Video NeuroImages: Head titubation in anti-mGluR1 autoantibody-associated cerebellitis

A 39-year-old woman presented with apathy, catatonia, and continuous large-amplitude oscillatory head movements (head titubation) evolving over 1 month (video, [links.lww.com/WNL/A353][1]). Severe ataxia developed weeks later. Brain MRI, EEG, and serologies were normal. Cell- and tissue-based assays were positive for anti–metabotropic glutamate receptor 1 (mGluR1) antibodies (serum 1:12,800, CSF 1:512; figure). Head titubation, a slow-frequency cerebellar outflow tremor of the head associated with axial hypotonia, may appear in cerebellar abnormalities (Joubert syndrome, Dandy-Walker syndrome) or disorders affecting the anterior lobe of the cerebellum.1 Subacute head titubation should raise suspicion for an mGluR1-associated autoimmune cerebellitis, especially if associated with psychiatric changes.2 [1]: http://links.lww.com/WNL/A353