Objective: To investigate the correlation between patient-based vs. clinician-based L-Dopa effects on PD symptoms in tremor-dominant patients.

Background: Medication adjustments are often solely based on patient reports. Therefore, it is crucial to know how well clinical ratings and patient ratings correlate, and which factors influence the patient’s judgments about medication effectiveness. A better understanding has impact on clinical practice, but also on the use of subjective assessment scales in scientific research.

Methods: A standardized L-Dopa challenge test was performed in 42 tremor-dominant PD patients. Clinical scores (MDS-UPDRS part III) were collected OFF and ON dopamine (200/50 mg levodopa-benserazide). In both sessions, resting tremor intensity was quantified at REST and during cognitive co-activation (COCO), using accelerometry. Patients rated L-Dopa effect separately for tremor and for bradykinesia/rigidity, after the standardized L-Dopa challenge-test, using visual analogue scales (VAS). We tested whether the correlations between patient ratings (VAS) and clinical ratings (UPDRS, accelerometry) differed between symptoms, and whether (for resting tremor) the correlations differed between contexts (REST vs. COCO).

Results: Patients had a clear effect of L-Dopa, both for bradykinesia/rigidity (49% improvement) and for tremor (40%). L-Dopa reduced tremor power (p<0.001), while COCO increased it (p<0.01). We found similar patient-clinical correlations for bradykinesia/rigidity (R=0.46, p<0.01) and tremor (R=0.60, p<0.001; no significant difference; p=0.32). For tremor, patients’ rating correlated better with accelerometry improvements during COCO (R=0.46; p<0.01) than during REST (R=0.23, p=0.069; difference between correlations coefficients: z=-1.69, p<0.05).

Conclusions: The patients’ subjective experience of L-Dopa effectiveness on tremor is largely based on the ability of L-Dopa to reduce tremor during stress (COCO). This underlines the importance of using a cognitive co-activation task during clinical evaluation of tremor. It also implies that future therapies should focus on reducing Parkinson’s tremor during stressful situations.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/the-patients-perspective-the-effect-of-dopamine-on-parkinson-symptoms/