[The various components of averaged visual evoked potentials in man]

Developmental wave form analysis of the neonatal flash evoked potential

A multiple regression technique was used to describe the wave form of the flash evoked potential (VEP) in 64 neonates born between 28 and 39 weeks of gestation. The successive appearance of new features in the VEP with increasing gestational age at birth was used to define 5 components, of which specimens were obtained by averaging VEPs of 18 selected infants. The VEPs of the other 46 infants were expressed as linear sums of the components, each multiplied by a weighting coefficient. The method accounted for 74 +/- 11% (mean +/- 1 S.D.) of the rms power of the observed VEPs and was used to demonstrate significant effects on wave form maturation from fetal growth retardation and maternal smoking in pregnancy.

Regional relationship of visual evoked potentials in infants and school-aged children

VEPs were recorded from the inion, O1, O2, Pz, C3 and C4 in 74 normal children, aged 1--13 years. These VEPs were compared at the various scalp areas using a correlational technique. Wave forms of VEPs were different for different scalp areas; in particular, a sharp distinction was seen in the positive component having a peak latency of about 100 msec. The component was occipital-dominant, showing a maximum amplitude at the inion. Correlations of VEPs from the right and left hemispheres of the central area were high for all ages, while those of the right and left hemispheres of the occipital area were generally lower and showed greater inter-individual variability than in the central area. Correlations between VEPs from the occipital and non-occipital areas (i.e., inion-Pz, inion-C4, O1-C3 and O2-C4), with the exception of inion-Pz, were significantly greater with increasing age.

[Original method of multivariate analysis, adapted for comparison of mean evoked potentials: E2 test]

This paper describes a multivariate statistical method of analysis for the comparison of 2 paired series. For such paired series, this test, called E2, is analogous to the generalized Hotteling T2 test, as epsilon test (pairing method) is analogous to Student's t test. Here we give an example of its application to a comparison of curves, in this particular case average auditory evoked potentials, picked up at symmetrical points on the scalp.