Doublecortin positive cells, similar to stem cells, are extremely adaptable and, when extracted from a brain, cultured and then re-injected in a lesioned area of the same brain, they can help repair and rebuild it. The treatment using them would take some time to be available for general public use, as it has to clear regulations and trials.

Spastic quadriplegia can be diagnosed as early as age one after a noticed delay in development, particularly a delay in rolling, crawling, sitting, or walking. However, depending on the severity, signs may not show up until the age of three. Muscle tone is sometimes used to make the diagnosis for spastic quadriplegia as affected children often appear to be either too stiff or too floppy.

Another important diagnostic factor is the persistence of primitive reflexes past the age at which they should have disappeared (6–12 months of age). These reflexes include the rooting reflex, the sucking reflex, and the Moro reflex, among others.

Magnetic resonance imaging (MRI) or a computed tomography scan (CT scan) may be used to locate the cause of the symptoms. Ultrasound may be used for the same function in premature babies.

Because cerebral palsy refers to a group of disorders, it is important to have a clear and systematic naming system. These disorders must be non-progressive, non-transient, and not due to injury to the spinal cord. Disorders within the group are classified based on two characteristics- the main physiological symptom, and the limbs that are affected. For a disorder to be diagnosed as spastic quadriplegia, an individual must show spastic symptoms (as opposed to athetotic, hypertonic, ataxic, or atonic symptoms) and it must be present in all four limbs (as opposed to hemiplegic, diplegic, or triplegic cases).

While a diagnosis may be able to be made shortly after birth based on family history and observation of the infant, it is often postponed until after the child is between 18–24 months old in order to monitor the possible regression or progression of symptoms.

Diagnosis of ataxic cerebral palsy is based on clinical assessment using standardized assessment tools. Diagnosis begins with the observation of slow motor development, abnormal muscle tone, and unusual posture in children that fail to reach developmental milestones. Diagnosis differs in adults and children because a child’s brain is still developing and acquiring new motor, linguistic, adaptive, and social skills. The testing strategy is based on the pattern of development of symptoms, the patient’s family history, and any factors that might influence the diagnosis, such as injury or trauma. Associated disabilities such as those previously described under symptoms associated with ataxic cerebral palsy, i.e., sensory impairment and cognitive dysfunction, are also helpful in diagnosing the disease.

In children, assessment of infantile reflexes is also a diagnostic tool, such as the Moro reflex and the Romberg Test. The Moro reflex is rarely present in infants after 6 months of age and is characterized as a response to a sudden loss of support that causes the infant to feel like it is falling. The infant will respond by abduction and adduction (or spreading and unspreading) of the arms, as well as crying. The Moro reflex is significant in evaluating the integration of the central nervous system and patients with ataxic cerebral palsy will show a persistence and exacerbation of the reflex. In addition, patients with ataxic cerebral palsy will rarely show a positive Romberg test, which indicates that there is localized cerebellar dysfunction.

Physical diagnostic tests, such as cerebral imaging using Computerized Tomography (CT), Magnetic Resonance Imaging (MRI), and ultrasound are also useful, but not preferred to clinical assessments. These neuroimaging techniques can show brain abnormalities that have been found in previous patients with cerebral palsy, i.e., focal infarction and various brain malformations, however in a study of 273 children who were born after 35 weeks of gestation and underwent neuroimaging studies, one-third of the infants showed normal studies. In addition, infants undergo neuroimaging studies once the infant has neurological findings suggestive of cerebral palsy.

For developmental diagnosis in children and infants, there are a number of milestones of motor, linguistic, adaptive, and social behavior, such as.

1. When the child could sit up on their own with or without support

2. Say their first words

3. Feed themselves

4. Play successfully with children of same age

The muscle spasticity can cause gait patterns to be awkward and jerky. The constant spastic state of the muscle can lead to bone and tendon deformation, further complicating the patient's mobility. Many patients with spastic hemiplegia are subjected to canes, walkers and even wheelchairs. Due to the decrease in weight bearing, patients are at a higher risk of developing osteoporosis. An unhealthy weight can further complicate mobility. Patients with spastic hemiplegia are a high risk for experiencing seizures. Oromotor dysfunction puts patients at risk for aspiration pneumonia. Visual field deficits can cause impaired two-point discrimination. Many patients experience the loss of sensation in the arms and legs on the affected side of the body. Nutrition is essential for the proper growth and development for a child with spastic hemiplegia.

Hereditary spastic paraplegias can be classified based on the symptoms; mode of inheritance; the patient’s age at onset; the affected genes; and biochemical pathways involved.

In any manifestation of spastic CP, clonus of the affected limb(s) may intermittently result, as well as muscle spasms, each of which results from the pain and/or stress of the tightness experienced, indicating especially hard-working and/or exhausted musculature. The spasticity itself can and usually does also lead to very early onset of muscle-stress symptoms like arthritis and tendinitis, especially in ambulatory individuals in their mid-20s and early-30s. As compared to other types of CP, however, and especially as compared to hypotonic CP or more general paralytic mobility disabilities, spastic CP is typically more easily manageable by the person affected, and medical treatment can be pursued on a multitude of orthopaedic and neurological fronts throughout life.

Physical therapy and occupational therapy regimens of assisted stretching, strengthening, functional tasks, and/or targeted physical activity and exercise are usually the chief ways to keep spastic CP well-managed, although if the spasticity is too much for the person to handle, other remedies may be considered, such as various antispasmodic medications, botox, baclofen, or even a neurosurgery known as a selective dorsal rhizotomy (which eliminates the spasticity by eliminating the nerves causing it).

Incomplete spinal cord injuries result in varied post injury presentations. There are three main syndromes described, depending on the exact site and extent of the lesion.

1. The central cord syndrome: most of the cord lesion is in the gray matter of the spinal cord, sometimes the lesion continues in the white matter.

2. The Brown–Séquard syndrome: hemi section of the spinal cord.

3. The anterior cord syndrome: a lesion of the anterior horns and the anterolateral tracts, with a possible division of the anterior spinal artery.

For most patients with ASIA A (complete) tetraplegia, ASIA B (incomplete) tetraplegia and ASIA C (incomplete) tetraplegia, the International Classification level of the patient can be established without great difficulty. The surgical procedures according to the International Classification level can be performed. In contrast, for patients with ASIA D (incomplete) tetraplegia it is difficult to assign an International Classification other than International Classification level X (others). Therefore, it is more difficult to decide which surgical procedures should be performed. A far more personalized approach is needed for these patients. Decisions must be based more on experience than on texts or journals.

The results of tendon transfers for patients with complete injuries are predictable. On the other hand, it is well known that muscles lacking normal excitation perform unreliably after surgical tendon transfers. Despite the unpredictable aspect in incomplete lesions tendon transfers may be useful. The surgeon should be confident that the muscle to be transferred has enough power and is under good voluntary control. Pre-operative assessment is more difficult to assess in incomplete lesions.

Patients with an incomplete lesion also often need therapy or surgery before the procedure to restore function to correct the consequences of the injury. These consequences are hypertonicity/spasticity, contractures, painful hyperesthesias and paralyzed proximal upper limb muscles with distal muscle sparing. Spasticity is a frequent consequence of incomplete injuries. Spasticity often decreases function, but sometimes a patient can control the spasticity in a way that it is useful to their function. The location and the effect of the spasticity should be analyzed carefully before treatment is planned. An injection of Botulinum toxin (Botox) into spastic muscles is a treatment to reduce spasticity. This can be used to prevent muscle shorting and early contractures.

Over the last ten years an increase in traumatic incomplete lesions is seen, due to the better protection in traffic.

PBP is aggressive and relentless, and there were no treatments for the disease as of 2005. However, early detection of PBP is the optimal scenario in which doctors can map out a plan for management of the disease. This typically involves symptomatic treatments that are frequently used in many lower motor disorders.

In the industrialized world, the incidence of overall cerebral palsy, which includes but is not limited to spastic diplegia, is about 2 per 1000 live births. Thus far, there is no known study recording the incidence of CP in the overall nonindustrialized world. Therefore, it is safe to assume that not all spastic CP individuals are known to science and medicine, especially in areas of the world where healthcare systems are less advanced. Many such individuals may simply live out their lives in their local communities without any medical or orthopedic oversight at all, or with extremely minimal such treatment, so that they are never able to be incorporated into any empirical data that orthopedic surgeons or neurosurgeons might seek to collect. It is shocking to note that—as with people with physical disability overall—some may even find themselves in situations of institutionalization, and thus barely see the outside world at all.

From what "is" known, the incidence of spastic diplegia is higher in males than in females; the Surveillance of Cerebral Palsy in Europe (SCPE), for example, reports a M:F ratio of 1.33:1. Variances in reported rates of incidence across different geographical areas in industrialized countries are thought to be caused primarily by discrepancies in the criteria used for inclusion and exclusion.

When such discrepancies are taken into account in comparing two or more registers of patients with cerebral palsy and also the extent to which children with mild cerebral palsy are included, the incidence rates still converge toward the average rate of 2:1000.

In the United States, approximately 10,000 infants and babies are born with CP each year, and 1200–1500 are diagnosed at preschool age when symptoms become more obvious. It is interesting to note that those with extremely mild spastic CP may not even be aware of their condition until much later in life: Internet chat forums have recorded men and women as old as 30 who were diagnosed only recently with their spastic CP.

Overall, advances in care of pregnant mothers and their babies has not resulted in a noticeable decrease in CP; in fact, because medical advances in areas related to the care of premature babies has resulted in a greater survival rate in recent years, it is actually "more" likely for infants with cerebral palsy to be born into the world now than it would have been in the past. Only the introduction of quality medical care to locations with less-than-adequate medical care has shown any decreases in the incidences of CP; the rest either have shown no change or have actually shown an increase. The incidence of CP increases with premature or very low-weight babies regardless of the quality of care.

There is no known cure for cerebral palsy, however there is a large array of treatments proven effective at improving quality of life and relieving some of the symptoms associated with CP, especially SHCP. Some treatments are aimed at improving mobility, strengthening muscle and improving coordination. Although CP is due to permanent damage and is not progressive in nature, without treatment the symptoms can become worse, intensifying in pain and severity, and create complications that were not initially present. Some treatments are preventative measures to help prevent further complications, such as complete paralysis of the arm due to non-use and subsequent worsening hypertonia and joint contracture. Others forms of treatment are corrective in nature. Many treatments target symptoms that are indirectly related to or caused by the SHCP. Many of these treatments are common for other forms of CP as well. Treatment is individualized based on each case and the specific needs of the patient. Treatments are often combined with other forms of treatment and a long term treatment plan is created and continuously evaluated. Treatment can include the following:

- "Physical therapy" – Physical therapy is the most common form of treatment (source needed). It may include sensory stimulation, stretching, strengthening and positioning. Constraint-induced movement therapy is a newer form of physical therapy for SHCP that involves casting or splinting the unaffected arm to promote use of the affected arm (Taub). The theory behind constraint-induced movement therapy is that new neural pathways are created. Alternative forms of physical therapy include yoga and dance. Physical therapy may also include the use of braces while not actively involved with the therapist.

- "Occupational therapy" – Occupational therapy evaluates and treats patients through selected activities in order to enable people to function as effectively and independently as possible in daily life. Occupational therapy is geared toward the individual to achieve optimal results and performance while learning to cope with their disability.

- "Speech therapy" – Due to difficulties in speech, speech therapy is often necessary. Aside from helping with understanding language and increasing communication skills, speech therapists can also assist children that have difficulty eating and drinking.

- "Behavioral therapy" — Psychotherapy and counseling are heavily used in treatment of individuals with SHPD to help them cope emotionally with their needs and frustrations. Counseling through social work can be very beneficial for social issues and adjustments to society. Psychotherapy becomes a more important aspect of therapy when more serious issues such as depression become problematic. Play therapy is a common treatment for all young children with or without disabilities, but can be very useful helping children with SHCP. This therapy again is individualized geared to improve emotional and social development; reduce aggression; improve cooperation with others; assist a child in processing a traumatic event or prepare for an upcoming event such as surgery.

- "Surgery" – Although surgery may become necessary in some cases, physical therapy and the consistent use of braces can help mitigate the need for surgery. Surgical procedures are painful with long and difficult recoveries and do not cure the condition. Most common, is surgery that effectively lengthens the muscle. This type of surgery is usually performed on the legs, but can be performed on the arms as well. Surgeries also may be necessary to realign joints. Other, less popular surgical techniques try to reduce spasticity by severing selected overactive nerves that control muscles. This procedure, known as selective dorsal root rhizotomy, is still somewhat controversial, and is generally used only on the lower extremities of severe cases. Other experimental surgical techniques are also being investigated. The benefits of surgery can also be negated or reversed if the patient does not participate in physical therapy and braces (or casts) are not worn regularly.

- "Medicinal" – Medication targeting symptoms associated with spasticity is also a relatively new treatment that is utilized, but is still in the early stages of development. Drugs such as baclofen, benzodiazepines (e.g., diazepam), tizanidin, and sometimes dantrolene have shown promise in the effort to diminish spasticity. Botulinum toxin ("Botox") type A may reduce spasticity a few months at a time and has frequently been considered a beneficial treatment for children with SHCP and other forms of CP. Botox has been shown to be especially beneficial to reducing spasticity in the gastrocnemius (calf) muscle. This therapy can improve range of motion, reduce deformity, improve response to occupational and physical therapy, and delay the need for surgery. Botox injections have also shown advantages for upper extremities. There is still some doubt for the effectiveness, and some side effects to the relaxed muscles have been a loss of strength for patients with some muscle control. Casting, in conjunction with Botox injections may be an additional option for better results. Research is constantly investing in new improvements and more experimental therapy and treatment.

Initial diagnosis of HSPs relies upon family history, the presence or absence of additional signs and the exclusion of other nongenetic causes of spasticity, the latter being particular important in sporadic cases.

Cerebral and spinal MRI is an important procedure performed in order to rule out other frequent neurological conditions, such as multiple sclerosis, but also to detect associated abnormalities such as cerebellar or corpus callosum atrophy as well as white matter abnormalities. Differential diagnosis of HSP should also exclude spastic diplegia which presents with nearly identical day-to-day effects and even is treatable with similar medicines such as baclofen and orthopedic surgery; at times, these two conditions may look and feel so similar that the only "perceived" difference may be HSP's hereditary nature versus the explicitly non-hereditary nature of spastic diplegia (however, unlike spastic diplegia and other forms of spastic cerebral palsy, HSP cannot be reliably treated with selective dorsal rhizotomy).

Ultimate confirmation of HSP diagnosis can only be provided by carrying out genetic tests targeted towards known genetic mutations.

Movement and posture limitations are aspects of all CP types and as a result, CP has historically been diagnosed based on parental reporting of developmental motor delays such as failure to sit upright, reach for objects, crawl, stand, or walk at the appropriate age. Diagnosis of ADCP is also based on clinical assessment used in conjunction with milestone reporting. The majority of ADCP assessments now use the Gross Motor Function Classification System (GMFCS) or the International Classification of Functioning, Disability and Health (formerly the International Classification of Impairments Disease, and Handicaps), measures of motor impairment that are effective in assessing severe CP. ADCP is typically characterized by an individual’s inability to control their muscle tone, which is readily assessed via these classification systems.

Magnetic resonance imaging (MRI) is used to detect morphological brain abnormalities associated with ADCP in patients that are either at risk for ADCP or have shown symptoms thereof. The abnormalities chiefly associated with ADCP are lesions that appear in the basal ganglia. The severity of the disease is proportional to the severity and extent of these abnormalities, and is typically greater when additional lesions appear elsewhere in the deep grey matter or white matter. MRI also has the ability to detect brain malformation, periventricular leukomalacia (PVL), and areas affected by hypoxia-ischemia, all of which may play a role in the development of ADCP. The MRI detection rate for ADCP is approximately 54.5%, however this statistic varies depending on the patient’s age and the cause of the disease and has been reported to be significantly higher.

Delayed diagnosis of cervical spine injury has grave consequences for the victim. About one in 20 cervical fractures are missed and about two-thirds of these patients have further spinal-cord damage as a result. About 30% of cases of delayed diagnosis of cervical spine injury develop permanent neurological deficits. In high-level cervical injuries, total paralysis from the neck can result. High-level tetraplegics (C4 and higher) will likely need constant care and assistance in activities of daily living, such as getting dressed, eating and bowel and bladder care. Low-level tetraplegics (C5 to C7) can often live independently.

Even with "complete" injuries, in some rare cases, through intensive rehabilitation, slight movement can be regained through "rewiring" neural connections, as in the case of the late actor Christopher Reeve.

In the case of cerebral palsy, which is caused by damage to the motor cortex either before, during (10%), or after birth, some people with tetraplegia are gradually able to learn to stand or walk through physical therapy.

Quadriplegics can improve muscle strength by performing resistance training at least three times per week. Combining resistance training with proper nutrition intake can greatly reduce co-morbidities such as obesity and type 2 diabetes.

Current forms of prevention are focused during pregnancy, while others are focused immediately after birth. Some methods that have been used include prolonging the pregnancy using interventions such as 17-alpha progesterone, limiting the number of gestations during pregnancy (for pregnancies induced by assistive reproductive technology), antenatal steroid for mothers likely to deliver prematurely, high caffeine for premature births with extremely low birth weights.

As age increases, spasticity makes for more noticeable effects in bones and joints and muscle function. This is often mistakenly said to mean that "spasticity increases as people with spastic CP age", which is a misrepresentation of the knock-on effects of spasticity with age. The clinical reality is that spasticity intensities remain constant but an increasing age in to middle-adulthood and the early elder years self-evidently changes the body structure, body response times and body adaptiveness capabilities markedly, leading to very different interplays between the body's spasticity and the body itself as the body 'degrades' across the twilight years.

That being said, cerebral palsy, including spastic cerebral palsy, is notable for a glaring overall research deficiency—the fact that it is one of the very few "major" groups of conditions on the planet in human beings for which medical science has not yet (as of 2011) collected wide-ranging empirical data on the development and experiences of young adults, the middle aged and older adults. An especially puzzling aspect of this lies in the fact that cerebral palsy as defined by modern science was first "discovered" and specifically addressed well over 100 years ago and that it would therefore be reasonable to expect by now that at least some empirical data on the adult populations with these conditions would have long since been collected, especially over the second half of the 20th century when existing treatment technologies rapidly improved and new ones came into being. The vast majority of empirical data on the various forms of cerebral palsy is concerned near-exclusively with children (birth to about 10 years of age) and sometimes pre-teens and early teens (11–13). Some doctors attempt to provide their own personal justifications for keeping their CP specialities purely paediatric, but there is no objectively apparent set of reasons backed by any scientific consensus as to why medical science has made a point of researching adult cases of multiple sclerosis, muscular dystrophy and the various forms of cancer in young and older adults, but has failed to do so with CP.

Because the causes of CP are varied, a broad range of preventative interventions have been investigated.

Electronic fetal monitoring has not helped to prevent CP, and in 2014 the American College of Obstetricians and Gynecologists, the Royal Australian and New Zealand College of Obstetricians and Gynaecologists, and the Society of Obstetricians and Gynaecologists of Canada have acknowledged that there are no long-term benefits of electronic fetal monitoring. Prior to this, electronic fetal monitoring was widely used to prop up obstetric litigation.

In those at risk of an early delivery, magnesium sulphate appears to decrease the risk of cerebral palsy. It is unclear if it helps those who are born at term. In those at high risk of preterm labor a review found that moderate to severe CP was reduced by the administration of magnesium sulphate, and that adverse effects on the babies from the magnesium sulphate were not significant. Mothers who received magnesium sulphate could experience side effects such as respiratory depression and nausea. Caffeine is used to treat apnea of prematurity and reduces the risk of cerebral palsy in premature babies, but there are also concerns of long term negative effects. A moderate level of evidence has been shown for giving women antibiotics during preterm labour when their waters had not broken was associated with an increased risk of cerebral palsy in the child. Additionally, allowing a preterm birth to proceed rather than trying to delay the birth also had a moderate level of evidence for increased risk of cerebral palsy in the child.

Cooling high-risk full-term babies shortly after birth may reduce disability, but this may only be useful for some forms of the brain damage that causes CP.

As a matter of everyday maintenance, muscle stretching, range of motion exercises, yoga, contact improvisation, modern dance, resistance training, and other physical activity regimens are often utilized by those with spastic CP to help prevent contractures and reduce the severity of symptoms.

Major clinical treatments for spastic diplegia are:

- Baclofen (and its derivatives), a gamma amino butyric acid (GABA) substitute in oral (pill-based) or intrathecal form. Baclofen is essentially chemically identical to the GABA that the damaged, over-firing nerves cannot absorb, except that it has an extra chemical 'marker' on it that makes the damaged nerves 'think' it is a different compound, and thus those nerves will absorb it. Baclofen is noted for being the sole medication available for GABA-deficiency-based spasticity which acts on the actual cause of the spasticity rather than simply reducing symptomatology as muscle relaxants and painkillers do. The intrathecal solution is a liquid injected into the spinal fluid for trial, and if successful in reducing spasticity, thereafter administered via an intrathecal pump, which has variously been proven potentially very dangerous on one or another level with long-term use (see article), including sudden and potentially lethal baclofen overdose, whereas the oral route, which comes in 10- or 20-milligram tablets and the dosage of which can be gently titrated either upward or downward, as well as safely ceased entirely, has not.

- Antispasmodic muscle relaxant chemicals such as tizanidine and botulinum toxin (Botox), injected directly into the spastic muscles; Botox wears off every three months.

- Phenol and similar chemical 'nerve deadeners', injected selectively into the over-firing nerves in the legs on the muscle end to reduce spasticity in their corresponding muscles by preventing the spasticity signals from reaching the legs; Phenol wears off every six months.

- Orthopedic surgery to release the spastic muscles from their hypertonic state, a usually temporary result because the spasticity source is the nerves, not the muscles; spasticity can fully reassert itself as little as one year post-surgery.

- Selective dorsal rhizotomy, a neurosurgery directly targeting and eliminating ("cutting" or "lesioning") the over-firing nerve rootlets and leaving the properly firing ones intact, thereby permanently eliminating the spasticity but compelling the person to spend months re-strengthening muscles that will have been severely weakened by the loss of the spasticity, due to the fact of those muscles not really having had actual strength to begin with.

Progressive Bulbar Palsy is slow in onset, with symptoms starting in most patients around 50–70 years of age. PBP has a life expectancy typically between 6 months and 3 years from onset of first symptoms. It is subtype of the Motor Neurone Diseases (MND) accounting for around 1 in 4 cases. Amyotrophic lateral sclerosis (ALS) is another sub-type. Pure PBP without any EMG or clinical evidence of abnormalities in the legs or arms is possible, albeit extremely rare. Moreover, about twenty-five percent of patients with PBP eventually develop the widespread symptoms common to ALS.

Usually occurs within 2 periods:

1. With premature babies

2. full diagnosis usually between ages 2–5 years

Diplegia is usually not diagnosed before the age of 2 years yet the symptoms and signs of the earlier stages are typical and should enable the diagnosis to be made before the contractures have occurred. Parents suspecting diplegia should take their child to the doctor to potentially get an earlier diagnosis.

There are several different modes of treatment for people with paralysis in their upper limbs. For example, behavioral and environmental treatments may include physiotherapy, occupational therapy, motor learning, strength training, and neurodevelopment treatment. Another treatment may be through the use of splints and casts. Electrophysical agents may be used such as neuromuscular electrical stimulation (NMES). Sometimes pharmacological treatments are necessary such as Botulinum toxin type A. On more severe cases surgery of the upper limbs may be required.

The clinical underpinnings of two of the most common spasticity conditions, spastic diplegia and multiple sclerosis, can be described as follows: in spastic diplegia, the upper motor neuron lesion arises often as a result of neonatal asphyxia, while in conditions like multiple sclerosis, spasticity is thought by some to be as a result of the autoimmune destruction of the myelin sheaths around nerve endings—which in turn can "mimic" the gamma amino butyric acid deficiencies present in the damaged nerves of spastic diplegics, leading to roughly the same "presentation" of spasticity, but which clinically is fundamentally different from the latter.

Spasticity is assessed by feeling the resistance of the muscle to passive lengthening in its most relaxed state. A spastic muscle will have immediately noticeable, often quite forceful, increased resistance to passive stretch when moved with speed and/or while attempting to be stretched out, as compared to the non-spastic muscles in the same person's body (if any exist). As there are many features of the upper motor neuron syndrome, there are likely to be multiple other changes in affected musculature and surrounding bones, such as progressive misalignments of bone structure around the spastic muscles (leading for example to the scissor gait in spastic diplegia). Also, following an upper motor neuron lesion, there may be multiple muscles affected, to varying degrees, depending on the location and severity of the upper motor neuron damage. The result for the affected individual, is that they may have any degree of impairment, ranging from a mild to a severe movement disorder. A relatively mild movement disorder may contribute to a loss of dexterity in an arm, or difficulty with high level mobility such as running or walking on stairs. A severe movement disorder may result in marked loss of function with minimal or no volitional muscle activation. There are several scales used to measure spasticity, such as the King's hypertonicity scale, the Tardieu, and the modified Ashworth. Of these three, only the King's hypertonicity scale measures a range of muscle changes from the UMN lesion, including active muscle performance as well as passive response to stretch.

Assessment of a movement disorder featuring spasticity may involve several health professionals depending on the affected individual's situation, and the severity of their condition. This may include physical therapists, physicians (including neurologists and rehabilitation physicians), orthotists and occupational therapists. Assessment is needed of the affected individual's goals, their function, and any symptoms that may be related to the movement disorder, such as pain. A thorough assessment will include analysis of posture, active movement, muscle strength, movement control and coordination, and endurance, as well as spasticity (response of the muscle to stretch). Spastic muscles typically demonstrate a loss of selective movement, including a loss of eccentric control (decreased ability to actively lengthen). While multiple muscles in a limb are usually affected in the upper motor neuron syndrome, there is usually an imbalance of activity, such that there is a stronger pull in one direction, such as into elbow flexion. Decreasing the degree of this imbalance is a common focus of muscle strengthening programs. Spastic movement disorders also typically feature a loss of stabilisation of an affected limb or the head from the trunk, so a thorough assessment requires this to be analysed as well.

Secondary effects are likely to impact on assessment of spastic muscles. If a muscle has impaired function following an upper motor neuron lesion, other changes such as increased muscle stiffness are likely to affect the feeling of resistance to passive stretch. Other secondary changes such as loss of muscle fibres following acquired muscle weakness are likely to compound the weakness arising from the upper motor neuron lesion. In severely affected spastic muscles, there may be marked secondary changes, such as muscle contracture, particularly if management has been delayed or absent.

The diagnosis of cerebral palsy has historically rested on the person's history and physical examination. A general movements assessment, which involves measuring movements that occur spontaneously among those less than four months of age, appears to be most accurate. Children who are more severely affected are more likely to be noticed and diagnosed earlier. Abnormal muscle tone, delayed motor development and persistence of primitive reflexes are the main early symptoms of CP. Symptoms and diagnosis typically occur by the age of 2, although persons with milder forms of cerebral palsy may be over the age of 5, if not in adulthood, when finally diagnosed. It is a developmental disability.

Once a person is diagnosed with cerebral palsy, further diagnostic tests are optional. Neuroimaging with CT or MRI is warranted when the cause of a person's cerebral palsy has not been established. An MRI is preferred over CT due to diagnostic yield and safety. When abnormal, the neuroimaging study can suggest the timing of the initial damage. The CT or MRI is also capable of revealing treatable conditions, such as hydrocephalus, porencephaly, arteriovenous malformation, subdural hematomas and hygromas, and a vermian tumour (which a few studies suggest are present 5–22% of the time). Furthermore, an abnormal neuroimaging study indicates a high likelihood of associated conditions, such as epilepsy and intellectual disability. There is a small risk associated with sedating children in order to take a clear MRI.

The age at which CP is diagnosed is important, but there is disagreement over what is the best age to make the diagnosis. The earlier CP is diagnosed correctly, the better the opportunities are to provide the child with physical and education help, but there might be a greater chance that CP will be confused with another problem, especially if the child is 18 months of age or younger. Infants may have temporary problems with muscle tone or control that can be confused with CP, which is permanent. A metabolism disorder or tumors in the nervous system may appear to be CP; metabolic disorders, in particular, can produce brain problems that look like CP on an MRI. Disorders that deteriorate the white matter in the brain and problems that cause spasms and weakness in the legs, may be mistaken for CP when they first appear early in life. However, these disorders get worse over time, and CP does not (although it may change in character). In infancy it may not be possible to tell the difference between them. In the UK, not being able to sit independently by the age of 8 months is regarded as a clinical sign for further monitoring. Fragile X syndrome (a cause of autism and intellectual disability) and general intellectual disability must also be ruled out. Cerebral palsy specialist John McLaughlin recommends waiting until the child is 36 months of age before making a diagnosis, because by that age, motor capacity is easier to assess.

The prognosis for those with spastic muscles depends on multiple factors, including the severity of the spasticity and the associated movement disorder, access to specialised and intensive management, and ability of the affected individual to maintain the management plan (particularly an exercise program). Most people with a significant UMN lesion will have ongoing impairment, but most of these will be able to make progress. The most important factor to indicate ability to progress is seeing improvement, but improvement in many spastic movement disorders may not be seen until the affected individual receives help from a specialised team or health professional.

Among the methods of diagnosing tropical spastic paraparesis are MRI (magnetic resonance imaging) and lumbar puncture (which may show lymphocytosis).