Table 1.

Diagnostic findings, initially (2009/10) and at follow-up (2019).

Investigation	Initial findings (2009/2010; [9])	Follow-up findings (2019)
Basic blood analyses	Glutamate pyruvate transaminase (GPT) was elevated (70 U/l; reference 10–35 U/l), γ-glutamyl transferase (γ-GT) was elevated (72 U/l; reference 0–40 U/l), other liver values were normal. Thyroid-stimulating hormone was elevated (4.77 µU/ml; reference 0.27–4.20 µU/ml), triiodothyronine, and thyroxine levels were in normal range.	Normal liver values. Thyroid-stimulating hormone, triiodothyronine, and thyroxine levels were in normal ranges. Vitamin B12/D, folic acid and selenium were normal.
Antibody findings	Screening for antibodies against neuronal cell surface antigens showed IgG antibodies against the NMDA-R (NR1-subunit; in the reference laboratory in Oxford using a live cell-based assay). Antibody against SOX1 were non-specifically slightly positive. Autoantibodies against TSH-receptor (TRAK) were elevated (4.77 µU/ml; reference 0.27–4.20 µU/ml), autoantibodies against thyroglobulin and thyroid peroxidase were normal. No screening for other immunological/rheumatological alterations was conducted.	Antibodies against different neuronal cell surface antigens (AMPA-R, DPPX, GABA-B-R, LGI1, Caspr2, and NMDA-R) were negative in serum (using biochip-assays from Euroimmun®). No antibodies against the intracellular onconeural antigens Yo, Hu, CV2/CRMP5, Ri, Ma1/2, SOX1, Tr(DNER), Zic4, or the intracellular synaptic antigens GAD65/amphiphysin were found (using Ravo line assay®). Autoantibodies against thyroglobulin, TSH receptor and thyroid peroxidase were not increased. Screening for antinuclear antibodies (ANA) showed a slightly positive homogenously result against nucleus and chromosomes (HEp-2), AMA/LKM, and anti-DFS70 were borderline positive (+). Anti-neutrophil cytoplasmic antibodies, antiphospholipid antibodies, rheumatoid factor, and anti-mitochondrial antibodies were negative. CH50 was slightly increased (131, reference: 65-115%), no other changes in the complement system (C3, C4, CH50, C3d) were observed. Normal serum IgA, IgM und IgG immunoglobulin concentrations; immunofixation showed no monoclonal antibody production. Anti AQP4-IgG and MOG-IgG antibodies were negative.
Cerebrospinal fluid analyses	Initially slight pleocytosis (23 µl; reference <5/µl). In the course normal white blood cell count (1/µl; reference <5/µl). Slightly elevated protein concentration (561 mg/L; reference <450 mg/L), and elevated age-corrected albumin quotient: 8.7; age-dependent reference <6.5 × 10−3) No CSF-specific oligoclonal bands; IgG index not increased (0.53; reference ≤0.7).	No lumbar puncture was conducted.
Cerebral magnetic resonance imaging with combined volume- and region-based analysis method (CVR) analysis	Inconspicuous findings, especially for the hippocampal regions and in the structures of the limbic system. Enlargement of the lateral ventricles with emphasis on the posterior horns and slight striatal and insular atrophy.	Except for a few non-specific right-frontal white matter lesions, the findings were essentially unchanged.
Electroencephalography – visual assessment	Intermittent delta focus over the right central areas.	Occipital α-activity (11 Hz).
Independent component analyses	1) Right and left frontotemporal delta waves; 2) a deep right temporal generator; and 3) a central component with theta frequencies.	Left-side spike-wave activity and intermittent rhythmic delta activity.
[18F]fluorodeoxyglucose positron emission tomography	Global cortical hypometabolism of the left hemisphere and right-temporal accentuation was detected. Cerebellar hypometabolism predominantly on the right side (most likely indicating crossed cerebellar diaschisis).	Not performed.
Cardiovascular examinations	Inconspicuous resting electrocardiography. Inconspicuous transthoracic echocardiography.	Inconspicuous resting electrocardiography. Raised long-term blood pressure.
Neuropsychological testing	Slower reaction times with evidence for heightened irritability and severely impaired ability to increase attention. Considerable amount of missings and errors in divided attention task. Severe deficits in cognitive flexibility. Considerable amount of missings and errors in working memory task	Slower reaction times with retained ability to increase attention. Considerable amount of missings and mean level of errors in divided attention task. Moderate deficits in cognitive flexibility. Considerable amount of missings and mean level of errors in working memory task