Validation of the "L-DOPA test" for diagnosis of restless legs syndrome.
We developed and validated a standardized test procedure to evaluate the accuracy of the supportive diagnostic criterion "response to dopaminergic treatment" in restless legs syndrome (RLS). Forty-eight patients who fulfilled at least three of the four essential criteria for RLS, thus including uncertain clinical cases for a nonexpert, were recruited. Patients received a preliminary diagnosis of RLS or non-RLS. All patients underwent a polysomnography (PSG) and were then asked to perform the diagnostic L-DOPA test at home, which consisted in the application of one single dose of 100/25 mg L-DOPA/benserazide and a subsequent observational period of 2 hours. Before, and in 15-minute intervals after, drug intake, the patients rated the severity of the "symptoms in the legs" and the "urge to move the legs" using a 100-mm visual analogue scale. Considering a 50% improvement as a positive test result, we found a sensitivity of 88% ("symptoms in the legs") and 80% ("urge to move the legs") with a specificity of 100% for both test items. A rate of 90% or 83% of all patients could be correctly diagnosed by the L-DOPA test. Both scales were able to predict the response to dopaminergic agents in the subsequent course of the treatment by 100%. The periodic leg movements arousal index as assessed by polysomnography was less appropriate for the prediction of the correct diagnosis. We recommend the L-DOPA test for diagnostic decision making in all patients with an unclear RLS diagnosis according to the essential diagnostic criteria of the International RLS Study Group.
Stiasny-Kolster
Karin
K
Department of Neurology, Center of Nervous Diseases, Philipps-University, Marburg, Germany. stiasny@med.uni-marburg.de
Kohnen
Ralf
R
Möller
Jens Carsten
JC
Trenkwalder
Claudia
C
Oertel
Wolfgang H
WH
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001545:Benserazide; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007980:Levodopa; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects; D010147:Pain Measurement; D017286:Polysomnography; D011237:Predictive Value of Tests; D012148:Restless Legs Syndrome / Q000175:diagnosis*
D007980:Levodopa; D001545:Benserazide