Click link to read a guide to the language used in Personal Independence Payment (PIP) assessment criteria:
https://www.citizensadvice.org.uk/Global/Guide%20to%20the%20language%20used%20in%20the%20PIP%20assessment%20criteria%202019.pdf

More information on CAB website:
https://www.citizensadvice.org.uk/benefits/sick-or-disabled-people-and-carers/pip/appeals/how-decisions-are-made/