Non-invasive assessment of ICP waveform dynamics as an Adjunctive Diagnostic and Monitoring Tool for Normal Pressure Hydrocephalus in Patients Subjected to Ventriculoperitoneal Shunt Procedures

Introduction: Normal Pressure Hydrocephalus (NPH) arises from changes in intracranial compliance. The widely practiced treatment is Ventriculoperitoneal shunt (VPS) surgery, draining excess cerebrospinal fluid. This research evaluates the P2/P1 intracranial pressure waveform ratio, captured non-invasively, as an accessory assessment and diagnostic method for NPH.

Methods: The study encompassed seven NPH patients, assessing the P2/P1 ratio, TTP, confidence intervals for P2/P1 ratios and valid waveforms pre and post VPS surgery. Intracranial compliance evaluation was conducted in various postures: lying, sitting, 30 degrees inclination, and upright. Pre- and post-surgery ICP waveform dynamics, such as P2/P1 ratio and time-to-peak, were scrutinized.

Results: Our study's results indicate that all patients experienced improvement in at least one parameter after VPS, with 67% showing enhanced P2/P1 ratios and 44% showing improvements across all evaluated parameters. Although a direct correlation between the number of symptoms improved and the number of parameters improved was not established, the majority of patients with more symptoms improved also showed improvements in more parameters. A significant limitation of our work is that patients were also monitored once before and after shunts and not all patients were monitored in the same positions, which may cause variations.

Conclusion : nICPw dynamics may serve as an additonal non-invasive diagnostic and monitoring criterion for NPH. Despite evident pre and post shunt disparities, refining monitoring routines remains essential to discern optimal cut-off values. Expansive research and clinical trials are imperative to further delve into the potential of non-invasive waveform analysis in the management of NPH patients.