Movement disturbances in the differential diagnosis of Creutzfeldt-Jakob disease.

Movement disturbances are common in dementia disorders and are a central feature of the clinical classification criteria of Creutzfeldt-Jakob disease (CJD). Polymorphism at codon 129 of the prion protein gene is known to determine the clinical picture of CJD. The frequency and characteristics of movement disturbances in other dementing disorders, such as Alzheimer's disease (AD), is barely known and leads to misdiagnoses. We investigated the occurrence and characteristics of movement disturbances in 143 patients neuropathologically confirmed with CJD (n = 100), AD (n = 29), dementia with Lewy bodies (DLB) (n = 7), or other diagnoses (n = 7). All patients had been referred with the differential diagnosis of prion disease. Ataxia and dysmetria were significantly more frequent in CJD than in AD or DLB patients, whereas hypokinesia was up to five times more frequent in AD or DLB (P < 0.05). Using an ordered logistic regression to identify constellations of movement disturbances, the diagnosis of CJD was likely in patients presenting ataxia but not hypokinesia. The reverse situation was statistically associated with AD. Ataxia and cogwheel rigidity were associated with valine-homozygosity and akinesia with methionine-homozygosity in the CJD patients. Our results indicate that the careful assessment of movement disturbances may be helpful in the differential diagnosis of Creutzfeldt-Jakob disease.