Fig. 6.

The impact of premature extrauterine development on stimulus-evoked response template magnitudes. Response magnitudes were assessed using the template analysis approach, and group average response magnitudes were compared between the very preterm infants (<32 weeks) and late preterm infants (34–36 weeks). Both groups were assessed at matched PMA of 34–37 weeks. Visual-evoked template magnitudes were calculated at electrode Oz, and tactile- and noxious-evoked template magnitudes were calculated at electrode Cz. (A) Quantitative comparison of evoked template magnitudes between groups using linear random effects regression model. Compared to the late preterm infants, the very preterm infants had significantly larger visual-evoked response magnitudes (left) and significantly smaller tactile-evoked response magnitudes (middle). There was no significant difference between the groups for the noxious-evoked response magnitudes (right). For all plots, d = Cohen’s d displaying the standardised difference in mean magnitudes; p = two-sided p-values. (B) Heat maps display the spatial patterns of the stimulus-evoked deflections, for qualitative assessment between groups. The timeseries display the templates (in red) superimposed onto the average EEG response (black) 500 ms pre-stimulus and 1000 ms post-stimulus for qualitative assessment of variable response magnitudes between groups. Colour bar indicates the template magnitude scaling. For all stimulus modalities, the templates fit the data well in both groups, and response topography patterns did not appear to be noticeably different between groups. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)