Elevated zonulin levels in ADHD = more hyperactivity and "impairment of social functioning"

"Children with ADHD [attention-deficit hyperactivity disorder] had higher serum zonulin levels and were more impaired in social functioning compared to controls."

So said the findings reported by Gonca Özyurt and colleagues [1] exploring a topic quite close to my research heart, zonulin and the assumption that "the level of zonulin increases when intestinal permeability is impaired."

Before heading further into the Özyurt findings, I'll perhaps refer you to some of my previous musings on the topic of zonulin (see here) and the hows-and-whys of this potentially important compound. It's rooted in the idea that intestinal permeability is perhaps rather more than it should be in some people with some labels (see here) and this *could* have some important implications for biochemistry and beyond; particularly the notion of a 'gut-brain' relationship (see here).

Özyurt et al examined zonulin in the context of attention deficit hyperactivity disorder (ADHD) based on the idea that: "Zonulin has been shown to be associated with social impairment in children with autism spectrum disorder" but such functions (and other attention-related behaviours) have not yet been looked at with ADHD in mind. Based on the examination of serum zonulin levels in some 40 kids diagnosed with ADHD and a similar number of not-ADHD controls, analysed via "enzyme-linked immunosorbent assay", researchers reported that: "Children with ADHD had higher serum zonulin levels and were more impaired in social functioning compared to controls." Also: "The level of zonulin was independently predicted with hyperactivity symptoms and SRS [Social Responsiveness Scale] scores in regression analysis."

Bearing in mind that the Özyurt study was a fairly small scale study that utilised a methodology that has its critics (see here), I'm cautiously interested in the presented findings. I don't want to say anything further about this at the present time; aside that is, from the need for quite a bit more data on this potentially interesting relationship...

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[1] Özyurt G. et al. Increased zonulin is associated with hyperactivity and social dysfunctions in children with attention deficit hyperactivity disorder. Compr Psychiatry. 2018 Oct 29;87:138-142.

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Autistic traits assessed between 5 and 8 years old are 'primarily stable'

The findings reported by Hideyuki Haraguchi and colleagues [1] (open-access available here) provide the [brief] blogging fodder today and their conclusion that: "total and two subdomain-related autistic trait scores remained primarily stable in males and females" in the general population. Further that "assessing autistic traits before school entrance may aid in predicting later autistic traits as well as other co-occurring social and emotional problems."

Autistic traits were measured "by a mother-reported quantitative measure, the Social Responsiveness Scale, at age 5 and 8 years." The Social Responsiveness Scale or SRS has some good history with autism in mind both from a research and clinical perspective. In this case the Japanese version of the SRS was used, and data from total scores and "Social Communication and Interaction (SCI)" and "restricted and repetitive behaviors (RRBs)" domains also reported on in approaching 170 "Japanese community-based children."

Results: "We found that although autistic traits assessed by the SRS decreased slightly from age 5 to 8, the extent of this change did not reach statistical significance in this sample, indicating that autistic traits are primarily stable during this transition period at the group level."

This is an important finding. Whilst one has to be careful of any sweeping generalisations that for example, the expression of autistic traits by individual children or smaller subgroups might not be as stable as you think (see here and see here), the results do have implications for various areas. Not least those areas connected to the idea that autistic traits might have some subsequent important 'influence' on later psychopathology (or indeed, a subsequent diagnosis of autism). I say this in several important contexts covering the presence of depression and anxiety (see here) and also in relation to other 'overlapping' spectrums (see here and see here) and what this *could* mean for some potentially life-threatening risks (see here and see here).

The next stage of such research? Look beyond the late childhood years and into adulthood with autistic traits in mind.


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[1] Haraguchi H. et al. Stability of Autistic Traits from 5 to 8 Years of Age Among Children in the General Population. J Autism Dev Disord. 2018 Oct 5.

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Results "provides support for the possibility that some children with ASD may benefit from IVIG": but do they?

I had high hopes for the paper by Kathleen Connery and colleagues [1] titled: "Intravenous immunoglobulin for the treatment of autoimmune encephalopathy in children with autism." It talked about screening for various "brain-targeted autoantibodies" under the label of autoimmune encephalopathy (AIE) and the use of intravenous immunoglobulin (IVIG) as an intervention, all in the context of autism. Important and timely issues.

Unfortunately, after having read the paper a few times, high hopes dissipated somewhat in terms of some of the methodology employed and the 'support' provided by some of the test results obtained for using something like IVIG...

AIE covers quite a bit of diagnostic ground. First and foremost, it represents a disease where a person's own immune system starts to recognise 'self' as 'other' and starts attacking healthy brain cells, leading to inflammation of the brain. AIE is a serious condition that in some cases leads to death. Other symptom manifestations include seizures accompanied by various cognitive, behavioural and psychiatric consequences. In short, it is not something that anyone would want. It also requires prompt identification and treatment. If you need a good example of this, type in the words 'brain on fire' into your search engine and read on...

I've talked quite a bit on this blog about encephalitis (brain inflammation) in the context of autism (see here and see here for examples). Indeed, some big names in autism research are coming around the idea that brain inflammation in the context of some autism is a very real concept (see here). Although correlation does not necessarily equal causation, the coincidence of autistic signs and symptoms appearing alongside cases of encephalitis is hard to ignore. Particularly when some authors have talked about an 'autistic regression' [2] in the context for example, of N‐methyl‐d‐aspartate receptor antibodies (NMDAR‐Ab) encephalitis. In the same breath, some of those peer-reviewed documented cases of encephalitis and autism co-occurring have also talked about treatment. And in some cases, the treatment of choice was immunotherapy including IVIG.

So, back to the Connery paper. Some 80 children diagnosed with an autism spectrum disorder (ASD) were included for study. They were all evaluated at a "multispecialty clinic for AIE." They were (variably) screened for various autoantibody markers "by several panels." This included "antineuronal nuclear, anti-glial nuclear, Purkinje cytoplasmic, P/Q and N-type calcium, and VGKC antibodies as well as GAD65, AMPA, NMDA, and GABA-B receptor antibodies" headed under the term 'Paraneoplastic panel'. Something called the 'Cunningham panel' was also undertaken: "antidopamine D1 receptor (D1R), antidopamine D2L receptor (D2R), anti-lysoganglioside GM1, anti-tubulin, CaMKII." I believe that one of the authors on the Connery paper was also an inventor of this Cunningham panel. I should also reiterate that participants were 'variably' screened using the different panels. What this means is that not every child received the total panel of screening available

Results: perhaps most importantly we are told that within this cohort: "very few demonstrated autoantibodies usually associated with AIE in children." Having already focused in on NMDA receptor encephalitis, researchers observed that none of their cohort (who were tested) showed a positive result for NMDA receptor autoantibodies: "NMDA receptor autoantibodies were negative in all of the 34 patients in which it was tested."

Further: Using pre-defined criteria for being positive, "the Cunningham panel was positive in 44 (57%) of the 77 patients in which it was performed." I don't know too much about the Cunningham panel outside of what the company who offer it say about it on their website. I did happen upon one study [2] which looked at its use for potentially diagnosing Pediatric Acute Neuropsychiatric Syndrome (PANS) and concluded that 'must do better' was the best opinion to be given; also observing that "pathological Cunningham Panel results were present in 18 of 21 healthy controls." To provide some balance, there was some further correspondence linked to the Hesselmark/Bejerot paper (see here) regarding incorrect methodology being used. But even after this, the authors still concluded that: "Our results indicate that the [Cunningham] panel does not contribute to correct diagnosis in a clinical setting."

No mind, IVIG was eventually recommended for 49 participants (60% of the cohort). Those autoantibody panels were not however, the only route to receiving an IVIG recommendation, as authors also mention that "patients with severe behavioral or medical symptoms including drug-resistance epilepsy and/or immunodeficiency were considered candidates for IVIG treatment." In all, results are reported for 31 children who received IVIG under the watchful eye of the authors' care team.

So what happened when IVIG was given? Well, this is perhaps also where the Connery paper has perhaps over-stretched itself in terms of what results are presented. Various cognitive and behavioural outcomes are reported on as a function of 'before' and 'after' use of IVIG. The authors for example, talk about use of the SRS - "for measuring the social aspects of ASD" - and observed evidence of statistically significant differences. But one needs to bear in mind that this was not a blinded trial and therefore to say that any gains were present as a direct result of IVIG treatment is pushing it a little. I'm also left slightly unimpressed with the idea of 'best responders' on the basis of such immunological and behavioural results too on the basis of this study alone. At least however, the authors don't shy away from the quite frequently reported adverse effects *correlating* with IVIG use: "Sixty-five percent (20/31) of patients reported adverse effects, most commonly headaches and vomiting" and the need for caution when considering IVIG in the context of some autism.

As I said, I did initially have high hopes for the Connery results and indeed, there are some important research directions they raise which need appropriate follow-up. One of them is the possibility that PANS *might* be something not uncommon to the autism spectrum (see here). I did however come away less than impressed with elements of the design of their study and some of their interpretations of their findings. I don't want to poo-poo the idea that some manifestations of autism might be linked to the presence of AIE or that IVIG might be an intervention option for some. Unfortunately however, the Connery paper does not really provide the ideal evidence for either concept, which is a pity...

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[1] Connery K. et al. Intravenous immunoglobulin for the treatment of autoimmune encephalopathy in children with autism. Transl Psychiatry. 2018 Aug 10;8(1):148.

[2] Hesselmark E. & Bejerot S. Biomarkers for diagnosis of Pediatric Acute Neuropsychiatric Syndrome (PANS) - Sensitivity and specificity of the Cunningham Panel. J Neuroimmunol. 2017 Nov 15;312:31-37.

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Sulforaphane and autism continued: metabolomics wades in...

"We identified 77 urinary metabolites that were correlated with changes in symptoms, and they clustered into pathways of oxidative stress, amino acid/gut microbiome, neurotransmitters, hormones, and sphingomyelin metabolism."

So said the findings reported by Stephen Bent and colleagues [1] continuing a theme in autism research circles examining the use of a compound called sulforaphane - "a supplement with indirect antioxidant effects that are derived from broccoli sprouts and seeds" - in the context of [some] autism (see here). Once again, I'm sure that there may be people out there with brows furrowing when it comes to talk of a 'broccoli chemical' potentially impacting on the presentation of autism. But peer-reviewed science (placebo-controlled) is peer-reviewed science [2] and not just to be 'put to one side' because it doesn't follow the trends or [research] fashions of the day.

This latest work from Bent et al represents a not-so-methodologically strong attempt (i.e. not placebo-controlled) to bring the science of metabolomics into research proceedings to "examine changes in physiological markers that may underlie beneficial treatment effects from sulforaphane by analyzing changes in urinary metabolites." Metabolomics by the way, as well as being music to my research ears, is something that percolates through quite a lot of autism research these days (see here and see here for examples) as small molecules in urine, blood and other biofluids are separated, detected and elucidated all in the name of science.

A small group of children participated in the Bent study; all had a "formal diagnosis of autism", all were reasonably happy to swallow a tablet containing sulforaphane ("weight-based dosing of sulforaphane") and all were able to provide urine samples before the study started and at the conclusion of the 12 week research period. Parents of participants were also willing and able to complete a couple of behavioural schedules: "the Aberrant Behavior Checklist (ABC) and... the Social Responsiveness Scale (SRS)" at "baseline, 4 weeks, and 12 weeks using an online and secure platform" about their children too.

Results: alongside looking at pre- and post-intervention behavioural scores, the authors also "examined the number of participants who had a clinical response." This is a particularly important detail in the context of autism and the continuing discussions about how the spectrum is well and truly heterogeneous (the autisms?) and so one shouldn't expect every single person diagnosed to somehow have the same genetics and/or biochemistry; also affecting response to any particular intervention. With that in mind, authors also reported that (group) scores on one of their primary outcome measures - the SRS - were significant, indicative of some positive change noted to behaviour over the course of the intervention period. I say this bearing in mind that this was an open-trial, where everyone took sulforaphane and everyone knew that they were taking sulforaphane (including the parents who did the scoring). As for those potential 'best-responders' to sulforaphane use, we are told that: "Eight participants had a clinical response compared to seven who were classified as non-responders."

Then to those metabolomic results, and from a total of nearly 700 compounds identified in urine, approaching 80 of them seemed to show some correlation with the behavioural symptom changes noted. They were put into various categories depending on their biochemical form and/or action, and correlations with behavioural scores (and significance) were presented. Some of the best correlations that I could see were with regards to sphingomyelin metabolism. The authors did seem a bit surprised by results in this area, but added: "It is not clear how sulforaphane might alter sphingomyelin metabolism or availability and whether this is related to clinical benefits, but if this association is confirmed, it has important clinical and treatment implications." I daresay that examination of sphingomyelin metabolism in other contexts (see here for example) might be revealing, particularly in the context of other behavioural/psychiatric labels [3] that could (and do) overlap with autism.

There is a further scheme of work to be followed when it comes to sulforaphane and autism on the basis of these and other scientific results [4]. I'd also suggest that the continued incorporation of the science of metabolomics is a good thing, and adds a further tier of investigation when it comes to studying intervention more generally in the context of autism. It's also an important step in (eventually) coming up with a 'test' for who might be a best-responder to the use of sulforaphane and perhaps associated compounds...

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[1] Bent S. et al. Identification of urinary metabolites that correlate with clinical improvements in children with autism treated with sulforaphane from broccoli. Molecular Autism. 2018; 9: 35.

[2] Singh K. et al. Sulforaphane treatment of autism spectrum disorder (ASD). Proc Natl Acad Sci U S A. 2014 Oct 28;111(43):15550-5.

[3] Castillo RI. et al. From Molecules to the Clinic: Linking Schizophrenia and Metabolic Syndrome through Sphingolipids Metabolism. Frontiers in Neuroscience. 2016;10:488.

[4] Sedlak TW. et al. Sulforaphane Augments Glutathione and Influences Brain Metabolites in Human Subjects: A Clinical Pilot Study. Mol Neuropsychiatry. 2018 May;3(4):214-222.

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"children with both ASD and subclinical autistic traits have lower neuropsychological performance"

The quote heading this post - "children with both ASD [autism spectrum disorder] and subclinical autistic traits have lower neuropsychological performance" - comes from the findings reported by Fjola Hyseni and colleagues [1].

Researchers report results from a study "embedded in the Generation R Study" (an initiative that has appeared before on this blog) examining whether neuropsychological performance as measured by "using subtests of the NEPSY-II-NL" showed any connection to autistic signs and symptoms. The sorts of things looked at via the NEPSY-II included "attention and executive functioning, memory and learning, sensorimotor, language, and the visuospatial domain."

Actually, the Hyseni study was a multi-factorial study in that their analysis "involved an ASD case versus control analysis comparing children with a diagnosis of ASD to children without an ASD diagnosis" and also "to test for a linear relationship between autistic traits and NEPSY-II performance in the entire sample." Finally, they "excluded both children with a diagnosis of ASD and children with high autistic symptoms" but still looked at scores on the Social Responsiveness Scale (SRS) as a function of NEPSY-II test performance.

Results: based on the inclusion of data from over 1000 children, there were some important details attached to the authors observation that autistic traits were negatively correlated with neuropsychological performance. So, as well as higher levels of autistic traits or a diagnosis of autism being associated with lower neuropsychological performance across various domains and taking into account various other potential confounding variables - covariates - (gender, age, ethnicity, child attention problems, etc), so those analyses of SRS scores of participants without a diagnosis of autism or high autistic traits yielded important findings. For the 960 children who this covered, authors reported that "the significant relationship between SRS scores and neuropsychological performance remained", at least when it came to memory and learning, sensorimotor functioning, and language domains following adjustment for those covariates. The authors conclude that: "Our results provide support for a relationship along the continuum between autistic symptoms and neuropsychological performance in school-age children who encompass children with subclinical autistic traits." Further investigations are implied in this area on the basis for example, that: "the measurements of autistic traits, neuropsychological functioning, and IQ were not performed at the same time; thus, there was a short time difference between the two measurements."

There are some important implications from such results. Not least, as the authors point out: "children with both ASD and subclinical autistic traits have lower neuropsychological performance" and also that they: "may provide an understanding of why some children without an ASD diagnosis may require some additional assistance within academic settings." I hasten to add that neuropsychological performance is not necessarily the same as academic performance, and so one has to be quite careful of where such discussions could lead. I also think back to those ideas that have perpetuated autism down the ages suggesting that a diagnosis of autism confers some sort of 'savant' advantage to the masses. I've talked before about how sweeping a generalisation such thinking is (see here) and indeed, the Hyseni findings kinda add further cold water to such universal sentiments. People diagnosed as on the autism spectrum are gifted in many ways, but not necessarily because of any diagnostic label they have received and not necessarily consistently so [2]...

And on the topic of autistic traits potentially 'influencing' performance, the findings reported by Crehan and colleagues [3], including one John Constantino - "the authors of the SRS" - are also pertinent. To quote: "Splitting the SRS scores into three severity classes revealed that impaired social responsiveness is significantly related to competency." One also has to wonder in the longer term, whether the sentiments expressed by Skylark & Baron-Cohen [4] on how certain autistic traits (particularly socially implicated traits) might "influence a person’s financial circumstances" could also 'interact' with the findings being discussed.

Much food for thought.

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[1] Hyseni F. et al. Autistic traits and neuropsychological performance in 6- to-10-year-old children: a population-based study. Child Neuropsychol. 2018 Apr 23:1-18.

[2] Lindor E. et al. Superior Visual Search and Crowding Abilities Are Not Characteristic of All Individuals on the Autism Spectrum. J Autism Dev Disord. 2018. May 22.

[3] Crehan ET. et al. Tracking the Influence of Autistic Traits on Competencies Among School Aged Children with Subthreshold Autistic Traits: A Longitudinal Study. Child Psychiatry Hum Dev. 2018 May 11.

[4] Skylark WJ. & Baron-Cohen S. Initial evidence that non-clinical autistic traits are associated with lower income. Mol Autism. 2017 Nov 13;8:61.

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What factors potentially predict quality of life in adults with autism?

"The study findings are that autistic people on average have lower QoL [quality of life] than the general population in the UK." Further: "Three main characteristics were predictive of lower QoL in almost all domains: being female, having a current mental health diagnosis and higher severity of autism symptoms." By contrast: "Significant positive predictors of QoL were: being employed (physical QoL), receiving support (social and environment QoL), and being in a relationship (social QoL)."

So said the findings reported by David Mason and colleagues [1] describing the results of a study that examined "quality of life (QoL) of a large sample of autistic adults in the UK and investigates characteristics that may be predictive of QoL." This is a vitally important topic because perceived quality of life IS important and has been discussed before in the peer-reviewed research arena with autism in mind (see here).

This time around the focus was on 'self-reported' quality of life for autistic adults who submitted data as part of a research initiative "into the life experiences of autistic adults, the Adult Autism Spectrum Cohort‐UK." Some 370 people (mostly) formally diagnosed with an autism spectrum disorder (ASD) completed the WHOQoL‐BREF, a quality of life assessment schedule developed by the World Health Organisation, as well as the Social Responsiveness Scale (SRS) and a initiative-specific questionnaire that collected various information including that about "everyday life including relationship status; home life including living alone or with family members (family of origin or spouse/partner); employment including paid employment, volunteering, or retired; education including type of school and qualifications achieved; support including who supports the adult and how often support is needed; mental health/neurological conditions including current diagnoses and type of medication/therapy; physical health conditions; and autism spectrum in other family members." Acquired data was put into the statistical 'measuring' machine and trends were reported.

So, a large proportion of participants were aged between 41 and 60 years old (~40%). The sex/gender ratios were fairly evenly split (males: 54% vs. females: 43% vs. 'prefer not to say' ~3%). The vast majority of respondents reported either a mental health issue as being concurrent to their autism diagnosis/status (~70%) or a physical health issue as being present (70%). I don't think we were actually told all the specific diagnostic categories that were included under 'a mental health issue' or 'a physical health issue' but some clues are provided in the text: "most commonly depression and/or anxiety" and "sleep problems, or hypertension." The WHOQoL‐BREF, by the way, provides information on QoL in various domains: physical, psychological, social and environment. Authors therefore report that: "Reported QoL for autistic adults was lower across all four domains than UK norms."

Then to those potential predictors of 'poorer' or 'better' quality of life, as some further statistical analysis was actioned on the collected data. Quite consistently - in the physical, psychological and environment domains - the same three elements cropped up as potentially predicting poorer quality of life: being female, having a comorbid mental health diagnosis and total scores on the SRS (an instrument that "measures autism characteristics" with a focus on social aspects). Looking at the statistical strength of the various factors observed, I'd have to say that the SRS score (total) - that measure of 'autism characteristics' - was the one that seemed to be most strongly related to QoL. Yes, the implications are that the [social] manifestation of autism itself *could* be an important driver of poorer QoL. Insofar as the factors potentially related to a more positive (better) quality of life, being employed, receiving support and being in a relationship were all mentioned, but certainly not as consistently across all the various WHOQoL‐BREF domains as noted in those negative predictors.

The authors highlight a few positives and negatives in relation to their study: use of a "robust measure of QoL is a strength", pretty large sample size and the collection of some good quality 'complete' results. That being said, they also note that a general QoL questionnaire might not gather all the important information relevant to QoL in the context of autism (I do wonder if all that ICF core sets of autism work might help matters on future research occasions). And then there's the issue of representativeness to consider, when it comes to the applicability of Mason results to the (very) wide autism spectrum (see here)...

Recommendations - 'implications' - aplenty spring from the Mason results. Focus in on better screening and treatment/management of mental health (and physical health) issues when concurrent to an autism diagnosis (see here and see here for examples). Make employment - long-term employment - work better for those on the autism spectrum (see here). Devote greater resources to discovering what factors surrounding female autism might lead to poorer quality of life. All noble sentiments worth pursuing. Alongside, are those results about autism severity also seemingly impacting on QoL. Does this perhaps also imply that moves to 'intervene' on core autistic symptoms might also be a target too? Y'know, on the understanding that 'core autism features' have also been *correlated* to some other, rather extreme endpoints also significantly affecting quality of life (see here)?

Addition: 10 May 2018. Y'know I mentioned that SRS scores - "measures autism characteristics" - might be an important variable when it comes to quality of life? Well, it seems another cohort came to similar conclusions [2] (click here for a larger view of figure b and those self SRS scores)...

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[1] Mason D. et al. Predictors of quality of life for autistic adults.  Autism Res. 2018. May 7.

[2] Oakley B. et al. Why Is Quality of Life Reduced in Individuals with Autism Spectrum Conditions? Investigating the Impact of Core Symptoms and Psychiatric Comorbidities on Quality of Life in the EU-AIMS LEAP Cohort. INSAR 2018.

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"results suggest that maternal CMV infections may influence ASD symptoms"

CMV infections mentioned in the title of this post - "results suggest that maternal CMV infections may influence ASD [autism spectrum disorder] symptoms" - refers to cytomegalovirus, a beta-herpes virus, that infects quite a percentage of the population, but is typically kept in check by a healthy immune system.

Although not usually a 'problem-causer', CMV infection under certain circumstances can have various unwanted adverse effects. One such circumstance is that of congenital CMV infection, where some infants acquire CMV during the nine months that makes us, and in some cases, it leads to an array of adverse physical and developmental outcomes. You probably won't be surprised to hear that congenital CMV infection has also been *linked* to some instances of autism (see here) and indeed, on more than one peer-reviewed research occasion (see here).

The findings reported by Brooke Slawinski and colleagues [1] add to this important area of autism science with their suggestion of a potentially important *correlation* between the presence of CMV infection and scores on one of the premier autism assessment tool, the Social Responsiveness Scale version 2 (SRS-2).

Authors looked for "CMV IgG and HSV2 [herpes simplex virus 2] IgG in serum from the mothers of 82 children whose ASD symptoms were assessed at 3-6 years of age using the Social Responsiveness Scale version 2 (SRS-2)." The presence of IgG antibodies typically indicates past and/or recent exposure to a pathogen (in this case, CMV) with results expressed as seropositivity or seronegativity. Authors observed that those children whose mothers were seropositive for CMV IgG antibodies scored marginally higher on the SRS than those who were seronegative for CMV IgG antibodies. They did not find a similar relationship / correlation when looking at past / recent exposure to HSV2. Ergo, children *potentially exposed* to CMV infection during pregnancy showed a more severe autism presentation than those that weren't, at least in relation to the SRS measured social aspects of autism.

Of course you can see the issues with this work as it stands. Two variables (albeit "robust to several statistical adjustments") have been brought together and a possible 'connection' made. Not for the first time I might add, where one needs to be slightly cautious about making too much of any relationship given the wide array of potentially influencing variables / confounders. There is also an inference in the Slawinski work that a positive results means that maternal CMV infection during pregnancy was present and that "prenatal exposure to maternal infections" plays a role with [some] autism in mind. That is of course, if you assume that infections post-pregnancy might not also play a role in some autism (see here for example)...

The authors sensibly announce that their findings are "being further evaluated in ongoing prospective studies with larger population samples" so there should be more to see on this topic. For now however, I think it's important to stay mindful of the fact that exposure to various infective agents - viral, bacterial and otherwise - seem very much able to influence both physiology and behaviour in a wide variety of contexts including autism. Oh, and response to infection *might* also play a role in behaviour too (see here).

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[1] Slawinski BL. et al. Maternal cytomegalovirus sero-positivity and autism symptoms in children. Am J Reprod Immunol. 2018 Mar 9.

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Maternal immune history and autism (social) symptom severity

"Pregnant mothers' asthma and allergies linked to more severe autism in their children" went one of the media headlines discussing the findings reported by Patel and colleagues [1]. Drawing on data derived from the "Western Australian Autism Biological Registry (WAABR)" researchers set out to examine whether "having an immune or autoimmune-driven MIA [maternal immune activation] is associated with increased severity of ASD [autism spectrum disorder] symptoms for the child."

The conclusions arrived at: "a positive immune history (allergies or asthma) was associated with increased severity of social symptoms in child." Said data derived from 220 families/children who were quizzed about "the medical history of the biological mother, where details regarding any diagnosed illnesses or chronic conditions were reported, along with age of any diagnosis" alongside the use of more direct measures to ascertain autistic traits in children: Autism Diagnostic Observation Schedule-Generic (ADOS-G) and the Social Responsiveness Scale (SRS).

One obviously has to be a little cautious about such results where the study was conducted 'retrospectively' and what this could mean in terms of recall [2] (although, I hasten to add, other studies of maternal recall vs. medical records in the context of autism are actually quite promising). That no objective confirmation of the presence of allergy or autoimmune disease via direct testing for example, were included in this publication is also something to be a little careful about (I'm pretty sure however, someone would know if they had received a diagnosis of coeliac disease or not for example).

So what do the results mean and what are the implications? Well, MIA - maternal immune activation - in the context of offspring autism risk is not something new (see here and see here for examples) as the authors mention in their paper. Added to work talking about how inflammation, a process that is part-and-parcel of immune function, might have the ability to 'affect' social cognitive processing (see here) one might see further evidence for how the immune system seems to be doing quite a bit more than just protecting us from the odd pathogen or two. This might be particularly relevant during pregnancy; a time when a reprogrammed immune system is in place to prevent mum's body from 'rejecting' the developing foetus and associated systems.

"Findings support the role of an immune system-mediated subtype in ASD, which may be driven by MIA and changes in levels immune markers. Identification of such a subtype in ASD will enable more streamlined diagnosis and management in clinical environments." Yes, alongside acknowledgement that there may be an 'immune phenotype' of autism (see here), the authors do mention the potential future use of "immune-modulating pharmacotherapies" in the context of the growing evidence base for MIA and risk of offspring autism. Such options are already being explored in the animal research domain as per those findings from Vuillermot and colleagues [3] and how "early dietary supplementation with vitamin D may open new avenues for a successful attenuation or even prevention of neurodevelopmental disorders following maternal inflammation during pregnancy." Vitamin D and autism is already quite a hot topic (see here for example). And things don't just stop at vitamin D neither (see here for another example) as further investigations are warranted with the hope that children with possible 'MIA autism' (if I can use that term) are "able to function and integrate into the world... [and] have a level of independence" required to do so successfully (and of course, happily).

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[1] Patel S. et al. Social impairments in autism spectrum disorder are related to maternal immune history profile. Molecular Psychiatry. 2017. Oct 10.

[2] Ozonoff S. et al. Reliability of parent recall of symptom onset and timing in autism spectrum disorder. Autism. 2017 Sep 1:1362361317710798.

[3] Vuillermot S. et al. Vitamin D treatment during pregnancy prevents autism-related phenotypes in a mouse model of maternal immune activation. Mol Autism. 2017 Mar 7;8:9.

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Vitamin A supplementation and autistic symptoms: hidden away but no significant effect...

I used the words 'hidden away' in the title of this post because I had a bit of a time deciphering the findings reported by Juan Liu and colleagues [1] (open-access) investigating "the role of VA [vitamin A] in the changes of gut microbiota and changes of autism functions in children with ASD [autism spectrum disorder]." Vitamin A by the way, is a fat soluble vitamin involved in various process such as immune function and vision health. There is a darker side to vitamin A however, as safe upper limits have been in place for quite a few years, particularly for pregnant women as a result of potential teratogenic effects.

Suffice to say that after 6 months of VA supplementation - "participants with an insufficient plasma retinol status (<1.05 μmol/L) received VAI [vitamin A intervention?] with a dose of 200,000 IU once orally" - the authors reported seeing no significant changes in autistic signs and symptoms as measured before and after using the Autism Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS) and Social Responsiveness Scale (SRS). They did however report changes in retinol status (a marker for vitamin A availability) coinciding with supplementation: "The plasma retinol level increased from 0.59 ± 0.19 μmol/L to 0.72 ± 0.20 μmol/L in the group of 64 after 6 months of VA supplementation" and changes in the percentages of vitamin A levels (typical, marginal deficiency, deficient) across their group. I say this however, based on their use of high performance liquid chromatography (HPLC) with photodiode-array detection for assaying for retinol; state-of-the-art about 30 years ago and now superseded by better detection technology such as mass spectrometry...

No mind, Liu et al also looked at "CD38 and acid-related orphan receptor alpha (RORA) mRNA levels" as "autism-related biochemical indicators’ changes" following supplementation. RORA - retinoic acid-related orphan receptor-alpha - has some research history discussed before on this blog (see here). Authors reported that: "After 6 months of intervention, plasma retinol, CD38 and RORA mRNA levels significantly increased" despite the seeming lack of effect on presented autistic symptoms.

Further: "Fresh stool samples were collected from participants who did not receive supplemental probiotics or prebiotics and who were not treated with antibiotics for the previous 1 month." Said poo(p) samples - pre and post-vitamin A supplementation - were analysed alongside food diaries and food frequency behaviours. Authors observed that bacterial species showed changes between the baseline and post-intervention samples; specifically settling on "significant increases in the proportion of Bacteroidetes/Bacteroidales and decreases in Bifidobacterium after the VAI, accompanying significant increases in autism biomarkers, while no significant changes were observed in autism symptoms."

What can we make of these collected findings? Well, whilst vitamin A deficiency is something to look out for among children with autism [2] (see here too) and previous research has indicated "an empirical basis for the development of a pharmacological ASD treatment strategy based on retinoids" [3] the lack of a significant behavioural effect from vitamin A supplementation in this case cannot be just glossed over. Yes, this was an open-trial - "we aimed to conduct a placebo-controlled intervention study, but all the participants showed an insufficient VA status and were thus enrolled into the VAI group" - and so has shortcomings but the findings of a lack of significant change across any and all of the autism-related behaviour schedules used is notable. The biological results are a little more interesting; particularly the bacterial findings. But again it wouldn't be difficult to say 'so what?' to such bacterial results given that no corresponding changes in autistic behaviour(s) were noted...

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[1] Liu J. et al. Effect of vitamin A supplementation on gut microbiota in children with autism spectrum disorders - a pilot study. BMC Microbiology. 2017; 17: 204.

[2] Chiu M. & Watson S. Xerophthalmia and vitamin A deficiency in an autistic child with a restricted diet. BMJ Case Rep. 2015 Oct 5;2015. pii: bcr2015209413.

[3] Riebold M. et al. All-trans retinoic acid upregulates reduced CD38 transcription in lymphoblastoid cell lines from Autism spectrum disorder. Mol Med. 2011;17(7-8):799-806.

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Differentiating between autism and ADHD the machine learning way (again)

So: "These results support the potential of creating a quick, accurate and widely accessible method for differentiating risks between ASD [autism spectrum disorder] and ADHD [attention-deficit hyperactivity disorder]."

That was a conclusion reached in the paper by Marlena Duda and colleagues [1] (open-access) building on their previous foray into this important research area (see here). Last time around [2] this research group - the Duda/Wall et al research combination - set the scene for boiling down the Social Responsiveness Scale (SRS) from 65 items to something considerably smaller when it came to distinguishing autism from ADHD. This based on the idea that autism and ADHD are not unstrange diagnostic bedfellows (see here).

This time around, researchers set out to "expand upon our prior work by including a novel crowdsourced data set of responses to our predefined top 15 SRS-derived questions from parents of children with ASD (n=248) or ADHD (n=174) to improve our model’s capability to generalize to new, ‘real-world’ data." Mention of the term 'crowdsourced' means that authors utilised various online social media platforms to "to inform the community of the study" and gather responses. Importantly, they note that "diagnoses of ASD or ADHD were provided as parent report."

Results: once again applying various machine learning algorithms to their recently captured data and "mixing these novel survey data with our initial archival sample (n=3417)" authors reported some interesting findings. Taking the two samples - the archival samples and the recent crowdsourced data  - together they reported on the creation of "a classification algorithm that can generalize well to unseen data (AUC=0.89±0.01), even when those data have more natural variablity like the kind seen in our survey sample." This was based on the use of 15 items from the SRS.

But... things were not all smooth sailing in this latest research effort. Bearing in mind the use of those 'parent reported' autism and ADHD participants in this latest study, authors noted that 'real-world' data is not necessarily the same as the very clinical data relied upon on the last research occasion. So: "In the archival sample, the responses for ADHD subjects were more uniform and on average less severe than the ADHD responses in the survey sample."

Still, these are important results albeit requiring 'continued evaluation' as further crowdsourced and other data filter through. Indeed 'adaption' to new data seems to be something that the authors are particularly keen on to "further improve the generalizability of the classifier." I continue to applaud their research in this area as a function of their efforts (see here) to make autism and/or ADHD screening quicker, easier and more cost-effective.

And on that last point. it is timely that such research continues given what is being proposed in certain parts of England when it comes to autism diagnoses (see here). Indeed, the suggestion of "restricting an autism diagnosis to only the most severe cases" as a function of some quite spectacular increasing demand - "The team is supposed to carry out 750 assessments a year. But it is getting almost double that level of demand, with about 25 referrals a week" - reiterates a need to streamline diagnostic services to make screening/diagnosis quicker, easier and more cost-effective.

For those also who have said 'so what' to the increase in cases of autism (yes, someone actually did albeit with caveats), such proposals to potentially restrict autism diagnoses, I would say, are a direct result of such a mindset to 're-think' autism. Although well meaning, if enough people talk about difference over disability for example, purse string holders in the NHS (National Health Service) were eventually bound to ask 'why diagnose?' and 'why offer services?' (services that can cost quite a lot and even for those with 'severe autism' are often not there). As other authors have eloquently argued (see here) and indeed, foretold, mixed in with the current economic situation being put forward all in the name of austerity, low-hanging NHS services fruit like autism screening/assessment were certain to be eventually targeted and the 'difference over disability' framing unfortunately provides ample ammunition for such proposals...

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[1] Duda M. et al. Crowdsourced validation of a machine-learning classification system for autism and ADHD. Transl Psychiatry. 2017 May 16;7(5):e1133.

[2] Duda M. et al. Use of machine learning for behavioral distinction of autism and ADHD. Transl Psychiatry. 2016 Feb 9;6:e732.

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Duda M, Haber N, Daniels J, & Wall DP (2017). Crowdsourced validation of a machine-learning classification system for autism and ADHD. Translational psychiatry, 7 (5) PMID: 28509905

Low muscle tone and autistic traits

"This large study showed a prospective association of infant muscle tone with autistic traits in childhood."

So said the findings reported by Fadila Serdarevic and colleagues [1] who, looking at nearly 3000 children, were able to assess early motor development and muscle tone "between ages 2 and 5 months" and later parental ratings of autistic traits in children at 6 years of age. Said autistic traits were surveyed using the "the Social Responsiveness Scale (SRS) and the Pervasive Developmental Problems (PDP) subscale of the Child Behavior Checklist." Authors concluded that there was something of a connection between low muscle tone and autistic traits: "Low muscle tone in infancy predicted autistic traits measured by SRS... and PDP" and further: "early detection of low muscle tone might be a gateway to improve early diagnosis of ASD [autism spectrum disorder]."

Just before anyone gets ahead of themselves with this data, it is worth pointing out that despite the large participant group included for study and the prospective nature of the study design, this was a study only really looking at two sets of variables across quite a long time-frame. It's not beyond the realms of possibility that other factors might influence the presentation of [parent-reported] autistic traits outside of just early measures of muscle tone or anything related...

But let's set this research in some context. Muscle tone in a broader sense had been noted to be potentially 'linked' to autism in some of the earliest texts on the topic (see here). More recent discussions on how motor skill in the context of gait for example, might be something important to at least some autism (see here) add to the relevance. One might also look to the some of the typical reasons why low muscle tone (hypotonia) may present to see whether there are areas that could inform autism research too. I note for example, mention of Ehlers-Danlos syndrome (EDS) in some of the texts and this would perhaps appeal to further investigation on any overlap between EDS (or other connective tissues disorders) and autism (see here). Serious infections such as encephalitis and meningitis have also been mentioned in the context of hypotonia, and again, might be indicated in relation to hypotonia and some autism (see here). There is also a possibility that hypotonia could (in some cases) be tied into mitochondrial disease; something else that could be relevant to at least some 'types' of autism (see here). All of these areas are worthy of further research inspection added to the idea that muscle tone might be rather more core to autism than many people might appreciate.

'And the best picture goes to'...

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[1] Serdarevic F. et al. Infant muscle tone and childhood autistic traits: A longitudinal study in the general population. Autism Res. 2017 Feb 9.

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Serdarevic F, Ghassabian A, van Batenburg-Eddes T, White T, Blanken LM, Jaddoe VW, Verhulst FC, & Tiemeier H (2017). Infant muscle tone and childhood autistic traits: A longitudinal study in the general population. Autism research : official journal of the International Society for Autism Research PMID: 28181411

"Androgens were not associated with autistic traits at 12 months of age"

EARLI - the Early Autism Risk Longitudinal Investigation study - has been mentioned on this blog before (see here) with the aim of the initiative to "examine possible environmental risk factors for autism and study whether there is any interplay between environmental factors and genetic susceptibility."

In this post I'm bringing the paper by Bo Park and colleagues [1] (open-access) to your attention and the observation(s) that umbilical cord blood levels of testosterone and other related androgens were seemingly not associated with autistic traits at 12 and 36 months of age in their cohort. Such findings represent yet another biological research blow (see here) to facets of the Extreme Male Brain (EMB) theory of autism and the suggestion that "ASD [autism spectrum disorder] is an extreme presentation of a typical male cognitive profile where the drive to “systemize” is stronger than the drive to empathize."

So, looking at cord blood samples from 137 children recruited on to EARLI - "a high autism-risk cohort following pregnant mothers with an older child diagnosed with an ASD (autistic disorder, Asperger syndrome, or pervasive developmental disorder not otherwise specified)" - researchers looked at whether measures of various androgens might correlate with scores on the Autism Observation Scales for Infants (AOSI) and Social Responsiveness Scale (SRS). Said schedules were administered at 12 months and 36 months respectively and various potentially confounding variables were taken into account when it came to looking at any associations. It's also worth pointing out that the technology of choice when it came to those measures of cord blood levels of androgens was an old favourite of this blog: liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Results: well as per the title of this post, and after adjustment for potentially confounding variables - "maternal age, gestational age, and cesarean delivery" - there wasn't a great deal to see in terms of levels of androgens and the presence of autistic traits. Indeed, the title of this post only tells half the story as testosterone was also found not to be associated with the SRS scores at 36 months too. The authors do note that: "Male infants (n=75) showed significantly higher umbilical cord testosterone levels and greater social deficits at 36 months of age" than females, but after adjustment for confounders this observation was left wanting. They also talk about some interesting observations about when a child had an older female sibling diagnosed with autism - "androgen levels and autistic traits may depend on sex of the older affected sibling" - but I'm not so sure about the strength of such findings and whether other mechanisms might also be at work. I might reiterate that autistic traits were the name of the research game in this study not a diagnosis of autism.

As mentioned, the Park findings represent another setback for the generalisability of the role of androgens (prenatal and beyond) in relation to autism and/or autistic traits. I guess that in these days of the plural 'autisms' (see here) it's perhaps not entirely unexpected that grand theories of autism seem doomed to fail when put up to scientific scrutiny. Indeed someone recently has talked about this [2]. I still however remain interested in the discussions around the EMB theory of autism, and although this and other research has not been entirely kind to the hypothesis, it is still perhaps deserving of further study in order to see who it may be most relevant to in these days of plural autisms and subgroupings...

To close, isn't this why Twitter was invented?

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[1] Park BY. et al. Umbilical cord blood androgen levels and ASD-related phenotypes at 12 and 36 months in an enriched risk cohort study. Molecular Autism. 2017; 8: 3.

[2] Müller R-A. & Amaral DG. Editorial: Time to give up on Autism Spectrum Disorder? Autism Res. 2017. Jan 27.

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Park, B., Lee, B., Burstyn, I., Tabb, L., Keelan, J., Whitehouse, A., Croen, L., Fallin, M., Hertz-Picciotto, I., Montgomery, O., & Newschaffer, C. (2017). Umbilical cord blood androgen levels and ASD-related phenotypes at 12 and 36 months in an enriched risk cohort study Molecular Autism, 8 (1) DOI: 10.1186/s13229-017-0118-z

Generation R does gestational vitamin D levels and autistic traits

"Gestational vitamin D deficiency was associated with autism-related traits in a large population-based sample. Because gestational vitamin D deficiency is readily preventable with safe, cheap and accessible supplements, this candidate risk factor warrants closer scrutiny."

So said the findings reported by Vinkhuyzen and colleagues [1] (open-access) reporting on data derived from "the Generation R Study, a population-based prospective cohort from fetal life onward, based in Rotterdam, The Netherlands." I've talked about this study initiative before on this blog (see here) but this time around its scientific eyes turned towards the possibility that vitamin D - the sunshine vitamin/hormone - might have some important connections to the presentation of some of the facets of autism or at least autistic traits. Yes, yet again, vitamin D and autism comes into view (see here)...

The Vinkhuyzen paper is open-access for all to see (and has already received some media exposure) but here are a few choice details:

• Hypothesis: explore "the association between gestational 25OHD concentrations and a widely used parent-report continuous measure of autism-related traits—the Social Responsive Scale (SRS)." Said levels of 25-hydroxyvitamin D (25OHD) (the functional unit of vitamin D assessment) were obtained from "maternal mid-gestation sera and from neonatal sera (collected from cord blood)." SRS scores relevant to offspring were provided by parents "when the children were ~6 years of age."
• Results: well, this certainly wasn't an under-powered study as data for "4229 children and their mothers were available with measures of vitamin D concentrations drawn from maternal blood at mid-gestation and/or drawn from cord blood at time of birth as well as data on the SRS, 2489 children and their mothers were available with measures of vitamin D concentrations at both time points." Approximately 16% of mothers were classed as deficient based on that mid-gestation serum sample rising to 36% when looking at cord blood samples. As I've mentioned before, issues with vitamin D generally fall into a few bandings associated with insufficiency and deficiency at the lower end of typical.
• "In all analyses, 25OHD deficiency or lower 25OHD concentrations were associated with higher (more impaired) SRS scores." This was based on the use of an "18-item abridged version of the questionnaire" that specifically looked at "behavioural features related to social cognition, social communication and autistic mannerisms." Remember, this was a study looking at autistic traits not autism diagnoses. Interestingly too, authors were also able to restrict their analysis to "offspring with European ethnicity" and reported similar results associating lower vitamin D levels and higher SRS scores. This subgroup analysis perhaps ties into other research where ethnicity has been suggested to be a factor in relation to vitamin D levels and diagnosed autism (see here).

So, there you have it. Yet more evidence linking vitamin D and autism and/or autistic traits; this on the back of my previous entry not-so-long-ago (see here) talking about supplementation as a potential means to affect presentation of at least some autism, with appropriate caveats (see here). It's getting increasingly difficult to say that there is 'no connection' between the two factors.

Strengths of the Vinkhuyzen study? Well, as I said, it was big in terms of participant numbers. I note also the authors proudly announce: "We used a gold standard assessment of 25OHD concentrations" in light of the application of "isotope dilution liquid chromatography-tandem mass spectrometry." A gold star for the authors indeed in light of some 'chaos' when it comes to the hows and whys of measuring vitamin D status. Limitations: well, as per every study that looks at the association between a small number of variables, there are potentially a million and one other factors that might also account for the results. Another gold star is due for the authors' mention of the fact that vitamin D seems to be 'associated' with various diagnostic labels outside of rickets these days (see here for example) and hence one cannot rule out that traits or diagnoses not specifically covered by the study could have exerted some effect. More so when one considers how much autistic traits might not be just autism-specific traits (see here). I might also add that subsequent work could/should also be looking at the genetics of vitamin D metabolism not just functional levels of the stuff (see here).

A final quote from the authors to close: "Just as prenatal folate supplementation has reduced the incidence of spina bifida, we speculate that prenatal vitamin D supplementation may reduce the incidence of ASD." I know such sentiments might not be welcomed by everyone, and the assumption that autistic traits are 'always a negative thing' needs some continued careful consideration. The ideas however that: (a) nutrition might impact on both psychology and physiology and (b) that where appropriate and/or where wanted, use of vitamin D supplement might impact on risk of autism or the presentation of autism, are ideas that are deserving of a lot more investigation.

And again, minus any charges of clinical or medical advice being given on this blog (they're not), here is what the UK Government (or parts of the UK) are currently saying about vitamin D and the population as a whole...

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[1] Vinkhuyzen AA. et al. Gestational vitamin D deficiency and autism-related traits: the Generation R Study. Mol Psychiatry. 2016 Nov 29.

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Vinkhuyzen AA, Eyles DW, Burne TH, Blanken LM, Kruithof CJ, Verhulst F, Jaddoe VW, Tiemeier H, & McGrath JJ (2016). Gestational vitamin D deficiency and autism-related traits: the Generation R Study. Molecular psychiatry PMID: 27895322

Machine learning applied to autism screening going big time?

Machine learning, when machines, er.. learn, is of growing interest to the autism research field. The names Wall and Duda have filled quite a few posts on this blog (see here and see here for example) on this topic and their suggesting that applying machine learning algorithms to something like autism screening and detection could cut down on time taken and resources used.

As per the publication of the paper by Daniel Bone and colleagues [1] it appears that others working in autism research are also waking up to the idea that this might be a useful area to investigate. So: "In this work, we fastidiously utilize ML [machine learning] to derive autism spectrum disorder (ASD) instrument algorithms in an attempt to improve upon widely used ASD screening and diagnostic tools." Fastidiously is such a lovely word (particularly in the context of science).

The tools in question were the Autism Diagnostic Interview-Revised (ADI-R) and Social Responsiveness Scale (SRS) (both of which have already been machine learning 'applied') and their scores "for 1,264 verbal individuals with ASD [autism spectrum disorder] and 462 verbal individuals with non-ASD developmental or psychiatric disorders, split at age 10." And the results... well, let's just say that the authors were not disappointed - or at least less disappointed than on previous research occasions [2] - as they reported on created algorithms that "were more effective (higher performing) than the current algorithms, were tunable (sensitivity and specificity can be differentially weighted), and were more efficient (achieving near-peak performance with five or fewer codes)." Indeed: "We present a screener algorithm for below (above) age 10 that reached 89.2% (86.7%) sensitivity and 59.0% (53.4%) specificity with only five behavioral codes." Sensitivity and specificity are important concepts when it comes to something like screening instruments in terms of identifying 'all' those with a specific condition and making sure that no 'not-cases' aren't mistakenly identified as 'cases'. The nearly 90% sensitivity rate presented by Bone et al on the basis of 5 behavioural codes is not to be sniffed at.

The addition of one Cathy Lord to the authorship of the Bone paper also adds an air of inevitability that applying machine learning to autism research (and practice) is going to continue and increase. Not only because of her historical connection to the ADI-R [3] (which is a hefty document in anyone's book) but also given her very prominent role in autism research history. Who knows, I might one day be blogging about more big autism research names talking about Wall/Duda things including autism screening triage by YouTube? The final question is: outside of just behavioural variables, who would be brave enough to talk genetics/epigenetics/biology machine learning as the next step in autism screening and/or assessment?

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[1] Bone D. et al. Use of machine learning to improve autism screening and diagnostic instruments: effectiveness, efficiency, and multi-instrument fusion. J Child Psychol Psychiatry. 2016 Apr 19.

[2] Bone D. et al. Applying machine learning to facilitate autism diagnostics: pitfalls and promises. J Autism Dev Disord. 2015 May;45(5):1121-36.

[3] Lord C. et al. Autism Diagnostic Interview-Revised: a revised version of a diagnostic interview for caregivers of individuals with possible pervasive developmental disorders. J Autism Dev Disord. 1994 Oct;24(5):659-85.

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Bone D, Bishop S, Black MP, Goodwin MS, Lord C, & Narayanan SS (2016). Use of machine learning to improve autism screening and diagnostic instruments: effectiveness, efficiency, and multi-instrument fusion. Journal of child psychology and psychiatry, and allied disciplines PMID: 27090613