<unk>  is defined as "a group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain." While movement problems are the central feature of<unk> , difficulties with thinking, learning, feeling, communication and behavior often co-occur, with 28% having epilepsy, 58% having difficulties with communication, at least 42% having problems with their vision, and 2356% having learning disabilities. Muscle contractions in people with<unk>  are commonly thought to arise from overactivation.<unk>  is characterized by abnormal muscle tone, reflexes, or motor development and coordination. The neurological lesion is primary and permanent while orthopedic manifestations are secondary and progressive. In<unk>  unequal growth between muscle-tendon units and bone eventually leads to bone and joint deformities. At first, deformities are dynamic. Over time, deformities tend to become static, and joint contractures develop. Deformities in general and static deformities in specific (joint contractures) cause increasing gait difficulties in the form of tip-toeing gait, due to tightness of the Achilles tendon, and scissoring gait, due to tightness of the hip adductors. These gait patterns are among the most common gait abnormalities in children with<unk> . However, orthopaedic manifestations of<unk>  are diverse. Additionally, crouch gait (excessive knee flexion gait) is prevalent among children who possess the ability to walk. The effects of<unk>  fall on a continuum of motor dysfunction, which may range from slight clumsiness at the mild end of the spectrum to impairments so severe that they render coordinated movement virtually impossible at the other end of the spectrum. Although most people with<unk>  have problems with increased muscle tone, some have normal or low muscle tone. High muscle tone can either be due to spasticity or dystonia. Babies born with severe<unk>  often have irregular posture; their bodies may be either very floppy or very stiff. Birth defects, such as spinal curvature, a small jawbone, or a small head sometimes occur along with<unk> . Symptoms may appear or change as a child gets older. Babies born with<unk>  do not immediately present with symptoms. Classically,<unk>  becomes evident when the baby reaches the developmental stage at 6 to 9 months and is starting to mobilise, where preferential use of limbs, asymmetry, or gross motor developmental delay is seen. Drooling is common among children with<unk> , which can have a variety of impacts including social rejection, impaired speaking, damage to clothing and books, and mouth infections. It can additionally cause choking. An average of 55.5% of people with<unk>  experience lower urinary tract symptoms, more commonly excessive storage issues than voiding issues. Those with voiding issues and pelvic floor overactivity can deteriorate as adults and experience upper urinary tract dysfunction. Children with<unk>  may also have sensory processing issues. Adults with<unk>  have a higher risk of respiratory failure. Skeleton For bones to attain their normal shape and size, they require the stresses from normal musculature. People with<unk>  are at risk of low bone mineral density. The shafts of the bones are often thin (gracile), and become thinner during growth. When compared to these thin shafts (diaphyses), the centres (metaphyses) often appear quite enlarged (ballooning). Due to more than normal joint compression caused by muscular imbalances, articular cartilage may atrophy, leading to narrowed joint spaces. Depending on the degree of spasticity, a person with<unk>  may exhibit a variety of angular joint deformities. Because vertebral bodies need vertical gravitational loading forces to develop properly, spasticity and an abnormal gait can hinder proper or full bone and skeletal development. People with<unk>  tend to be shorter in height than the average person because their bones are not allowed to grow to their full potential. Sometimes bones grow to different lengths, so the person may have one leg longer than the other. Children with<unk>  are prone to low trauma fractures, particularly children with higher Gross Motor Function Classification System (GMFCS) levels who cannot walk. This further affects a child's mobility, strength, and experience of pain, and can lead to missed schooling or child abuse suspicions. These children generally have fractures in the legs, whereas non-affected children mostly fracture their arms in the context of sporting activities. Hip dislocation and ankle equinus or plantar flexion deformity are the two most common deformities among children with<unk> . Additionally, flexion deformity of the hip and knee can occur. Torsional deformities of long bones such as the femur and tibia are also encountered, among others. Children may develop scoliosis before the age of 10 – estimated prevalence of scoliosis in children with<unk>  is between 21% and 64%. Higher levels of impairment on the GMFCS are associated with scoliosis and hip dislocation. Scoliosis can be corrected with surgery, but<unk>  makes surgical complications more likely, even with improved techniques. Hip migration can be managed by soft tissue procedures such as adductor musculature release. Advanced degrees of hip migration or dislocation can be managed by more extensive procedures such as femoral and pelvic corrective osteotomies. Both soft tissue and bony procedures aim at prevention of hip dislocation in the early phases or aim at hip containment and restoration of anatomy in the late phases of disease. Equinus deformity is managed by conservative methods especially when dynamic. If fixed/static deformity ensues surgery may become mandatory. Growth spurts during puberty can make walking more difficult for people with<unk> . Eating Due to sensory and motor impairments, those with<unk>  may have difficulty preparing food, holding utensils, or chewing and swallowing. An infant with<unk>  may not be able to suck, swallow or chew. Gastro-oesophageal reflux is common in children with<unk> . Children with<unk>  may have too little or too much sensitivity around and in the mouth. Poor balance when sitting, lack of control of the head, mouth, and trunk, not being able to bend the hips enough to allow the arms to stretch forward to reach and grasp food or utensils, and lack of hand-eye coordination can make self-feeding difficult. Feeding difficulties are related to higher GMFCS levels. Dental problems can also contribute to difficulties with eating. Pneumonia is also common where eating difficulties exist, caused by undetected aspiration of food or liquids. Fine finger dexterity, like that needed for picking up a utensil, is more frequently impaired than gross manual dexterity, like that needed for spooning food onto a plate. Grip strength impairments are less common. Children with severe<unk> , particularly with oropharyngeal issues, are at risk of undernutrition. Triceps skin fold tests have been found to be a very reliable indicator of malnutrition in children with<unk> . Language Speech and language disorders are common in people with<unk> . The incidence of dysarthria is estimated to range from 31% to 88%, and around a quarter of people with<unk>  are non-verbal. Speech problems are associated with poor respiratory control, laryngeal and velopharyngeal dysfunction, and oral articulation disorders that are due to restricted movement in the oral-facial muscles. There are three major types of dysarthria in<unk> : spastic, dyskinetic (athetotic), and ataxic. Early use of augmentative and alternative communication systems may assist the child in developing spoken language skills. Overall language delay is associated with problems of cognition, deafness, and learned helplessness. Children with<unk>  are at risk of learned helplessness and becoming passive communicators, initiating little communication. Early intervention with this clientele, and their parents, often targets situations in which children communicate with others so that they learn that they can control people and objects in their environment through this communication, including making choices, decisions, and mistakes. Pain and sleep Pain is common and may result from the inherent deficits associated with the condition, along with the numerous procedures children typically face. When children with<unk>  are in pain, they experience worse muscle spasms. Pain is associated with tight or shortened muscles, abnormal posture, stiff joints, unsuitable orthosis, etc. Hip migration or dislocation is a recognizable source of pain in<unk>  children and especially in the adolescent population. Nevertheless, the adequate scoring and scaling of pain in<unk>  children remains challenging. Pain in<unk>  has a number of different causes, and different pains respond to different treatments. There is also a high likelihood of chronic sleep disorders secondary to both physical and environmental factors. Children with<unk>  have significantly higher rates of sleep disturbance than typically developing children. Babies with<unk>  who have stiffness issues might cry more and be harder to put to sleep than non-disabled babies, or "floppy" babies might be lethargic. Chronic pain is under-recognized in children with<unk> , even though 3 out of 4 children with<unk>  experience pain. Adults with<unk>  also experience more pain than the general population. Associated disorders Associated disorders include intellectual disabilities, seizures, muscle contractures, abnormal gait, osteoporosis, communication disorders, malnutrition, sleep disorders, and mental health disorders, such as depression and anxiety. In addition to these, functional
Cerebral palsy
Lesch–Nyhan syndrome
Athetoid cerebral palsy
Angelman syndrome
Spastic cerebral palsy
Tardive dyskinesia  Tardive dyskinesia  1
Spina bifida
Snyder–Robinson syndrome