Your Questions Answered About The 8 Sensory Systems
Read on to learn more about each sensory system and what differences in sensory processing may look like…
Q: What are the 5 primary sensory systems?
A: Sight, Hearing, Touch, Taste and Smell
Q. What are the 3 hidden senses of the sensory system?
A: 1.) Proprioceptive System 2.) Vestibular System 3.) Interoceptive System
Let’s talk about each sensory system in more detail…
Visual Processing: Visual processing includes visual acuity (how clearly you can see) and ocular motor control (how well your eyes work together). Visual acuity is how clearly you can see things up close and far away. For example, 20/20 vision is considered normal visual acuity. Visual processing also includes other important ocular abilities that involve coordinated eye muscle movement. It’s important for the eyes to work together as team. One example of eye teaming binocular vision which requires the eyes to work together for perceiving depth perception, such as when you’re going up and down the stairs. Depth perception is important for overall body coordination and eye hand coordination. Another example of ocular motor control is fixation, or visual attention. It’s essential to have steady visual attention on an object which impacts your ability to concentrate and sustain focus. Saccades are the smooth movements of the eyes which requires the coordination of both eyes in order to smoothly track, such as when reading and writing. Visual pursuits are the ability to following a moving object with your eyes only (not turning your head) such as when copying from the blackboard. It’s super important to note that a person can have 20/20 vision but also have visual processing problems. Eye strain, blurred vision, light sensitivity, if eyes not moving together, squinting or rubbing the eyes are all physical signs that indicate the need for further assessment.
Auditory Processing: Auditory processing is how the central nervous system uses auditory information. Hearing tests evaluate how well a person can hear sounds at different frequencies and to determine if there is any hearing loss. Auditory processing includes not only hearing sounds, but also auditory discrimination (which helps you know what sounds to pay attention to) and auditory localization (which helps you determine where the sound is coming from). Children with auditory processing disorder often exhibit a variety of listening challenges or complaints. Some children are over-responsive or overly sensitive to auditory input and may become distressed upon hearing certain types of sounds. Or they may have difficulty with auditory discrimination such as being able to understand speech in noisy environments (e.g. teacher talking in a noisy classroom). Children with auditory processing problems may also have difficulty following directions and telling the difference between similar sounding speech sounds. Listening is a complex process that involves both hearing and processing sounds. In the traditional classroom, good listening skills are necessary for spelling, reading and understanding spoken information to support classroom success.
Tactile Processing: Touch receptors are located in the skin and detect temperature, vibration, pain and light pressure touch. Touch processing is important to alert us of danger such as keeping your hand away from a hot surface. Tactile discrimination is the ability to differentiate information through the sense of touch. Here’s an example of tactile discrimination: If you have a nickel and a dime in your pocket, can you reach into your pocket and tell which one is the nickel without having seen it? This is using your sense of touch to notice the differences in how different objects feel. Tactile discrimination is also an underlying skill for the development of fine motor skills. Other examples of how tactile processing affect our every day lives is how sensitive we are to touch. For example, touch sensitivity impacts dressing; Some children may be sensitive to light touch and find certain type and, textures of fabric or seams on clothing bothersome. Other children may have decreased awareness to touch sensation and may not seem to notice if their hands or face are messy.
Gustatory System/Oral Motor Skills: The gustatory system is responsible for the perception of taste and flavor. Taste cells located throughout the mouth, but primarily on the tongue as taste buds, sense the 5 taste modalities: salty, sweet, bitter, sour and savory (umami). This sense of touch within the mouth helps us to feel different textures and temperatures of food. Your sense of taste and sense of smell work closely together and impact eating and food preferences. Oral motor skills are necessary for speech production, safe swallowing and the ability to consume various liquid and food textures. Additionally, oral motor skills such as sucking can have a calming effect on the nervous system. One example is when an infant or toddler is calmed down and soothed by sucking on a pacifier. Other oral motor skills such as biting and chewing can have a calming effect by providing deep pressure proprioceptive input through the jaw. Some examples include chewing gum or even eating certain types and textures of food to achieve a calming effect on the nervous system.
Olfactory Processing: The sense of smell relies upon chemical receptors in the nose that send messages directly into the limbic system, which is the center for our emotions, memory, pleasure and learning. The sense of taste and smell work together to give pleasure, such as smelling and eating your favorite food and also serve to protect us from potentially noxious situations. Some children may be overly sensitive to certain smells, such as gagging upon smelling a particular non-preferred food. Some children may seek out scents such a constantly sniffing or smelling non-food objects. This may be in part to seeking olfactory input, or in some cases if the child may be “on-guard” or hyper vigilant and uses smelling as a way to learn more about their environment. Other children may not seem to notice smells, which can become problematic for self-care routines related to hygiene.
Vestibular Processing: Receptors are located in the inner ear and are stimulated by movement of the head and input from other senses. There are different types of vestibular input, such as linear movement ( e.g. swinging back and forth), up and down (e.g. jumping) and rotary input (e.g. spinning in circles). Vestibular input is very powerful sensation and strongly influences your sense of balance, position in space, postural control, tolerance for movement, emotions and arousal level. The vestibular sense combined with the visual, proprioceptive and tactile systems are essential for well coordinated movements. Some children with vestibular processing problems may appear clumsy, easily susceptible to motion sickness or may be fearful of certain movements, preferring their feet on the ground and more sedentary play. Other children may seek out vestibular input and appear to be in constant motion by running, jumping or spinning more than usual. Well-modulated vestibular activity is very important for maintaining a calm-alert state which is ideal for emotional regulation and learning.
Proprioceptive Processing: Proprioceptive input includes deep pressure input which is obtained by lifting, pushing and pulling heavy objects including your own weight. Deep pressure touch receptors are located in the muscles, joints and ligaments and control the amount of pressure and force as well as provide a sense of body awareness. Heavy work activities and exercise that provide resistance to the muscles and joints have a calming effect on the nervous system. Proprioceptive input plays an important role in helping children who are easily overwhelmed by other sensory inputs. When proprioceptive activities are carefully selected, they can be used as calming strategies to help kids better regulate their emotional and behavioral responses to sensory stimulation or when feeling overwhelmed. Deep pressure touch and heavy work activities promote body awareness, position in space and have a calming effect.
Interoceptive System: Interoception is the ability to detect internal sensations from one’s own body. Messages from your organs are processed in the insular cortex of the brain. Interoception is important for detecting physiological functions such as heart rate and breathing, hunger, thirst, toileting. This is combined with an awareness of emotion and a subjective intensity of emotion and perception. Activities such as mindfulness, deep breathing techniques and body scanning engage the interoceptive sense.