Patients with chronic daily headache with suspicion of intracranial hypertension selected. Selection based on clinical symptoms (headache description, leading symptoms)and para-clinical pathological findings (optical nerve papilla edema). Not enough evidence to diagnose any other headache type. Simultaneous CSF pressure measurements and non-invasive ICP measurement will be performed.

Interventions: non-invasive intracranial pressure measurement; lumbar puncture and cerebrospinal fluid pressure measurement; brain MRI/CT.

Multiple sclerosis (MS) group patients selected based on clinical symptoms and brain MRI changes typical for the disease. Diagnosis based on McDonalds criteria. CSF test for oligoclonal bands required as supporting diagnostic criteria. Patients selected with disease relapse symptoms. Simultaneous noninvasive ICP and CSF pressure measured.

Interventions: non-invasive intracranial pressure measurement; lumbar puncture and cerebrospinal fluid pressure measurement; brain MRI/CT

Patients selected for this group have stroke/intracranial hemorrhage that might be complicated with intracranial hypertension. Stroke/intracranial hemorrhage diagnosed based on clinical findings and changes on brain CT/MRI. Patients with stroke less than 33% of middle cerebral artery territory included. Patients with intracranial hemorrhage 20-40 ml volume included. Patients unable to cooperate or sign informed consent excluded.

Bilateral non-invasive ICP measurements performed. Results compared with brain MRI/CT lesion volume, mid-line shift.

Interventions: non-invasive intracranial pressure measurement; brain MRI/CT

The noninvasive ICP measurement device Vittamed 205 aICP meter used in this study has been developed in Lithuania. The method is based on two-depth transcranial Doppler technique for simultaneously measuring flow velocity pulsatilities in the intracranial and extracranial segments of the ophthalmic artery (OA). These measurements are made while applying a series of small pressure steps to the tissues surrounding the eye-ball. The intracranial segment of the OA is compressed by ICP and the extracranial segment of the OA is compressed by the externally applied pressure Pe. Blood flow pulsatility parameters in both of these OA segments are monitored.Pulsatilities are approximately the same when Pe = ICP. Two-depth TCD device is used as an indicator of the pressure balance point.

Brain MRI/CT data will be used to compare ocular nerve sheath diameter (in mm) and stroke/ intracerebral hemorrhage volume (in cubic cm) with CSF pressure and non-invasive ICP.