By Abha Ranjan Khanna
The brain is truly the most amazing computer ever devised! It receives countless pieces of information from internal and external stimuli at every second. The ability to classify, organise, store, recall and utilise this information provides the basis for learning. Sensory integration is therefore described as “the organisation of sensation for use”.
Sensory processing is the organisation of sensory input from the body and the environment for use. Praxis is the ability to plan and sequence unfamiliar actions, like learning a new dance form. Motor performance is the actual execution of the gross and fine motor coordination.
The brain directs and processes the traffic flow of information and through our five primary senses we learn and develop through interaction with our environment.
Sensory processing issues are difficulties with organising and responding to information that comes in through the senses. Children with these issues may be oversensitive to sensory input, under sensitive, or both.
Kids who are sensory avoiding may react to a wide range of triggers. These can include loud sounds, uncomfortable clothing, crowded spaces, or certain food smells or textures, among others. Whatever the trigger, the reaction can sometimes be extreme. It is a good idea to pay attention to these and not just believe that the child is just overly sensitive and needs to toughen up.
Sensory information isn’t limited to the traditional five senses: sight, smell, taste, touch and sound. Interoception is a lesser-known sense that helps you understand and feel what’s going on in your body – like a racing heart and the sensation of hunger. Kids who have trouble with interoception may have a harder time with toilet training or have an unexpected threshold for pain.
Two other senses, body awareness (proprioception) and spatial orientation (the vestibular sense), can also affect kids with sensory issues.
Sensations may be thought of as “food for the brain”, and when they flow in an integrated manner, the brain can use those sensations to form perceptions, behaviours and learning. Without integration, the sensations cannot be ‘digested’ and used.
The human body was designed to move, and it is our early experiences that lay the foundation of what follows. Every movement is a sensory motor event, and movement reinforces our learning capacity; to truly store something mentally, some type of movement activity is required, either speaking out loud, writing or other physical action such as gesticulation. By putting it into ‘muscular memory’ it is more likely to be remembered than something simply thought about and not ‘acted out’.
Constant sensory input and processing are required throughout life as well as in the early stages to maintain active development of neural networks within the brain. These networks are constantly being structured by dendrite formation and pruning. Every new motor activity performed generates a burst of dendritic formation creating new connections within the brain. If these new connections are not reinforced, they are literally reabsorbed by the cell body.
For example, a two-year-old child with an eye infection has to have an eye patch over it for two weeks. During that time the synaptic connections from the right eye to the visual cortex will be reabsorbed by the cell body and right field vision will be permanently impaired. The old adage “use it or lose it” is true!
Of particular interest is the sensory motor stage of development (six months onwards) when children start to roll, crawl and walk. As they respond to auditory (mom calling the child’s name) and visual (toys placed slightly out of the child’s reach) stimuli they develop motor skills and actively learn by exploring the environment. It takes seven to eight years of play and movement for a child to develop the sensory motor intelligence that can serve as the foundation for intellectual, social, and personal development.
Without early intervention, children with sensory integration difficulties seldom “grow out of it”.
(The writer is an occupational therapist.)