Motor markers in the progression of parkinson's disease

Introduction: Parkinson's Disease (PD) is a progressive neurodegenerative disorder that significantly impacts patients' quality of life through a combination of motor and non-motor symptoms. The primary approach to diagnosing and monitoring PD relies on clinical examinations. However, the fact that current methods are often based on subjective assessments and clinical observations can lead to uncertainties and inconsistencies during the follow-up process. An objective examination method in PD would facilitate more accurate treatment, monitoring, and scientific research. Aim:This study aims to develop a method that can express the specific motor symptoms of PD in numerical values, thereby allowing for a more accurate and standardized evaluation of disease progression. Methods: The study was conducted on 63 patients followed at the Movement Disorders Clinic of Ankara University Faculty of Medicine Hospital between 2020 and 2024. Participants' demographic and clinical data were collected using cognitive assessment tools such as the Mini-Mental State Examination (MMSE) and the Clock-Drawing Test. Motor performance was assessed with the MDS-UPDRS Part 3, Nine Hole Peg Test (NHPT), Key Tapping Test, and the Timed Up and Go (TUG) Test. Data were analyzed using SPSS 26.0 software. The cross-sectional correlations of the tests and the correlations of their changes over time were evaluated. Regression analysis was performed to determine the relationship between changes in MDS-UPDRS Part 3 and changes in the NHPT, Key Tapping Test, and TUG Test. Results:At the cross-sectional level, the NHPT and Key Tapping Test showed a strong correlation with MDS-UPDRS Part 3, while the TUG Test showed a moderate correlation. When all PD patients were considered, no significant correlation was found between changes in MDS-UPDRS Part 3 and changes in these tests. Among PD patients without dyskinesia and advanced-stage disease (stages 4–5), the changes in the tests were found to correlate with a 0.750 correlation coefficient with changes in MDS-UPDRS Part 3, explaining 56.2% of the variance. Conclusion: In patients who dyskinesia does not affect the examination and who are not in advanced stages, changes in MDS-UPDRS Part 3 can be reasonably explained by the Key Tapping Test alone, whereas the NHPT and TUG Test provide insufficient explanatory power. A 1-point worsening in the non-dominant hand Key Tapping Test was found to be associated with a 1.518-point worsening in MDS-UPDRS Part 3. The dominant hand NHPT, non-dominant hand Key Tapping Test, and TUG Test together were found to highly predict changes in Part 3. When Part 3 was separately evaluated for upper and lower extremities, changes in the tests were found to be unable to predict changes in the lower extremities. In patients who dyskinesia does not affect the examination and who are not in advanced stages, the Key Tapping Test, either alone or combined with other tests, can be used as a substitute for MDS-UPDRS Part 3 for assessing the upper extremities.