Sensory Processing Disorder
Sensory integration is a normal, neurological process which begins in utero and continues throughout life. It is the process by which our brains take in sensory information received from the body and our environment; and synthesize, organize and process that information in order to provide a goal directed response.
Sensory integration occurs in the following ways:
- Our central nervous system takes in the information
- The brain organizes the information and makes sense out of it
- This enables us to use it and act accordingly within our environment to achieve goal directed actions.
Sensory integration is important for:
- Social interaction
- Motor skill development
- Focusing and attending so learning can occur
Sensory Integration occurs through our senses which includes:
- Tactile – sense of touch
- Vestibular – sense of movement
- Proprioception – sense of position
- Auditory – sounds
- Visual – sight
- Taste – relating to input to the mouth
- Olfactory – smell
What is the significance of our senses?
Tactile System
The tactile system is our system of touch. Touch makes us feel safe and comfortable, and allows us to bond with those around us so we can develop socially and emotionally. There are two parts to the tactile system - one is the protective system and the other is the discriminative system.
The protective system lets us know when there is danger and causes a “flight, fright, fight” response. The discriminative system lets us know where we are being touched and what it is that is touching us.
When the tactile (discrimination) system is not working properly the following can occur:
- Difficulty with fine motor and self-care skills
- Difficulty articulating sounds
- Decreased visual perceptual skills
- Difficulty understanding basic concepts
- Exhibit the need to touch everything, have difficulty keeping hands to self
When the tactile (protective) system is not working properly the following can occur:
- Withdrawal from group situations
- Misperception of touch even when it is not threatening
- Overreaction to clothing or food textures or tastes
- Under-responsive to pain
- May not like to be held or cuddled
Vestibular System
The vestibular system encompasses our sense of movement and gravity. It lets us know which way is up, down, horizontal, and vertical. It also lets us know if we are moving, what direction we are moving, and how fast we are going. The vestibular system helps us to develop proper muscle tone, posture and bilateral coordination. This system is imperative to the functioning of the central nervous system and allows for other sensory inputs to be processed.
When the vestibular system is not working properly the following may occur:
- Difficulty making sense of visual information
- Difficulty with tasks that require two hands
- Difficulty with coordinated movements and development of gross motor skills
- Difficulty with sequencing and timing
- Extreme need for activity and movement/difficulty sitting still
- Lack the desire to engage in movement activities
- Fearful of movement experiences
- Inappropriate emotional responses
- Speech and language deficits
- Difficulty using words to reflect what they know
- Difficulty with nonverbal communication/body language
Proprioceptive System
The proprioceptive system consists of receptors located within our joints, tendons, ligaments, and connective tissue. Proprioception occurs when we stretch and tighten our muscles against the pull of gravity. Sensations that come through the proprioceptive system are closely linked to the tactile and vestibular systems. The proprioceptive system tells us where the body is in space, how our body parts relate to each other, how much and how quickly our muscles are stretching, and how much force our muscles are using.
Disruption in the proprioceptive system can result in:
- Decreased body awareness/bumping into objects
- Postural instability
- Difficulty with motor planning
- Difficulty grading movements — using too little or too much force
- Motor incoordination
Auditory System
The auditory system works together with the vestibular system as sound and movement are processed. The auditory system is the first sensory system to develop. The auditory system is not only responsible for hearing, but also for balance, coordination, flexibility, and equilibrium.
There are two components of the auditory system. The first is the defensive component which occurs when we are startled by a loud or unexpected sound. As we develop we learn to tune out sensations that are not threatening. The second component is the discriminative component. The discriminative component helps us determine the "what" and "where" of sounds.
Children who have difficulty with auditory processing may exhibit:
- Irrational fears of household appliances and noises
- Become distressed by sudden noises, thunder, sirens, or alarms
- Difficulty responding to their name being called
- Difficulty following directions, frequently asking “What did you say?”
- Difficulty attending in a noisy environment
- Difficulty differentiating between speech sounds, words, or phrases
Visual System
The visual system is responsible for what we see in our environment. The visual system also has two components which consist of the protective and discriminative components. These two systems work together, allowing us to see clearly. These systems also enable us to understand the objects we see, where they are, and how they feel (without touching them).
Children who have difficulty processing visual information may exhibit:
- Covering of the eyes when in direct sunlight
- Preference for watching spinning and/or shiny objects
- Difficulty following a moving object (i.e. catching a ball)
- Difficulty making eye contact
- Difficulty with discrimination (puzzles, letters, colors)
- Difficulty developing spatial and temporal concepts
- Poor eye-hand coordination
- Difficulty with coordination and balance
Sensory Processing Disorder
- Type I – Sensory Modulation Disorder (SMD) Over and under-responsivity to sensory stimuli and sensory seeking. Sensory modulation refers to the ability of the central nervous system to convey information about the intensity, frequency, duration, complexity, and novelty of sensory information. (Gravitational insecurity, sensory defensiveness, sensory registration)
- Child may be fearful, anxious, or hesitant about learning/exploring/social interactions
- Child may exhibit stubbornness, low frustration tolerance, inflexible
- Child may become self-absorbed in activity and have difficulty engaging/interacting
- Type II – Sensory Based Motor Disorder (SBMD) Motor actions are affected by inadequate processing of sensory information.
- Postural instability/insecurity
- Dyspraxia
- Coordination difficulties (clumsy, loss of balance)
- Sensory Discrimination Disorder (SDD) Discrimination of sensory information is inaccurate.
- Visual and auditory processing difficulties
