[Left paramedian thalamic infarct. Memory and language study]

Unusual findings in a patient with a paramedian infarct of the left thalamus, shown by CT scan were the elective nature and long duration of memory disorders. Mild amnesia has been relatively stable for two years, and is apparent during tests as an anterograde verbal memory deficiency for all modalities (serial, associative, logical), without facilitation during learning or recall by semantic or phonologic cues. On the other hand, anterograde visual, gestual or tactile memory, and particularly retrograde verbal and visual memory are well retained. The worsening effect of verbal interferences on word learning is emphasized, whereas no similar phenomenon has been observed for visual material. The antero-internal thalamic lesion in the dominant hemisphere results in a memory disorder of a particular type which cannot be explained by the cognitive disorder, or by the very transient initial aphasic disturbance. Prolonged verbal amnesia with persistent reduction in fluency most probably results from a deficiency of specific incitation in using and memorizing verbal material, without other negligence phenomena. The role of the thalamocortical and particularly frontocingular connections are discussed, according to the semiology.