such as figures of speech) were impaired despite adequate IQ scores, suggesting that while there might be a correlation between language and verbal IQ, the association was not complete and a child could still show weaknesses in generating more complex sentences or in the use and understanding of non-literal language or in coping with nuances.
Thus, while surface indications indicate language competence, the ability to cope with more subtle communications and full grammatical awareness may still be lacking.
Similarly, working memory difficulties were noted, especially in those tasks involving the greatest memory loads, and there was some speculation that a tendency towards perseveration could also be inhibiting performance (and that the presence of absence of this factor might be the means of reconciling inconsistencies among existing studies of working memory).
Planning weaknesses appeared less to do with the difficulty per se of the tasks and more to do with efficiency of processing …. the target sample solved fewer problems in the minimum number of moves. It was suggested that this result supported the view that children with autism, even with good IQ scores, cannot keep up with their age peers in frontally-mediated task performance as the frontal lobes mature.
The authors concluded that the kinds of inconsistencies observed mean that there is no real support for the view that executive functioning is an area of core deficit in autism which could give rise to the social and language impairments.
They further underline their observed lack of clear correlations among the three areas of IQ, executive functioning, and language (even if one can observe a correlation between IQ and language, or between IQ and executive functioning only in a memory task); and they believe that the apparent lack of relationship between intelligence and general executive functioning is puzzling and worthy of further study.
(On a relatively superficial note, the current writer - MJC – would infer tentatively that observable and superficial scores such as those obtained by the use of an IQ measure or a measure of vocabulary knowledge can only be seen as fairly gross and not-very-accurate indicators of likely capacity to cope in real settings where adequate communication and interaction involve a complexity of input and a significant demand upon processing capacity.
One might also suggest that the label of “ASD” even supplemented by the sub-label of “ high functioning ” can only be an initial indicator of likely skills and impairments, and that actual performance needs to be assessed by ongoing observations in a range of settings involving a range of tasks.)
As a preface to the study by Billstedt et al (2005), it is noted that the young people with autism who were followed up for anything up to 22 years were diagnosed in the 1980s when there was less reference to autistic spectrum disorder and the level of need might be skewed towards the more impaired levels of functioning.
The sample was augmented by a further group of young people diagnosed with atypical autism or autistic-like conditions so that the research team felt able to claim that the resulting total of 120 individuals was reasonably representative of all children with autistic or autistic-like disorders (but they add the caveat about “ as conceptualised in the 1980s ”).
They begin their report by citing existing follow-up studies completed some years ago which indicated that the intermediate-term outcomes appeared variable, but psychosocially poor on average.
Few of the young people could be regarded as independent in their early adulthood; females appeared to do more poorly than males; and more negative outcomes were observed among the group with classic autism than among the group with autistic-like conditions.
More recent studies of short term outcomes, such as that of Howlin (1998), have suggested better prognoses for many cases, perhaps reflecting earlier and more efficient interventions, the inclusion of more high functioning individuals, or some other factor(s).
However, the authors feel that little is known about the long-tem natural outcomes of autism, and their own work is presented as the first to offer a long-term perspective, based upon the hypotheses that autism would have a psychosocially poor outcome with around two thirds of cases showing no independence in early adult life, that epilepsy would be a common concomitant and the outcomes of the joint condition would be very poor, that females would be more at risk than males, and that individuals showing the core condition of autism would have significantly worse outcomes than individuals showing autistic-like conditions.
Their classification system was as follows ….
Of their sample, 57% had a very poor outcome, with no statistically significant differences across the subgroups (autistic disorder or atypical autism); 21% had poor outcome; 13% had restricted but acceptable outcome; 8% had fair outcome; and 0% had good outcome.
(Acknowledging the relatively small number of females in the study, it was reported that there was no significant association between gender and overall outcome.)
The authors summarised the findings by accepting that none of their hypotheses was clearly supported.
Poor or very poor outcomes were identified among more cases than had been predicted, and epilepsy was even more common than they had anticipated but did not predict deterioration or poor outcome to any marked degree. Female gender was not associated with worse outcomes, and the outcomes of classic autism and of atypical autism were equally restricted.
In line with other study findings, IQ at the time of original diagnosis was a clear predictor of outcomes (and it was accepted that the present findings may well have been a reflection of the low IQ rather than of autism itself) …. but outcomes were still relatively poor even for those with the higher IQ scores. None of the 120 cases had a good outcome despite the fact that around 10% had normal IQs.
Those with fair or restricted but acceptable outcomes had adequate IQs .
Further, the presence of higher level speech, including whole communicative phrases at age 6, was also linked to relatively better outcomes.
Just under 20% of the whole sample showed a deterioration during adolescence which, in around half of the cases concerned, was permanent.
Catatonia was quite commonly observed during or after adolescence … affecting around 12% of cases.
Self injury and violent behaviour were very common and a cause for much concern; and these issues plus epilepsy were held to be the most likely reasons why medication was at least considered or actually implemented.
Around half of the whole sample had a medical condition needing regular attention.
The authors concluded with a further note that their sample was not necessarily representative of all individuals currently diagnosed with autism or autistic-like conditions so that the outcomes are not likely to be typical of all cases either, and should not be generalised across all cases or used as a basis for discussing outcomes.
(However, one might infer from this study that the range of outcomes will be wide so that the label per se will not be very meaningful. An ipsative assessment and ongoing monitoring remain necessary, especially with the currently greater awareness of ASD and the growing availability of interventionist strategies plus expertise.
Further, one might also accept the reminder from such studies that ASD is a continuing problem into adulthood and that certain anomalies or differences will always be observable to a greater or lesser extent, with implications for ongoing support and understanding.)
The review article by Griffin et al (2006) is useful in highlighting the particular issues that will place a pupil with Asperger Syndrome at a disadvantage in the classroom …. namely, the problems in making and maintaining friendships; difficulty in recognising nonverbal social cues; narrow areas of interests; poor motor skills; inflexibility; and inability to mind-read (see another person’s perspective).
While these characteristics will not be amenable to significant change, it is possible to modify the classroom environment to produce benefits for the Asperger pupils.
Such modifications, as set out by Kaufman (2002), would include a highly consistent and structured routine for the school day; systematic social skill advice and communication practice/rehearsal; social mentoring; and modified instructions and demands.
In particular, the risk of teasing needs to be averted, perhaps largely via raising peer understanding of the nature of ASD and creating cooperative working groups (with each member given a specific role ?); or using a peer buddy and ensuring some useful activities for the long lunch time period.
Predictability of events is a key issue along with helping the individual to express his or her feelings and to contribute to a true 2-way conversation involving listening and turn-taking.
The social skills that would most usefully be highlighted and reinforced include maintaining eye contact, being aware of personal space, empathy, giving and receiving praise, understanding body language, learning how to start and end a conversation, and developing confidence in “community” participation such as learning how to use public transport.
It is noted that the children and young people in question can be subject to anxiety and even depression, with the implication for seeking to recognise and anticipate (avert) likely sources of stress, or providing visual reminders of day by day routines and early warning of impending shifts in routine, or using social stories as a means of managing some specific and idiosyncratic source of anxiety.
The use of language may also be critical in that ASD may be associated with a certain literalness or a weakness in managing abstractions, hence the need to check that instructions have been understood and that no reliance is placed upon the use of incidental learning (ie developing ideas or understanding by listening to general interchange around the class).
There may also be a need to split tasks into component parts, and allow more time for completion (perhaps with access to word processing to reduce the perceived chore of recording), plus a monitoring of performance to keep the pupils on task and frequent giving of positive feedback.
The overall conclusion from these authors echoes the common theme that Asperger Syndrome (or ASD) does cover a wide range of difficulties and styles such that it is necessary to assess any given individual, and plan accordingly, in terms of the particular profile of strengths and weaknesses whether social, behavioural, scholastic, motor, or sensory.
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Billstedt E., Gillberg C., and Gillberg C. 2005 Autism after adolescence. Journal of Autism and Developmental Disorders 35(3) 351-360
Erickson C., Stigler K., Corkins M., Posey D., Fitzgerald J., and McDougle C. 2005
Gastrointestinal factors in autistic disorder : a critical review. Journal of Autism and Developmental Disorders. 35(6) 713-727
Griffin H., Griffin L., Fitch C., Albera V., and Gingras H. 2006 Educational interventions for individuals with Asperger Syndrome. Intervention in School and Clinic 41(3) 150-155
Howlin P. 1998 Practitioner review : psychological and educational treatments for autism. Journal of Child Psychology and Psychiatry 39 307-322
Kaufman C. 2002 Asperger Syndrome : implications for educators. The Brown University Child and Adolescent Behaviour Newsletter 18 1-4
Kuddo T. and Nelson K. 2003 How common are gastrointestinal disorders in children with autism ? Current Opinion in Pediatrics 15 339-343
Landa R. and Goldberg M. 2005 Language, social, and executive functions in high functioning autism. Journal of Autism and Developmental Disorders 35(5) 557-572
© Mike Connor 2006.
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