An electrical stimulation lead assembly includes a lead body having a distal end portion, a proximal end portion, and a longitudinal length. Electrodes are disposed along the distal end portion of the lead body; terminals disposed along the proximal end portion of the lead body; and stimulation conductors couple the terminals to the electrodes. A cerebrospinal-fluid-pulsation detection assembly includes a sensor disposed along the distal end portion of the lead body. The sensor detects pulses of cerebrospinal fluid within a subarachnoid space of a patient and transforms the detected cerebrospinal-fluid pulses into sensor signals. A sensor processor receives the sensor signals from the sensor, processes the received sensor signals to cerebrospinal-fluid pulsation data (“CSF-pulsation data”), and estimates a patient blood-flow condition based on the CSF-pulsation data. A sensor control pathway couples the sensor to the sensor processor.