Objective: We aimed to evaluate if micrographia in Parkinson’s disease (PD) patients correlates with the severity of bradykinesia and whether or not micrographia is improved by MRI-guided focused ultrasound subthalamotomy (FUS-STN) or levodopa.

Background: Micrographia (i.e. small handwriting) is a historically recognized clinical feature of PD, which can be present in up to 30% of patients, even before diagnosis is established. Bradykinesia is a cardinal manifestation in PD, but the relationship between micrographia and bradykinesia is uncertain. Furthermore, there is no data or consensus regarding the degree of improvement of micrographia after treatment with levodopa or FUS-STN which do reduce bradykinesia.

Method: This study was designed to recruit PD patients in various clinical stages, including early-, mid-, and advanced-stage, and age-gender matched healthy controls. Also, we recruited PD patients treated with FUS-STN. Subjects were asked to write several words including non-native languages, sentences and draw figures on a digital tablet for subsequent quantitative analysis. We quantified bradykinesia on upper limbs with the Kinesia One system. Patients with motor fluctuations were assessed both in off- and on-medication and patients treated with FUS-STN were assessed at baseline and 3 months after the procedure.

Results: At this moment, we have recruited 5 PD patients, and pilot analysis was performed. Their mean age was 60.8 years old, and all of them were right-handed. Mean disease duration and UPDRS part Ⅲ score in off-medication were 4.7 and 29.6 respectively. We recorded finger tapping for 10 seconds and compared the first 5 taps and the last 5 taps, however, at this moment there is no significant decrease in the kinematic parameters. Handwriting parameters like fluency, letter size, and writing dynamics are also recorded, although more subjects are necessary to perform statistical analysis. Further evaluation will explore the impact of levodopa and FUS-STN on these parameters. We will present the final result at the time of the congress.

Conclusion: Our study will certainly provide insights into the relationship between micrographia and bradykinesia in PD, contributing to a better understanding of their interaction across different disease stages. Moreover, we aim to explore whether pharmacological and other therapeutical interventions modify handwriting characteristics, offering potential therapeutic implications.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/quantitative-assessment-of-micrographia-and-bradykinesia-in-parkinsons-disease/