What is Occupational Therapy?

Sensory integration (SI) is the neurological process that organises sensation from one's own body and the environment. It enables everyday life (Allen and Smith 2011). For most people, sensory integration develops in the course of ordinary childhood activities.

For some people, sensory integration does not develop as efficiently as it should. This is known as sensory processing disorder (SPD) or dysfunction in sensory integration (DSI). DSI and SPD are both ways to describe the difficulty some people's nervous systems have with taking in, integrating and making use of sensory information. This changes how the person then responds to changes in their own body, the environment and how they interact with it and others around them.

Sensory integration difficulties can influence self-regulation, movement, learning and interaction with others (Allen and Smith 2011). SPD can interfere with skills that support performance, such as engagement and attention, as well as skills that enable the learning of new motor skills (Cosby, 2010; Jasmin, 2009).

Sensory integration difficulties can occur across the lifespan. They can been seen in isolation or, more frequently, in combination with other diagnoses - including Autistic Spectrum Disorders, Attention Deficit, Learning Disabilities, Developmental Coordination Disorder and Regulatory Disorder.

(Sensory Integration Network, 2016)

Sensory modulation refers specifically to the brain’s ability to respond appropriately to the sensory environment and to remain at the appropriate level of arousal or alertness. There are actually three primary types of Sensory Modulation difficulties:

• Over-responsivity: An exaggerated response of the nervous system to sensory input. For example, people who get motion sick easily are over-responding to vestibular input (the sensation of movement). The nervous system goes into fight-or-flight mode even when no real danger exists.
• Under-responsivity: A lack of response, or insufficient response to the sensory environment. Sometimes these people appear to be daydreaming or unfocused on what is happening around them. They may also be uncoordinated and have difficulty with motor skills development.
• Sensory seeking: The nervous system of the sensory-seeker needs intense input in order for the sensation to be registered properly in the brain. Therefore the sensory-seeker craves intense sensations constantly.

(Sensationalbrain.com)

Ayres's model of the sensory integrative process shows how interaction between the auditory, vestibular, proprioceptive, tactile and visual systems provide integrated information that contributes to increasingly complex behaviours. Postural control, balance, muscle tone, gravitational security are achieved through the development of the vestibular and proprioceptive systems. These systems interact with the tactile system which provides an important foundation for adequate body awareness, coordination of two sides of the body and praxis. These sensory motor functions form the foundation for eye hand coordination, perceptual skills and engagement in purposeful activity. Together with the auditory system these sensory systems contribute to speech and language development which forms an important foundation for behaviours needed for learning.