EEG Observations in Probable Sporadic CJD

Sporadic Creutzfeldt Jakob Disease, the most common reported prion disease, is a fatal neurodegenerative disease caused by the misfolding of protein PrP^C to PrP^SC. EEG is the first in vivo test to support the clinical diagnosis of sporadic CJD (sCJD). This study is carried out to describe the comprehensive electroencephalography changes in a cohort of patients with probable sCJD from south India.

This retrospective observational study is conducted by reviewing case records from 2013-2020. Demographic, clinical, imaging details were noted. Electroencephalogram (EEG) recordings were retrieved and reviewed independently by two qualified epileptologists and the findings were visually analyzed and correlated with clinical and imaging abnormalities.

Fifty patients with probable sCJD with the availability of artefact-free EEG were included in the study. The mean age was 59.76 ± 8.17 years and M: F was 31:19. Magnetic resonance imaging (MRI) brain showed abnormality defining CJD in 48/50, i.e., 96%patients. EEG showed specific and or nonspecific abnormalities in 88%. The specific abnormalities, i.e., periodic sharp wave complexes (PSWC), were noted 66%. PSWC were mostly asymmetric (90%) and more frequently seen in the right hemisphere (57.6%). Amplitude maximum in the occipital region was noted in 42.4% and in frontal region in 36.4%. The sensitivity of EEG specific abnormalities to diagnose probable sCJD according to CDC 2018 criteria with positive MRI findings was 68.75%.

This study showed that EEG is a relatively inexpensive and sensitive tool and assists in the diagnosis of sCJD. However, it can be normal or show nonspecific abnormalities in the early stages of the disease.