healthy subjects and four patients with intracranial hypertension, but larger validation studies have never been conducted as the method failed to attract enough interest among clinicians. This method also needs a calibration to the individual patients. Cerebral ventricle Michaeli proposed that ICP should be inferred from the magnitude and shape of pulsations of the third ventricle synchronous with the cardiac cycle or respiration, where the pulsations are measured along the propagation axis of an ultrasound wave. The method so far has not been independently validated, and the author provides no exact data from which one could estimate the accuracy of the method. However, the discussion in the body of the patent document suggests that the method is able to distinguish among three ranges of ICP (<20, 20–40 and >40mmHg) but cannot provide an exact value of ICP within the range because of the impossibility of the calibration to the individual patient. Method and device for non-invasive (NI) ICP measurement according to inventions of David Michaeli MD, PhD, based to the TRA (tissue resonance analysis) have 2 options: (1) The qualitative method makes an evaluation of mild (10-20mm.Hg), moderate (20-40) and severe (above 40mmHg) ICP elevation. These method is using NI, long-term recording of ICP waves patterns, Like Lundsbergs ICP waves. (2) Quantitative measurement OF ICP WAVES with special ICP formulation in mm.Hg., Developed new device and method for calibration of ICP for each patient; see patent description. Brain parenchyma More recently, multivariate methods have been proposed that derive ICP by combining the transit times with measured acoustic impedance, resonant frequency and ultrasound velocity, or with a dispersion of the ultrasound wave on its way through the brain parenchyma. Ultrasound ICP monitors based on the latter approach, which were developed at Vittamed Technologijos (Kaunas, Lithuania), have shown an impressive agreement with invasively measured ICP, with an average difference of only 2–3 mmHg in a small clinical population. However Vittamed Technologijos time-of-flight technologies were developed further for other applications of neuro-monitoring technologies (including cerebral Autoregulation and Cerebral Compliance). Transcranial Doppler ultrasonography The TCD measures the velocity of blood flow through the major intracranial vessels by emitting a high frequency (>2MHz) wave from an ultrasound probe and detecting a frequency shift between the incident and reflected wave which directly correlates with the speed of the blood (the so-called Doppler effect). The measurement is taken over the regions of the skull with thinner walls