Development and

Development andreliability of a system,
to classiffy gross motor
function in children
with cerebral palsy
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To addressthe need for a standardized system to classifs the
gross motor functionof childrenwith cerebralpalsy, the
authorsdevelopeda 5vvelevelclassification system analogous
to the staging and grading systemsusedin medicine.
Nominal group process and Delphi surveyconsensusmethods
were used to examine content validits and revise the
classificationsystem until consensusamong 48experts
(physicaltherapists,occupationaltherapists,and
developmental pediatricianswith expertisein cerebralpalsy1
was achieved.Interrater reliability (K) was 0.55 for children
less than 2 yearsof age and 0.75 for children2 to 12years of
age. The classificationsystem has applicationfor clinical
practice,research,teaching,and administration.
‘(‘erebra1palsy‘ irfcrs to a group of disorders in the tlevelop-
iiicliit of posttrire a i d motor contid. occui-i*ingas a result of a
noii-progressive lesion of the developing centrid ner\’ouss p -
ten1(Uns 1964).Thistletinition ent-ompassesa witle vaiiety of
pithological andclinical entities that have in common atlevel-
ol)inentaIiiiotoi-disorderthat can viwy in etiology, manifesta-
tions. stverit.y. prognosis. antl comorbitlities. Despite the best
efforts of I)rofcssionaIs.fi.oiii many disciplines, a gieat deal
iwntiins unknown about the naturd liistoiy of cerebral palsy.
It is iwognizetl that motor oiiteome is i.oughly ielatetl to
’severity’but to (late there has not been a genei*allyaccepted
stantlartlizetlsystem of classification of severity of motor tlis-
ability foruse in clinical practice antl research.
Methods of classification that have been proposed are
biisetl on ( a )pathophysiology or neui.oanatomicallocation of
‘tIwlesion (Fay IO:TO, Perlstein 1957,Minear IN6):(b)impair-
ments in iiiuyle tone. refles activity. and voluntary control of
movc~m(wt(Fay 1950, Perlstein 1952): (c) parts of the body
most involved (Balf and Ingram 1955, AIincar 1956): ((I)
ambulatory status(Ratlell-Ribcra 1985.Yokochi et HI. 1993),
tir (e) cl~grecof motor impailmcnt (e.g.‘mild’.‘moderate’.
’severe’)(Balf aiitl Ingrain 1955. hliiiear 1966,Yokoclii et al.
1!)!):3).‘I‘heseincthotls of classifiration rely heavily on clinical
j utlgment antl are primal-ilyof value fortliagnosis.Th(4r relia-
bility antl validity have not been investigated. Evans et al.
( 1989)tlevelopetl 11 recording forin to collect data on impair-
ment niid disability in children with neuroniotor dysfunction
for use in a register on childhood impairment. The form
indutles items to rate a rhiltl’s head control, trunk control,
gait ,‘andupper limb fnnction but does not inclutlc an o v e i d
classitication of motor ability.
\Ve have atloptd an alternative approach to classification,
basetI on the concepts oftIisabiIity and h!!ctiOnaI limitation.
The International Classification of Impairments, Disabilities,
and Hantlica~k(ICIDH) developed by the World Health
Organimtion ( 1980)defines disability as ‘the restriction or
ladr of ability to perform an activity in the manner or within
tlir range consicleirtl normal for a human being’.The concept
of functional limitation is includctl in the models of tlisable-
inent tlcvelol)etl by Sagi (1965)and the Sational Center for -
Jiedical Rehabilitation IkwwcIi in the United States( 1993).
Sagi defiiiecl functional limitation as a ‘limitation in perfor-
mance at the levelof the whole person’. We believethat classifi-
eation of children with cerebral palsy on the basis of abilities
antl limitations in gross motor function should eilliance com-
munication among ~irofessionalsantl families with respect to
( 1) tletcimining LI chiltl’sneeds antl making management dcci-
sions. (2)thecreation ofdatabases describingthedevelopment
of ehildien with cerebral palsy,and(3)comparingand general-
izing the results of program evaluations and research into the
outcome of treatment. Furthermore if the classification sys-
teni isfound to have predictivevalidity, early classification of a
child (e.g.at age2years)would help parents to anticipatetheir
cliiltl‘slater motor function.
The purposes of this study were (1) to construct a gross
motor function classification system forchildren with cerebral
palsy, annlogous to the staging antl grading systems used for
tumours, (2) to esamine content validity through nominal
groupprocessandDelphisurvey consensusmethods involving
tlevelopmental therapists and pediatricians with expertise in
cerebral palsy,and (3)to determine interrater reliability ofthe
classification system. We wanted a descriptive classification
.
systemthat \voultl be quick iintleasy to use.valid, and I-eliable.
Method
The Gross Motor Disability ('Iassification System was tlcvrl-
oped in four 1)hiiscs. First the autliors tlraftetl tlie system.
During phases two and tliive. the validity of ...