- lack of decisional capacity [*'Decisional capacity' is defined as the ability to participate in effective decision making and provide informed consent. That is, in the judgment of the examiner, the patient, after reading the IRB approved patient consent document (or having it read to them) can (a) generally understand the terms of participation in the study: the purpose of the study, what will be required of study participants; the potential risks, benefits and alternatives of study participation; pros & cons of study involvement and (b) can communicate a choice in his/her own words (or write on a communication board)]