The purpose of the study was to evaluate the use of the
BBS to assess the balance abilities of children with cerebral
palsy. When the children were classified using medical
diagnostic categories, the ability to use scores on the
GMFM to distinguish among groups of children with differing
balance abilities was slightly better than that of
scores on the BBS, showing one more significant pair-wise
difference. This difference was between the children with
spastic diplegia who ambulated without aids and the children
with no motor impairment (Fig. 2). When functional
classification was used to categorize the children, the ability
to use scores on both tests to distinguish among the
groups improved and was identical. These results suggest
that both test characteristics and the method of classification
influenced the ability to use the tests to distinguish
among groups of children with different balance abilities.
When using diagnostic classification, the ability to use
scores on the GMFM to distinguish among the groups was
greater than when using scores on the BBS. This result was
most likely because the GMFM has more items at a higher
level of difficulty than the BBS. For example, there are more
items in Dimension E of the GMFM that require single-leg
stance, such as hopping on one leg in a circle. Administration
of these items distinguished between the balance abilities
of children with no motor impairment and children
with spastic diplegia who did not use aids to ambulate. The
most challenging items on the BBS include such items as
reaching forward with an outstretched arm (No. 8), turning
in a full circle in both directions (No. 11), alternately