Table 2.

The relation between methodologies and the sensors used.

	Sensors															Methodology
Studies	Accelerometer	Gyroscope	Piezoelectric Strain Sensor	Magnetometer	Electroglottograph	Camera	Acoustic Sensor	Piezoelectric Respiratory Belt	Hand Gesture Sensor	Electrocardiogram	Ultrasonic Doppler	Flex Sensor	Photoplethysmography	Dermal Activity	Temperature Sensor Array	Convolutional Neural Network	Deep Neural Network	Support Vector Machine	Artificial Neural Network	J48	Naive Bayes	Swallow Net	Short-Time Fourier Transforms	TensorFlow	Restricted Boltzmann Machine	Belief Net	Markov Hidden Model	Long Short-Term Memory	Gaussian Processes	Connectionist Temporal Classification Loss
Bahador et al. [23]													X	X	X		X
Doulah et al. [24]	X					X						X						X
Heydarian et al. [25]						X											X
Kyritsis et al. [27]	X	X														X												X		X
Lee [30]											X					X											X
Mamud et al. [31]	X	X					X
Mirtchouk and Kleinberg [32]							X										X												X
Rouast and Adam [33]						X											X
Fuchs et al. [34]						X	X
Heremans et al. [35]										X									X
Hossain et al. [36]						X										X
Rachakonda et al. [37]						X
Sundarramurthi et al. [38]						X										X
Ye et al. [40]						X										X
Farooq et al. [42]			X						X								X
Johnson et al. [43]	X	X		X														X
Konstantinidis et al. [44]						X											X
Kumari et al. [45]							X																		X	X
Park et al. [46]																X								X
Qiu et al. [47]						X										X
Raju et al. [48]						X
Turan et al. [49]							X									X							X
Wan et al. [50]						X										X
Lee [51]							X
Nguyen et al. [52]	X	X	X	X																		X
Papapanagiotou et al. [53]						X	X									X
Farooq et al. [54]			X																X
Farooq et al. [55]					X	X											X		X								X
Dong et al. [56]								X										X		X	X
Pouladzadeh et al. [57]						X												X