Weight, height and body composition are important indicators for development. The tools used to measure these can be different for children with cerebral palsy.
Cerebral palsy is a damage to the developing brain in the motor part of the brain. Individuals with cerebral palsy have problems with weakness and sometimes also involuntary movements.
Every educator needs to make a decision about technology they need to put in place. They're not sure if they should put Option A in place or Option B in place. This can be particularly difficult in the world of disabilities because there might not always be a perfect answer. Teachers can look to this solution, using the least dangerous assumption to make good decisions about what technology might be best.
When you don't have enough evidence about a student's performance, assume they can do whatever you're asking them to do.