Sensory Modulation refers to the brain’s ability to regulate its own activity, essentially managing “how much” of each sensory input to “tune into” at any point in time. Throughout each day, individuals are exposed to a multitude of sensations, each with varying intensities. Efficient modulation allows the individual to filter out irrelevant information in order to attend to, and respond to, those stimuli which are most pertinent.
Sensory Over-Responsiveness: Individuals who are over-responsive to sensory stimuli generally have a heightened sensitivity to sensory stimulation in comparison to most people, as if constantly being bombarded with information. As a result, these individuals often experience a “fight, flight, or fright” response to these sensations which their bodies feel either too easily, too quickly, or too intensely. For example, being touched unexpectedly or a hearing a loud noise may cause them to startle more than most people. Due to their over-responsiveness, the child may try to avoid or minimize sensations, such as by withdrawing from being touched or by covering their ears in efforts to avoid loud sounds. The following are a few behaviors that may be observed in individuals with over-responsiveness:
May demonstrate increased arousal/activity level
Lack of focus
May appear to be aggressive
Sensory Under-Responsiveness: Individuals who experience an under-responsivity to sensory stimuli are generally passive or withdrawn, as they are unable to acknowledge or respond to stimuli of the usual intensity available in their sensory environment. Consequently, they tend to appear either quiet or disengaged; or they may seem clumsy or move in ways that are not graded efficiently (i.e. utilizing too much or too little force for activities such as petting a dog, opening/closing a door, or writing with a pencil) due to their under-responsiveness to tactile and deep pressure input. These individuals often have decreased overall body awareness in that they may not perceive stimuli such as temperatures that are either too hot or cold, or they may not sense pain in relation to bumps, falls, cuts, or scrapes. It should be noted that there is also a separate classification of under-responsive children, who can often appear as though they are “sensory seekers/cravers” (described below), in that they appear hyper rather than low arousal. What sets these individuals apart from sensory seekers, however, is that when the right amount of input or combinations of input are provided, these children are able to organize their behavior. The following are a few behaviors that may be observed in individuals with under-responsiveness:
Decreased arousal/activity level
May crave movement experiences, particularly proprioceptive opportunities
Sensory Seeking/Craving: Individuals who are sensory seeking/craving are very active and seem to never fatigue in their pursuit of sensory input. Unlike children with under-responsive tendencies (who become more organized with increased input), no amount of input is enough for these individuals with sensory seeking/craving tendencies to organize their behavior. Sometimes categorized as the ‘movers and shakers’, they are continuously on the go, whether it is running, jumping, bumping, crashing, etc. These children often have the desire to touch everything and do not acknowledge personal space. Many of these children receive labels of Attention Deficit Hyperactivity Disorder (ADHD) and Attention Deficit Disorder. The following are a few behaviors that may be observed in individuals with sensory seeking/craving tendencies:
Poorly modulated attention
Risk taker/ impulsive
Need for constant stimulation
Although the aforementioned categories are three unique and separate distinctions, individuals often exhibit mixed presentations. In essence, a child may actually experience all three of the described modulation deficits in regards to various sensory systems. For example, this individual may be over-responsive to tactile and auditory stimuli, under-responsive to vestibular inputs, and overall present with sensory seeking/craving behaviors.