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 3-9 months 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.