Single oral levodopa challenge test in de novo patients with idiopathic Parkinson's disease and multiple system atrophy

ABSTRACT

BACKGROUND: In the previous literature, single oral levodopa challenge test has been reported as one of the methods differentiating multiple system atrophy (MSA) from idiopathic Parkinson's disease (IPD). However many of the patients included in these studies had been on levodopa treatment for a variable period when they were examined. We performed this study to determine the value of single oral levodopa challenge test in differential diagnosis between IPD and MSA. METHODS: After a single oral dose of SinemetR(25/250), we assessed the improvement of motor function in 54 de novo patients with parkinsonian symptoms (33 with IPD and 21 with probable MSA). We measured the time taken to finish 20 taps with unilateral hand on two marks separated 20 cm apart and to walk 10 meter from a sitting position and return. Such performances were assessed 5 times before the medication, every 15 min for first 2 hrs after the medication, and then every 30 min for the next 4 hrs. RESULTS: The mean of the age, mean of the duration of disease and mean of the Hoehn and Yahr scale score were not significantly different between the patients with IPD and those with MSA. The mean of the unified Parkinson's disease rating scale score between the patients with IPD and MSA was not significantly different. Baseline scores of the hand and the walking performance were not significantly different. The median of the time interval between the levodopa intake and maximum beneficial effects, mean of the objective improvement at the peak, and mean of the amount of maximum subjective improvement comparing to the baseline was not significantly different between the patients with IPD and MSA. Also there were no significant differences in all measurements between the patients with striatonigral and olivopontocerebellar type of MSA. CONCLUSIONS: These findings suggest that single oral levodopa challenge test is not so helpful for the differential diagnosis between de novo patients with IPD and MSA.