Normal pressure hydrocephalus (NPH) encompasses a heterogeneous group of disorders generally
characterised by clinical symptoms, ventriculomegaly and anomalous cerebrospinal fluid (CSF)
dynamics. Lumbar infusion tests (ITs) are frequently performed in the preoperatory evaluation of
patients who show NPH features. The analysis of intracranial pressure (ICP) signals recorded during
ITs could be useful to better understand the pathophysiology underlying NPH and to assist treatment
decisions. In this study, 131 ICP signals recorded during ITs were analysed using two continuous wavelet transform (CWT)-derived parameters: Jensen Divergence (JD) and Spectral Flux (SF). These
parameters were studied in two frequency bands, associated with different components of the signal:
𝐵"(0.15 - 0.3 Hz), related to respiratory blood pressure oscillations; and 𝐵# (0.67 - 2.5 Hz), related to
ICP pulse waves. Statistically significant differences (𝑝 < 1.70 ∙ 10+,, Bonferroni-corrected Wilcoxon
signed rank tests) in pairwise comparisons between phases of ITs were found using the mean and
standard deviation of JD and SF. These differences were mainly found in 𝐵#, where a lower
irregularity and variability, together with less prominent time-frequency fluctuations, were found in
the hypertension phase of ITs. Our results suggest that wavelet analysis could be useful for
understanding CSF dynamics in NPH.
