Reproducibility of standardized fine motor control tasks and age effects in healthy adults

Graphical tasks can provide objective measures of important motor symptoms of movement disorders such as Parkinson's disease (PD). These tasks could potentially be useful in clinical settings for (early) diagnosis and monitoring of such diseases. However, before such tasks can be used clinically, reproducibility needs to be investigated. The present study assesses the reproducibility of these graphical tasks including age-effects in healthy adults. Overall, performance on circle, spiral and zigzag tracing tasks and a writing task showed good reproducibility (intraclass correlation coefficients (ICC) > 0.7). Reproducibility was similar to the reproducibility of the Purdue pegboard task, which is an already validated fine motor control task. Reproducibility for the modified Fitts' task was moderate (ICC = 0.6). Reproducibility was higher in older participants compared to younger participants. To conclude, performance on graphical tasks, especially tracing and writing tasks, was reproducible in healthy adults, which is essential for future diagnostic and monitoring purposes in patients.