Clinical features

Individuals with cerebral palsy experience one or more of the following clinical features:

Abnormal muscle tone

Tension or resistance in a muscle that is outside the normal range

• Hypertonia is muscle tone that is higher than normal.
  • Spasticity refers to a velocity-dependent increase in muscle tone. The majority of people with cerebral palsy have spasticity in one or more muscles. The effect of spasticity on movement changes with posture, position or effort. Moderate to severe spasticity may hinder movement and function and can contribute to joint contractures.
  • Clonus is an abnormal reflex response that results in an involuntary, rhythmic muscle contraction (like a spasm)
  • Rigidity refers to stiff or inflexible muscles. Rigidity is a common feature in cerebral palsy caused by anoxia, such as in near drowning. Muscles that have rigidity feel heavy and are difficult to move.
• Hypotonia is muscle tone that is lower than normal. This results in muscles that feel "floppy" or weak. Hypotonia may be seen in young infants with cerebral palsy, with spasticity or hypertonia manifesting as the child develops.

Contracture

When a joint, such as an elbow or knee, cannot move through its normal range of motion, it is said to have a contracture. Spasticity can cause muscles to be tight and develop contractures. Contractures may limit a person’s ability to sit in chair, stand up straight or open a hand.

Involuntary movements (dyskinesia)

• Dystonia is a movement disorder in which involuntary sustained or intermittent muscle contractions cause twisting and repetitive movements, abnormal postures, or both. Dystonia can occur in the eyes, mouth neck, trunk arms or legs and may interfere significantly with functional activities such as sitting, walking, or reaching. 
• Athetosis is slow, continuous, involuntary non-rhythmic movement that interferes with postural stability. It often occurs with chorea, and is called choreo-athetosis.
• Chorea is an ongoing random-appearing sequence of one or more discrete involuntary movements or movement fragments.

Weakness

Muscle weakness is common in cerebral palsy but is not always easily detected. Spasticity may mask weakness, making it difficult to fully assess. Weakness may be present in conjunction with spasticity and may manifest itself in gait deviations or difficulty performing activities of daily living.

Impaired motor control

This is the inability to recruit muscles with normal precision, speed or timing. When this ability is impaired, movement occurs synergistically. Synergistic movement is when motion at one joint, such as the ankle, cannot occur without movement at another joint, such as the knee. Impaired motor control may interfere with functions such as walking or holding a pencil.

Poor balance

Balance is coordination of sensory input and controlled, purposeful motor output. Falling may be the result of poor control of posture, the inability to move in response to surroundings or it may be caused by tripping over a foot that gets in the way.

Gastro-intestinal and nutritional problems

These may include problems with eating, chewing, swallowing or drooling.

Problems with vision and perception

Visual acuity, or the clarity of vision, may be unaffected in cerebral palsy. Problems with perceptions, or interpreting what is seen, include discriminating contrast, depth perception or identifying shapes.