the performance study is essential with respect to incapacitated subjects and data of comparable validity cannot be obtained in performance studies on persons able to give informed consent, or by other research methods;
tá an staidéar feidhmíochta sár-riachtanach maidir le hábhair éagumasaithe agus ní féidir sonraí atá inchomparáide ó thaobh bailíochta de a fháil ó staidéir feidhmíochta ar dhaoine atá in ann toiliú feasach a thabhairt nó ó mhodhanna eile taighde;