Resting tremor in Parkinson disease: a negative predictor of levodopa-induced dyskinesia.

BACKGROUND It is unclear whether patients with different clinical subtypes of Parkinson disease (PD) differ in their risk of developing levodopa-induced dyskinesia (LID) and whether resting tremor is negatively correlated with this risk. OBJECTIVES To determine whether resting tremor as an initial manifestation of PD negatively correlated with subsequent occurrence and severity of LID and to study the correlations between LID and other epidemiological factors (eg, age at onset of PD and duration of PD). DESIGN Logistic regression analysis was used to determine predictive factors of LID. Spearman rank correlations between LID and epidemiological factors and motor signs (including tremor) were calculated. SETTING Institutional tertiary referral center for movement disorders. PATIENTS Cohort of 85 patients with PD. MAIN OUTCOME MEASURE Occurrence of LID according to the Unified Parkinson Disease Rating Scale part IV. RESULTS Resting tremor as an initial manifestation of PD was associated with reduced risk of developing LID independent of other predictors of LID (duration of PD, axial signs, and levodopa dose). CONCLUSION Resting tremor as an initial manifestation of PD predicts lower probability of developing LID under levodopa treatment.