07/01/2021
Sensory Filtering and Sensory Overload
From what I can decipher from the research on neural connectivity, there are two primary differences in the brain wiring of people with autism. One, the long-range neuro-pathways that connect the different brain centers, allowing them to simultaneously communicate with each other, are underdeveloped. This means the person will have a difficult time rapidly processing multiple information simultaneously. What the neuro-typical brain processes simultaneously and subconsciously, many on the spectrum need to process sequentially and consciously. In other words, what we pick up intuitively (with minimal thought), those on the spectrum need to consciously think it through. As you can imagine, this slows down the processing and becomes very exhausting, leading to the brain becoming overly taxed and drained. Much of our dynamic world, especially the social world, moves way too fast for their processing speed.
Second, whereas the long-range neuro-pathways that connect the different brain centers are under-developed, the short-range neuro-connections within individual brain centers are often overdeveloped, with too many, poorly integrated, but intensively reactive neuro-connections. This leads to taking in too much information that is often intense and overwhelming (e.g., Intense World Theory). The typical brain goes through stages of “pruning,” whereby the frequently used pathways are strengthened, and the rarely used connections fade away. This allows for more refined filtering of unneeded stimulation and more selective attention to meaningful stimuli. Our brain filters out a lot of the irrelevant stimulation hitting our nervous system, so we do not become overwhelmed and can focus on what information is needed to adapt to environmental demands.
For many on the spectrum, this pruning did not occur correctly. There is an over-abundance of highly reactive neurons that are not integrated together and take in too much information (poor filtering) that overwhelms the brain, causing it to be anxious, on high alert and defensive. Whereas the neuro-typical brain has a volume control (turns down the stimulation), people on the spectrum often just have an “on/off” switch with no volume control to turn down the stimulation. The person becomes hyper-sensitive, hyper-attentive, and hyper-reactive. The world is often too loud, too bright, too much. For many on the spectrum, they must “shutdown” (processing starts to turn off) to avoid being overwhelmed. This leads to detaching oneself from what is going on around them.
When the filtering system is not working correctly, too much stimulation floods the brain, overwhelming the brain centers with too much stimulation and making it difficult to sort out and attend to what is relevant. Three main challenges can occur: (1) Too much information coming in, (2) lack of ability to turn down the intensity (volume) of stimulation, and (3) distorting the stimulation, making it difficult to identify what it is (e.g., hear it but cannot understand it). The brain becomes overwhelmed, panics, and sets off its fight or flight response. When overwhelmed, the brain loses its ability to function; it becomes disorganized, coping skills decompensate, and panic sets in. If overload occurs slowly, the brain may start to shut down to avoid the overload, or if the brain becomes overwhelmed too quickly, it will panic and meltdown. Everyone is different in how this plays out for them, but it is a scary, helpless tidal wave of panic for many of them.
When you combine the poor long-range connections between the brain centers with the overdeveloped, but poorly integrated, short-range connections within the brain centers, you essentially have a brain that has delayed processing due to poor communication between the brain centers and over-sensitivity to sensory stimulation. Essentially the neuro-typical world (1) moves way too fast and (2) too much (too loud, too bright, no filtering). The brain becomes hyper-aroused and hyper-reactive, making the world chaotic, confusing, and overwhelming.
Given this, how do we help? Although many strategies, the few main principles to remember are:
1. Slow the world down! Slow yourself and the world down, giving the child time to adequately process what is expected. Try to match the flow of information to the processing speed of the individual. Allow the child to pace the speed of information. If the child starts to freeze, blank out, increases stimming, or becomes oppositional, then chances are the expectations are too hard, too much, or coming too fast for the child.
2. Turn the world down! Remember that the brain is not filtering stimulation well; it takes in much more than it needs, cannot turn it down, is hyper-sensitive, and has difficulty integrating multiple stimulation simultaneously. Assume that our world is simply too loud and overwhelming for the child, causing the child to be on high alert, defensive, and hyper-reactive. We must be very alert to how much (noise, visual stimulation, smells, busy activity, etc.) and how intense (loud, bright, etc.) the stimulation is that surrounds the person. Then, try to turn it down or provide filters (sunglasses, earplugs, etc.) to block out the intensity of stimulation.
3. Simplify information and expectations: Break tasks and projects down into simple, sequential steps and make expectations clear, concise, and concrete (literal). Use visual strategies if possible and plenty of demonstration, repetition, and guided participation.
4. When in doubt, change our expectations: When things are not going well, and the child is pulling away, being oppositional, or shutting down, assume that our expectations and information are either too fast, too hard, or too confusing for the child. The demands are stronger than their current abilities to handle them. This places the responsibility for change on us, not them. Back up, break it down, slow it down, and offer assistance as needed to match the demands to the processing abilities of the child. Learning will become not only possible but also fun. The world will be less scary and more comfortable to handle. The child will begin to feel “safe, accepted and competent.”