Headache responses to M-CPP in OCD and normal controls

Abstract

activities in short segments of data, and during acute challenge studies to induce panic attacks. This method ensures that one does not lose important information during quick changes in cardiac sympathetic and parasympathetic activities. This method can also be used on long data segments, and the results are comparable to traditional spectral analysis or nonlinear techniques such as fractal dimensions. Using this technique, we found very high increases in sympathovagal ratios in patients during lactate and isoproterenol infusions, especially when they had panic attacks. Similar changes were also noted during human sexual activity at the time of orgasm, analyzed from the 24-hour Holter records of ECG. Complex demodulation also allows one to quantify time-dependent changes in the LF (0.04--0.15 Hz) power. This may be an important technique to analyze heart rate time series during heightened sympathetic activity, as there is a consistent peak in the time series of the LF amplitudes around 0.2 Hz, which is related to muscle sympathetic activity. Complex demodulation can be performed on heart rate time series using center frequencies of 0.09 and 0.31 Hz for the LF and HF powers with pass frequencies of 0.05 and 0.15 Hz. We use a 61 -term low-pass filter using a published algorithm for a zero-phase-shift least-square filter with convergence factors.