OCULOMOTOR ABNORMALITIES IN MOTOR-NEURON DISEASE

To determine whether there are oculomotor abnormalities in motor neuro n disease (MND), electro-oculographic recordings were performed prospe ctively in 16 MND patients and the results compared with age-matched h ealthy controls. Parameters analysed included random and fixed saccade s (latency, velocity and accuracy), smooth pursuit (gain, total harmon ic distortion and number of saccadic intrusions) and optokinetic nysta gmus (maximal and mean slow component velocity). Increased saccadic la tencies and decreased smooth pursuit gain were the main alterations in the MND group. Correlation with clinical variables showed a positive relationship between smooth pursuit saccadic intrusions and the bulbar clinical score and the rate of progression and a lower optokinetic ny stagmus maximal velocity in patients with pseudobulbar syndrome. Our r esults demonstrate the presence of subclinical supranuclear abnormalit ies in MND, and support the notion that MND is not merely a degenerati on of the motor system.