In some cases of head injuries, the cerebrum may be affected. this type of injury could cause a loss of

You can lose your sense of coordination, your inability to judge distances, and could cause staggering.

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.