CSF-neurofilament and levodopa tests combined with discriminant analysis may contribute to the differential diagnosis of Parkinsonian syndromes

The differentiation between Parkinson's disease (PD), progressive supranucl ear palsy (PSP) and multiple system atrophy (MSA) is important for prognost ic and therapeutic purposes. In order to evaluate the diagnostic capability of two tests reflecting these items, patients fulfilling strict clinical c riteria for PD (n = 35), MSA (n = 36) and PSP (n = 14), were consecutively included. An analysis of neurofilament protein (NFL), a marker of axonal de generation in the cerebrospinal fluid (CSF) and a levodopa test, recorded w ith optoelectronic technique were performed. Using discriminant analyses, t he test's abilities to predict the clinical PD or non-PD (MSA and PSP) diag noses were compared. Whereas the CSF-NFL and levodopa tests predicted 79 an d 85% correct diagnoses respectively, the combined test predicted 90% corre ct diagnoses. We conclude that the CSF-NFL and levodopa tests provide detai led information of clinical variables on which the clinical diagnostic crit eria are based. As they are pathologically unrelated, the diagnostic precis ion increases compared to clinical diagnoses when they are combined. (C) 20 01 Elsevier Science Ltd. All rights reserved.