Table 1.

Brief overview of some of the advantages and disadvantages associated with various sensing modalities in the context of recording general movements in preterm infants.

		Advantages	Disadvantages
Indirect sensing	Video cameras (33, 36, 63)	1. Easy to understand	1. Computationally expensive analysis
		2. High spatial resolution	2. Privacy concerns
		3. High context information	3. Large disk space requirements
		4. Portable	4. Generally low temporal resolution
		5. High availability	5. Occlusion issues
	3D motion capture (29, 37)	1. High spatial resolution	1. High costs
		2. Depth information	2. Computationally very expensive analysis
		3. Accurate motion capture	3. Privacy concerns
		4. High reliability	4. Very large disk space requirements
		5. High temporal resolution possible	5. Large physical space requirement
		6. Secondary movement analysis possible (such as force and weight exchange)	6. Markers needed for motion capture
			7. Occlusion issues
	Microsoft kinect (35, 47, 62)	1. High spatial resolution	1. Not suitable for infants (<4 years)
		2. Depth information	2. Occlusion issues
		3. Low-cost	3. Low temporal resolution
		4. Marker-less motion capture	4. Limited field of view
Direct sensing	Wearable movement sensors (11–13, 34, 39–43, 45, 64)	1. High temporal resolution	1. Low spatial resolution
		2. Low-cost	2. Occasional data losses (wireless)
		3. Energy efficient	3. Limited battery life (wireless/real-time)
		4. Privacy preserving	4. Difficulty in consistent positioning
		5. Small physical size	5. Comfort issues
		6. Good battery life (embedded)	6. Relative movement capture only
		7. High availability (e.g., mobile phones)
		8. Actigraphs: sleep/wake patterns
	Magnet tracking system (31, 46, 66)	1. High temporal resolution	1. High costs compared with accelerometers
		2. Very high accuracy	2. Computationally very expensive analysis
		3. Metal tolerant	3. Complex setup
		4. No line of sight occlusions	4. Magnetic and electrical interference issues