Objective: To evaluate a new parameter – Bradykinesia Index (BI) as an new objective measure within the BRAIN (BRadykinesia Akinesia INcoordination) tap test.

Background: The BRAIN tap test is an online keyboard finger tapping task that measures speed and accuracy of alternate tapping and has previously been validated in Parkinson’s disease (PD) (Noyce et al 2014). Bradykinesia is one of the hallmark motor symptoms of PD and defined by the Queen Square Brain Bank criteria as, “slowness of initiation of voluntary movement with progressive reduction in speed and amplitude of repetitive actions” (Hughes et al. 1992). Current tools for assessing bradykinesia and motor fluctuations have certain limitations. Clinical rating scales are subjective, non-linear and bradykinesia-related items on the MDS-UPDRS part III have low reliability. Patient diaries are time consuming, are met with low compliance, and are vulnerable to recall bias. The potential for the BRAIN tap test to measure bradykinesia and differentiate between patients and controls has not been investigated in past studies. A new parameter Bradykinesia Index (BI) is introduced.

Methods: 59 patients with mild-moderate stage PD (Hoehn and Yahr <2.5) were recruited and were compared with 59 controls. Instructions were provided prior to the test and subjects were asked to start the alternating finger tap test with each hand for 30 seconds. BI scores were calculated and correlated with the total motor UPDRS part III scores and subscores (finger tapping, hand movements, pronation/supination) in the ‘on’ and ‘off’ states for PD patients.

Results: BRAIN tap test parameter BI differentiated between ‘on’ and ‘off’ states (p<0.0001). BI also correlated with total motor UPDRS part III scores in the ‘off’ state (r = -0.46, p ≤ 0.0001) and ‘on’ state (r = -0.44, p ≤ 0.0001). BI showed decrement in finger tapping performance in 81.35% (48 out of 59) of the most affected upper limb in PD patients in the ‘off’ state, compared with 33.89% (20 out of 59) of controls using the non-dominant hand. BI differentiated between PD patients and controls with sensitivities of 46%, 58%, and 64% for specificities of 90%, 85% and 80% respectively.

Conclusions: BRAIN tap test is a simple, user-friendly method for assessment of upper limb motor symptoms of PD. Further work will focus on programming the new BI parameter within the software before further validation in additional patient groups.

« Back to 2016 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/objective-decrement-in-parkinsons-disease-a-new-parameter-for-the-brain-tap-test/