Electrical stimulation of the human body can be applied to restore bodily functions. Notable examples are auditory and visual prostheses to make the deaf hear and the blind see, and functional electrical stimulation to make the limp walk. It can be used for diagnosis (e.g., electromyography). Also, electrical stimulation can be used to treat (mental) illnesses (electrotherapy). Lastly, it can be the cause of injuries (e.g., due to a lightning strike).