Acute anterograde amnesia by infarction of the mamillothatamic tracts

We report a case of persistent anterograde amnesia secondary to an anterior thalamic infarct. A 49-year-old right-handed man is referred for acute anterograde amnesia. Diffusion-weighted imaging performed at 24 hours shows an acute punctiform infarct of the left anterior thalamus, white T2-weighted imaging reveals a contralateral and symmetrical ischemic sequelae in the right anterior thalamus. The two Lesions are isolated and remarkably centered with the mamillothalamic tract. We suggest the symptoms are caused by the addition of the two lesions interrupting the mamillothalamic tracts. This is the second clinicopathological observation of a persistent amnestic syndrome secondary to a bilateral lesion of the mamillothalamic tract. (c) 2007 Elsevier Masson SAS. Tous droits reserves.