01 Definition Se qxd

achieving any voluntary control of movement. The GMFCS has

now become the principal way to describe the severity of

motor disability for children with CP. The system has had good

uptake internationally and across the spectrum of health care

professions for use in research and clinical practice by provid-

ing a system for clearly communicating about children’s gross

motor function (Morris and Bartlett 2004). 

From 2000

Following a survey of practice across the continent, the group

for the Surveillance of Cerebral Palsy in Europe (SCPE) pub-

lished their standardized procedures for ascertaining and

describing children with CP for registers and databases

(SCPE 2000). The definition was largely a reiteration of that

proposed by Mutch and colleagues (Mutch et al. 1992) and

included five key points. CP is: (1) an umbrella term; (2) is

permanent but not unchanging; (3) involves a disorder of

movement and/or posture and of motor function; (4) is due

to a non-progressive interference, lesion, or abnormality;

and (5) the interference, lesion, or abnormality is in the

immature brain.

The system adopted by SCPE provides a decision flow chart

to aid classification into neurological and topographical cat-

egories including spastic (unilateral or bilateral), ataxic, dys-

kinetic (dystonic or choreo-athetotic), or not classifiable. Clearly

defined symptoms and requirements are provided for each

neurological category. Despite careful planning of the sys-

tem, there has been little work to demonstrate the validity

and reliability of classification. The lack of any defined crite-

ria for recording functional limitations in the SCPE definition

was noted by Lenski et al. (2001). Subsequently, SCPE, along

with other research groups, demonstrated that the inclusion

of a description of functional ability markedly improved the

reliability of diagnosing children with CP (Paneth et al. 2003).

Consistent application of the diagnosis is of paramount

importance when the prevalence of CP from different

sources and places is being compared. 

There has also been further progress in classifying children’s

motor abilities. The Manual Ability Classification System (MACS)

now provides a method analogous to the GMFCS for classify-

ing the ability of children with CP to handle objects (Eliasson

et al. 2006). The Functional Mobility Scale (FMS) has been

devised as an evaluative system to measure changes in walk-

ing ability, such as might be seen following intervention

(Graham 2004). The FMS enables a child’s performance over

three distances (5, 50, and 500 metres) to be classified by

their need for assistive devices such as a wheelchair or walk-

ing aid. In contrast to the GMFCS, where a child’s level

would not be expected to change, significant changes in FMS

levels have been observed following orthopaedic surgery.

This joins the battery of outcome measures to evaluate treat-

ment for children with CP such as the Gross Motor Function

Measure (Russell et al. 2003).

With rapidly improving imaging technology there is renewed

interest in aetiological classification systems correlating clin-

ical syndromes and neuroanatomy, challenging Freud’s 100-

year-old statement that this task was futile. Progress has been

made using ultrasound and magnetic resonance imaging

(MRI) to detect structural impairments of the brain before

they manifest as movement disorders (Accardo et al. 2004).

MRI can also be used to approximate the timing at which the

brain was damaged, based on normal neurodevelopmental

stages (Barkovich 2002, Krägeloh-Mann 2004). Only partial-

ly explained to date, Krägeloh-Mann (2004) summarizes

some of the correlations that are emerging between the tim-

ing and location of the lesion and functional, cognitive, and

sensory impairments.

The search for a single internationally accepted definition

of CP continues. Another international multidisciplinary

group met in 2004 and some of those participants then

revised the oft-cited definition by Bax (1964) to recognize

that the key motor deficit is often accompanied by other neu-

rodevelopmental impairments. Their new definition is:

Cerebral palsy describes a group of permanent disorders of the

development of movement and posture, causing activity limitation,

that are attributed to non-progressive disturbances that occurred

in the developing fetal or infant brain. The motor disorders of CP

are often accompanied by disturbances of sensation, perception,

cognition, communication, behaviour, by epilepsy and by secondary

musculoskeletal problems. (Modified after Bax et al. 2005)

Whilst welcoming the debate and the desire for consen-

sus, the new definition received mixed reviews in the accom-

panying editorials. Carr (2005) described how the proposed

definition and classification would affect clinical practice and

the challenge of shifting from traditional modes of thinking;

Blair and Love (2005) considered the precision of the definition

to be flawed in the same way as previous attempts, particularly

from an epidemiological perspective. Chiefly, they point out that

the term ‘non-progressive’ was no more clearly defined than

before, neither were the age limits and lower limit of severity for

inclusion, or what syndromes should specifically be excluded.

However, Blair and Love did not themselves provide any sug-

gestions of how to address these issues. Whilst the precision

with which the definition is applied by clinicians may have neg-

ligible consequences for treatment, the implications for mea-

suring rates of CP over time are more profound. 

So, in summary, after more than 150 years of debate we do

not yet have a universally accepted definition of CP; nor do we

have an agreed method for classifying the impairment that

has been shown to be robust in terms of validity and reliabili-

ty. It would be ungracious, however, not to pay a respectful

tribute to those illustrious and often remarkable people who

have all in their own way strived to further the scientific study

of CP. In contrast, there has been more progress in classifying

children’s movement and manual abilities as these are proba-

bly easier to observe and categorize. The GMFCS has been

adopted widely to classify movement ability and perhaps

demonstrates that testing the fundamental properties of the

validity and reliability of classification systems vastly

enhances their credibility. To move the scientific study of CP

forward we now need to examine how well the recent defini-

tions and classifications proposed by SCPE and Bax’s group

actually perform in practice.

Acknowledgements

The author is grateful to Peter Rosenbaum, Jennifer Kurinczuk, and

Ray Fitzpatrick, and also the anonymous peer reviewer, for their

comments on previous versions of the manuscript.

References

Accardo J, Kammann H, Hoon AH Jr. (2004) Neuroimaging in

cerebral palsy. Journal of Pediatrics 145: S19–27. 

American Academy for Cerebral Palsy and Developmental Medicine

(2005) Mission. Available at www.aacpdm.org/index?service=

page/mission. Accessed 20th July 2006.

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Definition and Classification of CP

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