As stated in the Webster's 1913 definition, Hysteria can bring rise to imaginary sensations. One method of demonstrating that somebody has Hysteria is by proving that some sensation the patient reports is physiologically impossible.
A classic way of doing this requires a tuning fork. The medical practitioner strikes the fork and presses the handle sequentially to two points on the patient's head: about six inches above each eye on the top of the head. The patient might report that they hear the fork louder in one ear than in the other. If they are not hard of hearing, this is impossible, and they have Hysteria. The reason for this is that the sound generated by the tuning fork is not heard via normal air conduction, but rather by bone conduction. The skull is a solid bone, which enables it to conduct sound more proficiently than air. In air conduction, the sound dissipates quickly and it is understandable that something heard in one ear might not be heard at all in the other. Given the nature of bone, however, the sound waves are conducted at equal intensity to the sound sensing cochlear nerves of both ears. As such, a person should hear the fork at equal volumes in both ears both times the fork is applied.
Hysteria is what Sigmund Freud would call a conversion or somatization disorder, wherein the patient suffers psychological stress which manifests itself as a physical problem. The term Hysteria is actually rather vague, and refers to a broad category of disorders called hysterical disorders. Sometimes, actual physical disorders are present, which must be ruled out before making the diagnosis of a hysterical disorder. Some of these disorders may be diagnosed if a patient reports numbness in only one limb or part of a limb. Similarly, various clinical inventories may be used to predict hysterical tendencies.
For better or for worse, these illnesses tend to manifest in vastly different ways. Keep in mind, therefore, that if you suspect somebody of having a Hysterical disorder, tapping them on the head with a tuning fork is not guaranteed to prove anything.