10">We present a case of voltage-gated potassium channel (VGKC) antibody (Ab) syndrome, which is a form of autoimmune, non-paraneoplastic encephalitis that presents with acute or subacute memory loss, confusion, agitation, and psychiatric symptoms.

15">Patients with VGKC Ab syndrome may also present with symptoms mimicking a primary sleep disturbance such as severe insomnia and/or rapid eye movement (REM) sleep behavior disorder (RBD).

Increased awareness of this condition is important as it can be quickly diagnosed by a serological test and is typically responsive to treatment.