Yoga therapy and autism: OK but "better trials are required to confirm the positive impact"

I approach the findings reported by HM Vidyashree and colleagues [1] with my typical critical eye but perhaps also with a sense of 'receptivity' to the idea that yoga training *might* be useful for some people diagnosed as being on the autism spectrum. My receptivity is there because: (a) "yoga is a safe and effective way to increase physical activity, especially strength, flexibility and balance" according to the NHS guide to yoga, and (b) putting aside any (non-testable) spirituality or the like associated with yoga use, I'd like to think that some of the aims of and techniques used in yoga are similar to that seen with some of the martial arts. As well as being a fan of the martial arts - Shotokan karate is my particular hobby - certain martial arts already have some quite positive 'history' in the context of autism in the peer-reviewed science arena (see here and see here for examples). We'll see what we'll see...

The Vidyashree paper had the aim: "to investigate the effect of yoga intervention on short-term heart rate variability (HRV) in children with ASD [autism spectrum disorder]." HRV is basically what it describes: "a measure of the variation in time between each heartbeat." That variation is controlled by something called the autonomic nervous system (ANS), which basically regulates various bodily functions typically minus conscious input from ourselves. From what I gather, a low HRV is something to be avoided; as people talk about a higher HRV being linked to better cardiovascular fitness as well as increased resilience to stress (whatever that means). You probably won't be surprised to hear that HRV has been previously talked about with autism in mind [2], albeit with a lot more investigation required (see here).

So: "50 children (38 boys and 12 girls) with ASD were recruited from Swabhimaan Trust, Palavakkam, Chennai." All were diagnosed with an autism spectrum disorder (ASD) and "were grouped into ASD with yoga intervention (n = 25) and ASD without yoga intervention group (n = 25) by simple lottery method." HRV was recorded via an ECG (electrocardiogram) on two occasions, before and after intervention/non-intervention. Said yoga intervention - in 40 minute sessions - was apparently delivered "every day in the morning" over 3 months. That's quite a few sessions...

Results: bearing in mind 10 participants and 5 participants from the yoga and non-yoga groups respectively were excluded from the data analysis side of things, a few details were observed. So: "There is a significant reduction in mean HR [heart rate]... in the ASD children after yoga intervention." As a group, the mean baseline HR for the yoga group was around 90 beats per minute. After intervention, this dropped to under 80 beats per minute. At the same time, the non-yoga group showed an increase in their mean heart rate over the same period. Other results, more technical results, are also included in the Vidyashree paper which I believe translate into measuring HRV [3]. I can't pretend to know all the hows-and-whys of those results, but with a cursory reading of the literature in this area, am willing to go along with the authors' conclusions that results: "showed significant improvement" coinciding with the yoga intervention.

Obviously a lot more study is required in this area before any grand claims about yoga or anything else are made in the context of autism. The Vidyashree results were firmly focused on HRV following yoga and said nothing about how yoga may/may not have affected some of the behavioural profiles associated with autism for example. Likewise, all the stuff about lower HRV being linked to greater resilience to something like stress have not been fully analysed in the context of the current results either. All of this comes alongside the methodological issues that accompany the Vidyashree: an open-trial, yoga vs. no yoga, etc.

But I still remain interested in the potential of something like yoga in many contexts including that related to autism...

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[1] Vidyashree HM. et al. Effect of Yoga Intervention on Short-Term Heart Rate Variability in Children with Autism Spectrum Disorder. Int J Yoga. 2019;12(1):73–77.

[2] Daluwatte C. et al. Atypical pupillary light reflex and heart rate variability in children with autism spectrum disorder. J Autism Dev Disord. 2013 Aug;43(8):1910-25.

[3] Shaffer F. & Ginsberg JP. An Overview of Heart Rate Variability Metrics and Norms. Front Public Health. 2017;5:258. Published 2017 Sep 28.

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Bowel issues in autism may cluster with other symptoms

"Clinicians should be aware that gastrointestinal problems, anxiety, and autonomic dysfunction may cluster in children with ASD [autism spectrum disorder] and should be addressed in a multidisciplinary treatment plan."

So said the findings by Bradley Ferguson and colleagues [1] who, continuing an autism research theme (see here), "examined the relationship between gastrointestinal symptomatology, examining upper and lower gastrointestinal tract symptomatology separately, and autonomic nervous system functioning, as assessed by heart rate variability and skin conductance level, in a sample of 120 individuals with ASD." Authors concluded that approaching half of their cohort "met criteria for functional constipation" and that said bowel issues might not necessarily just be a stand-alone finding.

I had expected these results based on a previous presentation at IMFAR 2015 (see here). That also one Micah Mazurek appears on the authorship list of the Ferguson paper builds on her previous discoveries (see here) in this area and more generally (see here and see here). Yup, real gut-brain stuff; and when it comes to the often disabling (yes, disabling) effects of something like anxiety in relation to autism (see here), further data potentially pinpointing areas for possible intervention. Mmm, I wonder (see here)...

One very interesting detail included in the Ferguson data was the observation that: "a history of regressive ASD or loss of previously acquired skills" might also be an important variable when it comes to heart rate variability and "lower gastrointestinal tract symptomatology." Regressive autism is something that I'm particularly interested in on this blog (see here for example) and the idea that in amongst the many and varied plural 'autisms', one or two 'types of autism' might not necessarily be all 'pre-programmed' (see here). What the recent data from Ferguson et al might imply is that further studies on bowel issues and anxiety according to symptom onset might be indicated (bearing in mind previous studies have not been too favourable when it comes to things like regression and bowel problems in autism).

The bottom line: yet again, various comorbidities may be over-represented alongside a diagnosis of autism (see here) and when it comes to 'explaining' psychology and behaviour in relation to at least some autism, we ignore other potentially important somatic manifestations at our peril (see here). And speaking of comorbidity and autism, take a gander at a recent paper from Richard Frye & Dan Rossignol [2]...

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[1] Ferguson BJ. et al. Psychophysiological Associations with Gastrointestinal Symptomatology in Autism Spectrum Disorder. Autism Res. 2016 Jun 20.

[2] Frye RE. & Rossignol DA. Identification and Treatment of Pathophysiological Comorbidities of Autism Spectrum Disorder to Achieve Optimal Outcomes. Clin Med Insights Pediatr. 2016; 10: 43–56.

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Ferguson BJ, Marler S, Altstein LL, Lee EB, Akers J, Sohl K, McLaughlin A, Hartnett K, Kille B, Mazurek M, Macklin EA, McDonnell E, Barstow M, Bauman ML, Margolis KG, Veenstra-VanderWeele J, & Beversdorf DQ (2016). Psychophysiological Associations with Gastrointestinal Symptomatology in Autism Spectrum Disorder. Autism research : official journal of the International Society for Autism Research PMID: 27321113