Anomia with Amnesia Caused by Hemorrhage in the Left Anterior and Medial Thalamus: Thalamic Anomia Particularly for Artificial Objects

We herein report the case of a patient who showed pure anomia and amnesia caused by hemorrhage in the left thalamus, involving the anterior, ventral anterior, and mediodorsal nuclei. It was revealed that the anomia was characterized by impaired retrieval of object names, which was more pronounced in artificial objects, and abundant perseveration, whereas the amnesia was mild and limited to daily routine events, which was made clear from the results of an episodic memory scale. Detailed lesion localization and literature review revealed that a combination of pure anomia and amnesia can occur in a lesion involving the anterior, ventral anterior, or mediodorsal nucleus of the thalamus. The relative specificity to artificial objects can be explained by the locally damaged fiber connection to the putative category-specific lexical area in the temporal lobe.