Fast Fourier transform of individual cerebrospinal fluid pulse waves

In a previous communication, it was demonstrated that spectral analysis is valuable in evaluating cerebrospinal pressure waveforms. However, due to cardiac arrhythmias and alterations in the waveform related to the respiratory cycle, accurate spectral data could not be obtained. Accurate analysis was obtained by analyzing individual CSF pulse waves. This was accomplished by implementing a series of computer programs to condition the pulse wave before applying the Fast Fourier Transform. The analysis was performed in the following manner: sampling was obtained over multiple pulse waves. Peak analysis routines were utilized to isolate individual pulses. The pulses were filtered digitally. Interpolation techniques were employed to provide the necessary number of data points to implement FFT algorithms. Examples of the data and results of the technique are also given.