RESUMO
BACKGROUND: Rapid eye movement (REM) sleep behavior disorder (RBD) is one of the most specific prodromal indicators for Parkinson's disease (PD). OBJECTIVES: To test the validity of the RBD-Screening Questionnaire (RBDSQ) in assessing RBD in early PD. METHODS: The RBDSQ was completed before video-supported polysomnography (vPSG) by 134 de novo PD patients, 109 matched controls without neurological disorder (CTR) and 30 subjects with idiopathic RBD (iRBD) without clinical signs of PD; results were compared with vPSG-confirmed RBD diagnosis. RESULTS AND CONCLUSIONS: Sensitivity/specificity of the RBDSQ for the PD cohort were 0.44/0.84 at the previously published cut-off score of 6 for PD patients, and the area under the curve (AUC) 0.68 (95% CI, 0.56-0.79). By contrast, in the iRBD/CTR cohort the RBDSQ (cut-off = 5) had a sensitivity/specificity of 0.97/0.84 and an AUC of 0.95 (95% CI, 0.90-1.00). Subanalysis of question 6 only (4 subitems asking for dream enactment) at a cut-off score of 1 revealed a sensitivity of 0.74 and a specificity of 0.70 for the de novo PD cohort, AUC was 0.74 (95% CI, 0.63-0.84). RBDSQ is an insufficient screening tool for RBD in de novo PD. New screening tools for RBD assessment need to be developed.
RESUMO
BACKGROUND: The precise clinical diagnosis of Parkinson's disease (PD) can be difficult in the early stages. Diagnostic criteria include the response of key motor features to levodopa as a supportive prospective criterion. Data are sparse on the diagnostic value of the acute levodopa challenge test (LDCT) in patients with de novo PD. The objective of this study was to validate the LDCT as a tool in the early clinical diagnosis of PD. METHODS: We performed the standardized LDCT with 250 mg levodopa in the prospective longitudinal cohort study "DeNoPa," comprising 159 patients with de novo PD, and carried out longitudinal clinical follow-up for 24 months. Motor assessments at baseline using the motor part (part III) of the Unified Parkinson's Disease Rating Scale before and 1 hr after drug administration were documented. The optimal cutoff score on the LDCT was calculated using the Youden index. RESULTS: Clinical reassessment of 144 patients who returned for follow-up confirmed the diagnosis of PD in 120 patients (83%). In 24 patients (17%), the initial diagnoses were revised and classified as other neurologic disorders. The optimal cutoff at 33% improvement of motor symptoms on the part 3 of the Unified Parkinson's Disease Rating Scale during the LDCT reached a sensitivity of 70% a specificity of 71%. The positive and negative predictive values were 92% and 32%, respectively. Sensitivity (91%), specificity (79%), and positive/negative (96%/63%) predictive values improved with the addition of further clinical information (urinary incontinence, fainting, asymmetric tremor, and amount of further drug-intake). CONCLUSIONS: The LDCT is a reliable tool in the early diagnosis of PD. The accuracy of this test can be further improved by additional, easy-to-acquire clinical information provided by patients. © 2017 International Parkinson and Movement Disorder Society.