Transient phonemic paraphasia by bilateral hippocampus lesion in a case of limbic encephalitis

Abstract

Although the hippocampus has not typically been identified as part of the language and aphasia circuit, recent evidence suggests that the hippocampus is closely related to naming, word priming, and anomic aphasia. A 59-year old woman with limbic encephalitis of possible autoimmune etiology, after recovery of consciousness, presented with severe memory impairment in both anterograde and retrograde modalities, episodes of fear, hallucination and convulsion, and transient fluent, phonemic paraphasia, together with small sharp waves diffusely by EEG. Brain MRI revealed bilateral symmetric, discrete lesions in the body to the infundibulum of the hippocampus.The transient phonemic paraphasia noted in our patient may have been a result of primary damage in the hippocampus and its fiber connection to the Wernicke's area or secondary partial status epilepticus that might have originated in the hippocampus.

Keywords: aphasia; epilepsy.; hippocampus; limbic encephalitis.

Figure 1

Brain magnetic resonance imaging of the patient. Bilateral, symmetrical high signal lesions localized in the body to the infundibulum of the hippocampus, which slightly extended to the parahippocampal gyrus and the amygdala on fluid attenuated inversion recovery (FLAIR) images. Coronal images are shown. Pre-existing mild malformation in the temporal neocortex was also noted.