What is Modulation?

According to Webster, modulation means to regulate, according to measure or proportion.

In OT language, modulation is the ability to regulate behavior by taking in information from the environment, making correct judgments about it, and responding to it in an appropriate way.

Children with modulation issues are constantly struggling with their reactions, which are often not in proportion to the circumstances. Their nervous systems often do not allow them to respond to sensory information while remaining on an even keel. They tend to over react or under react, so they can't maintain their nervous systems in an easy state of equilibrium.

We all have individual ways of dealing with the world based on our unique perceptions, personalities, and internal chemistry. I remember a passage from the novel The Brimming Cup by Dorothy Canfield. A father in turn of the century rural Vermont, sitting upstairs in his office, is listening to his wife mediate an argument between two of their three children in the parlor. She is playing the piano while the children are singing. Their son, who is stolid and pragmatic, wants to sing "John Brown's Body Lies Amoulderin' in the Grave," while their daughter, who is sensitive and fanciful, finds both the lyrics and the tune too gruesome to bear. She begs her mother not to play it. Their mother says that since it's only fair that they each get their turn to sing what pleases them, her brother's wish should be honored. She then suggests that while they are singing the song, her daughter go sit on the back porch where she can't hear the lyrics, and since she has to pass the pantry on the way, she can slice herself a piece of cake to enjoy while she waits for them to finish.

Their father admires his wife's elegant way of acknowledging the differences in her children and making sure that their individual needs are respected and met, and reflects to himself how different in personality his children are: "Something that wouldn't cause Paul to turn a hair would just about flay the hide off of Ellie."

Modulation and behavior are based a feedback loop consisting of input, throughput, and output.

A steady stream of information about where we are in space, who and what we see, what we smell, what we hear, and what we feel comes to us through the eyes, ears, inner ear, nose, skin, muscles, joints, and tongue: Input. It is relayed to the brain, which evaluates it, attaching meaning and value to it: Throughput.

Our responses are the result of the brain's evaluation and perception of the information: Output.

A child with sensory issues is going to have ongoing difficulties with managing his output, because his input is not supplying him with correct information about what is happening in his environment. {Anyone who wears glasses and can't get out of bed in the morning before putting them on will know what this is like.} His system of throughput perceives things in a way that causes him to attach inappropriate meaning to his sensory experiences, so his responses are going to reflect that.

For example, the child with tactile defensiveness. His skin interprets light touch as a threat, a negative emotional reaction, so he may respond in a negative way, by lashing out at people who come into his personal space, wiping off kisses, and refusing hugs or eye contact. He will avoid touching certain textures which are upsetting to him, and because he is living in a fight or flight state, full of stress chemicals, he will have a hard time shifting his internal gears and being flexible. Many children with tactile defensiveness complain bitterly about things that most people would not even notice, like the tags in their clothing or the seams in their socks.

I once evaluated a little boy who could not walk to school in the mornings without breaking into tears over the tag in his shirt and the feel of the wind on his face as he walked through Central Park, often lying down on the sidewalk and refusing to continue. His behavior, or output, was dictated by the faulty throughput, which was informing him that these things were causing him harm.

A child with modulation issues tends to be either unresponsive or overly responsive, often a puzzling combination of both, and can escalate from a tuned out state to an out of control frenzy in a matter of seconds, completely bypassing the middle range. About 99 percent of modern life requires that we function somewhere in that middle range, so these children are very frequently at a disadvantage as they try to navigate all the demands and expectations of school and play.

The wiring in a sensory defensive child's brain is going to tell him that many things that we don't even register are dangerous, threatening, and painful, so his behavior is going to reflect that by being avoidant, cranky, and fearful. A child whose nervous system fails to register what is going on around him, or does not respond in a predictable way to a normal amount of information coming in, is going to reflect that in his behavior as well. He will appear to be tuned out of what is going on around him, or will seek out and try to provide himself with the sensory input he needs to stay regulated.

These children understandably have difficulty staying somewhere in the middle range, because it is so tricky for them to activate their nervous systems and keep themselves running smoothly. It reminds me of trying to start a car on a cold morning, with the engine endlessly turning and revving. The driver jiggles the key, carefully feeds it a bit of gas, the engine turns but doesn't engage. More jiggle, more gas... the engine turns and turns... the sparks fail to catch... more turn, more jiggle... nothing happening... then VROOM! All of a sudden, the engine is in full throttle.

Mostly what I see in the clinic are children whose nervous systems are under reactive to movement, and overly reactive to things like sound, smell, taste, and touch. For these children, it is hardly an exaggeration to say that a ride on a roller coaster is just about enough stimulation, while a light brush on the arm is too much.

In my next post I'll talk about ways we can help a child learn to modulate his reactions.