Validity and reliability of the Repetitive Movement Test (RMT) in children with spastic Cerebral Palsy scheduled for ITB treatment

A common treatment for children with moderate to severe spasticity is therapy
using Intrathecal Baclofen. Several clinical assessment instruments are used to
measure the effect of ITB on spasticity, however, these tests are found to be
subjective, ordinal and of low resolution while standardizing is lacking. Since
several complications are reported for ITB treatment, an objective and valid
instrument to measure the effect of spasticity and pump function is necessary.
The repetitive movement test (RMT) is a relatively new measure developed and
used at our department to measure spasticity, raised tonus and range of motion.
While the RMT is found to be a valid and objective tool to measure the effect
of ITB on spasticity in spastic adults, the validity has yet to be established
in children with CP scheduled for ITB, the majority of the population seen at
the department for ITB test treatment. In addition, knowledge about the
reliability of the measurements would attribute to the clinical interpretation
of the results and usage of the RMT to check on pump function.

Primary objective is to assess the reliability and assess the reliability and
construct validity of the Repetitive Movement Test (RMT) as a measure of
spasticity in children with CP scheduled for ITB treatment, between 6-18 year.

This study is an observational cohort study. During baseline measurements,
which are pre-treatment, 3 measurements will be performed by examiner 1 and one
measurement by examiner 2, to assess the inter- and intra-reliability of the
RMT. In addition, a post-treatment test will be performed by examiner 1 on the
same test-day after administration of a test ITB doses, to assess the validity.
Current clinical spasticity assessment (SPAT) will also be performed to
correlate to the RMT results.

The burden is minimal, because the protocol runs in parallel to existing
clinical practice and will not affect clinical decision making, so no extra
visits are required. The measurements are passive and require the subject to
relax. They do not last longer than 30 seconds and the whole protocol not
longer than half an hour. The risks are minimal, because the measurements are
non-invasive, painless and easy to perform. The measurements are already
performed in clinical practice, but extra measurements are required to
structural measure the validitiy and reliability.
The result will not directly benefit the participant, but they will contribute
detection of pump dysfunction.
The study is focused on children with CP scheduled for ITB treatment, since
they compromise the majority of the patient population starting with ITB
treatment and will thus benefit from improved measurement of the effect of ITB
on spasticity and detection of dysfunctioning pumps.