Types of Cerebral Palsy

Cerebral palsy (CP) is a motor disorder often caused by an injury to the parts of the brain that control movement. This condition is nonprogressive, which means it will not change as the person ages.

Everyone’s cerebral palsy can look different. CP can affect muscle tone, certain limbs, and communication ability. The severity can vary widely among individuals.

Cerebral palsy is usually described as one of four types: 

1. spastic cerebral palsy
2. ataxic cerebral palsy
3. athetoid or dyskinetic cerebral palsy
4. mixed cerebral palsy

These categories are based on the person’s muscle tone and the location of the brain injury. Several classification systems can describe someone’s cerebral palsy in more detail, like how much of the body CP affects or how much movement ability is impacted.

Because cerebral palsy is different for every individual, there are many ways to classify its severity. These categories help physicians diagnose cerebral palsy and determine what someone needs in regards to treatment, therapy, or care.

Cerebral palsy severity can be classified by the following: 

• Limb Involvement: how many and which limbs are affected
• Muscle tone: hypertonic, hypotonic, or mixed
• GMFCS (Gross Motor Function Classification System): levels of severity based on movement ability, functional ability, and reliance on assistive technology
• MACS (Manual Ability Classification System) – describes ability to manipulate things with one’s hands
• CFCS (Communication Function Classification System) – describes severity of communication ability

Cerebral palsy is usually labelled as spastic, ataxic, athetoid/dyskinetic, or mixed. 

Spastic cerebral palsy is by far the most common type of cerebral palsy, comprising roughly 80% of all cases. 

Children with spastic cerebral palsy have an injury in the upper motor neurons of the central nervous system. Spastic CP causes the muscles to be very tight and stiff, a condition known as hypertonia. Additional side effects of spastic cerebral palsy include joint deformities, scoliosis, hip dislocation, and more.

A person with spastic cerebral palsy typically has a “scissor gait,” which means that their knees and thighs may cross or touch while walking, and they may be crouched and walk on their tip toes.

Ataxic cerebral palsy is the least common type, occurring in roughly 5-10% of all CP cases. 

Damage to the cerebellum can cause ataxic CP. Ataxic cerebral palsy mainly causes problems with balance, coordination, and fine motor skills. The child may have hypotonia and tremors. Someone with ataxic CP may have problems with balance and coordination (particularly while walking) and precise movements such as writing. It also is common for people with this type of cerebral palsy to have trouble seeing (depth perception and eye movement control), hearing, or speech.

In young children, hypotonia is a common manifestation of ataxic CP. Unlike the rare form of degenerative neurological disease ataxia, ataxic cerebral palsy is a non-progressive condition. 

Athetoid/dyskinetic cerebral palsy (ADCP) makes up 15-20% of CP cases. 

This subtype is the result of damage to the basal ganglia, the part of the brain responsible for regulating voluntary movements. In many cases, ADCP is caused by hypoxic-ischemic encephalopathy/HIE (brain damage due to a lack of oxygenated blood) or kernicterus (brain damage due to severe or improperly-managed jaundice).

Athetoid/dyskinetic cerebral palsy causes movements to be slow and writhing or fast and jerky. People with ADCP have mixed muscle tone. ADCP causes a combination of hypertonia (stiffness), hypotonia (limpness), and involuntary motions. Children with ADCP may have trouble sitting upright, walking, grasping objects, performing fine motor tasks, sucking, swallowing, and talking.

Mixed cerebral palsy involves a combination of symptoms that don’t all fit within a single subtype of CP. For example, a child may have both hypertonia and hypotonia. In other words, some of their muscles are too tight, while others are too loose.

This classification system categorizes by how many and which limbs cerebral palsy affects.

Cerebral palsy may be described based on how muscle tone is impaired. Typically, this refers to hypertonic or hypotonic muscle.

Hypertonia refers to high muscle tone. Hypertonic muscles are stiff and rigid. Normally, muscles work in pairs; one muscle group contracts while the other relaxes. Hypertonic muscles all become active at the same time. This causes the person to have jerky movements and muscle spasms. The person may clench their fists, point their toes, or walk with a scissor gait (legs crossed).

Hypertonia is abnormally low muscle tone. Hypotonic muscles are limp, floppy, and relaxed. Someone with hypotonic muscles may have tremors or struggle with balance and coordination. Their muscles may be too loose to hold posture, and they can struggle to control eye and mouth movements.

The Gross Motor Function Classification System (GMFCS) is a system that is used to classify infants, children, and adolescents with cerebral palsy into five groups based on the extent of movement impairment, age, and functional performance. 

• Level 1: Movement is mildly affected, but the child can walk at home and places out of the home. They can climb stairs, run, and jump. However, they may struggle with balance, coordination, and speed.
• Level 2: The child can walk in most environments, but have difficulty with long distances, balancing on difficult terrain, or in crowds. They may need to use a railing to climb stairs or rely on a cane or other mobility device for extended outings.
• Level 3: The child commonly uses a mobility device like a walker at home and out of the home. They may need a wheeled mobility device for long distances. 
• Level 4: The child needs a mobility device pushed by someone or a powered mobility device in most situations. At home, they may walk for short periods or with help. 
• Level 5: The child’s movement is extremely limited. They need someone else to move a wheelchair for them. They may struggle to hold their head or torso upright and may not be able to control leg and arm movements.

The Manual Ability Classification System (MACS) categorizes cerebral palsy based on an individual’s ability to manipulate objects with their hands, which is closely tied to one’s ability to complete tasks independently. The MACS is applicable to children ages 4-18.

The Communication Function Classification System (CFCS) categorizes individuals with cerebral palsy and other disabilities based on everyday communication performance. As with the GMFCS and the MACS, the CFCS has five levels that represent increasing severity.

• CFCS Level I: The person can effectively send and receive communicative information with unfamiliar and familiar partners.
• CFCS Level II: The person effectively, but slowly, sends and receives communicative information with both unfamiliar and familiar partners.
• CFCS Level III: The person is usually able to effectively send and receive communication information with familiar partners, but may struggle to communicate with unfamiliar partners.
• CFCS Level IV: The person inconsistently sends and receives communication information with familiar partners, and rarely can communicate with unfamiliar partners.
• CFCS Level V: The person rarely communicates effectively, even with familiar people.