Sensory Integration Issues and Gut Reactions
last updated 8.25.05
Autism and the GI Tract
Considering 'Sensitivity' Issues
Food, Taste, Texture, Pain
Timothy Buie, MD - pediatric gastroenterologist
[works at Harvard and is active clinician]
Presentation at the Minnesota Autism Society of America conference April 25, 2003. My notes are indicated following the slide texts.
Dr. Buie began by telling how he got into the area of treating autism earlier in his career as a pediatric gastroenterologist. An adult with autism was brought to him because the caretaker didn't know where else to go. Then more and more people were brought. He started treating their gut problems and got a bit better. He found that many of the gut problems were more advanced than usual most likely because caretakers just couldn't tell the person with autism was suffering with real physical ailments because they didn't express them in a typical fashion. Although at first he thought there may be a simple pattern to 'autistic gut problems' he found this was not true and there was as much variability as in a typical population.
Slide 1: The Brain-Gut Connection
- Every known neurotransmitter present in the brain is present in the gut
- The gut is the most 'nervous' organ in the body or is that nervy? It's got a lot of innervation!
- The gut has independent mechanisms from the brain to regulate actions [enteric nervous system ENS]
Slide 2: The brain runs the show
- Most data surrounding autism are brain based neurotransmitter and anatomy data
- Structural findings are seen at pathology of brains not seen by MRI or CT scans
- Known neurotransmitter differences in children with ASD compared to unaffected children [see Margaret Bauman about this]
[Notes: He related a little about what is known about neurotransmitters and different measuring techniques.]
Slide 3: Brain regulation
- Many researchers have evaluated the impact of endogenous opioids on the brain and how they may account for some of the neuro-behavioral findings seen in ASD [autism conditions]
- Abnormal opiod regulation has been associated with self-stimulatory and self-injurious behavior, abnormal pain responses
[Notes: He made a point of saying the 'opioid peptide' line of thought with autism was a very unproven theory and quite controversial. There are neurotransmitters in gut and brain and they do not necessarily work together. Extrapolating from what is known about brain reactions and assuming they are exactly the same in the gut can get you in trouble.]
Slide 4: Opioid Effects
- The GI tract is profoundly affected by endogenous and exogenous opioids.
- Opioids cause alterations in motility of the GI tract, secretion of fluid, and acid in the gut and the sensitivity of the gut to stretch and contraction.
[Substances classified as opioids or having opioid properties vary. They are not all identical. Opioids from food are not morphine and vice versa. Some opioids are benefical and needed so the body operates properly and the nervous system functions well.]
Slide 5: Other Neurotransmitters
- Ongoing research connects acetylcholine, GABA and serotonin to ASD problems.
- All affect GI motility and sensitivity in a variety of ways.
[Notes: Because there are so many neurotransmitters in the gut, it is not easy to separate what is speculated to be a reaction from food versus a reaction with one of these other neurotransmitters. Dairy affects the promotion of serotonin. Some people say dairy may have a constipating effect due to opioids, but it could also be due to increased serotonin activity...or even that dairy is high in proteins, which have a constipating effect.]
Slide 6: The Second Brain
- The GI tract 'is' a second brain which is somewhat independent of, but interaction with, the brain in the cranium
- Independent of guidance from the head, the gut can secrete, contract and respond to stimuli such as distention.
- Communication is a two-way street up and down from brain to gut
[Notes: The brain and gut communicate with each other but work independently. Besides chewing and swallowing, and timing of elimination, your digestive tract pretty much runs on its own.]
Slide 7: Plasticity of Nerves
Nerves have a language similar to speech. The alphabet of this language is the neurotransmitter. The location and amount of neurotransmitters secreted are the language spoken to the brain. Our nerves learn the language by repetitive stimulation.
[Notes: Repetitive stimulation is how sensory integration therapy works. Nerves respond to simulation. Repeating stimulation helps nerves 'learn' and grow and develop new pathways. They 'learn' to respond a certain way to certain types of stimulation.]
Slide 8: Plasticity
Repetitive messages of pain from a location establishes a trained pathway [and a trained response, sometimes an automatic response].
Example: Mrs. Brown - When Mrs. Brown calls, and she does often, I expect she will talk about Steven [for a long time giving all the details of his condition]. Through repetitive painful events [her long laboring conversations], when I hear her name, her home telephone number flashes to my brain and I call my wife to tell her I'll be late.
Nerves learn too, through repeated painful events or other messages, pathways are formed.
Slide 9: Brain-Gut Interactions
Signals from gut to brain: about 90% in this direction
Signals from brain to gut: about 10% in this direction
Slide 10: Pain
- Pain is perceived in the context of the event.
- There is a local response to pain at the site of pain (example: close your finger in door, your arm jerks back suddenly and you instantly grab your finger without thinking about it...you might scream Yeow! at the same time). This is a local response, or sudden assistance to the pain site.
- The pain message is sent from the pain site to the brain.
- Then the brain sends a response with facilitory and inhibitory circuits. (example: close your finger in door, brain realizes finger has been smashed, sends painkillers to pain site, and whatever else is needed to 'fix' the injury, finger may be sore for next couple of days but it is lessened than initial attack)
[Notes: There is a local or 'micro' response to pain, and a non-local or 'macro' response. The micro response does not depend on signals and feedback from the brain whereas the macro response does involve signals from the brain.]
Slide 11: Pain
- Pain is activated by inflammation, trauma, infection.
- It can be reinforced (reinforcement of event)
- A 'pain memory' is established.
[Note: There are different types of pain reactions. You may experience different symptoms or behaviors based on which one is happening or which the body 'remembers'.]
Slide 12: Allodynia
- Pain occurrence -> then the reason for the pain revoles (so there should be no pain)
- However the neural cirsuitry has been altered to allow pain to persist with lower or no inciting stimulus. This is called allodynia and the 'false pain' sensation cycles back and is registered as pain occurance once again (start at beginning).
[Note: Think of 'the old foot-ball injury' where someone hurts their knee or arm in college. It heals but there is a nagging pain that resurfaces from time to time throughout their life. The nerves responded to a real pain at some time and responded appropriately, but the response 'stuck'. Even with the actual pain source gone, the nerves still react like it is there.]
Slide 13: Visceral Hyperalgesia
- Painful Stimulus -> Magnification of message.
- There can be a magnification of the pain message. This magnification can be termed 'increase in sensitivity'. Or explained as the system over-reacting. After an original painful event, a much smaller event might cause a painful reaction that is out of proportion to the actual event. Example: if the first event or two was eating a lot of crunchy food resulting in cramping of the stomach and gagging, there may be a magnification of the sensation. Afterwards, a very small amount of that crunchy food, or any type of crunchy food, may cause the same huge cramping and gagging when it is eaten.
[Note: This is commonly seen with a child who seems to gag on anything cold, or anything chewy, or anything crunchy, or with certain smells, etc...no matter how small an amount is given, the system has the 'pain memory' and reacts inappropriately. The reaction can be triggered by smells, sights, textures, temperatures, even sounds.]
Slide 14: Irritable Bowel Syndrome
- Irritable bowel syndrom (IBS) is a motor and sensory condition of the colon.
- There is altered pain sensitvity to bowel distention but not generalized sensitvity
- Painful stimuli outside the bowel are actually tolerated better than in patients without IBS; these people are not wimps.
[Notes: Irritable is a real physical painful reaction the person feels. He is not over-reacting even though his colon is. The colon has a learned wrong response which can occur by various paths and is out of the control of the person. This is a different condition that a person who has detectable lesions, inflammation, or bacterial overgrowth in the colon. The colon needs to be re-trained to respond correctly for proper comfort and digestion. He said a bout or so of constipation and painful distention can set the pattern. Sensory therapy may help. Notice that there is no food involved in this at all, but you can imagine a parent trying to determine which food is causing the bowel problems.]
Slide 15: Irritable Bowel Syndrome
- This is a sensory and motor condition.
- A trigger of bowel distention may cause the sensory message of pain but it also triggers the motor effect of contraction or spasm
- This promotes diarrhea or constipation in some patients.
[Note: Seeing as how Dr. Buie had two slides on this one point, he seemed to really want to get it across.]
Slide 16: Sensory Integration
'Non-painful' stumulus -> Magnification of sensation to an extreme and unpleasant level...(PAIN?)
[Note: The point here is that there is a real physical event that results in a physical event that may be painful or at least uncomfortable. The person is reacting appropriately to the physical event as they feel it. It is the sensory response system that is acting inappropriately. It is definitely not just bad behavior or an attempt for attention. Unfortunately, children and especially someone with a communication impairment, is not able to accurately express this. Often it takes the form of poor behavior, 'over-reacting' to what others around them perceive as a little thing, stimming, tantrums, or other behaviors. Example: light tough causing a person to jerk away their arm like it had been hit. The nerves are responding inappropriately. Something like the brushing technique helps because it re-trains the nerve response.]
Slide 17: Location, location, location
- Where the primary trigger of an event occurs may form the foundation of later symptoms.
- If history of allergic colitis as an infant, pain may continue in colon after resolution of the condition. [Note: the pain response is remembered]
- This premise has been supported recently in 'post-infectious' IBS
[Notes: This last point is when a patient has lesions or measurable infection. Then they are treated and the lesions or infection is cured, yet the patient continues to have symptoms. The nerves have become sensitized to the sensory input and react as before. It reacts with a pain response even though there isn't a response to now. Hopefully, the system will un-learn the pain response on its own with time and/or therapy. Some meds can faciliate this.]
Slide 18: Location
- If preceding sensitization at skin or leg, ongoing sensitivity may persist there.
- The brain has an anatomical image of the body (homunculus).
- The affected area of the body will have a neural picture in the brain and a record of the trauma (e.g. phantom limb pain)
- Repeated or prolonged injury enhances the image.
[Notes: If you injure the same spot or close by again, the picture is engrained deeper. See the allodynia effect.]
Slide 19: Is pain a fair model when discussion autism?
- Who knows?
- Do all children who are autistic have wiring that was remodeled to alter pain sensitivity, sound sensitivity, touch sensitivity?
- The concept that nerves are plastic and moldable serves as the tenet of autism therapies (ABA, OT, SI, Floortime, etc.)
[Notes: He basically said we don't know how extensive this may be applicable in autism. Maybe it varies by individual. But 'molding' and re-training the nerves is a foundation of many of the therapies which have very good results in working with autism conditions.]
Slide 20: Historical Brain/GI Connections
- Down syndrome
- Gastroesophageal reflux
- Cornelia DeLange Syndrome
- ? Celiac Sprue
- ? Food Allergy
[Notes: This is a list of conditions we know have a brain-gut connection of some sort. He went through the next slides kind of quickly without elaborating much on them.]
Slide 21: Down Syndrome
- Chromosomal abnormality
- Known abnormalities structurally in the brain
- Knwn association with autism (~8%) of down syndrome children have autism
- Known association with GI problems (~30%) with gastroesophageal reflux
Slide 22: Gastroesophageal Reflux
- In infancy this is more common in boys, twins, premature brains
- Felt most commonly to be a function of delayed stomach clearance, which is controlled, for the most part, by the brain.
- It is a developmental condition not evident at birth, like ASD, that generally develops between 2 weeks and 2 months of age.
Slide 23: Cornelia DeLange Syndrome
- Congenital malformation of the brain
- Known autism freuency (high)
- Frequent GI issues (GE reflux may be as high as 90%)
- Personal observation: self-injurious behavior diminishes dramatically when treating reflux.
Slide 24: Celiac Disease
- Known GI disease with genetic predisposition (gluten sensitivity)
- Known associated neurological symptoms include depression, ataxia, CNS calcifications, peripheral neuropathy among others
- Abnormal neurological symptoms have been attributed to nutrient deficiency.
[Notes: The jury is still out on what exactly is going on or causes celiac disease. Some of the neurological or immune system reactions are not due to the celiac eating gluten directly, but result from the disease impairing the villi and thus nutrient absorption. Malabsorption or deficiencies results and this is the cause of the observed symptoms and problems.]
Slide 25: Food Allergy
- Crook described multiple neurological problems in children with food allergy including anxiety, behavioral abnormality, and even psychosis which he reported resolved with food restriction.
- Incidence of food allergy is cited at 8% in general pediatrics, best small study in ASD states 36% incidence
[Note: This is William Crook of the Yeast Connection. Buie was talking about the general impact of diet. He said there was a noted connection between neurology, food, and behavior. Buie emphasized here that the point to note is not the exact numbers or specific foods in question, but that the incidence of food intolerance/GI problems appears greater in the autism population than among controls, or a typical population. Some studies say higher numbers and some lower, but not all these studies had adequate or appropriate controls. And the numbers may give the wrong impression. But in general, food can affect neurology, and people with autism seem to have a higher incidence of that. Past this, more proper research is needed for specifics.]
Slide 26: Food Allergy
- If allergy is a problem there may be several mechanisms by which it contributes to symptoms in ASD [autism conditions].
- Inflammatory effect
- Chemical mediator release and altered neurotransmitters.
[Notes: He emphasized again that the exact mechanisms are not yet known even though some purport they have various theories. Might be that inflammation plays a large part, or leaky gut, or altered neurotransmitter activity (such as serotonin) in the gut. One thing that favors the serotonin view is because the SSRI medications seem to be among those most effective for many people with autism conditions. The common foodstuffs grains, dairy, and proteins would also greatly affect serotonin. Gut integrity influences serotonin.]
Slide 27: How might GI Issues Impact Autism
- altered pain sensation from inflammatory conditions such as GE Reflux, acid damage, inflammation from infection, allergy or idiopathic cause may promote symptoms
- altered pain sensation from mechanical issues such as bowel distention from constipation, spasm from irritable bowel symptoms may promote symptoms
[Notes: Notice that these are related to physical reactions in the gut and not food chemistry issues - peptides, phenols, sugars, etc.]
Slide 28: Other Issues
- Nutritional impact may be real
- Tryptophan deficiency is well shown to alter neurotransmitter levels and there by contribution to CNS modulation
- Other nutrient or vitamin deficiency may account for the same issues especially in the setting of GI diseases known to cause malabsorption (celiac, food allergy)
[Notes: Tryptophan is the precursor to serotonin. The neurotransmitters affect one another. Some people consider serotonin the master transmitter. He mentioned that various nutrients or causes may lead to the same thing...such if have a GI disease, most any GI problem will lead to malabsorption whereby any number of nutrients can become deficient. You might give one nutrient, see a few positives and conclude that the particular nutrient you pulled off the shelf and gave first was The One to treat autism. This is an erroneous application of cause and effect.]
Slide 29: 'All this and I can't tell you about it'
- Add communication impairment to the problems these children suffer and it makes the sorting process for an individual child daunting.
- We need to learn the language of pain.
[Notes: There is a lot of work and research to be done. We do the best we can.]
Slide 30: Data regarding GI issues in ASD are coming
- Two large studies looking at the frequency of GI issues will show a frequent intersection of the problems.
- The reasons for the connections remain unclear or at least not yet supported by medical literature.
- Set aside cause/effect questions.
[Notes: He made a point of saying that several sources are working on getting data. There is a lot of very basic science that needs to be done. There are several popular theories floating around claiming that Such-n-Such causes Autism, or This Food affects Autism in Such-n-Such Way. None of that is known for sure, or for whom. Once again mentioned the popular opioid theory that is not holding up well and is unsubstantiated, but people are relying on what they speculate is cause and effect as the basis of treatment.
He said not to get so hung up on a few certain foods. Test all types of foods equally. If you suspect a problem food, take it out for 1 month and then put it back if no improvement is seen. He said it is important to challenge any eliminated food each 6 months to see of the sensitivity has 'recovered' to normal, which it can by itself. Do not load up the diet with any one or two particular foods because this can cause the gut to be overly sensitive to that food, whatever it is. It is a common error for parents to get frightful of casein and gluten, then load up the diet with soy, corn, or rice...then months later, they discover the child has a sensitivity to those foods as well. It is typically the pattern to try to eliminate numberous foods and you get yourself into a big nutritional mess.]
Slide 31: A New Resolution
- GI doctors and neurologists as well as parents of affected children need to be open to possible GI problems in chilren with ASD
- Regardless of the GI connection to causation in autism, these children have a right to care and evaluation appropriate to the symptoms.
[Notes: Said the main thing to do while researching the gut issues are to realize that people with autism have just as many physical problems, if not more gut problems, as a typical person but the discomforts may not be expressed the same. Often any symptoms are taken to be a characteristic of autism. He said a person with autism can also have diabetes, or a heart condition, or a gastro problems that are totally unrelated to their autism. And whether any of these things are directly related to autism or not, that shouldn't prevent the person from getting the care they need.
No matter how you feel about how these problems came to be or what caused these problems, the autism person should have proper medical care for those problems the same as anyone else. He said that he does not think, or know of at this point, any gut problems that CAUSE autism conditions. And that correcting the gut problems alone will not cure autism. But being in discomfort would likely make symptoms much worse just as anyone feels worse when they are ill. And if he could help the person with autism feel better and have a better quality of life, he would be very happy.]
Here is a summary of the questions, answers, and other comments.
1. What do you think about mega-doses of vitamins and other supplements? Generally, not in favor of these. Particularly the B vitamins and vitamin A need to be watched. A little above Recommended Daily Allowance is okay, but otherwise take care. The B vitamins affect neurology and can be neuro-toxins in high amounts. Vitamin A can be over-dosed quickly and builds up to harmful levels. Not particularly in favor of all the excess supplementation. Working with a nutritionist is good.
2. Should we take dairy out of diet? See above responses on not treating dairy as any more problematic or less problematic than other foods. Test foods for 1 month to see if any progress. Otherwise don't worry about it. Same with gluten or other foods. Opioid theory remains unproven and there are studies showing that isn't the answer. (He named 4 studies I am trying to track down in full.) If dairy or gluten removal yields positive improvements, do not assume it is an opioid reaction, could be various reasons. Challenge any food removal every 6 months because nerves can de-sensitize on their own in that amount of time.
3. How can you re-train the colon or internal sensory response system? Sensory integration therapy may help. System may self-regulate on its own. Some medications help. Liked some of the older less used medications such as amitryptiline which treats for pain and helps sleeps. Regular sleep helps 'calm' and regulate the nervous system in whole, and can help with the internal gut nervous system as well. Some people see good results with Depakote (I think that is a seizure med) and some other older ones. Said don't be surprised if you mention one of these meds to a doctor and he discourages you and suggests a 'newer' one. The newer ones don't have some of the properties that are most helpful for the autism need.
[Note: I can attest to this. My doctor said that amitryptiline used to be used as an antidepressant at higher doses, but for pain and sleep disorders at lower doses. The newer SSRIs are much better at treating depression but have no pain control properties now. So they keep the ami for use with migraines, 'phantom' pain with surgeries, with cancer treatments, and other such uses.]
4. Some children are hypersensitive to different colors or smells of food. These can be real pain mechanisms at work and not the child being difficult
[Notes: When I was little I could just gag at the smell of banana. I had to leave the room of someone else even peeled a banana. When I was 20 I decided this was silly and I needed to overcome my banana problem. I help my nose and started by choking down one slice. The next day I repeated with 2 slices, next day with 3 slices, until I could tolerate banana. Now I eat banana all the time and rather like them. Without realizing it, I was re-training my nervous system with a different response.
Another example: For years I didn't like and refused to eat carrots, pumpkin, squash, and oranges. What do these have in common? Was this an intolerance of lutein that required a lutein-free diet? Was it an intolerance to beta-carotene or phenols? Squishy foods? It turns out that I get nausous at the color orange. Can't wear orange clothing, get a headache if someone's house or store has much orange in decor. As an adult I work on this. My husband makes a delicious pumpkin pie so that has helped. Hiding it with whipped cream helps too.]
Children get migraines too. Most people recognize that if an adult gets a migraine, they are hyper-sensitive to the point that they need to be in a very dim room (blocks out lights and reduces color), that is quiet (reduce sound input), lie down (reduce bodily movement), and get very nauseus or vomit on an empty stomach. Now think about a child going through the same thing. Maybe several times. And the caretakers probably don't realize this is going on, and the child is kept in the atmosphere of typical sensory input (which is way to much given the illness). Then their nerve system develops a learned hyper-sensitive pain response.
5. What do you think about taking probiotics for diarrhea or constipation? He mentioned probiotics being very helpful for most people. They do many beneficial things including providing digestive enzymes into the body, help control pathogens, and many other things. Probiotics are basically safe and reasonable thing to try. However, about 15% of people with autism (and maybe the general population) can't tolerate any type of probiotic supplements. So if you can't tolerate them, don't force the issue, some people just cannot for no special reason, then just skip them.
6. Can you comment on mercury affecting the gut? He said that he thinks that there is not sufficient evidence to say that Heavy Metal X CAUSES this gut problem or that gut problem...or even autism, but pursuing that as an area of research is a valid course of action. Said we must be very, very careful about establishing cause and effect. You might have two things happening which appear related, and even might be, but it is a leap to say this CAUSED that. What he sees is patients with varied gut problems and varied histories with no distinct pattern. He talked about proper controls.
Example: If you are a GI specialist and 10 people with autism come to see you, you might find that 9 out of 10 have constipation and 5 out of 10 have esophageal reflux. You might conclude that 90% of people with autism have gut problems or constipation and 50% have reflux. This would be wrong. It is only 9 of the 10 patients that chose to come to you because they had symptoms of a definite gut problem. This is not 90% of the total autism population. There might be 10,000 people who did not come to see you and are just fine. The reality may be that gut problems occur only in very exceptional cases. Then, you would need to compare that with the percentage of non-autism people who may or may not go to see a doctor. He said that even with the studies they do have, better controls are needed in the future to properly evaluate what they are looking at and make more refined conclusions.
Example 2: If you do a study and look at 100 children with autism and find 30% have constipation and food allergies, you need to also look at 100 children without autism to find out if this is higher or lower than 'the norm'. And consider the environment. When he started he was brought nearly a dozen people with autism and most have reflux and ulcers. He initially thought that most people with autism had ulcers and that was what we should look for first. This was erroneous. As it turned out, the institution where the adults stayed had an outbreak of the bacteria H. pyloria. Because of the close living quarters and the fact we simply didn't know much about H. pyloria at the time, a lot of people were infected. Later, he looked at patients from other areas and other states, and there was no exceptionally high incidence of reflux or ulcers in autism at all.
Many of the commonly reported gut problems in any population have a number of causes or can result from a number of events. The sensory issues bear notice because particularly with very sensitive kids, the child exhibits certain symptoms yet the GI tests all come back normal. Food eliminations nor typical treatments by the GI specialists do not yield improvement. The child is not 'imagining' this discomfort, and needs to be helped, but sensory therapy or pain management might be the answer.
[Note: Many of these core concepts, as well as some of the not often heard details, are contained in the book Enzymes for Autism and other Neurological Conditions. It was very nice to hear a presentation like this. Dr. Buie talked about the mechanism of pain response in the gut which was extremely interesting. A response may be a physical sensory reaction and not a food chemistry reaction. The book, The Second Brain, is a bit technical with laboratory experiment designs but describes the finding of the extensive serotonin reactions in the gut.]