Written by Stella Chadwick for the Autism Eye Magazine.
Regardless of the label your child has, amongst the broad spectrum of ASD, almost all disorders are related to the abnormal functioning of two key areas of the brain; the Reticular Activating System (RAS) and the limbic system.
RAS is responsible for wakefulness and processing of all information, both being sent and received by the brain. All of our senses (except smell, which goes to our brain’s emotional centre) are wired directly to this area. Think of RAS as a bouncer at a nightclub that works for the brain. It prevents sensory overload by making sure our brain does not have to deal with more information than it can handle. The limbic system is the emotional centre of the brain and is responsible for the way a person behaves, the level of anxiety and aggression that is felt, as well as the mood that is experienced.
What has always fascinated me is that symptoms of sensory processing disorder fluctuate from day to day and sometimes from hour to hour. This means that the brain is responding differently at different times given the same information, suggesting that the response is not static. This is huge – because it means that children with sensory processing disorder may not have a brain disorder but a disorder in the way information is fed to the brain.
There are a number of therapies, which have been shown to help with sound sensitivity, such as Auditory Integration Therapy. However, in this article, we will be focusing on the roles of nutrition and individual biochemistry in sensory integration disorders and the practical steps that can be taken to address any imbalances.
Sensory development occurs in the first 3 years of life. From birth to 3 months, infants rely mostly on touch and feel which means that the sensory system requires slow speed and hence slow myelination – a bit like the speed of old “dial-up”. Myelin is like the plastic coating of an electrical wire, providing an insulating layer and is essential for the proper functioning of the nervous system.
Between 3 and 12 months, the visual system needs a lot of support and this is where “ultra speed broadband” is required as there is significant need for myelination. Between 12 and 36 months kids start to move about a lot more so the vestibular system, responsible for balance, needs significant support. The vestibular system in particular is very sensitive to any disturbances to myelination and any environmental assault at this time can have a significant impact on development. It is therefore not surprising that many children regress during this period.
Genetic predisposition may play a part but the evidence seems to suggest that the role of genetics is negligible. In many cases, the key contributing factors appear to be environmental toxins and viral load, which interrupt myelination. If these offending toxins and viruses stay in the system then the insulin-like growth factor IGF-1 is depleted (IGF-1 helps reproduce and regenerate cells).
Reduced IGF-1 appears to trigger continual re-activation of neurotropic viral agents causing fluctuating inflammation in the sensory organs or their nerves – this results in the brain not being able to integrate sensory systems and leads to a changing and confusing clinical state. Please see table 1 for a list of neurotropic viruses.
Toxins can have a significant impact on neurological function. In their 2006 review Harvard environmental epidemiologist Philippe Grandjean and Mount Sinai Medical School paediatrician and epidemiologist Philip Landrigan identified five widely used industrial chemicals as “developmental neurotoxicants.” Such chemicals can contribute to developmental brain disorders such as autism. The five were; lead, methylmercury, polychlorinated biphenyls, arsenic and toluene.
In addition, the 2006 report identified more than 200 industrial chemicals that cause brain damage in adults. The authors warned that many of these might likewise cause developmental brain disorders if exposure occurred during pregnancy or early infancy. These toxins are present in the environment in many forms: as a soil component, water contaminant, as well as dust particle in urban areas.
High levels of these toxins can be found in industrial areas, near mines and factories, as well as near battery recycling centres. Mercury is a key component of amalgam fillings, regularly administered to both children and adults in the UK. In Table 2 you will find the list of the organ systems often affected by toxic exposure to substances we are faced with on a daily basis.
Addressing sensory processing disorder requires a multifactorial approach. Cleaning up the diet and reducing environmental toxic load can be significant for some but as ever, there is no one-size-fits-all in autism and a thorough investigation is necessary to help identify and deal with the toxic burden and viral load and support mitochondrial function in order to help restore function from the ground up.
All herpes group of viruses such as:
Varicella zoster (chicken pox)
|Organ/ System||Exposure Examples|
|Respiratory||asbestos, radon, cigarette smoke, glues|
|Skin||dioxin, nickel, arsenic, mercury, cement (chromium), polychlorinated biphenyls (PCBs), glues, rubber cement|
|Liver||carbon tetrachloride, methylene chloride, vinyl chloride|
|Kidney||cadmium, lead, mercury, chlorinated hydrocarbon solvents|
|Cardiovascular||lead, carbon disulfide, arsenic, cadmium, ozone, vinyl chloride, carbon monoxide, noise, tobacco smoke, physical stress, nitrates, methylene chloride|
|Reproductive||lead, carbon disulfide, methylmercury, ethylene dibromide, polychlorinated biphenyls|
|Haematologic||arsenic, benzene, nitrates, radiation|
|Neuropsychological||Tetrachloroethylene (dry cleaning fluid), mercury, arsenic, toluene, lead, methanol (used to produce a variety of chemicals, including formaldehyde and acetic acid. Formaldehyde is added to adhesives used in the wood industry, such as plywood and laminates. Formaldehyde is also a key component of resins used to coat paper and plastic products. vinyl chloride (used to make PVC – polyvinyl chloride)|
|Symptoms caused by a mineral imbalance of key minerals|
|MAGNESIUM: inability to sleep, irritability, sensitivity to noise, muscle soreness or spasms, anxiety and depression, heart palpitations, unusual tiredness, cold extremities, difficulty concentrating, food and chemical sensitivities, poor appetite, poor short-term memory, carbohydrate cravings, constipation, frequent cavities, thyroid problems|
|IRON: anaemia, fatigue, pale skin, shortness of breath, cold hands and feet, inflamed or sore tongue, brittle nails, poor appetite, cravings for non-food items such as ice or dirt|
|ZINC: poor attention span and motor disorders, skin problems such as; acne, eczema, dry, scaling skin, hair loss, poor immune system, slow wound healing, poor sense of smell and taste, fussy eating.|
|COPPER: fatigue, arthritis, paleness, always feeling cold, anaemia, brittle bones, frequent infections, muscle and joint pain, poor growth, hair loss, unexplained weight loss, easy bruising, skin inflammation and sores|
|IODINE: depression, lethargy and fatigue, memory problems, recurrent infections, cold extremities, brain fog, thinning hair, constipation, shortness of breath, impaired kidney function, muscle weakness and joint stiffness, thyroid problems|