Invasive intracranial pressure (ICP) monitoring is highly effective, but involves risks. HS-1000 measures ICP non-invasively by assessing the acoustic properties of the patient's head. HS-1000 device, a proprietary new non-invasive ICP monitor, is expected to safely and accurately monitor ICP with minimal discomfort to patients, and provide information about normal or elevated ICP levels to the physicians.

The study objective is to compare the accuracy and safety profile of HS-1000, a non-invasive ICP monitor, to invasive ICP monitoring via an external ventricular drain (EVD)

HS-1000 device, a proprietary new non-invasive ICP monitor, is expected to safely and accurately monitor ICP with minimal discomfort to patients, and provide information about normal or elevated ICP levels to the physicians

Inclusion Criteria:

• Adult men and women subjects, aged 18 years old and over at screening visit
• Patients undergoing invasive ICP monitoring via an external ventricular drainage (EVD) device for clinical management
• Survival expectancy greater than one week
• Subject or legal authorized representative (per local regulation) is able and willing to comply with the requirements of the protocol
• Subject or legal authorized representative (per local regulation) is able to understand and sign written informed consent to participate in the study

Exclusion Criteria:

• Subject with ear disease, ear trauma
• Subjects with a bony abnormality (skull defect)
• Subjects with severe head trauma in which the location and/or severity of the skull fracture(s), i.e. frank skull fracture or major joint dislocations may jeopardize HeadSense monitoring procedure
• Subjects with cerebral fluid (CSF) leakage from the ear (CSF Otorrhea)
• Known allergy or hypersensitivity to any of the test materials or contraindication to test materials
• For women of childbearing potential: pregnancy (positive pregnancy test) or breast-feeding
• Subjects currently enrolled in or less than 30 days post-participation in other investigational device or drug study(s), or receiving other investigational agent(s)
• Any condition that may jeopardize study participation (e.g., abnormal clinical or laboratory finding) or interpretation of study results, or may impede the ability to obtain informed consent (e.g., mental condition)