Sensory integration in children with autism spectrum disorder

Sensory processing disorder in children with autism spectrum disorder

SENSORY INTEGRATION

The term sensory integration can be understood in several meanings: as a theory, as an ability of the nervous system and, last but not least, as a therapeutic approach developed in the 1970s by occupational therapist A. Jean Ayres.

Ayres' work was based on clinical observations of children with learning disabilities. Many of them showed difficulties in the field of sensory, perception and motor skills. Based on the assumption that "learning is a function of the brain (and) learning disabilities... are the result of a deviation of the nervous system", she developed the theory of sensory integration (SI). This theory, based on knowledge from neuroscience, biology, psychology and pedagogy, assumes that children with learning disabilities have problems processing and integrating sensory information, which affects their behavior and learning (Schaaf, Miller, 2005).

Sensory integration theory explains the relationship between the processing of sensory stimuli and an individual's behavior.

Smith Myles et al. (2007) list five prerequisites for sensory integration. The first basic assumption is the plasticity of the central nervous system - that is, it is possible to change and modify its structure. The second assumption states that the process of sensory integration happens in a developmental sequence. The third assumption is based on the fact that the brain functions as a whole, but the individual sensory systems are organized in a hierarchy. Sensory stimuli are organized and integrated in lower (subcortical) areas. Higher areas are more complex and processes such as speech, learning or behavior take place in them. The fourth assumption is the claim that adaptive behavior is the result of sensory integration and, conversely, that eliciting an adaptive response facilitates sensory integration. The final, fifth, assumption is that the capacity for sensory integration is developed unconsciously through sensorimotor activities.

Sensory integration is the process of organizing sensory inputs that happens without conscious control so that the brain creates appropriate responses of the body and sensory integration allows sorting, organizing and composing sensory inputs into a single whole. It enables the individual to act and react to situations in an appropriate way - it enables the creation of so-called adaptive response. It is the basis for academic learning and social behavior (Ayres, 2005).

It is the ability to receive, understand and organize sensory information from the external environment or one's own body and to combine individual sensory inputs into a whole. If these brain functions are complete and balanced, learning is easy and "good" behavior is a natural consequence (Emmons, Andersson, 2005).

The process of sensory integration is efficient for most individuals. This means that we receive and process information and respond appropriately to it. We register, orient ourselves, interpret and react in a way that is appropriate for the given situation. The brain's regulatory capacity, or modulation of sensory messages, supports this performance by integrating information. The result is then behavior or action that is consistent with the individual's intention. The quality of the behavior is a feedback to the central nervous system about whether the information processing has been done correctly (Smith Myles et al., 2005).

Sensory integration develops already before birth, when the fetal brain perceives the movements of the mother's body (Ayres, 2005).

DISORDERS OF SENSORY PROCESSING

Individuals whose sensory processing is not correct have difficulties in one or more areas of sensory perception or at some point in the integration process (Smith Myles et al., 2005). In these individuals, the brain then incorrectly or insufficiently processes and organizes sensory inputs, which manifests itself in difficulties in various areas such as learning, motor skills, and behavior.

It is not brain damage or absence of function, but the child's brain works in a different way (Ayres, 2005).

In the literature we can find different terms for this kind of problems. Ayres (2005) talks about sensory integrative dysfunction, Hilton (2011); Koomar et al. (2007); Kranowitz (2005) use the term sensory processing disorders. However, both terms refer to the same thing.

Sensory integration disorder can manifest itself with symptoms in different areas. Bogdashina (2003) defines the following symptoms:

• increased/decreased level of reactions to stimuli,
• tendency to get distracted,
• emotional and social problems,
• unusually high or low activity level,
• motor clumsiness,
• impulsiveness, lack of self-control,
• difficulty moving from one situation to another,
• weak self-concept,
• delay in speech and motor skills,
• difficulties in the academic field.

Sensory processing disorders were divided by Schaaf and Miller (2005) into the following categories:

Sensory modulation disorders are characterized by the child's disproportionate reaction to incoming stimuli. His nervous system is not able to find the so-called middle limit, he is not able to adapt his reaction to the intensity, frequency and duration of the stimulus. It manifests as over-sensitivity, under-sensitivity to stimuli or seeking stimuli (Sher, 2009). We will pay more attention to sensory modulation disorders in the next text, as these are often mentioned in connection with autism spectrum disorders.

Disorders of sensory discrimination are manifested by difficulties in interpreting the qualities of individual stimuli. The child has difficulty distinguishing similarities and differences in stimuli. The ability to discriminate is a basic prerequisite for the formation of a body schema, because the correct interpretation of sensory stimuli is essential for planning movements. Sensory discrimination disorders may not only involve sight or hearing. They can also affect other sensory systems. They then manifest as problems distinguishing textures or smells. Children with this disorder may also have difficulty recognizing objects by touch without visual control (Emmons, Andersson, 2005; Hilton, 2011; Sher, 2009).

Sensory-based motor disorders include postural disorder and dyspraxia. A postural disorder is characterized by inadequate muscle tension, hypotonia, hypertonia, inadequate control of movements, or inadequate muscle coordination when the individual wants to achieve movement against resistance. Such children appear weak, tire quickly, and do not consistently use the dominant hand or midline of the body. Dyspraxia manifests itself as a reduced ability to conceive, plan, sequence and execute a sequence of movements. Children with dyspraxia are unsure of where their body is in space and have difficulty judging the distance to objects or people, as well as regulating their strength when performing movements. In motor disorders, proprioceptive and vestibular stimuli are not properly processed (Ayres, 2005; Hilton, 2011; Sher, 2009).

As Kranowitz (2005) states, sensory processing disorders can occur alone, but are also seen in individuals with ADHD, learning disabilities, autism spectrum disorder, or cerebral palsy.

In particular, children with autism spectrum disorder show peculiarities in the processing of sensory inputs and have difficulty responding to tasks and environmental demands (Hilton, 2011).

Sensory processing disorders, according to various studies reported by Baranek (2002), occur in 42-88% of the population of children with autism spectrum disorder. Also, Hilton (2011), based on the analysis of various studies, points to a 69-100% occurrence of sensory modulation disorders in this group of children.

Ayres (2005) describes problems in processing stimuli in children with autism in three areas. He is the first to mention the problem in the registration of the initiative. The child is not able to select the necessary stimuli, ignores them or reacts to them intensively. He sees the second problem in modulation (mainly of vestibular and tactile stimuli). According to her, the third problem lies in the execution of a motor reaction. The child feels insecure and has little or no interest in doing various activities.

Children with autism spectrum disorder often show modulation disorders, that is, they are unable to adapt the intensity of their reaction to the intensity of the stimulus. Modulation disorders manifest as:

• Hypersensitivity is an overly intense reaction or high sensitivity to stimuli. The child reacts hypersensitively and even impulsively even to ordinary stimuli. He reacts by crying, screaming or running away. It mainly affects tactile and auditory perception, but it can also appear in other senses. The result of hypersensitivity is then defensiveness - avoidance of given stimuli.
• Hyposensitivity, on the other hand, is manifested by a high degree of tolerance to stimuli. The child reacts late or not at all, or the stimulus must have a higher intensity than usual. It can manifest with any sensory system.
• Sensory deprivation – search for stimuli. In this case, the child actively searches for the stimuli he needs. Often this distress manifests itself as a fascination with certain stimuli or as repetitive and stereotyped behavior (Bogdashina, 2003; Hilton, 2011; Smith Myles et al., 2005).

In the following text, we will describe in more detail the manifestations of sensory processing disorders in individual areas of sensory perception.

The vestibular apparatus provides information about the position and movement of the head and body in space. Disorders in the processing of vestibular stimuli are manifested in children with autism spectrum disorders as fear and uncertainty about movements, especially if the feet do not touch the ground, they have difficulty changing the direction and speed of movement - hypersensitivity. Hyposensitivity in this case may include the inability to sit still and the need to move. Some children seek vestibular stimuli, which manifests as stereotypic behavior. This is, for example, rocking or spinning (Hilton, 2011; Koomar et al., 2007; Smith Myles et al., 2005).

Proprioception makes it possible to perform movements and keep balance, it helps to create a body schema. Children with autism spectrum disorder who cannot process these stimuli are insecure, clumsy, have problems planning movements and weak muscle tone. If they are hypersensitive to proprioceptive stimuli, they may be passive and fear movement or dislike passive movement. However, many (hyposensitive) children look for these stimuli, for example, by bumping into objects, banging or stomping. They often seek pressure, as they accept deep sensations much better than surface-tactile ones (Ayres, 2005; Koomar et al. 2007; Smith Myles et al., 2005).

Tactile perception – problems in the field of tactile perception were already described in his work by Hans Asperger, who noticed disproportionate reactions to tactile stimuli. Children who are hypersensitive may react emotionally or aggressively to touch or objects with a certain texture. Hypersensitivity to tactile stimuli then leads to tactile defensiveness. This means that the child will defend and avoid the stimuli. The child may have difficulty standing in a line or approaching someone very close - fear of touch. Tactile hypersensitivity will also affect the functioning of the child at school, in the home environment and also his possibilities of involvement in play activities. Conversely, hyposensitive children will not register stimuli until they are quite intense. They can react slowly to them, even seek them out (touching objects, people). Hyposensitivity is also associated with higher pain tolerance, which in some children is also related to self-injurious behavior. Hyposensitive children can use their mouths to explore objects (Hilton, 2011; Koomar, et al. 2007; Smith Myles et al., 2005).

Auditory perception is atypical in most children with autism spectrum disorder (Hilton, 2011; Lord - McGee, 2001). Children are often hypersensitive to sounds that people react to in a normal way and do not find them unpleasant. They can be startled by loud noises and voices as well as sudden noises. Hyposensitivity also appears, when children do not respond to sounds because they are unable to distinguish them from the environment or do not respond even if there are no other sounds in the background. These difficulties often lead to inappropriate behavior if the child does not understand or his hearing is overloaded (Ayres, 2005; Koomar et al., 2007; Smith Myles et al., 2005).

Visual perception is a strong point of children with autism spectrum disorder. Nevertheless, they have disorders in the processing of visual information. They manifest themselves in the form of an overly sensitive reaction to some light sources (fluorescent light, luminous objects...). These children may prefer darker spaces or avoid direct light. Hyposensitivity manifests itself as intense staring at objects or people. Some seek intense, flashing or sunlight. Processing disorders are also manifested in other areas, such as the ability to orientate in space or when writing - spatial distribution of writing, copying from the blackboard (Hilton, 2011; Koomar et al., 2007; Smith Myles et al., 2005).

Smell and taste perception – its specifics are mainly in the repertoire of foods that children are willing to accept. They only consume food of a certain taste or consistency and, conversely, will avoid other foods. In the area of ​​olfactory perception, an oversensitivity to some odors that are commonly found in the environment can be manifested (Hilton, 2011; Smith Myles et al., 2005).

In children with autism spectrum disorders, sensory processing disorders can also affect the development of the ability to plan movements, create a body schema, and negatively affect the child's willingness to engage in various activities or try something new and different (Ayres, 2005).

SENSORY INTEGRATION THERAPY (SENSORY INTEGRATION THERAPY – SIT)

The basic idea of therapy is to provide and control sensory inputs, especially inputs for the tactile, proprioceptive and vestibular system (but also other senses), in such a way that the child will spontaneously form adaptive responses and integrate incoming sensory information (Ayres, 2005).

It is believed that thanks to these experiences, the nervous system better modulates, organizes and integrates information from the environment, thus creating a basis for the creation of other adaptive responses and further learning (Lord, McGee, 2001). Everything happens through play and involving the child in meaningful activities.

The goal of SIT is to support the ability of the central nervous system to process sensory input in a more normal way (Bogdashina, 2003). SIT is important if the child has control over his own activity and the therapist subtly controls the environment (Ayres, 2005). By balancing freedom and structure, the therapist helps the child develop organization and inner direction (Koomar et al., 2007). Children with more severe disorders, especially children with autism spectrum disorders, require more external guidance and structure. Sometimes fear or other emotions may appear that are not consistent with the child's adequate self-control. The therapist must help the child manage these negative emotions and reactions while the child is exposed to the stimuli he needs and gradually develops adaptive responses (Ayres, 2005).

As Ayres (2005) further writes, with SIT it is not so much about teaching the child a given activity or a specific motor skill, but the intention of the therapist is to help the child function better physically, emotionally and academically. The therapist helps the child to be better prepared to acquire motor skills, academic abilities, or appropriate behaviors. Motor activity is suitable precisely because it provides sensory inputs that better help the child to organize his own learning.

In SIT for children with autism spectrum disorder, we try to convey stimuli for depth perception (proprioception), especially for those children who are hypersensitive to touch. Activities such as pushing, pulling or jumping can have a calming effect on the child. Activities can also include vibrations that will stimulate receptors in individual parts of the body. Appropriate attention is also paid to the vestibular apparatus through activities such as swinging, spinning, jumping - these activities are sought after by many children with autism spectrum disorders.

Already Ayres (1979) and Delacato (1974) (In Bogdashina, 2003) hypothesized that many children with autism could be helped by gentle stimulation of the five senses or the vestibular, proprioceptive and tactile systems. These three sensory systems were considered by Ayres to be the most important, and the focus of the intervention was to stimulate these systems. Nowadays, all senses are considered in sensory integration therapy. But some therapists still follow Ayres and focus mainly on the proprioceptive, vestibular and tactile systems.

In order to qualify as a sensory integration method/therapy, an intervention must meet the following requirements:

• provide opportunities to engage more than one sensory system (proprioceptive, vestibular, tactile),
• provide activities that challenge the child, but are neither too difficult nor too easy,
• cooperate with the child in choosing activities,
• support and accompany the child in organizing his own behavior, help in choosing and planning his own behavior,
• ensure that the therapeutic situation is beneficial for achieving and maintaining the child's optimal level of activity/reactions,
• maximize the child's success,
• ensure the safety of the child,
• arrange the room and the tools in it in such a way that the child is motivated to choose and participate in the activity,
• create an atmosphere of trust and emotional security (Hilton, 2011).

Somewhat different principles for sensory integration are presented by Bogdashina (2003):

• child orientation,
• active participation of the child,
• individualized care,
• targeted activities,
• the need for an adaptive response (adequate reaction to a stimulus),
• dominance of activities aimed at the proprioceptive, vestibular and tactile system,
• setting a goal - improving the processing and organization of perceptions,
• execution of SI by a trained expert.

SIT requires an experienced and trained therapist/expert as well as a modified environment in which it will be implemented. SIT takes place in an environment where the child has enough opportunities for his own activity and play. In this environment, there are various types of swings, hammocks or bags. In addition, various obstacles, inclined planes, hollow cylinders, boards on wheels, objects with different textures and others can be found in it.

If we talk about a trained professional, Ayres (2005) and Bogdashina (2003) mainly mean an occupational therapist or a physiotherapist who has a certificate to perform SIT. Abroad, SIT is mainly the domain of the mentioned groups of experts.

In some countries, SIT is also performed by psychologists, special or remedial educators who have obtained a certificate in this field.

Several approaches are used in sensory integration therapy.

1. Multisensory integration – this is a strategy in which the senses (sight, hearing, smell, taste, touch, proprioceptive and vestibular system) are used in an integrated way. This means that several senses are involved at once.
2. Desensitization is a way to increase tolerance to stimuli, eye contact, reduce stereotyped, self-injurious or aggressive behavior in some children. In this case, the activities are designed and targeted in such a way as to gradually increase the threshold of sensitivity and achieve an adequate response to stimuli. Children are not forced into activities, but are exposed to stimuli easily and gradually in the form of games and pleasant activities (Bogdashina, 2003).

Another approach that can still fall under sensory integration is the so-called ,,sensory diet". The environment is organized in such a way that it offers activities and stimuli that fulfill the sensory needs of the child. Each sensory diet is planned according to the individual needs of the child. It is dominated by stimulation of the tactile, vestibular and proprioceptive systems (Bogdashina, 2003; Lord - McGee, 2001).

However, there are not enough research studies examining the effectiveness of sensory integration therapy for individuals with autism spectrum disorder, but in recent years these individuals have become the subject of research interest. Some authors such as Hyatt et al. (2009) are skeptical of this form of intervention on the basis that some studies have not demonstrated its effectiveness. Other studies are criticized for methodological shortcomings.

On the other hand, some studies, which Baranek (2002) or Hilton (2011) refer to in their works, for example, demonstrate the positive impact of sensory integration therapy in persons with autism spectrum disorder. Positive changes were observed mainly in the area of social interaction, deliberate play or reduced sensitivity to individual stimuli.

In conclusion, it should be emphasized that sensory integration therapy cannot be considered a substitute for other approaches, but can be used as a complementary intervention (Baranek, 2002).

Author: PaedDr. Jana Hrčová, Ph.D. The author works in the civic association 3lobit, o.z. in the position of professional guarantor of educational activities. www.3lobit.sk

Used literature:

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