Otoloth-Ocular Function in Cerebellar Ataxia

To maintain visual stability during motions of the head and trunk, the central nervous system must generate appropriate compensatory eye movements. The otolith-ocular reflexes (OOR) are essential for gaze stabilisation during translational motions of the head. There are several lines of evidence that cerebellar dysfunction can afflict otolith mediated responses. In this study we want to evaluate for the first time otolith-ocular reflexes in a homogeneous group of cerebellar ataxias. 25 patients with a clinical diagnosis of autosomal-dominant cerebellar ataxia and a diagnosis of SCA-1,2,3,6 and 7 and 25 normal controls will participate in the study. To assess otolith-ocular function in patients and controls, linear acceleration will be produced with a parallel swing. Horizontal and vertical eye movements will be recorded with an infrared limbus tracking device. In summary, the goal of the present study is to determine the role of the cerebellum in otolith-ocular function, and to evaluate to what extent these reflexes are disturbed in patients with different genetic causes of cerebellar degeneration. Furthermore we want to find out whether quantitative otolith- ocular tests - in combination with advanced molecular genetic studies - may be useful in the classification of hereditary cerebellar ataxia syndromes. It is planned to establish the applied method as a standard tool in the investigation of patients with balance disorders at the Department of Neurology in Vienna.