Measuring oscillatory potential during the course of an arterial occlusion: a method based on Fourier analysis.

Recently we developed a quantitative method of measuring the Oscillatory Potentials (OP's) for a clinical study in diabetic patients. Several problems were experienced in interpreting the results obtained with digital filtering. The main dilemma was the separation of the first OP from the a-wave, since their frequencies are within the same range. The fast Fourier transform (FFT) was applied for this purpose. From the FFT response the power of the OP's was calculated and expressed in microwatts. The advantage of this method is clearly demonstrated in the case of a patient with central retinal arterial occlusion.