01 Definition Se qxd

as the term describes a prevalent, clinically important and

identifiable group of persons with neurodevelopmental dis-

abilities. Although the word ‘palsy’ has become largely obso-

lete in medical nosography and has no univocal connotation,

the term ‘cerebral palsy’ is established in the literature and

is used universally by clinicians, therapists, epidemiologists,

researchers, policy makers, health care funding organization

and lay persons. The term ‘CP’ has, however, been variably used,

with poor comparability across different places and times,

indicating the need for an internationally acceptable defini-

tion. The term cerebral palsy (CP) has been retained to relate

future research in CP to existing published work. 

The following explanations are offered to clarify several

aspects of the definition of CP:

2. ‘a group’ – There is general agreement that CP is a het-

erogeneous condition in terms of aetiology as well as in types

and severity of impairments. Several groupings are possible

and warranted to serve different purposes. These groupings

may show overlap. Therefore, the singular form ‘CP’ is used

(as opposed to ‘cerebral palsies’). 

3. ‘permanent’ – This definition excludes transient disor-

ders, but recognizes that children and adults have changing

patterns of clinical manifestations. 

4. ‘disorders’ – This refers to conditions in which there is

disruption of the usual orderly processes of child development.

5. ‘development’ – The notion of alteration in children’s

early development is essential to the CP concept. It distinguish-

es CP from phenotypically similar disorders in children due to

later-acquired lesions, at a time when basic motor develop-

ment is relatively well established. The ‘developmental’ aspect

of CP is also important with regard to management strategies

that may include interventions that address the developmental

consequences of the functional limitations associated with CP,

as well as interventions that are directed at the underlying neu-

robiological processes. The developmental nature of CP

almost always implies impacts on the developmental trajecto-

ries of the people who have CP. The motor impairments of chil-

dren eventually diagnosed with CP begin to manifest very early

in child development, usually before 18 months of age, with

delayed or aberrant motor progress; other neurodevelopmen-

tal and functional difficulties that often accompany the motor

signs can appear throughout childhood or later. The clinical

picture of CP evolves with time, development, learning, activi-

ties, therapies, ageing, and other factors.

6. ‘movement and posture’ – Abnormal gross and fine motor

functioning and organization (reflecting abnormal motor

control) are the core features of CP. These motor problems

can lead to difficulties with walking, feeding and swallowing,

coordinated eye movements, articulation of speech, and sec-

ondary problems with behaviour, musculoskeletal function,

and participation in society. However, people with neuro-

developmental disabilities that do not primarily affect

movement and posture are not considered to have CP.

7. ‘causing’ – Activity limitations are presumed to be a con-

sequence of the motor disorder. Thus, disorders of movement

and posture that are not associated with activity limitations

are not considered part of the CP group.

8. ‘activity limitation’ – The World Health Organization’s

(WHO) International Classification of Functioning, Disability

and Health speaks of ‘activity’ as “…the execution of a task or

action by an individual”, and identifies ‘activity limitation’ as

“…difficulties an individual may have in executing activities”.

This term amplifies the previous WHO concept of ‘disability’ to

recognize changing international concepts and terminology.

9. ‘attributed to’ – Understanding of developmental neu-

robiology (including genetic, biochemical, and other influ-

ences on brain development) is increasing rapidly, such that

it is becoming possible to identify structural and other evi-

dence of brain maldevelopment in people with CP. As a con-

sequence, structural-functional connections and correlations

are becoming more clearly delineated than has previously

been possible. It must, however, be acknowledged that at the

present time a full understanding of causal pathways and

mechanisms leading to cerebral palsy remains elusive.

10. ‘non-progressive’ – The term non-progressive is used

to denote that the pathophysiological mechanisms leading

to CP are presumed to arise from a single, inciting event or

discrete series of events which are no longer active at the time

of diagnosis. This inciting event(s) produce(s) a disruption of

normal brain structure and function which may be associated

with changing or additional manifestations over time when

superimposed on developmental processes. Motor dysfunc-

tion which results from recognized progressive brain

disorders is not considered CP. 

11. ‘disturbances’ – This term refers to processes or events

that in some way interrupt, damage or otherwise influence

the expected patterns of brain formation, development and

maturation, and result in permanent (but non-progressive)

impairment of the brain. In a proportion of cases it is currently

not possible to identify a specific ‘disturbance’ or a specific

timing of the events that appear to impact on maturation. 

12. ‘fetal or infant’– The specification ‘fetal or infant’ reflects

the idea that disturbances that occur very early in human bio-

logical development impact differently on the development

of motor function than disturbances that occur later, even

those that occur in early childhood. There is no explicit upper

age limit specified, although the first two or three years of life

are most important in the timing of disturbances resulting in

CP. In practical terms, disturbance resulting in CP is presumed

to occur before the affected function has developed (e.g.

walking, manipulation, etc.).

13. ‘brain’ – The term ‘brain’ includes the cerebrum, the cere-

bellum and the brain stem. It excludes motor disorders solely

of spinal, peripheral nerve, muscular or mechanical origin. 

14. ‘accompanied by’ – In addition to the disorder of move-

ment and posture, people with CP often show other neurode-

velopmental disorders or impairments.

15. ‘sensation’ – Vision, hearing and other sensory modal-

ities may be affected, both as a function of the ‘primary’ dis-

turbance(s) to which CP is attributed, and as a secondary

consequence of activity limitations that restrict learning and

perceptual development experiences.

16. ‘perception’ – The capacity to incorporate and inter-

pret sensory and/or cognitive information may be impaired

both as a function of the ‘primary’ disturbance(s) to which

CP is attributed, and as a secondary consequence of activity

limitations that restrict learning and perceptual develop-

ment experiences.

17. ‘cognition’ – Both global and specific cognitive process-

es may be affected, including attention, both as a function of

the ‘primary’ disturbance(s) to which CP is attributed and as

a secondary consequence of activity limitations that restrict

learning and perceptual development experiences. A child

who has severely impaired cognition and no motor signs

10

Definition and Classification of CP

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