A randomized, controlled, and evaluator-blinded trial will be carried out to investigate the effects of 8 weeks of upper limb somatosensory discrimination therapy compared to an equal dose of motor therapy on sensorimotor outcomes in children and adolescents with spastic unilateral cerebral palsy aged 7 to 15 years old. Additionally, the potential role of clinical and neurological baseline characteristics on treatment response will be explored, including the extent of the brain lesion, age and baseline somatosensory function. The researchers primarily expect that the bimanual performance will improve equally in children and adolescents from both intervention groups, as measured immediately after the intervention has ended. The researchers hypothesize, however, that there will be a better retention effect in children and adolescents that received somatosensory discrimination therapy, resulting in differences between both groups in bimanual performance as measured at 6-months follow-up. The researchers further expect larger improvements in somatosensory function for children and adolescents in the somatosensory discrimination group and this both immediately after the intervention and at 6-month follow-up.

BACKGROUND: Although cerebral palsy has primarily been defined as a motor disorder, research has shown that up to 90% of children and adolescents with unilateral cerebral palsy also present with somatosensory deficits in the upper limb. Despite the fact that somatosensation has shown to be crucial for coordinated movements and even motor learning, therapy programs designated to improve somatosensory deficits is scarce. Nevertheless, previous studies provided a neurological basis for somatosensory interventions in individuals with unilateral cerebral palsy, showing that the somatosensory system is disorganized and potentially treatment responsive. Hence, a clinical reasoning framework for somatosensory interventions was recently developed. Somatosensory discrimination therapy, also known as Sense for Kids therapy, was one of the recommended approaches. This therapy was found to improve tactile perception in chronic stroke patients. Also in children and adolescents with unilateral cerebral palsy, a first study reported promising results to improve functional hand use as well as somatosensory function. Yet, the full clinical potential and long-term effects of this therapy still remain to be explored.

AIM: The aim of this study is to investigate the effects of Sense for Kids therapy compared to an equal dose of motor therapy on upper limb sensorimotor outcomes in children and adolescents with unilateral cerebral palsy. Additionally the potential role of clinical and neurological baseline characteristics on treatment response will be explored, including the anatomical characterization of the brain lesion, age and baseline somatosensory function.

METHODS/DESIGN: A randomized, controlled, and evaluator-blinded randomized controlled trial will be carried out in 50 children and adolescents with spastic unilateral cerebral palsy aged between 7 and 15 years old. To determine the number of required participants, a sample size calculation was performed for the primary research objective, being better bimanual performance at 6 months follow-up for children and adolescents that received Sense for Kids therapy compared to upper limb motor therapy. An effect size of 0.9 was calculated based on the results of earlier studies on intensive upper limb therapy in children with unilateral cerebral palsy. Combined with an alpha-level of 0.05 and a statistical power of 0.80, this results in a required sample size of 21 children and adolescents in each group to detect a difference equal or larger than the smallest detectable difference between groups. This number will be increased to 25 participants per group to account for inevitable dropouts and to maximize the study sample for prediction purposes.

Participants will be randomized to the intervention or active control group through randomization by minimization with an allocation ratio of 1:1. Participants will be stratified based on age (2 levels: <11 years and ≥11 years), manual ability (3 Manual Ability Classification Scale: I, II and III) and tactile impairment (2 levels: mild or moderate-severe). The probability will be set at 80% to diminish allocation prediction. Participants in both groups will receive three session of 45 minutes upper limb therapy per week for a period of 8 weeks, resulting in a total therapy intensity of 18 hours. The intervention group will receive Sense for Kids therapy, which consists of component-based training and occupation-based training. During the component-based training participants will perform graded and structured practice of tactile object recognition, texture discrimination and proprioception. During the occupation-based practice, participants will repetitively perform self-chosen activities of daily living while attention is denoted to somatosensory aspects necessary for successful task completion (e.g., position of the upper limb, texture of materials, localization of materials based on touch). Participants in the control group will receive an equal amount of motor training, consisting of unimanual motor tasks and bimanual goal directed training of self-chosen activities.

Outcomes will be assessed at three different points in time, being within two weeks prior to therapy commencement (baseline), within one week following therapy completion (post-intervention) and 6 months after the therapy has ended (follow-up). Outcome assessments include qualitative and quantitative measures of upper limb sensorimotor function. The primary outcome measure is the Assisting Hand Assessment and is used to score the (spontaneous) use of the more impaired hand during bimanual activities. The medical imaging protocol, which will be only acquired at baseline, includes structural Magnetic Resonance Imaging and diffusion weighted images.

The time effects of the intervention on upper limb sensorimotor outcomes will be objectified using linear and/or generalized mixed models. Behavioral and neurological variables will further be included in the model as covariates to study their predictive value on the therapy response.

Inclusion Criteria:

1. Congenital or acquired, predominantly spastic unilateral cerebral palsy;
2. Aged 7 to 15 years;
3. Minimal ability to actively grasp and hold an object (modified House Functional Classification System ≥4);
4. Having a confirmed impairment in tactile function as objectified using a clinical assessment battery containing assessments of tactile registration and tactile perception; and
5. Sufficient cooperation to comprehend and complete the test and therapy procedures;

Exclusion Criteria:

1. Botulinum toxin-A injections six months prior to testing;
2. A history of upper limb surgery one year prior to testing;
3. Severe comorbidities hindering test assessments (e.g., severe cognitive problems); and
4. Inability to communicate in Dutch.

The assessments of sensorimotor upper limb function at all three time points will be performed by a blinded assessor who is not involved in the conception of the study or the provision of therapy to the participants. Assessments that were video-recorded (Assisting Hand Assessment and Goal Attainment Scaling) will be scored afterwards by another evaluator who will be blinded to group allocation and time point of assessment. Since the robotic measurements and three-dimensional motion analysis are fully automated, these assessments will be performed by a physiotherapist not blinded to group allocation. Participants and parents will be blinded to the study hypotheses. The treating therapists will not be blinded to group allocation.