Review of Sensory Integration Therapy for Children With Cerebral Palsy

Cerebral palsy (CP) refers to a group of non-progressive brain disorders. Several different approaches are used to treat cerebral palsy children like neurodevelopmental therapy (NDT), sensory integration therapy (SIT), and hippotherapy. Sensory integration therapy is a clinically based approach that places an emphasis on the relationship between the therapist and the child and uses play-based sensory and motor activities to encourage analysis and integration. SIT seems to offer a lot of therapeutic prospects. It uses various interventions. According to sensory integration therapists, some impacts of SIT include an improved ability to concentrate in academic, therapeutic, and social settings. Sensory integration treatment is successful in enhancing gait, balance, and gross motor function.

based assessment that assesses gross muscle activity of children up to the age of 12 years in a variety of areas, including movement, posture, and equilibrium, and assigns a severity level to each of those areas. Level I denotes minimal restrictions (e.g., walking freely), while level V implies critical restrictions (e.g., needing a wheelchair). After being classified with GMFCS, individuals may be observed as they grow to see whether therapies result in enhancing GMFCS levels [6]. Also, the Gross Motor Function Measure-88 scale (GMFM-88), a renowned standard tool that has already been used since 1993 and has been demonstrated to be a valid and accurate assessment scale, is typically used to assess the muscle function of CP patients [7].

Different approaches used in CP
Exercise is an important approach for a child with spastic diplegic CP and is characterized as an organized, systematic, and repetitive practice that tries to enhance fitness. Because of their effects on the basic impairments of CP, aerobic and resistance exercise may enhance activity and involvement. Strength training, endurance training, and cardiovascular health are all aspects of physical fitness that exercise can help with. Resistance training is all about working or sustaining against an imposed force. The application of force is commonly done with body weight, weight training, mechanical weights, and TheraBands (TheraBand, Akron, Ohio, United States). Exercise could also improve a child with CP in contexts of pain reduction and standard of living [8].
Neurodevelopmental therapy (NDT) is the most frequently applied treatment technique for children with CP. The goal of targeting the central neurological and neuromuscular system helps the brain to increase motor efficacy and functional independence by enabling standard postural-control motions. One of the principles of NDT is task-oriented training, which has been proven to be very effective and convenient in enhancing performance by encouraging intensive, purposeful, and goal-oriented practice. The therapist's hands-on treatment of trunk activation in standing and sitting positions is included in the therapy session. Weight transfers and trunk elongation on ideal trunk alignments in standing and seated posture are several pursuits. All of these activities help children with CP improve trunk strength, balance, and gross motor coordination [9].
Children with CP benefit from dynamic surface exercise therapy as it improves trunk coordination and gross motor activity. When they work out on a dynamic interface, they get proprioceptive as well as sensory input related to the positions of respective body segments in space, and adapted motor coordination reactions to stimulus. Sensory-motor inputs can be improved by activities that take place in an unstable setting with a feedback mechanism [10]. Activities to activate muscles of the trunk on a physioball (Swiss ball) have been demonstrated to increase trunk muscular strength in healthy subjects. In a three-dimensional (3D) area, a variable field will maintain the state of arousal at the proper level. When the activities are conducted on an uneven surface instead of on a couch, the possible muscle stimulation is improved more. Because the motion of the ground underneath the individual causes postural perturbations, the muscles' response to maintain the ideal posture will be more prominent [11].
Some studies have briefly looked into the benefits of rehabilitation robots in restoring gait function in children with CP. Robot-assisted gait training (RAGT) has been proven to enhance gait velocity, gait stamina, and gross motor control in children with CP. Furthermore, most of the prior research has emphasized the results of RAGT on children with CP while incorporating stationary robotics like the Lokomat® (DIH Medical, Beijing, China), although less is featured regarding the effect of wearing exoskeleton robots. Moreover, there aren't many studies that have looked into the effects of wearable exoskeletons on gait kinetics and kinematics. Honda Walking Assist (HWA) (Honda Motor Co., Ltd, Minato City, Tokyo, Japan) is a movable exoskeleton-type device that supports hip extension as well as flexion among both limbs while locomotion. The HWA only aids one joint and does not restrict the level of flexibility in other joints, which will be enough for adequate gait learning [12].
In the therapeutic context, a variety of devices is utilized in addition to conventional therapy to assist children to strengthen their walking abilities. The treadmill is a type of device that has often been utilized for nervous system therapy. Through repetitive weight loading on a participant's lower extremities, the treadmill successfully develops gait ability. Multiple systematic reviews have reported the significant impacts of repetitive task-oriented learning employing the treadmill on motor development among individuals [13].
Hippotherapy (HPT) is an equine-assisted treatment that involves the particular movement of horses to improve neurological functions and sensory processing in individuals with neurological diseases. In recent times, research into HPT as an adjunct treatment to established therapies has expanded. HPT is focused on two basic systems that involve the conveyance of heat, and the transmission of 3D motions by periodic stimuli from the horse towards the child's body. The child's pelvis is transferred in a manner that is regular, repetitive, and gentle, comparable to the motion that occurs in human gait. This 3D practice enhances postural balance and trunk straightening by stimulating balance responses. The alternate raising up of the horse's back, which causes anteversion/retroversion, elevation/depression, and also lateral motion with rotation, gives movements in all movement planes. HPT also delivers sensory information and promotes improved posture stability and motor coordination [14].

Sensory integration therapy (SIT)
SIT is a clinical-based technique that emphasizes the therapist-child interaction and employs play-based sensory and motor exercises to promote sensation processing and integration. SIT appears to have significant potential as a treatment [15]. Occupational therapists use this technique to assist children to develop their sensory processing and integration so that they can respond appropriately to everyday stimuli [16]. Sensory processing is receiving, trying to organize, and interpreting data via sensory inputs (e.g., touch, smell, taste, sight, hearing, and vestibular) to create an appropriate reaction. Different interventions that are used in SIT are given in Table 1 [17,18].

Intervention Contents
Visual processing tasks Block designs, matching shapes in photographs, puzzles, identifying geometric forms and alphabets, numbers, and categorization.  Ayres defines sensory integration as the potential to develop adequate motor and behavioral reactions to stimulus. According to her, these people had issues with registration (input detection and processing), modulation (input inhibition or transmission), associating with a few items, and/or motivation. She linked registration and modulation with two neural structures: the limbic system and the vestibular and proprioceptive systems [19]. The vestibular system processes the sensory perceptions from physical movements across space. The sensory information from muscles and joints is processed by the proprioceptive system. If it is impeded it can cause complications like hand flapping. Balls, swings, trampolines, brushes, and other devices meant to evoke proprioception, and tactile, and vestibular demands are utilized to give such sensations in playing. Deep pressure, joint compression, oral moral workouts, and body massage can all be used to increase arousal levels. Proprioceptors in muscles and joints, inner ear receptors, and auditory, visual, and tactile receptors on the skin are all triggered by activities that target many sensory systems at a time [16]. According to a new definition of SI developed from the nomenclature of sensory integration, the disorder is "difficulty detecting, modulating, interpreting, and/or responding to sensory inputs, which is severe enough to disrupt participation in everyday living activities and routines, as well as learning" [20]. Sensory integration therapists state a few effects of SIT, increased capacity to concentrate in academic, clinical, and contextual situations, decreased unwanted behavior such as selfharming actions, and better brain functionality in skills such as language and reading [21].

Review Methods
An electronic search was done in PubMed, Cumulated Index to Nursing and Allied Health Literature (CINAHL), Google Scholar, and Science Direct. Search terms used were sensory integration therapy, spastic diplegic CP, cerebral palsy, and different approaches used in cerebral palsy. In the same search, the Boolean terms used were "WITH", "AND", and "OR".
Types of the study included literature reviews, systematic reviews, randomized controlled trials (RCTs), and experimental studies. A summary of selecting the articles has been given as per PRISMA guidelines in Figure  1.

Effect of SIT to Improve Gross Motor Function
According to Shamsoddini and Hollisaz, the SIT approach had a considerable beneficial impact on gross motor functioning in children with CB. To enhance motor function, in each session, children were sustained on forearms and hands in sitting, quadruped, half-kneeling, and standing postures, with the OT (occupational therapist) assisting them unless tone attenuation was accomplished. After the child had achieved the ability to hold the training positions, a CP ball and tilt board were used to promote balancing and corrective reflexes. Ambulation practice (crawling, creeping, walking in a half-kneeling posture, and stepping on parallel bars) was provided at the appropriate motor stage of development [22].
A study by Mahaseth et al. states that SIT improves a children's capacity to analyze and integrate sensory data by incorporating various visual processing, kinesthetic awareness, tactile awareness, visuomotor coordination development, and vestibular and proprioceptive activities [18].
Vestibular and proprioceptive programs promote balance and awareness of position. Sensory motor development occurs throughout the first two years of a child's life, when the kid learns to integrate big muscles of the legs, trunk, with arms, as well as tiny muscles of the hands, by a variety of sensory stimuli. The outcome of sensory-motor stimulation on the gross and fine motor components is significant [23]. Sensory integration aids in the development of a mental as well as physical structure inside a person's nervous system that allows them to effectively process sensory information, manage their reactions, and comprehend the meaning of a specific texture, motion, or voice. Tahir et al. stated that in children with CP (spastic diplegia), SIT seemed to have a considerable beneficial impact on gross motor function. The exercises were created to provide active stretching, muscular strengthening, and bearing weight on the knees, feet, and hands. The body of the kid was placed into various poses, such as downward dog, wheelbarrow walking, and kids' yoga, which provided dynamic stretches and increased bilateral synchronization [24].
Long-term therapy is required for children with CP to enhance their motor function, which includes 24-hour postural management such as special seating, night positioning, and standing frames, which is critical not just in avoiding musculoskeletal problems such as joint contractures, musculoskeletal defects, dislocations, subluxations, and reduced bone density, but also in producing a beneficial impact on the nervous system, muscle tone, spasticity, exaggerated reflexes, and kinesthetic sense [25].
Posture care is a specifically chosen treatment strategy that has a favorable influence on a child's body functioning and structure while also facilitating increased mobility and participation and accordingly improving gross motor function. As per the placement during the daytime and nighttime, since spastic cerebral palsy children have impaired joint and kinesthetic sensation, sitting, semi-reclining, and side-lying enhance oxygen saturation (SpO2) when compared to supine lying. By aiding upper limb function, appropriate sitting aids in the development of functioning in children. Feet rest, hip belts, cutout tables, and individual-based seat angles are all vital components of a good comfortable position. According to the literature, the most supportive feeding posture is an erect sitting posture with back support and head aligned with the trunk [26].

Effect of SIT on Balance and Gait
The somatosensory, vestibular, and visual systems are responsible for posture and mobility regulation. This knowledge facilitates the CNS in anticipating the forces that are delivered to the body and then generating enough muscle activation to sustain posture [27]. Conversely, each sensory input has its significance and value, and the dependability of one sort of sensory information can impact the reliability of another [28]. Vestibular stimulation generates appropriate postural reactions by altering somatosensory and visual system sensitivity, implying sensory integration [29].
The results of Seyam et al. revealed that adding SIT to children with spastic CP enhanced their gait in both spatial and temporal aspects. According to their study, Sensory integration treatment markedly enhanced gait patterns among children with hemiplegic CP [30].
Children can develop their posture stability and motor abilities by getting specialized and appropriate sensory stimuli during therapy. As a result, their interaction might be improved with the environment and social participation [31]. Pavao et al. conducted a search of the literature on sensory information alteration as well as its implication on postural stabilization in children with CP, as well as a review of comprehensive articles on the subject. Visual information as well as proprioceptive data were mentioned in the research as essential regulating processes of postural control in children with CP [32].
Research conducted by Hussein et al. says that, since the gait has recently needed different attentional resources, the children obtain proprioceptive input (motor task) plus visual feedback using appearing lights on the display (cognitive task) when walking on the Tekscan walkway platform (Tekscan, Inc., Norwood, Massachusetts, United States). As a result, it could be more efficient than typical gait training in terms of improving spatial and temporal gait variables [33].
A summary of a few articles is given in Table 2.

Conclusions
CP is a common disorder of development and movement that affects a lot of children and they present with a gamut of deficits therefore they should be rectified with the use of an appropriate strategy of treatment. Improving their activities of daily living and functionality is always a challenge. Treatments for children with CP are beneficial in several ways. SIT though not new but an important one. Sensory integration treatment focuses on a few distinct areas of rehabilitation, such as vision, touch, and proprioception. SIT is also asserted to be successful in enhancing gait, balance, and gross motor functioning. As a result, it could be useful in learning new motor skills.

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