A system configured to monitor autoregulation includes a medical sensor configured to be applied to a patient and to generate a regional oxygen saturation signal. The system includes a controller having a processor configured to receive the regional oxygen saturation signal and a blood pressure signal and to determine a cerebral oximetry index (COx) based on the blood pressure signal and the regional oxygen saturation signal. The processor is also configured to apply a data clustering algorithm to cluster COx data points over a range of blood pressures, identify a first cluster of COx data points that corresponds to an intact autoregulation zone for the patient, and provide a first output indicative of the intact autoregulation zone for the patient.