Posterior thalamic hemorrhage induces "pusher syndrome".
BACKGROUND
Recent findings argue for a pathway in humans for sensing the orientation of gravity and controlling upright body posture, separate from the one for orientation perception of the visual world. Stroke patients with contraversive pushing were shown to experience their body as oriented upright when actually tilted about 20 degrees to the ipsilesional side, in spite of normal visual-vestibular functioning. A recent study suggested the involvement of posterolateral thalamus typically associated with the disorder.


OBJECTIVE
To evaluate the relationship between pushing behavior and thalamic function.


METHODS
Over a 3-year period the authors prospectively investigated 40 patients with left- or right-sided thalamic strokes.


RESULTS
Twenty-eight percent showed contraversive pushing. The authors found a strong relationship between etiology, vascular territory, lesion size, and neurologic disorders associated with contraversive pushing. Pusher patients had larger lesions that typically were caused by hemorrhage (vs infarcts) located in the posterior thalamus (vs anterior thalamic lesions in those patients without pushing behavior). A paresis of the contralesional extremities was more frequent and more severe in pusher patients. Further, these patients showed more additional spatial neglect with right thalamic lesions, while they tended to be more aphasic with left thalamic lesions.


CONCLUSIONS
Posterior thalamus seems to be fundamentally involved in our control of upright body posture. Higher pressure, swelling, and other secondary pathologic processes associated with posterior thalamic hemorrhage (vs thalamic infarction) may provoke contraversive pushing in combination with additional neurologic symptoms.
Karnath
Hans-Otto
HO
Section Neuropsychology, Department of Cognitive Neurology, Hertie-Institute for Clinical Brain Research, Tübingen, Germany. Karnath@uni-tuebingen.de
Johannsen
Leif
L
Broetz
Doris
D
Küker
Wilhelm
W
D000368:Aged; D001132:Arm / Q000294:innervation / Q000503:physiopathology; D020520:Brain Infarction / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D020300:Intracranial Hemorrhages / Q000150:complications* / Q000175:diagnosis; D007866:Leg / Q000294:innervation / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D009434:Neural Pathways / Q000503:physiopathology; D009949:Orientation / Q000502:physiology; D010291:Paresis / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D020656:Posterior Thalamic Nuclei / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D004856:Postural Balance / Q000502:physiology; D011446:Prospective Studies; D013786:Thalamic Diseases / Q000175:diagnosis / Q000503:physiopathology*; D014057:Tomography, X-Ray Computed