Why do Autistic Kids Stim? …and Strategies To Help

If you have a child with autism, then a big part of their day to day life can be taken up by stimming. Stimming is a type of repetitive or stereotypical behaviour that is common in autism and is short for self-stimulatory behaviour. It is one of the symptoms of autism that is recognisable from a distance and includes hand flapping, spinning and rocking. Stimming is also a part of the diagnostic criteria for autism. Stims are almost identical to the tics that are experienced in Tourette’s Syndrome and are often involuntary which means they are difficult to control.

Stimming isn’t necessarily a negative trait and can be a core way a person with autism is able to self-regulate emotionally. But stimming should be addressed when it’s disruptive to others, is potentially harmful or interferes with quality of life.

Examples of stimming include:

  • staring at objects with lights or movement
  • zoning out/gazing into space
  • repeatedly blinking
  • looking through the corner of their eyes rather than straight on
  • humming and making other noises
  • tapping hands or feet together or on objects
  • finger clicking
  • covering and uncovering ears with hands and possibly tapping ears
  • repeating words or phrases from films or tv shows
  • rubbing or scratching skin repetitively
  • spinning, rocking, pacing, hand flapping
  • licking things, or sucking fingers or thumb
  • unusual smelling or sniffing of things

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Why do autistic people stim?

Some autistic people stim to release internalised pressure from within their body and it can relieve their anxiety. Stimming can also help them concentrate better and help to distract them from sensory overload. Sometimes autistic people stim just because they are excited, or it feels good to them at that time and is comforting. Stimming can also be triggered by boredom and can be a way to deal with difficult thoughts and feelings. Most stimming is harmless and often helps the child to function better, zoning out and repeated blinking does not have a large impact on their daily life.

For some autistic children, stimming indicates to their parents or carers that they are in distress, uncomfortable or reacting their environment around them. Knowing this can help the person who is caring for them, to move them out of the situation to help them settle. Stimming is an important unconscious communication method for autistic children, and it can be helpful to a parent or carer to tune in with their child’s needs. As the behaviours are repetitive it is often easy to identify what is a stim and parents will get very familiar with their own child’s stims and be able to look out for them.

The downside of constant stimming is that it is harder for the child to focus in on anything else during these episodes and this may hinder progress in social interaction, communication and learning. This is because stimming is very distracting and is a meditative method of zoning out from the life around them. One of the measures to gauge whether autism therapies are helping a child is when their stimming is much reduced, and they can access more from their surroundings.

Why stimming can turn into self-injurious behaviours

Some stimming behaviours can be extreme and end up with the autistic person harming themselves. This could include self-harm like head banging, obsessively picking at skin until it bleeds and hitting or pinching themselves repetitively. These self-injurious behaviours (SIBs) have been reported in more than 30% of children autism in clinic-based studies.

Research has found that SIBs may be due to an enhanced expression of pain – often gut pain or headaches. It is thought that some autistic people experience an anaesthesia-like effect when they stim which means that they do not feel any pain while engaging in the stimming behaviour – so possibly some of these behaviours may be a way of self-medicating. Also, the release of endorphins from this behaviour may provide the individual with a euphoric-like feeling which they like. This theory has been supported in studies where medications that block the binding at opiate receptor sites like naltrexone can successfully reduce self-injury.

Interestingly in the early 1990s a researcher called Mary Coleman studied a group of autistic children who regularly poked their eyes and also had low levels of calcium in their blood. When these children were given a course of calcium supplements, the eye-poking decreased substantially and at the same time their language and communication improved.

Self-injurious behaviours that include head banging, slapping ears, hand biting, chin hitting, scratching face or arms and sometimes knee-to-face contact have also been linked with epilepsy and seizure activity in the frontal and temporal lobes of autistic people. It is important to get a referral to a neurologist if this is happening regularly and there seems to be no other obvious cause.

Communication problems have also been associated with SIBs and may be a form of frustration, especially when a person has poor receptive or has poor expressive language skills. Much energy has also been put into the research linking social links to self-injury and the frequency of self-injury can be controlled by manipulating social consequences. In a nutshell, positive attention can increase the frequency of self-injury, whereas ignoring the behaviour can decrease the frequency of the SIBs.

It’s important to be aware of the link between stims and SIBs, especially if these become are dangerous and to do your best to work out the root cause of this distress.

Link to the Autonomic Nervous System and Vagus Nerve

The autonomic nervous system controls all the bodily functions that are done unconsciously such as breathing, digestion, urination and heartbeat as well as the fight or flight body response. The vagus nerve functions plays an important role in the autonomic nervous system and the vagus nerve is made up of neural fibres and it influences major organ functions and their relationship with the brain. Also think of the vagus nerve as a super-highway linking our brain and our gut. The vagus nerve is also responsible for some sensory activities and motor information for movement within the body which are a core part of stimming.

Autistic children often have problems with their gut such as constipation and intestinal pain and also have sensory sensitivities to social interaction, loud noises and light. This is all linked to the vagal pathways and how this part of the brain stem controls the face and head muscles. The vagus nerve can influence the person’s ability to be vocal, can possibly affect their facial expressions and can also dictate gut motility. In autistic children, this vagal function may be hampered and downregulated which means they cannot control their physiological state which makes it almost impossible for them to effectively socially interact.

Autistic children usually have autonomic dysfunction which means they may find it hard to sleep and have a lack of heart rate regulation when exposed to stressful or overwhelming stimuli. The autonomic nervous system is responsible not just for breathing, heart rate and other unconscious bodily functions but also expression of emotions, social engagement and vocal communications. When the autonomic nervous system is out of sync, then stimming can occur.

Autistic children having an autonomic dysfunction means they can struggle with these core areas of their life and they can react differently to stimuli and can get overwhelmed by many situations that would be absolutely fine for neurotypical people with a perfectly functioning autonomic nervous system. Because of this increased stress in situations this causes them to stim to help calm themselves down and to find another focus to take them away from the situation they are uncomfortable in.

Nutrients That Can Help With Stimming

So, what can nutrition do to help support stimming? The nutrition approach focuses in supporting both vagal tone and the autonomic nervous system and to help reduce the feeling of overwhelm and sensitivity to the environment so the person with autism. It is important to run thorough metabolic laboratory tests to understand the specific and individual nutritional needs of each person and rarely would someone need to take all of the nutrients below:

Thiamine (Vitamin B1)
The vagus nerve originates at the medulla, which is located in the brainstem, and links the brain to the rest of the body. This is one of the regions in the brain susceptible to thiamine deficiency. A lack of thiamine can lead to inefficient metabolism within the medulla which leads to abnormal activity of the vagus nerve and autonomic dysfunction. This has numerous downstream effects on the gastrointestinal system and can lead to constipation and gut pain. Thiamine in also needed to synthesise the neurotransmitter acetylcholine which is important for language and learning.

Thiamine food sources include beef, liver, pork, pulses and legume, milk, eggs, nuts, seed, oats, breakfast cereals fortified with vitamin B1, oranges, peas and yeast. Often laboratory test results show a marked need for thiamine and so a food supplement is added in until the levels have been optimised.

The sympathetic branch of the nervous system uses acetylcholine to relay messages but also uses epinephrine and norepinephrine from the adrenal gland. The parasympathetic nervous system wholly relies on acetylcholine to function properly and this is important for proper digestion, gut motility, salivary flow, tear formation and good bladder function. Acetylcholine is also important for learning and memory which is key to speech and educational progression.

Foods that contain acetylcholine include liver, butter, eggs, peanut butter as well as vegetables and wholegrains.

Research is now finding that gut bacteria helps to improve brain activity by affecting the function of the vagus nerve. In murine studies, the probiotic strain Lactobacillus Rhamnosus has found to make positive changes to the GABA receptors in the brain which reduces stress hormones and leads to less depression and anxiety and was via signals from the gut to the brain via the vagus nerve. Lactobacillus rich foods include yoghurt, kefir, sauerkraut and sourdough bread.

N Acetyl Cysteine
N Acetyl Cysteine (NAC) is the precursor to glutathione which is our master antioxidant and helps to modulate inflammation and helps to regulate excitatory brain activity. A small study at Stanford University found that NAC lowered irritability in autistic children as well as reduced these children’s repetitive and self-stimulatory behaviours. This has been replicated in other small studies and a meta-analysis published in September 2020 confirmed its safety and has potential to help with the core features of autism.

Sulforaphane (Broccoli sprouts)
Sulforaphane is found in broccoli, Brussels sprouts, cauliflower and cabbage and it is believed to increase the gene activity that help cells protect themselves from damage caused by inflammation and oxidative stress.

One 2019 study has found sulforaphane has a profound effect on the central nervous system and should be considered to prevent the progression of a wide range of neurological presentations. The sulforaphane has also been found to be helpful in managing depression and anxiety as well as chronic and persistent neuropathic pain. One study showed that the broccoli sprouts improved the analgesic actions of morphine.

Many autistic people have been found to be deficient in magnesium and this is a critical mineral to help with a wide range of health needs and can help to relax muscles, induce sleep and also help with constipation. It is often taken in conjunction with Vitamin B6 to give greater support to the central nervous system.

The NatureDoc neurodevelopmental team specialises in autism and is able to organise thorough laboratory testing to understand the root cause of stimming and self-injurious behaviours. Do be in touch if you would like to investigate this further.



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