Air-caloric delivery tube adapter.

This problem had also been noted with our early use of the air caloric stimulator. There were two apparent possible causes of the variability: (1) alteration in the temperature of the air as it passed through the delivery tube, caused by its temperature gradient with the ambient air in contact with the outer surface of the tube, and (2) test-to-test variation in the depth and orientation of the delivery tube during stimulation. It was demonstrated that positioning of the delivery tube can markedly affect the rate of heat exchange with the labyrinth. It was difficult for the technician to consistently maintain the position of the delivery tube tip at the appropriate depth in the ear canal during stimulation and, particularly, to precisely reproduce this placement in the same or other patients.