A: SPD is a complex, neurophysiological condition that affects developing children (and adults who were not treated in childhood).
- Sensory input, either from the environment or from the body, is poorly detected, modulated, or misinterpreted, resulting in an atypical response.
- Symptoms occur within a broad spectrum of severity from feeling overwhelmed or bombarded by sensory information; to seeking out intense sensory experiences.
- Poor sensory discrimination impacts motor performance and leads to difficulties with coordination.
- While most of us have occasional difficulties processing sensory information, for children and adults with SPD, these difficulties are chronic, and they disrupt everyday life.
~ Lucy J. Miller
The Brain Body Connection
Our bodies are hard wired with receptors to detect sensory input from our environment as well as from within our bodies. This sensory input is travels through our nervous system to our brain where it is processed and interpreted.
How you respond to this input really depends upon how your brain has processed and interpreted it. Your brain automatically decides whether or not the sensation should be responded to, ignored or if it poses a threat. Your response is governed by how your brain processes the sensation. This process occurs without thinking as the brain filters out what’s important and what’s not important to pay attention to.
Everyone’s body chemistry, medical history and genetics are unique, which means that we all may interpret sensory information a bit differently but the overall circuitry is functioning well.
For example, let’s say you’re at school and the bell rings. The majority of children have gotten used to the sound of the bell, which means their brain has habituated to the noise so they hear it, but do not become startled or upset by it. On the other hand, one student’s reaction to hearing the bell elicits a startle reflex, and he may become distressed upon hearing the bell, resulting in behavior such as covering his ears or crying. This does not necessarily mean he has SPD, but it is important to understand that the reaction to auditory input will likely affect his performance and ability to focus in the classroom.
The 8 Sensory Systems
Most people can easily identify the 5 sensory systems (vision, hearing, taste, smell and touch), but you actually have 8 sensory systems. The types of sensory input we receive from our environment are visual, auditory, tactile, olfactory, gustatory, proprioception (deep pressure touch and body awareness), vestibular (balance, movement and position in space) and interoception. Let’s do a quick review of the brain-body connection and the related sensory systems
- Sensory receptors in the eyes send messages to the optic nerve which sends sensory messages to various sites in the brain where the information is perceived, sorted out and linked up to other senses.
- In addition to acuity, oculo-motor, eye teaming, visual tracking and visual sensitivities all play an important role in visual processing.
- Sensory receptors in the ear send messages to the brain and central nervous system to make sense of sounds, which sounds to attend to and where the sound is coming from.
- The discrimination of sound helps to pay attention by filtering out background noise. A child may overreact or under-react to sounds in the environment.
- Listening is a complex process that involves both hearing and processing sounds.
- Smell travels directly into the limbic system which is the center for our emotions, memory, pleasure and learning.
- Our sense of taste and smell work together to give pleasure and also serve to protect us from a potentially noxious situation.
- Be aware of any taste and smell sensitivities.
Gustatory System/Oral Motor Skills
- Taste, touch, texture and temperature receptors are located in the mouth.
- Oral motor activities such as sucking can comfort and help a child self-regulate.
- When combined with deep pressure input, oral motor input provides a calming effect (e.g. resistive chewing, biting).
- Touch receptors are located in the skin and detect light touch, temperature, vibration and pain.
- Touch discrimination is important for fine motor skills, body awareness and alerts us of danger.
- Touch receptors are located in the joints and muscles.
- Deep pressure and heavy work activities promote body awareness, position in space and have a calming effect.
- Receptors are located in the inner ear and are stimulated by movement of the head and input from other senses.
- Vestibular processing impacts balance, position in space, tolerance for movement, emotions and arousal level.
- Well-modulated vestibular activity is very important for maintaining a calm-alert state.
- Interoceptive awareness of the state of one’s own body is important for detecting physiological functions such as heart rate and breathing, hunger, thirst.
- This is combined with an awareness of emotion and a subjective intensity of emotional and perception.
- Activities such as mindfulness, deep breathing techniques and body scanning engage the interoceptive sense.
Perhaps you’re thinking of your own child? Or perhaps there’s a student in your classroom whom you suspect has sensory issues?
What is your biggest challenge right now?
It’s SO important to keep an open mind when observing behaviors at home and in the classroom… ask yourself if certain behaviors you observe are due to a maladaptive response to sensory input, a behavioral issue or a combination of both? Are there certain triggers, events, environments, times of day or patterns that you notice when problems seem most likely to occur? An occupational therapist trained in Sensory Processing can help you answer these questions!
Miller, L. (2014). Sensational Kids: Hope and Help for Kids with Sensory Processing Disorder