Persistent pure verbal amnesia and transient aphasia after left thalamic infarction.

A 57-year-old right-handed man suffered persistent pure verbal amnesia (PPVA) and transient aphasia after left thalamic infarction. A neuroanatomical study with magnetic resonance imaging to identify the site of the lesion showed destruction of the internal medullary lamina (IML), mammillothalamic tract (MTT), the ventrolateral nucleus (VL) and the lower one-third of the medial nucleus. As regions critical for PPVA are unknown, we reviewed the cases of PPVA after left thalamic infarction reported in the literature. These suggest that confined destruction of the IML, MTT and VL in the left thalamus can produce PPVA.