psychosocial scores in this sample were only slightly lower
than the normative sample, a difference that is statistically
significant, but may not be clinically important.
This study represents one of very few examinations of
the stability of CHQ scores longitudinally. In analyzing
group results, children did not change significantly over
time on Physical summary scores of the CHQ. Psychosocial
summary scores changed significantly over the study period
of 18 months, but these changes were small and not likely
to be of substantial clinical importance. Vargus-Adams [22]
also found no significant changes in CHQ physical HRQoL
for children with cerebral palsy over a one-year time period.
In a sample of children with juvenile rheumatoid arthritis
and juvenile spondyloarthropathy, Selvaag et al. [24] recorded
significant improvements in health related quality
of life, except for pain, over a 3-year period. These findings
may be different because they are the result of an arthritis
intervention study rather than an examination of naturalistic
stability. The sample in this current study has predominantly
central nervous system-based physical disabilities so it
is not surprising that the results are more similar to the
findings of Vargus-Adams [22].
These findings are similar to other studies that have
explored quality-of-life measurement in children and youth
with disabilities [26,45]. This result may reflect the complexity
of the children's condition and their typical association
with additional health or development conditions
such as problems with vision, hearing, or cognition. The
presence of several health or development conditions can
have a greater impact on the family and is often associated
with lower physical functioning. Thus, there can be considerable
variability across children with similar primary
health conditions. This finding may also reflect the complexity
of quality-of-life and the lack of direct explanatory
relationships between quality-of-life scores and child and
youth functioning [46]. As well, the role of health interventions
received during the study timeframe was not
examined. Change in health status may be more likely in
children with a less complex health condition with fewer
associated neurological problems [24].
Although there was little average change in CHQ Physical
summary scores, there is evidence of heterogeneity and
less stability among children. The presence of heterogeneity
in slopes (steepness of change over time) and intercepts
(time 1 scores) was tested in level-1 model and those findings
led to level-2 model analyses to identify characteristics
that explained these variances. Findings indicate that
heterogeneity of individual trajectories for Physical scores
within this sample is explained by presence of environmental
barriers, impact on family, child’s behavior and child’s
physical functioning. While environmental barriers and
behavior had a negative influence, physical functioning had
a positive influence. In planning programs and services,
these factors can be taken into account and potentially