Autism is a neuro-developmental condition that is characterised by difficulties in social interaction and communication with restricted and repetitive behaviours. It is normally diagnosed in early childhood. The prevalence of autism has been increasing over the years, affecting about 1 in 36 children aged 8 being identified with autism spectrum disorder (ASD) according to estimates from the Centers for Disease Control and Prevention (CDC’s) Autism and Developmental Disabilities Monitoring (ADDM) Networks.
Despite its prevalence, there are limited treatment options available for autism. This post explores the potential effectiveness of a treatment called Photobiomodulation, AKA Red light Therapy, which involves the therapeutic use of red to near infrared light on body tissues.
As you will read below Red Light Therapy has shown promising results in improving the key changes associated with autism, including neuronal connectivity, survival patterns, gliosis, inflammation, and gut microbiome composition. Red Light Therapy is a safe and non-invasive treatment option for individuals with autism. Please read on.
Introduction
Autism spectrum disorder, commonly referred to as “ASD”, or simply “Autism,” encompasses two primary symptoms: difficulties in social communication and interaction across various contexts, as well as restricted, repetitive behaviors, interests, and activities. Its onset typically occurs during early childhood, affecting males around five times more frequently than females, persisting into adulthood.
The clinical presentation of autism is intricate, with symptoms varying significantly among individuals diagnosed with the condition. Frequently, autism coexists with other conditions, including sensory and motor abnormalities, epilepsy, sleep disturbances, attention deficit, and hyperactivity. In recent years, the prevalence of autism has seen a notable increase, with current estimates suggesting that it affects approximately 1 in 36 individuals as mentioned above.
Within the scope of this post, our objective is to examine the potential effectiveness of red light therapy as a treatment. This therapeutic approach involves the application of red to near infrared light on bodily tissues. Those readers who are new to this therapy option should watch this great explainer video.
We aim to emphasise, via completed clinical studies,that Red Light Therapy (RLT) holds promise as an effective, safe, non-pharmacological, and non-invasive treatment option for individuals with autism.
Subsequent sections will delve into the current understanding of the neural mechanisms underlying autism. We will also discuss the existing treatments available for the disorder, which regrettably, remain somewhat limited.
Finally, we will explore the evidence supporting the idea that red light therapy can ameliorate many of the fundamental cellular dysfunctions characteristic of autism.
The Mechanisms
So here’s the deal with the brain changes that lead to autism expression. We don’t have all the answers yet, but there’s definitely a strong genetic component. We know this, like when monozygotic twins have a whopping 90% chance of having the same thing. But here’s the catch: the genetics are pretty diverse. No single genetic mutation can explain more than 1-2% of all cases. And as if that wasn’t enough, there’s a whole bunch of genes and the environment playing together, making it all super complicated. Things like what the mother eats during pregnancy; autoimmune diseases; inflammation; and even exposure to air pollutants or certain drugs during pregnancy can all make things worse. They all mess with our genes or damage the brain in ways, upping the risk and chance of getting autism.
Now, let’s talk about some of the major brain structure and function abnormalities linked to autism as illustrated below which provides a good visual.
Brain size and cytoarchitecture abnormalities: In approximately 20% of children with autism, there are general increases in the size of the cerebral cortex (ie brain overgrowth or macrocephaly), in particular the frontal, parietal and temporal areas. These early increases in size during childhood, appear to be followed by a premature decrease, presumably due to cell death (see below), from adolescence to late middle age.
Functional connectivity imbalance: There is an imbalance of functional connectivity across the brain in autism. These involve prefrontal, anterior cingulate, inferior parietal, and superior temporal cortices; these areas are associated with language, personality, task-switching, self-control, planning, working memory, social interactions and cognition, and many of the executive brain functions. It has been suggested that autism can be characterised by an increased local interconnectivity but decreased long-range connectivity.
Synaptic imbalance: The balance of excitatory and inhibitory synaptic transmission is disrupted in autism. A range of synaptic molecules and proteins become dysfunctional, such as those involved with cell adhesion. There are decreased levels of glutamine and abnormal levels of glutamate evident in blood plasma, as well as many diverse glutamate receptors across the cortex.
Gliosis and inflammation: There are clear signs of gliosis and inflammation in autism. In both animal models and in people with autism, astrocytes and microglia-particularly in the hippocampus and the cerebellum-become reactive and release pro-inflammatory cytokines that exacerbate the inflammatory condition.
Mitochondrial dysfunction and oxidative stress: In autism, there is considerable mitochondrial dysfunction and oxidative stress, particularly in the cortex, hippocampus and cerebellum. This results in increased levels of reactive oxygen species, an elevation of lipid peroxidation, abnormal calcium homeostasis and neurotransmitter imbalance, leading to dysfunctional neuronal activity and subsequent neuronal death.
Growth factors: A fascinating feature of autism is that there are elevated levels of growth factors in the brain, for example brain-derived neurotrophic factor (BDNF) in both the cortex and hippocampus and in blood sera. BDNF is a key molecule in maintaining cell homeostasis and function, and is associated with neuronal plasticity and growth. It has been suggested that elevated levels of BDNF generates synaptic dysfunction and is toxic to cells, leading to difficulties with executive function and behaviour.
Microbiome: In addition to the changes evident in the brain, autism has also been linked to alterations in the gastrointestinal microbiome. The microbiome is made up of microorganisms (i.e., bacteria, fungi, viruses, archaea, bacteriophages and protozoa) that reside, either transiently or permanently, within the gastrointestinal system. It has been described as the body’s additional or virtual organ, the key interface between food and the body.
The microbiome has a number of critical functions, including: the digestion of food; increasing energy yields; contributing to nutrition; regulating sugar use and production and fat storage; together with influencing the integrity of the gut wall lining itself.
Through its close relationship with the immune system and the large number of nerves that control the gut, the microbiome can have an enormous influence on many areas of health and well-being. Quite remarkably, during early development, the microbiome has been shown to influence brain networks and connectivity, particularly those related social interaction and behaviour; the key link in this relationship, namely the gut-brain axis, is through the far-reaching vagus nerve.
There are also indications that people with autism have altered microbiomes. For example, children with autism have been reported to have abnormal microbiome composition compared to controls; further, that autistic children often have gastrointestinal problems, with the severity related closely to the degree of behavioural disorder. The analysis of faecal matter from autistic children revealed a low relative abundance in a plethora of bacterial genera.
The consequential reduction in associated bacterial-derived genes encoding for key enzymes involved in the synthesis of GABA, melatonin and butyric acid, as well as possible alterations in gut mucosal barrier with pathological implications deriving from changes in gastrointestinal permeability, are all promising targets for novel treatment strategies
Current Treatments
Autism is an extremely heterogeneous condition and management options depend on age, symptoms, behaviours, the individual’s own perception of their neurodiversity, and the nature and intensity of co-morbidities present. In early childhood, interventions that enhance parent-child interactions have been found to be helpful, such as strategies outlined in the Early Start Denver Model, and specific approaches designed to improve language function and challenging behaviours.
At older ages, where professional support is available, the interventions are based on functional analysis of observed behaviour and evolving family situations, with a focus on intrinsic strengths and the development of more effective strategies to improve quality of life. These treatment strategies appear to only provide short-term improvements and current studies lack convincing evidence for their effectiveness in the long-term.
More recently, the role between the symptoms of autism and microbiome health has been targeted following the observation of distinct faecal and plasma metabolite profiles in children with autism. Early open-label studies have reported that faecal microbiota transplant in children with autism resulted in a shift in bacterial community in favour of the donor, indicating the possible promotion of donor microbe colonisation. Further, the Microbiota Transfer Therapy approach, consisting of a combination of antibiotics, bowel cleanse, stomach-acid suppressant, and faecal microbiota transplant, resulted in major improvements in gastrointestinal and autism-related symptoms, together with the overall composition of the gut microbiota. These observations were found to be maintained for two years following initial treatment, including an increase in bacterial diversity. Although promising, the availability of faecal transplantation and similar treatment modalities as a therapeutic option is currently extremely limited.
As for medications, there is only one currently drug approved by the United States Food and Drug Administration to treat the irritability symptoms and, to some extent, repetitive behaviours (i.e., risperidone), with some evidence supporting the benefits of aripiprazole. However, there is also evidence showing major adverse effects of these medications. There is no pharmaceutical intervention available to improve communication and social behaviours.
Other drugs, for example selective serotonin re-uptake inhibitors, can be prescribed to help manage accompanying symptoms, such as anxiety and depression, but pharmaceutical treatments of co-morbidities tend to be used with caution because of autism’s clinical complexity.
Hence, there remains a real need for the development of a broad range treatment options that can be effective in a large number of people with autism. The treatment should ideally be non-invasive and non-pharmacological, as well as being easy to use with few or no side-effects.
Red Light Therapy: The Light – Here is the Kicker !
In this context, there is a potential new treatment option that has raised considerable interest across the community. This treatment has been shown, in a range of animal models of disease, as well as in humans, to influence the functional activity of neurones, creating a balanced pattern of neural connectivity to improve the survival of neurones after stress or damage (i.e., neuroprotective), and to reduce gliosis and inflammation.
Further, it has been shown to alter and improve microbiome diversity in both health and disease. It has an impeccable safety record, with little or no evidence of side effects or toxicity on body cells, it is non-invasive and the devices are easy to use with high compliance. Taken all together, this treatment appears to “tick all the boxes” as an ideal treatment option for autism, one that is certainly worthy of further investigation. This treatment is known by several names such as Photobiomodulation Therapy; LLLT; LED Therapy but the most common one is Red Light Therapy.
Many studies from the last 70 years or so have reported that when neurones are under distress, photobiomodulation, after being absorbed by photoacceptors found mainly among the mitochondria, for example cytochrome oxidae c and/or interfacial nanowater , works to stimulate the production of ATP (adenosine triphosphate) energy that drives many intrinsic neuronal functions.
In addition, Red Light Therapy also induces more long-term cellular changes, by activating the expression of various functional and protective genes. In essence, photobiomodulation makes the neurones “healthier”, by restoring their function and making them more resistant to distress. RLT not only has a direct effect on neurones, but it also has an impact on reducing gliosis and/or inflammation . Through these mechanisms, RLT has been reported to be disease-modifying or neuroprotective in a range of animal models of disease or trauma, from traumatic brain injury to stroke and from multiple sclerosis to Alzheimer’s and Parkinson’s disease.
When neurones are healthy and functioning normally, and there is no need to activate defence mechanisms, for example, the production of more energy and/or the expression of protective genes, RLT can still have an effect. In otherwise healthy neurones, there are many examples of photobiomodulation inducing either an increase or a decrease in functional activity.
In the cortex, it has been suggested that RLT activates mechanisms that help focus attention or to help restore the overall balance of function and connectivity across any given system, particularly if it is dysfunctional. For example, in patients suffering from either traumatic brain injury or Alzheimer’s disease, both of which have abnormal patterns of functional connectivity between cortical areas, transcranial photobiomodulation helps correct these imbalances, restoring the connectivity between regions to “normal” levels
In addition, there are some early observations that RLT, when applied to the abdomen, improves the function of the microbiome in normal healthy mice, as well as those treated with a toxin to induce Parkinson’s disease. Further, when photobiomodulation is applied across the abdomen in both Alzheimer and Parkinson-induced disease mice, the death of brain cells associated with these conditions is very much reduced, indicating that an improved microbiome after photobiomodulation treatment can have a considerable impact on brain function and disease
Effect of Photobiomodulation in Autism
Primary research investigating the safety and efficacy of RLT in autism have shown promising results.
There are several clinical reports using transcranial photobiomodulation in people with autism.
Transcranial photobiomodulation (tPBM) treatment over an eight-week period has been reported in a 2022 clinical study to improve a range of behavioural measures, including social awareness, communication and motivation and a reduction in restricted and repetitive behaviours. In addition, tPBM treatment for children aged 5-17 yrs with autism over a four week period reduced irritability and other symptoms in separate study. These positive outcomes, quite remarkably, appear to be maintained for up to 12 months thereafter. Click here for those findings.
A Working Hypothesis
The working hypothesis as illustrated above is that Red Light Therapy can be an effective therapeutic option in autism by:
- Improving the behaviour and abnormal neural circuitry in the brain; we suggest that photobiomodulation will induce a more balanced pattern of functional connectivity between different regions of the brain;
- Reducing cell death, mitochondrial dysfunction and oxidative stress, gliosis and inflammation in the brain; we propose that photobiomodulation will restore normal cell homeostasis;
- Altering the composition of the microbiome and thence brain neural circuitry and thus behaviour; we suggest that microbial activity will be restored towards “normal” levels and that this will lead to an improvement in brain function.
With regard to use in humans, we suggest that, as a starting point, individuals with autism could use, on a daily basis, a transcranial photobiomodulation cap that has both Red and NIR wavelengths within the range of 630-1100nm’s; the daily use of photobiomodulation may improve the abnormal connectivity across the cortex, together with reducing the pathology and inflammation.
Several types of caps and helmets have been used successfully in, for example, patients with either Alzheimer’s or Parkinson’s disease; the parameters for these include such wavelengths, set at frequencies from 10 Hz – 40 Hz.
We should add that there would be no issue with the light from the photobiomodulation cap devices reaching through to the brain, at least to the superficial layers, including the cerebral cortex. Many previous studies have reported that photobiomodulation can penetrate from 30–80 mm of body tissues and most areas of the cortex are well within that range (~10–15 mm). Also there is evidence that Near-infra-red Wavelengths in the range of 1068-1072nm have a better ability to travel through water with less resistance than other wavelengths meaning they can reach deeper and therefore have the ability to reach the target areas with more energy and dosage leading to quicker outcomes. The PAD cap offers NIR wavelength in this range.
Further, as an indication that the light from the photobiomodulation devices can reach the brain, many studies have shown that light applied transcranially can change considerably the activity of neurones in the cerebral cortex and that the scull acts like a lens that further assists the transmission of light wavelengths.
And in conjunction with the treatment of the brain one should not be overlooking the treatment of the Gut Microbiome with Red Light therapy using a quality LED panel or flexible wrap device on a daily basis.
Conclusions
For people diagnosed with autism, there are few effective, broad range treatments available to treat the abnormal brain circuitry and microbiome environment, let alone the constellation and complexity of their symptoms. Recently, Red Light Therapy has been shown to improve, for example in many animal models of Alzheimer’s to Parkinson’s disease, some of the key alterations of brain function and microbiome composition that are also found in autism.
In addition, Red Light Therapy is very safe, with little or no evidence of side effects or toxicity on body cells, it is non-invasive and the devices are easy to use with high compliance. Photobiomodulation appears to be an ideal treatment option for autism, not to mention that it comes without the negative side effects that most of the current drugs available have on our major organs.
As always you should always check with the patients treating medical specialist if you have any concerns or questions when commencing new therapies.
