| Résumé | Seventy children aged 2 to 7 years were exposed to the MR imaging environment through a series of steps typical of a research study. Their willingness to proceed through the process was used to estimate the prevalence of fear. Thirty-seven children (53%, 95% CI [41%, 65%]) completed the approach sequence. Although the correlation of child age in months (M = 60.1, SD = 16.5, N = 70) and highest successful step (M = 5.8, SD = 2.6, 95% CI [5.2, 6.4]) completed was not statistically significant at the 0.05 level, r(68) = 0.21, p = 0.08, 95% CI [-0.03, 0.42], the proportion of children aged 6-7 yrs who successfully completed all steps (14 of 21, 67%, 95% CI [50%, 84%]) was significantly different from the proportion of children aged 2-3 yrs who completed all steps (6 of 23, 26%, 95% CI [11%, 41%]), (Fisher's Exact Test, two-tailed P = 0.0148). A failure rate of at least 50% should be included into group size calculations when performing studies with young children (2-7 years), in addition to motion and other experimental factors. |
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