Objective: 1. To develop a web-based test that objectively measures distal bradykinesia,
2. To validate the test by assessing PD patients and healthy controls, and correlating to MDS-UPDRS scores,
3. To determine whether the test can monitor motor fluctuations in PD patients

Background: Disability in Parkinson’s disease (PD) is assessed by the MDS-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), which is subject to inter-/ intra-rater variability and fails to capture some specific kinematics of motor impairment. The BRadykinesia Akinesia INcoordination (BRAIN) test is a previously validated keyboard tapping test, which predominantly captures proximal upper-limb motor dysfunction. Here, a new Distal Bradykinesia Tapping (DBT) test was developed to assess distal upper-limb motor impairment. Kinetic parameters of the test include kinesia score (KS20, number of key taps over 20 seconds), akinesia time (AT20, mean dwell time on each key) and incoordination score (IS20, variance of travelling time between key taps).

Method: The DBT test was validated in 45 PD patients and 24 controls, alongside the original BRAIN test. KS20, AT20 and IS20 were compared between groups and correlated with MDS-UPDRS motor scores in patients. An additional 10 PD patients were recruited to assess the utility of the DBT test in monitoring motor fluctuations.

Results: All three DBT parameters differentiated patients from controls, with KS20 giving a sensitivity of 75% for 85% specificity and AUC >0.8. The combination of DBT and BRAIN test parameters significantly improved diagnostic discrimination to AUC 0.9. KS20 and AT20 correlated with MDS-UPDRS motor scores (Pearson’s r=-0.49, p<0.001 and r=0.54, p<0.001, respectively). When monitoring fluctuations, the DBT test was able to detect subtle changes in motor function (IS20 p=0.04), which were not reflected by MDS-UPDRS finger tapping sub-scores (p=0.10).

Conclusion: The DBT test appears to be a user-friendly and accurate method of assessing distal motor dysfunction in PD. Moreover, it could potentially serve as a low-cost, freely available tool for longitudinal monitoring of PD motor complications.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/a-new-web-based-tapping-test-for-measuring-distal-bradykinesia-in-parkinsons-disease/