TABLE 5.

Current guidelines for sCJD diagnosis.

Diagnostic	Signals and symptoms
	∗WHO, 2003	∗∗CDC, 2018
Possible	Progressive dementia; AND at least two of the following four clinical features: myoclonus, cerebellar or visual disturbance, pyramidal/extrapyramidal dysfunction, akinetic mutism; AND unknown or atypical EEG; AND disease duration less than two years.	Progressive dementia; AND at least two of the following four clinical features: myoclonus, cerebellar or visual disturbance, pyramidal/extrapyramidal dysfunction, akinetic mutism; AND no positive result for any of the four tests that would classify a case as “probable”; AND disease duration less than two years; AND no alternative diagnosis from routine investigations.
Probable	Progressive dementia; AND at least two of the following four clinical features: myoclonus, cerebellar or visual disorder, pyramidal/extrapyramidal dysfunction, akinetic mutism; AND typical EEG regardless of disease duration; AND/OR positive CSF 14-3-3 assay and disease duration to death less than two years; AND no alternative diagnosis from routine investigations.	Neuropsychiatric disorder and positive RT-QuIC in CSF or other samples; OR rapidly progressive dementia and at least two of the following four clinical features: myoclonus, cerebellar or visual disorder, pyramidal/extrapyramidal dysfunction, akinetic mutism; AND a positive result on at least one of the following tests: typical EEG regardless of disease duration, positive CSF 14-3-3 assay with disease duration less than two years, high signal in caudate/putamen on MRI brain scan or at least two cortical regions (temporal, parietal, occipital) either on DWI or FLAIR; AND no alternative diagnosis from routine investigations.
Definite	Neuropathological confirmation; AND/OR detection of resPrP by immunochemistry or immunoblotting; AND/OR observation of PrPSc fibrils.	Neuropathological confirmation; AND/OR detection of resPrP by immunochemistry or immunoblotting; AND/OR observation of PrPSc fibrils.

^∗Reference: Brown et al. (2003). ^∗∗Reference: CDC’s Diagnostic Criteria for Creutzfeldt-Jakob Disease (CJD), 2018.