Monday, December 31, 2012

Polyvagal Theory, Sensory Challenge and Gut Emotions

Have you heard about Dr. Stephen Porges' Polyvagal Theory? The theory, already 20 years old,  replaces our old notions of how the sympathetic (fight/flight) and parasympathetic nervous systems (rest and recuperation) help to keep us calm, alert and safe. The area covered by Polyvagal Theory is huge. It impacts the way we understand our nervous system, senses, emotions, social self and behaviors. We see diagnoses like autism, sensory modulation disorder, borderline personality and others, in a new light.

Polyvagal Theory claims that the nervous system employs a hierarchy of strategies to both regulate itself and to keep us safe in the face of danger. In fact, it's all about staying safe.

Our "highest" level strategy is a mechanism Porges calls social engagement. It is a phenomenal system - connecting the social muscles of the face (eyes, mouth and middle ear) with the heart. You knew that your heart came alive with social interaction, and it's true! This system is regulated through a myelinated branch of the vagus nerve. In evolutionary terms, this is our most evolved strategy (mammals only) for keeping ourselves safe. We use this all the time to clear up misunderstandings, get help, plead for forgiveness, and so on.

The next mechanism, or strategy, is fight or flight. It's regulated by the sympathetic nervous system. This system is our fall-back strategy when social engagement isn't a good fit. (Think of seeing someone sneaking up on you!) Note that freeze is not a part of fight or flight.

Our freeze option is primal and is a remnant of our reptilian past. Freeze is a great strategy for turtles and lizards, but it's usually a bad idea for humans - think of fainting. Therefore, we typically use it last, when social engagement and fight/flight aren't going to work for us. But there are good uses for freeze. During severe injury, it shuts us down and turns off our registration of pain. We also make use of it during sex, and it helps women regulate pain and response to pain during labor.

Now these systems appear to work in tandem. The social engagement system puts the brakes on the other (fight, flight, freeze) strategies, thus keeping our heart and body active while we work through a situation. The social engagement system will release the brakes to engage a different response to the environment (i.e. running) if engagement doesn't help to get us into a safe situation.

What Can Go Wrong
We want our nervous system to operate using the social exchange most of the time. It is our most evolved way of being. It is restful and healthy because it allows our gut and other organs to do their job uninterrupted.

However, some of us are programmed from an early age to work from a fight/flight mode. Think of people who are sensory sensitive and recoil from sound, touch, smell or taste. Think of people with autism (in this case, the face to heart connection is not working). Think of people with borderline personality, depression and perhaps other disorders, too. When we are not able to work from our social engagement strategy, then we revert to a modified fight/flight strategy, which puts us in high alert. If we use too much of the fight/flight or freeze strategies, we may end up with gut issues because the gut comes to a halt and we stop digesting food during fight/flight activation.

The Polyvagal Theory has gained great acceptance over the years as pieces of it are shown to hold under laboratory findings. From a psychological viewpoint, it provides us with a rich understanding of self-regulation in the body. From a sensory processing viewpoint, it informs our understanding of sensory modulation.

If you are unfamiliar with the topic, check out the many articles on Dr.Porges' website. The most comprehensive article is The Polyvagal Perspective, and it is published here on the NIH Public Access site. It contains the physiological underpinnings of the theory as well as perspectives on  development, emotions, trauma and many other topics. There is a short video of it here.

Sensory Connection
Two researchers looked at a biological marker of the social exchange system, RSA, in typical children and in children with sensory modulation issues. RSA is the measure of high-frequency fluctuation in the heart between heart beats. It is a window into the social exchange system. The researchers found that children with sensory modulation issues have a lower level of RSA than their peers, meaning that these children are better prepared to put the breaks on social strategies and instead use fight-or-flight strategies.

As part of the study, the children were (each in turn) given a sensory challenge. The chairs they were seated on tilted backwards unexpectedly. The level of RSA was monitored in each child throughout the incident. The RSA of typical children dropped quickly and then stayed low for a short time. The children with poor sensory modulation skills had a very brief drop of RSA and a quick rebound to their RSA baseline.

This implies that children with sensory modulation symptoms use different strategies to handle safety-related situations than their peers. At this time, it is harder to draw greater conclusions since we do not have an easy-access window into the fight/flight system or the freeze system. With time, we'll get a better understanding of this. The article can be found here.

Perhaps the most interesting new work making use of the Polyvagal Theory is the work of A. D. (Bud) Craig. Mapping our emotions, this is what he found. (Read about it here.)

Emotions arise from feelings in our organs and gut. The feelings are sent via the vagus nerve to the Anterior Insular Cortex (AIC) in the brain. (There's a lot going on in the vagus nerve - think of it as a cable with lots of separate wires.) The AIC captures feelings over time  and stores them as snapshots of feelings. This is our working emotional memory. These feelings are massaged and integrated with the social exchange to give us both an emotional response to the world around us as well as a safety-driven strategy.

Think of this: I am relaxing in a lounge chair on the beach. I feel safe. Suddenly, a beach ball hits me. My fight or flight instinct kicks in and the sympathetic nervous system stops everything that's happening (i.e. digestion) in my organs and gut. The gut passes the feeling of stoppage as "alarm" to the brain. This translates in the brain to fear and my body is set in motion. I quickly turn and see it's a ball and that a child is nearby and smiling at me. My social engagement strategy puts the breaks on my fight/flight response and also calms my heart. I smile at the child. This sends a sense of relief to my gut and it in turn sends a "warm" feeling to the AIC. My heart is still pounding from the surprise, but my response is guided by compassion.

In the above scenario, we specifically looked at a situation with a challenge to safety. But in fact, we spend much of our time worrying about safety. Unless I am completely safe, listening to quiet music in a locked room, I will most likely have safety challenges to respond to. The challenge may be from the scary book I am reading, or from the sense of anxiety I feel when I drop a spoon on the floor. Almost any activity will involve the combined interaction of the various strategies. The bottom line: we are constantly adjusting ourselves to meet the world. Polyvagal Theory gives us a look at how this works.

This is pretty complex stuff - and the theory is still in flux. It changes with each new study that looks at the implications of Polyvagal Theory on our response to the world. It is going to impact research greatly in the years ahead. As I mentioned at the beginning, Polyvagal Theory adds a new dimension to how we see autism, sensory issues and other disorders and will, I think, inform our interventions for those disorders in a big way.

  1. Porges, S. W. (2008, February). The Polyvagal Perspective. NIH Public Access, PMC1868418
  2.  Schaaf, R. C., Benevides, T., Blanche, E. I., Brett-Green, B. A., Burke, J. P., Cohn, E.S., Koomar, J., Lane, S. J., Miller, L. J., May-Benson, T.A., Parham, D., Reynolds, S., Schoen, S. A.  Parasympathetic Functions in children with sensory processing disorder. Front Integr Neurosci. 2010; 4: 4. Published online 2010 March 9. doi: 10.3389/fnint.2010.00004
  3.  Craig, A. D. (2009). Emotional moments across time: A possible neural basis for time perception in the anterior insula. Philosophical Transactions of the Royal Society of London. 364,1933-1942.

Friday, December 28, 2012

Criteria for Screening SMD with the Sensory Profile

The time over the holidays is when I typically read everything I can get my hands on as a way of updating my workshop and keeping current in general. I sometimes run across elusive information such as this item.
Here is the criteria that Dr. Miller and her colleagues use to determine whether a child has Sensory Modulation Disorder (SMD). They screen using the Short Sensory Profile and if ...
  1. Total Test score of less than 3.0 SD (standard deviations) below the mean; or
  2. Less than 2.5 SD below the mean on two or more subtests; or
  3. Less than 4.0 SD below the mean on one subtest
.... then the child has SMD.

That leaves it to you to figure out the means using the manual :((( ..... or come back in a few weeks and I'll have it here. :)))

Update, January 9, 2013:  I have not been able to locate published values for 2.5 SD and 4.0 SD of each of the SSP sections. It is a difficult mathematical exercise to produce the numbers without all of the data. So let's estimate some of these numbers for 2.5 SD. I will have to beg off estimating 4 SD at this time - it's a pretty tricky calculation.

The numbers for 1-2 SD and 2-3 SD are on p.66 of the Sensory Profile Manual. By the way, I am going to estimate 2.5 SD somewhat conservatively.

Estimates2.5 SD3 SD
Tactile Sensitivity166
Taste/Smell Sensitivity73
Movement Sensitivity62
Underresponsive/Seeks Sensitivity156
Auditory Filtering125
Low Energy/Weak145
Visual/Auditory Sensitivity104
Total Score8937

Scoring examples:
1. If a child has a tactile sensitivity score of 16, he is 2.5 standard deviations (SD) below the mean. If he has a score of 2 on movement sensitivity, he is 3 SD below the mean. Since he has 2 scores of 2.5 SD or lower, he qualifies for a diagnosis of SMD.

2. If a girl's total score is 37 or less, she is 3 SD below the norm and qualifies for the SMD diagnoses.



1.       Miller L. J., Reisman J. E., McIntosh D. N., Simon J. (2001). An ecological model of sensory modulation: performance of children with fragile X syndrome, autistic disorder, attention-deficit/hyperactivity disorder, and sensory modulation dysfunction. In Understanding the Nature of Sensory Integration With Diverse Populations, Smith S. Roley, Blanche E. I., Schaaf R. C., editors. , eds (San Antonio, TX, The Psychological Corporation; ), pp. 57–88.

Thursday, December 27, 2012

2012 Journal Tidbits - Autism

Here are some study findings from the Journal of Autism and Developmental Disorders - one of my favorite journals - that struck me as worth sharing. By the way, you have until Dec. 31st (2012) to browse this journal for free on line.

 1. Is picky eating due to sensory issues or due to food rigidity?
This article suggests that some picky eating problems are due entirely to rigidity in the child's food selection patterns. Treatment in this case is motivational. A child is told they will try a certain food. They are offered a choice of reinforcers (rewards). If they eat the food, they receive the reinforcer. They are also rewarded with accolades.  If they do not eat the food, they do not get the reinforcer.

When trying a new food, the authors followed a hierarchical pattern similar to Kay Toomey’s SOS Approach method:
  1. Touches the food
  2. Puts food to the lips,
  3. Bites the food, bites
  4. Puts in mouth but does not swallow
  5. Chews but does not swallow
  6. Swallows reluctantly
  7. Accepts food without signs of displeasure.
After18 weeks, children were spontaneously requesting the new foods they had tried. The three children in the study, Ken, Robbie and Daniel accepted 5, 9 and 8 new foods respectively at the completion of the 22 week study.

2. What causes self-injurious behaviors in autism? The seven risk factors for self-injurious behaviors are 1) poor sensory processing, 2) low cognitive skills, 3) poor language / communication skills 4) poor social function, 5) age (18 mo. - 19 yrs.), 6) rigid behaviors and 7) gender. However, these factors account for just 29% of the self-injury cases seen, with sensory being the greatest factor of these (5-7%). The authors hypothesize that chronic pain and psychosocial factors may play a large factor in the remaining 71%. Clearly, there is more work to be done.

3. Is there a relationship between anxiety and repetitive behaviors? Yes, repetitive behaviors appear to be a cause of anxiety. "It is possible that, for some individuals, interventions focused on a reduction of behaviors, promoting flexibility and reducing repetitive play may consequently reduce anxiety." See the next article for more on this.

4. Are there interventions for quieting repetitive behaviors? Yes, if the child's behavior can consistently be triggered. For example, give a child with autism six cars, he will line them up. That behavior is triggerable and can be replaced with functional behavior. How about if the behavior is not triggerable? That's a harder problem. Not only do we not have interventions, we are not doing the research to look for them.

  1.  Boyd, B. A., McDonough, S. G., Rupp, B., Khan, F.,& Bodfish, J. W. (2011). Effects of a family-implemented treatment on therepetitive behaviors of children with autism. J Autism Dev Disorders,1330-1341.
  2.  Boyd, B. A., McDonough, S. G., F., & Bodfish, J.W. (2012). Evidence-based behavioral interventions for repetitive behaviors in autism.J Autism Dev Disorders, 1236-1248.
5. Do children with autism also qualify for anxiety disorder? Yes, the diagnoses overlap often in children and young people (40-45%). Specifically, in children with high functioning autism, anxiety should be treated (medicine or stress reduction techniques) as a way of supporting other methods of increasing social skills.