The Creutzfeldt-Jakob disease (CJD) neurological status scale: A new tool for evaluation of disease severity and progression

Objectives- To develop a scale sensitive for the neurological manifestations of Creutzfeldt-Jakob disease (CJD). Methods- A 26-item CJD neurological status scale (CJD-NS) was created based on characteristic disease manifestations. Each sign was assigned to one of eight neurological systems to calculate a total scale score (TSS) and a system involvement score (SIS). The scale was administered to 37 CJD patients, 101 healthy first-degree relatives of the patients and 14 elderly patients with Parkinson's disease (PD). Results- The mean TSS (±SD) was significantly higher in patients with CJD (13.19±5.63) compared with normal controls (0.41±0.78) and PD patients (9.71±3.05). The mean SIS was also significantly different between the CJD (5.19±1.22) and PD (2.78±1.18 P≤0.01) groups reflecting the disseminated nature of neurological involvement in CJD. Using a cutoff of TSS>4 yielded a sensitivity of 97% for CJD, and specificity of 100% against healthy controls. All individual items showed excellent specificity against healthy subjects, but sensitivity was highly variable. Repeat assessments of CJD patients over 3-9months revealed a time-dependent increase in both the TSS and the SIS reflecting the scale's ability to track disease progression. Conclusions- The CJD-NS scale is sensitive to neurological signs and their progression in CJD patients.