The Functional Disability Inventory (FDI) [24] is a 15
item questionnaire assessing a child’s perceived activity
limitations across home, school, recreation, and social
domains. Separate versions are available for parents and
children, with both versions asking how much physical
trouble or difficulty the child would have had doing a
particular activity in the past few days on a 5-point scale
from “No Trouble” (0) to “Impossible” (4). A total functional
disability score is calculated by summing the raw
scores for the individual items (range = 0–60), with
higher scores reflecting greater disability. The reliability
and validity of this measure in assessing functional disability
has been well established [25].