Table 4.

Adaptations made to the measurements

	Adaptations made(% of all participants that started measurement)
General adaptations (eye-tracking and fNIRS test environment)	- Participants were encouraged to sit in their own (wheel)chair (to increase comfort and decrease motion) - Some participants were strapped into their chair belts by the parent (to decrease motion) - Some younger participants sat in their parents’ lap - Several parents held their child’s hands when performing the measurements (to prevent the child from pulling off the equipment)
Eye-tracking:  - VOF  - Social preference	- In case of failed calibration at first attempt, the task was started using a pre-set calibration, and the data were calibrated after the measurement using a post-calibration method (71%) - No adaptations made
fNIRS	- Measurement started without fully optimizing light counts (removal of hair underneath the optodes), because the participant showed signs of protest (35%) - Reversal of filming direction for co-registration (start at CZ and end in front of the face, as starting filming in front of the face led the participants to watch along the direction of the camera)
Indirect calorimetry	- Parents/caregivers held their child or their child’s hands (54%) - Distraction: videos and pictures were shown on the Ipad (42%) - A toy to hold in their hands (13%) - The measurement was done first on the parent to show the child how it works (4%) - The child was measured sleeping in his own stroller (4%)
BIA	- Distraction was provided to the child in the form of a video or by making funny faces - Pillows were put underneath arms and between legs to prevent touching (13%) - The clips were hidden underneath a bandage (4%) - Parents held their child with non-conducting material in between them (4%)
BOD POD	- The BOD POD has a scale on which participants have to stand still and balanced. Most children with AS could not do this. Therefore, their weight was assessed using a wheelchair scale, and manually inserted (61%) - Participant did not tolerate swimming cap, thus measurement was conducted without swimming cap (57%) - Calibrating Ipad or stuffed animal into the BOD POD (for distraction; 22%)