Seventy eight volunteers were screened where 13 were found not eligible based on the inclusion and exclusion criteria, 8 cancelled their appointment before enrolling, and 57 were consented and completed all procedures of the study. Forty one of the 57 volunteers were accrued since last year (2010). Enrolment is dependent on the type of patients enrolled in other NINR protocols requiring age-, gender-, race-matched controls. Recruitment conducted by self-referral or by referrals from the Clinical Research Volunteer Program of the Patient Recruitment and Public Liaison Office.