Abstract
AIMS: Parkinson disease (PD) is highly heterogeneous in response to antiparkinsonian drugs. We herein aimed to identify PD subtypes based on dopamine responsiveness in three key motor signs (resting tremor, rigidity, and bradykinesia). METHODS: The acute levodopa challenge test was performed. Improvement rates in resting tremor, rigidity, and bradykinesia were calculated. A total of 228 PD patients were included for further analysis. Subtypes were determined by k-means clustering based on the improvement rates. RESULTS: Four subtypes were identified: rt-r-b, moderate improvement in resting tremor, rigidity, and bradykinesia; RT-r-b, marked improvement in resting tremor but moderate improvement in rigidity and bradykinesia; RT-R-B, marked improvement in resting tremor, rigidity, and bradykinesia; rt-R-B, moderate improvement in resting tremor but marked improvement in rigidity and bradykinesia. These subtypes also differed in other motor and nonmotor symptoms. CONCLUSION: Our study reveals four distinct subtypes in PD patients based on dopamine responsiveness. Our findings provide a novel insight into understanding PD heterogeneity and facilitate precision treatment.