Sensory Sensitivities

Although sensory processing differences are listed in DSM-5 as a subitem of the repetitive behavior area, they play such a clear and important role in daily life that they deserve to be covered as a separate chapter in this book. In the great majority of children with autism, there is a response pattern different from typical development in one or more sensory systems.

Sensory Over-Responsiveness (Hypersensitivity)

Some children respond in an overly intense and distressing way to stimuli that are typically considered harmless (certain sounds, textures, lights, smells). The sound of a vacuum cleaner, a label touching their skin, the flicker of a fluorescent light, or the general noise of a crowded shopping mall can lead to real overwhelm, even a panic response, for these children. These reactions aren't "overreacting" or "being spoiled"; they reflect the fact that the child's nervous system truly experiences these stimuli more intensely.

Sensory Under-Responsiveness (Hyposensitivity)

The opposite can also happen: some children respond far less than expected to certain stimuli; a high threshold for pain, not noticing differences in temperature, and not responding to their name being called (even though there is no hearing loss) fall into this category. These children may be in search of strong sensory input: they may seek spinning, jumping, being held tightly, or strong tastes or smells.

Sensory Seeking Behaviors

Some children actively seek out certain sensory experiences: waving their fingers in front of their eyes (seeking visual stimulation), smelling objects, staring at spinning objects for a long time, or wanting to be held tightly to feel the weight of their body. These behaviors should be understood as part of the child's effort to regulate their own sensory system.

Caution / When to Seek Advice

A high threshold for pain can lead some children to notice a serious injury or illness late. Parents should learn to recognize the ways their children express pain (indirect signs such as changes in behavior, loss of appetite, or disrupted sleep) and should not neglect a medical evaluation when there are unexplained changes in behavior.

Assessing the Sensory Profile

Every child's sensory profile is unique; a child may be over-responsive to sound while under-responsive to touch, and in another child the reverse may be seen. Occupational therapists systematically assess the sensory profile using standard scales (for example, the Sensory Profile-2), and this assessment guides the sensory setup of home, school, and therapy environments (see Chapters 23 and 32).