P3B-3 Staining Doppler Audio

Carotid stenoses are responsible for many of the strokes occurring each year. We have developed a low-cost-of-use instrument for use in primary-care physicians\´ offices that can detect these stenoses before they produce a stroke. Non-specialists are to use the instrument with only limited training, so it is desirable to make the Doppler audio it produces as easy to interpret as possible. We present two techniques for doing so by processing or "staining" the original audio signal to make it easier for neophyte operators to recognize the information present in the signal. In a small user study, a technique based on adaptive filtering did not result in an improvement, but another technique based on adding a sine tone of varying frequency to the signal produced a significant improvement in accuracy over the unstained Doppler audio. The study also showed that untrained subjects were capable of performing quite well even on unstained audio