Pusher syndrome: its cortical correlate

Abstract

Unilateral stroke can lead to a disorder of postural balance that manifests as a pushing away toward the contralesional side. It is called "pusher syndrome" (PS). The aims of this study were first to assess the anatomical cortical regions that induce PS and second to clarify whether tilt of the subjective visual vertical (SVV)--a sign of vestibular otolith dysfunction--is associated with PS. Sixty-six patients with acute unilateral strokes (28 left-sided lesions, 38 right-sided lesions) were tested for PS, for tilts of the SVV, for hemineglect and for the anatomical lesion site by magnetic resonance imaging (MRI)-based voxelwise lesion-behavior mapping analysis. Our data indicated no significant voxels; however, there was a trend towards an association between lesions of the posterior part of the insula, the operculum and the superior temporal gyrus--key areas of the multisensory vestibular cortical network--and the extent of pushing in patients with right-sided lesions, whereas the rather anterior part of the insula, the operculum as well as the internal capsule reaching to the lateral thalamus seemed to be involved in PS in left-sided lesion patients. These data might point toward a link between the systems responsible for postural control and for processing vestibular otolith information. These findings indicate that vestibular information might be fundamental in right-sided lesion patients for maintaining body posture in space.

Pusher syndrome in patients with cerebellar infarctions?

“…Therefore, contrary to a cortical level where an association between PS and SVV tilt was reported [3,7] and points toward otolith dysfunction in PS patients, at a cerebellar level such an association could not be verified by our data. Indeed, one might even speculate that PS does not exist in cerebellar stroke patients.…”

“…Besides supratentorial lesions [1][2][3], there have also been claims of PS occurring in patients with cerebellar lesions [4]. Thus, we aimed to answer the question whether the PS can be found regularly in patients with cerebellar lesions.…”

Trunk Control and Lesion Locations According to Alberta Stroke Program Early CT Score in Acute Stroke: A Cross-Sectional Study

“…They found that right hemispheric lesions were associated with greater postural sway velocity, range and variability in standing with eyes closed as opposed to eyes open, compared to patients with left MCA lesions and controls. Other researchers [36][37][38] have also found that patients with right hemispheric lesions seem to display the poorest postural control. Abe et al [39] found significantly higher prevalence for pushing behavior, a disorder of the upright body orientation with respect to gravity [39,40], in patients with acute right hemispheric lesions as compared to left and thereby poorer postural control.…”

Subjective body vertical: a promising diagnostic tool in idiopathic normal pressure hydrocephalus?

“…The importance of the thalamus for postural control is further supported by the clinical syndrome of thalamic astasia [36,37] and the pusher syndrome [16]. The overlap area of infarctions in patients with a pusher syndrome was centered on the post-erolateral thalamus [16] or the posterior insula (in right-sided lesions) and the anterior insula (in left-sided lesions), thus affecting the thalamo-insular pathways [38,39] and parts of the postcentral gyrus [25]. This also agrees with a study which demonstrated that the post-erolateral thalamus was involved in resistance to the Aubert effect, i.e., the deviation of visual vertical estimates in the direction of body tilts [20].…”