Objective: To investigate the differential effects of dopaminergic therapy on bradykinesia and limb-kinetic apraxia in PD patients using kinematic analysis. Additionally, transcranial magnetic stimulation (TMS) was employed to further elucidate the underlying mechanisms of treatment.
Background: Bradykinesia is one of the primary motor symptoms in Parkinson’s disease (PD)1. However, other cognitive-motor disorders, such as limb-kinetic apraxia2, may contribute to motor dysfunction, influencing the variability in treatment responses3.
Method: 25 patients with PD were assessed in both OFF- and ON-medication states, along with 24 age- and gender-matched healthy controls (HC). Kinematic analysis was performed to evaluate bradykinesia (using a finger-tapping task) and limb-kinetic apraxia (using a 10-second coin rotation task). Corticospinal excitability was examined through TMS, which measured resting motor thresholds, motor-evoked potential input/output curves, short-interval intracortical inhibition, and interhemispheric inhibition.
Results: In the OFF-medication state, PD patients exhibited slower velocity, progressive reduction in amplitude (sequence effect), and decreased regularity in finger-tapping movements compared to HC. Similarly, slower velocity and altered movement regularity were observed in the coin rotation task in PD patients OFF medication compared to HC. Dopaminergic therapy improved finger-tapping velocity but had no significant effect on other finger-tapping parameters or the coin rotation task, highlighting a differential impact on the two motor tasks. Increased M1 excitability was associated, to variable extent, with impaired motor performance, such as slower velocity and/or altered movement regularity, during both the finger-tapping and coin rotation tasks. No such correlations were observed in the ON state. Additionally, no correlations were found between changes in kinematic parameters from the OFF to the ON state and the concurrent changes in TMS parameters.
Conclusion: The differential impact of treatment on bradykinesia and limb-kinetic apraxia in PD may suggest distinct pathophysiological mechanisms possibly involving distributed cortical and subcortical systems with varying sensitivity to dopaminergic therapy.
References: 1. Bologna M, Guerra A, Paparella G, Giordo L, Alunni Fegatelli D, Vestri AR, Rothwell JC, Berardelli A. Neurophysiological correlates of bradykinesia in Parkinson’s disease. Brain. 2018 Aug 1;141(8):2432-2444. doi: 10.1093/brain/awy155. PMID: 29901693.
2. Heilman KM. Hugo Liepmann, Parkinson’s disease and upper limb apraxia. Cortex. 2020 Oct;131:79-86. doi: 10.1016/j.cortex.2020.05.017. Epub 2020 Jul 21. PMID: 32801083.
3. Gebhardt A, Vanbellingen T, Baronti F, Kersten B, Bohlhalter S. Poor dopaminergic response of impaired dexterity in Parkinson’s disease: Bradykinesia or limb kinetic apraxia? Mov Disord. 2008 Sep 15;23(12):1701-6. doi: 10.1002/mds.22199. PMID: 18649388.
To cite this abstract in AMA style:
M. de Riggi, G. Paparella, A. Cannavacciuolo, D. Birreci, D. Costa, M. Passaretti, L. Angelini, M. Bologna. Differential Effect of Dopaminergic Treatment on Bradykinesia Features and Limb-kinetic Apraxia in Parkinson’s Disease [abstract]. Mov Disord. 2025; 40 (suppl 1). https://www.mdsabstracts.org/abstract/differential-effect-of-dopaminergic-treatment-on-bradykinesia-features-and-limb-kinetic-apraxia-in-parkinsons-disease/. Accessed October 5, 2025.« Back to 2025 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/differential-effect-of-dopaminergic-treatment-on-bradykinesia-features-and-limb-kinetic-apraxia-in-parkinsons-disease/