2. Informed consent. Verbal consent to be screened will be obtained over the telephone prior to collecting information on demographics and medical and psychiatric history. Written consent will be obtained with the affected individuals and caregivers together, as described in more detail below. The consent forms will be reviewed and capacity to consent will be assessed in primary participants based on responses to questions to determine level of understanding of study procedures, risks, benefits and rights. Participants who do not demonstrate capacity to consent will be asked to assent to study procedures and caregivers will be asked to consent on their behalf. A separate consent form will request permission to participate in video recording of exercise classes for quality control purposes. After the consent process has been completed, the Modified Mini-Mental State Exam (3MS) will be administered to affected individuals to assess level of cognitive impairment. Consent procedures will take place at the Kaiser group room unless otherwise requested by caregivers.