Phase Coordination between Intracranial Pressure and Electrocardiogram Signals.

Methodologies of deriving phase information from pulsatile intracranial pressure (ICP) signal and characterizing its phase coordination with electrocardiogram (ECG) signal were discussed. The application of ICP phase characterization methods to data from several clinical contexts showed that 1) Unstable periods of ICP were associated with a decreased ICP phase coordination with ECG; 2) Surgical treatment of Chiari malformation patients caused an increase of phase coordination; 3) Changes of cerebral vascular tone could also lead to changes of ICP and cerebral blood flow velocity phases relative to arterial blood pressure. The results of our analysis could shed some light on a new tuned-oscillator theory of intracranial pulsatile dynamics as well as support phase characterization of signals as a new way of extracting clinically useful information from ICP and cerebral hemodynamic measurements.