The influence of dopaminergic medication on balance automaticity in Parkinson’s disease

•Postural sway was increased with dopaminergic medication.•Medication most likely improved maneuverability, not decreased stability.•Medication did not improve balance automaticity (i.e., static balance measures).•Findings support the ‘capacity sharing model’ of dual-task interference. Studies have shown that dual-task standing balance in Parkinson’s disease (PD) is significantly diminished. Additionally, it is well accepted that dopaminergic medication improves dynamic balance (Berg Balance Scale, mini-BESTest), but standing balance (force platform posturography) may suffer. What remains unknown is how dopaminergic medication influences standing balance automaticity in PD. Does dopaminergic medication improve standing balance automaticity during a phoneme monitoring dual-task in PD? This was a cross-sectional study. Sixteen subjects with PD completed single- and dual-task standing with eyes open and eyes closed for 3 min each in off and on medication states. 95% confidence ellipse area, anterior-posterior sway velocity, medial-lateral sway velocity, and integrated time to boundary were calculated. Data were analyzed with a repeated measures ANOVA. Dopaminergic medication significantly increased ellipse area (p = 0.002) and decreased the performance on the secondary task (p = 0.004). Different eyes conditions (open vs. closed) significantly increased both sway velocities (anterior-posterior = p