Dual-task demands in various motor skills through Parkinson’s disease progression

–– Aim: The aim of this study was to investigate the effects of adding a cognitive task on the performance of three different motor tasks with different demands, discrete skills, serial skills and continuous skills, by individuals with mild, moderate, and severe idiopathic Parkinson’ disease (PD). We also investigate the effect of the cognitive task in the secondary task and the cost of the dual-task. Method: This is a cross-sectional study. Individuals with idiopathic PD were divided in three groups with respect to motor severity (mild, moderate and severe groups). Participants’ performances were assessed in single and DT conditions including Sit-to-Stand test (SST), Timed Up and Go (TUG), and 10-meter Walk test (T10W). Cognitive task used was verbal fluency Results: The results show that dual task impact the performance of all primary tasks. DT negatively affects the performance of the motor tasks. And there is a different impact according the severity of the disease, severe ones are more affected than mild and moderate. Conclusion: In conclusion, adding a concurrent cognitive task negatively affected the performance of discrete, serial and continuous motor tasks, and this effect is more noticeable in severe than in mild patients. Under dual-task conditions, patients improved their cognitive task performance for gait and TUG, suggesting a prioritization of the secondary task for these tasks. There was no difference between the costs of the three tasks.