Clinical assessment of vertical supranuclear gaze palsy. During the neurological evaluation of eye movements, assessing eye pursuit movements alone (left) is insufficient: voluntary saccades must be tested (right). The examiner should require the subject to visually fixate on two separate objects, e.g. the examiner’s finger and a hatpin, which are displaced first horizontally and then vertically (up and down), but always within the subject’s visual field. The subject is then asked to look at each object alternately.