This study will involve recordings using MindRhythm's Harmony 4000, a novel, non-invasive investigative medical device. The Harmony 4000 collects accelerometry data on the motion of the skull resulting from the movement of the brain during each cardiac cycle. The motion of the skull due to brain movement is named the HeadPulse by MindRhythm. The HeadPulse, cranial accelerometry, has been shown to provide clinically relevant data for concussion, vasospasm and Large Vessel Occlusion (LVO) stroke (Wade Smith, 2015). The Harmony 4000 is a headband and is self-contained. Control of the device is provided by pushbuttons (on and off) on the headband and via an MindRhythm iPhone app. The objective of this non-significant risk (NSR) study is to collect HeadPulse waveform recordings from 500 normal subjects to be used as controls when developing algorithms for trials in stroke, concussion and other neurological conditions. The data set of normal subjects will allow evaluation of repeatability and variability of HeadPulse recordings within a subject and between subjects. Collecting un-blinded HeadPulse waveform with the Harmony 4000 from normal adult subjects including and above the ages of 18 during normal circumstances will create a comparative cohort. These normal data sets will assist in improving the diagnostic capabilities of the Harmony 4000 device in detecting neurological abnormalities including but not limitied to stroke, stroke type, and concussion. These subjects will be recorded once or multiple times as a time series covering recordings up to two years in duration. A secondary endpoint will be to determine the quality of recordings obtained when subjects are permitted to make their own recordings without supervision after iPhone app based training.

Participant's will be recruited to volunteer to provide intracranial waveform data with the understanding that they are considered "healthy" subjects. Upon downloading the iPhone MindRhythm study app, subjects will be asked a series of questions related to inclusion and exclusion criteria, and presented with a consent form that describes the study, and what will be asked of them. Upon subject's direct consent (no LARS) to participate in the study, participant will be enrolled and sent a Harmony headset kit that will include brief training instructions for both the use of the headset and the iPhone app, ECG leads and the Harmony headset. Participant will follow the instructions and provide recordings by way of the app at the same time of day and based on a specified physical position that will suggested and recorded in the app. The subject will be instructed as to how to connect the ECG leads and place the pads on the chest and abdomen. As the "Headpulse" which is the intracranial waveform detected by the Harmony headset and is as a result of the natural movement of the brain immedliately following the cardiac cycle, the ECG data must also be recorded in conjunction with the cranial readings. The subject will connect the headset to their app by way of bluetooth once a position has been chosen and leads are connected. Upon connection, the subject will maintain a still and quiet position for a period of 3 minutes while the app collects the waveform data. Upon completion of the 3 minutes, an audible chime will occur and data will stop being transmitted and recorded. The subject will then transmit that data under their patient ID number to study investigators by way of a HIPAA compliant cloud based transmission and storage system. The subject has the option to withdraw from the study at any time by way of the iPhone app and/or the PI has the option to withdraw the subject from the study.