Le 15/10/2021 de 13:30 à 15:30
L'homme contre la gravité: les réseaux cérébraux de la graviception étudiés à partir de 170 individus post AVC
Camille Lemaire (Grenoble, France), Céline Piscicelli (Grenoble, France), Shenhao Dai (Grenoble, France), Olivier Detante (Grenoble, France), Monica Baciu (Grenoble, France), Dominic Perennou (Grenoble, France)
Objective : Lateropulsion is a postural behavior frequently observed after hemisphere stroke and considered as a trinity associating : lateral body tilt, spontaneous active pushing, and resistance to passive corrections. Better knowing which structures of the cerebral hemispheres, when damaged, induce a lateropulsion is a way to explore neural bases of the graviception. Surprisingly few studies have investigated these mechanisms, and none comprehensively with careful analyses of grey and white matter on a large series of individuals. This is the objective of this study.
Material / Patients and Methods : This is a large cohort of 170 individuals (80 rights, 90 lefts) with both MRI and an evaluation of lateropulsion (with SCP scale), in a subacute stage after a first hemisphere stroke. To analyze relationships between lateropulsion and damaged structures, same procedure was run for grey matter (from lesions’ drawing) and white matter (from disconnectome maps computed on BCBtoolkit sofware). This procedure was based on mass univariate voxel-based lesion-symptom mapping.
Results : VLSM analysis reveals a strong association between lateropulsion and several key structures of the right hemisphere. For the grey matter were strongly involved, the putamen, the posterior insula and the caudate nucleus. For the white matter the study revealed a dramatic alteration of thalamo-insular projections, with alterations of cortico-spinal tract and internal capsule. No structure of the left hemisphere was significantly associated with lateropulsion.
Discussion - Conclusion : These brain structures contribute to the construction and updating of the sense of the upright and support the motor command. A better understanding of the neuroanatomical basis of lateropulsion could help shape novel interventions.
Keywords : Lateropulsion, Voxel Lesion Symptom Mapping, Neural correlate, Disconnection syndrom, postural disorder