DISCOVERING YOUR CHILD'S SENSORY PROFILE

We rarely stop to think about how vitally important the five senses are in terms of giving us information about the world.  Without the ability to see, hear, touch, smell, and taste we would live in total isolation, unable not only to sense, but also to think, for we would lack any experience with which to develop ideas. 

In addition to these five common senses, there are the body senses:  the vestibular system, which is sensitive to gravity and movement and influence muscle tone, balance, and arousal; and the proprioceptive system, which provides awareness of movement and the position of the body in space and influences motor control and body schema.  These systems govern our ability to feel sure of our own body in space, to sense where “I” stops and the world begins.  These systems enable us to feel balanced and safe as we move, sit, and stand, to let other people get close, and to protect ourselves if we feel endangered.  In addition, our affects or emotions also function as a way to sense what is going on around us.  A stimulus may be hard and scary at the same time. 

Within each of these senses, people can be under- or overreactive depending on their sensory threshold (the point at which the combined sensory input activates the central nervous system and we see a response).  People who are underreactive don’t respond to small or even moderate amounts of stimulation in the area of their sensitivity; people who are overreactive find small or moderate amounts of stimulation overloading or irritating.  People who are underresponsive to sound, for instance, may fail to respond to ordinary speech.  They need loud, often highly rhythmic sounds to capture their attention.  People who are extremely underreactive to sound fail to respond to noise at all.  People who are overreactive, on the other hand, may find speech or television every bit as irritating as fingernails on a chalkboard.  Vacuum cleaners and kitchen utensils may be especially bothersome.  To these people, only the quietest, gentlest sounds are tolerable.

People who are underreactive to touch may barely perceive common tactile stimuli, such as a hug or the pressure of a chair beneath one’s legs.  They may be insensitive to pain.  People who are overreactive to tactile stimulation may feel pained at the slightest touch.  A gentle pat or the feel of certain fabrics against their skin may register as severe irritation.  Children who are sensitive to visual stimuli may overreact to lights and color, or may be so overloaded by color, shape, and detail that they fail to see the big picture.  Other children may miss the details and see only the forest but not the trees.  Misperceiving the world in any of these ways affects all a child’s interactions.

Children will often compensate for their under- or overreactivity.  A child who is overreactive to certain stimuli may try to avoid those sensations, whereas a child who is underreactive may seek them out.  A child who is hypersensitive to sound may retreat to a quiet place so as not to be overwhelmed.  A child who is underreactive to touch, or whose kinesthetic or proprioceptive senses are underreactive and who therefore does not register where he is in space, may need to run or bounce or swing endlessly to get the sensory input to inform him.  Alternatively, if an underreactive child also has low muscle tone, she may become self-absorbed and more and more impervious to the world around her.

What makes under- and overreactivity even more problematic is that sensory input is not discrete.  Information comes to us from many sources at a time—from our eyes and our ears and from where our bodies are in space.  It accumulates with time; at any moment it is being combined with the sensory data we took in seconds before.  Thus a child’s ability to process such data is context-dependent.  For example, a child might respond pleasurably to a song sung by a parent in a quiet room while being held, but might not respond at all to the same song sung in a noisy, active classroom.

To make the sensory puzzle even more challenging, children with severe impairments are usually underreactive, overreactive, or a combination in several areas.  A child may be overreactive to sound and to touch, but underreactive to movement.  This child may shy away from noises and physical contact, but crave the motion of spinning and swinging.  Another child may be overreactive to sight but underreactive to sound.  This child may be frightened of oncoming traffic, but fail to respond when his parent calls out a warning.  To add further complexity, a child’s reactivity may change from one moment to the next.  Stress, fatigue, or high emotion can cause a child’s reactivity pattern to change.

Sometimes reactivity varies within a sensory area.  For example, a child may be oversensitive to sounds in a certain frequency range (e.g., vacuum cleaners and motor sounds) and underreactive to those in another (e.g., an ordinary human voice).  Typically, though, children evidence a pattern, for example, of oversensitivity.

It’s easy to see how people with sensory impairments can miss out on a lot of information from the world.  For instance, we depend on hearing not only for big pieces of information, such as a person’s words or the sound of a car hurtling past, but also for details, such as nuances in a person’s voice that can mean the difference between genuine concern and sarcasm or between patience and impatience.  The ability to distinguish all the gradations of sound enables us fully to take in and understand the world.  The same is true for each of the other senses.  Vision not only helps us discern one individual from another, but also helps us detect the nuances of facial expression that indicate when a person is genuinely interested or merely tolerant, or when a smile is warm and loving versus mechanical.  Vision enables us to determine when objects in our space are arranged in one configuration or another.  The sense of touch enables us to discern pain from pleasure, and the difference between a playful pat and an accidental bump of equal pressure.  Most important, it provides a part of our boundary with the outside world.

Children whose senses function fully read and interpret billions of tiny sensory cues as they master the skills of human interaction.  But children with sensory impairments may miss or misperceive these critical bits of information as they learn to interact with the world.  Learning to pay attention, learning to engage with others, and learning to communicate may all be affected.

Discovering your Child's Sensory Profile

• Entering your child's world involves more than simply intuiting what gives your child pleasure; it's a systematic process. You must first learn how your child's nervous system works, by understanding his or her unique style of hearing, seeing, touching, smelling, and moving. To help your child feel comfortable in the world you must first carefully observe which sensations help your child become calm and regulated, which ones overwhelm him or her, and which don't pull him or her in enough. - Source: Greenspan & Wieder (2006). Engaging Autism. Chapter 6.
• You might also want to read a nice blog ("A little bit Autistic") that shows how a mother discusses her son's sensory profile.