Sakzewski et al. reply

Abstract

SIR–We would like to thank Dr Basu and Professor Eyre for their comments regarding our randomized clinical trial comparing equal doses of modified constraint-induced movement therapy (mCIMT) and bimanual training in school-aged children with unilateral cerebral palsy.1, 2 The primary concern proposed is the potential that constraint of the unimpaired hand used in mCIMT may have a deleterious impact on functioning of that hand, and that for many children with unilateral cerebral palsy, the unimpaired hand may also have subtle difficulties.3 We agree with Basu and Eyre that the unimpaired upper limb needs to be considered and may not be truly ‘unimpaired’. Our findings in a previous cross-sectional study which included all baseline data of children in the randomized trial confirmed a modest reduction in stereognosis ability for the unimpaired upper limb, although this may reflect developmental progression as all of the children who had difficulties were under the age of 8 years. We also found that movement efficiency of the unimpaired upper limb, (measured on the Jebsen Taylor Test of Hand Function [JTTHF]), was more than two standard deviations below published norms for 68% of the group. It is important to note in a small group of typically developing children, 47% also scored greater than one standard deviation below published norms.4 This certainly highlights the need to re-evaluate normative data for the JTTHF which is now nearly 40 years old. The question of whether constraining the unimpaired hand would have a deleterious effect on that limb was a consideration in our study. We sought to measure movement efficiency (JTTHF), grip strength, and sensation (stereognosis and moving two-point discrimination) on the unimpaired upper limb at baseline and each follow-up. In the process of preparing this reply, we found an error in Table I in the original paper regarding the 3-week follow-up score on the JTTHF for the mCIMT group. We would like to clarify these results. Data for the JTTHF, stereognosis and moving two-point discrimination were highly skewed so that non-parametric Mann–Whitney U tests were used to determine whether follow-up scores were significantly different from baseline. Generalized estimating equations were used to determine within group changes for grip strength between baseline and each follow-up. Our results for the unimpaired limb before and after each intervention are summarized in Table I in this letter. Our results demonstrate that movement efficiency on the unimpaired upper limb was not compromised following mCIMT, and over time, children in the mCIMT group were significantly faster at 26 weeks compared to baseline. The small two-second increase in median time from baseline to 3-weeks follow-up for the mCIMT group was non-significant. Similarly, there was no deleterious effect on grip strength, with both groups demonstrating significant improvement between baseline and 26 weeks. There was no change in stereognosis or moving two-point discrimination for the mCIMT group, confirming no deleterious effects from wearing the glove for 60 hours over 10 days. One important caveat to emphasis is that this study used a modified version of CIMT. Studies of adults following stroke and a small number in children used a full arm cast that was worn continuously over a 21-day period, with maximal restraint of the unimpaired limb.5 Our protocol was different in that children wore a mitt on their unimpaired upper limb for 6 hours a day during the program (total dose 60h), allowing free use of their limb throughout the remainder of the day. The mitt itself restricted manipulation but allowed continued use of the impaired upper limb for propping and stabilizing in bimanual tasks. We would like to emphasize that the use of a rigid hand glove changed the role of the unimpaired hand for support/stabilizing in tasks, allowing/forcing the impaired hand to act as the dominant hand in manipulation tasks. We feel confident that this mCIMT protocol did not adversely impact on function of the unimpaired upper limb in this group of school-aged children with unilateral cerebral palsy (aged 5–15y). In addition, our neuroscience results from this study have also confirmed that there were no negative effects on motor evoked potentials for the unimpaired hand after 60 hours of mCIMT in our intensive block of therapy. Both groups demonstrated no changes in motor evoked potentials for the unimpaired hand from baseline after either treatment using transcranial magnetic stimulation performed by an assessor masked to group allocation.6 Whether CIMT or mCIMT may have a deleterious effect on performance of the unimpaired hand and brain reorganization in much younger infants (<3y) requires further careful evaluation.