Mortar explosion: Hysterical deafness.
A young soldier, a peasant, fell down unconscious when a mortar exploded killing several men. He regained consciousness a few hours later but was deaf on both sides. He looked dazed and did not spontaneously move, having to be called for meals. Communicating by writing, he could tell all the details of the accident.
The laryngeal and corneal reflexes were absent and there was a hyperesthesia and hypalgesia of the right side of the body. No anatomical basis for the deafness could be determined.