Foundational Sensory Challenges
The Tactile System
- (Touch, Temperature, Pain)
The tactile system is made up of tiny receptors in the skin. Different parts of the body have different amounts of receptors. For example, the hands have a highly concentrated amount and are therefore more sensitive to touch sensations. The receptors help tell the body to pull away if something is too hot or sharp. Students with ASD may have a hyposensitivity or hypersensitivity to touch or being touched. They may not react to normal sensations such as heat or a bug crawling on them (Heflin and Alaimo 2007). They could also be overly sensitive to objects such as tags in clothing or seams in socks.
The Proprioceptive System
- (Motion or Position of the Body or Limbs)
The proprioceptive system provides us with awareness of joint position and movement. This helps to ensure appropriate fine and gross motor coordination (Boutot and Myles 2011). The proprioceptive system regulates the amount of pressure needed to pick up paper or apply to a pencil when writing. It also helps modulate movements such as walking, sitting, holding, dressing, writing, chewing and so forth (Heflin and Alaimo 2007). Students with ASD with proprioceptive issues appear clumsy, play roughly unintentionally, slouch, and break crayons and pencils when writing. They may seek out deep pressure touch to help alleviate stress created by sensory stimulation.
The Auditory System
The auditory system allows us to hear sound, process what we are hearing, discriminate between sounds, and focus on foreground sound while tuning out background sound (Boutot and Myles. 2011). Students with ASD may have a strong reaction to subtle noises such as the ticking of a clock or become extremely agitated and upset with loud noise such as the fire alarm. According to Helfin and Alaimo (2007) they may have preferences for nonhuman noises over human voices and have difficulty discriminating speech from background noise. This can lead to deficits in receptive processing. Students with auditory processing issues may need extra time to compose answers to verbal questions and/or to be provided with written directions to accompany verbal ones.
The Vestibular System
- (Balance and Spatial Orientation)
The vestibular system provides information about motion, equilibrium, and spatial orientation to the brain. This information along with input from eyes and muscle and joints help maintain balance (Vestibular Disorders Association, 2013). Over stimulation of the vestibular system can lead to motion sickness, fear of heights, and poor depth perception. Children with ASD who require less vestibular input may avoid fast movements, hold head stiffly, and look up while bending down to pick things up. Other individuals may crave more vestibular stimulation. They enjoy fast movements such as swinging and never get dizzy.
The Gustatory System
- (Taste and the Texture, Temperature and other Sensory Impressions of Food)
The gustatory system is taste and the receptors on the tongue. It involves not only the sense of taste; sweet, salty, sour and bitter, but also textures of foods. Students with ASD who have gustatory sensitivities may have an aversion to strong tasting foods and need bland and simple familiar textures. If they have an under responsive gustatory system they may crave spicy or strong tasting foods. Some students may also have a compulsive need to chew inedible items (pica) to satisfy positive gustatory feedback.
- (Smell; Airborne Substances and Pheromones)
The olfactory system or sense of smell is most directly connected with arousal systems in the brain. Biologically, some individuals are very sensitive to odors while others are not (Heflin and Alaimo 2007). Smells can evoke powerful memories for individuals. Many students with ASD appear to have low thresholds for odors (Heflin and Alaimo 2007). They may need to be in classrooms that are cleaned with unscented chemicals and seated away from garbage cans. It is also helpful if the teacher does not wear perfume/cologne or use strong smelling lotions. The lunchroom can also be over stimulating, and a separate classroom may need to be available for the student to eat lunch. Some students may respond positively to strong smells. They need lotions, scented markers, strong air fresheners, or other olfactory stimulants throughout the day.
The Visual System
- (Perception of Light and Visual Objects, Assessing Distances; Circadian Rhythms)
Vision is not only the physical act of seeing something, but also the manner in which something is perceived and identified by the brain. It includes spatial awareness and depth perception as well as identifying an object in the line of sight. Students with ASD may be overly sensitive to stimuli such as color and light. They may not be able to process what they see if it is overcrowded. For example, a bulletin board or classroom may display so much information that the student cannot discern important information from decoration. The same can be true for a test that is not presented with as few words as possible. Heflin and Alaimo (2007) also point out that unusual use of the visual system in terms of eye gaze is a commonly reported feature in ASD. Individuals with ASD tend to focus their gaze on physical features of a setting and not the social features.
Below are short panoramic videos of two structurally identical classrooms. They are both located in the same high school in the same hallway. Both teachers who use these classrooms are sophomore English teachers. Which classroom do you think would be more accommodating to a student who has visual stimulation challenges due to autism?
The answer is different for every student. Some students with ASD who have visual challenges may be easily over-stimulated by what they see in their visual field. Other students with ASD who have visual challenges may be under-stimulated what they see in their vidual field. For students who are over-stimulated, Classroom #1 would be problematic, because it has articles all over the walls. This classroom would clutter a student's mind and they would have a difficult time focusing. Classroom #2 has very little on the walls. This would be an appropriate setting for a student who is over-stimulated by their visual system because there is very little on the walls. As for a student who is under-stimulated visually, Classroom #1 may be more beneficial, because teacher is using the walls as a teaching tool, using visual stimulation to teach vocabulary and other concepts.