Autism and ethnic minorities: possible referral bias?

A review of: Begeer, S., Bouk, S.E., Boussaid, W., Terwogt, M.M., Koot, H.M. (2008). Underdiagnosis and Referral Bias of Autism in Ethnic Minorities. Journal of Autism and Developmental Disorders DOI: 10.1007/s10803-008-0611-5


The issue of under- or over-representation of a disorder within specific ethnic groups is a complicated one. There are specific disorders that are under-represented within a specific ethnic group because of some protective factor that makes such group less likely to acquire the disorder. For example, the rates of skin cancer in the African-American population are significantly lower than in the European-American population(although this has led to increase mortality rates among African Americans due to reduced screenings leading to late diagnosis). Yet, it is possible that some disorders are under-represented within an ethnic group simply because a systemic clinical bias in diagnosis and referrals. To examine this hypothesis, the authors of this study first examined 712 case records of children referred for ASD assessment in the Netherlands. They found that ethnic minority children (Turkish and Moroccan)were under-represented in this sample of referred kids as compared to Dutch children (2.1% vs. 4.4%). But does this represent a bias or is it simply that Turkish and Moroccan children are less likely to have ASD due to some protective factor? To answer this question, the authors sent 6 clinical vignettes to 82 pediatricians. The vignettes varied in their descriptions of various autism symptoms. Three ethnic background were represented, including 1) European minority (French or English) 2) Non-European minority (Moroccan and Turkish) and 3) Majority (Dutch). However, the ethnicity was independent of the clinical vignette, so that the vignette sent to one pediatrician could describe a Dutch child, while the SAME vignette sent to another pediatrician could describe a Turkish child. The authors found that vignettes describing Dutch (majority) children elicited significantly more references to autism than did vignettes describing European minority or non-European minority children. However, the mean rate of ASD based on an objective scale was equal across all three groups. This suggests that objective assessments may help minimize any potential clinical biases.

Sleep problems in children with autism.

A review of: GOODLIN-JONES, B., TANG, K., LIU, J., ANDERS, T. (2008). Sleep Patterns in Preschool-Age Children With Autism, Developmental Delay, and Typical Development. . Journal of the American Academy of Child & Adolescent Psychiatry, 47(8), 932-940.

Parents of children with autism usually report that their children experience significant sleep problems, such as difficulty falling asleep. Yet, little research has been conducted on the specific type of sleep difficulties prevalent among children with autism. The authors of this paper first discussed the need to understand the nature of the sleep problems within this population. Research on sleep difficulties among children with other developmental disabilities indicate significant variability between the different disorders. For example, children with Prader-Willi syndrome have extended nighttime sleep and daytime sleepiness, while children with Rett syndrome have difficulty staying asleep during the night and frequent daytime napping. Therefore, in order to examine the type of sleep problems experienced by children with autism the authors examined the night and daytime sleep patterns of 68 pre-school children with autism, 57 children with non-autistic developmental delays, and 69 typically developing kids.

General findings:

The mean bedtime for the entire group was 9:00pm and the children took 38 additional minutes to fall asleep. The average waking time was 7:10am. Thus, the average time in bed was 10 hours, with 9:20 hours of actual sleep.

No sex differences were noted.

Autism findings:
Children with autism slept significantly less during a 24 hours cycle than children with other developmental disabilities and typically developing kids. In regards to awakening events during the night, typically developing children had more awakenings than children with autism, but the awakenings episodes of children with autism were significantly longer. This suggests that while children with autism do not seem to have difficulty staying asleep, they do experience difficulty falling asleep after sleep interruptions.

In regards to parental reports about their children sleep patterns, parents of children with autism reported significantly more sleep difficulties than parents of typically developing kids but not significantly more than those reported by parents of children with other developmental problems. However, parents of children with autism reported significantly more personal stress than parents in the two comparison groups.

Risperdone use in children with autism may improve cognitive performance

A review of: Aman, M.G., Hollway, J.A., McDougle, C.J., Scahill, L., Tierney, E., McCracken, J.T., Arnold, L.E., Vitiello, B., Ritz, L., Gavaletz, A., Cronin, P., Swiezy, N., Wheeler, C., Koenig, K., Ghuman, J.K., Posey, D.J. (2008). Cognitive Effects of Risperidone in Children with Autism and Irritable Behavior. Journal of Child and Adolescent Psychopharmacology, 18(3), 227-236. DOI: 10.1089/cap.2007.0133

Risperdone is a neuroleptic antipsychotic drug that has been extensively used for the treatment of schizophrenia, and more recently bi-polar disorder. Risperdone also became the first FDA approved drug for treatment of schizophrenia and bi-polar disorder in children. This drug has significant anxiolytic (calming) proprieties and thus it has been used “off-label” (outside FDA recommendation) for the treatment of anxiety, panic disorder, and even depression. In 2006, the FDA finally approved the use of Risperdone in children with autism.

Because of its mild sedation effects, researchers and clinicians have proposed that this drug may have a negative impact of cognition. However, research with adults with schizophrenia, as well as research with children with disruptive behavior problems, has generally found Risperdone to have a beneficial effect on cognitive performance. In this study, the authors examined the effect of Risperdone on the cognitive abilities of children with autism with severe behavior problems.

The study used a double-blind, placebo controlled methodology. The study included 38 children with autism who were participating in a clinical trial of Risperdone. 20 participants had been randomly assigned to take Risperdone and 18 participants were taking the placebo. The trial lasted 8 weeks. The children were tested with several cognitive measures, including a cancellation task (attention task), a verbal learning task, a motor-eye coordination task, and a classroom task (skill-dependent math task). No detriment from the use of Risperdone was observed in any of the cognitive measures. Instead, significantly better performance was noted among children taking Risperdone compared to those taking placebo on tasks of attention and verbal learning. The authors concluded that Risperdone does not appear to have any short term detrimental effects on cognitive function and may instead facilitate cognitive performance on some children.

Phonological Processing in Parents of Children with Autism.

A review of: Schmidt, G., Kimel, L., Winterrowd, E., Pennington, B., Hepburn, S., Rojas, D. (2008). Impairments in phonological processing and nonverbal intellectual function in parents of children with autism. Journal of Clinical and Experimental Neuropsychology, 30(5), 557-567. DOI: 10.1080/13803390701551225

I have previously reported on studies examining the “Broader Autism Phenotype,” a repeated finding that some parents of children with autism (most often fathers) have mild autistic tendencies themselves. I recently discussed a study on social cue perception and a study on seizure disorder. In the present study, the authors wanted to explore performance on language measures among parents of children with autism when compared to parents of typically developing kids. The study included 22 parents of kids with autism (14 mothers and 8 fathers) from 17 families (some families had both parents participating while most had only one parent). The comparison group included 22 parents that were matched for sex, age, IQ, and socioeconomic status. The two groups completed a battery of neuropsychological tests including the Wechsler Abbreviated Scale of Intelligence, and measures of receptive language, expressive language, phonological processing (processing of sounds), and history of reading difficulties. The authors found that when compared to parents of typically developing kids, parents of children with autism performed worse on measures of non-verbal reasoning and phonological processing. There were no significant differences on measures of verbal intelligence, expressive language, receptive language, verbal fluency, and history of reading difficulties. The findings would appear consistent with the ‘non-verbal disability’ profile that had been proposed as a marker of Asperger’s syndrome, although several recent studies have failed to provide evidence for this profile (see this review on a study on non-verbal learning disabilities in Asperger's syndrome). However, it was surprising to see any differences at all between the groups, in light of their very high intellectual functioning profile. That is, these parents were significantly above the norm in intellectual capacity, with IQ scores of 116 for the parents of children with autism and 120 for parents if typically developing children. Thus, in regards to non-verbal reasoning and phonological processing, we are not talking about “impairment” among parents of kids with autism, but instead slightly worse (but still above average) performance than parents of typically developing kids.

Infant asymmetry in children with Austim

A review of: ESPOSITO, G., VENUTI, P., MAESTRO, S., MURATORI, F. (2008). An exploration of symmetry in early autism spectrum disorders: Analysis of lying. Brain and Development DOI: 10.1016/j.braindev.2008.04.005

Many clinicians who conduct diagnostic assessments of children with suspected autism would tell you that there is something unique, yet difficult to describe, about how children with autism move. Parents often report also noticing something unique in their children's movement, and that they've noticed these patterns since the time their children were babies. Consistent with these clinical observations, some researchers have examined the movement patterns of infants who would eventually be diagnosed with autism. In this article, a team from the University of Trento (Italy) and the Univeristy of Pisa (Italy), reported on a study looking at symmetry patterns in posture among infants participating in a longitudinal study of autism. The study include 18 children diagnosed with Autism via ADOS and ADI, 12 children with a diagnosis of non-autism developmental delays, and 18 typically developing children. The parents of these children were asked to provide video tapes of their children when they were infants. Sections of the videos showing the babies awake and lying in supine position were coded for ‘symmetry’ by trained researchers who were blind to the eventual clinical diagnosis of the child. Symmetry was determined by matching the position of the baby to a standard list of infant asymmetric positions called the Positional Pattern for Symmetry During Lying. The results were consistent with the common clinical observations. Children with autism were rated as infants to be significantly less symmetric than children with developmental delays and typically developing children. Moreover, there were no differences between the typically developing children and those with non-autism developmental delays. The authors found that all of the children with low levels of symmetry were in the autism group, but that these represented only a subgroup of children with autism. This was interpreted as evidence for a possible subgroup of autism that is related to dysregulation in neural pathways associated with balance and motor movements.

Early Intensive Behavioral Intervention for children with Autism and IQ

A review of: Reichow, B., Wolery, M. (2008). Comprehensive Synthesis of Early Intensive Behavioral Interventions for Young Children with Autism Based on the UCLA Young Autism Project Model. Journal of Autism and Developmental Disorders DOI: 10.1007/s10803-008-0596-0

The Early Intensive Behavioral Intervention (EIBI) program for children with autism was created in the early 80s at UCLA. This program has been the subject of extensive research for almost 30 years and is now viewed as one of the few empirically supported treatment intervention for autism. In this article, the authors conducted an extensive review and meta-analysis of the effectiveness of this program. A meta-analysis is a methodological and statistical process that attempts to equate and compare the results of multiple past studies in order to reach a conclusion. This analysis included 14 research reports that met specific inclusion criteria. The meta-analysis was focused on examining the effect of EIBI on performance on IQ tests.

The overall effect size across studies was 0.69, which was statistically significantly different from 0 (p=0.001). An effect size of .69 is considered moderate-to-large, which suggested that EIBI is an effective intervention in leading to an improvement on performance on standardized intellectual assessment tests. The authors analyzed several factors that could have affected these results such as the duration of the treatment used in each study, the age of the child, the pre-treatment IQ level of the child, etc. Surprisingly, the training model used by the clinician was the only variable that affected the results. Those clinicians trained according to the UCLA model were more effective than clinicians exposed to other training methods.

In conclusion, the meta-analysis suggests that the EIBI is an effective treatment program leading to an improvement in intellectual functioning scores. Whether this is due to a true improvement in IQ or an improvement in the social behaviors necessary for successful completion of standardized intellectual assessment tools is up for debate. IQ scores are obtained through the use of imperfect assessment tools and therefore such scores reflect a myriad of factors such as true intellectual capacity, motivation, attention, social desirability, anxiety, etc. Yet, changes on IQ scores are highly informative because they often reflect the person’s ability to navigate the social, intellectual, and functional demands encountered in today’s educational and occupational settings.

The possible future role of antibiotics as treatment of Type 1 Autism?

An article was just released pre-publication on the Journal of Autism and Developmental Disorders. It’s not a report of an empirical study. Instead, it’s a letter to the editor of the journal written by Dr. Hari Manev and Dr. Radmila Manev from the University of Illinois. I never discuss letters to the editor on this blog, but this particular letter caught my attention. In this letter the authors present an interesting speculative suggestion of the possible role of some types of antibiotics in treating a specific type of autism. This is the basic argument:
- A number of studies have identified a mutation in the neurexin gene CNTNAP2. Not all cases of autism are related to this mutation, thus the label of Type 1 Autism was proposed by Dr. Stephan on the article “Unraveling Autism” published on the American Journal of Human Genetics (2008). Type 1 Autism would then refer to cases of autism that also have the gene mutation.
- This mutation results in a premature stop codon resulting in a non-functional CNTNAP2 protein. A stop codon is a genetic sequence that signals the end of the process of creating a protein.
- Some antibiotics, such as gentamicin and PTC124, have been shown to suppress the premature stop condons, thus preventing the specific protein deficits associated with such premature codons.
- It is theoretically possible that such antibiotics may suppress the actions of the premature codon in children with this type of autism, possibly leading to a normalization of the levels of protein related to CNTNAP2.

But would this lead to improved symptoms among children already with a full diagnosis? Or will the treatment only be effective before the CNTNAP2 mutation affects protein synthesis during early development, which would argue for early genetic testing? And of course, this assumes that indeed the CNTNAP2 mutation has a causative role in autism and is not simply a comorbid condition. We should note that none of these medications have been approved or studied as a possible treatment for “type 1” autism. Yet, the basic theoretical foundation is there to guide future research to examine the possible role of antibiotics in treating Type 1 autism.

Executive Functioning in High Functioning Autism

A review of: GILBERT, S., BIRD, G., BRINDLEY, R., FRITH, C., BURGESS, P. (2008). Atypical recruitment of medial prefrontal cortex in autism spectrum disorders: An fMRI study of two executive function tasks. Neuropsychologia DOI: 10.1016/j.neuropsychologia.2008.03.025

Executive functioning is an umbrella term used in clinical neuropsychology and cognitive neurosciences to refer to a series of “higher-order” cognitive processes usually associated with frontal lobe functioning. These include planning, organizing, categorizing, response inhibition, monitoring, multitasking, etc. Research on executive functioning and autism has provided mixed results likely due to differences in the area of executive function measured. In this functional MRI study, the authors used a new test of executive function used to assess for stimulus dependent vs. stimulus independent thoughts. Stimulus dependent refers to cognitive processing (thinking) that is associated with, or dependent on, a specific stimulus that is presented. For example, I may ask you to press the b key when you see a blue square or the r key when you see a red square. For this task the stimulus dependent phase consisted of capital letters presented in alphabetical order. Once a letter was presented, the person had to press one key if the letter contained only straight lines (such as the letter A) and a different key if the letter contained curves (such as the letter B). In the stimulus independent task, the person was presented with one letter and ask to follow the same response pattern (one key if straight lines – another key if curves). However, the second letter presented was random and did not follow the alphabetical order, yet the person was asked to respond based on the next alphabetical letter. For example, assume the first letter was “C”, then the next letter presented was the letter “H” (random) yet the person was asked to respond to the next alphabetical letter starting from the first letter presented (C), thus the next response was based on the characteristics of the letter D, even though the person was seeing the letter H. This task therefore, requires the person to continue to “think” of the characteristics of the letters in alphabetical order, independent of the letters presented (which now are distractors).

In the study the authors examined 15 adults with high functioning autism and 18 typically developing adults that were matched for age (mean 38) and IQ (mean 119). The participants performed the task while undergoing a functional magnetic resonance imaging scan (fMRI). There was no difference in accuracy or response times between the groups. Both groups showed more activation of the lateral frontal and parietal cortex on the more difficult stimulus-independent task. However, the autism group had significantly more activation of specific areas of the medial prefrontal cortex during the easier stimulus dependent condition than the typically developing group (this was interpreted as failure to deactivate these areas). The authors argued that these results suggest an atypical brain organization in HFA with limited deactivation of the rostral prefrontal cortex during easier task compared to typically developing individuals. However, the equivalent performance (both groups did just as well on the task) suggests that the fMRI findings simply reflect different approaches to cognitive performance between the two groups.

Feeding difficulties in children with autism. Is it the autism or is he just a picky eater?

A review of: Martins, Y., Young, R.L., Robson, D.C. (2008). Feeding and Eating Behaviors in Children with Autism and Typically Developing Children. Journal of Autism and Developmental Disorders DOI: 10.1007/s10803-008-0583-5

In this study the researchers were interested in examining the rates of eating behavior problems among children with autism. Based on a parent-completed questionnaire, the researchers compared 41 children with autism spectrum disorders, 14 non-affected siblings, and 41 non-related typically developing children. These children were matched on communication, socialization, and daily living skills (based on the Vineland Adaptive Behavior Scale).

When compared to typically developing kids, children with ASD had more food avoidance behaviors (e.g. not eating something that has been touched), and food Neophobia (fear of unfamiliar foods). These ASD children were also more likely to control the feeding (feeding revolves around the child’s demands, such as timing, type of food, etc) and consequently less likely to have the parent control the feeding ('child must try the food before it is rejected', etc). Surprisingly, there were no differences in rates of ritualistic feeding behaviors, underscoring the commonly observed phenomena of ritualistic feeding behaviors among typically developing children.

However, when compared to their unaffected siblings, the ASD children continued to display higher rates of food avoidance behaviors and food Neophobia. Yet, both groups had the same level of control over feedings. This suggests that the findings concerning high levels of child control over feedings and low levels of parent control over feedings observed in the ASD group when compared to the typically developing group, could reflect parenting styles (since the parent seems to display the same behaviors towards the unaffected sibling) rather than something unique about the child with autism. It is also possible that the parenting behavior towards the unaffected sibling (such as allowing the child more control over the feeding situation) may simply be a management tool (whether conscious or not) used in order to standardize the feeding process in a household with a child with special needs (such as to not appear unfair to the unaffected sibling).

Two last comments. It is possible that the failure to see significant differences between the children with ASD and the unaffected siblings may be a pure artifact of the limitation of the statistical tools uses. The authors compared 14 matched pairs (N=14 per group) on 7 outcome variables via standard ANOVA. An argument can be made that the statistics used were not appropriate for the nature of the data due to limited power.

Finally, I initially had a concern about the fact that these groups had been matched on several functioning scales. I thought that the results would not be generalizable since the groups were purposely selected to be almost identical on many key factors. But the fact that they found significant problems with food avoidance and neophobia in the ASD group but not the others underscores how prevalent these eating behavior problems may be among children with ASD.

Children with Autism have difficulty recognizing emotions from whole body movements.

A review of: Parron, C., Da Fonseca, D., Santos, A., Moore, D.G., Monfardini, E., Deruelle, C. (2008). Recognition of biological motion in children with autistic spectrum disorders. Autism, 12(3), 261-274. DOI: 10.1177/1362361307089520

A human point-light display is created by filming a set of lights attached to the joints of a person as the person moves. The film is done in a dark room so that only the lights are visible and captured by the camera. By watching these lights as they move in space, typically developing children and adults can identify very specific information about the person, such as the gender and emotional states. In this study, the authors compared 23 children with autism spectrum disorder (7 to 18 years of age; mean IQ = 94; SD=15 Range 85-120) diagnosed based on DSM-IV criteria via ADI against 23 typically developing children matched for sex and age. The children were presented with 20 video clips of point-light displays (10 of a male actor, 10 of a female actor). Five of the clips showed the actor displaying emotional states such as happy, sad, and angry. The children were asked to identify what they see. Responses were coded for accuracy in identifying the object (person vs. other object such as a ball), the action (jumping, running, etc), subjective state (tiredness, bored), and emotional state (sad, happy). There was no statistically significant difference between the children with ASD and typically developing kids in their ability to identify the action, the subjective state, or the object. However, children with ASD displayed significantly more difficulty in identifying emotions from the point-light displays when compared to typically developing kids. This suggests that the reported difficulty in the processing of non-verbal emotional information among children with ASD may be influenced by difficulties in understanding the motional content embedded in whole body movements. Two related comments: The performance accuracy of children with ASD in identifying the action and the subjective states was also below that of typically developing kids, but these differences did not reach statistical significance. However, based on the graph included in the paper, it appears that the mean differences were large and the non-significant finding was most likely a byproduct of the small sample size used. Unfortunately the group means and standard deviations were not provided, which would allow us to test the necessary sample size needed to reach statistical significance. This relates to my second comment. The groups were not matched for IQ. The authors argued that IQ was unrelated to performance in the ASD group, but this analysis is limited by the small sample size of the ASD group, which possibly violated the assumptions of the statistical tool used to examine the effect of IQ (ANCOVA). Thus it is possible that the ‘average’ group differences observed are indicative of group differences in intellectual capacity rather than to something unique to ASD.

Autism and Childhood Disintegrative Disorder

A review of: Palomo, R., Thompson, M., Colombi, C., Cook, I., Goldring, S., Young, G.S., Ozonoff, S. (2008). A Case Study of Childhood Disintegrative Disorder Using Systematic Analysis of Family Home Movies. Journal of Autism and Developmental Disorders DOI: 10.1007/s10803-008-0579-1

I’m always hesitant to discuss or review case reports on this blog. Case reports have a very limited target audience (related researchers and clinicians) and even more limited utility. These are reports on single clinical cases, often of extremely rare conditions that are difficult to study with traditional research methods. Often, case reports include very detail information about a particular issue that is intended to stimulate questions for future research. Case reports are not intended to present generalizable data about the nature of a condition, such as the causes or efficacy of a treatment, etc. Unfortunately, case reports are often picked up by the media, which incorrectly reports the findings as scientific evidence for X or Y. Case reports, regardless of the question, population, or condition, of interest, do not provide scientific evidence for anything. They are needed, and useful, but only as they stimulate questions for future research.

In line with this position on case reports, I won’t necessary report the results of this study. Instead, I want to comment on a couple of interesting issues that the authors discussed. This case report was an examination of a child presenting with childhood disintegrative disorder (CDD). In the study, the authors examined home movies taken throughout the child’s early infancy and early childhood to validate the diagnostic description of CDD as compared to regressive autism. A major strength of this report is its use of home videos as a source of observable data about the kids’ behavior. This technique provides a great tool for both researchers and clinicians who often have to rely only on parental reports. Although home videos are not completely free of problems and biases, they do provide clinicians with added information about the child, and specially changes in the child’s behavior over time.

The authors also discussed the diagnostic overlap between childhood disintegrative disorder and childhood autism of regressive type. In this particular case report, the child showed typical development until the age of 4, which was followed by an abrupt loss of skills and functioning. After this regression, the child clinical profile was consistent with a diagnosis of autism, and he actually received a diagnosis of autism. However, upon analysis of home videos and extensive interview with the parents, the diagnosis was changed to CDD because there was no evidence of atypical development prior to the age of 4. Although in this case the differential diagnosis is clear (assuming typical development until the age of 4), when the regression occurs earlier, the differential diagnosis becomes more complex. The authors noted:

“In theDSM-IV-TR, there is a 1-year period of overlap for the timing of the regression, such that a child experiencing developmental losses between ages 2 and 3 could meet criteria for either Autistic Disorder or CDD (American Psychiatric Association 2000). Another point of potential overlap is that some reported cases of CDD present with atypical development prior to the regression (Volkmar 1992; Volkmar and Rutter 1995), just as do some children with autistic regression (Ozonoff et al. 2005)”

But why the semantic splitting? Does it really matter if the child has Autism or CDD? At the individual level, based current available treatment interventions, no. Unless, as reported in this case, access to services is more limited after a diagnosis of CDD as compared to a diagnosis of autism. Therefore, when diagnostic criteria are met for both conditions, one should consider the effect that a specific diagnosis could have on the child's ability to access needed services. But in general, the utility of this differential diagnosis may be more relevant to researchers, as it defines a possible source of heterogeneity that may inform the research on developmental trajectories, causes, and treatments for different types of autism-like childhood conditions.

Autism Regression: A prevalence study

A review of: Baird, G., Charman, T., Pickles, A., Chandler, S., Loucas, T., Meldrum, D., Carcani-Rathwell, I., Serkana, D., Simonoff, E. (2008). Regression, Developmental Trajectory and Associated Problems in Disorders in the Autism Spectrum: The SNAP Study. Journal of Autism and Developmental Disorders DOI: 10.1007/s10803-008-0571-9

Although most children with autism present very early signs and symptoms and a linear developmental trajectory, a small subset of children present a trajectory characterized by normal development followed by a loss of acquired skills or a failure to use the acquired skills. This pattern has been termed autistic regression. Possible explainations for this phenomenom have varied from a genetic effect on brain restructuring and pruning during the early stages of life, to enterocolitis due to vaccinations, to epilepsy. In this study, the authors explored differences in developmental outcomes for children with and without regressive autism, and the association between regression and enterocolitis and epilepsy. This study examined a population cohort born in the UK in 1990 and 1991. Out of 56,946 children in this cohort, 218 had and ASD diagnosis by age 10. A subset of these children were evaluated via ADOS and ADI and divided into a broad autism (N=105), narrow autism (N=53), and no autism (N=97). The narrow autism group met full criteria for autism based on ICD-10. The broad autism group met clinical consensus for autism but not full ICD-10 criteria. These children were then evaluated for history of epilepsy, gastroinstestinal problems, and developmental regression. 39% of children with narrow autism had a history of regression during development. This compared to 11% of children with broad autism, and 3% of children with no autism. On average this regression occurred around the 25 month of age. There were no differences in IQ or adaptive functioning between those with or without regression. However, those with regression classified in the broad autism group had significantly more symptoms than those without regression also classified in the broad autism group. Regression was not associated with gastroinstestinal symptoms or with epilepsy.

Acetaminophen use and Autism.

A review of: Schultz, S.T., Klonoff-Cohen, H.S., Wingard, D.L., Akshoomoff, N.A., Macera, C.A., Ming Ji, . (2008). Acetaminophen (paracetamol) use, measles-mumps-rubella vaccination, and autistic disorder: The results of a parent survey. Autism, 12(3), 293-307. DOI: 10.1177/1362361307089518

A study in the latest issue of the journal Autism examined the possible role of acetaminophen use after MMR vaccine and autism. The authors provided an excellent review of the MMR vaccine-autism research, which indicates that although some clinical studies have found a link, most epidemiological studies have failed to find an association between MMR and autism. The authors noted that acetaminophen is commonly used to treat the adverse reaction of MMR vaccinations such a fever and rash. In addition, one study (Alberti et al, 1999) showed that some low functioning children with autism process acetaminophen differently. Thus, the authors proposed a innovative hypothesis: Does acetaminophen use after MMR vaccination increase the risk for Autism?

The authors recruited parents of typically developing children and children with autism via internet advertisement. The total sample included 83 parents completing the survey for children with autism and 80 parents completing the control survey. The surveys included a variety of questions about the child such as age, gender, what medications were used to prevent or treat reactions to the MMR vaccine, including aspirin, acetaminophen, or ibuprofen. The survey of parents of children with autism included additional questions about their children diagnosis such as whether a regression in development was observed.

The authors found that parents of children with autism reported:
- more adverse effects of MMR vaccine, including fever, diarrhea, irritability
- increased presence of concurrent illnesses with MMR vaccine
- more acetaminophen use after the MMR vaccine among children who had a reaction to the vaccine, children who had a regression in development, and those under 5.
- more acetaminophen use between 12 and 18 months of age
No association was found between ibuprofen use and autism.


A few caveats:
The finding that parents of children with autism reported more adverse effects of MMR vaccine or more concurrent illnesses with MMR vaccine is not overly informative. Note that these results were based on parental reports via internet with no possibility of verification of accuracy of such reports. So it is completely plausible to argue that given the extended media coverage of the vaccine-autism link, some parents of children with autism are more attuned to their children histories after vaccination and thus are more likely to remember or report complications. What is informative and actually interesting is that there was a significant difference in reports of acetaminophen use as compared to ibuprofen use. This difference can not easily be explained on the basis of some report bias. The problem is that acetaminophen use was reported much more frequently than ibuprofen use by all parents. So it could be argued that since parents of children with autism were more likely to report complications (even if just a by-product of recall bias), the use of acetaminophen will also appear to be different between the two groups.

Perception of voice gender in high functioning autism

A review of: Groen, W.B., Orsouw, L., Zwiers, M., Swinkels, S., Gaag, R.J., Buitelaar, J.K. (2008). Gender in Voice Perception in Autism. Journal of Autism and Developmental Disorders DOI: 10.1007/s10803-008-0572-8

Social perception using non-verbal means, such as recognition of the social information embedded into facial expressions, voices, and gestures, play a key role in social communication. Unlike typically developing kids, babies that are later diagnosed with autism do not show a preference for their mother’s voice as apposed to other voice sound. The authors of this study reviewed this and other evidence of atypical sound processing in autism, specially the finding that people with high functioning autism have an atypical cortical processing of voices when compared to typically developing kids. Based on these findings, the authors wanted to explore if theses differences in sound processing result in impaired ability to recognize the gender of a speaker base solely on voice perception.

The study included 20 adolescents with high functioning autism and 20 typically developing adolescents who were matched for IQ, gender, and age. Diagnoses were based on DSM-IV criteria and confirmed via ADI. The participants were presented voice fragments via headphones and were instructed to determine whether the voice was of a male or a female. The authors used a specialized software to morph the gender of the voices and thus present fragments that slowly changed from stereotypically masculine to stereotypically feminine.

The authors did not find any group differences in the accuracy for identifying the correct gender. Typically developing kids and those with high functioning autism were as accurate when identifying the gender of voice fragments. However, significant differences were observed in the speed of responding but only for the originally male morphed voices (male to female morph).

Please note however, that the differences in response time were not simple a 'mean' difference with those with HFA responding slower than typically developing kids. Instead, typically developing kids had a linear increase in response time as the voices were morphed. For example, they responded much faster when the voice was not morphed (original male voice presented as male voice) but gradually increased their response time as the voices were morphed, so that the slowest response time was when the voice was completely morphed (original male voice presented as a female voice). However, for those with HFA the effect was not linear. They responded fast when the voice was not morphed, slowed as the voice began to get morphed, but then became fast again when the voice was completely morphed.

The authors conclude that children with high functioning autism are not impaired in the perception of voice gender, but instead use a different perceptual approach resulting in different response times.

Mercury Exposure and Autism: Should you check for nearby power plants?

...But this study is compelling in showing an association between mercury exposure and autism rates, and scientists can not just ignore it under the basis of its imperfect design and inability to make causal links – if that is the case, then only carefully controlled laboratory studies, with poor external validity, should be published and accepted as contributors to our greater scientific knowledge.

A review of: PALMER, R., BLANCHARD, S., WOOD, R. (2008). Proximity to point sources of environmental mercury release as a predictor of autism prevalence. Health & Place DOI: 10.1016/j.healthplace.2008.02.001

This fascinating, yet bound to be controversial, study hit the news yesterday as it was made available (pre-publication) by the Journal Health & Place. The study is simple, straightforward, elegant, with some powerful findings. In fact, the findings are somewhat daunting given the simplicity of the design. The researchers reviewed the amount of mercury release reported by industrial facilities and power plants in the State of Texas in 1997 from data provided by US Environmental Protection Agency Toxics Release Inventory. They compared these data against autism rates in 1997 and 2002 as measured by schools' autism classifications provided by the Texas Education Agency. Using a specialized geographical analysis system, the authors were able to locate each source of mercury and calculate the distance between each mercury source and each school. The results:

Industrial release of mercury and distance to industrial sources independently predicted increased rates of autism. The association with industrial release of mercury was not linear, instead the statistical model fit suggested an accelerated risk. This association remained statistically significant after controlling for specific variables such as SES, urbanicity, and race.

Power plant release of mercury and distance to power plant independently predicted increased rates of autism. In this case the association was linear (not accelerated). Again, this association remained statistically significant after controlling for other variables.

It is easy to dismiss these findings as inconsequential because they are ‘correlational’ in nature, or do not really prove anything. Researchers are too often guilty of selective acceptance of research: those studies that fit the consensus are accepted while those that don’t are dismissed for their methodological flaws – even though the studies we accept are equally flawed.

In the spirit of fairness I have to say that these findings are strong. Their methodology and analytical process are not any different from what is commonly seen in social science or epidemiology research. Is it perfect? Far from it. Is it useful or informative? Definitively! The data speak very clearly: In Texas, mercury release from industrial sources and power plants in 1997, and school proximity to these sources, are associated with rates of autism in 2002 as measured by school special education classifications.

Does this mean that mercury causes autism? Not at all. In the last sentence of the previous paragraph you can not replace the words are associated with with the word cause. There is a major difference. The data, albeit strong, have limitations. For example, the most obvious (to me) alternative explanation is that mercury release and proximity to these sources is also associated with another mystery factor that is causing this apparent association and that in fact, mercury release has nothing to do with autism rates in 2002. Let’s hypothesize that these power plants and industrial sources also release another toxin – let’s call this toxin autisimic (this is a made up toxin). These sources release mercury and autisimic at the same rate, so for each pound of mercury released there is a pound of autisimic released. It is possible then that this autisimic toxin directly increases the risk for autism, and this could explain completely the strong (but now obviously inaccurate) association between mercury release and autism.

Does this study show that vaccines cause autism? Absolutely not. I know this question may sound ludicrous to some, but I pose it rhetorically because I am certain that some will make the wide leap and link these findings to the vaccine issue.

There are other problems and limitations with this study, such as how autism rates were calculated (using all children instead of only those born inor after 1997), whether the autism rates are truly climbing and not explained by other factors, whether there are other variables that could be explaining this relation, etc, etc --- and yes, this study does not prove or directly indicate that autism is caused by mercury exposure (click here for a much more critical review of this study). But this study is compelling in showing an association between mercury exposure and autism rates, and scientists can not just ignore it under the basis of its imperfect design and inability to make causal links – if that is the case, then only carefully controlled laboratory studies, with poor external validity, should be published and accepted as contributors to our greater scientific knowledge. This is study is far, far, from perfect, and many changes should have been requested prior to publication, but I can say the same of 90% of what is published today.

Autism and the gender gap

Typically developing boys score higher than girls on autism scale.

A review of: Williams, J.G., Allison, C., Scott, F.J., Bolton, P.F., Baron-Cohen, S., Matthews, F.E., Brayne, C. (2008). The Childhood Autism Spectrum Test (CAST): Sex Differences. Journal of Autism and Developmental Disorders DOI: 10.1007/s10803-008-0558-6

This large-scale study examined gender differences in the Childhood Spectrum Test, a parental report of autism symptoms for use in primary schools. The test consists of 37 questions covering communication, social behaviors, and other symptoms of Autism Spectrum Disorder, but more specifically Asperger’s syndrome. A score of 15 or above is considered to be in the clinical range suggesting the presence of an ASD. The test was completed by 3,334 parents of typically developing kids attending elementary schools in England. There were equal number of boys and girls. The results were compelling. Boys had a statistically higher median score than girls (5 vs. 4, p < .001). But most notable, 103 kids (3%) had scores in the borderline range (12-14). This group was composed of 75 boys (73%) and 28 girls (27%). In addition, 102 kids (3%) had scores in the clinical range (>14). As you may expect, 79% (81) of these were boys.

Is the gender gap observed in the parental responses to this particular scale a reflection of true gender differences in the rate of ASDs – as predicted by the Extreme Male theory of Autism? Or do these results tell us more about a possible fundamental bias in our view of expected behaviors as they relate to ASDs? That is, gender differences may exist in communication styles, play preferences, and social behaviors, which are often view as ‘soft’ signs of autism spectrum disorders. Unfortunately this particular study will not give us the answer, for the results are consistent with both theories. It is also possible that both positions are not unique, or orthogonal, since the gender differences in communication styles, etc, may result from the underlying mechanisms proposed by the Extreme Male theory: a male tendency for systematizing and an impairment in empathizing.

A micro history of the recent mercury autism controversy.

A commentary on: Aschner, M. (2008). Response to Article by DeSoto and Hitlan on the Rlationship Between Mercury Exposure and Autism. Journal of Child Neurology, 23(4), 463-463. DOI: