A better one is to insist you have not seen the document and have been forced to sign it to consent to a procedure that was time limited.
Now the onus is on the defense to show that it is not a common practice and who was responsible for that. Pretty excellent line to pursuit, hard to defend.
And easily dismissed when the defendant says "we showed him the document when he signed it. We show it to everyone" and now the onus is on prosecution to prove it.
The onus is not on the one who says it the loudest, it's on the one who can provide proof. The defense can explain to the judge that they turn the screen to show it or whatever it's supposed to do.
A contract signed under duress is not a valid contract.
There's no reason that the provider's testimony is magically preferred over the patient's, and in fact the generaly pratice is to resolve ambiguities in favor of the person who did not write the contract and is not the professional who has had plenty of pratice to know what they should be doing.
Now the onus is on the defense to show that it is not a common practice and who was responsible for that. Pretty excellent line to pursuit, hard to defend.