A new tremor mutant in the Pietrain pig: an animal model of orthostatic tremor? Clinical and neurophysiological observations.

A new tremor mutant, the "Campus syndrome" was studied in a breed of Pietrain pigs. Affected pigs showed a coarse tremor of the extremities when standing and walking, so they tended to remain recumbent, during which the tremor was suppressed. Needle electromyographic recordings of the semitendinosus muscle plus accelerometry revealed a high-amplitude 14- to 15-Hz tremor pattern activated specifically upon standing but maintained during walking. The observed syndrome thus bears similarities to the human condition of orthostatic tremor and might serve as an animal model for this as yet poorly understood disorder.