Operational decision not to proceed at this stage.

Intracranial pressure (ICP) monitoring is indicated in a wide range of neurological diseases. The combination of a linear ultrasound array with an integrated pressure sensor into a single handheld probe (ICP Probe) enables the user to precisely and non-invasively estimate blood pressure in a superficial vein overlying a hard structure. The periorbital vein located on the forehead above the eye is an interesting target since it is an emissary vein, directly connected through valveless vessels to the intracranial venous system. Its pressure might thus reflect intracranial pressure if it can be measured before being equalized by redistribution across the whole facial venous network. The usage of a pneumatic mask able to transiently occlude the site of measurement from the superficial venous network might therefore enable to correlate the venous occlusion pressure (VOP) of the periorbital vein to ICP. To confirm the hypothesis, the current clinical trial will compare measurements made with the CPMX3 system with invasively obtained ICP measures.

Inclusion Criteria:

1. Parent/guardian or alert subject (age 18 or over) capable of giving consent; subject less than 18 and of assent age must give assent to participate if appropriate and required by the institution. If the subjects are incapable of giving assent, then only parent/guardian consent is required
2. Male or female
3. Age: 8 to 21 years of age
4. Equipped with an ICP monitor (intraparenchymal probe or EVD) as part of standard of care

Exclusion Criteria:

1. Presence of facial trauma that could hinder placement of the pneumatic mask or contraindicate ultrasound on the forehead
2. Presence of fractures of the skull
3. Any other condition that would interfere with measurement technique and routine clinical care according to the judgment of the investigator.

Investigator performing the pressure measurement with CPMX3 will be blinded from the invasive intracranial pressure value for the duration of measurement with CPMX3