[Value of smooth pursuit evaluation within the scope of clinical computerized nystagmography]

Testing gaze movements is very important for the detection of central vestibular diseases. The intent of this study was to clarify the pathological importance of partially disturbed and completely disturbed smooth pursuit movements. One hundred patients were analyzed and curves of smooth pursuit movements were classified into three groups of different deformations: i.e, regular, partially disturbed and completely disturbed movements. The correlation index of each curve was then calculated. In 16 patients qualitative analysis showed a completely disturbed result in the smooth pursuit test. Nine of the patients (56.3%) showed morphological signs of a central disease. Twenty-nine patients yielded a partially disturbed test result and in 2 of them (6.9%) a central pathological illness was uncovered. Patients with completely disturbed smooth pursuits showed the highest average binocular correlation index (1.44). Others with partially disturbed results gave an index of 1.24, while persons with regular smooth pursuits yielded a value of 1.17. Because of the scattering seen, it was not definitely possible to attach a correlation index to central disease. On the other hand, an index higher than 1.3 should arouse suspicion for a central illness. Only completely disturbed smooth pursuit movements frequently appear in connection with central diseases. As a rule, a partially disturbed result does not indicate diseases of the central nervous system.