Primary Graviceptive System and Astasia: Case Report and Literature Review

Abstract Purpose of ReviewAstasia refers to the inability to maintain upright posture during standing, despite having full motor strength. However, the pathophysiology and neural pathways of astasia remains unclear.Recent FindingsWe analyzed 26, including ours, non-psychogenic astasia patients in English literature. Seventy-three percent of them were man, 73% were associated with other neurologic symptoms and 62% of reported lesions were at right side. Contralateral lateropulsion was very common followed by retropulsion while describing astasia. Infarction (54%) was the most commonly reported cause. Thalamus (65%) was the most commonly reported location. Infarction being the mostly likely to recover (mean:10.6 days), while lesions at brainstem had longer time to recover (mean: 61.6 days).SummaryThe underlying interrupted pathway may be the primary graviceptive system, which composed of at least five unilateral and contralateral projection fibers from vestibular nuclei to thalamic nuclei, and thalamo-cortical projections including subcortical white matter tracts and cortical areas.