The clinical manifestations and examination results of a case of Creutzfeldt-Jakob disease (CJD) admitted to the Department of Neurology of Peking Union Medical College Hospital,Chinese Academy of Medical Sciences in August 2020 were analyzed, and a comprehensive neuropsychological assessment and assessment of apraxia were conducted. The neuropsychological characteristics of apraxia in CJD patient and the progress in the research and evaluation of apraxia were reviewed. The patient was a 65-year-old male with insidious onset and progressive symptoms, whose clinical manifestations were apraxia, rapidly progressing dementia, and extrapyramidal symptoms. The magnetic resonance imaging showed hyper-intense signal in diffusion weighted imaging in bilateral cerebral hemispheres, and 14-3-3 protein in cerebrospinal fluid was positive, which were consistent with the probable CJD diagnostic criteria. The patient exhibited prominent signs and symptoms of ideomotor apraxia. It has been reported in the literature that apraxia can also be the main neuropsychological manifestation of CJD. It is necessary to pay attention to the standard evaluation and timely identification of apraxia in clinical diagnosis.

Objective: To evaluate the value of cerebrospinal fluid markers expecially total-tau protein (T-tau), phosphorylated-tau protein (P-tau) in diagnosis and differentiation of sporadic Creutzfeldt-Jakob disease (sCJD). Methods: sCJD (according to 2009 Brain criteria, 2018 Neurology amended criteria), Alzheimer's disease (AD; the National Institute on Aging at National Institutes of Health and the Alzheimer's Association revised guidelines 2011 criteria) and other patients without cognitive impairment, matched for sex and age, in the Department of Neurology, Peking Union Medical College Hospital from 2018 to 2019 were enrolled. Twelve sCJD patients, 49 AD patients and 14 normal controls were enrolled. Cerebrospinal fluid (CSF) specimens were collected through gravity dropping directly, and further stored in -80 ℃ and disposed according to widely used standards. The levels of T-tau and P-tau were measured by ELISA. The data on electroencephalogram and neuroimaging findings of sCJD patients were recorded. Moreover, specimens of sCJD patients were sent to the Chinese Center for Disease Control and Prevention to test 14-3-3 protein and PRNP genotype. Results: Using Mann-Whitney U test, T-tau concentrations were found higher in patients with sCJD (1 211(448, 2 227) pg/ml) than in AD patients (549(314, 1 078) pg/ml; U=178, P=0.034 9), and both groups had higher T-tau than the control group (127(79, 192) pg/ml; U=20, 73, P<0.01). The level of P-tau was significantly increased in AD patients (72(58,109) pg/ml) compared to the control group (27(15, 42) pg/ml; U=82, P<0.01), but not in sCJD patients (32(24, 47) pg/ml). The T-tau/P-tau ratio was higher in sCJD patients (29.77(20.01, 54.53)) than in AD patients (7.45(4.79, 10.43); U=87, P<0.01). Twelve sCJD patients had cotical hyperintensity on diffusion weighted imaging and five had periodic three-phase waves on electroencephalogram. Nine sCJD patients, whose CSF samples were tested in the Chinese Center for Disease Control and Prevention, carried an M/M genotype at codon 129 and E/E at codon 219. Conclusion The CSF tau level and T-tau/P-tau ratio are significantly increased in sCJD, which may promote the diagnosis and differentiation of sCJD in routine clinical setting.