Table 1.

Workup completed for cognitive decline and hemichorea including laboratory, imaging, and EEG testing.

Test category	Components	Result
Basic serum labs	CBC, BMP, LFTs, electrolytes	Normal
CSF labs (2×)	Protein, glucose, cell counts, IgG synthesis rate, IgG index, oligoclonal bands	Normal
Antiphospholipid antibodies (4× serum)	B2‐glycoprotein‐1 IgG/IgM, cardiolipin IgG/IgM	Positive cardiolipin IgM (70.7 MPL) once during relapse, negative on repeat twice
Autoimmune encephalopathy antibodies (2× serum, 3× CSF)	AGNA‐1, AMPAR, Amphiphysin, ANNA‐1, ANNA‐2, ANNA‐3, CASPR2, CRMP‐5, DPPX, GABA‐B, GAD65, GFAP, GlyR, IgLON5, KLHL11, LGI1, mGluR1, NIF, NMDA, Ma, PCA‐1, PCA‐2, PCA‐Tr, Ta. Serum Thyroglobulin, TPO	Serum anti‐GAD65 mildly elevated (0.03 nmol/L) once during remission, negative on repeat. All other tests normal
Rheumatologic labs	ANA, C3, C4, CRP, ESR, dsDNA, anti‐La, anti‐Ro, RHF, anti‐RNP, anti‐Scl‐70, anti‐Sm	ANA 1:40; All other tests normal
Dementia lab evaluation	B12, ceruloplasmin, HIV, syphilis, TSH, CSF A‐beta 42, CSF T‐tau, CSF P‐tau	Indeterminate Alzheimer's profile with reduced CSF A‐beta 42 to T‐Tau index and normal CSF P‐Tau; All other tests normal
Imaging	Brain MRI (2×), brain FDG‐PET (2×)	No infarct or mass; scattered hypometabolism in right anterior temporal lobe on initial PET; development of progressive frontotemporal atrophy with frontotemporal hypometabolism on 2‐year interval scans
EEG (2×)	Routine EEG	Normal