Bootle Blast is a series of 13 mini-games targeting different upper limb motor therapy goals. Bootle Blast is designed with many of the features of mainstream video games known to be appealing to young people. Game rewards are linked to meeting therapeutic objectives, such as daily play targets that are customizable to each child. Bootle Blast is played through movements of the upper limbs tracked via a low-cost camera/sensor (Microsoft Kinect, no hand-held controls needed). The movements required to play are customizable to each child's range of motion. Some of the mini-games are "mixed reality", where children interact and manipulate real-life objects (e.g. musical instruments, coloured building blocks) to play the game. The use of skeletal tracking and mixed reality enables both gross and fine motor skills to be practiced in line with each child's therapy goals and motor abilities.

During the baseline assessment, an occupational therapist will calibrate the video game to the child's therapy needs and functional abilities. Within a week of the first assessment, the research team will set up the video game in the participant's home where it will remain for 12 weeks. Training on how to play the game and a user manual will be provided. The researcher will work with each family to establish a play objective (minutes/day and days/week) that considers the family's schedule. Five-minute telephone check-in calls will be done weekly.

Addresses research question 1. Every time the computer is turned on to play the video game, a video game log is automatically generated. The game logs active play time (i.e. time in minutes spent actively engaging in therapeutic movements) and passive play time (e.g. time spent navigating menus). Additional data that is recorded in game logs includes: game scores, games played and time in each game, rewards collected, and location of the joints (e.g. elbow, shoulder) as tracked by the Microsoft Kinect sensor. Data recorded in the video game will be used to identify the percentage of children that met their weekly play time goal, and on how many weeks this goal was achieved.

Addresses research question 2. COPM evaluates self- or parent-reported satisfaction and performance on self-identified therapy goals. Participants will identify, with the help of the occupational therapists during the baseline assessment, 1-3 upper limb goals related to daily life activities (e.g., tie shoelaces). Parent and child will rate together performance and satisfaction with performance on a 10-point scale (1 is poor/low and 10 is good/high) for each goal.

Addresses research question 2. The AHA evaluates the use of the affected hand in assisting during the performance of 22 bimanual activities. Each task is rated on a 4-point rating scale (4=effective, 0= does not do). Tasks include object manipulation from the AHA toy kit, which are scored under the categories of general use, arm use, grasp and release, fine motor adjustments and coordination and pace. Rasch analysis converts raw scores into a logit-based scale ranging from 0-100, with higher scores representing a higher ability.

Active range of motion of the shoulder, elbow and wrist will be measured bilaterally via goniometer.