Although FDBSs arehighly specific to anti-LGI1 encephalitis, they precede the onset of cognitivesymptoms by weeks in 40-71% of patients.11,22,23 For this reason, FBDS are a clue to earlydiagnosis and immunotherapy with further prevention of cognitive decline anddementia.24 The gene discussed is LGI1; the disease is viral encephalitis.