Keeping kids engaged: the effects of superimposed single-line cartoons on pattern reversal VEPs

Recording reliable pattern-reversal VEPs (prVEPs) in children is challenging due to limited attention. Superimposing dynamic cartoons may enhance engagement, but their effects on the prVEP are unclear.

Fifteen healthy adults underwent prVEP testing under three conditions: (F) fixation on a central target (standard condition); (C) free viewing of a single-line cartoon superimposed onto the checkerboard pattern; and (M) a mixed condition, in which participants maintained fixation on the central target while the overlaid cartoon played. Eye movements were tracked to verify stable gaze in conditions F and M and to record gaze positions and velocities during condition C. P100 amplitude and peak time were analyzed for check sizes of 60' and 15'.

Under condition (C) (free viewing), P100 was significantly reduced to 74% of that observed during F (standard fixation) at 60' (***p = 0.001) and to 82% at 15' (**p = 0.004), along with a reduction in peak time (60': - 2.4 ms, ***p < 0.001; 15': - 3.1 ms, **p = 0.009). The M condition (mixed condition, fixation with the cartoon) produced minor, mostly non-significant changes in amplitude (60': 88%, p = 0.076; 15': 96%, p = 0.383) and peak time (60': - 1.7 ms, *p = 0.045; 15': 1.1 ms, p = 0.056). Eye tracking confirmed that 90% (C) to 96% (F and M) of reversals occurred during stable gaze. In condition (C), gaze was on average directed approximately 2° below the central position used for fixation in the other conditions.

The effect of cartoon overlays on the P100 component of adult prVEPs is small, albeit statistically significant. The effects likely reflect subtle influences of attention and adaptation rather than eye movements. These findings support the use of a single-line cartoon in pediatric testing to enhance engagement and response reliability without compromising clinical interpretation.