1. A report: the definition
and classification
of cerebral palsy
April 2006
ReportExecutiveCommittee:
Peter Rosenbaum (DefinitionPanelChair) MD,CanChfld
Centre forChildhood DisabilityResearch,Hamilton,Ontario,
Canada.
Nigel Paneth (ClassificationPanelChair)MD, Department of
Epidemiology,MichiganStateUniversity,East Lansing,MI, USA.
Alan LevitonMD,Neuroepidemiology Unit,Children’s
Hospital,Boston, MA, USA.
Murray Goldstein*(Co-Chair)DO,MPH, United CerebralPalsy
Research& EducationalFoundation,WashingtonDC, USA.
Martin Bax (Co-Chair)DM,FRCP,Divisionof Paediatrics,
Obstetricsand Gynaecology,Imperial College,London,UK.
PanelConsultants:
Diane Damiano PhDPT,Washington UniversityDepartment of
Neurology,St.Louis,MO, USA.
Bernard Dan MD, PhD,H6pital Universitairedes Enfants,
ReineFabiola,UniversiteLibrede Bruxelles,Brussels,Belgium.
Bo Jacobsson MD, PhD,PerinatalCenter, Sahlgrenska
University Hospital East,Goteborg, Sweden.
*Correspondence to MurrayGoldstein, UCP Researchand
EducationalFoundation; Suite 700,1660L Street Nvz:
Washington, DC, USA 20036.
For a variety of reasons,the definitionand the clawificationof
cerebralpalsy (CP) need tobe reconsidered.Modern brain
imagingtechniqueshave shed new light on the nature of the
underlyingbrain injuryand studieson the neurobiologyof and
pathology associatedwith brain developmenthave further
exploredetiologic mechanisms.It isnow recognizedthat
assessingthe extentof activityrestriction ispart of CP
evaluationand that people without activityrestrictionshould
not be includedin the CPrubric. Also,previousdefinitionshave
not given sufficientprominence to the non-motor
neurodevelopmentaldisabilitiesof performanceand behaviour
that commonly accompanyCP, nor tothe progressionof
musculoskeletaldifficultiesthat oftenoccurs with advancing
age. In order to explore this information,pertinent material was
reviewedon July 11-13,2004at aninternational workshopin
Bethesda,MD (USA)organizedby anExecutiveCommittee and
participatedin by selected leadersin the preclinicaland clinical
sciences. At the workshop,it was agreedthat the concept
‘cerebralpalsy’ shouldbe retained. Suggestionsweremade
about the contentof a revised definitionand classificationof CP
that would meet the needsof clinicians,investigators,health
officials, familiesand the public and would provide a common
languagefor improved communication.Panels organizedby the
ExecutiveCommittee used this informationand additional
commentsfromthe international communityto generate a
reportonthe Definitionand Classificationof CerebralPalsy,
April 2006.TheExecutiveCommitteepresentsthis report with
the intent of providinga commonconceptualizationof CPfor
use by a broad international audience.
Cerebral palsy (CP) isawell-recognizedneurodevelopmental
condition beginningin earlychildhood and persistingthrough
the lifespan. Originallyreported by Little in 1861(and origi-
nally called‘cerebralparesis’),CPhasbeen thesubjectofbooks
and papers by some of the most eminent medical minds of
the past one hundred years. At the end of the 19th century,
SigmundFreud and SirWilliam Oslerboth begantocontribute
important perspectiveson the condition. From the mid-l940s,
the founding fathers of the American Academy for Cerebral
Palsyand DevelopmentalMedicine (Carlson,Crothers,Deaver,
Fay, Perlstein,and Phelps) in the United States,and MacKeith,
Polani, Baxand Ingramof the LittleClubinthe United Kingdom,
wereamong the leaderswhomovedthe concepts and descrip-
tions of CPforward and caused this condition to become the
focusof treatment services,advocacy, and research efforts.
It has alwaysbeen achallenge to define ‘cerebralpalsy’,as
documented by the numberof attempts that havebeen made
over the years. For example, Mac Keith and Polani (1959)
defined CP as ‘a persisting but not unchanging disorder of
movement and posture, appearing in the early years of life
and due to a non-progressive disorderof the brain, the result
of interferenceduring its development.’In 1964,Bax report-
ed and annotateda definition of CPsuggested by an interna-
tional working group that has become a classic and is still
used. It stated that CP is ‘a disorder of movement and pos-
ture due to adefect or lesion of the immature brain.’Though
this brief sentenceis usuallyall that is cited by authors,addi-
tional comments were added by Bax: ‘Forpractical purposes
it is usual to exclude from cerebral palsy those disorders of
posture and movementwhichare (1)ofshort duration,(2)due
to progressivedisease,or (3) due solelyto mental deficiency.’
Thegroupforwhich Baxwasthe reporterfeltthat this simple
sentence could be readily translated into other languages
and hoped that it might be universallyaccepted.At that time,
it was felt that it was wiser not to define precisely what they
meant by ‘immaturebrain’, asanysuch definition might limit
services to those in need. Like its predecessors, this formula-
tion of the CP concept placed an exclusive focus on motor
aspects,and alsostressed the specificconsequences of earlyas
opposed tolate-acquiredbrain damage.Not formallyincluded
in the conceptwere sensory,cognitive,behavioral and other
associated impairments very prevalent in people with ‘disor-
dered movement and posture due to adefect or lesion of the
immature brain’, and often significantlydisabling.
The heterogeneity of disorders covered by the term CP,as
well as advances in understanding of development in infants
with earlybrain damage, led Mutch and colleagues to modify
the definition of CP in 1992 as follows: ‘an umbrella term
covering a group of non-progressive, but often changing,
motor impairment syndromessecondary to lesions or anom-
aliesof the brain arising in the early stages of development.’
Thisdefinitioncontinued to emphasizethe motor impairment
and acknowledgeditsvariability,previouslyunderscored in the
MacKeith and Polani definition; it also excluded progressive
disease, a point introducedin Bax’sannotation.
8 Definition and Classification of CP

2. In response to the emerging need to evaluate the status of
information about cerebral palsy and revisit the language
presently used to describe it, an International Workshop on
Definition and Classification of Cerebral Palsy was held in
Bethesda,Maryland (USA), onJuly 11-13 2004, co-sponsored
by United CerebralPalsy Research and EducationalFoundation
in theUSAandtheCastangFoundationinthe United Kingdom:
support was provided by the National Institutes of Health/
National Institute of Neurological Disorders and Stroke and
the Dana Foundation. The task of the participants (listingfol-
lows) was to revisit and update the definition and classifica-
tion of cerebral palsy in light of emerging understanding of
developmental neurobiology and changing concepts about
impairments, functional status and personal ‘participation’.
Reassessmentof the definition of CPwas prompted by a host
of factors:changes in deliveryof care to children with disabil-
ities;recognition that childrenwithslowlyprogressiveinborn
errors of metabolism can present with motor difficultiesat
times indistinguishable from those of children with nonpro-
gressive disease; increased availabilityof high-qualitybrain
imagingto identifyimpairments in brain structure; acknowl-
edgment that developmental motor impairment is almost
invariably associated with a range of other disabilities; and
increased understanding about associated antecedents and
correlates of CP
The Workshop participants agreed that CP as conceptual-
ized previouslyhad proved tobe a usefulnosologicconstruct,
but that previousdefinitionshad become unsatisfactory.They
underlined that CP is not an etiologicdiagnosis,but aclinical
descriptiveterm.Reservationswere expressedabout theexclu-
sivefocuson motordeficit,giventhat persons with neurode-
velopmental disabilitiesoften present impairments of awide
range of functionsthat may or may not include severe motor
manifestations,thereby callingfor the need of an individual-
ized, multidimensional approach to each affected person’s
functional status and needs. However,it was suggested that
the concept‘cerebralpalsy’be retainedto serve diagnos-
tic, management, epidemiologic, public heath, and research
purposes. It was felt that an updated definition of CP, taking
into account recent advances in the understanding of the
physiology of and pathology associated with brain develop-
ment, aswell aschangesin terminology,should be developed
for international use. The updated definition needed to
meet the requirements associated with these purposes, as
well as to enhance communication among clinicians,scien-
tists and the public.As in the prior concept, itwasagreed that
the motordisorderneededto be emphasized;however,
recognitionshouldbe providedthat otherdevelopmen-
tal disorders of performance and behaviour can and
often do accompanyit. This emphasis on the motor disor-
der is stipulated in that children with CP most often present
for medicalattention because of motor abnormalities,even if
theyhave other developmentalproblems.
To underline the idea that a comprehensive approach to
CP needs to be multidimensional and that management of
patients with CP almost always requires a multidisciplinary
setting,classesofdisorders commonlyaccompanyingCP have
been identified and included in the revised definition. This
addition reflects the concept that CP is one group of neu-
rodevelopmental disorders which involve numerous devel-
oping functions. As in other neurodevelopmental disorders,
various manifestations of the disordered brain may appear
more significantindifferentpersons or atdifferentlifeperiods,
e.g.someaspectsof the motor impairment,sensoryloss,intel-
lectualdisability,attentionaldifficulty,epilepsy,musculoskeletal
dysfunctionand manyothers maybe more prominent or more
problematic at different stagesof the life of a person with CP
References
1.Freud S. (1897) Die infantileCerebrallahmung. In: NothnagelH,
editor.SpecieIIePathoIogieund Therapie,Bd IX,Teil 111.Vienna:
Holder.p 1-327.
2. OslerW (1899) 7&eCerebralPalsies ofChildren.A CIinicaIStudy
for thelnffrmaryfor NervousDiseases. Philadelphia:Blakiston.
3. LittleClub. (1959) Memorandum on terminology and
classificationof ‘cerebralpalsy’.(MacKeith R, et al., editors)
CerebPalsyBull 1:27-35.
4. Bax MCO. (1964)Terminologyand classificationof cerebral palsy.
Dev Med ChiIdNeurol6:295-307.
5.Mutch LW AlbermanE. HagbergB, Kodama K, VelickovicMV
(1992)Cerebral palsyepidemiology:where are we now and
where are we going?DevMed ChildNeuroI 34: 547-555.
What follows is: The Defrnition and C1assifiwion of
Cerebral Palsv.A o d 2006, an annotatedexplanationof
the terms used, and the thinking behind the choice of
thosewords.Thismaterial was authored by the members of
the ExecutiveCommitteefunctioning in panels enriched with
expertise fromconsultants and by comments and suggestions
from many reviewers responding to drafts provided to the
international community. The Definition and Classification
of Cerebral Palsy,April 2006document is offered for interna-
tional consensus and adoption,with the intent of providing a
broad spectrum of audiences with a commonconceptualiza-
tion about cerebral palsy.
I. Definition of cerebral palsy
Cerebralpalsy (CP) descri&esagroup ofpetmanentdis-
orders of the development of movement and posture,
causing activity limitation, that are attri&uted to non-
progressive disturbances that occurred in the develop
ingfetal orinfantbrain. TEwmotor d i s o r hofcerebral
palsy are oflen accompanied by disturbances of sensa-
tion,perception, cognition, communication, and bebav-
but; by epilepsy, and by secondary musculoskeletal
p r o b h .
ANNOI’ATION
Cerebralpalsy(CP)’describesagroup20fpermanent3disorders*
of the development5 of movement and posture6 causing’
activity limitation,nthat are attributed to9 non-progressive10
disturbances” that occurred in the developingfetalorinfant12
brain.l3 Themotor disorders ofcerebralpalsyare oftenaccom-
panied byI4disturbances of ~ensation,’~perception16,cogni-
tion,” communication, and behaviour, by epilepsy20,and by
secondary musculoskeletal problems.21
COMMENTARY O N THE TERMS AND CONCEPTS
It is hoped this annotation of the definition willclarifythe CP
concept and allow unified use of the term both within and
across the concerned fields.As it relies essentiallyon clinical
aspects and does not require sophisticated technology, it
should be possible to applythis definition very widely.
1.‘Cerebralpalsy (CP)’-It isgenerally agreed that the CP
concept,essentiallya clinical formulation based on phenome-
nology,remainsuseful in the current stateof nosology,insofar
Definitionand Classificationof CPApril 2006 PeterRosenbaumet aI. 9

3. as the term describes a prevalent, clinically important and
identifiablegroup of persons with neurodevelopmental dis-
abilities.Although the word ‘palsy’has become largelyobso-
lete in medicalnosography and has no univocalconnotation,
the term ‘cerebralpalsy’is established in the literature and
is used universallyby clinicians,therapists, epidemiologists,
researchers, policymakers,health care funding organization
andlaypersons.Theterm ‘CPhas,however,beenvariablyused,
with poor comparability across different places and times,
indicating the need for an internationally acceptable defini-
tion. The term cerebral palsy (CP) hasbeen retained to relate
future research in CPtoexistingpublished 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 termsof aetiologyaswell as in types
and severity of impairments. Severalgroupings are possible
and warranted to serve different purposes. These groupings
may show overlap. Therefore, the singular form ‘CP’is used
(asopposed to ‘cerebralpalsies’).
3. ‘permanent’- This definition excludes transient disor-
ders, but recognizes that children and adults have changing
patterns of clinicalmanifestations.
4. ‘disorders’-This refers to conditions in which there is
disruptionof the usualorderlyprocessesof childdevelopment.
5. ‘development’- The notion of alteration in children’s
earlydevelopmentisessentialtothe CPconcept.It distinguish-
esCPErom phenotypicallysimilardisorders in children due to
later-acquired lesions, at a time when basic motor develop-
ment isrelativelywell established.The ‘developmental’aspect
of CP is also important with regard to management strategies
that may includeinterventionsthat addressthe developmental
consequences of the functionallimitationsassociatedwith CP,
aswellasinterventionsthat aredirected at the underlyingneu-
robiological processes. The developmental nature of CP
almost always implies impactson the developmental trajecto-
riesof the people who have CI?Themotor impairmentsof chil-
dren eventuallydiagnosedwith CP begin to manifestvery early
in child development, usually before 18months of age, with
delayedoraberrant motor progress;otherneurodevelopmen-
tal and functionaldBiculties that often accompanythe motor
signs can appear throughout childhood or later. The clinical
picture of CPevolves with time,development,learning,activi-
ties,therapies,ageing,and otherfactors.
6.‘movementandposture’-Abnormal grossand finemotor
functioning and organization (reflecting abnormal motor
control) are the core features of CF! These motor problems
can lead todifficultieswithwalking,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
movementandpostureare not consideredtohave CR
7. ‘causing’-Activity limitationsare presumed tobe acon-
sequence ofthe motor disorder.Thus,disorders of movement
and posture that are not associated with activity limitations
are not considered part of the CPgroup.
8. ‘activity limitation’-The World Health Organization’s
(WHO) International Classificationof Functioning, Disability
and Healthspeaksof ‘activity’as “...theexecution of a task or
action by an individual”,and identifies ‘activitylimitation’as
“...difficultiesan individualmay have in executing activities”.
Thisterm amplifiesthe previousWHOconcept 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-functionalconnections 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 palsyremains 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
discreteseriesof eventswhich are no longer active at the time
of diagnosis.This incitingevent@)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
disordersis not consideredCP.
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)
impairmentof the brain.In a proportion ofcases it iscurrently
not possible to identify a specific ‘disturbance’or a specific
timingof the events that appearto impacton maturation.
12.‘fetalor infant’-The specification‘fetalorinfant’reflects
the idea that disturbances that occur very earlyin human bio-
logical development impact differentlyon the development
of motor function than disturbances that occur later, even
those that occur in earlychildhood.There is no explicitupper
age limit specified,although the firsttwoor three years of life
are most important in the timingof disturbances resulting in
CF!In practicalterms, disturbance resultingin CP ispresumed
to occur before the affected function has developed (e.g.
walking,manipulation, etc.).
13.‘brain’-The term ‘brain’includesthecerebrum,thecere-
bellumand the brain stem.It excludes motor disorders solely
of spinal,peripheral nerve, muscular or mechanical origin.
14.‘accompaniedby’-In addition to the disorder of move-
ment and posture, people with CPoften showotherneurode-
velopmentaldisorders or impairments.
15.‘sensation’-Vision, hearing and other sensory modal-
ities may be affected, both as a function of the ‘primary’dis-
turbance@) 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 globaland specificcognitiveprocess-
es may be affected,including attention, both as a function of
the ‘primary’disturbance@)to which CP is attributed and as
a secondary consequence of activity limitations that restrict
learning and perceptual development experiences. A child
who hasseverelyimpairedcognitionandnomotorsigns
10 Definition and Classification of CP

4. (exceptperhapsfor some degreeof hypotonicity)is not
includedw i t h the conceptof CF?
18. ‘communication’-Expressiveand/or receptivecommu-
nicationand/or socialinteraction skillsmay be affected,both
asafunctionofthe ‘primary’disturbance@)towhichCPisattrib-
uted, and asasecondaryconsequenceof activitylimitationsthat
restrict learning and perceptual developmentexperiences.
19. ‘behaviour’-This includes psychiatricor behavioural
problems such as autistic spectrum disorders, ADHD, sleep
disturbances, mood disorders and anxietydisorders.
20. ‘epilepsy’-Virtuallyeveryseizuretypeand manyepilep-
tic syndromes maybe seen in persons with CI?
21. ‘secondarymusculoskeletal problems’ - People with
CP may develop a variety of musculoskeletal problems, such
as muscle/tendon contractures, bony torsion, hip displace-
ment, spinal deformity. Many of these problems develop
throughout life and are related to physical growth, muscle
spasticity,ageingand otherfactors.
References
1.World Health Organization.(2001)International Classification
ofFunctioning,Disability andHealth(ICF). Geneva:World
Health Organization.
acollaboration ofcerebralpalsy surveysand registers.DevMed
ChildNeurol 4 2 8 1 6 8 2 4 .
3. NlNDS Workshopon Classificationand Definition of Disorders
CausingHypertoniainChildhood.(2001)http:/hwvminds.nih.gov/
news-and-events/Hypertonia- Meeting-2001. htm
4.World Health Organization.(1980)InternationalClassification
ofImpairment,Activity and Participation -ICIDH-2.Geneva:
World Health Organization.
5.Palisano R, RosenbaumP, WalterS, et al. (1997)Developmentand
reliabilityof asystemto classifygross motor function in children
with cerebral palsy.Dev Med ChildNeurol39:214-223.
6.Beckung E, Hagberg G . (2002)Neuroimpairments, activity
limitations,and participationrestrictionsin children with
cerebralpalsy.DevMed ChildNeurol44:309-3 16.
7.EliassonAC, Rosblad B, Krumlinde-SundholmL, Beckung E,
ArnerM, OhrwallA-M, RosenbaumP: (2006)ManualAbility
Classification System(MACS) forchildrenwithcerebralpalsy:scale
developmentand evidenceofvalidity and reliability.DevMed
ChildNeuroI 48: 549-554.
8.Banlett DJ, Purdie B. (2005)Testing ofthe SpinalAlignmentand
Rangeof MotionMeasure:adiscriminativemeasure ofposture
and flexibility for childrenwith cerebralpalsy.DevMedChild
NeuroI47: 739-743.
9.GortermRosenbaumPL, HannaSE,Palisano RJ, Bartlett DJ,
Russell DJ,WalterSD, Raina P, GaluppiBE, Wood E. (2004)Limb
distribution,type of motordisorder and functional classification
ofcerebralpalsy:howdo theyrelate?Dev Med ChildNeurol
46:4 6 1 4 6 7 .
2.CansC. (2000)Surveillanceof Cerebral Palsyin Europe:
10.Ashwal S, Russman BS, BlascoPA, et al.(2004)Practice
parameter:diagnostic assessmentofthe childwith cerebral
palsy:reportofthe QualityStandardsSubcommittee of the
AmericanAcademyof Neurology andthe Practice Committee of
the Child Neurology Society.Neurology 62:851-863.
11. Classificationof cerebralpalsy
Cerebralpalsy (CP)describesagroupof permanent disorders
of the development of movement and posture,causing activ-
ity limitation, that are attributed to non-progressive distur-
bances that occurred in the developing fetal or infant brain.
Themotor disordersof cerebral palsyare often accompanied
by disturbances of sensation, perception, cognition, commu-
nication and behaviour,by epilepsy,and by secondarymuscu-
loskeletalproblems.
The above definition of cerebral palsy covers a wide
range of clinical presentations and degrees of activity
Wtation. It is therefore useful to further categorize
individualswithCP into classesorgroups.Thepurposes
of classificationinclude:
1.Description: providing alevelof detailabout an individ-
ual with CP that will clearlydelineate the nature of the prob-
lem and itsseverity.
2. Prediction:providinginformationthat can informhealth-
care professionals of the current and future service needs of
individualswith CI?
3.Comparison: providing sufficientinformation to permit
reasonable comparison of series of cases of CP assembled in
different places.
4. Evaluation of change: providing information that will
allowcomparison of the same individualwith CP at different
points in time.
Traditionalclassificationschemeshave focused principally
on the distributional pattern of affectedlimbs ( e g ,hemiple-
gia,diplegia)with an added modifierdescribing the predom-
inant type of tone or movement abnormality (e.g.,spastic,
dyskinetic).However,it has become apparent that additional
characteristics must be taken account of for a classification
schemeto contribute substantivelyto the understanding and
management of this disorder.
INFORMATION REQUIRED FOR CLASSIFICATION
The information available to provide an adequate classifica-
tion of the features of CP in any individual will vary over the
age span and across geographic regions and settings. The
role of aging in changing the clinical phenomenology of CP
has been little studied, and the possibility of classification
changes over time cannot be completely dismissed. Defining
the presence or degree of accompanying impairments, such
ascognitivedeficits,is age-dependent,and inyoung children
the typeof motor disordermay be hard to characterize. Some
young children diagnosed as having CP may in fact have as
yet undiagnosed neurological disorders that are very slowly
progressive.While progressive disorders are not included in
the CPrubricbydefinition,aperiod of observationthat includes
serial examinations of the child may at times be needed
before their exclusion can be assured.
Factors other than age will affect classification.Historical
data, especially about the course of pregnancy, will vary in
reliability and validity. Where neuroimaging facilities, diag-
nostic specialistsand biochemical laboratories are not avail-
able, it may not be possible to completelyexclude progressive
disorders and underlying pathology, as described by neu-
roimaging and other laboratory findings, However, all clas-
sification documentation should include the age of the
child,the natureof theinformationavailablefrom clini-
cal history (e.g. whether from clinical notes, maternal
recall or period of observation of the child), and the
extent to which metabolic and neuroimaginginvestiga-
tionhasbeen performed.
L:SES AND LIMITATIONS O F A CLASSIFICATION SYSTEM
Classificationoften requires makingdifficultdecisions about
where to draw the boundaries within ordinal or quantitative
measures.Somedegreeofarbitrarinessisinevitable.Assignment
of individuals with the diagnosis of CP to distinct clinical
groups is not straightforward, and will differ depending on
thecharacteristic(s)chosenasthebasisforclassification.No one
Definition and Classificationof CPApril 2006 PelerRosenbaurn el a/. 1 1

5. singleapproach has emerged as definitive.Depending on the
purpose of the classification, certain characteristics or com-
binations of characteristicsmay be more useful than others.
For example,in assessingthe effectivenessof a new treatment
for aspecific typeof tone abnormality,the nature of the motor
disorder and the levelof functional motor abilityare likelyto
be paramount, while determining servicedeliveryneeds will
require consideration of accompanyingimpairments.
No classificationsystemis useful unlessit is reliable.
Thus it is not enough to specifythe characteristicstobe used
in classification;they must be operationally defined so that,
in general, competent examiners will classify the same indi-
vidualin the samewaygivenidentical information. Providing
such definitions is, however,beyond the scope of this docu-
ment. For example, the term 'spastic diplegia' is problematic
because its existing definitions are variable and imprecise,
and because evidence is lacking that the term can be used
reliably. Some use the term to describe children with spastic
CPwhoseonlymotor deficitisinthe legs,whileothers include
children who have arm involvement of lesser severity than
leg involvement. However, determining the relative severity
of arm and leg involvement can be challenging since they
performverydifferentfunctions.Discontlnuationoftheterm
'spasticdiplegia'isrecommended;however, if the term is
used, the user should define exactlywhat is meant, and what
characteristicsthe term describes.
TableI Componentsof CP classification
1.Motorabnormalities
A. NATUREAND TYPOLOGYOFTHE MOTOR DISORDER The
observedtonal abnormalitiesassessed onexamination(e.g.
classificationlisted in Table I is recommended.Each is
elaborated upon in the text that follows.
1.Motorabnormalities
l.A. NATUREANDTYPOLOGYOFTHE MOTOR DISORDER
The type of abnormal muscle tone or involuntary movement
disorderobservedorelicitedisusually assumedto be relatedto
the underlying pathophysiologyof thedisorder,and may also
reflect etiologiccircumstances, as in kernicterus. Individuals
with cerebral palsy have traditionally been grouped by the
predominant type of motor disorder with a 'mixed' category
available in those cases when no one type dominates. This
strategyhasbeen adoptedby theclassificationsystemdescribed
in the Reference and Training Manual of the Surveillanceof
Cerebral Palsy in Europe (SCPE),'which dividesCP intothree
groupingsbasedon the predominant neuromotor abnormality
-spastic, dyskinetic or ataxic,with dyskinesiafurther differ-
entiated intodystonia and choreoathetosis.
However, an argument can be made that many children
have mixed presentations, and that identifyingthe presence
of each of the tone and or movement abnormalities may be
of greater clinical and etiologic utility, as recommended by
the 2001 NINDS workshop on childhood hypertonia." It is
recommendedthat casescontinueto be classifledby the
dominant type of tone or movement abnormality,cate-
gorized asspasticity,dystonia,choreoathetosis, orataxia,but
that any additional tone or movement abnormalities present
should be listed assecondarytypes. The term 'mixed' should
not be used without elaboration of the component motor
disorders. For a recent review of the terminology of motor
disorders, see Sangeret al.Lii.iv
hypertonia,hypotonia)aswell as the diagnosed movement
disorderspresent,such asspasticity,ataxia,dystonia,athetosis.
B. FUNCTIONALMOTORABILITIES: The extent to which the
individualis limited in hisorhermotorfunction,including
l.B. FUNCTIONALMOTORABILITIES
TheWHOInternationalClassificationof Functioning,Disability
and Health (ICF),"alongwithseveralotherrecent publications,-
orornotorandspeech function.
The presenceor absenceoflater-developingmusculoskeletal
problemsand/oraccompanyingnon-motorneurodevelopmental
o r sensoryproblems,suchas seizures,hearingorvision
impairments,or attentional,behavioral,communicativeand/or
cognitivedeficits,and the extent to whichimpairmentsinteractin
individualswithcerebralpalsy.
A.ANATOMICDISTRIBUTION:Thepartsofthe body(limbs,trunk,
bulbarregion,etc.)affectedby motor impairmentsor limitations.
B. NEURO-IMAGINGFINDINGS:TheneuroanatomicfindingsonCT
orMRI imaging,such asventricularenlargement,white matter
lossor brainanomaly.
4. Causationand timing
Whetherthere is aclearlyidentifiedcause, as is usuallythe case
with post-natalCP (e.g.meningitis,head injury)orwhen brain
malformationsare present,andthe presumedtime frameduring
which the injuryoccurred,ifknown.
2.Accompanyingimpairments
3.Anatomical and neuro-imagingfindings
DEVELOPMENT OF A STANDARDIZED CLASSIFICATION SCHEME
Thestateof the scienceunderlyingthe proposed classification
has evolved in recent years and continues to progress at a
rapid pace, particularlyin the area of quantitative assessment
of the neuro-imaging and clinicalfeatures of cerebral palsy.
Theseadvanceswill continue to improveour abilityto classlfy
children and adults with cerebral palsy more accurately. For
classificationof CP,use of the fourmajordimensionsof
have sensitized health professionals to the importance of
evaluating the functional consequences of different health
states. The functional consequences of involvement of
the upperandlowerextremitiesshouldthereforebe sep
arately classified using objective functional scales. For
the key function of ambulation, the Gross Motor Function
Classification System (GMFCS) has been widely employed
internationally to group individuals with CP into one of five
levels based on functional mobility or activity limitation." A
parallelclassificationscale,the BimanualFine MotorFunction
Scale,orBFMF,hasbeen developedforassessingupper extrem-
ity function in cerebral palsy, but has not been as extensively
studied as the GMFCS.ViiA newer instrument for assessing
hand andarmfunction- theManualAbilityClassificationSystem
or MACS-has been shownto havegood inter-rater reliability
between parents and professionals, and will shortly be pub-
lished.""' Concurring with SCPE, it is recommended that a
functional classification system be applied to hand and arm
function in children with CE Bulbar and oromotor difficul-
tiesare common in cerebral palsy and canproduce important
activitylimitation,but there is asyet noactivitylimitationscale
forsuch functions.Ahigh research priorityis the development
of a scaleforspeech and pharyngealactivitylimitationin cere-
bral palsy. In the meantime, the presence and severityof bul-
bar and oromotorinvolvementshould be recorded.
While activity limitation is important, the extent to which
motor disorders affect the ability to participate in desired
12 DefinitionandClassification of CP

6. societal roles is also an essential consideration. However,at
present,evaluationof participationrestriction (formerlytermed
“handicap”)in CP is not well developed, and reliable catego-
rization of children based on this aspect of daily life is there-
fore not yet possible.
2.Accompanying impairments
In many individualswith cerebral palsy, other impairments
interfere with the ability to function in daily life, and may at
timesproduce evengreater activity limitation than the motor
impairments that are the hallmark of cerebral palsy. These
impairments may have resulted from the same or similar
pathophysiologic processes that led to the motor disorder,
but they nonethelessrequire separate enumeration.Examples
include seizure disorders, hearing and visual problems, cog-
nitiveand attentionaldeficits,emotionaland behavioralissues,
andlater-developingmusculoskeletalproblems.Theseimpair-
ments should be classified as present or absent, and if pre-
sent, the extent to which they interfere with the individual’s
abilityto function or participate in desired activitiesand roles
should be described. In concurrence with the SCPE recom-
mendation, the presenceorabsenceof epilepsy(defined
astwoormoreafebde,non-neonatalseizures)be record-
ed, and IQ, hearingand vision be assessed.While SCPE
providesterminologyfor describing different degrees of cog-
nitive,hearingandvisualimpairment,theIQscore,corrected
visionineacheye,anddecibelloss(ifany)ineachearbe
recordedwheneverthisinformationisavailable.Standardized
instruments are availableto measure IQ,vision and hearing,
and categories describing specificlevelsof dysfunction (e.g.,
visualimpairment,profound hearing loss,mild mental retar-
dation*) havecome to be generallyaccepted.
3.Anatomicaland neuro-imagingfindings
3A. ANATOMICDISTFUBUTION
Thepattern andextentof the motordisorder inCPwith respect
to different anatomical areas should be specified. Previous
classification schemes included only the extremities and
required a subjectivecomparison of severityin the arms and
the legs.Theinherent validityof makingthis comparison has
been questioned since the arms and legs are so structurally
andfunctionallydiverse.Notablymissingfromcurrent anatom-
ical classification schemes is description of truncal and bul-
bar involvement.AU bodyregions-trunk,eachlimb,and
oropharyx-need to be describedindividuallyin terms
of anyimpairmentsof movement or posture.A scale for
describingtruncal posture in cerebral palsy has recentlybeen
developed.’”Separate objective classification schemes have
alsobeen developed for the upper and lower extremities.
It isacknowledgedthat the terms “diplegia”and “quadriple-
gia”have been extensivelyused for determining the anatomic
distribution of the motor disorder and have become firmly
entrenched in research and clinicalpractice, The severity of
involvement in the arms (ranging from ‘none’ to ‘lessthat
that of the legs’)has been used as the main characteristic for
makingthis distinction which is problematic asstated above.
Gorter et al. have documented the imprecision of these
terms in clinical practice.x It is recommended that the
termsdiplegiaandquadriplegianot be used until more
preciseterminologyevolvesandgainssimilaracceptance.
*UK usage: learning disabilities.
~ ~ ~ ~~~
Those who continue to use these terms should define
exactlywhat is meant by them and the characteristics
the termsdescribe.
A promising alternative approach that has been rec-
ommended,andwhichis beingutilizedcurrentlyby the
SCPE,is the differentiationof unilateralversusbilateral
motorinvolvement.Categorizationbased on thisdistinction
has shown good reliability(SCPEmanual’). Even this distinc-
tion can still be blurred since many children with primarily
unilateral CP may also have some degree of motor involve-
ment on the oppositeside and some children with primarily
bilateralinvolvementmayhave appreciable asymmetryacross
sides.Thisdistinction should be considered aspart of a mul-
tiaxialclassificationscheme, thus it should be coupled with a
description of the motor disorderand functional motor clas-
sificationin both upper and lower extremities.
3.B. NEURO-IMAGING FINDINGS
Untilrecently,correlationsbetween neuroimagingfindingsand
clinicalpresentation in cerebral palsy were weak. However,
advancesboth in imaging technologyand inquantitativemotor
assessments are changing this picture. The goal of categoriz-
ing all patients based on specificneuroimaging findings will
require more development before implementation.Therec-
ommendation of the American Academy of Neurology
to obtain neuroimaging flndings on all children with
cerebral palsy should be followed whenever feasible.”
At present, information is insufficientto recommend anyspe-
cificclassificationscheme for neuroimaging findings.
4. Causeand timing
It is increasinglyapparentthat cerebralpalsymay result from
the interaction of multiple risk factors, and in many cases,
no identifiable cause may be found. Therefore, while every
reasonable effortshould be undertaken to investigatecauses
or causal pathways, clear-cut categorizationby cause is
unrealistic at the present time. It is possible that by look-
ing further downstream from putative cause to common
mechanisms of injury, and by grouping cases on that basis,
a more salient method of classification may be developed.
For the present, timing of insult should only be noted
when reasonably firm evidence indicates that the
causativeagent,oramajorcomponentofthecause,was
operativein a specilk time-window,as for example,with
post-natal meningitis in a previously well infant. While
recording adverse events in the prenatal, perinatal and post-
natal life of a child with CP is necessary, clinicians should
avoid making the assumption that the presence of such
events is sufficient to permit an etiologic classification that
implies a causal role for these events in the genesis of CP
in the affected individual.
References
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acollaboration of cerebral palsy surveysand registers.
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news-and-events/Hypertonia_Meeting_2001 .htm
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(2003)Task Force on Childhood Motor Disorders:Classification
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14 Definition and Classification of CP