Vestibular Physiology in a Strain of the Waltzing Guinea Pig

Abstract

The vestibular physiology was studied in a strain of the waltzing guinea pig with a dominant mode of inheritance. Rotation did not elicit any nystagmus response, and tilting failed to evoke counter-rolling of the eyes. In young waltzers a caloric response could be elicited by combining an immediately preceding fenestration of a semicircular canal with irrigation of the bulla with hot and cold water. No such reaction occurred in older animals. All waltzers showed impaired performances in behavioural tests for swimming ability and righting reflex, irrespective of age. The galvanic response was normal at any age. Scarpa's ganglion had a normal appearance when examined under the light microscope. The conclusions drawn are: that the waltzers of this strain are born with a decreased vestibular capacity, and that this impairment is progressive, presumably until total loss of function. The results are in agreement with earlier reports on the vestibular morphology, showing progressive neuroepithelial degeneration.