In general, the term, Cerebral Palsy (CP), is used to refer to a disorder that arises because of brain damage that affects movement or posture. However, the vagueness of that definition could describe a multitude of disorders. CP is actually an umbrella term given to a larger group of varying non-degenerative disorders that can involve any combination of the following symptoms and related effects: muscle spasticity, involuntary movements, awkward gait patterns or the inability to walk at all, general poor balance, difficulty swallowing, microcephaly, abnormal sensation, impaired vision, abnormal perception, impaired hearing, seizures, impaired speech, inability to use certain limbs, difficulty controlling bladder or bowels, secondary symptoms due to poor posture like breathing issues, and possible learning disabilities or mental retardation. This broad array of symptoms is directly related to the areas of the brain that are damaged; since different neurons ultimately control different areas of the body, each person will have a different case because of the innumerable different possibilities of areas of the brain that could be damaged. Because of the diversity in combination of symptoms, this disorder manifests itself uniquely in each individual, with no two patients presenting exactly the same way. Patients are usually identified at a young age. Premature babies are watched very carefully for signs of CP, as they are more likely to develop the disorder than full term babies. Also, babies who have had a traumatic birth, particularly those experiencing intrapartum asphyxia will be monitored for the disorder. However, there will often be no clear indicators and parents and physicians won't have a conclusive answer until they notice developmental delay, abnormal growth charts, and abnormal reflexes in the child's well-baby and well-child visits as the child ages. Usually the physician will have a conclusive answer by age 4 and the parents can make appropriate decisions about schooling accommodations for their child.

Glossary of Terms
In order to more fully understand the following diagrams and descriptions of classification and symptoms, the following terms should be helpful.
Spasticity (spastic)- at rest muscles are resistant to passive stretch; during movement the resistance is velocity dependent; resistance is asymmetric about the joint, meaning either the flexors or extensors will be too tight, but not both
Rigidity- increased muscle tone at rest; resistance to passive stretch; resistance is independent of velocity; resistance is symmetric about the joints with both flexors and extensors resisting
Tone- tension and firmness present in muscle tissue when at rest
Ataxia (ataxic)- inability to coordinate voluntary muscle movements
Dystonia (dystonic)- muscles contracting abnormally to produce involuntary twisting movements
Dyskinesia (dyskinetic)- difficulty with performing voluntary movements
Athetoid (choreo-athetoid)- referring to involuntary writhing, twitching, or jerking

Causes of CP

Brain injury or malformation in areas that affect mobility before, during, or after birth causes CP. In addition to the varying areas of the brain that could be affected, as mentioned above, timing of this injury or malformation is also a variable. Damage to the developing brain can be caused by:

  • Cerebral Dysgenesis—refers to the brain either not developing fully or growing abnormally, both of which can include but are not limited to incomplete division or organization
  • Preventricular Leukomalacia—poor myelination by oligodendrocytes prenatally
    • Toxins from intrauterine infections cause the poor myelination by permeating the membranes surrounding the fetus and integrating with the amniotic fluid
  • Hypoxic-Ischemic Encephalopathy or Intrapartum Asphyxia—oxygen deprivation for a long enough duration to permanently damage brain tissue
    • Oxygen deprivation is common in premature infants who cannot take a big enough breath of air when they are first born; also infants who are unfortunate enough to have the umbilical cord wrapped around their neck for too lung suffer the same way
  • Neonatal Stroke—as with adults, blockage to blood vessels supplying nutrients to the developing brain can lead to permanent tissue death, not allowing for the brain to make connections to those areas
  • Genetic and environmental factors interrupting and disturbing brain cell migration to their appropriate locations prenatally
  • Trauma, infections, or asphyxia in early infancy that damage cell tissue denying the ability for the brain to make connections to those areas
  • Intracranial Hemorrhage
    • The bleeding from trauma can lead to a hematoma, which can press on areas of the developing brain and/or deprive it of blood flow, killing the tissue as a result

corticospinal tract.jpg
Anatomy and Physiology: The Unity of Form and Function, 5th Edition, Chapter 13
Functional Anatomy

Upper Motor Neurons and the Corticospinal Tract
Upper motor neurons originate in cortical layer 5 in the primary motor cortex. These cells are responsible for initiating the voluntary movements of the individual. The axons of these cells become the corticospinal tracts and synapse directly with lower motor neurons in the ventral horn. Spastic CP is caused by damage to the upper motor neurons either at the cortical level or within the pyramidal (corticospinal) tract. This is the most common form of CP.

cerebellum vmo 3.png

The Cerebellum is a multi-faceted processing network of cells taking in information from the brain, spinal cord, and sensory receptors from the rest of the body to output information about smooth, coordinated, timely movements. Ataxic CP is caused by damage to the cerebellum.

basal ganglia vmo.jpg

Basal Ganglia
The Basal Ganglia are a group of structures that regulate voluntary movement through a series of excitation and inhibition through their various connections. Ultimately their goal is to inhibit unwanted movements and facilitate the wanted, necessary movements. Both Athetoid and Dystonic CP are caused by damage to the basal ganglia.

Types of CP—Classification

Now that we know what areas of the brain are affected by CP, we can begin to understand the classification of this group of disorders. CP can be classified by severity level, topographical distribution of symptoms, or by motor function. For our purposes, classification by motor function is the most useful.
cp classification.jpg

  • Spastic (also called Pyramidal)
    • Spastic CP involves muscles continually contracting, resulting in stiff limbs, exaggerated reflexes, and resistance to stretching or relaxing.
  • Non-Spastic (also called Extrapyramidal)
    • Non-Spastic CP can be broken into two groups: dyskinetic and ataxic. Non-Spastic CP involves a fluctuation in muscle tone, with movements sometimes being involuntary with varying speeds, and sometimes a rhythmic nature.
      • Dyskinetic CP can be broken into two groups: athetoid and dystonic
        • Athetoid—involuntary movements in the arms, legs, and hands
        • Dystonic—affects postural muscles, leading to a twisted posture
      • Ataxic
        • Both balance and posture are affected, resulting in a wide and irregular gait. Also, impairment of fine motor skills, depth perception, and control of eye movements are all classified under ataxic CP symptoms.
  • Mixed (also called Unclassifiable)
    • Mixed CP simply refers to an unclassifiable set of symptoms that seem to fit both spastic and non-spastic types.

The following are images of the brains of children with different forms and severities of CP. In light of what has been presented in this page, nteresting images are "severe" in image B, as that child has preventricular leukomalacia. Also, images C and D show basal ganglia impairment, indicative of either Athetoid or Dystonic CP and image E has cortical damage, indicating Spastic CP.

cp brain images.png

Inputs and Outputs
Cerebral Palsy is usually seen as more of a problem with outputs than inputs. Generally there isn’t an issue with information being conducted toward the brain from the spinal cord, but with information being sent out from the brain. Regarding Spastic CP, which involves upper motor neuron damage, the output deficit is from the affected upper motor neurons, which affect the input to the putamen. In Spastic CP, all projections from the affected cortical neurons would be impaired, so input to the putamen would certainly not escape that fate. The main output issue with CP is the impaired or blocked transmission of information from the upper motor neurons, which would hinder the efficacy of the corticospinal tract. In Ataxic CP, the damaged cerebellum inadequately processes the input information from the rest of the brain and spinal cord and also does not send an appropriate response. In Dyskinetic CP (both Athetoid and Dystonic), the basal ganglia are impaired. Damaged input centers (striatum and subthalamic nucleus) result in improper outputs to the output centers (substantia nigra and globus pallidus). Each of these different subtypes of CP can range from mild to severe, depending on the extent of the damage and how much it affects these inputs and outputs.

Case Study
The following video is of a 20 year old patient who was diagnosed at age 3 with a mild case of Ataxic CP. The patient was born somewhere between three and four months premature with a birth weight less than two pounds, making him too small to get an adequate first breath of air. As a result, he has generalized underdevelopment of his brain from missing his third trimester and generalized damage to brain tissue from that critical moment where he lacked oxygen. To this day, the patient still presents with a slightly awkward gait pattern, lagging coordination of arm swing when walking, general balance challenges, poor fine motor control (especially seen in handwriting), slightly impaired speech (a condition called cluttering), the learning disability ADHD, mild mental retardation, and microcephaly. Things to notice in this video are the slight wobble from side to side as the patient walks back and forth across the floor to get the seed packets. This is due to minor damage in postural control, affecting trunk rotation. Also, when the patient walks, he exhibits a slight bounce due to heel cord tightness, a manifestation of slight spasticity. The patient exhibits fairly good balance moving forward, but the deficit is seen when walking backwards. The patient also has general good balance in standing on one foot and holding his arms out straight; patients with a more severe case would not be as controlled in these exercises. The patient's parents have also stated that when he was first diagnosed his physical symptoms of the disorder were much more noticeable and over time they have become more muted.


Cerebral Palsy is a group of congenital disorders that can affect both voluntary and involuntary movement depending on where the brain damage is located. Patients experience a wide array of symptoms as a result of this brain damage; likewise, they also experience different levels of severity. There is no cure for CP, but current research in this field has been on how to prevent CP and how to improve the lives of the children who are born with it, either through physical therapy or by creating more effective assistive devices. There may never be a cure for this disorder, but many patients still enjoy life even with these limitations.


This wiki space is dedicated to my younger brother, who is also the case study patient in the video above. Without his help, I would never have begun to understand Cerebral Palsy.

Suggested Readings

This article is about possible physical therapy programs for children with CP to take advantage of what motor skill they do have.
Damiano, D., Alter, K., Chambers, H. (2009). New Clinical and Research Trends in Lower Extremity Management for Ambulatory Children with Cerebral Palsy. Physical Medicine and Rehabilitation Clinics of North America. 20(3). Retrieved from

This article is an in-depth look at how gestational age affects the likelihood of CP in children.
Moster, D., Wilcox, A., Vollset, S., Markestad, T., Lie, R. (2010). Cerebral Palsy Among Term and Postterm Births. JAMA. 304(9). Retrieved from

This article contains information about motor function and motor development in children with CP regarding severity level.
Rosenbaum, P., Walter, S., Hanna, S., Palisano, R., Russell, D., Raina, P., …Galuppi, B. (2002). Prognosis for Gross Motor Function in Cerebral Palsy: Creation of Motor Development Curves. JAMA. 288(11). Retrieved from


  1. Ancel, P., Livinec, F., Larroque, B., Marret, S., Arnaud, C., Pierrat, V.,…Kaminski, M. (2006). Cerebral Palsy Among Very Preterm Children in Relation to Gestational Age and Neonatal Ultrasound Abnormalities: The EPIPAGE Cohort Study. Pediatrics. 117(3). Retrieved from
  2. Bax, M., Tydeman, C., Flodmark, O. (2006). Clinical and MRI Correlates of Cerebral Palsy: : The European Cerebral Palsy Study. JAMA. 296(13). Retrieved from
  3. Jones, M., Morgan, E., Shelton, J., Thorogood, C. (2007). Cerebral Palsy: Introduction and Diagnosis (Part 1). Journal of Pediatric Health Care. 21(3). Retrieved from
  4. Kuban, K.C.K., Allred, E.N., O’Shea, M., Paneth, N., Pagano, M., Leviton, A. (2008). An Algorithm for Identifying and Classifying Cerebral Palsy in Young Children. The Journal of Pediatrics. 153(4). Retrieved from
  5. Novak, I., Hines, M., Goldsmith, S., Barclay, R. (2012). Clinical Prognostic Messages from a Systematic Review on Cerebral Palsy. Pediatrics. 130 (5). Retrieved from
  6. O’Shea, T. M. (2008). Diagnosis, Treatment, and Prevention of Cerebral Palsy in Near-Term/Term Infants. Clinical Obstetrics and Gynecology. 51(4). Retreived from
  7. Pakula, A. T., Van Naarden Braun, K., Yeargin-Allsopp, M. (2009). Cerebral palsy: Classification and Epidemiology. Physical Medicine and Rehabilitation Clinics of North America, 20(3). Retrieved from

  1. Abdel-Hamid, H., Cerebral Palsy. Medscape Reference. Retrieved December 23, 2012, from
  2. Stern, K. (2012). My Child: The Ultimate Resource for Everything Cerebral Palsy. Retrieved December 23, 2012, from

  1. Boyd, D., & Bee, H. (2012) The Developing Child (13th ed). Boston, MA: Pearson.
  2. Saladin, K. (2009) Anatomy and Physiology: The Unity of Form and Function (5th ed). Boston, MA: McGraw Hill Higher Education.
  3. Purves, D. (2007) Neuroscience (4th ed). Sunderland, MA: Sinauer Associates, Inc.