DELPHI in Subjects at Risk for Stroke and Dementia

Transcranial magnetic stimulation (TMS) is a noninvasive brain stimulation method that allows to study human cortical function in vivo. Using TMS for examining human cortical functionality is enhanced by combining TMS with simultaneous registration of electroencephalograph (EEG). EEG provides an opportunity to directly measure the cerebral response to TMS. Measuring the cortical TMS Evoked potential (TEP), is used to assess cerebral reactivity across wide areas of neocortex. By evaluating the propagation of evoked activity in different behavioral states and in different tasks, TMS-EEG has been used to causally probe the dynamic effective connectivity of human brain networks. In this study the sponsor is intended to collect data of subjects at the ages of 50-75, at risk for stroke and dementia using DELPHI, brain MRI scans, cognitive tests and clinical and demographic information. Some of the patients agreeing to perform a second test will serve for a reliability test. Primary Objectives: 1. Definition of DELPHI's average TEP response of at risk for stroke and dementia population in subjects over 50-75 years old+/- STD. 2. Assessing the Safey of the use of DELPHI in at risk for stroke and dementia population. 3. Defining DELPHI's test-retest reliability by quantifying correlation coefficient between two tests. Exploratory objectives: 1. Evaluating the sham stimulation effect. 2. Assessing confounders effecting results. Subjects will perform a medical interview, neurological exam, cognitive evaluations, two emotional inventories and a brain MRI scan.