A closed-flow water caloric system.

This paper describes a new method and apparatus to induce nystagmus. Flow of fluid into the ear to induce nystagmus is eliminated by utilization of a closed-flow system. A probe adapted for insertion to a standardized depth into the ear, provides a flow-through path for nystagmus-inducing liquid while expanding in response to the pressurized liquid to conform to the contours of the external auditory canal and tympanic membrane. Thermal conductivity through the membrane-like probe material permits heat exchange between the flowing liquid, and the external auditory canal and/or tympanic membrane to induce nystagmus.At this time, the authors can state only that the quality of nystagmus produced is similar to that produced by current conventional methods. In the small number of patients tested, discomfort appeared to be almost negligible. The system appears to be a promising improvement dependent on the establishment of accurate parameters for diagnosis.