Prevalence of Fear in Young Children Towards the MRI Environment

. These data are inadequate for estimating the prevalence of fear in pediatric volunteers or their willingness to participate in MRI research studies. One reason is that the large majority of existing data were gathered in clinical settings from participants who were receiving the MRI to diagnose a potentially serious medical condition. These situations present additional stresses to patients and may exacerbate fearful reactions to the MRI environment. The difference, if any, between prevalence of fear under these conditions versus that in the MRI research contexts is unknown. To our knowledge there are no published data available to researchers and ethics boards regarding the prevalence of fearful reactions that pertain specifically to children, and especially to younger children in research studies. We found that approximately 50% of children between the ages of two and seven would be willing to enter a MR imaging environment. Gender does not appear to be a significant factor as 52% of males and 50% of females completed the hierarchy. Successful completion of the hierarchy improved with age, with 75% of children aged 6 and 7 years completing all of the steps compared to only 35% between the ages of 2 and 4 and 50% between 4 and 5 years of age. The greatest stumbling block for cooperation in MRI research studies is the act of lying down on the patient table (steps 5 and 6). Of the children who did not complete the hierarchy, this position of vulnerability caused the most unease (68%). Only three subjects (18%) who did not complete the hierarchy indicated fear of the MRI system noises. We expect these numbers to be higher in developmentally delayed populations (such as autism spectrum disorders or fetal alcohol spectrum disorders) compared to the typical healthy controls enrolled in the current study. In our experience, children are often excluded from MRI research and its potential benefits because of concerns about physical or psychological risks. In this study we gathered data that may help to prevent exclusion or inclusion based on inaccurate estimates of the risk of fear during MRI studies. Researchers who work with pediatric volunteers between the ages of 2 and 5 years should factor into their calculations for group size a failure rate of approximately 57% for children entering the imaging environment (this does not include experimental failure due to motion and other factors) and 25% for children aged 6 and 7 years. These numbers can likely be reduced if researchers commit the extra time, care and effort required to acclimatize the children to the MR environment by successive approximations to the requirements for the actual imaging study.