Abstract
Background Performing fMRI scans of children can be a difficult task, as participants tend to move while being scanned. Head motion represents a significant confound in functional magnetic resonance imaging (fMRI) connectivity analyses, and methods to limit the impact of movement on data quality are needed. One approach has been to use shorter MRI protocols, though this potentially reduces the reliability of the results.
Objective Here we describe steps we have taken to limit head motion in an ongoing fMRI study of children undergoing a 60 minute MRI scan protocol. Specifically, we have used a mock scan protocol that trains participants to lie still while being scanned. We provide a detailed protocol and describe other in-scanner measures we have implemented, including an incentive system and the use of a weighted blanket.
Materials and methods Participants who received a formal mock scan (n = 12) were compared to participants who had an informal mock scan (n = 7). A replication group of participants (n = 16), including five with autism spectrum disorder, who received a formal mock scan were also compared to the informal mock scan group. The primary measure of interest was the mean frame-to-frame displacement across eight functional runs during the fMRI protocol.
Results Participants in the formal mock scan and replication group tended to exhibit more low-motion functional scans than the informal mock scan group (P < 0.05). Across different functional scan conditions (i.e. while watching movie clips, performing an attention task, and during resting-state scans), effect sizes tended to be large (Hedge’s g > 0.8).
Conclusion Results indicate that with appropriate measures, it is possible to achieve low-motion fMRI data in younger participants undergoing a long scan protocol.
Footnotes
Declarations
Funding: This work was supported by a P50MH115716 grant. CH is supported by a Medical Scientist Training Program training grant (NIH/NIGMS T32GM007205).
Conflict of Interest: FRV receives book royalties from Wiley, Springer, Guilford Press, and Cambridge University Press. JCM consults with Blackthorn Therapeutics, has received research funding from Janssen Research and Development, and receives royalties from Guilford Press, Lambert, and Springer.
All other authors declare they have no conflict of interest.
Ethics approval: This study was approved by the Yale Institutional Review Board.
Consent to participate: Informed consent was obtained from the parents of participants. Written assent was obtained from children ages 13 – 17; verbal assent was obtained for participants under the age of 13.
Consent to publish: The authors affirm that human research participants provided informed consent/assent for publication of the results described here.
Availability of data/code: The data and code used in this study available upon request.