title: Spectral analysis of intracranial pressure signals recorded during infusion studies in patients with hydrocephalus.
abstract: Hydrocephalus includes a number of disorders characterised by clinical symptoms, enlarged ventricles (observable using neuroimaging techniques) and altered cerebrospinal fluid (CSF) dynamics. Infusion tests are one of the available procedures to study CSF circulation in patients with clinical and radiological features of hydrocephalus. In them, intracranial pressure (ICP) is deliberately raised and CSF circulation disorders evaluated through measurements of the resulting ICP. In this study, we analysed seventy-seven ICP signals recorded during infusion tests using four spectral-based parameters: median frequency (MF) and relative power (RP) in three frequency bands. These measures provide a novel perspective for the analysis of ICP signals in the frequency domain. Each signal was divided into four artefact-free epochs (corresponding to the basal, early infusion, plateau and recovery phases of the infusion study). The four spectral parameters were calculated for each epoch. We analysed differences between epochs of the infusion test and correlations between these epochs and patient data. Statistically significant differences (p < 1.7 × 10(-3), Bonferroni-corrected Wilcoxon signed-rank tests) were found between epochs of the infusion test using MF and RP. Furthermore, some spectral parameters (MF in the basal phase, RP for the first frequency band and in the early infusion phase, RP for the second frequency band and in all phases of the infusion study and RP in the third frequency band and in the basal phase) revealed significant correlations (p < 0.01) between epochs of the infusion test and signal amplitude in the basal and plateau phases. Our results suggest that spectral analysis of ICP signals could be useful for understanding CSF dynamics in hydrocephalus.
authors.affiliation: Biomedical Engineering Group, Department T.S.C.I.T., E.T.S. Ingenieros de Telecomunicación, University of Valladolid, Valladolid, Spain. maria.garcia@tel.uva.es
authors.forename: María
authors.initials: M
authors.lastname: García
authors.forename: Jesús
authors.initials: J
authors.lastname: Poza
authors.forename: David
authors.initials: D
authors.lastname: Santamarta
authors.forename: Daniel
authors.initials: D
authors.lastname: Abásolo
authors.forename: Patricia
authors.initials: P
authors.lastname: Barrio
authors.forename: Roberto
authors.initials: R
authors.lastname: Hornero
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000503:physiopathology; D016208:Databases, Factual; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000503:physiopathology*; D007260:Infusion Pumps; D007427:Intracranial Pressure; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted
keywords: Hydrocephalus; Infusion test; Intracranial pressure; Median frequency; Relative power