Noninvasive Measurement Of Intracranial Pressure With Flash Visual Evoked Potentials

The relationship between intracranial pressure (ICP) and latency of visual evoked potentials (VEP) was investigated in 1984 by York DH, He found a linear relationship between elevated intracranial pressure in patients with hydrocephalus and with cerebral edema and a latency shift of the N2 wave of the flash-evoked cortical potential is demonstrated. But we do not know whether this relationship is applicable to other diseases. We want to research the relationship between flash visual evoked potentials (FVEP)and ICP. to evaluate the usefulness of baseline FVEP testing in the diagnosis of increased ICP in other diseases. And to Analysis The character of N2 waves and select the best measurement of lantcy as a parameter in monitoring ICP. So we made these test. Method22 normal individuals, 44 increased intracranial pressure patients and others 35 patients, which were measured by Lumbar puncture, were recorded with FVEP. We compared the latency of their waves .And other 40 patients were recorded by FVEP for three times in 10minutes. We summarized the character, the variation and the lantcies of N2 waves. We compared the difference of 4 measurement in lantcy of N2 wave in the same pation for the same time o ResultsA positive correlation ship between elevated intracranial pressure and alatency shift of the P2 , N2 , P3, N3 wave of the flash-evoked potential is demonstrated. The latency shift of PI, Nl wave only be observed in a higher ICP. we find the N2 wave is unconstant and it's amplitude is un -relative to ICP .additional we also find it is wider than Nl wave and has a deep P2 in the front of it and a deep P3 in the post of it .our research implied that the peak lantcy of N2 is unstable .and the Intermedium lantcy have the minimum variation in all of 4 measurements ?ConclusionA linear relationship between elevated intracranial pressure and the latency of P2, N2, P3. N 3 wave and FVEP is a reliable noninvasive method to Monitoring intracranial pressure. The N2 wave is mutable even though for the same people in the same time. We suggest we should choose the Intermedium lantcy as parameters for monitoring ICP.