Upper Limb Somatosensory Discrimination Therapy and Dose-matched Motor Therapy in Children and Adolescents With Unilateral Cerebral Palsy

The second version of the Children's Hand-use Experience Questionnaire (CHEQ 2.0) is an online questionnaire that is used to capture the child's experience of using the more impaired upper limb during 29 daily life activities for which usually two hands are needed. For each bimanual activity the parents are asked to indicate if the child or adolescent uses one or both hands to perform the activity or if assistance is needed. Followed by three sub-questions that are scored on a four-point Likert scale, indicating the (1) efficacy of the more impaired hand, (2) time needed to perform the activity compared to peers and (3) if the child feels bothered by the more impaired hand when performing the activity. For each sub-scale a total score will be calculated ranging from 0 to 100, with a higher score representing better performance.

3D motion analysis will be used to evaluate spatiotemporal aspects of bimanual coordination during the functional box-opening task. Parameter of interest are total movement time and goal synchronization, with higher score indicating worse bimanual coordination.

Bimanual coordination will further be objectified using the ball-on-bar task on the Kinarm Exoskeleton robot. Parameters of interest are determined based on previous research in children and adolescents with unilateral cerebral palsy and include bar tilt standard deviation, hand path length bias, reaction time difference and hand speed difference. For all parameters, a higher score indicated worse bimanual coordination.

For the perceptual boundary task, the slope of a psychometric curve will be calculated. The slope describes how sensitive someone can discriminate angular displacements during reaching movements, with lower values indicating better performance.

The Kinarm Exoskeleton robot will be used to measure proprioception of the proximal upper limb joints (i.e., shoulder and elbow) during three uni- and bimanual proprioceptive assessments: (1) the contralateral position matching task, (2) the perceptual boundary task and (3) the indicating location task. The contralateral position matching task results in four parameters; absolute error, variability, systematic shift and contraction/expansion. For the first three parameters a higher value represents worse task performance. For the last parameters (contraction/expansion), a value of 0 indicates perfect alignment while a lower or higher score indicates contraction or expansion, respectively.

For the indicating location task, where participants will be asked to indicate the perceived location of the tip of their index finger, the outcome parameter is the number of correct responses. This score ranges from 0 to 24, with a higher score indicating better performance.

Distal proprioception of the metacarpophalangeal joint of the index finger will be investigated using a position sense task on the ETH MIKE robot. This results in two parameters of interest: the mean absolute error between the actual and the indicated position across the 11 trials and the mean variability over these trials. For both parameters a higher score indicates worse performance.

Tactile registration will be determined by identifying a threshold value using the Semmes Weinstein monofilaments. Tactile registration will be classified as normal (0.008-0.07 gram), diminished light touch (0.16-0.4 gram), diminished protective sensation (0.6-2 gram) and loss of protective sensation (4.19-300 gram).

Static two-point discrimination will be measured with the aesthesiometer by identifying the smallest distance that can correctly be sensed as two separate points. This score will range from 2 till 10 millimeters, with a higher score indicating worse performance.

Tactile perception will further be objectified using the Tactile Discrimination Test, which is a three-alternative forced choice response test where participants are guided to feel several triplets of textures and are asked to identify the texture that is different from the others. The final score will be transformed to an converted to an Area Under the Curve threshold score with a higher score indicating better performance.

Three different components of tactile perception will be assessed: (1) stereognosis or tactile object recognition, (2) two-point discrimination and (3) texture discrimination.Tactile object recognition will be assessed by identifying six familiar objects based on touch. The final score will be the total amount of objects that were correctly identified, ranging from 0 to 6 with a higher score indicating better performance.

Unimanual motor skills will be assessed using the instrumented Tyneside Pegboard Test, during which the time needed to transfer 9 medium-sized pegs from one board to an adjacent one is measured. A higher score, meaning a longer task duration, indicates worse unimanual motor skills.

The Canadian Occupational Performance Measure (COPM) will be used to assess the children's self-perceived occupation performance over different categories, including self-care, leisure and productivity. The parents or caregiver rates performance and satisfaction for each functional goal on a ten point ordinal scale, where 1 = "not able to do it all"/"not satisfied at all" and 10 = "able to do it extremely well"/"extremely satisfied".

Goal attainment will be objectified using the Goal Attainment Scale (GAS) for at least two individualized therapy goals. The GAS enables the conversion of goal attainment on a 5-point scale into t-scores. The score for each functional outcome ranges from -3 to 2. The participant's baseline performance is represented by a score of -2. Improvements in functional goal performance correspond to scores ranging from -1 to +2, with score 0 being the expected outcome. Deterioration in functional goal performance results in a score of -3.