What do we know about sensory processing?

In everyday life, we are constantly inundated with sensory experiences. From loud beeping cars during the morning commute, to bright fluorescent lighting, to itchy jumpers, we can encounter a range of sensory experiences. For most people, these stimuli can come as a bit of an annoyance, which can be easily assuaged or forgotten. Yet for some individuals, sensory experiences can become overwhelming and cause disruptions to their daily functioning.Sensory processing refers to the way the nervous system receives messages from the senses and turns them into appropriate motor and behavioural responses. Research has shown that people’s responses to everyday sensory experiences are distributed along a bell curve, with most people responding moderately, and few people responding intensely. According to one study (Dunn, 2007), about 2-4% of people fall at the tail ends of this bell curve. As such, of 100 people, about 2 to 4 individuals will respond more intensely to sensory events. In a study of US preschool children, researchers conservatively estimated that 5.3% of children could be experiencing sensory processing difficulties (Ahn et al., 2004). At the moment, it is not a distinct diagnosis. However, sensory processing difficulties are found to co-occur in cases of autism spectrum disorders (ASD) and attention deficit hyperactivity disorders (ADHD).From as early as 1943 a pioneer researcher in autism, Leo Kanner, described children with autism’s sensory fascinations. These included joyous descriptions such as staring at light reflecting from mirrors, as well as heightened sensitivities that caused distress, for example covering ears to certain sounds. Similar findings have been reported in children with ADHD. One study found that infants who were more active, had less adaptability, and lower thresholds for stimuli were more likely to be diagnosed with ADHD at a later stage (Neu, 1997). It is thought that children with ADHD and ASD may not be receiving and processing sensory information properly. This can result in a difficulty to produce the appropriate responses at school or at home.There are three patterns of sensory processing most associated with children with ASD and ADHD. Hyposresponisvity refers to a lack of response. With this pattern, the individual has a high neurological threshold. As a result, stimuli need to be strong or intense in order to be processed appropriately. Children who exhibit this pattern of sensory processing may seem “in their own world” or may not respond when their name is called. Another pattern of sensory processing is hyperresponsiveness. This is an exaggerated behavioural response to stimuli. Hyperresponsive individuals have low neurological thresholds, which means they do not require a strong stimulus to process a sensory event. With this pattern, children may show an averse reaction to lights, cover their ears to sounds, or avoid touch of certain objects or fabrics. One other common pattern is sensory seeking. These individuals have a high neurological threshold, meaning they require a strong stimulus in order to process a sensory experience. However, they also have an active self-regulation strategy. This strategy causes individuals to create sensory experiences for themselves to meet this high threshold. Children with a sensory seeking pattern may be interested in touching a variety of different objects and textures to stimulate a sensory experience.