Subjective visual vertical (SVV) determined in a representative sample of 15 patients with pusher syndrome

Excerpt

Sirs: A recent study of Saj and colleagues [16] investigated the perception of the subjective visual vertical (SVV) in a small group of 4 subacute stroke patients with pusher syndrome following the development of a right hemisphere lesion. Hemiparetic stroke patients with “pusher syndrome” show the peculiar behavior of using the non-affected arm or leg to actively push away from the unparalyzed side [7, 11]. The disorder is associated with a severe misperception of the patient’s own upright body orientation, indicated by a marked lateral tilt of the subjective postural vertical (SPV) of nearly 20° [12]. Adjustment of the SPV reflects the perceived upright orientation of the body. Blindfolded subjects are seated on a lateral tilt chair that is passively tilted by the experimenter while subjects are immobilised by lateral stabilisation and indicate verbally or by button press when the chair brings their body in an ‘upright’ position [6, 15, 18]. The marked lateral SPV tilt in pusher patients indicates that these subjects are no longer able to determine when their body is oriented in an erect position. They misperceive their body as oriented ‘upright’ when actually tilted by nearly 20° to the side [12]. …