Integration is a substep of perceptual processing and gives people a meaningful picture of their environment. Sensory integration involves different sensory systems and different sensory qualities. In integration disorders, integration is impaired because of a lack of neuronal linkage.
What is integration?
Integration is a substep of perceptual processing and gives humans a meaningful picture of their environment. Using his senses, a person perceives the world. An external stimulus hits special sensory cells, which transmit the information to the brain via the spinal cord. What a person recognizes and perceives from all the stimuli in the environment is not decided in the sensory processes, but only with the recognition processes in the brain. The recognition of a stimulus is one of the last elements in the chain of perception. On the way between sensation and recognition there are many perceptual substeps. One of them is sensory integration. This medical term refers to the interaction of different sensory systems and sensory qualities. Only through this co-ordinated integration is the human being able to recognize and interpret percepts as a situation. For example, the sensory integration of vestibular stimuli and deep sensory stimuli provides information about one’s position in space and influences balance. The field of proprioception relies particularly heavily on sensory integration, but the integrative substep of perception applies to all sensory systems to varying degrees. The goal of all sensory integration is appropriate engagement with the environment, made possible by orderly processing pathways of the individual sensory systems. Without sensory integration, humans are unable to take purposeful or planned actions in response to environmental stimuli. It is the integration of individual sensory perceptions that creates the picture of a situation and thus the possibility of situational response.
Function and task
Integration creates an order of all momentarily acting sensory impressions and thus corresponds to the utilization of stimuli as a situational overall picture. Thanks to proprioception, for example, information about one’s own body state and posture or movement constantly reaches the human brain. This interoceptive perception is integrated by the brain with the exteroceptive perception of stimuli from the environment, for example with those of the sense of sight or hearing. Exteroception permanently informs the human being about the conditions of his environment. Only through sensory integration does the brain establish relationships between the stimuli and thus, for example, correlate exteroceptive with interoceptive information. An example of this is the perception of gravity, which is integrated with the movements of one’s own body and thus brought into relationship with the ground. In this way, a person can react adequately to his environment and the stimuli from his body. The stimuli flow to the brain as sensations in an optimally organized manner, so that the human being can form overall perceptions from the individual sensations. He can adjust his behavior to these overall perceptions. Only people with organized perceptions can move appropriately in the environment, process all stimuli successfully or coordinate the force and extent of their movements appropriately. The ability to integrate thus influences, for example, body awareness. Integration requires and at the same time conditions an adequate ability to concentrate and to act. Thanks to integration, a gravity stimulus on the vestibular system of the inner ear, for example, results in a provision of proprioceptive muscle activity. Similarly, thanks to integration, vestibular stimuli stimulate various receptors in the arcuate pathways of the human ear, resulting in a postural adjustment that prevents people from falling. Sensory integration is also an important process in connection with the sense of sight and touch. In writing, for example, thanks to integration, the sense of sight controls the hand by integrating its perceptions with the tactile touch stimuli of the skin receptors and the proprioceptive depth-sensitive stimuli of the joint, muscle, and tendon receptors.
Diseases and disorders
Sensory integration disorder is known as a disturbed interaction of individual sensory modalities.For example, if vestibular stimuli do not trigger postural adaptation, integration in the vestibular system is disturbed. Sufferers of this disorder often suffer from low basic muscle tension, so that conscious effort is required to maintain postural stability. Because they must consciously pay attention to the act, they lack this attention for other actions. Patients with sensory integration disorders sometimes appear as if they have attention deficit disorder. However, unlike attention deficit disorder, the reason for their restlessness is not a general lack of attention. Instead, the restlessness is caused by hypotonicity of the mucosa, which fully absorbs the attention and concentration of the affected person. Other integration disorders manifest as tactile or proprioceptive hyposensitivity, which can result in lack of movement planning and often manifests as clumsiness. Also possible are tactile and vestibular hypersensitivities, which are usually the result of inadequate stimulus modulation by the central nervous system. Affected individuals often show tactile defensiveness to touch. All sensory integration disorders are brain physiological dysfunctions caused by inadequate linkage of neurons or brain structures. Partly they exist from birth, partly the integration develops poorly due to insufficient physical movements – especially in childhood. This is another reason why physical play is enormously important. Sometimes neurological diseases such as multiple sclerosis or strokes also disturb the sensory-integrative function in the perceptual chain. However, such integration disorders caused by morphological brain changes are not called sensory integration disorders in technical language. Existing disorders of integration can be attenuated by means of sensory integration therapy, although not completely eliminated. For dysfunctional integration after morphological brain changes in the context of neurological diseases, a much worse prognosis applies. Often, the impaired integration is irreversible after the destruction of brain tissue and neural tissue.
