[Differential heat diffusion as a factor in the etiology of the caloric nystagmus phenomenon]

Despite the significance of the caloric vestibular test in clinical practice, the origin of the caloric nystagmus phenomenon is still unclear. Several theories which try to explain the functional pathways have been published. However, the bandwidth of the reaction pattern and response times from the start of stimulation to the first responses question their plausibility. Therefore, the present investigation examines and analyses the specific reaction pattern and associated response times in 84 patients. On the basis of this information a simplified computer simulation model involving lumped tissue parameters has been created to study the heat diffusion process during stimulation. Consequently, an attempt was made to utilize the simulated diffusion times to identify those anatomical structures which could participate in the origin of the caloric nystagmus phenomenon and we developed a new hypothesis about its origin.