Non-invasive detection of cerebral vasospasm

Cerebral vasospasm is detected in subarachnoid hemorrhage patients by use of highly sensitive accelerometers in contact with the head. Acceleration data can be investigated in the time domain, typically averaged over a number of heartbeats, to detect a drop in energy during diastole, and diastole/systole ratio can be compared with known data of normal and vasospastic patients. Data from one or more accelerometers can also be subjected to FFT and optionally plotted in a waterfall diagram, to observe the appearance of energy at higher frequencies as 50 Hz to 1000 Hz, also indicating vasospasm.