Each enrolled patient will be monitored with the HS-1000 device for a period of 10 minutes, occurring daily, after completion of surgery for SAH. Following admittance to the intensive care unit (ICU), patients will undergo routine monitoring as per standard of care. Non-invasive recordings of 10 minutes in duration with HS-1000 device will be completed daily for up to 14 days contingent on staff availability and the patient's clinical status. In the event a monitoring session is interrupted or postponed, another attempt to re-monitor will be made when the patient is able. Flexibility will granted in lieu of patient or study team unavailability thereby allowing recording to be neglected for any given day if absolutely necessary.