“…Summary of the learning approaches that have been developed and tested for automatic pain detection from facial expressions.Brahnam et al[79], Monwar and Rezaei[80], Brahnam et al[81], Lu et al[51], Ashraf et al[82], Lucey et al[83], Siebers et al[84], Nanni et al[85], Gholami et al[86], Monwar and Rezaei[87], Wei and Li-min[88], Lucey et al[18], Lucey et al[89], Werner et al[90], Chen et al[91], Khan et al[92], Pedersen[93], Neshov and Manolova[94], Rathee and Ganotra[95], Aung et al[27], Kharghanian et al[96], Roy et al[97], Rupenga and Vadapalli[98], Meawad et al[99], Alphonse and Dharma[100] …”