Thalamic astasia from isolated centromedian thalamic infarction

Abstract

In thalamic astasia a unilateral thalamic lesion causes postural instability or retropulsion or lateropulsion.1 In previous reports, the responsible lesions have been localized in the posterolateral thalamic area. In contrast to patients with pontomesencephalic lesions, patients with thalamic astasia did not exhibit the clinical signs of ocular tilt reaction.2 Furthermore, the assessment of static graviceptive function by means of the subjective visual vertical (SVV) revealed ipsiversive as well as contraversive deviations of the SVV in these patients.2 We describe a patient with thalamic astasia due to a highly selective unilateral centromedian thalamic lesion. An 82-year-old man with acute onset of astasia with body lateropulsion to the right was admitted to our hospital. Neurologic examination was otherwise normal. MRI disclosed an acute selective ischemic lesion in the left centromedian thalamus (figure). No further brain lesions were detected. An experienced neuroradiologist localized the exact anatomic lesion site using sections from a stereotactic atlas of the human thalamus.3 Figure Cerebral MRI and schematic horizontal thalamic section Axial diffusion-weighted imaging sequence of cerebral MRI shows a small hyperintense lesion with 5-mm diameter in the centromedian part of the left thalamus (left). The correlating lesion site is labeled in …