A mathematical model of caloric nystagmus

✍ Scribed by O. Bock; B. Bromm

• Publisher: Springer-Verlag
• Year: 1977
• Tongue: English
• Weight: 499 KB
• Volume: 27
• Category: Article
• ISSN: 0340-1200
• DOI: 10.1007/bf00357707

✦ Synopsis

A mathematical model is proposed to explain the rise of nystagmic eye movements in response to caloric stimulation of the external meatus. For this purpose, equations are set up to describe the physical processes involved in caloric nystagmus. The mathematical description of heat transport from the meatus to the lateral semicircular canal includes heat transmission through the meatus wall and heat conduction in the petrous bone. The influence of blood perfusion is taken into account as well as the greater heat conductivity of the bone situated between the external and internal edge o f the semicircular canal. The model is represented in Laplace notation, as is usually done in system modelling. The endolymph flow induced by a temperature gradient across the lateral canal, and the eye movements resulting from endolymph rotation are described by means of established models of other authors. Thus, the time-course of nystagmus can be computed for a given duration and temperature of caloric irrigation. The predicted nystagmus is in good agreement with experimental results of common clinical tests. Long-term stimulation results in complete adaptation in the model, whereas preliminary experiments suggest sustained nystagmus.