Table 2.

Search queries used in Google Scholar and Web of Science for the three types of sensor and sensor fusion.

Sensor type	Query
Wearable-based	(Topic): ((“Fall detection" OR “Fall” OR “Fall accident”) AND (“Wearable” OR “Worn” OR “Accelerometer” OR “Machine learning” OR “Deep learning” OR “Reinforcement learning”) NOT “Survey” NOT “Review” NOT “Kinect” NOT “Video” NOT “Infrared” NOT “Ambient”)
Vision-based	(Topic): ((“Fall detection” OR “Falls” OR “Fall accident”) AND (“Video” OR “Visual” OR “Vision-based” OR “Kinect” OR “Depth camera” OR “Video surveillance” OR “RGB camera” OR “Infrared camera” OR “Monocular camera” OR “Machine learning” OR “Deep learning” OR “Reinforcement learning”) NOT “Wearable” NOT “Ambient”)
Ambient-based	(Topic): ((“Fall detection” OR “Falls” OR “Fall accident”) AND (“Ambient” OR “Ambient-based” OR “Ambience-based” OR “RF-sensing” OR “WiFi” OR “Cellular” OR “vibration” OR “Ambience” OR “Radar” OR “Machine learning” OR “Deep learning” OR “Reinforcement learning”) NOT “Wearable” NOT “vision”)
Sensor Fusion	(Topic): ((“Fall detection” OR “Falls” OR “Falls accident”) AND (“Health monitoring” OR “Multiple sensors” OR “Sensor fusion” OR “Sensor network” “Data fusion” OR “IoT” OR “Camera arrays” OR “Decision fusion” OR “Health monitoring” OR “Fusion” OR “Multiple sensors” OR “Machine learning” OR “Deep learning” OR “Reinforcement learning”))