- Evidence of active gastrointestinal, renal, pulmonary, endocrine or cardiovascular system disease sufficient to cause cognitive impairment or interfere with past levels of daily function; participants with controlled hypertension (supine diastolic BP < 95mmHg), right bundle branch block (complete or partial) and pacemakers may be included in the study; participants with thyroid disease also may be included in the study, provided they are euthyroid on treatment