TABLE 1.

Standard operating procedures informed by the formative phase of this study.

Study component	Challenges	Solutions
Consenting	Hesitancy due to unfamiliarity with EEG	Showing the EEG equipment to families and allowing them to hold and examine the device
		Showing small video clips of sample EEG assessments to family members
	Hesitancy in the mother to provide consent before consulting with other family members, especially the father	Ensuring that all available family members were involved in the consent process
		Leaving a collage of images illustrating the EEG assessment (see Supplementary Figure 1) in the household so absent family members could be informed about the assessment
Child engagement strategies	Children were intimidated by the headset	The EMOTIV EPOC device was decorated with stickers to make it colorful and attractive (see Figure 1B)
	Children hesitated to wear the headset	The animated video on the DEEP cognitive assessment tool (Bhavnani et al., 2019) contained a scene in which the protagonist (the child) wears a helmet-like headset before starting an exciting journey (see video snapshot in Figure 1B). Assessors played the video to engage the child, and paused it when the protagonist wore the helmet to encourage the participating child to wear a headset like the character in the video. They were told they could continue on their journey through the cognitive assessment game after wearing the headset
		The assessors wore the headset themselves, or requested the mother to do so briefly
Data collection protocols	Children were reluctant to close their eyes	Children were allowed to cover their eyes using their hands, or the caregiver or assessor could do so for them
	Due to the uncontrolled nature of the setting, disturbances were anticipated during data collection	Data collection was conducted in a separate room with only the primary caregiver(s) and the child in the household to minimize disturbances
		Assessors were trained to record the time stamps of any disturbance that led to visible changes in the EEG signal recording (example trace in Figure 2)