Some of the most common problems autistic individuals experience are their hyper- or hypo-sensitivities to sensory stimuli. Their senses seem to be too acute (hypersensitivity) or not working at all (hyposensitivity).
Hypervision means that their vision is too acute. For example, they notice the tiniest pieces of fluff on the carpet, complain about ‘moths (air particles) flying’, dislike bright lights, look down most of the time and may be frightened by sharp flashes of light. Under fluorescent lights such children can see a 60-cycle flickering: the whole room pulsates on and off.
Individuals with hyperhearing are generally very light sleepers, are frightened by sudden unpredictable sounds (for instance, telephone ringing, baby crying); they dislike thunderstorm, crowds and are terrified by haircut. They often cover their ears when the noise is painful for them, though others in the same room may be unaware of any disturbing sounds at all. Sometimes hyperauditory children make repetitive noises to block out other disturbing sounds.
Children with olfactory hypersensitivities cannot tolerate how people or objects smell, though their carers can be unaware of any smell at all. They run from smells, move away from people and insist on wearing the same clothes all the time. For some, the smell or taste of any food is too strong, and they reject it no matter how hungry they are. They are usually poor eaters, gag/vomit easily and eat only certain foods.
Some individuals with ASDs are hypertactile. They pull away when people try to hug them, because they fear being touched. Because of their hypertactility, even the slightest touch can send them into a panic attack. Parents often report that washing their child’s hair or cutting nails turns into an ordeal demanding several people to complete it. Many individuals refuse to wear certain clothes, as they cannot tolerate the texture on their skin. Some children with hypertactility overreact to heat/cold, avoid wearing shoes, avoid getting ‘messy’ and dislike food of certain texture.
Children with vestibular hypersensitivity experience difficulty changing directions and walking or crawling on uneven or unstable surfaces. They are poor at sports. They feel disoriented after spinning, jumping or running and often express fear and anxiety of having their feet leave the ground.
Individuals with proprioceptive hypersensitivity hold their bodies in odd positions, and might have difficulty manipulating small objects.
Sometimes the senses of autistic children are in ‘hypo’, so that they do not really see, hear or feel anything. To stimulate their senses they might wave their hands around or rock forth and back or make strange noises.
Children with hypovision may experience trouble figuring out where objects are, as they see just outlines, then they may walk around objects running their hand around the edges so they can recognise what it is. These individuals are attracted to lights, they may stare at the sun or a bright light bulb. They are fascinated with reflections and bright coloured objects. Having entered an unfamiliar room they have to walk around it touching everything before they settle down. Often they sit for hours moving fingers or objects in front of the eyes.
Children with hypohearing may ‘seek sounds’ (leaning their ear against electric equipment or enjoying crowds, sirens and so on). They like kitchens and bathrooms – the ‘noisiest’ places in the house. They often create sounds themselves to stimulate their hearing – banging doors, tapping things, tearing or crumpling paper in the hand, making loud rhythmic sounds.
Individuals with hypotaste/hyposmell chew and smell everything they can get (e.g. grass, play dough). They mouth and licks objects, play with faeces, eat mixed food (for instance, sweet and sour) and regurgitate.
Those with hypotactility seem not to feel pain or temperature. They may not notice a wound caused by a sharp object or they seem unaware of a broken bone. They are prone to self-injuries and may bite their hand or bang their head against the wall, just to feel they are alive. They like pressure, tight clothes, often crawl under heavy objects. They hug tightly and enjoy rough and tumble play.
Children with vestibular hyposensitivity enjoy and seek all sorts of movement and can spin or swing for a long time without being dizzy or nauseated. People with vestibular hyposensitivity often rock forth and back or move in circles while rocking their body.
Those with proprioceptive hyposensitivity have difficulty knowing where their bodies are in space and are often unaware of their own body sensations, for example, they do not feel hunger. Children with hypoproprioceptive system appear floppy, often lean against people, furniture and walls. They bump into objects and people, stumble frequently and have tendency to fall. They have a weak grasp and drop things.
Autistic children are often engaged in stereotyped activities. Very often these self-stimulatory behaviours – such as
- Flapping their hands
- Tapping things
- Watching things spin
(which are often defined by non-autistic people as ‘bizarre/abnormal behaviours’), – can be viewed as involuntary strategies the child has acquired to cope with ‘unwelcome (and often painful) stimulation’ (in the case of hypersensitivity) or to arouse the nervous system and get sensory stimulation from the outside (in the case of hyposensitivity), and sometimes to provide themselves with internal pleasure. That is why, no matter how irritating and meaningless these behaviours may seem to us, it is unwise to stop them without learning the function they serve and introducing experiences with the same function.
Each of the senses should be assessed, and depending on the sensitivity, we can desensitize the child’s capability to tolerate the stimuli and/or to provide the aids to help him/her cope with ‘offensive’ stimuli (for example, tinted glasses, earplugs). Desensitization is aimed to increase sensory tolerance very gradually through pleasurable activities.