Information for Parents of Children with Cerebral Palsy

Risk factors associated with cerebral palsy

A risk factor is not a cause; it is a variable which, when present, increases the chance of something occurring – in this case, cerebral palsy. Just because a risk factor is present does not mean cerebral palsy WILL occur; nor does the absence of a risk factor mean that cerebral palsy will NOT occur.

In a study in the US (3), a group of investigators found the following factors are associated with an increased risk of cerebral palsy:

·        Mother 40 years or older            

·        Mother under 20 years               

·        Father under 20 years              

·        First child or child born fifth or more

·        Child one of twins (particularly if one twin died)

·        Baby of low birth weight (less than 2.5 lbs)                  

·        Premature birth (less than 37 weeks)

More than one risk factor can be present at the same time (e.g. low birth weight and being a twin) and such a combination can further increase the probability of cerebral palsy occurring.
 

Types of cerebral palsy

Three different parts of the brain working together initiate and control the muscles that affect movement and posture. The part of the brain that is impaired determines how a person with cerebral palsy will be affected. There are three main types of cerebral palsy:

Spastic cerebral palsy (spasticity)

This is caused by impairment in the cerebral cortex (the outer layer) of the brain and is the most common form of cerebral palsy. It is characterised by constant increased muscle tone and weakness in the parts of the body affected. This increased muscle tone (hypertonia) creates tightness in the muscles, leading to a decreased range of movement in the joints. The effects may increase with anxiety or increased effort, leading to excessive fatigue.

Athetoid Cerebral Palsy or dyskinetic cerebral palsy (athetosis)

This is caused by impairment in the basal ganglia area of the brain. It is characterised by involuntary and uncontrollable muscle tone fluctuations, sometimes involving the whole body. The muscles alternate between being floppy and tense and there will often be difficulty in maintaining posture. The person usually has full range of movement in their joints, but not the stability or co-ordination to control their movements.

Unwanted movements may be small, rapid, irregularly repetitive, random, and jerky, sometimes referred to as choreic movements. The unwanted movements may also be of a long slow, writhing nature. Someone with athetosis will often appear restless and constantly moving, only being still when fully relaxed and sometimes only when asleep.

The movements will often become worse when the person is excited or is attempting to do something.

Speech is nearly always affected to some degree, because of difficulty in controlling the tongue, breathing and vocal chords. Similarly there may be difficulties with eating and, the person may drool (have saliva coming out of their mouth).

Ataxic cerebral palsy (ataxia)

This relatively rare form of cerebral palsy, which affects less than 10% of people with cerebral palsy, is caused by impairment to the cerebellum, which is in the base of the brain.

The cerebellum co-ordinates the actions of groups of muscles and is responsible for, amongst other things, balance. As with athetoid cerebral palsy, all four limbs and the trunk are usually involved.

This impairment can lead to a general poor sensation of balance, unsteadiness and staggering when walking. Tremors may also be present when the person is attempting a task.

It is, however, quite common to have a combination of two or more of the above types and so not fit neatly into any one category. This is usually described as “mixed cerebral palsy”. Examples of this are:

·        A child with spastic diplegia will have mostly spastic muscle difficulties, with the legs affected more than other parts of the body. However the child might also have some athetosis and balance problems.

·        A child with athetoid quadriplegia might have some ataxia and spasticity present as well.

Cerebral palsy can be categorised further, by referring to the parts of the body affected.

The three main categories are as follows:

·        Diplegia is where both legs are affected more than the hands and arms.

·        Hemiplegia occurs where one side of the body (including arm and leg) is affected.

·        Quadriplegia/Tetraplegia means that all four limbs are involved together with, usually, the trunk and neck.

Occasionally you may come across these categories:

·        Monoplegia – used when only one limb is involved.

·        Triplegia means that three limbs are affected - usually both legs and one arm.

However, you may find different categories may be used by different professionals.

For more information about cerebral palsy and Scope services

Contact Scope’s Cerebral Palsy Helpline for information, advice and support. Copies of all Scope’s information sheets can be downloaded from the website or obtained from the Helpline. Referrals to Scope’s Community Teams and services can be made through the Helpline.

Scope’s website address is www.scope.org.uk