Spectral analysis of intracranial pressure signals recorded during infusion studies in patients with hydrocephalus

Effect of infusion tests on the dynamical properties of intracranial pressure in hydrocephalus

“…Infusion was performed through a caudal needle with an infusion pump (Lifecare ® 5000, Abbott Laboratories) connected to the needle through a three-way stopcock. [8,18].…”

“…At this point, the plateau pressure (P p ) was measured. CSF pressure was still recorded after infusion stopped, until it decreased towards baseline levels [8,18]. A qualified neurosurgeon visually selected four artefact-free epochs in each recording [8,18]:…”

“…Furthermore, ICP signals were filtered using a finite impulse response (FIR) band-pass filter with cutoff frequencies 0.02 and 5 Hz. These frequency limits ensured that the meaningful spectral content of the recordings was preserved, while the DC component was minimised [18].…”

“…Moreover, reduced complexity seems to be linked to poor outcome after TBI [14]. On the other hand, previous studies addressed the spectral analysis of ICP signals [11,[16][17][18]. Thereby, the reconstruction of an ICP signal from its first harmonic was accomplished [17].…”

“…Finally, the study of very low frequency components of the ICP signal (slow waves) has also received interest [16]. In our previous research, we addressed the spectral analysis of ICP recordings from ITs using median frequency and relative power [18]. The morphology of ICP pulse waveforms has also been analysed to characterise ICP dynamics [19][20][21].…”