Damage to Hippocampus Can Linger in Encephalitis Patients

WEDNESDAY, March 14 (HealthDay News) -- Among amnesia patients with encephalitis associated with antibodies to voltage-gated potassium channels (VGKC), immunotherapy can help recover retrograde memory, but magnetic resonance imaging suggests that anomalies linger in the hippocampus, researchers report in the March issue of Archives of Neurology.

Dennis Chan, Ph.D., of the Royal Sussex County Hospital in Brighton, England, and colleagues conducted various cognitive tests before and after immunotherapy on three patients with encephalitis associated with VGKC.

Using regular neuropsychological tests, a public events test and a famous faces test, the researchers found that all three patients had experienced temporally ungraded retrograde amnesia for at least 20 years.

Magnetic resonance imaging showed high-signal abnormalities of the hippocampus in each patient. Immunotherapy seemed to cause some amelioration, but retrieval of remote memories did not show improvement over time.

"Encephalitis associated with VGKC results in extensive and temporally ungraded retrograde amnesia that is partially reversible with immunotherapy," the authors write. "Magnetic resonance imaging high-signal abnormalities were primarily restricted to the hippocampi. These data are supportive of theories postulating a role for the hippocampus in the storage and retrieval of all past memories, irrespective of age."

Abstract
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