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Grand averages of transient visually evoked cortical potentials in pressure tolerance testing of the optic nerve head


, : Grand averages of transient visually evoked cortical potentials in pressure tolerance testing of the optic nerve head. Fortschritte der Ophthalmologie 87(1): 32-36

Transient visually evoked cortical potentials were recorded during an artificial stepwise rise of intraocular pressure. At each pressure step one average was taken. The reversal rate was 1.9 Hz. Two groups of 30 healthy volunteers each were examined: in group one 25 sweeps were averaged and in group two 50 sweeps. Thus the recording time in group two was doubled compared to group one. When all subjects were examined the evoked potentials of the 30 subjects were averaged at each pressure step: the results was a "Grand Average" at the different pressure steps applied. The amplitudes of N2-P2 were plotted versus the intraocular pressure. It is seen that a not monotone or weakly monotone function in the amplitude/pressure curve is more clearly seen in the averages of 25 sweeps. We interpret this result as follows: a not monotone or weakly monotone behaviour is a sign of autoregulation in the optic nerve head. This sign is more clearly shown at a short recording time. The majority of healthy persons show autoregulation, the majority of glaucoma patients do not. According to the results presented here it is advisable to apply short recording times in clinical pressure tolerance testing of the optic nerve head. A short recording time enhances the accuracy of the test.

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Other references

Westphal, D., 1977: Neue Brutnachweise und Vorkommen des Zwergschnappers (Ficedula parva) in West Berlin. Ornithologischer Ber Berl (West): 21: 3-20

Feldpausch, T.R.; McDonald, A.J.; Passos, C.A.M.; Lehmann, J.; Riha, S.J., 2006: Biomass, harvestable area, and forest structure estimated from commercial timber inventories and remotely sensed imagery in southern Amazonia. The purpose of this study was to determine if spatially-explicit commercial timber inventories (CTI) could be used in conjunction with satellite imagery to improve timber assessments and forest biomass estimates in Amazonia. As part of a CTI, all...

Hall Chris M.; Farrell John W., 1993: Laser (super 40) Ar/ (super 39) Ar age from ash D of ODP Site 758; dating the Brunhes-Matuyama reversal and oxygen isotope stage 19.1. Eos, Transactions, American Geophysical Union 74(16, Suppl

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Kardin M.K.; Percich J.A., 1983: Resistance of bipolaris oryzae to fenapanil. Fenapanil-resistant strains of B. oryzae [isolated from wild rice, Zizania aquatica] were obtained by successive transfers on a series of fenapanil-amended potato-dextrose agar media containing increasing concentrations of the fungicide or by sele...

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