Objective: The aim of this study was to compare the BRAIN test performance of people with subjective RBD (sRBD, defined by RBD screening questionnaire score >5³) to controls.

Background: The BRadykineisa Akinesia INcoordination (BRAIN)¹ test is a 30-second web-based alternating finger keyboard tapping test which was validated to evaluate motor dysfunction in Parkinson’s disease (PD). It is part of the online assessments in the PREDICT-PD study. In a previous study we found that patients with polysomnography (PSG)-confirmed REM Sleep Behaviour Disorder (RBD) had slow and erratic keyboard tapping².

Method: A cross-sectional study was carried out to compare the BRAIN test performance of people with subjective RBD (sRBD, defined by RBD screening questionnaire score >5³) to controls. BRAIN kinetic parameters included kinesia score (KS, taps over 30s), akinesia time (AT, mean dwell-time on each tap) and incoordination score (IS, variance of traveling time between taps). We undertook logistic regression models adjusted for age and sex to determine the association between kinetic parameters (independent variable) and the presence of sRBD (dependent variable).

Results: We tested 2512 participants in PREDICT-PD (310 sRBD people and 1907 controls). The sRBD group was younger (64.90 years (SD 9.07) vs 66.67 years (SD 6.84), p<0.001) and more likely to be male (51.2% vs 37.1%, p<0.001) than the controls. The sRBD group performed the BRAIN test more slowly than controls (KS: 57.05 taps vs 60.89 taps; 95% CI 2.32-5.36, p<0.001) and with greater incoordination (IS: 9.15 vs 8.91; 95% CI 0.12-0.36, p<0.001). Logistic regression analysis adjusted for age and sex showed that IS had the strongest association with sRBD. The odds of having sRBD was 1.13-fold greater per 1 unit change in the IS (95% CI 1.07-1.20, p<0.001). There was nominal evidence that AT was also associated with sRBD (OR, 1.01; 95% CI 1.00-1.01, p<0.001). KS did not show any association with sRBD after adjusting for age and sex.

Conclusion: There is some evidence that individuals with sRBD had an abnormal keyboard tapping which resembles what we found previously in patients with PSG-confirmed RBD. Remote keyboard tapping may have utility as a screening tool to select people with sRBD who might warrant a PSG study and subsequent closer monitoring.

References: 1. Noyce AJ, et al. Bradykinesia-akinesia incoordination test: validating an online keyboard test of upper limb function. PLoS One. 2014 Apr 29;9(4):e96260.
2. C. Simonet et al. Remote keyboard tapping: potential signatures of early motor dysfunction in isolated REM sleep behaviour disorder, MDS International Congress of Parkinson’s disease and Movement Disorders 2022; poster.
3. Stiasny-Kolster, et al. The REM sleep behavior disorder screening questionnaire–a new diagnostic instrument. Mov. Disord. 2007 (22).

« Back to 2023 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/keyboard-tapping-performance-in-people-with-subjective-rem-sleep-behaviour-disorder/