improve postural stability by increasing the amount of time
a child practices correct postural control. Bertoti and
Gross23 used a biofeedback seat insert to improve erect
sitting posture in children with CP. Subjective assessment
by the therapist reported increased ability to achieve erect
posture without undesirable postural deviations. However,
internal and external validity of the study were threatened.
A small sample (n 5) was used which increases the standard
error and sample variability. Also, only children with
CP of “normal intelligence” were included, limiting applicability
of the results to the general CP population. Uncertainty
exists regarding the amount of daily use needed to
optimize gains, feasibility of adherence, and long-term
effects.