Sensory Processing Disorder (SPD) is a condition in which the brain has difficulty receiving and responding to sensory information from the environment. SPD is typically observed in children who react hypersensitive to stimuli such as sounds, textures, lights, or smells.
The theory is that SPD does not only affect the conscious spectrum of sensory information, but the sensory nervous system at large. Most of these hidden hypersensitivities remain unnoticed in children, though, and only become relevant at a later stage, where they manifest in the form of various mental dysfunctions. Besides dormant symptoms since childhood, SPD can also be acquired at a later stage in life as well.
Sensory Signal Noise
The primary assumption is that SPD is caused by a signal noise in the sensory nervous system, which distorts or prevents sensory signals from reaching the brain. This can be caused by genetic, or environmental factors, but also induced by illnesses. On the conscious level, this signal noise can express itself in various light neurological symptoms like visual snow, paresthesia, tinnitus, palinopsia, or the susceptibiliy to ASMR. These sensory distortions are prevalent in the entire sensory nervous system and affect both sensory inputs from the senses as well as internal signalling to and from various organs.
External Stimuli Lead to Dysfunction
Under this assumption, the brain and other organs cannot react properly to disruptions of the physiological balance through external stimuli. This causes the body to temporarily go into a state of physiological imbalance, hence into dysfunction, until the influence either stops or is absorbed by the body without adjustments by the responsible organ. External stimuli can include food, weather, conscious body movements, emotional stress, and possibly other physiological processes in connection with the sex and age of the patient.
The Sensory Noise Nullstate
While the signal noise prevents sensory information from reaching their destination inside the body, the signal noise itself can be misinterpreted as fake sensory signal by the receiver. This creates a sensory nullstate which differs from the physiological balance and means that dysfunction can occur even without any external disruptions, because the organs react to a physiological imbalance that is not there. In this case the dysfunction will only disappear, when external stimuli mimicking the nullstate are affecting the body.
Wide Variety Of Dysfunctions
Given the multitude of possible influencing factors, the specific calibration of the nullstate and variations in the strength of the signal noise, a wide range of dysfunctional states can arise. They can include fatigue, chronic sleep problems, hyperactivity, confusion, anxiety, aggravation, and various other physiological and mental conditions including some forms of migraine. The dysfunctions are then exacerbated by seemingly random shifts in these states depending on which and to what extent external stimuli are affecting the body in a given moment.
Superficial Symptom Treatment
The possible consequences from the signal noise are of such a complexity that it becomes close to impossible in many cases to derive concrete diagnosis, let alone a tangible description of what is exactly wrong with the patient, and what may trigger the particular dysfunction. Consequently, conventional treatments tend to focus on mere neurological supression of the symptoms in the brain, but fail to address that many neurological disorders may as well be rooted in the sensory nervous system.
The assumption of a signal noise in the sensory nervous system in connection with SPD offers a viable alternative explation and treatment opportunities for disorders like chronic fatigue syndrome, fibromyalgia, ADHD, OCD, anxiety disorders and possibly many other mental dysfunctions.